Title of Invention	METHOD AND DEVICE FOR MANUFACTURING PLUNGERS FOR MEDICAL SYRINGERS AND A SYRINGE THEREOF.
Abstract	Method for manufacturing plungers for medical syringes, whereby such a plunger: (3) consists of at least two parts namely a longitudinal plunger body (4) made of plustic and a piston body (5) Provided at the from end of the plunger body (4) which consists of a plastic which is softer than the plastic of the plunger body (4), charecterised in that such a plunger (3), or at ieast a part (36) thereof, is formed by first manufacturing the piston body (5) and then the plunger body (4). of at least a part (37) of this plunger body (4), by means of injection moulding , whereby the piunger body (4), of the above-mentioned part (37) thereofo, is injected against the piston body (5).

Title of Invention

METHOD AND DEVICE FOR MANUFACTURING PLUNGERS FOR MEDICAL SYRINGERS AND A SYRINGE THEREOF.

Abstract

Method for manufacturing plungers for medical syringes, whereby such a plunger: (3) consists of at least two parts namely a longitudinal plunger body (4) made of plustic and a piston body (5) Provided at the from end of the plunger body (4) which consists of a plastic which is softer than the plastic of the plunger body (4), charecterised in that such a plunger (3), or at ieast a part (36) thereof, is formed by first manufacturing the piston body (5) and then the plunger body (4). of at least a part (37) of this plunger body (4), by means of injection moulding , whereby the piunger body (4), of the above-mentioned part (37) thereofo, is injected against the piston body (5).

Full Text	-1- Method_and device _for manufacturing plungers for medical syringes/ plungers obtained thereby, as well as a syringe 5 for medical purposes. The present invention concerns methods for manufacturing plungers for medical syringes, as well as devices applying such method and plungers obtained according to said method. 10 Further, it also concerns different embodiments of syringes, in particular syringes with special embodiments of plungers, In particular, the invention concerns a method for 15 manufacturing such, plungers out of plastic. By syringes should be understood in this case all recipients provided, with a piston or plunger with which liquid can be sucked up in the recipient and/or can be 20 pressed out of the recipient. Examples thereof are injection syringes and dose syringes. The above-mentioned plungers, which are designed to be pushed in a slidable manner in a usually cylindrical 25 recipient, as is known consist of a longitudinal plunger body upon which is fixed a piston body at the front in the shape of a head. The plunger body is usually made of a relatively hard plastic, whereas the piston body is made of a softer material which guarantees a good sealing against 30 the cylinder wall of the syringe. WO 2004/035289 P€T/BE2003/000157 -2- The above-mentioned parts, the plunger body on the one hand and the piston body on the other hand, are traditionally made entirely separately, to be subsequently assembled, either manually or by means of an assembly machine. 5 The two aforesaid parts of the known plungers are traditionally attached to each other by means of a sort of snap-in system, in particular by means of collars meshing behind one another, such that the piston body can be 10 pressed down on the far end of the plunger body. As, according to the known technique, the two parts of a plunger are manufactured separately and have to be subsequently assembled, this technique is relatively 15 complicated, time-consuming and expensive. There is also a chance that the parts do not perfectly mesh during the assembly, so that problems may arise at a later stage, when the plunger is pushed in the cylindrical body of the syringe or the like. 20 According to newer techniques, the two parts of the plunger are provided onto each other in a single injection-moulding machine, so that no separate mechanical mounting is required and the above-mentioned disadvantages are 25 excluded. A first example thereof is known from EP 1.099.449. The plunges body is hereby first injection-moulded out of hard plastic in a mould impression, after which a piston body 30 made of a softer plastic is then formed on the plunger body by enlarging said mould impression near the front end of WO 2004/035289 PCT/BE2003/00157 -3- the formed plunger body and by then injecting the softer plastic in the space which has thus become available. In order to be able to enlarge the above-mentioned mould. 5. impression, the mould is provided with a sliding part. A disadvantage of the use of such a sliding part consists in that a sub edge may be created on the front side of the formed piston body at the transition between said sliding part and the surrounding mould parts , which is undersirable 10 in medical applications since, at the height of said sub edge, material particles may come off and thus end in the reservoir of the syringe, and thus also in the medical liquid to be injected. 15 The injection of the plastic For forming the piston body is not simple either in this case. According to a first known possibility, the plastic may be injected laterally, which results in gate points being created in the side wall of the piston body, which is not desirable in practice. 20 According to a second known possibility, the injection takes place through a supply duct formed, in the plunger body. This prevents the formation of gate points on the front side or side wall of the piston body, but a disadvantage consists in that rather complex additional 25 means are required to form such a supply duct through the plunger body. A second example is known from US 5.902.276, whereby a plunger body is formed in a first mould and a thin layer of 30 soft plastic is subsequently provided in a second mould over the front end of said plunger body, in order to thus WO 2004/035289 PCT/BE2003/O00157 -4- realise a piston body. The soft plastic is hereby injected via the back side of the piston body to be formed. However, a disadvantage hereby is that the presence of the already formed plunger body leaves little room to provide a 5 nozzle in an efficient manner. Also, several nozzles per piston body have to be provided in order to make sure that the plastic spreads sufficiently through the mould impression. Also, the devices required to this end are relatively complex. 10 The present invention in general aims a method for manufacturing plungers for medical syringes out of plastic which is new and offers several advantages as such, such as for example an efficient manufacturing. Also, it aims a 15 method which makes it possible to exclude the disadvantages of the above-mentioned known methods, at least when certain preferred embodiments are applied. To this end, according to a first aspect, it concerns 20 method for manufacturing plungers for medical syringes, whereby such a plunger consists of at least two parts, namely a longitudinal plunger body made of plastic and a piston body provided, at the front end of the plunger body which consists of a plastic which is softer than the 25 plastic of the plunger body, characterised in that such a plunger is formed by first manufacturing the piston body and then the plunger body by means of injection moulding, whereby the plunger body is injected against the piston, body. 30 WO 2004/035289 PCT/BE2003/000157 -5- Since, of each plunger the piston body is formed first, and then the plunger body, the liquid plastic for forming the plunger body is pressed against the supple plastic of the already formed priston body, as a result of which this 5 supple plastic is pressed in somewhat elastically, so that a particularly tight fit of the piston body on the plunger body is obtained, in the end. By first forming the piston body and then the plunger body, 10 this also offers the advantage that the plastic for the piston body can be easily provided via the side of the mould Impression which is meant to form the back side of the piston body. In this manner, the formation of flash lines and gate points on the piston body can be easily 15 excluded without any relatively complicated constructions for the supply of plastic being required Hence, the piston body will preferably be formed such that its front side and side wall are entirely free of flash lines and/or gate points for the plastic. 20 In particular, the piston body is preferably formed in a mould, impression whose walls, which connect to the front side and the side wall of the piston body to be formed, are part of one and the same undivided mould part. 25 The plastic for forming the piston body is preferably provided via the back side of the piston body to be formed in the mould impression concerned, possibly centrally, such that an even spread of the plastic in the mould impression 30 is promoted. Moreover/ a single nozzle may then be sufficient for the infection of said plastic. WO 2004-035289 PCT/BE2003/000157 -6- As the piston body is formed first and this piston body consists of an elastically bendable material, this offers the advantage that the piston body, even when it has an 5 inwardly directed collar and/or a part defining a counter draft, can be easily taken out of the mould, simply by pulling the mould part concerned loose, from. behind said collar or out of the counter draft. 10 What precedes does not exclude, however, that according to another preferred embodiment, the piston body and the plunger body are connected to each other merely by the adhesion between the plastics out of which they are made, in particular without any parts meshing behind each other,. 15 counter drafts and the like thereby being realised. For, by making use of suitable plastics, for example the types of plastic mentioned hereafter, it is possible to obtain an adhesion which is sufficiently large without any explicit mechanical lock in the shape of meshing parts being 20 required. This offers as an advantage that the mould for forming the piston body can be opened effortlessly, without the formed piston body coming out of the mould impression in an unwanted manner. 25 According to yet another possibility, use can also be made of a folding core, which makes it possible to form inwardly directed parts on the piston body. By folding the core before it is removed from the formed piston body, it can subsequently be removed from said piston body without any 30 tensile force being exerted on the piston body. WO 2004/035289 PCT/BE2003/000157 According to the most preferred embodiment, the above- mentioned method is characterised in that the piston body is formed in a first mould impression, after which, said piston body, while it is still being held in the first 5 mould impression or a part thereof, is presented to a second mould impression in which the plunger body is then injected against the piston body by means of injection moulding, whereby mould impressions are applied having such a shape that the obtained plunger body and piston body are 10 connected to one another thanks to their shape and/or thanks to the adhesion between the used plastics. By making use of two mould impressions instead of one mould impression which is locally enlarged after a first part has been moulded, this offers the advantage that the mould 15 parts used thereby for forming the piston body and the plunger body respectively can be optimised individually. preferably, the method is also characterised in that, while a plunger body is being formed connected to a piston body, 20 a subsequent piston body is formed simultaneously by means ox the same nozzle with. Which the first piston body is realised, but in another mould impression. This allows for an efficient production whereby, during each injection cycle, a piston body as well as a plunger body are formed. 25 The piston body is preferably formed in a mould with mould parts whose partial surface mainly coincides with the back side Of the piston body to be formed or extends parallel thereto. This makes it possible, after the piston body has 30 been formed/ to simply present the mould, part in which the piston body is provided with the side defining the above- WO 2004/035289 PCT/BE2003/000157 -8- mentioned partial surface against the mould parts in which the plunger body is formed, without any complex movements of the mould parts being required. 5 The piston body is preferably made of a thermoplastic elastomer, while the plunger body is made of polypropylene or the like - It should be noted that the invention also concerns 10 embodiments whereby not the entire plunger body is injected against the piston body, but merely a part of this plunger body is injected against the piston body, after which the obtained part, formed of the aforesaid part and the piston body, are connected afterwards to a second, individually 15 manufactured part of the plunger body, for example via a mechanical coupling between both parts. The above- as rationed part which, is injected against the piston body is preferably made in the shape of an insert which makes it possible to make a connection to the rest of the plunger 20 body at a later stage, as mentioned above. By an insert is meant that the above-mentioned part is only limited in size and has been mainly designed to form a connection with the piston body on the one hand, by means of embedment, and to form a part which can be easily connected to the rest of 25 the plunger body as such on the other hand, for example by means of a mechanical coupling. According to a special embodiment, when realising such a plunger or a part thereof, also an accessory is formed 30 situated on the front side of the piston body, and which consists of a material which is different from the material WO 2OO4/O35289 PCT/BE2003/000157 of the piston body. Such an accessory can be of any nature whatsoever. A number of examples will be illustrated hereafter. As such an accessory is made of a separate material, this offers the advantage that its material 5 selection can be optimised as a function of the purpose of such an accessory. The material of the accessory will preferably consist of a plastic which is harder than the plastic out of which the piston body is formed. 10 By an 'accessory which is situated on the front side of the piston body' is meant every part which is accessible via the front side of the piston body. According to a first possibility, the above-mentioned. 15 accessory consists of a part which extends frontally from the front side of the piston body and which, when the plunger is situated in the syringe, can at least partially penetrate in the outlet of the syringe, which makes it possible to optimally empty the syringe. The use of such a 20 protruding part is known as such, but not that it is made of a different material, in particular another plastic than the one out of which the piston body is formed. By making use of different materials is thus obtained that independent material selections can be made whereby, when 25 the material of the piston body is selected, an optimisation of the sealing can be aimed at, whereas when the material of the protruding part is selected, an optimisation can be aimed at for this part in order to make it function optionally. Thus, for example, by selecting a 30 harder plastic, the protruding part can be made rattier WO 2004/035289 PCT/BE20O3/000157 -10- rigid, as a result of which it cannot bend and. will not be situated exactly in front of the outlet. According to another possibility, the above-mentioned 5 accessory consists of a part which makes it possible to create a passage between the front side and the rear side of the piston body when emptying the syringe, in order to prevent "the syringe being re-used, as a result of which, what is called a safety syringe is obtained- 1O The above—mentioned accessory is preferably made In one; of- the following shapes: — as a part which is made in one piece with the plunger body or a part thereof, and which is thus formed 15 simultaneously with the latter during the injection moulding, which offers the advantage that the accessory always remains perfectly aligned, for example remains axially aligned, and that no separate injection moulding cycle is required to form the 20 accessory; — as a separate part provided on the front side of the piston body; — as a separate part provided on the front side of the piston body, whereby this part is injected, against the 25 material of the piston body after the piston body has been formed, which offers the advantage that no liquid can leak away between both plastics. It should be noted that the invention can also be used for 30 realising short plungers, in particular plungers of the type designed to co-operate with a drive element. In WO 2004/035289 PCT/BE2003/000l57 -11- practice, such plungers are used for example in syringes or the like to slowly administer medical substances to a patient, in a dosed manner by means of a pump. Such a syringe is then connected to the patient via a catheter. 5 The plunger is connected to an automatically driven drive element of the pump, which moves very slowly when in use. Also, taking info account what precedes, the present invention, according to a second aspect, provides for a 10. method as described above, characterised in that, instead o£ being used to manufacture plungers with a longitudinal plunger body, it is used to manufacture plungers of the type which is meant to be used in combination with a drive element, whereby such a plunger then mainly consists of a 15 piston body and a plunger part, whereby this plunger; part is fit to co-operate with, such a drive element. It should also be noted that the characteristic in that a part is formed at the height of the piston body which 20 protrudes frontally from the front side, of the piston body and which, when the plunger is situated in the syringe, can penetrate at least partially in the outlet of the syringe, whereby this part and the piston body are formed of materials, in particular plastics which are injected 25 against one another, is advantageous when the piston body is moulded first and then the protruding part, as well as when the protruding part is moulded first and then the piston body. Fox, in both cases, the above-mentioned advantages remain applicable. 30 WO 2004/035289 PCT/BE2003/000157 -12- Taking into account what precedes, the present invention, according to a third aspect, also provides for a method for manufacturing plungers for medical syringes comprising aL least a piston body, characterised in that, at the piston 5 body, a part is formed which protrudes frontally from the front side of the piston body, and which, when the plunger is situated in the syringe, can penetrate at least partially in the outlet of the syringe, whereby this part is formed of a material which differs from, and is 10 preferably harder than the material of the piston body, and wthereby the piston body on the one hand and said, protruding part on the other hand are injected against one another, whereby the above-mentioned part is either or not made in one piece with a pLunger body belonging to the plunger. 15 According to a fourth aspect, the invention concerns a device for the application of the method according to the first and second aspect, characterised in that it at least consists of a number of mould parts which at least define a 20 first mould impression and a second mould impression to form the above-mentioned piston body and the above- mentioned plunger body respectively, or a Part of this plunger body; a motion mechanism which makes it possible to move the above-mentioned mould parts in relation to one 25 another and to position them differently so that, in a first position, a piston body can be injected, whereas in a second position, the plunger body or the aforesaid part thereof can be injected, against the piston body; and injection means to supply the plastic to be injected to the 30 aforesaid mould impressions respectively. WO 2004/035289 PCT/BE2003/000157 -13- According to the invention, the present device may have some more special additional characteristics, as explained in the following description and as described in the accompanying claims, which characteristics can be either or 5 not combined. It is clear that also devices which make it possible to realise the methods according to the aforesaid third, aspect fall within the scope of the invention. Its construction, 10 taking the description of the method as a basis. Ijes within the scope of the knowledge of any craftsman. Naturally, the invention also concerns plungers, as well as parts of plungers, made according to the preceding method, 15 as well as syringes that are equipped with such plungers. Finally, it should be noted that also the fact that the above-mentioned part protruding from the piston body consists of another material than the piston body itself, 20 is advantageous as such and offers several of the above- mentioned advantages, irrespective of whether this part has been formed by forming it together with the piston body in two successive injection moulding cycles, or in any other way whatsoever, for example made separately to be 25 subsequently connected to the piston body in a mechanical manner. Taking into account what precedes, the invention also concerns a syringe for medical purposes, according to a 30 fifth aspect, comprising at least a cylinder body with an outlet which is formed of a narrowed outlet part, as well WO 2004/035289 PCT/BE2003/000l57 -14- as a plunger working in conjunction with the cylinder body which is provided with a piston body and a plunger body, characterised in that the plunger comprises a part which protrudes frontally from tne front side of the piston body 5 and which can penetrate at least partially in the above- mentioned outlet part, whereby this part is formed of a material which is different from the material of the piston body, and. preferably consists of a plastic which is harder than the material out of which the piston body is formed. 10 In this case also, the part which protrudes frontally from the front side of the piston body, can be made according to either of the following two possibilities: - as a part which, is made in one piece with the plunger 15 body or made in one piece with a part of this plunger body - as a separate part provided at the piston body. In order to better explain the characteristics of the 20 invention, the following preferred embodiments are described, as an example only without being limitative in any way, with reference to the accompanying drawings, in which: 25 figure 1 represents a syringe which is equipped with a plunger made according to the method of the invention; figure 2 represents the plunger of the syringe from figure 1 in perspective; figure 3 represents a section according to line III- 30 III in figure 2; WO 2004/035289 PCT/BE20O3/000157 figures 4 to 8 represent a device according to the invention in different stages of the method; figures 9 and 10 represent a variant of the embodiment of a device according to the invention, when closed 5 and when opened respectively; figures 11 and 12 represent a plunger body as dismounted, and as mounted respectively, which has been realised according to a method of the invention; figure 13 schematically represents how the part which 10 is indicated by F13 in figure 11 can be realised by means of successive injection mounting cycles; figures 14 and 15 represent two variants of a plunger- body according to the invention, for a view similar to that in figure 11; 15 figures 16 and 17 represent a section of a syringe according to the invention, for two different positions of the plunger body; figure 18 shows how the plunger bodies for forming syringes according to figures 16 and 17 can be formed 20 by successive injection moulding cycles; figure 19 shows another special embodiment of a syringe according to the invention. A plastic syringe 1, as is used for medical applications, 25 mainly consists, as is represented in figure 1, of a recipient, in this case a cylinder 2 and a plunger 3. As is represented in greater detail in figures 2 and 3, the plunger 3 is composed of a plunger body 4 and a piston bociy 30 5, which in the given embodiment have such a shape that they mesh and as stich remain coupled. WO 2004/1135289 PCT/BE2003/000I57 -16- As is represented, the plunger body 4, which normally consists of a relatively hard. plastic, for example polypropylener preferably has a cross-shaped shaft 6 5 provided- with a collar 7 on one far end. The above-mentioned piston body 5, which is preferably made of a soft material, such as thermoplastic elastomer, is made in the shape of a head and is provided with an 10 excavation 9 on the rear side 8 which is partially confined by an inwardly directed collar 10, which co- operates with the collar 7 of the plunger body 4 . The invention aims a method and a device for manufacturing 15 plungers 3, or at least plungers of a srmilar type, in other words plungers 3 which consist of a plunger body 4 and a piston body 5 of different plastics. In order to illustrate the method, the construction of a preferred embodiment of a device 11 applied thereby, in particular a 20 combined injection mould, is first described hereafter by means of figures 4 to 6. The device 11 comprises a number of mould parts, in this case four, 12-13-14-15 respectively, defining `first' mould. 25 impressions 16 and a 'second' mould impression 17, for forming a first part of the plunger 3, namely the pistor; body 5, and a second part of the plunger 3, namely the plunger body 4 respectively. 30 The mould parts 12-13-14-15 together form three parts. 18- 13-20 Which can be mutually moved. WO 2004/1135289 PCT/BE2003/000I57 -17- The first part 18 is formed of the mould parts 12 and 14 which are mounted on a common support 21 which is preferably fixed. 5 The second part 19 is formed of the mould part 15 which is mounted on a support 22. This second part 19 can make a translation movement T1 in relation to the first part 18. 10 The third part 20 is formed of the mould part 13, which is mainly square and movable/ in particular is provided in an extending and rotatable manner on the support 22. The first mould impressions 16 are formed of cavities 23A- 15 23B-23C-23D provided on the surface of the mould part 13, in this case on each of the four sides thereof respectively, as well as of the wall part 24 of the mould part 12 with which the cavity which is turned towards this wall part 24 can be sealed. On the wall part 24 is 20 provided a protruding part 25 which is designed to form the excavation 9, and which is provided, with a recess 25A which is confined by a collar 25B. Hereby is obtained that the partial surface between the 25 mould parts 12 and 13 coincides with the rear side 8 of the piston body 5 to be formed, By means of the translation movement T1, the mould impression 16 can be opened, sealed respectively. 30 WO 2004/1135289 PCT/BE2003/000I57 -18- The second mould impression 17 is mainly formed of the cavities 26 and 27 provided the the surface of the mould parts 14 and 15 respectively. These cavities 26 and 27 hereby open into sides 28 and 29 as well as into sides 30 5 and 31 standing at right angles thereto. Further, these cavities 26 and 27 are situated such, that the mould impression 17 formed thereby, when the whole is closed, connects to the cavity 23B._ The longitudinal axes 10 of the mould impression 17 and the mould impression 16, in particular the cavity 23Bf are tvareby situated in each other's prolongation. The mould parts 14 and 15 can also be moved towards one 15 another and away from one another the means of the translation movement Tl. Further, the mould part 13 can make a translation movement T2 as well as a rotational movement R. 20 In order to realise the movements Tl, T2 and R, the device 11 is provided with a motion mechanism, consisting of drives which can move the three parts 18-19-20 in relation to one another, as will be further described, which are not represented for clarity' s sake. It should be poted that 25 the mould part 13 can also make a translation movement 13 in relation to the support 22 which has to make it possible for the mould part 13 to freely rotate. For the rotation, use is made of a rotating indexing 30 mechanism 32, whose axis of rotation 33 has a direction which is different from the direction or directions of WO 2004/035289 PCT/BE2003/000157 -19 - movement according to which the mould parts 12-13 and 14-15 open and close. It should be noted that, as represented in the figures, the 5 mould, parts 12-13-14-15 together- define three partial surfaces in other words surfaces whose composed mould opens and closes, which are situated in a stepped manner in relation to one another. This stepped construction allows for a compact construction. 10 Further, the device 11 comprises injection means for supplying the plastic to be injected to the aforesaid, mould impressions respectively which consist of nozzles 33—35 provided in the fixed part 18 and which preferably have 15 parallel longitudinal axes, and which also open in parallel partial surfaces. Moreover, the nozzle 34 extends centrally through the protrvitiing part 25 20 The working of the device 11, as well as the accompanying method, is described hereafter by means of the different positions represented in figures 4 to 8. 25 Figure 4 shows the composed mould when closed. A first plastic is hereby provided in the first mould impression 16 via the nozzle 34, in particular the cavity 23A. In the cavity 23B, a piston body 5 formed during a preceding cycle is already present. 30 WO 3004/035289 PC7BE2fl03/000}57 In the second mould impression 17 is simultaneously injected a second plastic via the noazle 35, whereby this plastic not only fills the cavities 26 and 27, but also the excavation 9 of the piston body 5 which is presented 5 against it and which is present in the cavity 23B. After the piston body 5 in the mould impression 16 and the plunger body 3 in the mould impression 17 have cured sufficiently, the mould is opened according to the 10 direction Tl, as represented in figure 5, whereby the protruding part 25 of the mould part 12 is pulled out of the excavation 9 of the piston body 5, while the latter is retained in a manner which is not represented in the figures. As the piston body 5 is made of supple plastic 15 and is elastically bendable, the protruding part 25 can be pulled loose with its edge 25B from behind the supple edge 10 without any problem. Possibly, means which are not represented can be provided 20 which hold the piston body 5 in the mould part 13 while the part 25 is being pulled out of the excavation 9, in order to prevent the piston body 5 from coming out of the mould part 13 as well. Further, use can be made of a folding core 25, either or not Combined with such means, such that 25 when, the mould concerned is opened, no or practically no tensile forces will be exerted on the piston body 5. Figure 6 shows how the mould part 13 is moved according to arrow T2, namely parallel to the support 22, as a result of 30 which the piston body 5 is pulled out of the cavity 23B of WO 2004/35289 PCT/BE2003/000157 -21- the mould part 13, as this piston body 5 is stuck behind the collar 7 of the plunger body 4 with its collar 10 - After the plunger 3 has been ejected from the maould, as 5 represented by means of a dot and dash line in figure 6, the mould part 13 is pulled out according to arrow 13 and then rotated over 90° in the sense of rotation R by means of the indexing mechanism 32, as represented in figure 7. 10 Figure 8 shows the composed mould after the mould part 13 has first been provided against the support 22 according to arrow T3. Finally, the mould is closed again according to arrows T2 15 and Tl, after which a new piston body 5 and a new plunger body 4 are formed, in the maould impressions 16 and L7 respectively, by injecting plastic- Figures 9 and 10 represent a second preferred embodiment of! 20 the device according to the invention, whereby the second mould part 13 has two cavities 23E and 23F, and this mould part 13 can he rotated along a tilted shaft 33A -which extends at an angle of 45° in relation to the longitudinal axes of the cavities 23E and 23F- 25 The use and working of this embodiment is analogous to that of the first embodiment, with as a sole difference that the mould part 13 is rotated in another manner. 30 It is clear that in both embodiments, the leading idea of the method of the invention is applied, i.e. that a piston WO 2004/035289 PCT/BE2003/000157 -22- body 5 is injected first, and that the plunger body 4 is subsequently injected against the latter. As represented, the piston body 5 and the plunger body 4 5 are preferably formed in one and the same direction. It is clear, however, that this does not exclude that, according to a variant, the piston bodies 5 could be formed in a first device, could be removed from this device and then be provided in a second device to there inject the plunger 10 body 4 against it. In order to keep the formed piston bodies 5 with some resisting force in the mould impression 16 concerned, the side walls can possibly be made with a light counter draft. 25 Instead of forming a connection with parts meshing behind one another, such as the collars 7 and 10, it is also possible to mainly or even exclusively base the connection on the adhesive force between both plastics. In this case, 20 it is possible to work with, a simple excavation. 9 in the piston body 5, which has no inwardly directed part, and the plunger body 4 can be simply made with a part reaching into the excavation 9, 25 As mentioned in the introduction, the invention also concerns embodiments whereby only a part of the plunger 3 is formed in the above-mentioned injection moulding cycles, in particular a part 36 which, as represented in figure 11, consists of the piston body 5 and a part 37 of the plunger 30 body 4, whereby this part 37 has the shape of an insert and WO 2004/035289 PCT/BE2003/000157 -23- is made such that it can be coupled to a second part 38 of the plunger body 4 to be produced separately. The parts 37 and 38 hereby comprise coupling means which 5 make it possible for these parts to be connected. In the embodiment of figure 1, these coupling means are formed of threaded parts 39 and 40, which make it possible for the parts 37 and 38 to be connected, as represented in figure 12. 10 Figure 13 shows that the part 36 can be realised in an almost similar manner as the plungers 3 in the device 11 of figure 4, The only difference consists in that the shape of the mould, parts concerned have to be adjusted to the 15 shape of the part 37 instead of to the shape of the entire plunger body 4. Figure 13 shows, consistent with figure 4, a device 11 in which the piston body 5 is each, time injected first, and 20 subsequently the accompanying part 37 . The above-mentioned coupling means between the parts 37 and 38 can be made in different shapes. Figure 14, for example, shows a variant with coupling parts 41-42 which 25 allow for a snap—in connection. Figure 15 shows a variant whereby the part 37 is provided with a threaded part 43 with internal screw thread, and the part 38 is provided with a threaded part 44 with outside thread. 30 Figures 16 and 17 represent a special embodimdent of a syringe 1 for medical purposes according to the invention. WO 2004/0335289 PCT/BE20O3/000157 24 This syringe 1 comprises at least a cylinder body or a cylinder 2 with an outlet 45 which is mainly formed of a narrowed outlet part 46 onto which can be fixed, for example, a hollow needle 47 or a catheter which is not 5 represented, as well as a plunger 3 working in conjunction with the cylinder body 2 which is provided with a plunger body 4 and a. piston body 5, What is special hereby is that. the plunger 3 has an accessory, in this case a part 48 which protrudes frontally from the front side of the piston 10 body 5 and which, as represented in figure 17, can penetrate at least partially in the above-mentioned outlet part 46, whereby this part 48 is formed of a material which differs from the material of the piston body 5, and which preferably consists of a plastic which is harder than the 15 material out of which the piston body 5 is formed. In the example of figures 16 and 17, the part 46 is made in one piece with the plunger body 4. According to a variant which is not represented, it could also be made in one 20 piece with a part 37 in the shape of a insert. The part 48 makes it possible to restrict the amount of liquid which remains in the syringe 1 when the syringe is used, after the plunger 3 has been entirely pressed in, to 25 a minimum, which is of major importance in the case of very expensive medical preparations. Figure 18 represents a device 11 with which the plungers 3 of the syringes 1 in figures 16-17 can be realised, for 30 example, which device, except for the use of mould parts WO 2004/035289 PCT/BE 2003/000157 -27- CLAIMS. 5 1. Method for manufacturing plungers for medical syringes, whereby such a plunger (3) consists of at least two parts, namely a longitudinal plunger body (4) made of plastic and a piston body (5) provided at the front end of the plunger body (4) which consists of a plastic which is softer than 10 the plastic of the plunger body (4), characterised in that such a plunger (3), or at least a part (36) thereof, is formed by first manufacturing the piston body (5} and then the plunger body (4), or at least a part (37) of this plunger body (4), by means of injection moulding, whereby 15 the plunger body (4), or the above-mentioned part (37) thereof, is injected against the piston body (5) WHICH PISTON 3024(5) is formed such that the front side and side 20 wall thereof are free of any flash lines and/or, such that the front side and side wall thereof are free of gate points for the plastic, 2. Method according to claim 1 or 2, characterised in that 25 the piston body (5) and the plunger body (4), or the aforesaid part (37) thereof, are connected by the sole adhesion between the plastics out of which they are made, in particular without any meshing parts, counter drafts or the like being realised thereby. 30 WO 200435289 PCT/BE2003/000157 3 Method according to claim 1 or 2 , characterised in that at least one inwardly directed part, such as a collar (10) , a part defining a counter draft or the like, is formed on the piston body (5) , as use is made during the injection 5 moulding of a mould part (12) with a protruding part (25) in which one or several recesses (25A) are laterally provided and/or a protruding part having one side to form the aforesaid counter draft, whereby, as the above- mentioned mould part (12) is removed from the piston body 10 (5) , use is made of the elastic flexibility of the material of" this piston body (5) , in order to pull the protruding part {25) from the formed piston body {5) . 4 Method according to any of the preceding claims, 15 characterised in that the plastic for forming the piston body (5) is provided in the mould impression (15) concerned via the back side of the piston body (5) to be formed. 5 Method according to any of the preceding claims, 20 characterised in that the piston body (5) is formed in a first mould impression (16), after which this piston body (5), while it is still being held in the first mould impression (16) or a part thereof is presented to a second mould impression (17) in which the plunger body (4) , or the 25 above-mentioned part (37) thereof, is then injected against the piston body (5) by means of injection moulding, whereby mould, impressions (16-17) ate applied having such a shape that the obtained plunger body (4) or the above-mentioned part (37) thereof and the piston body (5) are connected to 30 one another thanks to their shape and/or thanks to the adhesion between the plastics. WO 2004/035289 PCT/BE2003/000157 -29- 6 Method according to claim 6, characterised in that, while the plunger body (4) or the above-mentioned part (37) thereof is formed such that it connects to the piston body 5 (5), a subsequent piston body (5) is simultaneously being formed by means of the same nozzle (34) with which the first piston body (5) is realised, but in another mould. impression. 10 7 Method according to any of the preceding claims, characterised in that the piston body (5) is formed in a mould with mould parts (12—13) whose partial surface mainly coincides with the rear side of the piston body (5) to be formed or extends parallel thereto, after which the mould 15 part (12) with the piston body (5) provided in it is presented against mould parts (14-15) in which the plunger body (4) or the aforesaid part (37) thereof is formed. 8 Method according to any of the preceding claims, 20 characterised in that when realising such a plunger (3) or a part (36) thereof, also an accessory is formed which is situated with at. least a part thereof on the front side of the piston body (5) , and which consists of a material which is different from the material of the piston body (5) 25 9 Method according to claim 9, characterised in that the material of the accessory consists of a plastic which is harder than the plastic out of which the piston body (5) is formed. 30 WO 2004/035289 PCT/BE2OO3/000157 -30- 10. Method according to claim 8 or 9 characterised in that the above-mentioned accessory consists of a part (48) which extends frontally from the front sids of the piston body (5) and which when the plunger (3) is situated in the 5 syringe (1)r can at least partially penetrate in the outlet (45) of the syringe (1) , in order to be able to optimally empty the syringe (1) . 11. Method according to any of claims 8 or 10, 10 characterised in that the aforesaid accessory consists of a part which makes it possible to create a passage between the front side and the rear side of the piston body (5) when emptying the syringe (1) in order to prevent the syringe (1) from being re-used. 15 12. Method according to any of claims 8 to 11, chracterised in that the above-mentioned accessory can be made in any of the following shapes: - as a part made in one piece with the plunger body 20 (4) of the above-mentioned part (37) thereof, and thus formed simultaneously with it during the injection moulding; - as a separate part provided on the front aide of the piston body (5) ; 25 - as a separate part provided on the front side of the piston body (5), whereby this part is injected against the material of the piston body (5) after this piston body (5) has been formed. 30 13. Method according to any of the preceding claims, characterised in that, in the case where only a part (37) WO 2004/035209 PCT/BE2003/000157 31 of the plunger body (4) is injected against the piston body (5) , this part (37) is made as an insert, which makes it possible to provide for a connection with the rest of the plunger body (4) at a later stage. 5 14. Method according to any of the preceding claims, characterised in that, instead of being used for anufacturing plungers (3) with a longitudinal plunger body (4), they are used for manufacturing plungers of the type 10 which is meant to be used in combination with a drive element, whereby such a plunger then mainly consists of a piston body (5) and a plunger part, whereby this plunger part is fit to co-operate with such a drive element. 15 15. Method for manufacturing plungers for medical syringes comprising at least a piston body (5) , characterised in that a part (48) is formed: at the height of the piston body (5) which protrudes frontally from the front side of the piston body (5) and which, when the plunger (3) is situated 20 in the syringe (1), can penetrate at least partially in the outlet (45) of the syringe (1) , whereby this part (48) is formed of a material which is different from, and preferably harder than the material of the piston body (5) f and whereby the piston body (5) on the one hand and the 25 aforesaid protruding part (48) on the other hand are injected against one another, whereby the above-mentioned part (48) Can either or not be made in one piece with a plunger body (4) belonging to the plunger (3) . 30 16. Device for applying the method according to any of claims 1 to 14, characterised in that it at least consists WO 2GIM/G352&? PCT7BE2003/000157 -32- of a number of mould parts Q2-13-14-15) defining at least a first mould impression (16) and a second mould impression (17) for forming the piston body (5) and the plunger body (4) respectively, or a part [37) of the plunger body (4) ; a 5 motion mechanism which, makes it possible to move the above- mentioned mould parts (12-13-14-15) in relation to one another and. to position them differently so that, in a first position, the piston body (5) can be injected, whereas in a second position, the plunger body (4) or the 10 aforesaid part (37) thereof can be injected against the piston body (5) ; and injection means to supply the piastic to be injected to the aforesaid mould impressions (12—13 — 14-151 respectively^ b/Me&~4^ /V 7W £fiP/t£J#t$ ?f&T /frfsrr&tf, 7#& 15 l£. Device according to claim yjr characterised ±n that the A ^ %£, first mould impression (16J is mainly situated in a single mould part (13) and in that the motion mechanism consists of a mechanism with which said first mould part (13) with the mould impression 20 between at least two positions, namely a first position whereby this mould impression (16) is mainly sealed and is connected to a nozzle (34) for injecting a first plastic on the one hand, and a. second position whereby this mould impression (16) connects , to the second mould impression 25 (17) and whereby the latter is connected to a nozzle (35) for injecting; a second plastic on the other hand. 18 Device according to claim JtfBt characterised in that it comprises two or several mould impressions fl6) for the 30 formation of" piston bodies (5) which are situated such that one of these mould impressions (16) can worJc in conjunction WO 2004/0352S9 PCT/BE2Mt3/tM -33- with the first nossls (34), while &n mould impressions (16) is simultaneously being presented to the second mould impression (17) , and in that the motion mechanism moves the first mould, impressions (16) in such a 5 manner that the fixst mould Impir&sszons (16) systematically and repeatedly presented to each time the first no2ale (34) and the second mould impression 19. Device according to any of claims 16 to 18, 10 characterised in that the motion mecnanisin is a rotating indexing mechanism {32)r whose axis of rotation (33-33A) has a direction which is different from the direction or directions of movement according to which the mould parts (12-13—14-15) which are required to form the aforesaid 15 mould impressions (16-17) open and close. 20 Device according to any of claims 16 to 19, characterised in that the injection means comprise two nozzles (34~35) for injecting two plastics respectively, 20 and in that both nozzles the same mould part or in one and the same whole, consisting of rigidly connected mould parts (12—14}. 21 Device according to any of claims 16 to 20 25 characterised in that the injection means convprise two nozzles (34-35), for injecting two plastics respectively, and in that both nozzles (34-35) open in parallel land areas of the mould parts (12-14) concerned* 30 22 Device according to any of claims 16 to 21 characterised in that the mould impressions (16—17) are WO 20a4/03i29 PCTYBE2OO3MIHU57 34 formed of mould parts (12-13-14-15) which together define three partial surfaces, in other words surfaces whose mould impressions (16-17) open and close, and in that these partial surfaces are mainly situated step-like in relation 5 to each other. 23 Device according to any of claims y? to ^5, characterised in that it consists of a composed mould, which mainly comprises three parts (18-19-20) which can be 10 mutually moved, a first part (IS) and a second part (19) respectively V7hich can be put against one another by means of a. translation movement, can be moved away from one another respectively/ and a thiard part (20) which can toe moved between at least two positions, namely a first 15 position in which this third part {20) at least co-operates with the first part (IS) in order to define the first mould impression (16) on the one handr and a second position in which a third part (20) at least co-operates with the first part (18) as well as the second part (19) in order to 20 define the mould impression (17) , such that the latter connects to the part of the plunger (3) formed in the first mould impression (16) , 24. Device according to claim 23, characterised in that the 25 third part (2 0) can be rotated and can also make a translation movement (T3) in relation to the first part (13J and the second part [19) in order to provide for the opening and sealing of the mould impressions (16-17) concerned * 30 WO 2004/O35289 PCT7BE2OO3/0QO157 -35- 25 Device according to claim 23 or 24, characterised in that the second part (19) and third part [20) are mounted on a common support {22}, such that they can be mutually moved, which support can be mutually moved in turn in 5 relation to the first part (IS), 26. Syringe far medical purposes, characterised in that it comprises a plunger of which at least a part has been realised according to the method of any of claims 1 to 16. 10 27 Syringe for medical purposes, comprising- at least a cylinder bocly {2) with an outlet (45J whicTn is fontted of a narrowed outlet part (AG) , as well as a plunger (3) working in conjunction with the cylinder body (2) which is provided 15 with a piston body {5} and. a plunger body (4) t characterised in that the plunger (3) comprises a part [4 8) which protrudes frontally from the front side of the piston body (5) and which can penetrate at least partially in ths above-mentioned outlet part (46) , whereby this part (48) is 20 formed of a material which is different from the material of the piston body (5>, and preferably consists of a plastic which is harder than the material out of which the piston body (5) is formed. 25 28 Syringe accordingto claim 27f characterised in ttiat the above-mentioned part (4S) which protrudes frontally from the front side of the piston body [5) is made according to either of the following two possibilities: - as a part made in one piece with the plunger body (4) or 30 wade in one piece with a part (37) of this plunger body (4); WO JWWBJ5289 PCT7BE2O03/000157 -36- - as A separate part situated on the piston body (5) . Method for manufacturing plungers for medical syringes, whereby such a plunger: (3) consists of at least two parts namely a longitudinal plunger body (4) made of plustic and a piston body (5) Provided at the from end of the plunger body (4) which consists of a plastic which is softer than the plastic of the plunger body (4), charecterised in that such a plunger (3), or at ieast a part (36) thereof, is formed by first manufacturing the piston body (5) and then the plunger body (4). of at least a part (37) of this plunger body (4), by means of injection moulding , whereby the piunger body (4), of the above-mentioned part (37) thereofo, is injected against the piston body (5).

Full Text

-1-
Method_and device _for manufacturing plungers for medical
syringes/ plungers obtained thereby, as well as a syringe
5 for medical purposes.
The present invention concerns methods for manufacturing
plungers for medical syringes, as well as devices applying
such method and plungers obtained according to said method.
10 Further, it also concerns different embodiments of
syringes, in particular syringes with special embodiments
of plungers,
In particular, the invention concerns a method for
15 manufacturing such, plungers out of plastic.
By syringes should be understood in this case all
recipients provided, with a piston or plunger with which
liquid can be sucked up in the recipient and/or can be
20 pressed out of the recipient. Examples thereof are
injection syringes and dose syringes.
The above-mentioned plungers, which are designed to be
pushed in a slidable manner in a usually cylindrical
25 recipient, as is known consist of a longitudinal plunger
body upon which is fixed a piston body at the front in the
shape of a head. The plunger body is usually made of a
relatively hard plastic, whereas the piston body is made of
a softer material which guarantees a good sealing against
30 the cylinder wall of the syringe.

WO 2004/035289 P€T/BE2003/000157
-2-
The above-mentioned parts, the plunger body on the one hand
and the piston body on the other hand, are traditionally
made entirely separately, to be subsequently assembled,
either manually or by means of an assembly machine.
5
The two aforesaid parts of the known plungers are
traditionally attached to each other by means of a sort of
snap-in system, in particular by means of collars meshing
behind one another, such that the piston body can be
10 pressed down on the far end of the plunger body.
As, according to the known technique, the two parts of a
plunger are manufactured separately and have to be
subsequently assembled, this technique is relatively
15 complicated, time-consuming and expensive. There is also a
chance that the parts do not perfectly mesh during the
assembly, so that problems may arise at a later stage, when
the plunger is pushed in the cylindrical body of the
syringe or the like.
20
According to newer techniques, the two parts of the plunger
are provided onto each other in a single injection-moulding
machine, so that no separate mechanical mounting is
required and the above-mentioned disadvantages are
25 excluded.
A first example thereof is known from EP 1.099.449. The
plunges body is hereby first injection-moulded out of hard
plastic in a mould impression, after which a piston body
30 made of a softer plastic is then formed on the plunger body
by enlarging said mould impression near the front end of

WO 2004/035289 PCT/BE2003/00157
-3-
the formed plunger body and by then injecting the softer
plastic in the space which has thus become available.
In order to be able to enlarge the above-mentioned mould.
5. impression, the mould is provided with a sliding part. A
disadvantage of the use of such a sliding part consists in
that a sub edge may be created on the front side of the
formed piston body at the transition between said sliding
part and the surrounding mould parts , which is undersirable
10 in medical applications since, at the height of said sub
edge, material particles may come off and thus end in
the reservoir of the syringe, and thus also in the medical
liquid to be injected.
15 The injection of the plastic For forming the piston body is
not simple either in this case. According to a first known
possibility, the plastic may be injected laterally, which
results in gate points being created in the side wall of
the piston body, which is not desirable in practice.
20 According to a second known possibility, the injection
takes place through a supply duct formed, in the plunger
body. This prevents the formation of gate points on the
front side or side wall of the piston body, but a
disadvantage consists in that rather complex additional
25 means are required to form such a supply duct through the
plunger body.
A second example is known from US 5.902.276, whereby a
plunger body is formed in a first mould and a thin layer of
30 soft plastic is subsequently provided in a second mould
over the front end of said plunger body, in order to thus

WO 2004/035289 PCT/BE2003/O00157
-4-
realise a piston body. The soft plastic is hereby injected
via the back side of the piston body to be formed.
However, a disadvantage hereby is that the presence of the
already formed plunger body leaves little room to provide a
5 nozzle in an efficient manner. Also, several nozzles per
piston body have to be provided in order to make sure that
the plastic spreads sufficiently through the mould
impression. Also, the devices required to this end are
relatively complex.
10
The present invention in general aims a method for
manufacturing plungers for medical syringes out of plastic
which is new and offers several advantages as such, such as
for example an efficient manufacturing. Also, it aims a
15 method which makes it possible to exclude the disadvantages
of the above-mentioned known methods, at least when certain
preferred embodiments are applied.
To this end, according to a first aspect, it concerns
20 method for manufacturing plungers for medical syringes,
whereby such a plunger consists of at least two parts,
namely a longitudinal plunger body made of plastic and a
piston body provided, at the front end of the plunger body
which consists of a plastic which is softer than the
25 plastic of the plunger body, characterised in that such a
plunger is formed by first manufacturing the piston body
and then the plunger body by means of injection moulding,
whereby the plunger body is injected against the piston,
body.
30

WO 2004/035289 PCT/BE2003/000157
-5-
Since, of each plunger the piston body is formed first, and
then the plunger body, the liquid plastic for forming the
plunger body is pressed against the supple plastic of the
already formed priston body, as a result of which this
5 supple plastic is pressed in somewhat elastically, so that
a particularly tight fit of the piston body on the plunger
body is obtained, in the end.
By first forming the piston body and then the plunger body,
10 this also offers the advantage that the plastic for the
piston body can be easily provided via the side of the
mould Impression which is meant to form the back side of
the piston body. In this manner, the formation of flash
lines and gate points on the piston body can be easily
15 excluded without any relatively complicated constructions
for the supply of plastic being required Hence, the
piston body will preferably be formed such that its front
side and side wall are entirely free of flash lines and/or
gate points for the plastic.
20
In particular, the piston body is preferably formed in a
mould, impression whose walls, which connect to the front
side and the side wall of the piston body to be formed, are
part of one and the same undivided mould part.
25
The plastic for forming the piston body is preferably
provided via the back side of the piston body to be formed
in the mould impression concerned, possibly centrally, such
that an even spread of the plastic in the mould impression
30 is promoted. Moreover/ a single nozzle may then be
sufficient for the infection of said plastic.

WO 2004-035289 PCT/BE2003/000157
-6-
As the piston body is formed first and this piston body
consists of an elastically bendable material, this offers
the advantage that the piston body, even when it has an
5 inwardly directed collar and/or a part defining a counter
draft, can be easily taken out of the mould, simply by
pulling the mould part concerned loose, from. behind said
collar or out of the counter draft.
10 What precedes does not exclude, however, that according to
another preferred embodiment, the piston body and the
plunger body are connected to each other merely by the
adhesion between the plastics out of which they are made,
in particular without any parts meshing behind each other,.
15 counter drafts and the like thereby being realised. For,
by making use of suitable plastics, for example the types
of plastic mentioned hereafter, it is possible to obtain an
adhesion which is sufficiently large without any explicit
mechanical lock in the shape of meshing parts being
20 required. This offers as an advantage that the mould for
forming the piston body can be opened effortlessly, without
the formed piston body coming out of the mould impression
in an unwanted manner.
25 According to yet another possibility, use can also be made
of a folding core, which makes it possible to form inwardly
directed parts on the piston body. By folding the core
before it is removed from the formed piston body, it can
subsequently be removed from said piston body without any
30 tensile force being exerted on the piston body.

WO 2004/035289 PCT/BE2003/000157
According to the most preferred embodiment, the above-
mentioned method is characterised in that the piston body
is formed in a first mould impression, after which, said
piston body, while it is still being held in the first
5 mould impression or a part thereof, is presented to a
second mould impression in which the plunger body is then
injected against the piston body by means of injection
moulding, whereby mould impressions are applied having such
a shape that the obtained plunger body and piston body are
10 connected to one another thanks to their shape and/or
thanks to the adhesion between the used plastics. By
making use of two mould impressions instead of one mould
impression which is locally enlarged after a first part has
been moulded, this offers the advantage that the mould
15 parts used thereby for forming the piston body and the
plunger body respectively can be optimised individually.
preferably, the method is also characterised in that, while
a plunger body is being formed connected to a piston body,
20 a subsequent piston body is formed simultaneously by means
ox the same nozzle with. Which the first piston body is
realised, but in another mould impression. This allows for
an efficient production whereby, during each injection
cycle, a piston body as well as a plunger body are formed.
25
The piston body is preferably formed in a mould with mould
parts whose partial surface mainly coincides with the back
side Of the piston body to be formed or extends parallel
thereto. This makes it possible, after the piston body has
30 been formed/ to simply present the mould, part in which the
piston body is provided with the side defining the above-

WO 2004/035289 PCT/BE2003/000157
-8-
mentioned partial surface against the mould parts in which
the plunger body is formed, without any complex movements
of the mould parts being required.
5 The piston body is preferably made of a thermoplastic
elastomer, while the plunger body is made of polypropylene
or the like -
It should be noted that the invention also concerns
10 embodiments whereby not the entire plunger body is injected
against the piston body, but merely a part of this plunger
body is injected against the piston body, after which the
obtained part, formed of the aforesaid part and the piston
body, are connected afterwards to a second, individually
15 manufactured part of the plunger body, for example via a
mechanical coupling between both parts. The above-
as rationed part which, is injected against the piston body is
preferably made in the shape of an insert which makes it
possible to make a connection to the rest of the plunger
20 body at a later stage, as mentioned above. By an insert is
meant that the above-mentioned part is only limited in size
and has been mainly designed to form a connection with the
piston body on the one hand, by means of embedment, and to
form a part which can be easily connected to the rest of
25 the plunger body as such on the other hand, for example by
means of a mechanical coupling.
According to a special embodiment, when realising such a
plunger or a part thereof, also an accessory is formed
30 situated on the front side of the piston body, and which
consists of a material which is different from the material

WO 2OO4/O35289 PCT/BE2003/000157
of the piston body. Such an accessory can be of any nature
whatsoever. A number of examples will be illustrated
hereafter. As such an accessory is made of a separate
material, this offers the advantage that its material
5 selection can be optimised as a function of the purpose of
such an accessory. The material of the accessory will
preferably consist of a plastic which is harder than the
plastic out of which the piston body is formed.
10 By an 'accessory which is situated on the front side of the
piston body' is meant every part which is accessible via
the front side of the piston body.
According to a first possibility, the above-mentioned.
15 accessory consists of a part which extends frontally from
the front side of the piston body and which, when the
plunger is situated in the syringe, can at least partially
penetrate in the outlet of the syringe, which makes it
possible to optimally empty the syringe. The use of such a
20 protruding part is known as such, but not that it is made
of a different material, in particular another plastic than
the one out of which the piston body is formed. By making
use of different materials is thus obtained that
independent material selections can be made whereby, when
25 the material of the piston body is selected, an
optimisation of the sealing can be aimed at, whereas when
the material of the protruding part is selected, an
optimisation can be aimed at for this part in order to make
it function optionally. Thus, for example, by selecting a
30 harder plastic, the protruding part can be made rattier

WO 2004/035289 PCT/BE20O3/000157
-10-
rigid, as a result of which it cannot bend and. will not be
situated exactly in front of the outlet.
According to another possibility, the above-mentioned
5 accessory consists of a part which makes it possible to
create a passage between the front side and the rear side
of the piston body when emptying the syringe, in order to
prevent "the syringe being re-used, as a result of which,
what is called a safety syringe is obtained-
1O
The above—mentioned accessory is preferably made In one; of-
the following shapes:
— as a part which is made in one piece with the plunger
body or a part thereof, and which is thus formed
15 simultaneously with the latter during the injection
moulding, which offers the advantage that the
accessory always remains perfectly aligned, for
example remains axially aligned, and that no separate
injection moulding cycle is required to form the
20 accessory;
— as a separate part provided on the front side of the
piston body;
— as a separate part provided on the front side of the
piston body, whereby this part is injected, against the
25 material of the piston body after the piston body has
been formed, which offers the advantage that no liquid
can leak away between both plastics.
It should be noted that the invention can also be used for
30 realising short plungers, in particular plungers of the
type designed to co-operate with a drive element. In

WO 2004/035289 PCT/BE2003/000l57
-11-
practice, such plungers are used for example in syringes or
the like to slowly administer medical substances to a
patient, in a dosed manner by means of a pump. Such a
syringe is then connected to the patient via a catheter.
5 The plunger is connected to an automatically driven drive
element of the pump, which moves very slowly when in use.
Also, taking info account what precedes, the present
invention, according to a second aspect, provides for a
10. method as described above, characterised in that, instead
o£ being used to manufacture plungers with a longitudinal
plunger body, it is used to manufacture plungers of the
type which is meant to be used in combination with a drive
element, whereby such a plunger then mainly consists of a
15 piston body and a plunger part, whereby this plunger; part
is fit to co-operate with, such a drive element.
It should also be noted that the characteristic in that a
part is formed at the height of the piston body which
20 protrudes frontally from the front side, of the piston body
and which, when the plunger is situated in the syringe, can
penetrate at least partially in the outlet of the syringe,
whereby this part and the piston body are formed of
materials, in particular plastics which are injected
25 against one another, is advantageous when the piston body
is moulded first and then the protruding part, as well as
when the protruding part is moulded first and then the
piston body. Fox, in both cases, the above-mentioned
advantages remain applicable.
30

WO 2004/035289 PCT/BE2003/000157
-12-
Taking into account what precedes, the present invention,
according to a third aspect, also provides for a method for
manufacturing plungers for medical syringes comprising aL
least a piston body, characterised in that, at the piston
5 body, a part is formed which protrudes frontally from the
front side of the piston body, and which, when the plunger
is situated in the syringe, can penetrate at least
partially in the outlet of the syringe, whereby this part
is formed of a material which differs from, and is
10 preferably harder than the material of the piston body, and
wthereby the piston body on the one hand and said, protruding
part on the other hand are injected against one another,
whereby the above-mentioned part is either or not made in
one piece with a pLunger body belonging to the plunger.
15
According to a fourth aspect, the invention concerns a
device for the application of the method according to the
first and second aspect, characterised in that it at least
consists of a number of mould parts which at least define a
20 first mould impression and a second mould impression to
form the above-mentioned piston body and the above-
mentioned plunger body respectively, or a Part of this
plunger body; a motion mechanism which makes it possible to
move the above-mentioned mould parts in relation to one
25 another and to position them differently so that, in a
first position, a piston body can be injected, whereas in a
second position, the plunger body or the aforesaid part
thereof can be injected, against the piston body; and
injection means to supply the plastic to be injected to the
30 aforesaid mould impressions respectively.

WO 2004/035289 PCT/BE2003/000157
-13-
According to the invention, the present device may have
some more special additional characteristics, as explained
in the following description and as described in the
accompanying claims, which characteristics can be either or
5 not combined.
It is clear that also devices which make it possible to
realise the methods according to the aforesaid third, aspect
fall within the scope of the invention. Its construction,
10 taking the description of the method as a basis. Ijes
within the scope of the knowledge of any craftsman.
Naturally, the invention also concerns plungers, as well as
parts of plungers, made according to the preceding method,
15 as well as syringes that are equipped with such plungers.
Finally, it should be noted that also the fact that the
above-mentioned part protruding from the piston body
consists of another material than the piston body itself,
20 is advantageous as such and offers several of the above-
mentioned advantages, irrespective of whether this part has
been formed by forming it together with the piston body in
two successive injection moulding cycles, or in any other
way whatsoever, for example made separately to be
25 subsequently connected to the piston body in a mechanical
manner.
Taking into account what precedes, the invention also
concerns a syringe for medical purposes, according to a
30 fifth aspect, comprising at least a cylinder body with an
outlet which is formed of a narrowed outlet part, as well

WO 2004/035289 PCT/BE2003/000l57
-14-
as a plunger working in conjunction with the cylinder body
which is provided with a piston body and a plunger body,
characterised in that the plunger comprises a part which
protrudes frontally from tne front side of the piston body
5 and which can penetrate at least partially in the above-
mentioned outlet part, whereby this part is formed of a
material which is different from the material of the piston
body, and. preferably consists of a plastic which is harder
than the material out of which the piston body is formed.
10
In this case also, the part which protrudes frontally from
the front side of the piston body, can be made according to
either of the following two possibilities:
- as a part which, is made in one piece with the plunger
15 body or made in one piece with a part of this plunger
body
- as a separate part provided at the piston body.
In order to better explain the characteristics of the
20 invention, the following preferred embodiments are
described, as an example only without being limitative in
any way, with reference to the accompanying drawings, in
which:
25 figure 1 represents a syringe which is equipped with a
plunger made according to the method of the invention;
figure 2 represents the plunger of the syringe from
figure 1 in perspective;
figure 3 represents a section according to line III-
30 III in figure 2;

WO 2004/035289 PCT/BE20O3/000157
figures 4 to 8 represent a device according to the
invention in different stages of the method;
figures 9 and 10 represent a variant of the embodiment
of a device according to the invention, when closed
5 and when opened respectively;
figures 11 and 12 represent a plunger body as
dismounted, and as mounted respectively, which has been
realised according to a method of the invention;
figure 13 schematically represents how the part which
10 is indicated by F13 in figure 11 can be realised by
means of successive injection mounting cycles;
figures 14 and 15 represent two variants of a plunger-
body according to the invention, for a view similar to
that in figure 11;
15 figures 16 and 17 represent a section of a syringe
according to the invention, for two different
positions of the plunger body;
figure 18 shows how the plunger bodies for forming
syringes according to figures 16 and 17 can be formed
20 by successive injection moulding cycles;
figure 19 shows another special embodiment of a
syringe according to the invention.
A plastic syringe 1, as is used for medical applications,
25 mainly consists, as is represented in figure 1, of a
recipient, in this case a cylinder 2 and a plunger 3.
As is represented in greater detail in figures 2 and 3, the
plunger 3 is composed of a plunger body 4 and a piston bociy
30 5, which in the given embodiment have such a shape that
they mesh and as stich remain coupled.

WO 2004/1135289 PCT/BE2003/000I57
-16-
As is represented, the plunger body 4, which normally
consists of a relatively hard. plastic, for example
polypropylener preferably has a cross-shaped shaft 6
5 provided- with a collar 7 on one far end.
The above-mentioned piston body 5, which is preferably made
of a soft material, such as thermoplastic elastomer, is
made in the shape of a head and is provided with an
10 excavation 9 on the rear side 8 which is partially
confined by an inwardly directed collar 10, which co-
operates with the collar 7 of the plunger body 4 .
The invention aims a method and a device for manufacturing
15 plungers 3, or at least plungers of a srmilar type, in
other words plungers 3 which consist of a plunger body 4
and a piston body 5 of different plastics. In order to
illustrate the method, the construction of a preferred
embodiment of a device 11 applied thereby, in particular a
20 combined injection mould, is first described hereafter by
means of figures 4 to 6.
The device 11 comprises a number of mould parts, in this
case four, 12-13-14-15 respectively, defining `first' mould.
25 impressions 16 and a 'second' mould impression 17, for
forming a first part of the plunger 3, namely the pistor;
body 5, and a second part of the plunger 3, namely the
plunger body 4 respectively.
30 The mould parts 12-13-14-15 together form three parts. 18-
13-20 Which can be mutually moved.

WO 2004/1135289 PCT/BE2003/000I57
-17-
The first part 18 is formed of the mould parts 12 and 14
which are mounted on a common support 21 which is
preferably fixed.
5
The second part 19 is formed of the mould part 15 which is
mounted on a support 22. This second part 19 can make a
translation movement T1 in relation to the first part 18.
10 The third part 20 is formed of the mould part 13, which is
mainly square and movable/ in particular is provided in an
extending and rotatable manner on the support 22.
The first mould impressions 16 are formed of cavities 23A-
15 23B-23C-23D provided on the surface of the mould part 13,
in this case on each of the four sides thereof
respectively, as well as of the wall part 24 of the mould
part 12 with which the cavity which is turned towards this
wall part 24 can be sealed. On the wall part 24 is
20 provided a protruding part 25 which is designed to form the
excavation 9, and which is provided, with a recess 25A which
is confined by a collar 25B.
Hereby is obtained that the partial surface between the
25 mould parts 12 and 13 coincides with the rear side 8 of the
piston body 5 to be formed,
By means of the translation movement T1, the mould
impression 16 can be opened, sealed respectively.
30

WO 2004/1135289 PCT/BE2003/000I57
-18-
The second mould impression 17 is mainly formed of the
cavities 26 and 27 provided the the surface of the mould
parts 14 and 15 respectively. These cavities 26 and 27
hereby open into sides 28 and 29 as well as into sides 30
5 and 31 standing at right angles thereto.
Further, these cavities 26 and 27 are situated such, that
the mould impression 17 formed thereby, when the whole is
closed, connects to the cavity 23B._ The longitudinal axes
10 of the mould impression 17 and the mould impression 16, in
particular the cavity 23Bf are tvareby situated in each
other's prolongation.
The mould parts 14 and 15 can also be moved towards one
15 another and away from one another the means of the
translation movement Tl. Further, the mould part 13 can
make a translation movement T2 as well as a rotational
movement R.
20 In order to realise the movements Tl, T2 and R, the device
11 is provided with a motion mechanism, consisting of
drives which can move the three parts 18-19-20 in relation
to one another, as will be further described, which are not
represented for clarity' s sake. It should be poted that
25 the mould part 13 can also make a translation movement 13
in relation to the support 22 which has to make it possible
for the mould part 13 to freely rotate.
For the rotation, use is made of a rotating indexing
30 mechanism 32, whose axis of rotation 33 has a direction
which is different from the direction or directions of

WO 2004/035289 PCT/BE2003/000157
-19 -
movement according to which the mould parts 12-13 and 14-15
open and close.
It should be noted that, as represented in the figures, the
5 mould, parts 12-13-14-15 together- define three partial
surfaces in other words surfaces whose composed mould
opens and closes, which are situated in a stepped manner in
relation to one another. This stepped construction allows
for a compact construction.
10
Further, the device 11 comprises injection means for
supplying the plastic to be injected to the aforesaid, mould
impressions respectively which consist of nozzles 33—35
provided in the fixed part 18 and which preferably have
15 parallel longitudinal axes, and which also open in parallel
partial surfaces.
Moreover, the nozzle 34 extends centrally through the
protrvitiing part 25
20
The working of the device 11, as well as the accompanying
method, is described hereafter by means of the different
positions represented in figures 4 to 8.
25 Figure 4 shows the composed mould when closed. A first
plastic is hereby provided in the first mould impression 16
via the nozzle 34, in particular the cavity 23A. In the
cavity 23B, a piston body 5 formed during a preceding cycle
is already present.
30

WO 3004/035289 PC*7BE2fl03/000}57
In the second mould impression 17 is simultaneously
injected a second plastic via the noazle 35, whereby this
plastic not only fills the cavities 26 and 27, but also the
excavation 9 of the piston body 5 which is presented
5 against it and which is present in the cavity 23B.
After the piston body 5 in the mould impression 16 and the
plunger body 3 in the mould impression 17 have cured
sufficiently, the mould is opened according to the
10 direction Tl, as represented in figure 5, whereby the
protruding part 25 of the mould part 12 is pulled out of
the excavation 9 of the piston body 5, while the latter is
retained in a manner which is not represented in the
figures. As the piston body 5 is made of supple plastic
15 and is elastically bendable, the protruding part 25 can be
pulled loose with its edge 25B from behind the supple edge
10 without any problem.
Possibly, means which are not represented can be provided
20 which hold the piston body 5 in the mould part 13 while the
part 25 is being pulled out of the excavation 9, in order
to prevent the piston body 5 from coming out of the mould
part 13 as well. Further, use can be made of a folding
core 25, either or not Combined with such means, such that
25 when, the mould concerned is opened, no or practically no
tensile forces will be exerted on the piston body 5.
Figure 6 shows how the mould part 13 is moved according to
arrow T2, namely parallel to the support 22, as a result of
30 which the piston body 5 is pulled out of the cavity 23B of

WO 2004/35289 PCT/BE2003/000157
-21-
the mould part 13, as this piston body 5 is stuck behind
the collar 7 of the plunger body 4 with its collar 10 -
After the plunger 3 has been ejected from the maould, as
5 represented by means of a dot and dash line in figure 6,
the mould part 13 is pulled out according to arrow 13 and
then rotated over 90° in the sense of rotation R by means
of the indexing mechanism 32, as represented in figure 7.
10 Figure 8 shows the composed mould after the mould part 13
has first been provided against the support 22 according to
arrow T3.
Finally, the mould is closed again according to arrows T2
15 and Tl, after which a new piston body 5 and a new plunger
body 4 are formed, in the maould impressions 16 and L7
respectively, by injecting plastic-
Figures 9 and 10 represent a second preferred embodiment of!
20 the device according to the invention, whereby the second
mould part 13 has two cavities 23E and 23F, and this mould
part 13 can he rotated along a tilted shaft 33A -which
extends at an angle of 45° in relation to the longitudinal
axes of the cavities 23E and 23F-
25
The use and working of this embodiment is analogous to that
of the first embodiment, with as a sole difference that the
mould part 13 is rotated in another manner.
30 It is clear that in both embodiments, the leading idea of
the method of the invention is applied, i.e. that a piston

WO 2004/035289 PCT/BE2003/000157
-22-
body 5 is injected first, and that the plunger body 4 is
subsequently injected against the latter.
As represented, the piston body 5 and the plunger body 4
5 are preferably formed in one and the same direction. It is
clear, however, that this does not exclude that, according
to a variant, the piston bodies 5 could be formed in a
first device, could be removed from this device and then be
provided in a second device to there inject the plunger
10 body 4 against it.
In order to keep the formed piston bodies 5 with some
resisting force in the mould impression 16 concerned, the
side walls can possibly be made with a light counter draft.
25
Instead of forming a connection with parts meshing behind
one another, such as the collars 7 and 10, it is also
possible to mainly or even exclusively base the connection
on the adhesive force between both plastics. In this case,
20 it is possible to work with, a simple excavation. 9 in the
piston body 5, which has no inwardly directed part, and the
plunger body 4 can be simply made with a part reaching into
the excavation 9,
25 As mentioned in the introduction, the invention also
concerns embodiments whereby only a part of the plunger 3
is formed in the above-mentioned injection moulding cycles,
in particular a part 36 which, as represented in figure 11,
consists of the piston body 5 and a part 37 of the plunger
30 body 4, whereby this part 37 has the shape of an insert and

WO 2004/035289 PCT/BE2003/000157
-23-
is made such that it can be coupled to a second part 38 of
the plunger body 4 to be produced separately.
The parts 37 and 38 hereby comprise coupling means which
5 make it possible for these parts to be connected. In the
embodiment of figure 1, these coupling means are formed of
threaded parts 39 and 40, which make it possible for the
parts 37 and 38 to be connected, as represented in figure
12.
10
Figure 13 shows that the part 36 can be realised in an
almost similar manner as the plungers 3 in the device 11 of
figure 4, The only difference consists in that the shape
of the mould, parts concerned have to be adjusted to the
15 shape of the part 37 instead of to the shape of the entire
plunger body 4.
Figure 13 shows, consistent with figure 4, a device 11 in
which the piston body 5 is each, time injected first, and
20 subsequently the accompanying part 37 .
The above-mentioned coupling means between the parts 37 and
38 can be made in different shapes. Figure 14, for
example, shows a variant with coupling parts 41-42 which
25 allow for a snap—in connection. Figure 15 shows a variant
whereby the part 37 is provided with a threaded part 43
with internal screw thread, and the part 38 is provided
with a threaded part 44 with outside thread.
30 Figures 16 and 17 represent a special embodimdent of a
syringe 1 for medical purposes according to the invention.

WO 2004/0335289 PCT/BE20O3/000157
24
This syringe 1 comprises at least a cylinder body or a
cylinder 2 with an outlet 45 which is mainly formed of a
narrowed outlet part 46 onto which can be fixed, for
example, a hollow needle 47 or a catheter which is not
5 represented, as well as a plunger 3 working in conjunction
with the cylinder body 2 which is provided with a plunger
body 4 and a. piston body 5, What is special hereby is that.
the plunger 3 has an accessory, in this case a part 48
which protrudes frontally from the front side of the piston
10 body 5 and which, as represented in figure 17, can
penetrate at least partially in the above-mentioned outlet
part 46, whereby this part 48 is formed of a material which
differs from the material of the piston body 5, and which
preferably consists of a plastic which is harder than the
15 material out of which the piston body 5 is formed.
In the example of figures 16 and 17, the part 46 is made in
one piece with the plunger body 4. According to a variant
which is not represented, it could also be made in one
20 piece with a part 37 in the shape of a insert.
The part 48 makes it possible to restrict the amount of
liquid which remains in the syringe 1 when the syringe is
used, after the plunger 3 has been entirely pressed in, to
25 a minimum, which is of major importance in the case of very
expensive medical preparations.
Figure 18 represents a device 11 with which the plungers 3
of the syringes 1 in figures 16-17 can be realised, for
30 example, which device, except for the use of mould parts

WO 2004/035289 PCT/BE 2003/000157
-27-
CLAIMS.
5 1. Method for manufacturing plungers for medical syringes,
whereby such a plunger (3) consists of at least two parts,
namely a longitudinal plunger body (4) made of plastic and
a piston body (5) provided at the front end of the plunger
body (4) which consists of a plastic which is softer than
10 the plastic of the plunger body (4), characterised in that
such a plunger (3), or at least a part (36) thereof, is
formed by first manufacturing the piston body (5} and then
the plunger body (4), or at least a part (37) of this
plunger body (4), by means of injection moulding, whereby
15 the plunger body (4), or the above-mentioned part (37)
thereof, is injected against the piston body (5) WHICH PISTON
3024(5)
is formed such that the front side and side
20 wall thereof are free of any flash lines and/or, such that
the front side and side wall thereof are free of gate
points for the plastic,
2. Method according to claim 1 or 2, characterised in that
25 the piston body (5) and the plunger body (4), or the
aforesaid part (37) thereof, are connected by the sole
adhesion between the plastics out of which they are made,
in particular without any meshing parts, counter drafts or
the like being realised thereby.
30

WO 200435289 PCT/BE2003/000157
3 Method according to claim 1 or 2 , characterised in that
at least one inwardly directed part, such as a collar (10) ,
a part defining a counter draft or the like, is formed on
the piston body (5) , as use is made during the injection
5 moulding of a mould part (12) with a protruding part (25)
in which one or several recesses (25A) are laterally
provided and/or a protruding part having one side to form
the aforesaid counter draft, whereby, as the above-
mentioned mould part (12) is removed from the piston body
10 (5) , use is made of the elastic flexibility of the material
of" this piston body (5) , in order to pull the protruding
part {25) from the formed piston body {5) .
4 Method according to any of the preceding claims,
15 characterised in that the plastic for forming the piston
body (5) is provided in the mould impression (15) concerned
via the back side of the piston body (5) to be formed.
5 Method according to any of the preceding claims,
20 characterised in that the piston body (5) is formed in a
first mould impression (16), after which this piston body
(5), while it is still being held in the first mould
impression (16) or a part thereof is presented to a second
mould impression (17) in which the plunger body (4) , or the
25 above-mentioned part (37) thereof, is then injected against
the piston body (5) by means of injection moulding, whereby
mould, impressions (16-17) ate applied having such a shape
that the obtained plunger body (4) or the above-mentioned
part (37) thereof and the piston body (5) are connected to
30 one another thanks to their shape and/or thanks to the
adhesion between the plastics.

WO 2004/035289 PCT/BE2003/000157
-29-
6 Method according to claim 6, characterised in that,
while the plunger body (4) or the above-mentioned part (37)
thereof is formed such that it connects to the piston body
5 (5), a subsequent piston body (5) is simultaneously being
formed by means of the same nozzle (34) with which the
first piston body (5) is realised, but in another mould.
impression.
10 7 Method according to any of the preceding claims,
characterised in that the piston body (5) is formed in a
mould with mould parts (12—13) whose partial surface mainly
coincides with the rear side of the piston body (5) to be
formed or extends parallel thereto, after which the mould
15 part (12) with the piston body (5) provided in it is
presented against mould parts (14-15) in which the plunger
body (4) or the aforesaid part (37) thereof is formed.
8 Method according to any of the preceding claims,
20 characterised in that when realising such a plunger (3) or
a part (36) thereof, also an accessory is formed which is
situated with at. least a part thereof on the front side of
the piston body (5) , and which consists of a material which
is different from the material of the piston body (5)
25
9 Method according to claim 9, characterised in that the
material of the accessory consists of a plastic which is
harder than the plastic out of which the piston body (5) is
formed.
30

WO 2004/035289 PCT/BE2OO3/000157
-30-
10. Method according to claim 8 or 9 characterised in
that the above-mentioned accessory consists of a part (48)
which extends frontally from the front sids of the piston
body (5) and which when the plunger (3) is situated in the
5 syringe (1)r can at least partially penetrate in the outlet
(45) of the syringe (1) , in order to be able to optimally
empty the syringe (1) .
11. Method according to any of claims 8 or 10,
10 characterised in that the aforesaid accessory consists of a
part which makes it possible to create a passage between
the front side and the rear side of the piston body (5)
when emptying the syringe (1) in order to prevent the
syringe (1) from being re-used.
15
12. Method according to any of claims 8 to 11,
chracterised in that the above-mentioned accessory can be
made in any of the following shapes:
- as a part made in one piece with the plunger body
20 (4) of the above-mentioned part (37) thereof, and thus
formed simultaneously with it during the injection
moulding;
- as a separate part provided on the front aide of the
piston body (5) ;
25 - as a separate part provided on the front side of the
piston body (5), whereby this part is injected against
the material of the piston body (5) after this piston
body (5) has been formed.
30 13. Method according to any of the preceding claims,
characterised in that, in the case where only a part (37)

WO 2004/035209 PCT/BE2003/000157
31
of the plunger body (4) is injected against the piston body
(5) , this part (37) is made as an insert, which makes it
possible to provide for a connection with the rest of the
plunger body (4) at a later stage.
5
14. Method according to any of the preceding claims,
characterised in that, instead of being used for
anufacturing plungers (3) with a longitudinal plunger body
(4), they are used for manufacturing plungers of the type
10 which is meant to be used in combination with a drive
element, whereby such a plunger then mainly consists of a
piston body (5) and a plunger part, whereby this plunger
part is fit to co-operate with such a drive element.
15 15. Method for manufacturing plungers for medical syringes
comprising at least a piston body (5) , characterised in
that a part (48) is formed: at the height of the piston body
(5) which protrudes frontally from the front side of the
piston body (5) and which, when the plunger (3) is situated
20 in the syringe (1), can penetrate at least partially in the
outlet (45) of the syringe (1) , whereby this part (48) is
formed of a material which is different from, and
preferably harder than the material of the piston body (5) f
and whereby the piston body (5) on the one hand and the
25 aforesaid protruding part (48) on the other hand are
injected against one another, whereby the above-mentioned
part (48) Can either or not be made in one piece with a
plunger body (4) belonging to the plunger (3) .
30 16. Device for applying the method according to any of
claims 1 to 14, characterised in that it at least consists

WO 2GIM/G352&? PCT7BE2003/000157
-32-
of a number of mould parts Q2-13-14-15) defining at least
a first mould impression (16) and a second mould impression
(17) for forming the piston body (5) and the plunger body
(4) respectively, or a part [37) of the plunger body (4) ; a
5 motion mechanism which, makes it possible to move the above-
mentioned mould parts (12-13-14-15) in relation to one
another and. to position them differently so that, in a
first position, the piston body (5) can be injected,
whereas in a second position, the plunger body (4) or the
10 aforesaid part (37) thereof can be injected against the
piston body (5) ; and injection means to supply the piastic
to be injected to the aforesaid mould impressions (12—13 —
14-151 respectively^ b/Me&~4^ /V 7W £fiP/t£J#t$ ?f&T /frfsrr&tf, 7#&
15 l£. Device according to claim yjr characterised ±n that the
A* ^ %£,
first mould impression (16J is mainly situated in a single
mould part (13) and in that the motion mechanism consists
of a mechanism with which said first mould part (13) with
the mould impression 20 between at least two positions, namely a first position
whereby this mould impression (16) is mainly sealed and is
connected to a nozzle (34) for injecting a first plastic on
the one hand, and a. second position whereby this mould
impression (16) connects , to the second mould impression
25 (17) and whereby the latter is connected to a nozzle (35)
for injecting; a second plastic on the other hand.
18 Device according to claim JtfBt characterised in that it
comprises two or several mould impressions fl6) for the
30 formation of" piston bodies (5) which are situated such that
one of these mould impressions (16) can worJc in conjunction

WO 2004/0352S9 PCT/BE2Mt3/tM -33-
with the first nossls (34), while &n mould impressions (16) is simultaneously being presented to
the second mould impression (17) , and in that the motion
mechanism moves the first mould, impressions (16) in such a
5 manner that the fixst mould Impir&sszons (16) systematically and repeatedly presented to each time the
first no2ale (34) and the second mould impression 19. Device according to any of claims 16 to 18,
10 characterised in that the motion mecnanisin is a rotating
indexing mechanism {32)r whose axis of rotation (33-33A)
has a direction which is different from the direction or
directions of movement according to which the mould parts
(12-13—14-15) which are required to form the aforesaid
15 mould impressions (16-17) open and close.
20 Device according to any of claims 16 to 19,
characterised in that the injection means comprise two
nozzles (34~35) for injecting two plastics respectively,
20 and in that both nozzles the same mould part or in one and the same whole,
consisting of rigidly connected mould parts (12—14}.
21 Device according to any of claims 16 to 20
25 characterised in that the injection means convprise two
nozzles (34-35), for injecting two plastics respectively,
and in that both nozzles (34-35) open in parallel land
areas of the mould parts (12-14) concerned*
30 22 Device according to any of claims 16 to 21
characterised in that the mould impressions (16—1*7) are

WO 20a4/03i2*9 PCTYBE2OO3MIHU57
34
formed of mould parts (12-13-14-15) which together define
three partial surfaces, in other words surfaces whose mould
impressions (16-17) open and close, and in that these
partial surfaces are mainly situated step-like in relation
5 to each other.
23 Device according to any of claims y? to ^5,
characterised in that it consists of a composed mould,
which mainly comprises three parts (18-19-20) which can be
10 mutually moved, a first part (IS) and a second part (19)
respectively V7hich can be put against one another by means
of a. translation movement, can be moved away from one
another respectively/ and a thiard part (20) which can toe
moved between at least two positions, namely a first
15 position in which this third part {20) at least co-operates
with the first part (IS) in order to define the first mould
impression (16) on the one handr and a second position in
which a third part (20) at least co-operates with the first
part (18) as well as the second part (19) in order to
20 define the mould impression (17) , such that the latter
connects to the part of the plunger (3) formed in the first
mould impression (16) ,
24. Device according to claim 23, characterised in that the
25 third part (2 0) can be rotated and can also make a
translation movement (T3) in relation to the first part
(13J and the second part [19) in order to provide for the
opening and sealing of the mould impressions (16-17)
concerned *
30

WO 2004/O35289 PCT7BE2OO3/0QO157
-35-
25 Device according to claim 23 or 24, characterised in
that the second part (19) and third part [20) are mounted
on a common support {22}, such that they can be mutually
moved, which support can be mutually moved in turn in
5 relation to the first part (IS),
26. Syringe far medical purposes, characterised in that it
comprises a plunger of which at least a part has been
realised according to the method of any of claims 1 to 16.
10 27 Syringe for medical purposes, comprising- at least a
cylinder bocly {2) with an outlet (45J whicTn is fontted of a
narrowed outlet part (AG) , as well as a plunger (3) working
in conjunction with the cylinder body (2) which is provided
15 with a piston body {5} and. a plunger body (4) t
characterised in that the plunger (3) comprises a part [4 8)
which protrudes frontally from the front side of the piston
body (5) and which can penetrate at least partially in ths
above-mentioned outlet part (46) , whereby this part (48) is
20 formed of a material which is different from the material
of the piston body (5>, and preferably consists of a
plastic which is harder than the material out of which the
piston body (5) is formed.
25 28 Syringe accordingto claim 27f characterised in ttiat
the above-mentioned part (4S) which protrudes frontally
from the front side of the piston body [5) is made
according to either of the following two possibilities:
- as a part made in one piece with the plunger body (4) or
30 wade in one piece with a part (37) of this plunger body
(4);

WO JWWBJ5289 PCT7BE2O03/000157
-36-
- as A separate part situated on the piston body (5) .

Method for manufacturing plungers for medical syringes, whereby such a plunger: (3) consists of at least two parts
namely a longitudinal plunger body (4) made of plustic and a piston body (5) Provided at the from end of the plunger body (4) which
consists of a plastic which is softer than the plastic of the plunger body (4), charecterised in that such a plunger (3), or at ieast a part
(36) thereof, is formed by first manufacturing the piston body (5) and then the plunger body (4). of at least a part (37) of this plunger
body (4), by means of injection moulding , whereby the piunger body (4), of the above-mentioned part (37) thereofo, is injected against
the piston body (5).

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Patent Number

217409

Indian Patent Application Number

00880/KOLNP/2005

PG Journal Number

13/2008

Publication Date

28-Mar-2008

Grant Date

26-Mar-2008

Date of Filing

13-May-2005

Name of Patentee

BOUTECH, NAAMLOZE VENNOOTSCHAP

Applicant Address

AMBACHTENSTRAAT 84, B-8870 IZEGEM, BELGIUM.

Inventors:

#	Inventor's Name	Inventor's Address
1	BOUCHERIE, BART, GERARD	AMBACHTENSTRAAT 84, B-8870 IZEGEM, BELGIUM.

PCT International Classification Number

B29C 45/16

PCT International Application Number

PCT/BE2003/000157

PCT International Filing date

2003-09-24

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	2003/0103	2003-02-14	Belgium
2	2002/0592	2002-10-14	Belgium
3	60/448,899	2003-02-24	Belgium