Abstract:
A cable compression die assembly is used in connection with a compression tool for compressing a stranded cable prior to crimping. Upper and lower compression dies each have a semicircular groove to compress the cable. A plurality of extending blocks guides each die into sliding engagement. The stranded cable will be compressed between the upper and lower compression dies to a reduced cable radius. Compressing generally reduces or eliminates air spaces between the stranded cable wire strands. A subsequent crimp connection forms a nearly monolithic structure to maximize current flow between two crimp connected compressed stranded cables.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Patent Application No. 62/189,514, filed on Jul. 7, 2015, the contents of which are incorporated herein by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention is directed to crimping wire cables and, more particularly, is directed to an apparatus and method for compressing wire cable strands prior to crimping. 
       BACKGROUND OF THE INVENTION 
       [0003]    Crimp connections are widely used in industry to connect two electrical conductors or wire cables together. Crimp connections are also used to fasten a ring lug or spade lug to the end of a single cable. The cable or cable pair is inserted into the cable crimp connector, which is then compressed tightly around the cable with a compression tool. With small gauge wire strand cable, the tool is typically manually squeezed to compress the cable connector. In the case of large gauge wire strand cable, the compression tool is typically operated by mechanical leverage or hydraulic pressure. 
         [0004]      FIGS. 1-3  show a compression tool  44  having a fixed anvil, or upper jaw  46 ; and a movable spindle, or lower jaw  48 . It is to be understood that the compression tool  44  can be oriented in any position, vertical, horizontal, angled, the upper and lower portions reversed, and that these orientations are equivalent for the purposes disclosed herein. Crimping dies are installed in the compression tool  44 . An upper crimp die  26  is mounted in the upper jaw  46 . A lower crimp die  28  is mounted in the lower jaw  48 . In  FIG. 1 , a C-shaped cable connector  30  is disposed in the lower crimp die  28 . Upper  42  and lower  42  multi-strand wire cables are received in the cable connector  30 . Each cable  42  comprises multiple individual wires  36 . In  FIG. 2 , the lower jaw  48  is raised until the cable connector  30  contacts the upper crimp die  26 . In  FIG. 3 , the lower jaw  48  is raised with force, until the cable connector  30  is squeezed around the cables  42 . The resultant connection is shown in  FIG. 4 . Numerous air pockets or spaces  38  may exist between the wires  36 . Air spaces  38  may be present around the outer periphery of each cable, between the wire strands and the cable connector  30 . These air spaces  38  could reduce the current carrying capacity of the connection. 
       SUMMARY OF THE INVENTION 
       [0005]    In one aspect, a cable compression die assembly is used for compressing a stranded cable for subsequent termination in a cable connector. The cable compression die assembly comprises a pair of cable compression dies for directly accommodating the stranded cable therebetween. The dies are accommodated within a compression tool. The dies are compressingly closable about the stranded cable by the compression tool. This will reduce spaces between strands of the stranded cable. 
         [0006]    In another aspect, an assembly terminates a stranded cable to a cable connector. The assembly comprises an operable compression tool. A pair of cable compression dies is insertable into the compression tool for compression of the stranded cable. This will reduce spaces between strands of the stranded cable. A pair of connector crimping dies is insertable into the compression tool. The dies receive the cable connector and the compressed stranded cable therebetween for crimping the cable connector to the compressed stranded cable. 
         [0007]    In yet another aspect, a method of terminating a stranded cable to a cable connector comprises the steps of providing a compression tool. A pair of cable compression dies is inserted into the compression tool. The stranded cable is inserted between the cable compression dies. The stranded cable is compressed between the cable compression dies with the compression tool. This will reduce spaces between wire strands of the stranded cable. The compressed stranded cable is removed from the compression tool. 
         [0008]    The cable compression dies are removed from the compression tool. A pair of connector crimping dies is inserted into the compression tool. The cable connector is inserted between the connector crimping dies. The compressed stranded cable is inserted into the cable connector. The cable connector is crimped about the compressed stranded cable using the compression tool. 
         [0009]    These and other aspects, objectives, features, and advantages of the disclosed technologies will become apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a front elevational view of a prior art compression tool used in connection with the disclosed technologies, showing a cable connector, crimp dies, and two cables. 
           [0011]      FIG. 2  is a front elevational view of the prior art compression tool of  FIG. 1 , showing the upper and lower jaws moving toward one another. 
           [0012]      FIG. 3  is a front elevational view of the prior art compression tool of  FIG. 1 , showing the crimping. 
           [0013]      FIG. 4  shows a prior art connection having numerous air spaces in between the wire strands and between the cables and the cable connector. 
           [0014]      FIG. 5  shows a connection made with the invention and having minimal air spaces in between the wire strands and between the cables and the cable connector. 
           [0015]      FIG. 6  is a cross-sectional view of a wire strand cable before compression. 
           [0016]      FIG. 7  is a cross-sectional view of a wire strand cable after compression. 
           [0017]      FIG. 8  is a front exploded perspective view of a cable compression die assembly constructed in accordance with the invention. 
           [0018]      FIG. 9  is a front contracted perspective view of the cable compression die assembly of  FIG. 8 . 
           [0019]      FIG. 10  is a top perspective view of a lower compression die of the cable compression die assembly of  FIG. 8 . 
           [0020]      FIG. 11  is another top perspective view of the lower compression die of the cable compression die assembly of  FIG. 8 . 
           [0021]      FIG. 12  is a bottom perspective view of an upper compression die of the cable compression die assembly of  FIG. 8 . 
           [0022]      FIG. 13  is another bottom perspective view of the upper compression die of the cable compression die assembly of  FIG. 8 . 
           [0023]      FIG. 14  is a front elevational view of the lower compression die of the cable compression die assembly of  FIG. 8 . 
           [0024]      FIG. 15  is a right side elevational view of the lower compression die of the cable compression die assembly of  FIG. 8 . 
           [0025]      FIG. 16  is a left side elevational view of the lower compression die of the cable compression die assembly of  FIG. 8 . 
           [0026]      FIG. 17  is a top plan view of the lower compression die of the cable compression die assembly of  FIG. 8 . 
           [0027]      FIG. 18  is a front elevational cross-sectional view of the lower compression die of the cable compression die assembly of  FIG. 8 , taken along lines  18 - 18  of  FIG. 17 . 
           [0028]      FIG. 19  is a front elevational cross-sectional view of the lower compression die of the cable compression die assembly of  FIG. 8 , taken along lines  19 - 19  of  FIG. 17 . 
           [0029]      FIG. 20  is a front elevational view of the cable compression die assembly of  FIG. 8  with a cable before compression, showing the dies open. 
           [0030]      FIG. 21  is a front elevational view of the cable compression die assembly of  FIG. 8  with a cable before compression, showing the dies starting to close. 
           [0031]      FIG. 22  is a front elevational view of the cable compression die assembly of  FIG. 8  with a cable during compression, showing the wire strands pushed inward. 
           [0032]      FIG. 23  is a front elevational view of the cable compression die assembly of  FIG. 8  with a cable after compression. 
           [0033]      FIG. 24  is a cross-sectional view of a connection made with the invention and showing the wire strands and the cables and the cable connector formed into a monolithic structure. 
           [0034]      FIG. 25  is a front elevational view of the compression tool used with the invention, a cable connector, crimp dies, and two compressed stranded cables, showing the start of the connection process. 
           [0035]      FIG. 26  is a front elevational view of the compression tool used with the invention, a cable connector, crimp dies, and two compressed stranded cables, showing the connection process partly completed. 
           [0036]      FIG. 27  is a front elevational view of the compression tool used with the invention, a cable connector, crimp dies, and two compressed stranded cables, showing the connection process completed. 
       
    
    
       [0037]    It should be noted that the drawings herein are not to scale. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0038]    Describing now in further detail these exemplary embodiments with reference to the  FIGS. 5-24 , as well as  FIGS. 1-4  as described above. The present invention employs the compression tool  44  shown in  FIGS. 1-4  to pre-compress stranded cable  42  using a cable compression die assembly  40 , so as to reduce the spaces  38  between the strands  36  of the cable. Thereafter, the compression tool  44  is used to terminate the connector  30  to the compressed cable  32 ,  34  using connector crimp dies  26 ,  28  to form a superior connection between the cable  32 ,  34  and the connector  30 . 
         [0039]    The compression tool  44  has an upper jaw  46  and a lower jaw  48  adapted for moving toward one another. The cable  42  has a predetermined cable first radius R 1  prior to compressing, as shown in  FIG. 6 . The cable  42  has a predetermined cable second radius R 2  after compressing, as shown in  FIG. 7 . Note that after compression the air spaces in between the wire strands are greatly reduced in size, or eliminated. 
         [0040]    The cable compression die assembly  40  comprises a lower compression die  50  having a lower groove  52  semicircular about a lower axis  54 . The lower groove  52  has a radius generally equal to the cable second radius R 2 . The lower groove  52  is adapted to receive and compress the cable  42 . The lower compression die  50  is adapted for mounting in the compression tool lower jaw  48 . 
         [0041]    An upper compression die  70  has an upper groove  58  semicircular about an upper axis  74 . The upper groove  58  has a radius generally equal to the cable second radius R 2 . The upper groove  58  is adapted to receive and compress the cable  42 . The upper compression die  70  is adapted for mounting in the compression tool upper jaw  46  opposite the lower compression die  50  so that the lower axis  54  and the upper axis  74  are generally parallel. 
         [0042]    Upon moving the lower jaw  48  and the upper jaw  46  toward one another, the lower compression die  50  and the upper compression die  70  will move toward one another in a closing direction  66 . The lower axis  54  and the upper axis  74  will converge, as shown in  FIG. 9 . The cable  42  will be compressed between the lower compression die  50  and the upper compression die  70  to the cable second radius R 2 . This will generally reduce or eliminate air spaces  38  between the wire strands  36 . The cross-sectional area of the lower and upper grooves  52 ,  58  of the fully closed compression die assembly  40  is approximately equal to the cross-sectional area of all the wire strands  36  of the stranded cable  42  added together. 
         [0043]      FIG. 5  shows a pair of cables  32 ,  34  which have been first compressed by the invention, then crimped into a crimp connection. Notice only a small number of reduced air pockets or spaces  38  are visible. Hence, the connection has reduced air spaces. This connection can now carry more current than the prior art connection, because of greater surface contact between the wire strand conductors  36 . 
         [0044]    As shown in  FIGS. 10-11 , the lower compression die  50  includes a plurality of lower guide blocks  56  extending upward from the lower compression die  50  in the closing direction  66 . The lower guide blocks  56  have lower terminal ends  58  disposed above the lower axis  54 . The lower terminal ends  58  are generally planar, or flat, meaning approximately lying in a plane, but not perfectly planar. The lower terminal ends  58  are generally perpendicular, or transverse, to the closing direction  66 , meaning approximately at right angles, but not perfectly ninety degrees. The lower compression die  50  has lower base flats  60  disposed below the lower axis  54  and generally parallel to the lower terminal ends  58 . Generally parallel means flat and spaced apart, not perfectly parallel. The lower base flats  60  are generally planar and generally perpendicular to the closing direction  66 . 
         [0045]    As shown in  FIGS. 12-13 , the upper compression die  70  includes a plurality of upper guide blocks  76  extending downward from the upper compression die  70  in the closing direction  66 . The upper guide blocks  76  have upper terminal ends  78  disposed below the upper axis  74 . The upper terminal ends  78  are generally planar and generally perpendicular to the closing direction  66 . The upper compression die  70  has upper base flats  80  disposed above the upper axis  74  and generally parallel to the upper terminal ends  78 . The upper base flats  80  are generally planar and generally perpendicular to the closing direction  66 . 
         [0046]    A pair of the upper guide blocks  76  is adapted to straddle and slidingly engage a one of the lower guide blocks  56 . Similarly, a pair of the lower guide blocks  56  is adapted to straddle and slidingly engage a one of the upper guide blocks  76 . This occurs upon moving the lower compression die  50  and the upper compression die  70  toward one another. This will serve to guide the lower  50  and upper  70  compression dies into alignment together axially. The upper guide block upper terminal ends  78  are adapted to contact the lower compression die lower base flats  60  and the lower guide block lower terminal ends  58  are adapted to contact the upper compression die upper base flats  80  to delimit the moving toward one another. Thus, the upper  78  and lower  58  terminal ends will establish a solid purchase upon the upper  80  and lower  60  base flats as the upper  70  and lower  50  dies contact one another. This limit is essential to preclude overcompressing the cable which could extrude cable material in an axial direction. The limit also serves to preclude damaging the dies. 
         [0047]    The lower compression die  50  includes a plurality of lower outward facets  62  that are beveled and face outward, generally away from the lower axis  54 . The lower guide blocks  56  have a plurality of lower inward facets  64  that are beveled and face inward generally toward the lower axis  54 . 
         [0048]    The upper compression die  70  includes a plurality of upper outward facets  82  that are beveled and facing outward generally away from the upper axis  74 . The upper guide blocks  76  have a plurality of upper inward facets  84  that are beveled and face inward generally toward the upper axis  74 . 
         [0049]    The upper compression die upper outward facets  82  are adapted to engage the lower guide blocks lower inward facets  64  and the lower compression die lower outward facets  62  are adapted to engage the upper guide blocks upper inward facets  84 . In the event that the dies are not precisely aligned in the compression tool  20 , the upper  84  and lower  64  inward facets will guide the upper  70  and lower  50  compression dies into alignment together transversely. In the event that the dies are precisely aligned in the compression tool, the upper  84  and lower  64  inward facets will touch as the dies reach the limit of moving together in the closing direction  66 . Furthermore, it often happens that one or more wire strands  36  are bent or displaced outward away from the cable  42  sufficiently that they will not fit into the cable compression die. In these cases, the upper  84  and lower  64  inward facets are adapted to push outward displaced wire strands  36  inward toward the cable  42  so that the wire strands  36  are closely adjacent, in preparation for compression. Closely adjacent means all strands of the multiple stranded wire cable are sufficiently close to one another that the cable will fit into the cable compression die in preparation for compressing. Yet furthermore, the upper  84  and lower  64  inward facets are adapted to guide the cable  42  into the upper  72  and lower  52  grooves for compression. The compression die assembly  40  is circumferentially closed as the compression of the stranded cable  42  begins. Thus, no stray outward displaced wire strands  36  can escape compression in the compression die assembly  40 . 
         [0050]    After compression of two stranded cables  42 , the resultant compressed cables are ready to be connected together in the crimp connector  30 . As shown in  FIG. 25 , the upper crimp die  26  is mounted in the compression tool upper jaw  46 . The lower crimp die  28  is mounted in the compression tool lower jaw  48 . The crimp connector  30  is inserted into the upper  26  and lower  28  crimp dies. The first compressed cable  32  is received in the upper portion of the connector  30 . The second compressed cable  34  is received in the lower portion of the connector  30 . As shown in  FIG. 26 , the compression tool upper jaw  46  and lower jaw  48  are brought together and are beginning to close the connector  30  around the first  32  and second  34  compressed cables. As shown in  FIG. 27 , the compression tool upper jaw  46  and lower jaw  48  are brought together with great force to fully close and compress the connector  30  around the first  32  and second  34  compressed cables. 
         [0051]    The air spaces  38  between the wire strands  36  are greatly reduced and generally or almost eliminated. Generally eliminating air spaces means the included air spaces after compression and crimping are fewer than with crimping alone. Generally eliminating air spaces can also be defined to mean minimizing air spaces. 
         [0052]    The structure of the resultant connection is generally or nearly monolithic, as shown in  FIG. 24 . A generally monolithic structure means that air spaces have been minimized or eliminated between individual wire strands of a multiple stranded wire cable. A generally monolithic structure does not mean perfectly homogeneous in structure or density, since in practice, there will exist small spaces in the structure. A generally monolithic structure Can also be defined to mean solid, but with the understanding that it is not perfectly solid, and may include air spaces. The electrical connection can now carry increased current in comparison with the prior art connection. 
         [0053]    In the preferred embodiment shown, the upper  70  and lower  50  compression dies are identical to one another. Furthermore, the die assembly  40  can be oriented in any direction. The preferred embodiment shows a vertical orientation with the compression tool upper jaw  46  at the top and the lower jaw  48  at the bottom of  FIGS. 1-3 . The die assembly  40  is shown in the Figures with the upper compression die  70  at the top, and the lower compression die  50  at the bottom. It is to be understood that the compression tool  44  and the die assembly  40  and the upper  70  and lower  50  compression dies can be oriented in any position, vertical, horizontal, angled, the upper and lower portions reversed, and that these orientations are equivalent within the spirit and scope of the claims. 
         [0054]    Although the invention has been described in detail above, it is expressly understood that it will be apparent to persons skilled in the relevant art that the invention may be modified without departing from the spirit of the invention. Various changes of form, design, or arrangement may be made to the invention without departing from the spirit and scope of the invention. Therefore, the above mentioned description is to be considered exemplary, rather than limiting, and the true scope of the invention is that defined in the following claims.