Abstract:
A cable connector which includes a concave housing having opposed planar sides and a relation between the planar sides and having a proximate opening and a distal opening and first and second interior axial walls. A cable extends through the proximate opening in the exterior wall of the concave housing toward the distal opening and diverges adjacent the distal opening of the housing into opposed first and second transverse cable extensions. A terminal block is mounted in the distal opening of the housing having first and second projections and each of the projections engage one of the interior axial walls of the housing and one of the transverse cable extensions. Metallic contacts also extend from the terminal block to be electrically connected to the transverse cable extensions.

Description:
This application is a 371 of PCT/US98/01876 Jan. 30, 1998 which claims benefit of 60/031/312 Jan. 30, 1997. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is related to electrical connectors and more particularly to cable connectors. 
     2. Brief Description of Prior Developments 
     FIG. 1 shows the current method of making a charger cable connector. This prior art charger cable connector kit includes a top cover  10 , a bottom cover  12 , a V-90 male connector  14 , a paddle board  16  and a cable  18 . It also includes lateral latches  20  and  22  and buttons  24  and  26 . To achieve the strain relief, a flexible grommet is molded onto the cable. 
     To grip the grommet, a two piece cover is used, that is closed around the grommet, and secured by screwing or riveting the two covers together, trapping the grommet, the terminal block, and the cable connector metal latches. 
     When the cable is pulled, the force is transmitted from the copper wires, through the insulation, to the grommet. The grommet then transmits the force to the cover body. The cover body transmits the force to the metal latches, which transmit the force to the body of the mating connector which, for this connector, is located in the case of a mobile telephone. This procedure avoids a situation in which force is transmitted to either the solder joints or the contacts. 
     The grommet does not prevent all forces from being transmitted to the solder joints or contacts particularly when the cable is flexed. Sometimes, however, a paddle board is used to further relieve the forces which will be transmitted to an individual contact to spread the forces over a larger number of electrically non-functional contacts. 
     The paddle board is used particularly with miniature connectors, where the strength and retention of the contact in the housing is small compared to the forces which can be applied to the cable in the use of such a product. 
     Disadvantages of the above described apparatus are as follows. 
     The number of components used means a high investment in tooling, a high material cost, and a labor intensive assembly process. 
     For a cable type B to work effectively, the adhesion between the copper wires and the insulation, and the insulation and the jacket, must be extremely high. Otherwise, when the cable is pulled, the insulation and jacket will stretch, and the force will be conducted via the copper wires direct to the solder joints and contacts, resulting in either a broken solder joint, or a displaced contact or paddle board, if used. 
     If, however, the cable is made with very high insulation and jacket adhesion, it becomes very difficult to strip during the assembly process, and becomes less flexible, making it less user friendly for the end user. 
     It is an object of the present invention to provide a cable connector which avoids the above described disadvantages. 
     SUMMARY OF THE INVENTION 
     The present invention is a cable connector assembly which includes a concave housing comprising a proximate cable receiving opening and a distal terminal block opening and an interior retaining block engagement means. A cable extends axially through the proximate cable receiving opening into the concave housing. A transverse cable extension is adjacent the distal block opening. A terminal block has an axial projection and a metallic contact and is mounted in the distal retaining block opening of the concave housing such that the projection engages the interior block retaining means and the projection and contact engage the transverse cable extension. 
     Preferably, the terminal block has a primary strain relief groove, which the wire is placed into from above. The plastic housing squeezes the insulation of the wires onto the copper, holding the wire into position in the terminal block. This holds the parts in position while the wire is soldered to the contact, and also functions as a strain relief, isolating forces from the solder joint. 
     Further, when the housing is preferably fitted to the terminal block, by sliding it forward, a ramp in the cover pushes a secondary strain relief tongue towards the cable, and finally clamps the cable insulation (or jacket in the case of cable type B) firmly to the housing. Plastic barbs in the secondary strain relief tongue also exert a locally high pressure to the cable jacket, clamping the jacket to the insulation, to the copper wires. 
     The housing is also preferably held in position against the terminal block by means of a latching device. The housing is shaped at the back to provide an area where the cable is restrained in a straight length, so that any cable flexing forces will only be seen as an axial force at the point where the cable is clamped to the cover. Further, the cable exit portion of the housing is provided with a radiused edge, to avoid any cutting of the cable jacket by repeated flexing. 
     The housing also preferably incorporates plastic latches, which will transmit the forces from the cable to the mating connector. The plastic latches are molded with a bias, and are squeezed inwards while the cover is assembled to the terminal block. When the latches are released, the flanges on each side of the main latch body rest against pre-load guide in the terminal block. This ensures that the latches always have a pre-load force holding them against the terminal block, thus eliminating a large part of the effect of manufacturing tolerances on the latch depression force. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention is further described with reference to the accompanying drawings in which: 
     FIG. 1 is an exploded perspective view of a prior art charger cable connector kit; 
     FIG. 2 is a perspective view of a disassembled cable connector representing a preferred embodiment of the present invention; 
     FIG. 3 is a perspective view of a disassembled cable connector assembly representing another preferred embodiment of the present invention; 
     FIG. 4 is a top cutaway perspective view of the assembled cable connector shown in FIG. 2; 
     FIG. 5 is a side cutaway perspective view of the assembled cable connector shown in FIG. 2; 
     FIG. 6 is a side cutaway perspective view of the assembled cable connector shown in FIG. 5; 
     FIG. 7 is a plan cutaway view of the assembled cable connector shown in FIG. 6; 
     FIG. 8 is a cross sectional view through  8 — 8  in FIG. 7; 
     FIG. 9 is a detailed view of circle  9  in FIG. 8; 
     FIGS. 10 a - 10   d  are perspective views illustrating steps in the method of assembling the cable connector shown in FIGS. 2-4; and 
     FIGS. 11 a - 11   d  are perspective views illustrating steps in the method of assembling the cable connector shown in FIGS. 5-9. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 2-9, the connector assembly includes a concave housing  28  which has a planar top side  30 , a planar bottom side  32  which are connected by vertical medial wall  34 . In this housing there is proximate opening  36  and a transverse distal opening  38 . 
     Referring particularly to FIG. 7, the housing also includes an axial interior wall  40  which has a transverse projection  42  and a second spaced axial interior wall  44  which has a transverse projection  46 . The housing also includes a third axial interior wall  48  and a proximate opening seal  50 . There are also lateral latches  52  and  54 . 
     Referring particularly to FIGS. 8 and 9, the housing has a lower interior inclined surface  56  and an upper interior surface  58 . This lower interior surface  56  may be considered to be an actuator ramp as is further explained hereafter. 
     Referring to FIGS. 2-4, in the first embodiment of the connector assembly, there is a cable type A which is shown generally at numeral  60 . This cable type A includes a conductor  62  with surrounding insulation  64  and a second conductor  61  with its surrounding insulation  68 . At the distal end of the cable  60  type A it has a transverse extension  70  with a solder tail  72  and an opposed transverse extension  74  with its solder tail  76 . 
     Referring to FIGS. 5-9, the second embodiment of the cable connector is shown. It will be understood that this embodiment is essentially identical to the first embodiment except that there is a minor adaptation to accommodate the inclusion of a cable type B which is shown generally at numeral  78 . This cable type B includes four conductors  80 ,  82 ,  84  and  86  and their respective insulation layers  88 ,  90 ,  92  and  94  and an outer cable jacket  95 . At its terminal end the cable type B has parallel transverse extensions  96  and  98  and their respective solder tails  100  and  102 . In the opposed direction the cable type B also has parallel transverse extensions  104  and  106  and their respective solder tails  108  and  110 . 
     Referring again generally to FIGS. 2-9, both embodiments include a terminal block shown generally at the numeral  112 . It will be understood from the following description that these terminal blocks are essentially identical except for a minor accommodation necessary to engage the additional set of transverse extensions in the cable type B. The blocks each have an axial projection  114  with a lateral extension  116  and a spaced parallel axial projection  118  which also has a lateral extension  120 . 
     Referring particularly to FIG. 7, it will be seen that the lateral extension  116  on projection  114  engages transverse projection  42  on the axial interior wall  40  of the concave housing. It will also be seen that the lateral extension  120  on axial projection  118  engages the lateral projection  46  on the axial interior wall  44 . On both embodiments of the connector cable there is a transverse groove  122  on projection  114  which engages a transverse extension of the cable. On the cable type B embodiment there is also a second transverse groove  124  which engages the second parallel transverse extension of the cable type B. Similarly, in both embodiments there is a transverse groove  126  on projection  118  which engages the opposed transverse extension of the cable and in the cable type B embodiment there is a second groove  128  which engages the second parallel transverse extension. The terminal block also includes contacts  130  and  132  which are electrically connected to the solder tails of the transverse extensions of the cables. 
     Referring particularly to FIG. 8, the terminal block has distal openings as at opening  134  to allow electrical connection to the contacts as at  130  from the opposed side of the terminal block. 
     Referring particularly to FIGS. 2 and 5, it will also be seen adjacent grooves  122  and  124  there are convex primary strain relief features  136  and  138  for the transverse extensions of the cable. Similarly, adjacent grooves  126  and  128  there are primary strain relief features  140  and  142  which serve the same purpose for the transverse cable extensions in the opposed direction. 
     Referring again to FIGS. 2-9 generally, it will be seen that the terminal block also includes an axial tongue  144  which extends into the concave housing. This tongue  144  has a pair of spaced transverse barbs  146  and  148  which serve as secondary strain relief features as is further explained as follows. 
     Referring particularly to FIGS. 8 and 9, it will be seen that this tongue  144  is interposed between the cable  78  and the lower interior inclined surface  56  of the housing in contacting relation with both the lower surface of the housing and the cable. (While not shown with cable  60 , it will be understood that the same arrangement is used with that cable.) It will also be seen that the barbs  146  and  148  grip the insulative layer of the cable to affect a secondary strain relief function. Referring particularly to FIGS. 2-6 it will be seen that the terminal block also includes latch guide grooves  150  and  152  for receiving, respectively, latches  52  and  54 . 
     Referring to FIGS. 10 a - 11   d , a method for assembling the cable connector of the present is illustrated. In FIGS. 10 a - 10   d  the assembly of the cable type A embodiment is illustrated. The assembly of the cable type B is illustrated in FIGS. 11 a - 11   d . Except for this difference, however, the two embodiments of this method are essentially identical. 
     Referring to FIGS. 10 a  and  11   b , in the first step of this method the concave housing  28  is slid over either the cable type A  60  (FIG. 10 a ) or the cable type B  78  (FIG. 11 a ). In FIGS. 10 b  and  11   b  the second step of the method is illustrated in which the cable is stripped and its wires are spread to form transverse extensions  70  and  74  (FIG. 10 b ) or transverse extensions  70 ,  74 ,  76  and  78  (FIG. 11 b ). In FIG. 10 c , the third step in assembling the cable type A embodiment is shown in which the transverse extensions  70  and  74  are positioned in the transverse grooves  122  and  126  of projections  114  and  118 . In this step the solder tails  72  and  76  are also connected to the contacts  130  and  132 . Similarly, in FIG. 11 c  the third step in assembling the cable type B embodiment is shown in which the transverse extensions  70 ,  74 ,  96  and  98  are positioned in the grooves  122 ,  124 ,  126  and  128  and the solder tails  72  and  100  are connected to contact  130  while solder tail  76  and  102  are connected to contact  132 . The final step of this method is illustrated in FIGS. 10 d  and  11   d  in which it is shown that the lateral latches  52  and  54  on the housing are squeezed inwardly so as to allow them to slide in the pre-load guides of the terminal block. This action causes the housing to slide over the terminal block and causes the terminal block projections  114  and  118  to engage the interior walls  40  and  42  in the way shown in FIG.  7 . This action also causes the tongue  114  to engage the cable as at  78  and the lower interior inclined surface  56  in the way shown in FIGS. 8 and 9. 
     It will be appreciated that a cable connector has been provided which reduces the number of components, integrating the function of strain relief into the terminal block, and providing a secondary strain relief which is actuated by the cover during the assembly process. 
     It will also be appreciated that the cable connector described herein will be particularly useful for mobile I/O uses. 
     Those skilled in the art will appreciate that this invention may be applicable to other types of devices. In particular, an aluminum cable or a flat ribbon cable or any combination of flat and round cables may be substituted for the copper cable. It will also be appreciated that the fixture and holding means described herein may be applicable to optical cables and optical wave guides. 
     While the present invention has been described in connection with the preferred embodiments of the various figures, it is to be understood that other similar embodiments may be used or modifications and additions may be made to the described embodiment for performing the same function of the present invention without deviating therefrom. Therefore, the present invention should not be limited to any single embodiment, but rather construed in breadth and scope in accordance with the recitation of the appended claims.