Abstract:
Springs associated with a harness of a weaving loom of the Jacquard type are connected on a frame of the loom by an assembly of devices each of which includes a plurality of rods each being connectable with a spring and which rods extend from a common base. Each base is provided with hooks adapted to engage with beaks of corresponding shape for mounting each device on at least one elongated section secured to the frame of the loom.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a device for connecting springs associated with a harness of a weaving loom of the Jacquard type on a frame of such a loom, to a connection assembly comprising such a device, and to a weaving loom of the Jacquard type incorporating such an assembly. 
     2. Description of Related Art 
     Each hook of a Jacquard system is known to be associated with one or more cords, the cords together constituting the harness of the system. Each cord is connected to the upper end of a heddle provided with a mail for controlling the position of a warp yarn of the loom in a substantially vertical direction. The lower end of each heddle is connected to an anchoring point, fixed with respect to the frame of the loom, by a spring exerting an elastic return force on the heddle. 
     EP-A-0 678 603, for example, discloses providing a device for connecting the lower end of a helical spring and the frame of a loom by means of a threaded joining piece intended to be screwed in the coils or turns of the spring and comprising two elastic branches adapted to cooperate with the coils or turns of the spring to generate friction to avoid resonance of the latter. This document provides an individual fixation of the connection device on the frame by means of a joining piece in the form of a harpoon, which involves long and fastidious manipulations and accordingly renders the equipping of a weaving loom of Jacquard type with devices of this type more expensive. In case of dismantling, each joining piece must be dismantled individually and it is not rare for joining pieces to deteriorate. 
     It is known, for example by DE-U-86 09665, to group together connection devices on a base extending in a rod provided with a head in the form of a harpoon for hooking thereof on a harness board. Such devices are difficult to unhook and their density of implantation, in particular on an elongated section, cannot be high. 
     It could be envisaged to group together the connection devices, for example in series of four on a base presenting a central orifice in which is introduced a bar supported above the frame. Although presenting advantages over the known art of EP-A-0 678 603, this system and the known one of DEU-86 09665 involve removing a large number of devices from the bar in order to have access to a device having to be changed during a maintenance operation, which proves to be long, fastidious and expensive due to the need for highly qualified manpower. Similarly, it is a complex operation to assemble a weaving loom incorporating this device. In addition, flock tends to accumulate between the devices of this type and it is delicate to clean them. 
     It is a particular object of the present invention to overcome these drawbacks by proposing a spring connection device which comprises a plurality of rods each equipped with means for connection with a spring and extending from a common base. 
     SUMMARY OF THE INVENTION 
     According to the invention, such a device is characterized in that the base is provided with hooks each adapted to cooperate with a beak of corresponding shape for elastic hooking and unhooking of this device on and from at least one elongated section. 
     Thanks to the invention, the fastening formed by the base and the different rods that it supports may be installed on the section particularly rapidly and dismantled equally rapidly, without requiring concomitant assembly or dismantling of the adjacent fastenings. The different rods of a device may be mounted and dismantled in groups with respect to the weaving loom. The flexible hooks and the beaks allow rapid elastic hooking and unhooking on or from the elongated sections. 
     According to advantageous but non-compulsory aspects of the invention, the device incorporates one or more of the following characteristics: 
     The base is substantially planar and adapted to be arranged in a direction substantially perpendicular to a longitudinal direction of the section. The planar nature of the base makes it possible to juxtapose the fastenings in the longitudinal direction of the section with a higher density of the rods intended to cooperate with the springs of the harness. All the springs of the same column located in the harness board depth may be provided to be grouped together on the same fastening disposed in the direction of advance of the warp yarns, while the section extends in a direction substantially parallel to the weft yarns. 
     The rods are juxtaposed essentially along a principal plane of the base. In other words, the rods form a substantially planar lap extending the base. 
     The base is pierced with a central orifice constituting a handle for gripping the device, for example for positioning it on a section. 
     The hooks and the beaks are oriented so that their respective contact surfaces are included in the thickness of the base, which makes it possible to juxtapose the bases, and consequently the rods, with a high density. 
     The base comprises at least one maneuvering element defining a zone of reception of part of a tool for unhooking the device with respect to the elongated section. 
     The device comprises at least one positioning tongue adapted to cooperate with a guiding member secured to the elongated section. This tongue and member make it possible to arrange the different devices with a predetermined pitch defined by this member. 
     The invention also relates to an assembly for connection of the springs of harness of Jacquard type, which comprises a plurality of devices as described hereinbefore and at least one elongated section fast with the frame of the loom and defining, in a transverse section, at least one beak adapted to cooperate with the hooking means provided on these devices. In addition, at least one spacer bar may be provided to be immobilized on the section and presenting zones for receiving part of the bases of these devices, with a predetermined spaced apart relationship in the longitudinal direction of the section. 
     Finally, the invention relates to a weaving loom of Jacquard type comprising an assembly as described hereinbefore. Such a weaving loom is relatively easy to assemble and maintain, while being as efficient as the known looms and its cost price and maintenance costs being substantially lower than known looms. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be more readily understood on reading the following description of two embodiments of a connection device in accordance with its principle, given solely by way of example and made with reference to the accompanying drawings, in which: 
     FIG. 1 schematically shows the lower part of a weaving loom in the course of being equipped with a spring connection assembly according to the invention. 
     FIG. 2 is a section along line II—II in FIG.  1 . 
     FIG. 3 is a view on a larger scale of detail III in FIG.  2 . 
     FIG. 4 is a view on a larger scale of detail IV in FIG.  2 . 
     FIG. 5 is a view on a larger scale of detail V in FIG. 2, and 
     FIG. 6 is a front view of a device in accordance with a second embodiment of the invention. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring now to the drawings, the assembly  1  shown in FIGS. 1 and 2 comprises two rails  2  and  3  formed by aluminium sections and mounted on the lower frame  4  of a weaving loom thanks to a plurality of threaded rods of which only one has been shown in FIGS. 1 and 2 with reference  5 . The frame  4  is sometimes called the “floor” of the loom, the term frame meaning that the element  4  is a fixed part belonging to the structure of the loom. Each threaded rod  5  is associated with plates  6  forming clamps for tightening and immobilizing the lower flanges  2   a  and  3   a  of the rails  2  and  3 . Rails  2  and  3  extend in a direction X-X′ substantially perpendicular to the direction Y-Y′ of advance of the warp yarns in the loom, direction X-X′ thus being substantially parallel to the direction of introduction of the weft yarns in the shed. 
     Spacer members are arranged between the rails  2  and  3 , enabling their spaced apart relationship to be maintained at a substantially constant value. Only one spacer member  7  is visible, but the spacer members are distributed over the whole length of the rails  2  and  3 . Screws  8  cooperate with captive nuts  9  distributed over the length of the rails or sections  2  and  3  in order to immobilize these sections with respect to the spacer members  7  and equivalent. 
     The upper part  2   b  of the rail  2  constitutes an elongated section formed by two branches  21  and  22  defining therebetween a longitudinal channel  23 . The outer branch  21  is provided with a longitudinal groove  21   a , while the inner branch  22  is provided with a longitudinal groove  22   a . The terminal part  22   b  of the branch  22  forms a beak or hook oriented outwardly of the space defined between the rails  2  and  3 . 
     Similarly, the upper part  3   b  of the rail  3  constitutes an elongated section formed by two branches  31  and  32  defining therebetween a channel  33 , these ranches  31  and  32  each being provided with a longitudinal groove  31   a ,  32   a , respectively, while the branch  32  forms a beak or hook  32   b  in its terminal part. 
     A plurality of fastenings  40  are distributed over the assembly formed by the two rails  2  and  3  in the direction X-X′, cooperating with the sections  2   b  and  3   b . Each fastening  40  is formed by a base  41  and by thirty-two rods  42  of which the free, or upper, end  42   a  is provided to engage in the inner volume of a spring  50  of helical type. Only one spring  50  has been shown in the Figures, but each rod  42  is provided to cooperate with a spring. 
     The end  42   a  of each rod  42  is provided with a thread  43  adapted to cooperate with the turns of the corresponding spring  50  and with two divergent branches  44  intended to rub against the inner surface of the spring  50 . Other geometries may be envisaged for the connection means  43  and  44  provided at the end  42   a  of each rod  42 , in accordance with the respective technical teachings of FR-A-2 766 501 and EP-A-0 678 603, or with other approaches. 
     The base  41  and the rods  42  consist of a single piece made by injection-molding of plastics material, such as polyamide (PA) or polyoxymethylene (POM). 
     The base  41  is substantially planar. The plane of symmetry of each fastening  40  is also the plane symmetry of the base  41  and of the rods  42  of such a fastening. The thickness e of each base  41  perpendicularly to its plane of symmetry is relatively small, i.e., less than 5 mm and preferably of the order of 2 mm. 
     The upper edge  411  of the base  41  is substantially rectilinear and perpendicular to the rods  42 . 
     The lower edge  412  of the base  41  is rounded and convex, with the result that it may be engaged between the branches  22  and  32 , above the spacer members  7 , the material constituting the base  41  providing the fastening  40  with sufficient rigidity. In its central part, the base  41  is pierced with an orifice  413  constituting a handle for gripping the fastening  40 , in particular when the springs  50  are positioned on the ends  42   a  of the rods  42 . 
     The base  41  also bears two elastic hooks  414  and  415  intended to cooperate with the beaks or hooks  22   b  and  32   b  of the branches  22  and  32  for an elastic hooking of each fastening  40  on the sections  2   b  and  3   b . Elastic hooking can be obtained thanks to the elastically deformable nature of the hooks  414  and  415  which are made of plastics material since they are in one piece with the base  41 . 
     The geometry of the hooks  414  and  415  and of the beaks  22   b ,  32   b  is such that the contact surfaces  414   a ,  22   c ,  415   a  and  32   c  of these hooks and beaks are located in the thickness of the base  41  when the latter is in position. The fastenings  40  may therefore be juxtaposed on the rails  2  and  3  with a high density. 
     The base  41  also extends in two handles  416  and  417  outside the hooks  414  and  415  with respect to the orifice  413 . The hook  414  and the handle  416  are separated by a clearance slit  420  while the hook  415  and the handle  417  are separated by a similar slit  421 . The handles  416  and  417  each define a zone  416   a  or  417   a  for receiving a tool  60 , shown solely in dashed and dotted lines in FIG. 2, for exerting an effort F for unhooking hooks  414  and  415  engaged on the beaks  22   b  and  32   b.    
     In the embodiment shown in FIG. 2, the flexible nature of the hook  414  is used for allowing the hook  415  to be unhooked from the beak or hook  32   b . Of course, the tool  60  might be used on the handle  416  to allow unhooking in the opposite direction. 
     The fact that a handle  416  or  417  is provided on each side of the base  41  allows for unhooking the fastening  40 , including when the latter is accessible by one side and independently of its direction of assembly. 
     Handles  416  and  417  extend respectively in tongues  418  and  419  provided to penetrate in orifices  70   a  and  71  a of two guide bars  70  and  71  arranged respectively in the channels  23  and  33 , being slid in grooves  21   a  and  22   a ,  31   a  and  32   a , respectively. The pitch p of the orifices  70   a  and  71   a  on the bars  70  and  71  determines the pitch of installation of the bars  70  on the rails  2  and  3 . This pitch is chosen to be slightly greater than the thickness e of the fastenings  40 . 
     As shown in FIG. 1, when it is necessary to add a fastening  40  on the rails  2  and  3 , this fastening is arranged above the rails, being displaced in a direction substantially parallel to its principal plane, as represented by the arrow of displacement D, then applied in the direction of plates  6 , the rounded shape of the hooks  414  and  415  cooperating with the likewise rounded shape of the beaks  22   b  and  32   b  in order to allow automatic hooking by elastic deformation of these hooks. Each fastening  40  is thus arranged with its principal plane parallel to the direction Y-Y′. The adjustment in direction X-X′ is effected by relying on the pitch of the orifices  70   a  and  71   a.    
     Dismantling is effected with the aid of the tool  60  as indicated hereinabove, in particular when one of the rods is damaged. Dismantling can also be effected by hand, by exerting an effort of traction on one of the handles  416  or  417  or on another part of the base  41 . 
     In the second embodiment of the invention shown in FIG. 6, elements similar to those of the first embodiment bear identical references. The fastening  40  of this embodiment is intended to be mounted on a section of the type formed by the rails  2  and  3  shown in FIGS. 1,  2 ,  4  and  5 . This fastening differs from the preceding one in that the rods  42  are substantially shorter than those of the first embodiment and in that their ends  42   a  do not present any branches. 
     The hooks  414  and  415  are respectively formed at the end of two elements  41 ′ and  41 ″ extending from the base  41  opposite the edge  411 . The handles  416  and  417  for maneuvering the hooks  414  and  415  are also arranged on these elements  41 ′ and  41 ″, with the result that there is no slit separating these hooks and these handles as in the first embodiment. The bending movements of the elements  41 ′ and  41 ″ allow elastic hooking and unhooking of the hooks  414  and  415  on and from the corresponding beaks of the section. 
     Positioning tongues  418  and  419  are also provided in the lower part of elements  41 ′ and  41 ″ and are intended to cooperate with spacer bars of the type such as bars  70  and  71  described with reference to the first embodiment. These tongues  418  and  419  may present a thickness different from that of the rest of the elements  41 ′ and  41 ″. 
     A shed forming device equipped with an assembly as shown in FIG. 1 is easy to install on a weaving loom, being particularly reliable and its maintenance being greatly simplified with respect to the devices of the state of the art. A weaving loom equipped with such a device is therefore cheaper to install and maintain than the known looms. 
     The geometry of the beaks  414  and  415  and of the hooks  22   b  and  32   b  may be changed without departing from the scope of the present invention. In particular, the beaks of the base may be provided to be arranged between the hooks formed by the elongated section.