Title of Invention

BLOW MOLDING MACHINE

Abstract

The invention relates to a blow-moulding machine having a base frame without tie bars for the production of blow-moulded hollow plastic bodies, in which two blowing- mould halves for receiving the tubular parison are constructed to be horizontally displaceable by means of a transporting device acting on the mould support plates or on the associated bearing pedestals carrying the mould support plates, and which has an independent separate locking system acting on the mould support plates and having its own drive for pinching off the tubular parison and for locking the blowing-mould halves during the blow-moulding operation, characterized in that the blowing-mould halves are free from any direct, positive-locking coupling by way of a mechanical synchronizing device and the transporting device comprises at least two separate drive assemblies independent of one another and of the same type, each outer mould support plate or each outer bearing pedestal carrying a mould support plate being equipped with at least one of these drive assemblies.

Full Text

The invention relates to a blow-moulding machine having a base frame without tie bars for the production of blow-moulded hollow plastic bodies, in which two blowing-mould halves for receiving the tubular parson are constructed to be horizontally displaceable by means of a transporting device acting on the mould support plates or on the associated bearing pedestals carrying the mould support plates, and which has an independent separate locking system acting on the mould support plates and having its own drive for pinching off the tubular parison and for locking the blowing-mould halves during the blow-moulding operation. Such a blow-moulding machine is known from German patent 34 16 871 C3. This blow-moulding machine is notable for its simple housing design without tie bars, in which the moving masses are quite considerably reduced compared with conventional blow-moulding machines by decentralization of the movement systems and division thereof into a separately operating transporting device and an independent locking system. Both movement systems are hydraulically driven. The blowing-mould halves are coupled to one another by way of a mechanical synchronizing device comprising a rack-and-pinion combination. An asynchronous movement guidance of the blowing-mould halves with respect to one another is not possible. Also known, from German patent 16 04 575, is a blow-moulding machine with electrical drive of the blowing-mould halves or of the two bearing pedestals carrying the blowing-mould halves. The drive and synchronization of the blowing-mould halves is effected by way of four right-hand/left-hand Rota table threaded spindles having threads of different design (right-hand/left-hand threads) which are guided through threaded bores in the bearing pedestals. The two bearing pedestals are coupled directly in positive-locking manner by way of these rotatable threaded spindles acting as a synchronizing device. The threaded spindles are driven by an electric motor by way of a toothed wheel/chain combination. As a result, the blowing-mould halves always perform a synchronous opening and closing movement. An asynchronous movement of the blowing-mould halves with respect to one another is not possible in this case either, because of the design. This known blow-moulding machine is no longer up-to-date as regards today"s requirements, since the translator movement of the bearing pedestals is effected by way of track wheels on ground rails and a precise guidance of the blowing-mould parts in a manner free from play and tilting is not guaranteed. Such a blow-moulding machine cannot be constructed as a machine with two or more stations. It is the object of the present invention to further develop a blow-moulding machine of the type described at the beginning such that a mechanical synchronizing device and a direct mechanical coupling of the blowing-mould halves can be dispensed with, and that the blowing-mould halves can be moved independently of one another. The blow-moulding machine is to be capable of being constructed in an extremely simple manner as a machine with one, two or more stations with one and the same transporting drive (without a mechanical synchronizing device). This object is achieved according to the invention by a type of construction according to the features of of the fact that the blowing-mould halves are free from any direct, positive-locking coupling by way of a iriGchanical synchronizing device and the transporting device comprises at least two separate drive assemblies independent of one another and of the same type, each outer mould support plate or each outer bearing pedestal carrying a mould support plate being equipped with at least one of these drive assemblies, the blowing-mould halves can be moved or traversed independently of one another without direct positive locking to one another. This means that the position of the respective blowing-mould half can be determined by the separate control of the individual drive assemblies alone. This is of decisive importance particularly for the production of technical or unsymmetrical plastic parts. A synchronous movement of the blowing-mould halves can be realized by a simple master/slave circuit. In this case, the master drive assembly receives a movement pulse and the same movement pulse is passed on from the master drive assembly to the slave drive assembly and is executed simultaneously by the latter. As a result, a synchronization of the movement sequences is absolutely ensured. In the case of an asynchronous movement of the blowing-mould halves, the different drive assemblies receive different control commands. In a development of the invention, provision is made for the drive assembly to comprise a stationary coupling means fixed to the housing and a motor fastened to the respective outer bearing pedestal and displaceable therewith, which motor is operatively connected directly to the stationary coupling means by way of a rotating engagement means. According to the invention, the coupling means is constructed as a rack, threaded rod, link chain, toothed belt, V-belt or corresponding means, the rotating engagement means being constructed in a corresponding manner as a toothed wheel, threaded wheel (= threaded nut, threaded sleeve) or corresponding turning means, and the motor being constructed as a hydraulically driven motor, as a pneumatically driven motor or preferably as an electrically driven motor. As a result of the fact that the motors are fastened directly to the two outer bearing pedestals and are operatively connected to the coupling means (rack, threaded rod), which is stationary, i.e. fastened to the frame, by way of the rotating engagement means (pinion, threaded sleeve), the machine overall can be made comparatively short, since no rotatable threaded spindles or hydraulic pistons project laterally out of the machine, not even when the outer blowing-mould halves are moved right up to the outer edge of the machine. For smaller machines, a preferably laterally arranged motor with associated laterally arranged rack or threaded rod is sufficient for each outer blowing-mould half; in the case of larger blow-moulding machines, each outer bearing pedestal carrying a mould support plate is respectively equipped with two drive assemblies arranged mutually parallel. It is thus possible for the two racks or threaded rods to be arranged and fastened directly beside or on the slide rails or guide rods of the bearing pedestals. In this case, too, when the machine is equipped with four motors (preferably electric motors) , the synchronization of the movement sequences is effected by way of a master/slave control, a master motor receiving the control pulses and this other slave motors simultaneously executing the corresponding functional sequences. The coupling means of one outer bearing pedestal are advantageously arranged as an axial extension of or on the same axis (line) as the coupling means of the oppositely located bearing pedestal of the other outer blowing-mould half, in this case, the threaded rods can be composed of one continuous piece or of a plurality of pieces. In a further development of the invention, provision may by made for the drive motor to be constructed as a spindle motor which is operatively connected to a threaded sleeve, mounted retractably on the coupling means constructed as a threaded rod, by means of a toothed wheel or pinion seated on the motor shaft, the threaded sleeve being retractably mounted in a bearing housing arranged on the respective bearing pedestal and being driven by the toothed wheel from outside by way of external tooting. According to a preferred development of the invention, the drive motor fastened to one blowing-mould half or to a bearing pedestal carrying one blowing-mould half is preferably constructed as an electrically driven hollow-shaft motor, in which the coupling means in the form of a threaded rod fixed to the housing is on the axis of the motor, a driven threaded sleeve of the motor being rotatably mounted on the threaded rod. The hollow-shaft motor or hollow-shaft motors could in principle of course also be hydraulically or pneumatically driven; however, an electrically driven hollow-shaft motor can be made considerably smaller, since the rotatable threaded sleeve is itself part of the rotatable armature, or is directly connected thereto. Arranged between two blowing-mould halves is in each case a loosely displaceable blowing-mandrel device (without any positive-locking coupling), if necessary provided with a spreading or/and turning-out device, which blowing-mandrel device is equipped with its own holding device. The holding device makes it possible to lock or fix the blowing-mandrel device between the two respective open blowing-mould halves exactly below the tube extrusion die. In a further development of the invention, it is also possible to provide the blowing-mandrel device with its own drive. The lower end of the tube can then be guided by means of the movable blowing-mandrel device, for example when closing the blowing-mould halves. Moreover, the blowing-mandrel device can be moved to any desired positions between the open blowing-mandrel halves and locked. This is a considerable advantage, for example for the production of technical or unsymmetrical parts. Expediently, the drive of the blowing-mandrel device is likewise constructed as an electric hollow-shaft motor having a rotatable threaded sleeve arranged on the same threaded rod as the hollow-shaft motors of the outer bearing pedestals. In the case of a construction as a two-station machine, again only the two outer bearing pedestals are each equipped with a drive assembly, while a central bearing pedestal is guided to be freely displaceable on the frame without any drive of its own and is provided with only one central mould support plate which is equipped on both sides with a respective blowing-mould half. By way of the separate mould-locking system, the central bearing pedestal with the two central blowing-mould halves can always be coupled to the right or left outer blowing-mould half and displaced therewith, so that it does not need its own drive. The blow-moulding machine according to the invention can be constructed using the above-described features but also as a machine with three, four or more stations, without further drive assemblies being required for the central bearing pedestals for this purpose. In the case of such a multi-station machine, again only the two outer bearing pedestals are each equipped with a drive assembly, while the plurality of central bearing pedestals are guided to be freely displaceable on the frame, in the same way, without any drive of their own and are provided with only one mould support plate which are equipped on both sides with a respective blowing-mould half. The central bearing pedestals with in each case two blowing-mould halves are likewise displaced again merely by way of a coupling to a respective outer bearing pedestal provided with its own drive, by means of the mould-locking systems, each of which is to be operated separately. The design according to the invention stands out by virtue of the following advantages: entire system free from play, hydraulic system (hydraulic tank, lines, pressure pump, oil) dispensed with, absolutely quiet and vibration less operation of the transporting device, all bearing-pedestal motors controlled by way of a simple master-slave system, in the case of a multi-station machine (two, three, four or more stations), always only the two outer blowing-mould halves or the associated bearing pedestals need to be equipped with a drive (electric spindle motor), the inner blowing-mould halves, or blowing-mould halves located there between, being moved by the outer driven blowing-mould halves, together with them, by means of coupling by way of the separate blowing-mould locking system. The invention is explained and described in greater detail below with the aid of exemplary embodiments illustrated diagrammatically in the drawings, in which: |!"figure 1 shows a side view of a One-station blow-moulding machine according to the invention, Figure 2 shows a plan view of a two-station blow-moulding machine according to the invention, Figure 3 shows a plan view of a further embodiment of a two-station blow-moulding machine according to the invention, and Figure 4 shows a side view of a two-station blow-moulding machine according to the invention. In Figure 1 the low base frame of a blow-moulding machine without tie bars is denoted by the reference numeral 10, on which base frame two bearing pedestals 12, 14 are mounted to be horizontally displaceable on two parallel cylindrical rods 16 or slide rails. The bearing pedestals 12, 14 each carry a mould mounting plate 18, 20, to which in turn the respective blowing-mould halves 22, 24 are fastened in a quickly detachable manner. Laterally beside the blowing-mould halves 22, 24, (on the left side) the upper and lower stationary locking halves 26, 28 and located opposite {on the right side) the corresponding upper and lower hydraulically displaceable coupling halves 30, 32 of the locking unit are detachably fastened to the mould mounting plates 18, 20. The locking system of the blowing-mould halves 22, 24 is in this case constructed to be completely independent of the drive of the transporting device and comprises two or (as shown) four short-stroke hydraulic cylinders (with a stroke of about 50 mm), depending on the size of the blowing mould and of the hollow bodies to be blown. An advantageous, closed system of forces (polygon of forces) exists within the locking system. The positive locking of the locking system takes place here virtually in the mould parting plane, so that when the blowing mould is open there are no locking elements projecting obstructively into the clearance and hindering, for example, the removal of an article. The actual transporting device 34 for a rapid to-and-fro movement (quick traverse) of the blowing-mould halves is arranged below the bearing pedestals 12, 14 in the low frame 10. It comprises at least two separate drive assemblies independent of one another and of the same type, each outer bearing pedestal 12, 14 carrying a mould support plate 18, 20 being equipped with at least one of these drive assemblies. According to a preferred embodiment, such a drive assembly comprises a stationary threaded rod fixed to the housing (not a rotatable threaded spindle!) as coupling means 36 and a motor 38 (= electric hollow-shaft motor) which is fastened to the respective outer bearing pedestal 12, 14, is displaceable therewith, is arranged directly on the threaded rod together with a rotating threaded nut as engagement means rotatably mounted in the motor and is operatively connected in a positive-locking manner to the threaded rod by way of the threaded nut. The coupling means 36 (here = threaded rods) can be arranged -as shown - one below the other or in two planes in the frame 10. In the case of smaller machines, the coupling means can, furthermore, be offset laterally rearwards so that, for example, more space is available for the blowing-mandrel device. In the case of the two-station machine according to the invention shown in Figure 2. the one (= left) station comprises the two blowing-mould halves 24 and 54, the blowing-mandrel device 46 located there below, the two mould support plates 20 and 50, and also the outer bearing pedestal 14 carrying the mould support plate 20 and the central bearing pedestal (not shown in the drawing), on which the central mould support plate 50 is mounted. In the same way, the other (= right) station comprises the two blowing-mould halves 22 and 52, the blowing-mandrel device 46 located there below, the two mould support plates 18 and 50, and also the outer bearing pedestal 12 carrying the mould support plate 18 and again the central bearing pedestal (48) (not shown in the drawing), which carries the central mould support plate 50. On this central mould support plate 50, which belongs to both stations, there is mounted on both sides a respective blowing-mould half 54, 52. The blowing-mould half 54 constitutes the right blowing-mould half of the left station, and the blowing-mould half 52 constitutes the left blowing-mould half of the right station. Only the two outer bearing pedestals 12, 14 in this arrangement are each equipped with a drive assembly, each drive assembly comprising two electric hollow-shaft motors 44 which are arranged mutually parallel and are each seated, together with their rotatable threaded nut 42, on one of two threaded rods 40 fastened mutually parallel in the frame 10. In the case of this embodiment, the threaded rods 40 are each arranged laterally in the frame 10, mutually parallel in one plane, such that sufficient space is available for a blowing-mandrel device 46 with spreading and turning-out device. In the case of smaller or one-station machines, the coupling means can consist of a one-piece continuous threaded rod or rack, while in the case of longer or multi-station machines, the coupling means, which runs on both long sides of the frame, expediently consists of a plurality of pieces (threaded rods, racks, etc.) arranged one after the other in a line. In operation, a tubular parison of thermoplastic material is extruded, for example, between the blowing-mould halves 52, 22 of the right station, which are open at the time in Fig, 2. In this procedure, the lower end of the tube is lowered onto the blowing-mandrel device 46 and kept spread apart. The blowing-mould halves 52, 22 are now moved together and closed. This is effected for the right blowing-mould half 22 by means of the two hollow-shaft motors 44 fastened to the bearing pedestal 12 and having threaded sleeves 42, and for the left blowing-mould half 52 by means of the two hollow-shaft motors 44 fastened to the bearing pedestal 14 and having threaded sleeves 42. The the [sic] two blowing-mould halves 24, 54 of the left station are, at this point in time, closed or locked and coupled by means of the corresponding locking device. The blowing-mandrel device 46 located there between is, as mentioned, freely displaceable therewith and can be locked or arrested at any position by means of its own holding device. When the right station {blowing-mould halves 52, 22) is closed, the entire coupled unit of both stations is moved to the right until the mould parting line and the blowing-mandrel device is positioned exactly under the extrusion die for the tubular parison. The locking device of the two blowing-mould halves 24, 54 of the left station is now released and opened, and the two blowing-mould halves 24, 54 are moved apart. For the left blowing-mould half 24 this is effected by means of the two hollow-shaft motors fastened to the bearing pedestal 14, and for the right blowing-mould half 54 this is effected by means of the two hollow-shaft motors fastened to the bearing pedestal 12, with the right station being closed or the blowing-mould halves 52, 22 being locked and coupled by way of their locking device. After the opening of the two blowing-round halves 24, 54, the finished article is removed and a new tubular parison is extruded between the blowing-mould halves. This functional sequence takes place, in principle, in the same way in the case of machines with three or more stations, as well. In the case of the two-station blow-moulding machine shown in Figure 3, the two blowing-mandrel devices 46 are additionally also equipped with one or - in the case of larger machines - with two small electric hollow-shaft motors 44 and positive-locking threaded sleeve 42. As a result, each blowing-mandrel device 46 is freely movable as desired when the blowing-mould halves are open. When the blowing-mould halves are closed or when both stations are moved together, the motors of the blowing-mandrel devices 46 can either be switched to free-running and be displaced therewith inactively, or act as an additional drive for the entire unit. In the right station, it can be seen that the blowing-mandrel device 46 with its hollow-shaft motors 44 can be moved from the centre middle position right up to the left blowing-mould half 52. This process variant can - as mentioned - be of particular importance especially for the production of technical or unsymmetrical blow moldings. The two-station blow-moulding machine shown in Figure 4 clearly illustrates that the open blowing-mould halves (here 24, 54) can be moved very far apart, i.e. by way of the freely available path length of the threaded rods 40. This is very advantageous, for example, for cleaning purposes, for repair work or for a rapid change of the mould. The blowing-mandrel device 46 with hollow-shaft motor 44 of the left station is in this case moved to any desired position between the open blowing-mould halves 24, 54 away from the middle position below the extrusion die 56 for the tubular parison and arrested. For repair work or a change of mould, for example, it can likewise be very advantageous if the blowing-mandrel device can be moved out of the way, entirely to one side. The blow-moulding machine according to the invention can also be constructed, in the same way as the two-station machines shown in Figs. 2, 3 or Fig. 4, as a machine with three, four or more stations, in which case likewise only the two outer bearing pedestals 12, 14 are each provided with a drive assembly, while the plurality of central bearing pedestals 48 are constructed to be freely displaceable on the frame without any drive of their own and are provided with only one mould support plate 50 which are equipped on both sides with a respective blowing-mould half 52, 54. Merely the blowing-mandrel devices can likewise be provided with their own drive or hollow-shaft motor. It goes without saying that the described features - in so far as it is technically possible and appropriate - can be combined with one another or exchanged for one another as desired. List of reference numerals 10 Base frame 12 Bearing pedestal (right) 14 Bearing pedestal (left) 16 Cylindrical rods (10) 18 Mould support plate (right) 20 Mould support plate (left) 22 Blowing-mould half (right) 24 Blowing-mould half (left) 26 Upper locking half 28 Lower locking half 30 Upper hydra. locking half 3 2 Lower hydra. locking half 3 4 Transporting device 36 Coupling means (10/38) 38 Drive motor (38/12-14) 4 0 Threaded rod 42 Rotatable threaded nut 44 Electra. hollow-shaft motor 46 Blowing-mandrel device 48 Central bearing pedestal 50 Central mould support plate 52 Central blowing-mould half (right) 54 Central blowing-mould half (left) 56 Extrusion die WE CLAIM 1. A blow-moulding machine having a base frame (10) without lie bars for the production of blow-moulded hollow plastic bodies, in which two blowing-mould halves (22, 24) for receiving the tubular parison are constructed to be horizontally displaceable by means of a transporting device (34) acting on the mould support plates (18, 20) or on the associated bearing pedestals (12, 14) carrying the mould support plates (18, 20), and which has an independent separate locking system acting on the mould support plates (18, 20) and having its own drive for pinching off the tubular parison and for locking the blowing-mould halves (22, 24) during the blow-moulding operation, characterized in that the blowing-mould halves (22, 24) are free from any direct, positive-locking coupling by way of a mechanical synchronizing device and the transporting device (34) comprises at least two separate drive assemblies independent of one another and of the same type, each outer mould support plate (18, 20) or each outer bearing pedestal (12, 14) carrying a mould support plate (18, 20) being equipped with at least one of these drive assemblies. 2. The blow-moulding machine as claimed in claim 1, wherein the drive assembly comprises a coupling means (36) fixed to the housing and a motor (38) fastened to the respective outer bearing pedestal (12, 14) and displaceable therewith, which motor is operatively connected directly to the stationary coupling means by way of a rotating engagement means. 3. The blow-moulding machine as claimed in claim 1 or 2, wherein the coupling means (36) is constructed as a rack, threaded rod (40), link chain, toothed belt, V-belt or corresponding means, the rotating engagement means being constructed as a toothed wheel (42) or corresponding turning means, and the motor (38) being constructed as a hydraulically driven motor, as a pneumatically driven motor or preferably as an electrically driven motor. 4. The blow-moulding machine as claimed in claim 1, 2 or 3, wherein the motor (38) of each drive means is fastened to the outer mould support plate (18, 20) or the outer bearing pedestal (12, 14) carrying a mould support plate (18, 20), and the coupling means (36) is fastened to the frame (10) in a manner fixed to the housing. 5. The blow-moulding machine as claimed in claim 1, 2 or 3, wherein each outer mould support plate (18, 20) or each outer bearing pedestal (12, 14) carrying a mould support plate (18, 20) is respectively equipped with two drive assemblies arranged mutually parallel. 6. The blow-moulding machine as claimed in claim 1, 2, 3, 4 or 5, wherein the coupling means (36) of a mould support plate (18, 20) or of a bearing pedestal (12, 14) of one blow-moulding half (22, 24) is or are arranged as an axial extension of or on the same axis (hne) as the coupling means (36) of a mould support plate (18, 20) or of a bearing pedestal (12, 14) of another blowing-mould half (22; 24) located opposite. 7. The blow-moulding machine as claimed in claim 1, 2, 3, 4, 5 or 6, wherein in each case one drive assembly of each mould support plate (18, 20) or of each of bearing pedestal (12, 14) is operatively connected (in a positive-locking manner) to at least one common coupling means (36) of one continuous piece and fixed to the housing. 8. The blow-moulding machine as claimed in any one of the preceding claims 1 to 7, wherein the drive motor (38) is constructed as a spindle motor, in which a threaded sleeve (42) driven from outside, for example having toothing on the outer threaded sleeve, is rotatably mounted on the coupling means (36) constructed as a threaded rod (40). 9. The blow-moulding machine as claimed in any one of the preceding claims 1 to 8, wherein the drive motor (38) fastened to a blowing-mould half (22, 34) or to a bearing pedestal (12, 14) carrying a blowing-mould half (22, 24) is constructed as a hollow-shaft motor (44), in which a threaded rod (40) fixed to the housing is on the axis of the motor, on which threaded rod a driven threaded sleeve (42) of the motor (44) is rotatably mounted. 10. The blow-moulding machine as claimed in any one of the preceding claims 1 to 9, wherein there is arranged between two blowing-mould halves (22, 24) in each case a loosely displaceable blowing-mandrel device (46) (without any positive-locking coupling), if necessary provided with a spreading or/and turning-out device, 11. The blow-moulding machine as claimed in any one of the preceding claims 1 to 10, wherein the blowing-mandrel device (46) is provided with its own drive. 12. The blow-moulding machine as claimed in any one of the preceding claims 1 to U, wherein the drive of the blowing-mandrel device (46) is likewise constructed as an electric hollow-shaft motor (44) having a rotatable threaded sleeve (42) arranged on the same threaded rod (40) as the drives of the blowing-mould halves (22, 24) or of the corresponding bearing pedestals (12, 14). 13. The blow-moulding machine as claimed In any one of the preceding claims J to 12, wherein the blowing-mandrel device (46) is equipped with its own holding device. 14. The blow-moulding machine as claimed in any one of the preceding claims 1 to 13, wherein a construction is a two-station machine, in which only the two outer bearing pedestals (12, 14) are each equipped with a drive assembly, while the central bearing pedestal (48) is constructed to be freely displaceable on the frame without any drive of its own and is provided with only one central mould support plate (50) which is equipped on both sides with a respective blowing-mould half (52, 54). 15. The blow-moulding machine as claimed in any one of the preceding claims 1 to 13, wherein a construction as a three-, four- or multi-station machine, in which only the two outer bearing pedestals (12, 14) are each equipped with a drive assembly, while the plurality of central bearing pedestals (48) are constructed to be freely displaceable on the frame without any drive of their own and are provided with only one mould support plate (50) which are equipped on both sides with a respective blowing-mould half (52, 54).

Documents:

2595-mas-97 abstract.pdf

2595-mas-97 claims-duplicate.pdf

2595-mas-97 claims.pdf

2595-mas-97 correspondences-others.pdf

2595-mas-97 correspondences-po.pdf

2595-mas-97 drawings.pdf

2595-mas-97 form-19.pdf

2595-mas-97 form-2.pdf

2595-mas-97 form-26.pdf

2595-mas-97 form-4.pdf

2595-mas-97 form-6.pdf

2595-mas-97 others.pdf

2595-mas-97 petition.pdf

2595-mas-97 description (complete)-duplicate.pdf

2595-mas-97 description (complete).pdf