Abstract:
Equipment for stripping a multi-core cable, includes a transport unit for axial movement of the cable, knives for desheathing and stripping the insulation from the cores, and a separator for untwisting the cores and orienting them parallel for acting upon by the stripping knife in a manner that axial forces are not applied to the insulator of the cores. Greater control over and precision associated with the stripping process is obtained.

Description:
[0001]    The invention relates to equipment for stripping a multi-core cable, wherein a transport unit for transport of the cable in the axial direction of the cable, a knife for desheathing the cable and a further knife for stripping the untwisted cable cores are provided.  
         BACKGROUND OF THE INVENTION  
         [0002]    A stripping device for multi-core cables has become known from the disclosure of WO99/52188. Cable cores are mechanically untwisted by a stripping movement and oriented parallel to one another before the cable cores are stripped by means of multiple knives. The stripping movement and the parallel orientation are achieved by means of spring-loaded, mutually opposed jaws, wherein the jaws act as resilient slide members. The cable cores execute a movement relative to the slide members whereby the untwisted cable cores are separated and oriented to be parallel before the stripping.  
           [0003]    A disadvantage of the known equipment resides in the fact that, due to the stripping movement, forces act in the cable&#39;s axial direction on the insulation of the cable cores which slightly stretch the insulation. After the stripping, the insulation can compress again, resulting in overly-large, material-dependent stripped lengths.  
         BRIEF DESCRIPTION OF THE INVENTION  
         [0004]    The present invention avoids the disadvantages of known equipment and presents a construction by means of which the cable cores of a cable can be untwisted and oriented in problem-free manner.  
           [0005]    The advantages achieved by the invention are essentially to be seen in the fact that the resilient insulation is not stretched during untwisting of the cable cores. The stripped length of the cable cores does not change after the untwisting. The stripped length of the cable cores as predetermined by the stripping is maintained. Moreover, shorter desheathed lengths can be realised, because the insulation is not stretched.  
           [0006]    The invention includes a transport unit for axial transport of the cable, a knife for desheathing the cable, means for untwisting the cores and orienting the cores parallel to each other, and a knife for stripping the cores. The cores are untwisted and oriented parallel without the application of an axial force to their installation. The untwisting and orientation may be performed by a separator which may include rollers, engage the cores and act transversely to the axial direction of the cable. 
       
    
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0007]    The present invention is explained in more detail on the basis of the accompanying figures, in which:  
         [0008]    [0008]FIG. 1 is a perspective view of the invention;  
         [0009]    [0009]FIG. 2 is a view of a first portion of a desheathing step;  
         [0010]    [0010]FIG. 3 is a view of a second portion of a desheathing step;  
         [0011]    [0011]FIG. 4 is a perspective view of a separator of the invention in an open setting for the untwisting of the cable cores;  
         [0012]    [0012]FIG. 5 is a view of the separator in a closed setting;  
         [0013]    [0013]FIG. 6 is a view of the separator in a closed setting with a profiled knife;  
         [0014]    [0014]FIG. 7 is a detail view of the separator with the profiled knife in an open setting; and  
         [0015]    [0015]FIG. 8 is a sectional detail view of the separator. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0016]    [0016]FIG. 1 shows stripping equipment  1  of the invention for the stripping of a cable  2  with several cable cores  3 . The cable cores are typically twisted and sheathed by a cable sheath  4 . A main axial cable direction is denoted by  5 .  
         [0017]    The cable  2  can be advanced and drawn back through the equipment by means of a first transport unit  6 , wherein upper and lower drivable roller pairs  7  produce the movement of the cable  2 . The cable forward end or start  8  is advanced through a guide tube  10 , which is pivotable by means of a pivot mechanism  9 , to a separating knife  11 , wherein the separating knife  11  is provided for cutting through the cable  2  and for desheathing the cable  2 . A setscrew  11 . 1  enables a quick exchange of a knife block having the separating knife  11 . Arranged between the end of the guide tube  10  and the separating knife  11  is a first separator  12  for untwisting the cable cores  3 , and a first profiled knife  13  for stripping the cable cores  3 .  
         [0018]    For processing the opposed severed cable end  14 , the corresponding length of cable  2  can be advanced and drawn back by means of a second transport unit  15 , wherein upper and lower drivable roller pairs  16  produce the movement of the cable  2 . Arranged between the transport unit  15  and the separating knife  11  is a second separator  17  for untwisting the cable cores  3  and a second profiled knife  18  for stripping the cable cores  3 . The separating knife  11  and the profiled knives  13 ,  18  each comprise a pair of upper and lower knives.  
         [0019]    The transport units  6  and  15 , the pivot mechanism  9 , the knives  11 ,  13 ,  18  and the separators  12  and  17  are arranged at a mount  19 .  
         [0020]    [0020]FIG. 2 shows the forward end  8  of the cable  8  after severing of the cable by the separating knife  11 . The opposed severed cable end  14  is not illustrated. For the desheathing, the cable  2  is advanced the desired desheathing length “a” by means of the first transport unit  6 . Thereafter, the separating knife  11 , consisting of two halves, is advanced so that the cable sheathing  4  is cut into. The first transport unit  6  then draws the cable  2  back, wherein, as shown in FIG. 3, a sheath residue  20  is pushed off by the separating knife. The cable cores  3  are now free, but still twisted. The processing of the opposed cable end  14  takes place analogously to the processing of the cable end  8 .  
         [0021]    [0021]FIG. 4 shows the first separator  12  (without first profiled knife  13 ) in the open setting. The separator  12  consists of a lower, freely rotatable roller  12 . 1 , which is supported by a lower roller mount  12 . 2 , and an upper, freely rotatable roller  12 . 3 , which is supported by an upper roller mount  12 . 4 . The roller mounts  12 . 2 ,  12 , 4  are driven in a spring-loaded manner in the vertical direction.  
         [0022]    [0022]FIG. 5 shows the first separator  12  in the closed setting. The roller mounts  12 . 2 ,  12 , 4  are driven in the vertical direction towards each other and against the cable. Upon the advance of the first separator  12  the cable  2  is so positioned in the cable&#39;s axial direction that the cable core  3  near to the cable sheath end lies between the lower roller  12 . 1  and the upper roller  12 . 3 , at which time the lower roller  12 . 1  executes a movement QU transversely to the cable axis  5 , for example away from the mount  19 , while the upper roller  12 . 3  simultaneously executes a movement QO oppositely transverse to the cable axis  5 , for example in the direction of the mount  19 . After the transverse movements QU, QO of the rollers  12 . 1 ,  12 . 3 , the separator  12  is opened and the cable  2  drawn back, for example by a third of the free cable core length, and the transverse movements QU, QO are applied again to the cable cores  3 . The preceding step can be repeated as required by the respective twisting, in that the separator  12  is opened and the cable is drawn back by a further third and the transverse movements QU, QO are applied again to the cable cores  3 . Strongly twisted cable cores can be untwisted by further stepwise application of the transverse movements QU, QO or forces to the cable cores  3 . In the case of weaker twisting, a single application of the transverse movements QU, QO may be sufficient for the untwisting and parallel orientation of the cable cores  3 . The untwisting can also be carried out, without cable transport, merely by multiple dosing and opening of the separator  12 .  
         [0023]    After untwisting, the cable may be axially repositioned in the separator as required to allow the desired length of the cable cores to be stripped. FIG. 5 and FIG. 7 show the parallel orienting of the cable cores  3 . Due to the freely rotatable rollers  12 . 1 ,  12 . 3 , virtually no forces act in the cable axial direction on the insulation of the cable cores  3  during subsequent stripping of the cable cores  3 . After the stripping of the cable cores  3 , the stripped length is maintained.  
         [0024]    [0024]FIG. 6 shows the separator  12  in the closed setting with the profiled knife  13  cutting into the core insulation. The profiled knife  13  comprises a lower knife  13 . 1  and an upper knife  13 . 2 , wherein the knives  13 . 1 ,  13 . 2  have a number of cutting profiles  13 . 3 , which correspond to the number of cable cores  3 . Opposed limbs  13 . 4  arranged laterally of the cutting profiles  13 . 3  limit the transverse movement of the cable cores  3  during the untwisting before the profiled knife is activated. After cutting into the core insulation the cable  2  is drawn back by means of the first transport unit  6  and, as shown in FIG. 7, the separator  12  together with the profiled knife  13  is opened. The predetermined stripped length is denoted by b and the insulation residues are denoted by  21 .  
         [0025]    The separators  12 ,  17  can be driven with the associated profiled knife  13 ,  18  or can have their own drive.  
         [0026]    The untwisting, the orienting to be parallel and the stripping of the cable cores  3  of the cable end  14  is carried out analogously to the processing of the cable end  8 .  
         [0027]    [0027]FIG. 8 shows details of the upper roller mount  12 . 4  of the separator  12 . The roller mount  12 . 4  consists of a roller support  12 . 41  supporting the upper roller  12 . 3  and a slide member  12 . 42 , which slide member  12 . 42  is displaceably arranged in a housing  22 . The slide member  12 . 42  is loaded by means of a spring force emanating from compression springs  23 . A pin  24  of the slide member  12 . 42  engages in an elongate slot  25  of the housing  22 , wherein the pin  22  and thus the roller mount  12 . 4  and roller  12 . 3  is limited in terms of travel by the ends of the elongate slot  25 .  
         [0028]    In FIG. 8 the roller mount  12 . 4  is shown driven out in the vertical direction by a solid line and driven inwardly in the vertical direction, by a dashed line. The maximum possible stroke of the roller  12 . 3  is denoted by VO. Due to the inclined arrangement of the slide member  12 . 42 , the roller  12 . 3  also executes a movement in the horizontal direction. The maximum possible movement in the horizontal direction is denoted by HO. As explained further above, the movement in the horizontal direction serves for untwisting the cable cores  3 .  
         [0029]    The function and mode of construction of the lower roller mount  12 . 2  are analogous to that of the upper roller mount  12 . 4 .