Abstract:
The invention relates to an insulation stripping device comprising an essentially tubular cable guide whose inside diameter can be continuously adjusted thereby enabling it to be adapted to different cable diameters.

Description:
[0001]     This application is a national stage completion of PCT/IB03/01954 filed May 22, 2003 which claims priority from Swiss Application Ser. No. 2002 0868/02 filed May 23, 2002. 
     
    
     BACKGROUND  
       [0002]     The invention relates to a cable guide for cable insulation stripping machines.  
         [0003]     Cable insulation stripping machines are frequently designed as continuously operating machines processing continuous cables and provide—before, after and between drive means and cable processing devices—guides for the cable to be processed. These guides are generally formed by tubes which have partly funnel-shaped infeed regions.  
         [0004]     In many cases, these tubes are pivotable (longer guide tube in PS 9500 Powerstrip) or displaceable (shorter guide tubes in PS 9500 Powerstrip) or are fixed, so that cable sections can optionally be fed to a processing device or in a direction pointing away from the processing device, or that the guides are removable from their operating position, or that guides are always arranged in the same place.  
         [0005]     Conventional cable guides are formed in each case for specific cable diameters and accordingly have to be changed manually.  
         [0006]     However, this manual changing requires a relatively long time and some manual skill, so that it is an object of the invention to reduce the effort involved in manipulating the known cable guides.  
         [0007]     The use of a revolver head having a plurality of tubes of different internal diameters fastened therein, which can be brought as required into their operating position by turning the revolver head, is proposed as an obvious solution to this problem. Such a solution is also provided in the PS 9500 Powerstrip of the Applicant before a first transport means.  
         [0008]     Such a revolver head having cable guides has also become known in the case of insulation stripping machines MP 8015 of the Applicant. However, the cable guide used there is not employed for continuous cable processing but for an insulation stripping device by means of which in each case insulation can be stripped only from end regions of individual cable sections.  
         [0009]     This previous solution has the following disadvantage compared with the original solution with changeable guide tubes: since the axis of rotation of the revolver has to be located outside the centre of the cable, the lateral construction size increases. During the rotation operation of the revolver, the cable has to be removed from the guide and at the same time no cable feed can take place. In the event that incorrect guide tubes are selected in error, the original solution as well as the revolver head solution is inconvenient in that the cable has to be completely unthreaded again before the guide can be changed. This is disadvantageous and time-consuming for the user.  
         [0010]     Moreover, the known solutions can be used only in association with existing, stepped guide tube diameters, so that cable diameters which are between the steps of the individual guide tubes can be guided only with greater difficulty than cable diameters which exactly fit the step present.  
         [0011]     The prior art also discloses further superstructures having adjustable guides:  
         [0012]     U.S. Pat. No. 4,489,490 describes a manual device for cable slitting and insulation stripping, in which a prismatic support which centres the cable is provided. A back-stop which is adjustable in height and presses the cable against the prismatic support and thus centres it laterally in one direction is present opposite the prismatic support. In this design, concentric guidance is not possible since the cable lies at a greater or lesser depth in the prismatic support depending on the cable diameter.  
         [0013]     U.S. Pat. No. 4,181,047 describes a cable insulation stripping device having a total of four guide rollers which are arranged in pairs one behind the other and, viewed in cross-section, form a rectangular guide channel (cf.  FIG. 3 ), which, however, is open in each case on two sides and cannot therefore perform complete guidance and support of the cable on all sides.  
         [0014]     U.S. Pat. No. 5,979,286 describes a two-sided guide in which two elongated guide bars can be displaced relative to one another by means of threaded spindles. This design, too, therefore does not permit guidance on all sides and also does not provide continuous centring of the cable since the centre of the cable is displaced upwards or downwards depending on the cable diameter.  
         [0015]     U.S. Pat. No. 5,820,008 shows, in  FIGS. 7 and 8 , a guide which—controlled by means of a cone—permits the displacement of two jaws having guide surfaces ( 228  and  248 ). It is true that this permits closing of the jaws onto a small cable diameter; however, the centre of the cable is likewise displaced depending on the cable diameter. Moreover, this design, like that described directly above, lacks true concentric guidance since there are no symmetrical support surfaces for a cable.  
       SUMMARY  
       [0016]     It is therefore an object of the invention to facilitate the manipulation with guides in association with a change of cable diameter. A second object, to be achieved simultaneously, is to permit continuous adaptation to different cable diameters.  
         [0017]     It is intended thereby to eliminate the disadvantages which arise in the case of the original solution and in the case of the solution involving the revolver head.  
         [0018]     The two objects are achieved by providing a system having at least one tube whose internal diameter can be changed by changing the tube geometry at least approximately symmetrically relative to the longitudinal axis of the tube.  
         [0019]     Such a change of geometries can be effected, for example, by a segment-like design whose segments can be adjusted relative to one another so that the internal tube diameter changes continuously. It can also be effected if the tube wall is made flexible and can be stretched or compressed. Thus, the tube may be designed, for example, as a spring which is spiral in cross-section and can be adjusted in its internal diameter by the action of a force from outside.  
         [0020]     A specific embodiment of the invention envisages that the segments are formed from elongated, rigid plates which are guided relative to one another, similarly to an iris diaphragm in a camera or similarly to the centring jaws in the rotary box of the Scheulinger model PS 9500 Powerstrip machine, or in models MP 8015 or JS 8300. The centring jaws of the rotary box and those of the JS 8300 are stationary, whereas the centring jaws of model MP 8015 rotate with the knives.  
         [0021]     In contrast to these known centring means or clamping devices, elongated plates are several times longer than the maximum adjustable diameter of the guide tube.  
         [0022]     Another specific embodiment uses an elongated spiral spring or a spiral spring body which is composed of spiral spring segments and can be operated with diameter variation so that the inner end or ends of the spiral spring or of the spiral spring segments rests or rest against the inner wall of the spiral spring or against the inner wall of an adjacent spiral spring segment, or slide along this during the adjustment. Suitable material for the spiral spring (segments) are conventional spring metals, for example spring steels, or plastics, in particular fibre-reinforced plastics.  
         [0023]     Both specific embodiments described can also be combined with one another by connecting spiral spring segments to the rigid segment plates so that the segment plates provide a seal against one another.  
         [0024]     The advantage of the segment plate solution is a robust, rigid design, while the advantage of the spiral spring or spiral spring segment construction entails less mechanical complexity.  
         [0025]     A seal between tube segments sliding against one another may be advantageous for certain cable types (in particular for fine wires), in order to prevent jamming of such wires.  
         [0026]     In a further development of the invention, the adjustment is effected by means of a motor—in particular with electronic actuation—so that an operator or a sensor-controlled controller sets the internal tube diameter required in each case. Embodiments in which the cable information—either detected by sensors or input by programming—automatically sets the correct diameter via the machine control are particularly advantageous.  
         [0027]     These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings, where: 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0028]      FIG. 1  shows a version of a universal guide in exploded view.  
         [0029]      FIG. 1   a  further shows the universal guide of  FIG. 1  in the assembled state.  
         [0030]      FIG. 2  shows another version of the universal guide in exploded view.  
         [0031]      FIG. 2   a  further shows the universal guide of  FIG. 2  in the assembled state.  
         [0032]      FIG. 3  shows yet another version of the universal guide in exploded view.  
         [0033]      FIG. 3   a  further shows the universal guide of  FIG. 3  in the assembled state.  
         [0034]      FIG. 4  shows a short guide segment.  
         [0035]      FIG. 5  shows a long guide segment.  
         [0036]      FIG. 6  shows another version of the adjustable guide.  
         [0037]      FIG. 7  shows a further version of the adjustable guide.  
         [0038]      FIG. 8  illustrates another version of the adjustable guide.  
         [0039]      FIG. 9  shows a further version of the adjustable guide.  
         [0040]      FIG. 10  is a perspective view of another version of the adjustable guide.  
         [0041]      FIG. 11  further shows the adjustable guide of  FIG. 10  in an exploded view. 
     
    
     DETAILED DESCRIPTION  
       [0042]     The description of the figures and the list of reference numerals form a unit which supplement one another through the other parts of the description and claims in the context of a complete disclosure.  
         [0043]     Identical reference numerals denote identical components; reference numerals having identical numbers but different indices denote different components having the same function or tasks. The figures are described as a whole and in association with one another and are shown only by way of example and not necessarily in correct proportions.  
         [0044]     Since they only represent embodiments, the description of the figures does not limit the invention.  
         [0045]     The invention is described in more detail by way of example with reference to diagrams.  
         [0046]      FIG. 1  shows the design of a universal guide in an exploded view, in which, starting from a cover  3 , a multi-part guide segment body  4 , which is held by a guide holder  1 , is shown. It is evident here that opening or closing of guide segments  17  is effected by means of guide slots  18  in the cover  3  via the straight pins  12  and  13  acting as bearing elements as shown. The guide segments  17  are connected to the respective coordinated parts of the guide segment body  4 , and are optionally formed integrally therewith. Per partial guide segment body  4 , straight pins  12 ,  13  are likewise firmly connected to it. The parts of the guide segment body  4  provide mutual support or slide past one another during adjustment.  
         [0047]     Socket-head cap screws  11  clamp the cover  3  to the guide holder  1  and a scale-bearing cover  5  which is connected to a casing  19 . The casing  19  and/or the cover  3  or the guide segments  17  can be provided at their end, for example, with a funnel-shaped conical infeed region.  
         [0048]     A cam plate  2  on which the scale-bearing cover  5  is held by means of a nut, for example a knurled nut  7 , so as to be axially displaceable rests on a sliding bearing  6  on the guide holder  1 . The scale-bearing cover  5  has the task of making it possible for a user to set a chosen tube diameter setting. Spring-loaded thrust pieces  8  which are secured by hexagon nuts  14  lock the scale-bearing cover  5  relative to the cam plate  2 .  
         [0049]      FIG. 1   a  shows the universal guide according to the invention, as shown in  FIG. 1 , in the assembled state.  
         [0050]      FIG. 2  shows an embodiment of a universal guide which is distinguished by particularly short guide segments  17   a.  Depending on requirements, it is fixed rigidly in position or is mounted before and after the knife head (in PS 9500 Powerstrip) so as to be vertically displaceable, analogously to the known vertically displaceable guides, which is not shown. However, it has no casing  19 , as shown in  FIG. 1 .  
         [0051]      FIG. 2   a  shows the embodiment according to  FIG. 2  in the assembled state.  
         [0052]      FIG. 3  shows a variant of  FIG. 1  in which the guide segments  17   b  are designed to be particularly long and in which the entire guide head is pivotably held by a deflecting means  16  which acts as a support. The deflecting means  16  is controlled, as known per se (i.e. pipe in PS Powerstrip 9500), by a suitable mechanism or by, for example, a motor, pneumatic or electromagnetic drive and is driven in such a way that the longitudinal axis of the universal guide is present on the one hand in the cable axis and is oblique thereto in the swivelled-out state. The deflecting means is connected by means of metal retaining plates  20  and socket-head cap screws  15  to an extended retaining part  21  of the scale-bearing cover  5 .  
         [0053]      FIG. 3   a  showed the design according to  FIG. 3  in the assembled state.  
         [0054]      FIG. 4  shows a short guide segment  17   a  in detail with its guide segment body  4   a  and  
         [0055]      FIG. 5  shows a long guide segment  17   b  in combination with its guide segment body  4   b.    
         [0056]     The length of the segments  17  may be a multiple of the adjustable cable diameter.  
         [0057]     The actuation of the guide segments  17 ,  17   a  and  17   b  is effected similarly to the actuation of those of the clamping or centring jaws of the Applicant&#39;s machines mentioned in the introductory part of the description and is described, for example, in U.S. Pat. No. 5,010,797. Details of the actuation, such as, for example, the drives, spring return travel, etc., and variants thereof can be derived or adopted without problems from the prior art by a person skilled in the art. The content of U.S. Pat. No. 5,010,797 is hereby incorporated by reference in the present Application text. The pins  12 ,  13  mentioned in the figures can therefore also be replaced, for example, by lever arms ( 31  and  32 ) from  FIG. 13  of the U.S. Pat. No. 5,010,797. Solutions which make use of, for example, pins ( 11 ) and grooves ( 14 ) according to  FIG. 1  and  FIG. 2  of U.S. Pat. No. 5,010,797 are also within the scope of the invention.  
         [0058]     A version of the invention which is based on another principle is shown in  FIG. 6 , in which spring-loaded segments  22  engage one another in such a way that they enclose a variable tube space and can be caused to perform a diameter reduction by pressure from outside (arrow A), but the segments expand again to a larger diameter on reduction of the pressure. The pressure can be applied by rods, spindles or eccentric cams known per se, which are not shown here in detail. The spiral spring segments  22  may be connected to rigid segment plates  17  and thus seal the segment plates  17  against one another.  
         [0059]     A further somewhat different principle is evident from  FIG. 7 , in which a single elongated spiral spring  23  is used as a guide tube. This spring  23  is designed so that it tends to open to the largest internal diameter. When pressure is applied from outside (arrow B), the internal diameter decreases by virtue of the fact that the inner end of the spiral spring  23  is displaced or rolled in along the spring wall in the closing direction. Thus, the spiral spring  23  may have its internal diameter adjusted by the action of an outside force. In these versions, the spiral spring segments  22  or the elongated spiral spring  23  can be operated in such a way that the inner end or ends of the spring  23  or the segments  22  rests against the inner wall of the spiral spring  23  or rest against the inner wall of an adjacent spiral spring segment  22  or slides along said wall on adjustment. The spiral spring segments  22  or the spiral spring  23  may be composed of conventional spring steels or of plastic, particularly fibre-reinforced plastic.  
         [0060]     A further version is shown schematically in  FIG. 8 , in which a broad spring  24  serves as a guide tube and is based on the principle of a loop. One end of the spring  25  passes through the other spring end  26 , through a slit so as to intermesh, the two ends being formed in a comb-like manner. The diameter of the guide can thus be adjusted over wide ranges by a tensile force (arrow C) at the two spring ends  25 ,  26 . If it is intended for the centre of the guide always to remain in the same position, the tensile force at both spring ends  25  and  26  must be applied symmetrically and a diameter reduction must additionally be compensated by a lateral displacement of the entire structure (transverse arrow D). Thus, as described in the foregoing paragraphs, in several versions of the invention the tube wall is designed to be flexible and may be stretched or compressed.  
         [0061]     After a study of these exemplary data, various specific possible implementations will automatically occur to a person skilled in the art so that these details will not be explained in more detail here.  
         [0062]      FIG. 9  shows a further version of a radially adjustable cable guide. This has three guide rollers  28  radially adjustable in the direction of the arrows “E” and guide plates  29  connected to said rollers. The guide plates  29  preferably consist of elastic spring steel and are connected to the guide rollers, for example, by welding or riveting. The radius of curvature R of the guide plates  29  corresponds approximately to half the diameter d of the smallest cable  27  to be held. In the case of larger cable diameters, the guide plates  29  can thus adapt in terms of the radius R to the external diameter of the cable. The free ends of the guide plates  29  are rolled up or bent over in order to avoid damage to the surface of the cable by sharp edges.  
         [0063]     The perspective  FIG. 10  and  FIG. 11  shown as an exploded diagram show a further possibility for an adjustable cable guide. There, guide segments  34  are in each case mounted at both ends by means of journals  35 . A toothed segment  33  having teeth is mounted on each of these guide segments. The teeth of the toothed segment  33  engage from the inside a toothed ring  31  which is rotatably mounted in a housing  30 . A pin  38  which is movable in a recess  36  in the housing  30  is fixed radially on the outside of the toothed ring  31 . Two coaxial adjusting screws  39  are arranged in such a way that they pass through the housing  30 , their free ends coming to a stop loosely on one side each of the pin  38 . If the adjusting screws  39  are displaced axially in diametrically opposite directions, the toothed ring  31  is rotated by means of the pin  38 . This in turn drives the displaceably mounted guide segments  34  by means of the toothed segments  33 . Thus, the adjustment of displaceably mounted guide segments  34  may be effected by rotation of toothed ring  31  via teeth engaging therein, or toothed segments  33  of the guide segments  34 . The size of the recess  36  in the housing  30  determines the maximum angle of rotation and hence the smallest and largest possible diameter of the cable guide. Securing screws  40  serve for fixing the adjusting screws  39 . All the guide segments  34  are arranged in a casing  37 . A cover  32  which closes the housing  30  is fixed by means of hexagon socket head screws  41 .  
         [0064]     Advantageously, a funnel-shaped, preferably conically tapering infeed region ( 19   a ) may be located upstream of the adjustable guide region in the several versions of the invention.  
         [0065]     In all versions of the invention, adjustment may be effected by a motor—in particular electronically—so that an operator or a sensor—controlled controller sets the respective required internal tube diameter. Thus, a control may be provided, with the aid of which the cable information—either detected by sensors or input be programming—automatically sets the correct diameter. In the versions of the invention, the adjustment of the segments and/or of the elastic tube wall segments or tube wall elements may be effected by hydraulic or pneumatic actuators or by means of contact with a pressure medium.  
         [0066]     The following list of reference numerals is part of the description. The assemblies, devices and details mentioned in the Patent Claims are considered also to have been disclosed in the description. The spirit and scope of the appended claims should not be limited to the description of the preferred versions contained herein.  
       LIST OF REFERENCE SYMBOLS  
       [0000]    
       
           1 —Guide holder  
           2 —Cam plate  
           3 —Cover  
           4   a, b —Guide segment body  
           5 —Scale-bearing cover  
           6 —Sliding bearing  
           7 —Knurled nut  
           8 —Spring-loaded thrust piece  
           9 —Threaded pin  
           10 —Socket-head cap screw  
           11 —Socket-head cap screw  
           12 —Straight pin  
           13 —Straight pin  
           14 —Hexagon nut  
           15 —Socket-head cap screw  
           16 —Deflecting means  
           17 ,  a, b —Guide segment  
           18 —Guide slot  
           19 —Casing  
           20 —Metal retaining plate  
           21 —Retaining part  
           22 —Spring-loaded segments  
           23 —Spiral spring  
           24 —Broad spring  
           25 —One spring end  
           26 —Other spring end  
           27 —Cable  
           28 —Adjustable guide roller  
           29 —Guide plate  
           30 —Housing  
           31 —Toothed ring  
           32 —Cover  
           33 —Toothed segment  
           34 —Guide segment  
           35 —Journal  
           36 —Recess  
           37 —Casing  
           38 —Pin  
           39 —Adjusting screw  
           40 —Securing screw  
           41 —Hexagon socket head screw