Patent Publication Number: US-11028513-B2

Title: Loop gripper handling device and handling unit and process for handling loop gripper modules

Description:
RELATED APPLICATION(S) 
     This application claims the benefit of European Patent Application No. 18162083.2, filed Mar. 15, 2018, the contents of which are incorporated herein by reference as if fully rewritten herein. 
     TECHNICAL FIELD 
     The invention relates to a loop gripper handling device, a handling unit, and a process for handling loop gripper modules, especially cut pile loop gripper modules. 
     BACKGROUND 
     The principle of loop gripper modules is known from the prior art. For example, EP 1 826 307 A1 describes a loop gripper module that has a number of flat gripper fingers that are oriented parallel to one another and that are held in a base body. Every gripper finger is associated with a slider that is movably held on the loop gripper module, in order to control the loop formation process by being made to undergo controlled translational motion relative to the loop gripper module. Every gripper finger is associated with a slider. 
     As the module is mounted on the tufting machine, the sliders must be connected with a drive element, so that the sliders can be individually moved alone or also moved synchronously on the loop gripper module. 
     Therefore, as a loop gripper module is mounted on the tufting machine, all sliders must be moved into a uniform coupling position, so that they can be connected with the drive elements with which they are associated. 
     WO 2006/076558 A1 also discloses a loop gripper module with sliders that are associated with the gripper fingers and that are held so that they are longitudinally movable on the loop gripper module. Here again, the above-mentioned problem arises in the same way. 
     DE 29 46 092 A1 describes a two-part loop gripper module. It comprises a first base body that holds gripper fingers that are arranged parallel to one another, and a second base body that holds the same number of bails that are oriented parallel to the gripper fingers and that are associated with them. Axial relative motion between the gripper fingers and the bails is not provided. 
     U.S. Pat. No. 2,944,662 A discloses a packaging for plate-like elements, such as, especially printed circuit boards. The packaging comprises a box with a block arranged in it that has slots in which the flat parts are held by friction. The block can consist of wax or gelatin or also of another material. 
     DE 102 44 315 B4 further discloses a tool carrier for slide needles and a shipping unit formed from it. The tool carrier is formed by a two-legged, thin-walled profile, whose free legs are slotted. The slots hold the slide needles. A cover closes the rail, to prevent loss of the needles from the carrier rail. 
     It is one goal of the invention to indicate a concept that can simplify the mounting of tufting modules on a tufting machine. 
     SUMMARY 
     This is accomplished with a loop gripper handling device, a handling unit, and a process for handling loop gripper modules as disclosed and described herein. 
     The inventive loop gripper handling device is suitable especially for handling cut pile loop gripper modules or other tufting modules, which have a number of longitudinally movable sliders. The loop gripper handling device is a clamping device with a number of clamping receptacles arranged in a row. These clamping receptacles are associated with the sliders of the loop gripper module, and can be connected with the loop gripper module. This holds the sliders in their respective axial positions, so that during transport and also during insertion into a tufting machine their axial position relative to the loop gripper module does not change. This makes it especially simple to couple the entire group of all sliders with the drive device as a tufting module is attached to the tufting machine. If the sliders have a coupling recess at their machine-side end, all coupling recesses are in the correct coupling position in which the machine-side coupling part is also located. Thus, the handling of the tufting modules during mounting requires substantially less dexterity than up to now, and can be carried out more quickly and more securely. 
     Preferably, the clamping device is designed so that the sliders are held in the individual clamping receptacles by friction, so that they cannot be moved in the axial direction. The frictional force acting between the sliders and the corresponding surfaces of the clamping receptacle that lie opposite one another in the clamping receptacles is preferably greater than any accelerating force acting on the sliders that occurs during transport of the loop grippers. This ensures that the sliders do not change their position during transport. 
     Preferably, the clamping receptacles are slot-like grooves, both of whose facing surfaces are planar or also convex surfaces, which are arranged and shaped to be mirror symmetric to one another about an imaginary midplane of the slot. The surfaces of the clamping receptacle are preferably continuous, forming a large surface area between the respective slider and the surface of the clamping receptacle lying against it. This achieves high static friction, and secures the position of the sliders very well. On the other hand, the surfaces of the clamping receptacles do not predetermine any preferred position of the clamping device with respect to an axis of rotation of the clamping device that is directed transverse to the directions of motion of the sliders. The result is that the clamping device can hold all sliders with substantial clamping force and can nevertheless be put on the sliders, and removed from it by hand. Putting the clamping device on and removing it is substantially facilitated by the possibility of rotating the clamping device about the mentioned axis that is oriented transverse to the sliders. 
     The clamping device preferably has a number of clamping receptacles whose number coincides with the number of sliders of a loop gripper module. The clamping receptacles are, like the sliders, preferably arranged at uniform distances from one another. 
     The clamping device is preferably formed by a beam-like body that has a series of slots formed in it that form the clamping receptacles. The body is, for example, a rectangular cuboid. The body preferably consists of a plastic, preferably a plastic that has an inherent pliability that is at least large enough that the clamping forces acting between every slider and its clamping receptacle can be overcome by hand. 
     The clamping receptacles preferably have, at their open side lying opposite the bottom, a widening forming an insertion bevel which facilitates putting a clamping device onto the sliders of a loop gripper module. 
     The individual sliders are preferably seated in the clamping receptacles of the clamping device solidly enough that with the clamping device it is possible to pull all sliders out of the gripper module by a linear motion in the longitudinal direction of the sliders. This allows the sliders to be kept ready in the clamping device, for example for regrinding or for cleaning work, and also to be inserted back into the loop gripper module as a group. 
     According to the invention the loop gripper module and the clamping device form a handling unit, which allows all sliders to be moved together in the axial direction. The clamping device holds all sliders in an identical axial position, so that they cannot move with respect to one another even during transport. This clamping is solid enough that the axial position of the sliders with respect to one another does not change even if the loop gripper module undergoes a shaking movement. 
     The invention has special advantages for mounting the loop gripper module on a tufting machine. The loop gripper module is set into a swiveling motion on the bar of the tufting machine, during which all coupling ends of the sliders simultaneously engage with the corresponding coupling of the drive part of the tufting machine. After the loop gripper is mounted, the clamping device is removed, so that the sliders can now move freely, controlled by the drive device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further details of advantageous embodiments of the invention are the subject of the description, the drawing, or the subordinate claims. The figures are as follows: 
         FIG. 1  is a perspective schematic diagram showing a handling unit consisting of a loop gripper module and a clamping device; 
         FIG. 2  is a perspective schematic diagram showing the clamping device of the handling unit according to  FIG. 1 ; 
         FIG. 3  is a sectional view of a first embodiment of the clamping device according to  FIG. 2 ; 
         FIG. 4  is a partial sectional view of a modified embodiment of the clamping device according to  FIG. 2 ; and 
         FIG. 5  is a schematic diagram showing the handling unit as it is mounted on a tufting machine. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a handling unit  10 , including a loop gripper module  11  and a clamping device  12 . The loop gripper module  11  corresponds to a conventional design, such as is disclosed, for example, from WO 2006/076558 A1 or EP 1 826 307 A1. The loop gripper has gripper fingers  13  through  22 , which are held in a base body  23  and extend away from the base body  23  parallel to one another at equal lateral distances from one another. The gripper fingers  13  through  22  are secured in the base body  23  so that they are axially fixed. 
     Every gripper finger  13  through  22  is associated with a slider  24  through  36 . The sliders  24  through  33  are supported in the base body  23  so that they are axially movable. To accomplish this, the sliders  24  through  33  are seated in corresponding channels, which are formed in the gripper fingers  13  through  22 . The rear coupling sections  24   a  of the sliders  24  through  33  project out of their respective guide channels. The sliders  24  through  33  are straight, flat sheet metal parts, which are held in the predefined axial position by the clamping device  12 . 
     The clamping device  12  is a preferably single-piece, for example cuboid-shaped body made of plastic or another, somewhat pliable material, as is illustrated in  FIG. 2 . The body  12  has clamping receptacles  37  through  43  formed in it, which are preferably formed by slot-like, straight grooves that are parallel to one another.  FIG. 3  illustrates the groove  37  as an example of all grooves  37  through  46 , which are arranged at equal distances. The distances between the grooves  37  through  46  correspond to the distances between the sliders  24  through  33 .  FIG. 3  illustrates a clamping receptacle  34  as a representative of the rest of the clamping receptacles  34  through  43 . It is formed by a slot delimited by two preferably planar walls  35 ,  36 . The two walls  35 ,  36  are arranged symmetrically with respect to a midplane  37 . If the wall surfaces  35 ,  36  bulge, they are also arranged symmetrically with respect to the midplane  37 . 
       FIG. 4  illustrates a modified clamping receptacle  34 , in which the wall surfaces  35 ,  36  have sloping surfaces  39 ,  40  at the place farthest away from the slot floor  38 , these sloping surfaces  39 ,  40  forming a wedge-like widening of the clamping receptacle  34  and serving as insertion bevels for the respective slider associated with each of them. 
     The wall sections of the preferably solid base body of the clamping device  12 , which lie between the individual clamping receptacles  34  through  43 , can have a certain small pliability, so that every slider  24  through  33  sits clamped, i.e., held in a frictionally engaged manner, in the respective clamping receptacles  34  through  43 . The oversize of the slider with respect to the clamping receptacle is preferably dimensioned so that manual force is sufficient to put the clamping device  12  onto the sliders  24  through  33  and to remove the clamping device  12 . 
     Assembly with the tufting machine is done as indicated in  FIG. 5 . For illustration, this figure shows a bar  41  that is fitted with a series of loop gripper modules  11  and that executes an oscillating movement to grip and hold, and possibly cut loops. The bar is associated with one or more drives  42 , which carry a coupling structure  43  at their respective module-side end. This coupling structure  43  is set up to engage in a form-fit manner with the coupling end  24   a  of the respective slider  24 . The coupling structure  43  and the coupling end  24   a  are complementary to one another, and fit into one another form-fit manner. They can be engaged and disengaged by a coupling movement. The coupling movement typically differs from the longitudinal movement of the sliders  24 - 33 . 
     To mount the loop gripper module  11 , the handling unit  10  is, as illustrated in  FIG. 5 , put onto the bar  41 , which requires that a positioning projection  44  engage into a corresponding recess  45  of the bar  41 . The handling unit  10  is set on the bar  41  as indicated in  FIG. 5  by arrows  46 ,  47 ,  48 , with a slight swiveling movement, which involves the positioning projection  44  or any other positioning structure going into the associated recess  45  and the coupling end  24   a  going into the coupling structure  43 . 
     After the loop gripper module  11  is fastened to the bar  41 , the clamping device  12  can be removed. The machine is then operational. 
     For service purposes, the loop gripper modules  11  can be removed from the bar  41 . Before the loop gripper modules  11  are detached from the bar  41 , first a clamping device  12  is pushed onto all sliders  24  through  33  of every loop gripper module  11 . After that, the loop gripper module  11  is detached from the bar  41  and removed. Now, the sliders  24  through  33  cannot be axially moved relative to one another. However, they can be pulled off as a whole, i.e., all at once from the base body  23  to undergo, for example, cleaning or other processing. 
     The inventive handling unit  10  comprises a loop gripper module  11  and a clamping device  12 , which has a frictionally engaged connection with the sliders  24 - 33  of the loop gripper module  11 , however preferably not with the gripper fingers  13 - 22 . The sliders  24 - 33  are lightly clamped in corresponding slots of the clamping device and cannot, even if shaken, slip against one another and in particular they also cannot slide out of the loop gripper module  11 . Thus, the sliders  24 - 33  are all at the same axial position, and need not be moved back by hand during mounting. For example, in order to remove clamping device  12 , which is in the form of a plastic clip, the clamping device  12  need only be pressed onto the loop gripper module  11  or be pulled away from the loop gripper module  11 , both movements possibly combined with rotation about an axis of rotation in the direction transverse to the direction of motion of the sliders  24 - 33 . When this force is applied, the plastic clip can be lifted from the sliders  24 - 33  in a rotating movement. 
     REFERENCE NUMBERS 
     
         
           10  Handling unit 
           11  Loop gripper module 
           12  Clamping device 
           13 - 22  Gripper fingers 
           23  Base body 
           24 - 33  Sliders 
           34 - 43  Clamping receptacles 
           35 ,  36  Wall surfaces of clamping receptacle  34   
           37  Midplane of the clamping receptacle 
           38  Floor of slit 
           39 ,  40  Beveled edges serving as insertion bevels 
           41  Bar 
           42  Drives 
           43  Coupling structure 
           24   a  Coupling end 
           44  Positioning pin 
           45  Recess