Abstract:
A device for coupling heddle frames to rod or cable transmission elements of a mechanism for forming the shed in a weaving loom wherein a female mortise member includes a slot having a pair of opposing arms on either side thereof which shot is traversed by the transmission elements which transmission elements pass through a male tenon member which is adjustably fixed thereto with the aid of a locking mechanism and which male tenon member interengages the female mortise member.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to dobbies and other mechanisms for forming the shed in weaving looms, and more particularly to the coupling of the heddle frames on the cables or other transmission elements intended for maneuvering them. 
     2. History of the Related Art 
     It is know that, in mechanisms associated with a drawing system of the negative type one of the ends of each of the maneuvering cables is generally secured to one of the swinging drawing levers of the mechanism while the opposite end is connected, through a pivoting sector to a set of springs adapted to return the corresponding heddle frame to the rest position after it has been positively displaced by mechanism. Between its two points of fixation, the cable is guided by a lower detour pulley, presents a segment oriented substantially vertically, which follows along the upright of the frame. 
     In certain cases, each heddle frame is suspended from its two lateral pivoting sectors by means of articulated rods, but in other applications, it is the upright of the frame which is fixed to the vertical segment of the cable, without any articulation, in the manner illustrated in FIG. 1. The present invention refers to this latter mode of assembly. 
     Experience has shown that the operations of assembly and dismantling of the heddle frames are difficult. The uprights of each frame are generally fixed to the cables by mechanisms incorporating collars or screwed flanges which are difficult to manoeuvre. Assembly systems have been proposed which employ male and female members in the form of tenon and mortise, but the structural solutions adopted still remain relatively complex to carry out and their reliability is mediocre. 
     SUMMARY OF THE INVENTION 
     It is a principle object of the present invention to overcome the aforementioned drawbacks, by providing, in an assembly incorporating members in the form of tenon and mortise which are secured, some with the cable, the others with the uprights of the frame in order to be opposite along the same substantially vertical plane. The members which are slit parallel to the plane of the frame form, on either side of the cable, contact surfaces between the tenons and the mortises for transmission of efforts or forces. 
     It will be readily appreciated that such a structure avoids non-alignment of the lines of force and the surfaces of application of these forces in the coupling system, with the result that the two combined tenon and mortise members do not require any reciprocal fixation. The fit with reduced clearance between the tenon and mortise members is sufficient to alone ensure the transmission of the drawing efforts or forces developed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be more readily understood on reading the following description with reference to the accompanying drawings, in which: 
     As indicated in the preamble, FIG. 1 is a view in elevation schematically illustrating the arrangement of the invention associated with a drawing system of the negative type. 
     FIG. 2 is a vertical section through a coupling device according to the invention. 
     FIG. 3 is a horizontal section of the coupling device of FIG. 2. 
     FIG. 4 shows in perspective, prior to assembly thereof, the different elements of the device of FIGS. 2 and 3. 
     FIG. 5 is a transverse section showing the conditions of transmission of the efforts or forces between the two members of the device. 
     FIGS. 6 and 7 are sections identical to those of FIG. 2 and FIG. 3 respectively, the member in the form of tenon having been shown after withdrawal from the member in the form of mortise. 
     FIGS. 8 and 9 show two variant embodiments of the invention. 
     FIG. 10 schematically illustrates the application of the invention to a drawing system of the positive type. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring again to the drawings, in FIGS. 1 to 5, one of the cables a is secured at one end around a pulley g to a swinging drawing lever b of operating mechanism c and at the other end to a vertical rod or motion transmission element 7. The other cable a&#39; is secured at one end to a member d which is pivotally mounted to frame member 15 and is acted on by a set of springs e and is joined at the other end to the vertical rod 7. The springs e act through the cable a&#39; and rod 7 to return the heddle frame f to a rest position after the frame has been positively displaced by operation of the operating mechanism c. Reference 1 designates one of the two uprights of heddle frame. Against this upright 1 has been added a fork element 2 of which the opening 2a is oriented horizontally towards the outside of the frame. This opening 2a defines two superposed arms, each of these arms having a vertical slot 2b cut out therein, of which the bottom is semi-cylindrical in cross-section. 
     It will be understood that this fork element 2 constitutes a female member in the form of mortise, adapted to receive in its opening 2a a tenon formed by the end 3a of a male member 3, having a vertical housing 3b open at its two ends and being hollowed out therein. In this housing 3b are mounted a jaw 4 and two pusher elements 5 connected to each other by a locking screw 6. As shown more clearly in FIG. 4, the jaw 4 presents, opposite a vertical bearing face 4a of semi-cylindrical section, two opposite oblique faces 4b which are adapted to cooperate with a ramp 5a provided on the side of each pusher element 5. 
     One of the pusher elements 5 has a vertical bore 5b hollowed therein, traversed by the screw 6 which cooperates with a similar vertical tapping 5b in the second pusher element, with the result that, by manoeuvring the screw 6, the pusher elements are brought closer together and they tend to drive the jaw 4 horizontally inside the housing 3b. 
     This housing 3b is traversed by a vertical rod or motion transmission element 7 which, in manner known per se in the systems of the negative type for drawing the heddle frames, interrupts at the level of the coupling device the cable secured to one of the levers of the dobby or other like mechanism, the ends of the rod 7 being crimped on the two ends of the cable envisaged. It will be appreciated that, if this rod 7 is inserted between the bottom of the housing 3b and the bearing face 4a of the jaw 4, the manoeuvre of the screw 6 ensures axial and lateral blockage of the rod against the tenon-shaped member 3, while allowing precise adjustment of this member with respect to the opening of the fork element 2. 
     It will be observed that the radius of the bottom of the two slots 2b of the fork element, the radius of the bottom of the housing 3b which faces the direction of the end 3a of the male member 3, and the radius of the bearing face 4a of the jaw 4 are substantially equal, to within a very slight clearance, to the radius of rod 7, as is clearly apparent in FIGS. 2 and 3. Furthermore, the horizontal edges of the opening 2a of the fork element 2 are oriented in strictly parallel manner and their spaced apart relationship is equal, to within a very slight clearance, to the height of the end 3a of the male member 3. 
     Under these conditions, the end 3a engages closely inside the opening 2a, virtually without clearance. The rod 7 is perfectly applied in the bottom of the slots 2b that it traverses vertically, so that a precise and stable fit is obtained, in which the effort or force transmitted passes substantially through the centre of the surfaces in contact, which contact surfaces, shown in FIG. 5 by hachuring, are disposed on either side of the axis of rod 7. Consequently, any creation of rocking moment is avoided, so that a mutual fixation of the members 2 and 3 with the aid of screws or other separate pieces can be dispensed with, whatever the amount of the effort to be developed for the vertical manoeuvre of the heddle frame shown. 
     With a view to avoiding any lateral displacement of the male member 3 in the course of operation of the weaving loom, this member is provided, opposite end 3a, with a heel 3c of which the tail is engaged with reduced clearance inside the opening 8a of a vertical U-sectioned slide 8 permanently fixed against the structure of the loom 15 on each of the sides of the heddle frames thereof. This slide 8 is positioned so as not to hinder assembly and dismantling of the heddle frames on the rods 7, these operations being effected by outwardly displacing the cables which support the rods, in the manner illustrated in FIGS. 6 and 7. These operations are, of course, simplified as they require no manoeuvre of screws or other securing member at each coupling device. 
     The device according to the invention makes it possible considerably to reduce the overhang existing between each of the uprights 1 of the heddle frame and the axis of the cable which ensures displacement thereof. This overhang may further be reduced to its minimum value by adopting the variant embodiment illustrated in FIG. 8, in which each upright 1 is constituted by a C-sectioned piece against the web or bottom of which is fixed the fork element 2, so that the rod 7 itself is housed inside the C-shaped piece or upright. 
     In addition, it will be understood (cf. FIG. 9) that the above described arranged may be reversed by fixing the fork element 2, equipped with a heel 2c introduced in the slide 8 and with a jaw mechanism 4-5-6, against the rod 7 in order to cooperate with a male member 3 secured with the upright 1 of the heddle frame. It goes without saying that, in such a case, the jaw 4 presents the form of a stirrup to allow the male member 3 to penetrate into the opening 2a, which member is itself slit vertically to embrace the rod 7, as illustrated in FIG. 9. 
     It must, moreover, be understood that the foregoing description has been given only by way of example and that it in no way limits the domain of the invention which would not be exceeded by replacing the details of execution described by any other equivalents. In particular, in certain cases, it is possible to dispense with the rod 7, the jaw mechanism 4-5-6 ensuring direct fixation of the female member 2 or the male member 3 against the drawing cable or other motion transmission element which ensures manoeuvre of the heddle frame in question. 
     It should also be observed that the invention is applicable to drawing systems of the positive type in which the frames are controlled positively in both directions. As illustrated in FIG. 10, each transmission element is here formed, no longer by a cable, but by a rod 9 of polygonal section whose lower end is coupled by a rod 10 to a lever 11 which is itself connected by a rod 12 to the other lever 11 and by a rod 13 to the corresponding swinging drawing lever of the mechanism . Each rod 9 is therefore comparable to rod 7 of the preceding embodiments; its correct angular orientation is ensured by a vertical guide 14 which is fixed to the structure 15 of the loom by a mechanism which allows recoil of the guide 14 and the rod 9 with a view to the operations of assembly and disconnection of the male and female members of the coupling device associated with each upright 1 of the frame shown.