Abstract:
A cable connector for receiving a cable and a connector block. The cable connector including a first shell element with a first strain relief holding feature, a first connector block receiving feature, and a recess; a second shell element with a second strain relief holding feature, a second connector block receiving feature, and a projection; and a strain relief element defining a cable aperture sized to receive the cable, a compression collar, and a wing portion. The projection is received within the recess. The first and second strain relief holding features cooperate to support and maintain the strain relief element. The first and second connector block receiving features cooperate to support and maintain the connector block. The wing portion of the strain relief element is arranged to increase a holding ability of the strain relief element when a twisting or axial force is applied to the cable.

Description:
BACKGROUND 
     The present invention is directed to cable connectors for use with control systems. More specifically, the invention is directed to multi-pin cable connectors and their assembly. 
     Typically, multi-pin connectors are overmolded with a resin or other hard setting material. This overmolding surrounds all conductors in the cable and is in positive contact with the wires, pins, and sheathing. Such cables are mass produced and customization is limited. For example, pin/wire positions are set and may not be changed. 
     Existing cable connectors are provided with both ends of the cable terminating in an overmolded cable connector. For custom installations in a control environment, one end is often cut off to expose the individual wires. This operation introduces inefficiency and calculated loss. 
     BRIEF SUMMARY OF THE INVENTION 
     The present embodiments overcome the aforementioned problems by providing first and second shell elements and a strain relief element. The invention can be assembled and used without any overmolding, fasteners, or adhesives. 
     In one construction, the invention provides a cable connector for receiving a cable and a connector block. The cable connector includes: a first shell element that includes a first strain relief holding feature, a first connector block receiving feature, and a recess; a second shell element that includes a second strain relief holding feature, a second connector block receiving feature, and a projection; and a strain relief element that defines a cable aperture sized to receive the cable, a compression collar, and a wing portion. The projection of the second shell element is received within the recess of the first shell element, the first strain relief holding feature and the second strain relief holding feature cooperate to support and maintain the strain relief element in the cable connector, the first connector block receiving feature and the second connector block receiving feature cooperate to support and maintain the connector block in the cable connector, and the wing portion of the strain relief element is arranged to increase a holding ability of the strain relief element when a force is applied to the cable. 
     In another construction, the invention provides a method of assembling a cable connector to a cable and a connector block, wherein the cable connector includes: a first shell element with a first strain relief holding feature, a first connector block receiving feature, and a recess; a second shell element including a second strain relief holding feature, a second connector block receiving feature, and a projection; and a strain relief element defining a cable aperture sized to receive the cable, a compression collar, and a wing portion. The method includes inserting the cable through the cable aperture, wiring the cable to the connection block, positioning the strain relief element between the first shell element and the second shell element, positioning the connection block between the first shell element and the second shell element, engaging the strain relief element with the first strain relief holding feature and the second strain relief holding feature, inserting the projection of the second shell element into the recess of the first shell element, and sonic welding the first shell element to the second shell element. 
     In another construction, the invention provides a prewired cable assembly that includes a cable with a plurality of wires and a sheathing, and a connector block with a plurality of connection elements, each connection element in electrical communication with one of the plurality of wires and insulated from the other connection elements. A first shell element includes a first strain relief holding feature, a first connector block receiving feature, and a recess. A second shell element includes a second strain relief holding feature, a second connector block receiving feature, and a projection. A strain relief element defines a cable aperture sized to receive the cable, a compression collar, and a wing portion. The projection of the second shell element is received within the recess of the first shell element, the first strain relief holding feature and the second strain relief holding feature cooperate to support and maintain the strain relief element in the cable connector, the first connector block receiving feature and the second connector block receiving feature cooperate to support and maintain the connector block in the cable connector, and the wing portion of the strain relief element is arranged to increase a holding ability of the strain relief element when a force is applied to the cable. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The invention will be better understood and features, aspects and advantages other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such detailed description makes reference to the following drawings. 
         FIG. 1  is an exploded perspective view of a cable assembly, a Programmable Logic Controller (PLC), and an I/O board. 
         FIG. 2  is a front perspective view of a connector according to an embodiment of the invention. 
         FIG. 3  is a rear perspective view of the connector of  FIG. 2 . 
         FIG. 4  is a front view of the connector of  FIG. 2 . 
         FIG. 5  is a rear view of the connector of  FIG. 2 . 
         FIG. 6  is a left side view of the connector of  FIG. 2 . 
         FIG. 7  is a right side view of the connector of  FIG. 2 . 
         FIG. 8  is a top view of the connector of  FIG. 2 . 
         FIG. 9  is a bottom view of the connector of  FIG. 2 . 
         FIG. 10  is a section view of the connector of  FIG. 2  taken along line  10 - 10  in  FIG. 8 . 
         FIG. 11  is a plan view of a connection profile of the connector of  FIG. 2 . 
         FIG. 12  is a perspective view of a first shell element of the connector of  FIG. 2 . 
         FIG. 13  is a perspective view of a second shell element of the connector of  FIG. 2 . 
         FIG. 14  is a perspective view of a strain relief element of the connector of  FIG. 2 . 
         FIG. 15  is a section view of the strain relief element of  FIG. 14  taken along line  15 - 15 . 
         FIG. 16  is a front view of the strain relief element of  FIG. 14 . 
         FIG. 17  is a top view of the strain relief element of  FIG. 14 . 
         FIG. 18  is an exploded view of the connector of  FIG. 2 . 
         FIG. 19  is a perspective view of another connector according to an embodiment of the invention. 
         FIG. 20  is a perspective view of another connector according to an embodiment of the invention. 
     
    
    
     While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will be described in terms of one or more preferred embodiments, and it should be appreciated that many equivalents, alternatives, variations, and modifications, aside from those expressly stated, are possible and within the scope of the invention. 
       FIG. 1  shows an input/output (I/O) module  10  with a removable face plate  14 . The I/O module  10  includes a plurality of pins  18  and the removable face plate  14  includes a matching number of screw connections  22  that interface with the pins  18  when the removable face plate  14  is installed on the I/O module  10 . 
     A prewired cable  26  includes a cable connector  30 , a plurality of wires  34 , and a sheathing  38  surrounding the wires  34 . The cable connector  30  includes a plurality of pins (not shown) each associated and in isolated communication with a corresponding wire  34 . 
     An interface module (IFM)  42  includes a socket  46  for receiving the cable connector  30 , and a plurality of connection points  50 . The socket  46  includes a plurality of pin receiving sockets (not shown), each associated with a pin of the cable connector and in communication with a corresponding connection point  50 . 
     The prewired cable  26  is arranged such that individual wires  34  may be wired as desired to the screw connections  22  of the I/O module  10  and easily communicated to the IFM  42  via the cable connection  30  and the socket  46 . Such an arrangement simplifies a wiring cabinet or enclosure and makes instillation more reliable while increasing installation speed. Numerous advantages exist for using prewired cables, as is well known in the art. 
     Turning to  FIG. 2 , an exemplary inventive cable connector  54  is illustrated. The cable connector  54  includes a first shell element  58 , a second shell element  62 , and a strain relief element  66 . The first and second shell elements  58 ,  62  may be constructed of Valox  357  or other U/L recognized material for electrical connectors. 
       FIG. 12  shows the first shell element  58  in detail. The first shell element  58  includes a front or connection aperture  70  arranged to receive a pin block, or another connection block  71  such as a pin receiving block (see  FIG. 18 , the connection block  71  is shown in broken lines in  FIG. 2 ). The connection block  71  includes a plurality of connection elements each associated with a single wire  34  of the cable  26  and insulated from the other connection elements. Connection blocks  71  are well known in the art and any desired block  71  may be suitably adapted for use with the inventive cable connector  54 . For example, 20 pin and 40 pin connector blocks  71  may be used. Inward from the connection aperture  70  are arranged a pair of projections  72 . When installed, the connection block  71  would abut the projections  72 . 
     The first shell element  58  also includes a bottom or cable aperture  74  arranged to receive the strain relief element  66 . Adjacent the cable aperture  74  is a collar recess  78  of slightly larger diameter than the cable aperture  74 . 
     Between the connection aperture  70  and the cable aperture  74 , a body cavity is defined by walls  82 . The space within the body cavity provides room for the connection of wires to the connection block  71 . 
     An outside surface  84  of the first shell element  58  includes a T-slot  86  arranged on a side surface substantially adjacent the connection aperture  70 . The outside surface  84  also defines a guide portion  90  that aids in the installation of the cable connector  54  into the socket  46 , and a raised rib  94  on both a top side of the outside surface  84  and an underside of the outside surface  84 . A fillet  98  is positioned between the raised ribs  94  and the outside surface  84 . 
     Coupling recesses  102  are defined in the raised ribs  94  and lined with energy concentrator ribs  106 . The illustrated energy concentrator ribs  106  are triangular in cross section and extend the full depth of the coupling recess  102 . The coupling recesses  102  terminate at a connection wall  110  adjacent the connection aperture  70  of the first shell element  58 , and in a cable wall  114  adjacent the cable aperture  74 . 
     The rightmost end of the first shell element  58  as viewed in  FIG. 12 , hereinafter referred to as the inside extremity, is not enclosed by a wall but is open. The inside extremity is defined by an inside surface  118  of the raised ribs  94 . 
       FIG. 13  shows the second shell element  62  in detail. The second shell element  62  includes a front or connection aperture  70 ′ that, together with the connection aperture  70  of the first shell element  58 , receives the connection block  71  (see  FIG. 18 ). Inward from the connection aperture  70 ′ are arranged a pair of projections  72 ′. When installed, the connection block  71  would abut the projections  72 ′. 
     The second shell element  62  also includes a bottom or cable aperture  74 ′ arranged to receive the strain relief element  66 . Adjacent the cable aperture  74 ′ is a collar recess  78 ′ of slightly larger diameter than the cable aperture  74 ′. 
     Between the connection aperture  70 ′ and the cable aperture  74 ′, a body cavity is defined by walls  82 ′. The space within the body cavity provides room for the connection of wires to the connection block  71 . 
     An outside surface  84 ′ of the second shell element  62  includes a T-slot  86 ′ arranged on a side surface substantially adjacent the connection aperture  70 ′. The outside surface  84 ′ also defines a guide portion  90 ′ that aids in the installation of the cable connector  54  into the socket  46 , and a raised rib  94 ′ on both a top side of the outside surface  84 ′ and an underside of the outside surface  84 ′. A fillet  98 ′ is positioned between the raised ribs  94 ′ and the outside surface  84 ′. 
     Projections  122  extend from the raised ribs  94 ′ and are sized to be received in the recesses  102  of the first shell element  58  and to contact the energy concentrator ribs  106 . The projections  122  are arranged such that the projections are received within the connection wall  110  and the cable wall  114 . Additionally, a cable wall  114 ′ is formed in the second shell element  62  corresponding with the cable wall  114  of the first shell element  58 . 
     The leftmost end of the second shell element  62  as viewed in  FIG. 13 , hereinafter referred to as the inside extremity, is not enclosed by a wall but is open. The inside extremity is defined by an inside surface  126  of the raised ribs  94 ′. The inside surface  118  of the first shell element  58  abuts the inside surface  126  of the second shell element  62  when the cable connector  54  is assembled. 
       FIG. 14  shows the strain relief element  66  in detail. The strain relief element  66  includes a cable aperture  132  sized to receive the cable  26 , two wing portions  136 , a compression ring portion  142 , and a flexible skirt  146 . The cable aperture  132  is sized such that the sheathing  38  of the cable  26  is in an interference fit relationship with the cable aperture  132 . That is to say, a force must be used to install the strain relief element  66  onto the cable  26 . The cable aperture  132  is sized for a specific cable  26  such that the interference fit can be controlled. 
     The wing portions  136  define a top surface  150  of the strain relief element  66  and extend to a wing diameter  154  that can be concentric with the cable aperture  132 . From the wing diameter  154 , the wing portions  136  extend downward at an oblique angle to the compression ring portion  142 . A front surface  158  and a back surface  162  of the strain relief element  66  are shaped such that they fit within the body cavity of the first and second shell elements  58 ,  62  when the cable connector  54  is assembled (see  FIG. 10 ). 
     The compression ring portion  142  defines a diameter that is larger than a diameter of the collar recesses  78 ,  78 ′ of the first and second shell elements  58 ,  62  when the cable connector  54  is assembled. A height of the compression ring portion  142  is arranged to substantially fit within a height of the collar recesses  78 ,  78 ′ of the first and second shell elements  58 ,  62 . 
     Below the compression ring portion  142  is formed a recess  166  that receives the cable walls  114 ,  114 ′ of the first and second shell elements  58 ,  62  when the cable connector  54  is assembled to maintain the strain relief element  66  in the assembly. An upper surface  170  of the flexible skirt  146  abuts the bottom of the cable walls  114 ,  114 ′ of the first and second shell elements  58 ,  62  when the cable connector  54  is assembled. 
     The flexible skirt  146  defines a plurality of ribs or projections  174  and is able to flex with the movement of the cable  26  while supporting the cable  26  and providing support. 
       FIG. 19  shows an alternate construction of a cable connector  200  according to the invention. The cable connector  200  includes a first shell element  204  and a second shell element  208  coupled to a strain relief element  212  via living springs  216 . The illustrated cable connector  200  is formed as a single piece. The two shell elements  204 ,  208  are rotated into engagement as shown by the arrows in  FIG. 19 . Once engaged, the two shell elements  204 ,  208  may be sonically welded together to complete assembly of the cable connector  200 . 
       FIG. 20  shows an alternate construction of a cable connector  300  according to the invention. The illustrated cable connector  300  includes a first shell element  304  and a second shell element  308 . Each shell element includes a side aperture  312  (only the side aperture  312  of the second shell element  308  is visible). A strain relief element  316  includes two arms  320  that are sized to engage the side apertures  312  of the first and second shell elements  304 ,  308 . During assembly, the two shell elements  304 ,  308  may be brought together as shown by the arrows in  FIG. 20  and sonically welded together. As discussed above, other joining techniques and methods may be used as desired. 
     Assembly of the cable connector  54  will be described with reference to  FIG. 18 . To begin assembly, a cable  26  is selected with the desired number of conductors or wires  34  and the desired sheathing  38 . The strain relief element  66  is then forced onto the cable sheathing  38 . The cable aperture  132  should snugly engage the sheathing  38 . The wires  34  are then fixed to the desired pins on the connection block  71 . 
     With the connection block  71  wired and the strain relief element  66  mounted on the sheathing  38 , the first and second shell elements  58 ,  62  are brought together from opposing directions to close around the strain relief element  66 , the wires  34 , and the connection block  71 . The recess  166  of the strain relief element  66  is engaged by the cable walls  114 ,  114 ′ of the first and second shell elements  58 ,  62  while the compression ring portion  142  is compressed by the collar recesses  78 ,  78 ′ of the first and second shell elements  58 ,  62 . The compression increases the friction force exerted on the sheathing and helps maintain the cable  26  in position relative to the strain relief element  66 . 
     The projections  122  of the second shell element  62  are received within the recesses  102  of the first shell element  58  with the energy concentrator ribs  106  engaging the projections  122 . When the inside surface  118  of the first shell element  58  contacts the inside surface  126  of the second shell element  62 , the joint can be sonic welded together. Other connection methods are possible. For example, an epoxy or adhesive may be used. The energy concentrator ribs  106  aid the sonic welding and provide a superior joint. 
     With the first and second shell elements  58 ,  62  sonic welded together, the assembly is complete and the cable connector  54  may be used as intended. The strain relief element  66  maintains the cable  26  in position via friction in the cable aperture  132  and via action of the wing portions  136 . When a pulling force is applied to the cable  26 , the wing portions  136  may flex inward with the pulling force, thereby applying a large friction force and constricting about the cable  26 . Further, a twisting action on the cable  26  will cause the wing portions  136  to flex and also increase the friction force, thereby resisting movement. This flexing action inhibits removal or slippage of the cable  26 . 
     The above described invention provides an easily customizable cable connector. The body cavity within the first and second shell elements  58 ,  62  may not be filled with polymer or other substance and is not subject to electrical crossover, interference, or accidental conduction between wires  34  or pins. The cable connector  54  is easy to assemble for various connector blocks or pin arrangements. Further, the diameter of cable used with the cable connector  54  can easily be changed by simply altering the diameter of the cable aperture  132  in the strain relief element  66 . 
     Several other views of exemplary cable connectors are provided.  FIG. 3  is a rear perspective view of the cable connector  54 .  FIG. 4  is a front view of the cable connector  54 .  FIG. 5  is a rear view of the cable connector  54 .  FIG. 6  is a left side view of the cable connector  54 .  FIG. 7  is a right side view of the cable connector  54 .  FIG. 8  is a top view of the cable connector  54 .  FIG. 9  is a bottom view of the cable connector  54 .  FIG. 10  is a section view of the cable connector  54  taken along line  10 - 10  in  FIG. 8 .  FIG. 11  is a plan view of a connection profile of the cable connector  54 .  FIG. 15  is a section view of the strain relief element  66 .  FIG. 16  is a front view of the strain relief element  66 .  FIG. 17  is a top view of the strain relief element  66 . 
     In other constructions, the cable connector  54  could have a different outward appearance, or be a straight connector. Other constructions are possible in view of the following claims.