Abstract:
A shed forming device for a weaving machine includes at least one rotary electric actuator for winding, around a pulley, a funicular element controlling at least one heddle and wherein an output shaft of the actuator rotates around a first axis and wherein the output shaft is provided with a pinion meshing with a toothed crown secured to the pulley and rotatable therewith around a second axis perpendicular to the first axis.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a shed forming device designed to be installed on a weaving machine. 
     2. Brief Description of the Related Art 
     In the textile field, it is known that, on a Jacquard-type weaving machine, the formation of the weaving shed for the warp yarns of the weaving machine takes place by passing each warp yarn through the eyelet of a heddle whereof one end is connected to a spring and the other end is connected to a funicular element. The funicular element or harness is a yarn, a single- or multi-strand cable that can be wound around the pulley and follow a path defined by guide members. The principle of winding the harness around the pulley is known, for example from WO-A-4 433 704 or from EP-A-0 933 456. In the equipment of U.S. Pat. No. 4,433,704, a mechanical shaft drives some pulleys for winding the funicular elements, without use of a rotary electric actuator. In the equipment of EP-A-0 933 456, the pulley is driven by an electric actuator that controls the travel of the harness secured to the pulley. It is also known from EP-A-0 926 280 to use housings comprising up to sixteen subassemblies formed by a pulley and an associated actuator. The housings grouping together these subassemblies have the advantage of saving space on the weaving machine. Up to forty of these housings are assembled on either side of an aluminum profile that ensures their mechanical support and cooling. Each actuator commands a pulley that is removably assembled. The set of the pulleys, harnesses, heddles, springs and associated guide elements requires a significant number of assembly operations. EP-A-1 493 857 discloses a method and a device making it possible to place and disassemble sixteen pulleys from a housing simultaneously. These devices significantly improve the quality of maintenance operations, in terms of practicality and length. 
     The size of a weaving machine is the result of a compromise between cost and bulk imperatives, taking into account the diversity of the applications that may be involved. In parallel, the development of new weaving techniques, such as 3D weaving, requires both an increase in travel and admissible loads on the driving means of the harnesses of the weaving machine of the Jacquard type. 
     SUMMARY OF THE INVENTION 
     The invention more particularly aims to meet these objectives by proposing a new weaving shed device for a weaving machine that is easy and cost-effective to manufacture and allows a significant increase in the travel and admissible loads on the driving means of a harness. 
     To that end, the invention relates to a shed forming device for a weaving machine comprising at least one rotary electric actuator provided for winding around a pulley of the funicular element controlling at least one heddle, an output shaft of the actuator rotating around a first axis. According to the invention, the shaft of the actuator is provided with a pinion, meshing with a toothed crown secured to the pulley and rotatable therewith around a second axis perpendicular to the first axis. 
     Owing to the invention, the maximum available load at the funicular element may be increased by acting on the gear ratio formed by the pinion and the crown. Furthermore, since the pulley rotates around an axis perpendicular to the axis of rotation of the shaft of the motor, it may be supported at both ends thereof without being cantilevered. Its axial length may thus be relatively significant, which allows winding of the funicular element over a number of revolutions allowing a relatively significant travel of the heddle. 
     According to advantageous, but optional aspects of the invention, such a device may incorporate one or more of the following features, considered in any technically admissible combination:
         The crown is movable along the second axis and the device comprises means elastically forcing the crown toward the pinion, along the second axis.   The shaft of the actuator and the axis of the pulley are concurrent.   The pinion has a straight toothing and the crown has a toothing adapted to that of the pinion.   The actuator is mounted in a housing, while the pulley and the crown are rotatably mounted around the second axis in a holder that is separate and separable from the housing.   The device comprises several actuators mounted in a same housing, with their first respective axes parallel to each other, and several subassemblies each comprising a pulley and a crown, in a number equal to the number of actuators mounted in the housing, said subassemblies being mounted in the same holder separate and separable from the housing, with their second respective axes of rotation perpendicular to the first axes of the actuators.   The crown and the pulley are rotatably mounted around a shaft aligned along the second axis and clipped on the holder.   The means for elastically forcing the crown toward the pinion act between the shaft and the holder.   The number of teeth of the pinion is smaller than the number of teeth of the crown.   The crown is clipped and immobilized in rotation, by cooperation of shapes on the pulley.       

     The invention also relates to a weaving machine comprising a weaving shed device as described above. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be better understood and other advantages thereof will appear more clearly in light of the following description of one embodiment of a weaving shed device and weaving machine according to its principle, provided solely as an example and done in reference to the appended diagrammatic drawings, in which: 
         FIG. 1  is a perspective view of a weaving machine of the Jacquard type according to the invention; 
         FIG. 2  is an exploded perspective view of a module belonging to the weaving shed device of the weaving machine of  FIG. 1 , which itself is according to the invention; 
         FIG. 3  is an exploded perspective view of certain elements of the module of  FIG. 2 ; 
         FIG. 4  is an exploded perspective view, from another angle, of the pulley and the crown shown in  FIG. 3 ; 
         FIG. 5  is a perspective view of detail V in  FIG. 2 , enlarged from another angle; 
         FIG. 6  is a perspective view along arrow VI in  FIG. 5 , 
         FIG. 7  is a longitudinal cross-sectional view along the shaft of a pulley subassembly, in a plane similar to plane VII in  FIG. 6 , but in a central part of the holder shown in  FIG. 2 , and 
         FIG. 8  is a front view of the part of the device shown in  FIG. 6 , showing a harness card wound on the pulley. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The Jacquard-type weaving machine M shown in  FIG. 1  comprises a weaving shed forming device  1  mounted on a superstructure  2 , above the beam roll  3  and the cloth beam  4  of the machine on which a fabric T being woven is wound. The device  1  comprises several modules  10  designed to control the vertical movement of harness cords  20  making up the funicular elements of a heald frame  30  of the weaving machine M, each harness cord supporting a heddle  21  equipped with an eyelet  22  for the passage of a warp yarn. Only one column of housings  10 , five harness cords  20  and five heddles  21  are shown in  FIG. 1 , for clarity of the drawing. Each module  10  is positioned on a rail  5 . The shed device  1  comprises twelve rails, each of said rails being able to receive up to forty of said modules on either side. On each of the rails shown in  FIG. 1 , only the first module of each rail is shown. 
     Each of the modules  10  comprises a housing  110  provided to receive sixteen actuators  112  in individual housings  110 A. The output shaft  114  of each of the actuators  112  is secured in rotation to a pinion  116  with a straight toothing. X 114  denotes the axis of rotation of the shaft  114  and the pinion  116  of the actuator  112 . The axes X 114  of the actuators  112  mounted in the housing  110  are parallel to each other. 
     Each actuator  112  is provided to drive a pulley  126  to which the upper end of a harness cord  20  is fastened. To that end, and as shown in  FIG. 3 , each pulley  126  is provided with a housing  126 A for receiving and jamming an upper end (not shown) of the harness cord  20 . Alternatively, the upper end of the harness cord  20  may be overmolded in the pulley. Each pulley  126  also comprises a cylindrical portion  126 B with a circular cross-section on which a harness cord  20  can be wound whereof the end is jammed at the housing  126 A. Y 126  denotes the central axis of the portion  126 B, which is in fact the axis of rotation of the pulley  126 . L 126  denotes the axial length, measured parallel to the axis Y 126 , of the portion  126 B, i.e., the portion of the pulley  126  available for winding a harness cord. 
     Each pulley  126  is secured in rotation, around the axis Y 126 , with a toothed crown  124 . Each pair consisting of a crown  124  and a pulley  126  is mounted in a housing  120 A defined by a holder  120  that is attached on the housing  110 . 
     The holder  120  is open on the first side thereof turned toward the housing  110 , to allow the insertion of the pinion  116  in each housing  120 A. The holder  120  is also open on the second side thereof opposite the housing  110  and visible in  FIG. 2 . On the second side, the holder  120  is obstructed by a cover  130 . 
     The parts  120  and  130  are advantageously made from a plastic material, for example an ABS polycarbonate alloy, that is particularly suitable due to its dimensional stability. 
     The holder  120  is reversibly mounted on the housing  110 , for example using screws (not shown). Likewise, the cover  130  is reversibly mounted on the holder  120 , for example clipped thereon. 
     In the mounted configuration of the module  10 , each pinion  116  of the actuator  112  is engaged with a crown  124 , which in turn is secured to a pulley  126 , while the axes of rotation X 114  and X 126  of said parts are perpendicular. 
     The placement of a pinion  116  and a crown  124  as intermediate parts between the actuator  112 , which generates the rotating movement of the pulley  126 , and the pulley  126 , on which the harness cord  20  is wound, allows the creation of a reduction gear. The number of teeth of the pinion  116  is smaller than the number of teeth of the crown  124 . This makes it possible to obtain a gear reduction effect of the torque obtained at the shaft  114  and which is transmitted to the pulley  126  by the reduction gear formed by the parts  116  and  124 . By acting on the ratio of the torque from the gear made up of the pinion  116  and the crown  124 , the maximum available load at the harness cord  20  may thus be adapted to the tractive forces to be generated on each harness cord  20 . 
     The ratio of the number of teeth of the crown  124  to the number of teeth of the pinion  116  is ⅓ in the chosen embodiment and may be comprised between ½ and ⅕. 
     The pinion  116  has a straight toothing and cooperates with the crown  124 , the toothing of which is adapted to that of the pinion. In practice, the toothing of the crown is of the “Cylkro” type, as known from WO-A-96/12585. In the example of the device considered an shown in  FIGS. 1 to 8 , the pinion has eleven teeth with module  0 . 7 , while the crown has thirty-three teeth. The use of the straight toothing enables relatively imprecise positioning of the crown  124  along the axis X 114 . In fact, the contact conditions remain the same along a tooth of the pinion. Furthermore, the meshing does not generate any resultant on the pinion oriented along the axis X 114 . The meshing therefore has no consequence on the operating conditions of the bearings of the shaft of the actuator. 
     The pinion and the crown are made from polyacetal, the choice of this plastic material allowing operation without adding lubricant and guaranteeing good resistance to wear. 
     The crown  124  and the pulley  126  are mounted freely rotating, with the interposition of a ball bearing  122 , around a shaft  128  whereof the longitudinal axis is aligned with the axis Y 126 . Since the axes X 114  and Y 126  are perpendicular, the shaft  128  extends between two walls  1201  of the holder  120  that are vertical in  FIG. 2 , while the axes X 114  and Y 126  are horizontal. 
     A housing  1244  of the crown  124  is provided to receive a nose  1264  of the pulley  126 . The housing  1244  and the nose  1264  have complementary and noncircular shapes. Thus, the assembly of the pulley  126  on the crown  124  ensures rotational securing with axis Y 126  of the crown and the pulley, by cooperation of shapes. 
     Furthermore, the pulley  126  is mounted on the crown  124  by clipping the nose  1264  of the pulley  126  in the housing  1244 , using elastically deformable tongues  1262  provided with end beaks  1266 . The beaks  1266  of the tongues  1262  are clipped in slits  1242  of the crown  124  provided to that end, on either side of the housing  1244 . This clipping of the pulley  126  on the crown  124  thereby ensures that they are translatably secured along the axis Y 126 . 
     A spring  123  is positioned between the shaft  128  and a wall  1201  of the holder  120 . It exerts an elastic force E 1  on said shaft oriented toward the other wall  1201  of the housing  120 A in which said shaft is received. 
     A pulley subassembly  129  is considered comprising a pulley  126 , a crown  124 , a ball bearing  122 , a spring  123  and a shaft  128 . Each subassembly  129 , whereof the shaft  128  is the central member, is positioned in a housing  120 A of the holder  120 . 
     In the normal usage configuration, one end  123 A of the spring bears against the wall  1201  of the holder  120 , while the other end  123 B is in contact with the bottom of an inner bore  1281  of the shaft  128 . The spring  123  thus exerts the elastic force E 1  on the shaft  128 . The ball bearing  122  resting on a shoulder  1286  of the shaft  128 , the shaft also exerts a force E 1  on the ball bearing  122 , which in turn exerts that force E 1  on the pulley  126 , at an inner shoulder  1268  of the pulley. 
     The use of an elastic forcing means such as the spring  123  makes it possible to react the meshing play between the pinion  116  and the crown  124 , along the axis Y 126 , the crown being elastically recalled toward the pinion. 
     It is possible to clip the ends  1282  and  1284  of the shaft  128  in housings  1204  and  1206  formed in the walls  1201  and provided to that end. The ends  1282  and  1284  have a noncircular cross-section and the housings  1204  and  1206  have geometries compatible with the placement of the ends  1282  and  1284  and with blocking thereof in rotation around the axis Y 126 . Furthermore, each housing  1204  is bordered by an elastically deformable tooth  1205  that serves as a retaining member for the end  1282  of the shaft  128  placed in the housing  1204 . This tooth retracts during the placement of the shaft  128  in the housing  1204 , after which the shaft  128  is clipped and kept in place by the tooth  1205 . A similar tooth is provided at the housing  1206 , such that the end  1284  of the shaft  128  is kept in place. Alternatively, another clipping member, or more generally retaining member, may be provided at the housings  1204  and  1206 . 
     The shaft  128  thus clipped is immobilized in rotation on the axis Y 126  and has a certain axial freedom. The pulley  126 , whereof the shaft is maintained at both ends by the holder  120 , is stable on its axis since it is not cantilevered. Furthermore, it rotates around the shaft  128  by means of two bearings made up on the one hand of the ball bearing  122  and on the other hand of a smooth contact area S between the inner bore of the pulley  124  and the outer cylindrical surface of the shaft  128  situated opposite the ball bearing  122 . The two bearings are located on either side of the winding portion  126 B of the harness cord  20 . It thus becomes possible to increase the length L 126  of the portion  126 B receiving the harness cord  20 , without decreasing the stability of the pulley. In practice, the length L 126  is comprised between 8 and 10 mm for a pulley  126  where of the portion  126 B has a diameter of approximately 9 mm. Under these conditions, the winding length of the harness cord  20  in the configuration of  FIG. 8  has a value comprised between 270 and 290 mm. 
     The length L 126  is increased with respect to the axial length of the pulleys of the prior devices. This increased length makes it possible to wind a more significant harness length around the pulley. This thereby makes it possible to increase the possible travel for the heddles  21 , with respect to the known devices. In particular, the multilayer 3D weaving applications that involve forming several superimposed sheds or moving the shed along the woven layer are easily achievable. 
     The device reacting play along the axis Y 126 , owing to the spring  123 , previously described operates identically for the sixteen pulley subassemblies  129  contained by the holder  120 . In particular, it enables individual self-adjustment of the axial position along the axes Y 126  of the sixteen crowns  124  of the pulley subassemblies  129  mounted on the holder  120 , with respect to the sixteen pinions  116  of the actuators  112  mounted on the housing  110 , when the holder  120  is attached on the housing  110 . 
     According to one very advantageous aspect of the invention, the axes X 114  and Y 126  are concurrent. Thus, the distribution of the assembly tolerances of the pinions  116  and the pulley subassemblies  129  is centered on a nominal configuration where said axes are in fact secant. Thus, in the event of variation of the position of said axes, the toothings of the elements  116  and  124  remain engaged, under satisfactory meshing conditions. In other words, due to the concurrent nature of the axes X 114  and Y 126 , the reduction gear formed by the elements  116  and  124  is not particularly sensitive to positioning flaws along the axis Z perpendicular to the axes X 114  and Y 126  that are distributed on either side of the nominal configuration where said axes are in fact concurrent. 
     Alternatively, these axes may not be concurrent, which is possible in light of the types of toothing used. 
     In this way, the positioning of the crown  124  and the axis of the actuator X 114  does not need to be precise. The device is therefore compatible with an assembly without minute adjustment. The design of the device makes it possible to adapt the meshing conditions in the directions of the axes X 114  and Y 126 , as well as an allowance in direction Z. 
     The pulley subassemblies  129  are supported by the holder  120 , which is a separate part from the housing  110 . In this way, the sixteen subassemblies  129  and their holder  120  make up a removable functional unit that is easy to disassemble to perform maintenance operations both on the actuators  112  and the pulley subassemblies  129 . The assembly of a weaving shed device according to the invention is done by equipping each housing  110  with actuators  112  mounted in the housing  110 A. A pinion  116  is mounted on the shaft  114  of each actuator  112  before or after assembly thereof in the housing  110 . Then, the holder  120  equipped with the pulley subassemblies  129  is attached on the housing  110 . Next, the cover  130  is mounted on the holder  120 . 
     During the placement of the holder  120  on the housing  110 , the crowns  124  come into contact with the end bevel of the teeth of the pinions  116 , then shift along the axis of the pulley  126  shaft Y 126  against the action of the spring  123 . The spring returns the toothings to the meshing configuration, without action by the operator. Once in place, the pinions  116  and crowns  124  are in operating condition, without play and without a specific adjustment operation being necessary. 
     The installation of such a device also makes it possible to recondition a weaving machine from the state of the art into a weaving machine according to the invention. In practice, the transition from a simple cantilever pulley system to a gear system may include the following three steps. First, and for each actuator, the pulley is replaced by a pinion  116 . Then, the holder  120  is mounted on the housing  110  and the cover on the holder, as explained above. 
     Alternatively, the invention may be implemented with conical gears. These gears with concurrent axes require, to operate under optimal conditions, that the apices of the toothing cones coincide. The device for reacting the play along the axis of rotation of the pulley enables a satisfactory adjustment of the play. 
     The invention may also be implemented with hypoid gears, i.e., with left spiral gears. The pinions and crowns have conical teeth, but do not necessarily rotate around concurrent axes.