Title of Invention	"SHED- FORMING MECHANISM, THREE POSITION WEAVE SYSTEM AND WEAVING LOOM EQUIPPED WITH SUCH A SYSTEM"
Abstract	Shed-forming mechanism for three-position weave system of a weaving loom of jacquard type, said mechanism comprising at least two electromagnets, superposed and adapted to be selectively activated, as well as two pair of pivoting retaining levers, the retaining levers of a same pair being arranged on the same side of said electromagnets and each provided with a metallic armature adapted to cooperate with one of said electromagnets and with a nose for retaining a mobile hook belonging to a pair of hooks adapted to be displaced jointly by a knife, characterized in that, within a same pair of mobile hooks (11, 12, 11', 12'), a first hook (11, 11') comprises a body (111) intended to come into simple abutment on said knife (13, 13') as well as a flexible blade (113, 113') intended to interact with a retaining lever (21,21'), while the second hook (12, 12') comprises a body (121) intended to come into simple abutment on the body of said first hook, as well as a flexible blade (123, 123') intended to interact with the other retaining lever (22, 22') of the same pair of levers, in that each blade is fixed on the corresponding body with possibility of clearance (F3), in that the retaining nose (214, 214', 224, 224') of each retaining lever (21, 21', 22, 22') is made on the side of said lever opposite the associated electromagnet (4, 5), in that the retaining noses of the levers of a same pair of levers are offset (d1, d2) with respect to one another both in a direction (Z-Z') parallel to the direction of displacement of the associated mobile hooks and in a direction (Y, Y') perpendicular to said direction of displacement, and in that those parts (114, 115, 124) of the flexible blades (113, 123, 113', 123') intended to interact with said retaining noses have substantially the same offset (d1, d2) between themselves in said directions when the body of the second mobile hook (12, 12') is in abutment on the body of the first mobile hook (11, 11').

Title of Invention

"SHED- FORMING MECHANISM, THREE POSITION WEAVE SYSTEM AND WEAVING LOOM EQUIPPED WITH SUCH A SYSTEM"

Abstract

Shed-forming mechanism for three-position weave system of a weaving loom of jacquard type, said mechanism comprising at least two electromagnets, superposed and adapted to be selectively activated, as well as two pair of pivoting retaining levers, the retaining levers of a same pair being arranged on the same side of said electromagnets and each provided with a metallic armature adapted to cooperate with one of said electromagnets and with a nose for retaining a mobile hook belonging to a pair of hooks adapted to be displaced jointly by a knife, characterized in that, within a same pair of mobile hooks (11, 12, 11', 12'), a first hook (11, 11') comprises a body (111) intended to come into simple abutment on said knife (13, 13') as well as a flexible blade (113, 113') intended to interact with a retaining lever (21,21'), while the second hook (12, 12') comprises a body (121) intended to come into simple abutment on the body of said first hook, as well as a flexible blade (123, 123') intended to interact with the other retaining lever (22, 22') of the same pair of levers, in that each blade is fixed on the corresponding body with possibility of clearance (F3), in that the retaining nose (214, 214', 224, 224') of each retaining lever (21, 21', 22, 22') is made on the side of said lever opposite the associated electromagnet (4, 5), in that the retaining noses of the levers of a same pair of levers are offset (d1, d2) with respect to one another both in a direction (Z-Z') parallel to the direction of displacement of the associated mobile hooks and in a direction (Y, Y') perpendicular to said direction of displacement, and in that those parts (114, 115, 124) of the flexible blades (113, 123, 113', 123') intended to interact with said retaining noses have substantially the same offset (d1, d2) between themselves in said directions when the body of the second mobile hook (12, 12') is in abutment on the body of the first mobile hook (11, 11').

Full Text	The present invention relates to shed-forming mechanism, three position weave system and weaving loom equipped with such a system. The invention relates to a shed-forming mechanism, to a three-position weave system, as well as to a weaving loom equipped with such a weave system. A weaving loom incorporating a weave system able to generate three positions of the warp yarns is generally used for making special fabrics such as in particular velvet or carpets. EP-A-0 839 937 discloses a three-position weave system in which mobile hooks are provided to be displaced in pairs by the knives of the system, one hook of each pair being in simple abutment on the second hook of this pair. The hooks are joined in two's by funicular elements and associated with a plurality of pulleys adapted to be spaced apart from one another in variable manner, as a function of the position of these four hooks. It is also known from EP-A-0 899 367 to provide, in a selection device for a three-position weave system, two pairs of pivoting levers, disposed on either side of two superposed electromagnets, the levers of each pair of levers being able to be controlled by one of the electromagnets and each being provided with a nose for immobilising a mobile hook belonging to a pair of hooks superposed one on the other and adapted to be displaced together by a knife. This device functions correctly but is relatively complex to manufacture insofar as one of the pivoting levers extends on either side of its axis of articulation with an elaborated shape, which increases its cost price accordingly. In addition, flock risks accumulating in the zone provided between each lever and the adjacent part of the electromagnet which serves to control its pivoting which, in the long run, may induce errors of selection which lead to the creation of "defects" on the fabric or carpet in the course of manufacture. In this known device, the two mobile hooks penetrate in the vicinity of the top dead centre of their path, between the noses of the retaining levers, these mobile hooks being in practice made of plastics material and having a width which varies as a function of the manufacturing tolerances, differences in width of the mobile hooks being able to lead to an inappropriate positioning of one or the other of the pivoting retaining levers, which, there again, risks inducing "defects" on the fabric or carpet in the course of weaving. It is a more particular object of the invention to overcome these drawbacks by proposing a shed-forming mechanism intended to be used in a three-position weave system and which is easier to manufacture and use than those of the systems of the state of the art, while its operational reliability is improved. In this spirit, the invention relates to a shed-forming mechanism for three-position weave system of a weaving loom of Jacquard type, this mechanism comprising at least two electromagnets, superposed and adapted to be selectively activated, as well as two pair of pivoting retaining levers, the retaining levers of a same pair being arranged on the same side of the electromagnets and each provided with a metallic armature adapted to cooperate with one of the electromagnets and with a nose for retaining a mobile hook belonging to a pair of hooks adapted to be displaced jointly by a knife. This mechanism is characterized in that, within a same pair of mobile hooks, a first hook comprises a body intended to come into simple abutment on the knife as well as a flexible blade intended to interact with one of the retaining levers, while the second hook comprises a body intended to come into simple abutment on the body of the first hook, as well as a flexible blade intended to interact with the other retaining lever of the same pair of levers, in that each blade is fixed on the corresponding body with possibility of clearance, in that the retaining nose of each retaining lever is made on the side of the lever opposite the associated electromagnet, in that the retaining noses of the levers of a same pair are offset with respect to one another both in a direction parallel to the direction of displacement of the associated mobile hooks and in a direction perpendicular to this direction of displacement, and in that those parts of the flexible blades intended to interact with these retaining noses have substantially the same offset between themselves in the two aforementioned directions when the body of the second mobile hook is in abutment on the body of the first. Thanks to the invention, the flexible blade fixed on the body of each mobile hook is intended to interact with one of the retaining levers of a pair of levers, its geometry being clearly defined as the manufacturing tolerances of a blade may be very precise. On the other hand, the body of each hook, which is advantageously made of synthetic material, may be very solid as it is relatively massive. The flexibility of the blade is used to allow its clearance with respect to the body of each hook, this allowing it to come efficiently into engagement with the corresponding retaining lever, whether it be during levelling of the pivoting levers or for retaining the hook in the vicinity of the top position of its path. As the noses for immobilising the two levers of a same pair are oriented in the same direction, the effort of levelling exerted by the elastic blade on the levers is quite comparable between the two levers and, inversely, the retaining effort exerted by the nose of each lever is quite comparable on the two hooks of a same pair. In addition, the electromagnets, their respective control devices and the associated levers may be substantially identical, this facilitating setting of the loom, improving reliability, reducing the cost price and rendering the mechanism more compact. This is important insofar as a weave system may count more than 10 000 such mechanisms. According to advantageous but non-obligatory aspects of the invention, such a mechanism may incorporate one or more of the following characteristics, taken in any technically possible combination: The blades of a same pair of hooks are adapted to come into abutment against the retaining levers towards their respective retaining noses and to apply these levers towards the electromagnets, during a levelling operation. - Each retaining lever is articulated about a fixed axis with respect to a housing of the mechanism and extends, with respect to this axis, essentially in a direction perpendicular to this axis and on one side thereof. The retaining levers are thus more compact and more robust than the upper levers of EP-A-0 899 367. - The two retaining levers of a same pair are substantially identical, this enabling savings to be made at manufacture and facilitating management of the stock of spare parts. - Each retaining lever is provided with at least one deflector adapted to isolate from the outside a chamber whose volume varies as a function of its angular position. This avoids the accumulation of flock in such a chamber and limits the risks of dysfunction. - The body of the first hook is provided, on a first side, with a nose adapted to come into simple abutment on the corresponding knife and, on a second side opposite the first side, with a heel adapted to receive in simple abutment a part of the body of the second hook. The transmission of effort between the first and the second hook of a pair thus takes place without strain of the flexible blades borne by each of these bodies, the mechanical characteristics of these blades being able to be optimized depending on their respective functions of levelling and/or hooking of the hooks on the retaining levers. In that case, the nose and the heel of the body of the first hook advantageously extend on either side of the flexible blade fixed on this body. - The flexible blades of the mobile hooks of a same pair are of different lengths and guided so that they may bend under similar conditions, this making it possible to apply substantially the same effort on the associated levers during levelling. The invention also relates to a three-position weave system of a Jacquard weaving loom, which comprises at least one selection mechanism as described hereinabove. Such a system is more reliable and more economical than those of the state of the art. Finally, the invention relates to a weaving loom equipped with a weave system as mentioned hereinabove, such a loom being more reliable and easier to use than those of the state of the art. The invention will be more readily understood and other advantages thereof will appear more clearly in the light of the following description of a form of embodiment of a weaving loom, a weave system and a selection mechanism in accordance with its principle, given solely by way of example and with reference to the accompanying drawings, in which: Figure 1 is a longitudinal section through a part of the shed-forming mechanism according to the invention in a first configuration. Figure 1A is a view in detail of the zone of interaction between a mobile hook and a retaining lever, on a larger scale and in the direction of arrow A in Figure 1. Figure 2 is a half-section corresponding to the right-hand part of Figure 1, while the mechanism is in a second configuration, and Figure 3 is a half-section similar to Figure 2, while the mechanism is in a third configuration. The shed-forming mechanism shown in Figures 1 to 3 is intended to be integrated in a three-position weave system mounted on a weaving loom for manufacturing carpets. It makes it possible to control the position of a snap or lower end hook of a harness cord from which one or more heddles is/are suspended. The part of the mechanism shown in the Figures is associated with a plurality of superposed pulleys in accordance with the technical teaching of EP-A-0 839 937, the relative position of the pulleys making it possible to control the height of the snap or end hook mentioned above. In order to control the position of these pulleys of which two are schematically shown solely in Figure 1 with references Pi and P2, two funicular elements 1 and 2 in the form of cords respectively connect two outer mobile hooks 11 and 11' and two inner mobile hooks 12 and 12'. The hooks 11 and 12, on the one hand, and 11' and 12' on the other hand, are provided to be displaced together by a knife 13 or 13', the inner hook of each pair of hooks in that case being in simple abutment on the outer hook of the same pair, and this likewise in accordance with the technical teaching of EP-0-839 937. The mechanism M also comprises two electromagnets 4 and 5 superposed parallel to the direction of an axis Z-Z' which is substantially vertical in Figure 1 and which corresponds to the direction of displacement of the pulleys P1 and P2. The electromagnets 4 and 5 may be selectively activated by a control module (not shown). On either side of the electromagnets 4 and 5 are disposed two pairs of levers 21 and 21', 22 and 22' respectively. Levers 21, 21', 22 and 22' are structurally identical and are each mounted to pivot about a shaft 211,211', 221, 221' respectively, of which the geometric axis X2n, X211', X221, X221 is fixed with respect to a housing 6 of the mechanism immobilised with respect to the structure of the loom. The axes X211 and equivalent are globally perpendicular to axis Z-Z'. The lever 21 comprises an upper eye 212 in which is made an opening for passage of the shaft 211 and essentially extends below the shaft 211 in Figure 1, i.e. in practice downwardly in a direction globally parallel to axis Z-Z'. The lever 21 comprises a metallic armature 213 disposed substantially opposite the electromagnet 4 and which extends in a direction globally parallel to axis Z-Z' and perpendicular to axis X211. The lever 21 is provided with a nose 214 on which may be hooked a part of the mobile hook 11, as will be evident from the following explanations. The lever 21 also bears a deflector 215 which makes it possible to isolate from the outside a chamber C21 whose volume varies as a function of the angular position of the lever 21 about axis X2n. In effect, the lever 21 is mounted to pivot about axis X211 as represented by double arrow F1, the chamber C21 being bordered by the two polar contact surfaces respectively provided on the lever 21 and on the electromagnet 4. The angular position of the lever 21 may be controlled by means of the electromagnet 4 and a compression spring 14 which is interposed between the lever 21 and a central part 6A of the housing 6. The spring 14 exerts on the lever 21 an elastic effort E4 which tends to move the nose 214 away from axis Z-Z'. The levers 21', 22 and 22' are structurally identical to lever 21 and are each provided with a metallic armature 213', 223 and 223', with a retaining nose 214', 224 and 224' and with a deflector 215', 225 and 225' and subjected to the action of a spring 14', 15 and 15'. Likewise, each of the levers 21', 22 and 22' extends in a direction globally parallel to axis Z-Z' with respect to the axes X211, X221 and X221. These levers are mounted to pivot about their respective axes, as represented by arrows F'1, F2 and F'2 and their position may be controlled by the electromagnets 4 or 5 and the springs 14 and equivalent. The axes X211 and X221 are offset parallel to axis Z-Z' by a distance d1 greater than the length of the lever 21. These axes are also offset, in a direction Y-Y' perpendicular to axis Z-Z' and to axes X211 and X221, by a distance d2, axis X211 being further away from axis Z-Z' than axis X221. As the levers 21 and 22 are identical, the noses 214 and 224 are also offset by distances d1 and d2 both parallel to axis Z-Z' and perpendicularly to that axis. The fact that the retaining levers extend on one side only of their respective axes of articulation, makes it possible to obtain fairly easily a good definition of their geometry, this determining the operational reliability of the mechanism M to an important degree. In particular, the inertia of these levers in rotation is relatively low, which makes it possible to use return springs 14 and equivalent, exerting a return effort E4 or equivalent of low intensity and, consequently, electromagnets 4 and 5 which are of relatively low power and therefore compact. The hook 11 is in two parts and comprises a body 111 made of relatively massive synthetic material and in which is moulded an end 112 of a flexible, metallic blade 113 intended to interact with the lever 21. This two-part structure can be compared with that described in EP-A-1 413 657 for a two-position weave system. However, the mechanism of the present invention differs substantially from that prior art by its particular configuration adapted to a three-position weave system. The blade 113 is provided, in the vicinity of its end 114 most remote from the body 111, with an opening 115 for receiving the nose 214 of the lever 21. In this way, as shown to the right in Figure 1, the hook 11 may be retained in position, in the vicinity of the top dead centre of its path, by the lever 21. In the same way, the hook 12 comprises a body 121 made of synthetic material in which is moulded the lower end 122 of a flexible, metallic blade 123 intended to interact on the lever 22. In the vicinity of its upper end 124, the blade is provided with an opening for receiving the nose 224 of the lever 22. It will be noted that the blade 113 is substantially longer than blade 123, which corresponds to the fact that, in the position of retention of the mobile hooks 11 and 12 in the vicinity of the top dead centre of their path, the distance between the body 111 and the nose 214 is substantially greater than the distance between the body 121 and the nose 224. Taking into account their flexibility, the blades 113 and 123 are capable of angular clearance with respect to their zone of attachment on the bodies 111 and 121, as represented by arrows F3. The blades 113 and 123 are each guided in a slideway 116 or 126 formed by the housing 6 and which extends up to the vicinity of the lever 21 or 22. At the same distance d6 from the hooks 214 and 224, the slideways 116 and 126 widen, moving away from axis Z-Z' and rising towards the noses, to allow the flexion of the blades 113 and 123 over the same height, in the vicinity of their respective upper ends 114 and 124. In this way, even if the blades 113 and 123 have different lengths, they bend under similar conditions, this implying that the efforts of levelling exerted on the levers 21 and 22 are substantially identical. When the hook 12 is in abutment on the hook 11, the ends 114 and 124 of the blades 113 and 123 and, in particular, their openings 115 and equivalent, have the same spatial offset as the noses 214 and 224. In other words, the ends 214 and 224 are offset by d1 parallel to Z-Z' and by d2 parallel to Y-Y', which allows them to interact simultaneously with the hooks 214 and 224. The structure of the mobile hooks 11' and 12' is respectively identical to that of the hooks 11 and 12. It is noted that the noses 214 and 224 are directed, with respect to the principal part of the levers 21 and 22, opposite the magnets 4 and 5. In the same way, the noses 214' and 224' are directed opposite the electromagnets. In this way, the blades 113, 123, as well as the corresponding blades 113' and 123' of the mobile hooks 11' and 12', come into contact with the levers 21, 22, 21' and 22' by the outside with respect to the electromagnets 4 and 5, this being particularly advantageous during levelling of the retaining levers, i.e. in the position shown on the left in Figure 1 when the knife 13' displaces the hook 11', with the result that the upper ends 114' and 124' of the blades 113' and 123' push the levers 21' and 22' in the direction of the electromagnets 4 and 5. If one of the other of the electromagnets 4 or 5 is then activated by the control module, the lever or levers 21' and 22' is/are efficiently retained in position substantially applied against the electromagnet(s), this allowing the hook 11' and possibly the hook 12' to redescend in abutment on the knife 13' when the latter starts its downward stroke. Such a configuration is shown on the right in Figure 2 and corresponds to the redescent of the knife 13 after a levelling has been effected as shown on the left of Figure 1. In that case, the electromagnet 4 has been activated while the electromagnet 5 has not been activated, with the result that the nose 224 of the lever 22 which is pushed by the spring 15 has retained in position the blade 123 and consequently the hook assembly 12, while, taking into account the activation of the electromagnet 4, the nose 214 of the lever 21 has been retracted from the path of the blade 113, which allows the hook 11 to redescend in abutment on the knife 13. Like the blades 113 and 123, the blades 113' and 123' are guided in slideways ensuring equality of the efforts of levelling exerted on the levers 21' and 22'. In the configuration of Figure 3, the electromagnets 4 and 5 have been activated, with the result that the noses 214 and 224 of the levers 21 and 22 have been retracted from the paths of descent of the blades 113 and 123 after levelling. In that case, the hooks 11 and 12 redescend with the knife 13, in abutment thereon. The body 111 comprises a nose 111A intended to come into abutment on the knife 13 during the displacements of the hook 11 as well as a heel 11 IB located on that side of the body 111 opposite the nose 111A with respect to the blade 113, this heel 11 IB is intended to receive in simple abutment a heel 12IB formed by the body 121, particularly in the configurations of Figures 1 and 3. In this way, the interaction between the bodies 111 and 121 of the hooks 11 and 12 does not influence that part of these hooks used for retaining them in top position, while such is the case of the equipment known from EP-A-0 839 937 and EP-A-0 899 367. A weave system according to the invention incorporates a plurality of mechanisms such as that described hereinabove and shown in the Figures, in practice one such mechanism per heddle or group of heddles of which the position is to be controlled. A weaving loom according to the invention and provided with one such weave system as mentioned hereinabove may be used for weaving special fabrics, in particular velvet or carpets. It is more economical to purchase and to work, and the risks of defects are reduced. The invention has been shown with two electromagnets 4 and 5 disposed between the levers 21, 21', 22 and 22'. It is also applied to the case of the electromagnets being four in number, one electromagnet being allocated to each lever. Moreover, the blades 113, 113', 123 and 123' are not necessarily metallic. They may be made of a synthetic material presenting mechanical properties adapted to their function, for example carbon fibres or fibre-reinforced plastics material. WE CLAIM: 1. Shed-forming mechanism for three-position weave system of a weaving loom of jacquard type, said mechanism comprising at least two electromagnets, superposed and adapted to be selectively activated, as well as two pair of pivoting retaining levers, the retaining levers of a same pair being arranged on the same side of said electromagnets and each provided with a metallic armature adapted to cooperate with one of said electromagnets and with a nose for retaining a mobile hook belonging to a pair of hooks adapted to be displaced jointly by a knife, characterized in that, within a same pair of mobile hooks (11, 12, 11', 12'), a first hook (11, 11') comprises a body (111) intended to come into simple abutment on said knife (13, 13') as well as a flexible blade (113, 113') intended to interact with a retaining lever (21, 21'), while the second hook (12, 12') comprises a body (121) intended to come into simple abutment on the body of said first hook, as well as a flexible blade (123, 123') intended to interact with the other retaining lever (22, 22') of the same pair of levers, in that each blade is fixed on the corresponding body with possibility of clearance (F3), in that the retaining nose (214, 214', 224, 224') of each retaining lever (21, 21', 22, 22') is made on the side of said lever opposite the associated electromagnet (4, 5), in that the retaining noses of the levers of a same pair of levers are offset (d1, d2) with respect to one another both in a direction (Z-Z') parallel to the direction of displacement of the associated mobile hooks and in a direction (Y, Y') perpendicular to said direction of displacement, and in that those parts (114, 115, 124) of the flexible blades (113, 123, 113', 123') intended to interact with said retaining noses have substantially the same offset (d1, d2) between themselves in said directions when the body of the second mobile hook (12,12') is in abutment on the body of the first mobile hook (11, 11'). 2. Mechanism as claimed in claim 1, wherein said blades (113, 123, 113', 123') of a same pair of hooks (11, 12, 11', 12') are adapted to come into abutment against said retaining levers (21, 21', 22, 22') towards their respective retaining noses (214, 214', 224, 224') and to apply said levers towards said electromagnets. 3. Mechanism as claimed in one of preceding claims, wherein each retaining lever (21, 21', 22, 22') is articulated about an axis (X21, X21', X22, X22) fixed with respect to a housing (6) of said mechanism (M) and extends, with respect to said axis, essentially in a direction (Z-Z') perpendicular to said axis and on one side thereof. 4. Mechanism as claimed in one of preceding claims, wherein, the two retaining levers (21, 22, 21', 22') of a same pair are substantially identical. 5. Mechanism as claimed in one of the preceding claims, wherein, each retaining lever (21, 21', 22, 22') is provided with at least one deflector (215, 215', 225, 225') adapted to isolate from the outside a chamber (C21) whose volume varies as a function of the angular position (F1, F'1, F2, F'2) of said lever. 6. Mechanism as claimed in one of preceding claims, wherein the body (111) of said first hook (11, 11') is provided, on a first side, with a nose (111A) adapted to come into simple abutment on said knife (13, 13') and on a second side opposite the first side, with a heel (111B) adapted to receive in simple abutment a part (12IB) of the body (121) of the second hook (12, 12'). 7. Mechanism as claimed in claim 6, wherein said nose (111 A) and said heel (111B) of the body(lll)ofsaid first hook(ll, 11') extend on either side of the flexible blade (113, 113') fixed on said body. 8. Mechanism as claimed in one of the preceding claims, wherein the flexible blades (113, 123, 113', 123') of the mobile hooks (11, 12, 11', 12') of a same pair of hooks have different lengths and are guided (116, 116' so (d6) that they may bend (F3) under similar conditions. 9. Three-position weave system of a Jacquard weaving loom comprising at least one selection mechanism (M) as claimed in one of the preceding claims. 10. Weaving loom of Jacquard type equipped with a weave system as claimed in claim 9.

Full Text

The present invention relates to shed-forming mechanism, three position weave system and weaving loom equipped with such a system.
The invention relates to a shed-forming mechanism, to a three-position weave system, as well as to a weaving loom equipped with such a weave system.
A weaving loom incorporating a weave system able to generate three positions of the warp yarns is generally used for making special fabrics such as in particular velvet or carpets.
EP-A-0 839 937 discloses a three-position weave system in which mobile hooks are provided to be displaced in pairs by the knives of the system, one hook of each pair being in simple abutment on the second hook of this pair. The hooks are joined in two's by funicular elements and associated with a plurality of pulleys adapted to be spaced apart from one another in variable manner, as a function of the position of these four hooks.
It is also known from EP-A-0 899 367 to provide, in a selection device for a three-position weave system, two pairs of pivoting levers, disposed on either side of two superposed electromagnets, the levers of each pair of levers being able to be controlled by one of the electromagnets and each being provided with a nose for immobilising a mobile hook belonging to a pair of hooks superposed one on the other and adapted to be displaced together by a knife. This device functions correctly but is relatively complex to manufacture insofar as one of the pivoting levers extends on either side of its axis of articulation with an elaborated shape, which increases its cost price accordingly. In addition, flock risks accumulating in the zone provided between each lever and the adjacent part of the electromagnet which serves to control its pivoting which, in the long run, may induce errors of selection which lead to the creation of "defects" on the fabric or carpet in the course of manufacture.
In this known device, the two mobile hooks penetrate in the vicinity of the top dead centre of their path, between the noses of the retaining levers, these
mobile hooks being in practice made of plastics material and having a width which varies as a function of the manufacturing tolerances, differences in width of the mobile hooks being able to lead to an inappropriate positioning of one or the other of the pivoting retaining levers, which, there again, risks inducing "defects" on the fabric or carpet in the course of weaving.
It is a more particular object of the invention to overcome these drawbacks by proposing a shed-forming mechanism intended to be used in a three-position weave system and which is easier to manufacture and use than those of the systems of the state of the art, while its operational reliability is improved.
In this spirit, the invention relates to a shed-forming mechanism for three-position weave system of a weaving loom of Jacquard type, this mechanism comprising at least two electromagnets, superposed and adapted to be selectively activated, as well as two pair of pivoting retaining levers, the retaining levers of a same pair being arranged on the same side of the electromagnets and each provided with a metallic armature adapted to cooperate with one of the electromagnets and with a nose for retaining a mobile hook belonging to a pair of hooks adapted to be displaced jointly by a knife. This mechanism is characterized in that, within a same pair of mobile hooks, a first hook comprises a body intended to come into simple abutment on the knife as well as a flexible blade intended to interact with one of the retaining levers, while the second hook comprises a body intended to come into simple abutment on the body of the first hook, as well as a flexible blade intended to interact with the other retaining lever of the same pair of levers, in that each blade is fixed on the corresponding body with possibility of clearance, in that the retaining nose of each retaining lever is made on the side of the lever opposite the associated electromagnet, in that the retaining noses of the levers of a same pair are offset

with respect to one another both in a direction parallel to the direction of displacement of the associated mobile hooks and in a direction perpendicular to this direction of displacement, and in that those parts of the flexible blades intended to interact with these retaining noses have substantially the same offset between themselves in the two aforementioned directions when the body of the second mobile hook is in abutment on the body of the first.
Thanks to the invention, the flexible blade fixed on the body of each mobile hook is intended to interact with one of the retaining levers of a pair of levers, its geometry being clearly defined as the manufacturing tolerances of a blade may be very precise. On the other hand, the body of each hook, which is advantageously made of synthetic material, may be very solid as it is relatively massive. The flexibility of the blade is used to allow its clearance with respect to the body of each hook, this allowing it to come efficiently into engagement with the corresponding retaining lever, whether it be during levelling of the pivoting levers or for retaining the hook in the vicinity of the top position of its path. As the noses for immobilising the two levers of a same pair are oriented in the same direction, the effort of levelling exerted by the elastic blade on the levers is quite comparable between the two levers and, inversely, the retaining effort exerted by the nose of each lever is quite comparable on the two hooks of a same pair. In addition, the electromagnets, their respective control devices and the associated levers may be substantially identical, this facilitating setting of the loom, improving reliability, reducing the cost price and rendering the mechanism more compact. This is important insofar as a weave system may count more than 10 000 such mechanisms.
According to advantageous but non-obligatory aspects of the invention, such a mechanism may incorporate one or more of the following characteristics, taken in any technically possible combination:

The blades of a same pair of hooks are adapted to come into abutment against the retaining levers towards their respective retaining noses and to apply these levers towards the electromagnets, during a levelling operation.
- Each retaining lever is articulated about a fixed axis with respect to a housing of the mechanism and extends, with respect to this axis, essentially in a direction perpendicular to this axis and on one side thereof. The retaining levers are thus more compact and more robust than the upper levers of EP-A-0 899 367.
- The two retaining levers of a same pair are substantially identical, this enabling savings to be made at manufacture and facilitating management of the stock of spare parts.
- Each retaining lever is provided with at least one deflector adapted to isolate from the outside a chamber whose volume varies as a function of its angular position. This avoids the accumulation of flock in such a chamber and limits the risks of dysfunction.
- The body of the first hook is provided, on a first side, with a nose adapted to come into simple abutment on the corresponding knife and, on a second side opposite the first side, with a heel adapted to receive in simple abutment a part of the body of the second hook. The transmission of effort between the first and the second hook of a pair thus takes place without strain of the flexible blades borne by each of these bodies, the mechanical characteristics of these blades being able to be optimized depending on their respective functions of levelling and/or hooking of the hooks on the retaining levers. In that case, the nose and the heel of the body of the first hook advantageously extend on either side of the flexible blade fixed on this body.
- The flexible blades of the mobile hooks of a same pair are of different lengths and guided so that they may bend under similar conditions, this making

it possible to apply substantially the same effort on the associated levers during levelling.
The invention also relates to a three-position weave system of a Jacquard weaving loom, which comprises at least one selection mechanism as described hereinabove. Such a system is more reliable and more economical than those of the state of the art.
Finally, the invention relates to a weaving loom equipped with a weave system as mentioned hereinabove, such a loom being more reliable and easier to use than those of the state of the art.
The invention will be more readily understood and other advantages thereof will appear more clearly in the light of the following description of a form of embodiment of a weaving loom, a weave system and a selection mechanism in accordance with its principle, given solely by way of example and with reference to the accompanying drawings, in which:
Figure 1 is a longitudinal section through a part of the shed-forming mechanism according to the invention in a first configuration.
Figure 1A is a view in detail of the zone of interaction between a mobile hook and a retaining lever, on a larger scale and in the direction of arrow A in Figure 1.
Figure 2 is a half-section corresponding to the right-hand part of Figure 1, while the mechanism is in a second configuration, and
Figure 3 is a half-section similar to Figure 2, while the mechanism is in a third configuration.
The shed-forming mechanism shown in Figures 1 to 3 is intended to be integrated in a three-position weave system mounted on a weaving loom for manufacturing carpets. It makes it possible to control the position of a snap or lower end hook of a harness cord from which one or more heddles is/are

suspended. The part of the mechanism shown in the Figures is associated with a plurality of superposed pulleys in accordance with the technical teaching of EP-A-0 839 937, the relative position of the pulleys making it possible to control the height of the snap or end hook mentioned above. In order to control the position of these pulleys of which two are schematically shown solely in Figure 1 with references Pi and P2, two funicular elements 1 and 2 in the form of cords respectively connect two outer mobile hooks 11 and 11' and two inner mobile hooks 12 and 12'. The hooks 11 and 12, on the one hand, and 11' and 12' on the other hand, are provided to be displaced together by a knife 13 or 13', the inner hook of each pair of hooks in that case being in simple abutment on the outer hook of the same pair, and this likewise in accordance with the technical teaching of EP-0-839 937.
The mechanism M also comprises two electromagnets 4 and 5 superposed parallel to the direction of an axis Z-Z' which is substantially vertical in Figure 1 and which corresponds to the direction of displacement of the pulleys P1 and P2. The electromagnets 4 and 5 may be selectively activated by a control module (not shown).
On either side of the electromagnets 4 and 5 are disposed two pairs of levers 21 and 21', 22 and 22' respectively. Levers 21, 21', 22 and 22' are structurally identical and are each mounted to pivot about a shaft 211,211', 221, 221' respectively, of which the geometric axis X2n, X211', X221, X221 is fixed with respect to a housing 6 of the mechanism immobilised with respect to the structure of the loom. The axes X211 and equivalent are globally perpendicular to axis Z-Z'. The lever 21 comprises an upper eye 212 in which is made an opening for passage of the shaft 211 and essentially extends below the shaft 211 in Figure 1, i.e. in practice downwardly in a direction globally parallel to axis Z-Z'. The lever 21 comprises a metallic armature 213 disposed substantially

opposite the electromagnet 4 and which extends in a direction globally parallel to axis Z-Z' and perpendicular to axis X211. The lever 21 is provided with a nose 214 on which may be hooked a part of the mobile hook 11, as will be evident from the following explanations.
The lever 21 also bears a deflector 215 which makes it possible to isolate from the outside a chamber C21 whose volume varies as a function of the angular position of the lever 21 about axis X2n. In effect, the lever 21 is mounted to pivot about axis X211 as represented by double arrow F1, the chamber C21 being bordered by the two polar contact surfaces respectively provided on the lever 21 and on the electromagnet 4. The angular position of the lever 21 may be controlled by means of the electromagnet 4 and a compression spring 14 which is interposed between the lever 21 and a central part 6A of the housing 6. The spring 14 exerts on the lever 21 an elastic effort E4 which tends to move the nose 214 away from axis Z-Z'.
The levers 21', 22 and 22' are structurally identical to lever 21 and are each provided with a metallic armature 213', 223 and 223', with a retaining nose 214', 224 and 224' and with a deflector 215', 225 and 225' and subjected to the action of a spring 14', 15 and 15'.
Likewise, each of the levers 21', 22 and 22' extends in a direction globally parallel to axis Z-Z' with respect to the axes X211, X221 and X221. These levers are mounted to pivot about their respective axes, as represented by arrows F'1, F2 and F'2 and their position may be controlled by the electromagnets 4 or 5 and the springs 14 and equivalent.
The axes X211 and X221 are offset parallel to axis Z-Z' by a distance d1 greater than the length of the lever 21. These axes are also offset, in a direction Y-Y' perpendicular to axis Z-Z' and to axes X211 and X221, by a distance d2, axis X211 being further away from axis Z-Z' than axis X221. As the levers 21 and 22

are identical, the noses 214 and 224 are also offset by distances d1 and d2 both parallel to axis Z-Z' and perpendicularly to that axis.
The fact that the retaining levers extend on one side only of their respective axes of articulation, makes it possible to obtain fairly easily a good definition of their geometry, this determining the operational reliability of the mechanism M to an important degree. In particular, the inertia of these levers in rotation is relatively low, which makes it possible to use return springs 14 and equivalent, exerting a return effort E4 or equivalent of low intensity and, consequently, electromagnets 4 and 5 which are of relatively low power and therefore compact.
The hook 11 is in two parts and comprises a body 111 made of relatively massive synthetic material and in which is moulded an end 112 of a flexible, metallic blade 113 intended to interact with the lever 21. This two-part structure can be compared with that described in EP-A-1 413 657 for a two-position weave system. However, the mechanism of the present invention differs substantially from that prior art by its particular configuration adapted to a three-position weave system.
The blade 113 is provided, in the vicinity of its end 114 most remote from the body 111, with an opening 115 for receiving the nose 214 of the lever 21. In this way, as shown to the right in Figure 1, the hook 11 may be retained in position, in the vicinity of the top dead centre of its path, by the lever 21.
In the same way, the hook 12 comprises a body 121 made of synthetic material in which is moulded the lower end 122 of a flexible, metallic blade 123 intended to interact on the lever 22. In the vicinity of its upper end 124, the blade is provided with an opening for receiving the nose 224 of the lever 22.
It will be noted that the blade 113 is substantially longer than blade 123, which corresponds to the fact that, in the position of retention of the mobile

hooks 11 and 12 in the vicinity of the top dead centre of their path, the distance between the body 111 and the nose 214 is substantially greater than the distance between the body 121 and the nose 224.
Taking into account their flexibility, the blades 113 and 123 are capable of angular clearance with respect to their zone of attachment on the bodies 111 and 121, as represented by arrows F3.
The blades 113 and 123 are each guided in a slideway 116 or 126 formed by the housing 6 and which extends up to the vicinity of the lever 21 or 22. At the same distance d6 from the hooks 214 and 224, the slideways 116 and 126 widen, moving away from axis Z-Z' and rising towards the noses, to allow the flexion of the blades 113 and 123 over the same height, in the vicinity of their respective upper ends 114 and 124. In this way, even if the blades 113 and 123 have different lengths, they bend under similar conditions, this implying that the efforts of levelling exerted on the levers 21 and 22 are substantially identical.
When the hook 12 is in abutment on the hook 11, the ends 114 and 124 of the blades 113 and 123 and, in particular, their openings 115 and equivalent, have the same spatial offset as the noses 214 and 224. In other words, the ends 214 and 224 are offset by d1 parallel to Z-Z' and by d2 parallel to Y-Y', which allows them to interact simultaneously with the hooks 214 and 224.
The structure of the mobile hooks 11' and 12' is respectively identical to that of the hooks 11 and 12.
It is noted that the noses 214 and 224 are directed, with respect to the principal part of the levers 21 and 22, opposite the magnets 4 and 5. In the same way, the noses 214' and 224' are directed opposite the electromagnets. In this way, the blades 113, 123, as well as the corresponding blades 113' and 123' of the mobile hooks 11' and 12', come into contact with the levers 21, 22, 21' and 22' by the outside with respect to the electromagnets 4 and 5, this being

particularly advantageous during levelling of the retaining levers, i.e. in the position shown on the left in Figure 1 when the knife 13' displaces the hook 11', with the result that the upper ends 114' and 124' of the blades 113' and 123' push the levers 21' and 22' in the direction of the electromagnets 4 and 5. If one of the other of the electromagnets 4 or 5 is then activated by the control module, the lever or levers 21' and 22' is/are efficiently retained in position substantially applied against the electromagnet(s), this allowing the hook 11' and possibly the hook 12' to redescend in abutment on the knife 13' when the latter starts its downward stroke.
Such a configuration is shown on the right in Figure 2 and corresponds to the redescent of the knife 13 after a levelling has been effected as shown on the left of Figure 1. In that case, the electromagnet 4 has been activated while the electromagnet 5 has not been activated, with the result that the nose 224 of the lever 22 which is pushed by the spring 15 has retained in position the blade 123 and consequently the hook assembly 12, while, taking into account the activation of the electromagnet 4, the nose 214 of the lever 21 has been retracted from the path of the blade 113, which allows the hook 11 to redescend in abutment on the knife 13.
Like the blades 113 and 123, the blades 113' and 123' are guided in slideways ensuring equality of the efforts of levelling exerted on the levers 21' and 22'.
In the configuration of Figure 3, the electromagnets 4 and 5 have been activated, with the result that the noses 214 and 224 of the levers 21 and 22 have been retracted from the paths of descent of the blades 113 and 123 after levelling. In that case, the hooks 11 and 12 redescend with the knife 13, in abutment thereon.

The body 111 comprises a nose 111A intended to come into abutment on the knife 13 during the displacements of the hook 11 as well as a heel 11 IB located on that side of the body 111 opposite the nose 111A with respect to the blade 113, this heel 11 IB is intended to receive in simple abutment a heel 12IB formed by the body 121, particularly in the configurations of Figures 1 and 3. In this way, the interaction between the bodies 111 and 121 of the hooks 11 and 12 does not influence that part of these hooks used for retaining them in top position, while such is the case of the equipment known from EP-A-0 839 937 and EP-A-0 899 367.
A weave system according to the invention incorporates a plurality of mechanisms such as that described hereinabove and shown in the Figures, in practice one such mechanism per heddle or group of heddles of which the position is to be controlled.
A weaving loom according to the invention and provided with one such weave system as mentioned hereinabove may be used for weaving special fabrics, in particular velvet or carpets. It is more economical to purchase and to work, and the risks of defects are reduced.
The invention has been shown with two electromagnets 4 and 5 disposed between the levers 21, 21', 22 and 22'. It is also applied to the case of the electromagnets being four in number, one electromagnet being allocated to each lever.
Moreover, the blades 113, 113', 123 and 123' are not necessarily metallic. They may be made of a synthetic material presenting mechanical properties adapted to their function, for example carbon fibres or fibre-reinforced plastics material.

WE CLAIM:
1. Shed-forming mechanism for three-position weave system of a weaving loom of jacquard
type, said mechanism comprising at least two electromagnets, superposed and adapted to be selectively activated, as well as two pair of pivoting retaining levers, the retaining levers of a same pair being arranged on the same side of said electromagnets and each provided with a metallic armature adapted to cooperate with one of said electromagnets and with a nose for retaining a mobile hook belonging to a pair of hooks adapted to be displaced jointly by a knife, characterized in that, within a same pair of mobile hooks (11, 12, 11', 12'), a first hook (11, 11') comprises a body (111) intended to come into simple abutment on said knife (13, 13') as well as a flexible blade (113, 113') intended to interact with a retaining lever (21, 21'), while the second hook (12, 12') comprises a body (121) intended to come into simple abutment on the body of said first hook, as well as a flexible blade (123, 123') intended to interact with the other retaining lever (22, 22') of the same pair of levers, in that each blade is fixed on the corresponding body with possibility of clearance (F3), in that the retaining nose (214, 214', 224, 224') of each retaining lever (21, 21', 22, 22') is made on the side of said lever opposite the associated electromagnet (4, 5), in that the retaining noses of the levers of a same pair of levers are offset (d1, d2) with respect to one another both in a direction (Z-Z') parallel to the direction of displacement of the associated mobile hooks and in a direction (Y, Y') perpendicular to said direction of displacement, and in that those parts (114, 115, 124) of the flexible blades (113, 123, 113', 123') intended to interact with said retaining noses have substantially the same offset (d1, d2) between themselves in said directions when the body of the second mobile hook (12,12') is in abutment on the body of the first mobile hook (11, 11').
2. Mechanism as claimed in claim 1, wherein said blades (113, 123, 113', 123') of a same
pair of hooks (11, 12, 11', 12') are adapted to come into abutment against said retaining levers (21, 21', 22, 22') towards their respective retaining noses (214, 214', 224, 224') and to apply said levers towards said electromagnets.
3. Mechanism as claimed in one of preceding claims, wherein each retaining lever (21, 21',
22, 22') is articulated about an axis (X21, X21', X22, X22) fixed with respect to a housing (6) of said mechanism (M) and extends, with respect to said axis, essentially in a direction (Z-Z') perpendicular to said axis and on one side thereof.
4. Mechanism as claimed in one of preceding claims, wherein, the two retaining levers (21,
22, 21', 22') of a same pair are substantially identical.
5. Mechanism as claimed in one of the preceding claims, wherein, each retaining lever (21,
21', 22, 22') is provided with at least one deflector (215, 215', 225, 225') adapted to isolate from the outside a chamber (C21) whose volume varies as a function of the angular position (F1, F'1, F2, F'2) of said lever.
6. Mechanism as claimed in one of preceding claims, wherein the body (111) of said first
hook (11, 11') is provided, on a first side, with a nose (111A) adapted to come into simple abutment on said knife (13, 13') and on a second side opposite the first side, with a heel (111B) adapted to receive in simple abutment a part (12IB) of the body (121) of the second hook (12, 12').
7. Mechanism as claimed in claim 6, wherein said nose (111 A) and said heel (111B) of the
body(lll)ofsaid first hook(ll, 11') extend on either side of the flexible blade (113, 113') fixed on said body.
8. Mechanism as claimed in one of the preceding claims, wherein the flexible blades (113,
123, 113', 123') of the mobile hooks (11, 12, 11', 12') of a same pair of hooks have different lengths and are guided (116, 116' so (d6) that they may bend (F3) under similar conditions.
9. Three-position weave system of a Jacquard weaving loom comprising at least one
selection mechanism (M) as claimed in one of the preceding claims.
10. Weaving loom of Jacquard type equipped with a weave system as claimed in claim 9.

Documents:

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Patent Number

270419

Indian Patent Application Number

1776/DEL/2005

PG Journal Number

52/2015

Publication Date

25-Dec-2015

Grant Date

21-Dec-2015

Date of Filing

07-Jul-2005

Name of Patentee

STAUBLI LYON

Applicant Address

31 RUE DES FRERES LUMIERE, F-69680 CHASIEU, FRANCE.

Inventors:

#	Inventor's Name	Inventor's Address
1	DARIO BASSI	CHEMIN DES SABLES, F-69970 CHAPONNAY, FRANCE.
2	ALEXIS PORTE	PLACE DE LA MAIRIE, F-38230 TIGNIEU JAMEYZIEU, FRANCE.

PCT International Classification Number

D03C 3/24

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	0407980	2004-07-19	France