Grounding clip for electrical fixtures

Abstract

Apparatus for providing a reliable grounding path between electrical fixtures and their mounting boxes, particularly where modifications to the conventional nature of the electrical fixtures are unnecessary. A metal clip is disposed as a conductive interface between the mounting yoke of the electrical fixture and the mounting screw utilized to secure the electrical fixture within the mounting box. Low resistance electrical contacts are maintained by disposing spring members on the clip to exert continual contact pressure against both the mounting yoke and the mounting screw. Sharp protrusions extend from the clip to concentrate the contact pressure exerted against the mounting yoke and the mounting screw is engaged by a screw-receiving means on the clip. A spring means is disposed within the screw receiving means to develop the contact pressure and also provides for self-adjustabliity to pitch variations of the mounting screws or to fixed pitch references of the mounting box.

What I claim is: 
     
       1. A grounding clip for use with an electrical fixture of the type having a grounded mounting yoke by which the fixture is secured to a mounting box with mounting screws extending through slots in the mounting yoke, said grounding clip .[.comprising:.]. .Iadd.consisting of .Iaddend.a U-shaped spring having a first member and a second member, said members being substantially flat planar members, said members being separated by a gap of lesser magnitude than the thickness of the mounting yoke, said first member including an aperture, said second member including screw-receiving means aligned with said aperture for engaging a mounting screw, said screw-receiving means including a pair of cantilever arms, said grounding clip being mountable on the mounting yoke of the electrical fixture with said members forcibly bearing against the mounting yoke to establish electrical continuity therebetween and with said aperture and said screw-receiving means aligned with one of the mounting yoke slots to receive a mounting screw, said cantilever arms being deflectable .Iadd.and having ends which, in plan, follow straight-line paths at least in the regions where they contact the threads of the mounting screw .Iaddend.to slide over and forcibly abut against the threads of the mounting screw in maintaining electrical continuity therebetween as the mounting screw is axially engaged into said screw-receiving means. 
     
     
       2. The grounding clip of claim 1 wherein .Iadd.at a location spaced from said aperture .Iaddend.protrusions extend .[.into said gap.]. from one of said members .Iadd.toward the other to define said gap between the ends of said protrusions and the opposing surface of said other member.Iaddend., said protrusions being effective to concentrate the contact pressure exerted against the mounting yoke and thereby decrease the electrical contact resistance therebetween. 
     
     
       3. The grounding clip of claim 1 wherein rolled tips are disposed on said screw-receiving means, said rolled tips being configured to engage .[.between.]. threads on the mounting screw and effectuate the electrical continuity. 
     
     
       4. The grounding clip of claim 1 wherein diverging terminations are disposed on said members, said terminations being effective to facilitate the disposition of said grounding clip on the mounting yoke. 
     
     
       5. The grounding clip of claim 1 wherein protrusions extend .[.into said gap.]. from one of said members .Iadd.toward the other to define said gap between the ends of said protrusions and the opposing surface of said other member.Iaddend., said protrusions being effective to concentrate the contact pressure exerted against the mounting yoke and thereby decrease the electrical contact resistance therebetween; rolled tips are disposed on said screw-receiving means, said rolled tips being configured to engage .[.between.]. threads on the mounting screw and effectuate the electrical coontinuity; diverging terminations are disposed on said members, said terminations being effective to facilitate the disposition of said grounding clip on the mounting yoke. 
     
     
       6. In an electrical fixture of the type adapted to be mounted in an electrically grounded metal mounting box, wherein a metallic mounting yoke supports an insulated body and is connected to a grounding contact within said body, said mounting yoke having at least one mounting ear extending therefrom, said mounting ear containing a slot to receive a mounting screw therethrough in securing said electrical fixture into the mounting box, the improvement comprising: a grounding clip detachably affixed to said mounting ear, said grounding clip .[.being.]. .Iadd.consisting of .Iaddend.a U-shaped spring, said spring having a first member and a second member, said members being substantially flat planar members, said members being separated by a gap of lesser magnitude than the thickness of said mounting ear, said first member including an aperture, said second member including screw-receiving spring means aligned with said aperture for engaging the mounting screw, said grounding clip being detachably retained on said mounting ear with said members forcibly bearing thereagainst to establish electrical continuity therebetween and with said aperture and said screw-receiving means aligned with said slot, said screw-receiving spring means being deflectable .Iadd.and having ends which, in plan, follow straight-line paths at least in the regions where they contact the threads of the mounting screw .Iaddend.to slide over and forcibly abut against the threads of the mounting screw in maintaining electrical continuity therebetween as the mounting screw is axially engaged thereinto.   
     
     
       7. The combination of claim 6 wherein said screw-receiving spring means includes a pair of cantilever arms. 
     
     
       8. The combination of claim 7 wherein .Iadd.at a location spaced from said aperture .Iaddend.protrusions extend .[.into said gap.]. from one of said members .Iadd.toward the other to define said gap between the ends of said protrusions and the opposing surface of said other member.Iaddend., said protrusions being effective to concentrate the contact pressure exerted against said mounting yoke and thereby decrease the electrical contact resistance therebetween. 
     
     
       9. The combination of claim 7 wherein rolled tips are disposed on said cantilever arms, said rolled tips being configured to engage .[.between.]. threads on the mounting screw and effectuate the electrical continuity. 
     
     
       10. The combination of claim 7 wherein diverging terminations are disposed on said members, said terminations being effective to facilitate the disposition of said grounding clip on said mounting yoke. 
     
     
       11. The combination of claim 7 wherein protrusions extend .[.into said gap.]. from one of said members .Iadd.toward the other to define said gap between the ends of said protrusions and the opposing surface of said other member.Iaddend., said protrusions being effective to concentrate the contact pressure exerted against said mounting yoke and thereby decrease the electrical contact resistance therebetween; rolled tips are disposed on said cantilever arms, said rolled tips being configured to engage .[.between.]. threads on the mounting screw and effectuate the electrical continuity; and diverging terminations are disposed on said members, said terminations being effective to facilitate the disposition of said grounding clip on said mounting yoke. .Iadd. 12. A detachable grounding clip for use with an electrical device of the type employing a conductive mounting yoke for securing the device to a mounting box by means of mounting screws having threads which follow a predetermined helical path extending through open areas in the mounting yoke, said grounding clip consisting of a U-shaped conductive member having first and second substantially flat planar side members joined together at one end to form the U-shape, said first side member including an aperture therethrough, said second side member including an apertured screw-receiving means integral therewith and aligned with the aperture in said first side member, said screw-receiving means including a plurality of arms extending toward one another to provide opposed free edges with an aperture therebetween for engaging threaded portions of a mounting screw passing through the apertures in said first and second members, said grounding clip being detachably mountable on the mounting yoke with the apertures therethrough aligned with one of the open areas of the mounting yoke to receive a mounting screw, at least one of said arms being cantilevered and deflectable to facilitate insertion of the mounting screw and engagement and electrical continuity with its threads, said arms having ends which follow paths substantially different from the predetermined path of the threads of the mounting screw to facilitate sliding over said threads, the spacing between the closest points of any portions of said opposing side members, before being mounted on the yoke, being less than the thickness of the yoke, whereby when the clip is inserted on the yoke it bears forcibly against opposite surfaces of the yoke to maintain electrical continuity between the screw-receiving means and the yoke. .Iaddend. .Iadd. 13. A detachable grounding clip as defined in claim 12 wherein the opposed free edges of said arms are substantially parallel to one another. .Iaddend..Iadd. 14. A detachable grounding clip for use with an electrical device of the type employing a conductive mounting yoke for securing the device to a mounting box by means of mounting screws extending through apertured areas in the mounting yoke, said grounding clip comprising a U-shaped conductive member having first and second substantially flat planar side members joined together at one end to form the U-shape, said first side member including an aperture therethrough, said second side member having an aperture aligned with the aperture in said first side member, the aperture through said second side member having two opposing and substantially parallel edges for receiving and contacting and sliding over the threads of a mounting screw passing through the aperture in the first member, at least one of said edges being deflectable by the mounting screw to facilitate receiving and engaging the threaded portion thereof, said grounding clip being detachably mountable on the mounting yoke with the apertures therethrough aligned with one of the apertures of the mounting yoke to receive the mounting screw, said parallel edges facilitating insertion of the mounting screw and maintaining electrical continuity with its threads, at least one protuberance formed on at least one of said side members and projecting toward the other side member, the spacing between the protuberance and the closest surface of the opposing side member, before being mounted on the yoke, being less than the thickness of the yoke, whereby when the clip is inserted on the yoke electrical continuity is established between the clip and the yoke at least by way of said protuberance. .Iaddend..Iadd. 15. A detachable grounding clip as defined in claim 14 wherein the parallel opposite edges defining the aperture through the second side member constitute the only surfaces of said clip which contact the threaded portion of the mounting screw. .Iaddend..Iadd. 16. A detachable grounding clip for use with an electrical device of the type employing a conductive mounting yoke for securing the device to a mounting box with mounting screws extending through open areas in the mounting yoke, said grounding clip comprising a U-shaped spring having a first member and a second member, the members being substantially flat planar members separated by a gap and at least one of said members having an outwardly diverging end for facilitating initial insertion of the clip on the yoke, said first member including an aperture, said second member including screw-receiving means integral therewith and having an aperture aligned with the aperture in said first member, said screw-receiving means including a plurality of integral arms extending toward one another to form the aperture in said second member, said arms providing substantially parallel, opposed, spaced-apart free ends for engaging and sliding over threaded portions of a mounting screw, said grounding clip being detachably mountable on the mounting yoke with the apertures in the first and second members aligned with one of the openings in the mounting yoke to receive the mounting screw, the free ends of said arms being rolled and at least one being deflectable to facilitate sliding engagement with the threads of the mounting screw and to maintain electrical continuity therebetween when the mounting screw is engaged by said screw-receiving means, a plurality of protuberances projecting from at least one of said members toward the other, said protuberances located adjacent the area where at least one of said members diverges and having inclined surfaces to facilitate the insertion of the clip on the yoke, the spacing between the innermost ends of said protuberances and the closest surface of the opposing member being less than the thickness of the mounting yoke before the clip is mounted thereon, whereby when the clip is yieldably inserted on the yoke electrical continuity is established between the screw-receiving means and the yoke at least by way of said protuberances. .Iaddend. .Iadd. 17. A detachable grounding clip for use with an electrical device having a conductive mounting yoke for securing the device to a conductive mounting box by means of conductive mounting screws extending through slots in the yoke, said grounding clip consisting of a U-shaped conductive member having first and second substantially planar side members joined together at one end to form a U-shape, said first side member including an aperture therethrough, said second side member including screw receiving and supporting means integral therewith and having an aperture aligned with the aperture in said first side member, said screw receiving and supporting means including a pair of integral arms having cooperating and opposing surfaces forming the aperture in said second side member, said opposing surfaces lying along a non-helical path and being shaped complementary to one another and dimensioned to receive and make sliding contact with a mounting screw passing through the aperture in the first side member, and being deflectable by said mounting screw to facilitate receiving and slidingly engaging the threaded portion thereof, said grounding clip being detachably mountable on the mounting yoke with said apertures therethrough aligned with one of the slots of the mounting yoke to receive the mounting screw, said arms maintaining electrical continuity with said mounting screw, the spacing between the closest points of said opposing side members, before the clip is mounted on the yoke, being less than the thickness of the yoke, whereby said side members maintain pressing contact with the opposite surfaces of the yoke. .Iaddend..Iadd. 18. A grounding clip as in claim 17 wherein at least one of said side members is flared at the open end of the U-shape to facilitate mounting on the yoke. .Iaddend..Iadd. 19. A detachable grounding clip for use with an electrical device having a conductive mounting yoke for securing the device to a conductive mounting box by means of conductive mounting screws extending through slots in the yoke, said grounding clip consisting of a U-shaped conductive member having first and second side members joined together at one end to form a U-shape, said first side member including an open area therein, said second side member including screw receiving and supporting means integral therewith and having an aperture aligned with the open area in said first side member, said screw receiving and supporting means including a pair of substantially coplanar arms having cooperating opposing surfaces lying along a non-helical path and forming the aperture in said second side member, the aperture in the second side member being smaller than the open area in the first side member and smaller than the shank of the mounting screws to be received, at least one of said arms being deflectable by the mounting screw to receive the screw in sliding engagement and maintain a pressing contact with said screw, said grounding clip being detachably mountable on the mounting yoke with the aperture in the second side member aligned with one of the slots of the mounting yoke to receive the mounting screw, the spacing between the closest points of said opposing side members, before the clip is mounted on the yoke, being less than the thickness of the yoke, whereby said side members span the yoke in pressing contact with the opposite surfaces thereof. .Iaddend.