Patent Document

FIELD OF THE INVENTION 
     The present invention relates to cable terminations and more particularly to duplex or two-wire cable terminations that snap into place and include snap-on cable retainers, neither of which requires twisting for locking. 
     BACKGROUND OF THE INVENTION 
     U.S. patent application Ser. No. 09/007,532 filed Jan. 15, 1998 in the name of Thomas J. Gretz for, “Snap in Cable Connector” describes a locking cable connector composed of three mating pieces that snap together and provide a connector for helically wound armored or metal clad electrical conductors. A spring steel adapter is used in conjunction with an electrical junction box to fix the location of the locking cable connector with respect to the junction box. The first piece of the snap in locking cable connector is a die cast member including at its inbound end a smooth outer cylindrical section having an outer diameter with flanges that accommodates a spring steel adapter. The second piece is a spring steel locking ring provided to receive a helically wound shielded cable that is inserted into the out end of the die cast member. The locking ring has outwardly directed tangs that allow insertion into the die cast member but restrict withdrawal thereof from the die cast member. The locking ring also has oppositely or outwardly directed tangs to receive the armored cable and to restrict its movement in the opposite or withdrawal direction. 
     The spring steel locking ring has a cut out section that permits slight compression so that the locking ring may be easily inserted into the die cast member. Once inserted, the locking ring is able to expand to the full inner diameter of the die cast member to provide a tight and secure fit. 
     SUMMARY OF THE INVENTION 
     The present invention provides a duplex connector comprising a housing and an insert in the housing that provides two inbound end apertures that conduct two armored cables to and through a single outbound end aperture. The inbound end apertures incorporate the snap in spring steel retainers of U.S. patent application Ser. No. 09/007,532 to provide a connector that allows rapid and simplified installation of a pair of armored cables into a single junction box outlet. The outbound end of the duplex connector of the present invention preferably has a smooth outer cylindrical section and includes an outer diameter with flanges that accommodates a spring steel snap-in adapter for retention of the duplex connector in a junction box. The two inbound apertures each include a spring steel retainer having outwardly extending tangs that hold it in the inbound aperture and inwardly extending tangs that retain an inserted cable and resist retraction thereof from the duplex connector. According to a preferred embodiment of the present invention, the inwardly extending tangs are oriented to guide an inserted armored cable toward the single outbound end of the duplex connector. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a blown apart view of the duplex connector of the present invention. 
     FIG. 2 is a top view of the duplex connector of the present invention. 
     FIG. 3 is a plan view of a die-cut blank that is formed into the preferred spring steel retainer of the present invention. 
     FIG. 4 is an end view of the preferred spring steel retainer of the present invention. 
     FIG. 5 is a top view of the spring steel retainer of FIG.  4 . 
     FIG. 6 is a side view of the spring steel retainer of FIG.  4 . 
     FIG. 7 is a cross-sectional view of the spring steel retainer of FIG. 4 along the line  7 — 7  of FIG.  4 . 
     FIG. 8 is an end view of the spring steel retainer of FIG.  4 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in the drawings and particularly FIGS. 1 and 2, the duplex connector  10  of the present invention comprises: a housing  12  having a generally oval or race track-shaped inbound end  14  and a cylindrical outbound end  16 ; an inbound end insert  18 ; spring steel cable retainers  20  and  22  that insert into inbound insert apertures  24  and  26 ; spring steel locking ring  28  about the outer diameter  17  cylindrical outbound end  16  and retained by flanges  19  and  21 ; and locking screw  30 . According to a preferred embodiment, of the present invention a bushing  32  is inserted into outbound end  16 . A further preferred embodiment of the present invention includes a pair of peepholes  34  that permit viewing of the interior of housing  12  to determine the presence and/or location of cable inserted into housing  12  through insert apertures  24  and  26 . 
     Housing  12 , in addition to previously described generally oval inbound end  14 , peepholes  34 , and cylindrical out bound end  16  incorporating outer diameter  17  and flanges  19  and  21  includes shoulder portions  36  whose interior surfaces  38  are smooth to guide cables inserted through inbound end  14  via insert apertures  24  and  26  toward and through internal volume  40  of cylindrical outbound end  16 . Additionally, housing  12  includes, in at least one of its relatively flat top or bottom walls  42  and  44 , a threaded hole  46  for rotational engagement of screw  30  as described hereinafter. Flange  19  has a slight inward incline to ease insertion of housing  12  into a junction box aperture and to ease the application of spring steel adapter over outer diameter  17 . Flange  21  is of a greater diameter than flange  19  to prevent over insertion of spring steel adapter  28 . 
     The various other shapes and features of housing  12  depicted in the drawings are largely matters of functional design, material minimization and manufacturability and do not materially affect the functionality of housing  12 . 
     Insert  18  comprises a binocular shape and has outer dimensions at insertion end  46  that are matched to the inner dimensions of generally oval inbound end  14  of housing  12 . End  48  of insert  18  includes a flange  50  about both insert apertures  24  and  26  that serves as a stop to limit insertion of insert  18  into inbound end  14  of housing  12 . 
     Spring steel cable retainers  22  and  24  are inserted into apertures  24  and  26  with tangs  52 A and  52 B engaging openings  54 A and  54 B in insert  18 . A complimentary set of tangs  56 A and  56 B engage matching openings opposite openings  54 A and  54 B in insert  18  (not shown). 
     FIG. 3 is a plan view of the die-cut blank  100  that is formed into spring steel cable retainers  20  and  22 . A plurality of lateral slots  102  is formed in pairs along blank  100 . Adjacent pairs of lateral slots  102  are joined by cuts  103  extending between them. U-shaped cutouts  104  are also formed in blank  100 . Blank  100  has a forward edge  124  which is positioned toward the inside of apertures  24  and  26  when installed in insert  18  and a trailing edge  126  that faces toward the outside of apertures  24  and  26  when installed in insert  18 . Both the lateral slots  102  and U-shaped cutouts  104  are positioned at staggered distances from forward edge  124 . Blank  100  also includes a triangular cut  106  positioned near trailing edge  126  and an aperture  108  that is used to hold blank  100  during the manufacturing process when blank  100  is formed into tubular spring steel retainers  24  and  26 . When blank  100  is formed into its tubular shape, tongue  114  partially enters groove  116  formed on the opposite end of blank  100 . Lateral slots  102  and cuts  103  define staggered tangs  110 A,  110 B and  110 C that are positioned at varying precalculated distances from forward edge  124 . 
     FIG. 4 is an end view of spring steel retainers  20  or  22  from trailing edge  126  after blank  100  has been formed into its tubular shape. A gap  118  remains between the two ends of retainer  20  or  22  where tongue  114  approaches but does not contact groove  116 . The purpose of gap  118  is to impart a collapsible action to spring steel retainer  20  or  22  so that slight pressure on the outer periphery thereof will collapse it thereby allowing it to enter apertures  24  and  26  and interact with openings  54 A and  54 B in apertures  24  and  26  when inserted therein. 
     FIG. 4 depicts the orientation of staggered tangs  110 A,  110 B and  110 C outward projecting tangs  112 A and  112 B and triangle shaped gripper  122  on tubular shaped retainer  20  or  22 . Outward projecting tangs  112 A and  112 B are defined by U-shaped cutouts  104  and are positioned essentially 180° apart on the outer periphery of spring steel retainer  20  or  22  to provide stability when inserted into insert  18  as shown in FIG.  1 . It should be noted that tangs  112 A and  112 B have angled outward surfaces and relatively flat axial surfaces since the force that needs to be exerted on insert  18  is in direct line with the direction of insertion and removal. Tangs  112 A and  112 B allow insertion of spring steel retainers  20  and  22  into apertures  24  and  26  while restricting withdrawal of spring steel retainer  20  or  22  from insert  18 . An alternative arrangement (not shown) could include three tangs spaced even about the periphery of spring steel retainer  20  or  22  or even four tangs similarly equally spaced, providing an adequate and equal number of apertures  54  were provided in insert  18 . 
     FIG. 5 is a top view of spring steel retainer  24  or  26 . The edge  111  of staggered tangs ( 110 C depicted) that will serve to engage an inserted cable (not shown) are oriented toward forward edge  124  that is oriented as described above. By being oriented toward forward edge  124 , edges  111  of staggered cable tangs ( 110 C depicted) are able to grip and hold an armored cable (not shown) that is subsequently inserted from the direction of trailing edge  126 . Conversely, outward projecting tangs ( 112 B depicted) will be oriented with edges  113  toward trailing edge  126  thereby resisting removal of spring steel retainer  20  or  22  from aperture  54  and consequently insert  18 . An alternative embodiment might include the use of only a pair of tangs,  110 A and  110 C oriented 180° one from another with the elimination entirely of tang  110 B. While not as desirable from several standpoints, namely less restraining force against removal of an inserted cable, and less directional force guiding an inserted cable toward the center of housing  12  as described below, such an arrangement would provide an adequate structure and is clearly contemplated as within the scope of the appended claims. 
     The surfaces of tangs  110 A and  110 C have a relatively flat axial surface with tangs  110 A and  110 C angled inwardly toward the inner end of insert  18 . Tangs  112 A and  112 B and  110 A,  110 B and  110 C are lanced from the cylindrical wall of spring steel retainer  20  or  22 . The inside ends ( 111  depicted in FIG. 5) are bent in a radial direction and jagged with points since the force that needs to be exerted upon insertion of an armored cable is helical or twisting in nature and a flat surface would simply slide along the groove of such an armored cable thereby lessening the restraining force of tangs  110 A and  110 C. Tang  110 B may be flat and not bent in, so long as tangs  110 A and  110 C serve to appropriately guide the armored cable over tang  110 B so that it may contribute to the required retraining force that pushes an inserted cable toward the “untanged” wall of spring steel retainer  20  or  22  thereby providing an area between tangs  110 A,  110 B and  110 C and the interior wall of spring steel retainer  20  or  22  that is less than the diameter of the inserted cable. 
     FIG. 6 is a side view of spring steel retainer  20  or  22  of FIG. 4. A shown in this Figure, outward projecting tangs  112 A and  112 B are at staggered distances from trailing edge  126 . Two staggered cable tangs  110 B and  110 C are depicted at staggered distances from forward edge  124 . 
     FIG. 7 is a cross-sectional view of spring steel retainer  20  or  22  taken along line  7 — 7  of FIG.  4 . Staggered cable tang  110 C is depicted extending inwardly into tubular shaped spring steel retainer  20  or  22 . An angled end  115  is shown near the end of staggered cable tang  110 C. 
     FIG. 8 is an end view of spring steel retainer  20  or  24  as viewed from forward edge  124  showing staggered cable tangs  110 A,  110 B and  110 C oriented toward forward edge  124 . 
     It is important to the most successful practice of the present invention that spring steel retainers  20  and  24  be oriented within apertures  24  and  26  such that tangs  110 A,  110 B and  110 C are oriented and depicted in FIG. 1, i.e. that their orientation is such as to server to guide cable inserted therein toward the center of housing  12 . Such an orientation of spring steel cable retainers  20  and  22  simplifies the insertion of a pair of cables through hosing  12  by pre-positioning the cables toward the center of housing  12  as they are inserted thereby making the task of pushing them through cylindrical volume  40  much easier. 
     Spring steel adapter  28  includes a slot  29  to permit expansion prior to being fitted over diameter  17 , and includes a plurality of tangs  31  to prevent removal of adapter  14  from the aperture of a junction box (not shown) after installation into such an aperture. A more detailed description of adapter  14  and its operation can be found in U.S. Pat. No. 5,373,106 entitled’ “Quick Connect Fitting for Electrical Junction Box”, assigned to the same assignee as the present invention and incorporated herein by reference. 
     Peepholes  34  are provided in housing  12  to permit viewing of cable location within housing  12  during and subsequent to cable installation. 
     According to a highly preferred embodiment of the present invention, a bushing  32  comprising a cylindrical body  58  having a flange  60  at its outbound end is inserted to prevent accidental damage to inserted cable. Bushing  32  is designed to frictionally engage the interior of cylindrical outbound end  16  of housing  12  and is preferably made of a polymeric material that serves to cushion cable inserted into housing  12  and exiting therefrom through cylindrical outbound end  16 . 
     Assembly of duplex connector  10  is achieved by insertion of spring steel cable retainers  20  and  22  into apertures  24  and  26  of insert  18  such that tabs  52 A and  52 B engage openings  54 A and  54 B and their opposing counterparts (not shown) achieve similar engagement. Insert  18  is then inserted into inbound end  14  of housing  12  until fully seated. Screw  30  is then tightened into threaded hole  46  and engages surface  56  to retain insert  18  in housing  12 . Spring steel adapter  28  is then applied over flange  19  and around outer diameter  17 . 
     While duplex connector  10  can be fabricated from a variety of materials including metals and polymeric materials, it is preferred that it be fabricated as a die cast assembly with housing  12  and insert  18  both being die cast from a suitable metallic alloy. The other elements of duplex connector  10  will of course be fabricated from the materials indicated hereinabove. 
     As the invention has been described, it will be apparent to those skilled in the art that the same may be varied in many ways without departing from the spirit and scope of the invention. Any and all such modifications are intended to be included within the scope of the appended claims.

Technology Category: h