Wire-form grounding clip for electrical fixtures

Abstract

A reliable grounding path is provided between electrical fixtures and their mounting boxes with a continuous strand of wire which is configured to have upper and lower loops between which the mounting yoke of the electrical fixture is received. The loops are superposingly aligned and cooperate to create a screw receiving means therebetween for engaging the conventional mounting screw which is utilized to secure the electrical fixture within the mounting box. When the mounting screw is tightened in the screw receiving means, the upper and lower loops are forced to converge against the mounting yoke and an electrical interface thereby results between the mounting yoke and the mounting screw.

Description

BACKGROUND OF THE INVENTION

The present invention relates to grounding clips for electrical fixtures and especially such clips which are fabricated in a simplified configuration from a continuous strand of metallic wire. Hitherto, the most conventional approach to providing a grounding path between an electrical fixture and its mounting box has been to electrically connect a jumper wire therebetween upon installation of the former into the latter. This approach is very time consuming and even where sufficient time has been allotted for connecting the jumper wire, it is inadvertently disregarded on ocasion to thereby result in a hazardous condition. Therefore, many different devices have been utilized to provide the desired grounding path without encumbering the installation, however, all such devices have been of complicated designs and thereby increase ultimate costs unnecessarily.

Many metallic clips having various configurations are known by which the desired grounding path between electrical fixtures and their mounting boxes can be accomplished. One such clip is fixedly attached to the electrical fixture as disclosed in U.S. Pat. No. 3,432,793. Therefore, this clip can not be applied directly to conventional electrical fixtures and ultimate costs are increased appreciably due to the modifications necessitated thereby to the electrical fixture. Another such clip is that disclosed in U.S. Pat. No. 3,663,919 which has been assigned to the assignee of this application. This clip includes a protruding member which is forcibly wedged between the electrical fixture and the mounting box during installation. Aside from its complex configuration, this clip increases ultimate costs by sometimes causing difficulties when the electrical fixture must be removed from the mounting box at a later time. Other such clips are disclosed in U.S. Pat. No. 3,723,941 and in application Ser. No. 278,772 which was filed Aug. 8, 1972 and assigned to the same assignee as this application. Both of these clips are detachably affixable to the electrical fixture, however, they are of complicated configurations and therefore, can only be manufactured at considerable expense. Although all of the above mentioned clips are highly regarded for their intended purpose, their ultimate cost of incorporation to provide the desired grounding path is high when compared to the use of the more conventional jumper wire.

SUMMARY OF THE INVENTION

It is, therefore, a general object of the present invention to provide a grounding path between an electrical fixture and a mounting box with a detachably affixable clip which minimizes the disadvantages of the prior art.

It is another object of the present invention to provide a grounding path between an electrical fixture and a mounting box with a wire-form clip having a simplified configuration for lower manufacturing cost.

It is still another object of the present invention to provide a grounding path between an electrical fixture and a mounting box with a wire-form clip which in no way inhibits the removal of the electrical fixture from the mounting box after installation.

It is a further object of the present invention to provide a grounding path between an electrical fixture and a mounting box with a wire-form clip having portions thereof configured for retention in the conventional mounting screw slots of the electrical fixture.

It is still a further object of the present invention to provide a grounding path between an electrical fixture and a mounting box with a wire-form clip having terminations thereon to penetrate nonconductive substances on the electrical fixture.

These objects are accomplished according to the present invention by configuring a continuous strand of spring wire into an upper loop and a lower loop. Portions of each loop are cooperatively aligned to create a screw receiving means therebetween for engaging a conventional mounting screw. The gap separating the upper and lower loops is of sufficient magnitude to receive the mounting yoke of the electrical fixture against which the loops are forced to bear in making electrical contact. Depending on the particular configuration of the loops, the terminations of the continuous strand are either utilized to retain the wire-form on the electrical fixture or to penetrate nonconductive substances thereon.

BRIEF DESCRIPTION OF THE DRAWINGS

The manner in which these and other objects of the invention are achieved will be best understood by reference to the following description, the appended claims, and the Figures of the attached drawings wherein:

FIG. 1 is a partial top view of an electrical fixture mounted into a mounting box with the wire-form grounding clip of this invention incorporated therebetween;

FIG. 2 is a side view thereof with the electrical fixture being installed into the mounting box of which portions have been cut away to illustrate the electrical continuity existing between the ground terminal on the electrical fixture and the mounting yoke thereof;

FIG. 3 is a partial bottom view of the electrical fixture with the wire-form grounding clip of this invention detachably affixed thereon;

FIG. 4 is a top perspective view of the wire-form grounding clip;

FIG. 5 is a bottom perspective view thereof;

FIG. 6 is a top perspective view of another wire-form clip having an alternate configuration in accordance with this invention;

FIG. 7 is a bottom view thereof;

FIG. 8 is a side view thereof including a mounting yoke portion of the electrical fixture in section to illustrate the initial step in detachably affixing the clip to the mounting yoke, with a more advanced step shown in phantom;

FIG. 9 is a view similar to that of FIG. 8 but illustrating the final orientation of the clip on the mounting yoke with a mounting screw disposed through the screw receiving means;

FIG. 10 is a view similar to that of FIG. 9 but illustrating the converged position of the loops against the mounting yoke when the mounting screw is tightened into the screw receiving means;

FIG. 11 is a top perspective view of still another wire-form clip having an alternate configuration in accordance with this invention; and

FIG. 12 is a top view thereof after being detachably affixed on the mounting yoke of the electrical fixture, with the mounting screw shown sectionally within the screw receiving means which is created by the cooperative arrangement of the upper and lower loops.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Turning now to the drawings and more particularly to FIGS. 1, 2 and 3 there is illustrated an electrical fixture 10 which is secured into a mounting box 12 with a wire-form grounding clip 14 disposed therebetween in accordance with this invention. Any suitable electrical fixture 10 could be secured into the mounting box 12 but, by way of example, a standard duplex receptacle outlet 16 has been chosen for use in this disclosure. To eliminate the safety hazard which would otherwise exist, the wire-form grounding clip 14 provides for the electrical continuity necessary to achieve a grounding path between the outlet 16 and the mounting box 12.

In general configuration, the mounting box 12 is an open-ended enclosure having rectangular sides. The mounting box 12 is fabricated of conductive metal and must be electrically grounded by suitable means. A mounting flange 18 is provided on the mounting box 12 and has threaded apertures 20 which engage with mounting screws 22 in securing the outlet 16 to the mounting box 12.

The outlet 16 has a generally compatible configuration to that of the mounting box 12 and includes a body 24 made of suitable insulating material, such as plastic. At the front of the body 24, identical but separate grounded receptacles 26 are disposed. Each receptacle 26 includes a pair of spaced slots 28 associated with internal female contacts (not shown) and a semi-circular opening 30 associated with an internal female grounding contact (not shown). The female contacts mate with the male contacts of a plug and the female grounding contact mates with the male grounding contact on the plug. Screws 32 comprise suitable terminal means for connecting wire conductors to the female contacts and thereby provide for electrically energizing the receptacles 26. A metallic mounting yoke 34 extends across the rear of the body 24 and is affixed thereto by any suitable means, such as folding tabs 36. The mounting yoke 34 is also configured to extend along both sides of the body 24 and project laterally therefrom at each side thereof to form mounting ears 38. An elongated slot 40 is disposed through each mounting ear 38 to permit passage of the mounting screw 22 in alignment with the threaded aperture 20 of the mounting box 12. A grounding screw 42 comprises suitable terminal means for connecting a ground wire to the mounting yoke 34 which in turn is electrically connected by suitable means (not shown) to the female grounding contacts within the receptacles 26.

The wire-form grounding clip 14 is fabricated from a continuous strand of electrically conductive wire in a configuration which includes an upper loop 44 and a lower loop 46, as illustrated in FIGS. 4 and 5. The loops 44 and 46 are separated by a gap 48 and are superposingly aligned to cooperate in creating a screw receiving means 50 therebetween for engaging with the threads on the mounting screw 22. The gap 48 is of sufficient magnitude to permit the thickness of the mounting yoke 34 to fit thereinto.

In use, the clip 14 is disposed on the mounting yoke 34 with the lower and upper loops 44 and 46 separated across one mounting ear 38 thereof and with the screw receiving means 50 aligned through the slot 40 in the mounting ear 38. Then the mounting screw 22 is disposed through the screw receiving means 50 to detachably affix the grounding clip 14 and when the mounting screw 22 is tightened, the upper and lower loops 44 and 46 are forced to converge and bear against the mounting ear 38. Therefore, a very reliable electrically conductive path between the mounting yoke 34 and the mounting screw 22 is established through the clip 14. This is so because the grounding clip 14 is electrically conductive and the screw receiving means 50 thereon makes electrical contact with the mounting screw 22, while the loops 44 and 46 thereof make electrical contact with the mounting yoke 34. Of course, the gap 48 could be lesser magnitude than the thickness of the mounting yoke 34 and then the clip 14 would be detachably affixable on the mounting ear 38 without the mounting screw 22, in that the upper and lower loops 44 and 46 would continually bear forcibly thereagainst.

Although the structure described above is essential to the concept of this invention, many different wire-form clip configurations are possible, some of which provide auxiliary features. In fact, grounding clip 14 has a more particular configuration in that the upper loop 44 is configured to provide clearance for the threads on the mounting screw 22, while the screw receiving means 50 is disposed solely on the lower loop 46. More precisely the upper loop 44 includes a first bend 52 of substantially 180.degree. and has members 54 which extend from each side of the first bend 52 to a second bend 56 of substantially 180.degree.. The lower loop 46 includes symmetrical members 58, each of which extends from one of the second bends 56 to a third bend 60 of substantially 180 degrees. A spring member 62 extends beyond the third bend 60 to a point of termination on each symmetrical member 58 and the symmetrical members 58 are cooperatively arranged in the lower loop 46 with the spring members 62 cooperating to create the screw receiving means 50 therebetween.

Although not essential to the primary function of the grounding clip 14, each spring member 62 is terminated with an inclined tip 64 which locates in the slot 40 of the mounting yoke 34, as illustrated in FIG. 3. Furthermore, to dispose the first bend 52 in a reference plane with each second bend 56 in a plane perpendicular to the reference plane and both third bends in a plane parallel to the reference plane, as illustrated in FIGS. 4 and 5, is the preferred configuration. However, such precise orientation and configuration of the loops 44 and 46 is not essential to the concept of this invention, as will be discussed later. Also it is preferable to use as material for the grounding clip 14, wire having a diameter which can be disposed between the threads of the mounting screw 22.

Generally, the grounding clip 14 with the precise configuration of FIGS. 4 and 5 is detachably affixable to the mounting yoke 34 of the electrical fixture 10 in the same manner described previously. Of course, when the inclined tips 64 are included, the grounding clip 14 must be manipulated to locate them in the slot 40 to thereby retain the clip 14 on the mounting ear 38 even when the mounting screw 22 is not disposed through the screw receiving means 50. Furthermore, the spring members 62 are interspaced at a distance to create the screw receiving means 50, as illustrated in FIG. 3. If necessary, the spring members 62 are deflectable and the distance therebetween is dependent on the contact pressure desired against the mounting screw 22 and the wire diameter utilized. Therefore, the screw receiving means 50 continually bears against the threads of the mounting screw 22 with a force proportional to the spring constant of the spring members 62. Furthermore, the clip 14 and the mounting screw 22 can be detachably affixed on the electrical fixture 10 during shipment or storage thereof, in a condition for immediate installation. Normally a cardboard washer is used to retain the mounting screw 22 during such shipment and storage periods but because of the force exerted thereagainst by the screw receiving means 50, no such washers are necessary.

After the grounding clip 14 has been detachably affixed on the electrical fixture 10 with the mounting screw 22 disposed through the screw receiving means 50, direct installation into the mounting box 12 is then possible by merely aligning the mounting screws 22 with the threaded apertures 20 thereof. It should be noted that the cardboard washers used in the past, as mentioned above, had to be removed before installation of the electrical fixture 10. Of course, this increased installation time and was necessary because electrical continuity between the mounting box 12 and the mounting yoke 34 could be precluded, if such washers were not removed. Furthermore, the corrective action necessary in those installations where such washers have not been removed due to inadvertence is very time consuming.

As described previously, a very reliable grounding path is established between the mounting yoke 34 and the mounting screw 22 by the grounding clip 14. When the electrical fixture 10 is installed in the mounting box 12, forcible retention therebetween is provided through the mounting screw 22 which engages with the threaded aperture 20. Therefore, the grounding path is then extended from the electrical fixture 10 to the mounting box 12 through the grounding clip 14.

Another preferred embodiment of the grounding clip 14' is illustrated in FIGS. 6 and 7, where similar parts to those illustrated in FIGS. 1 - 5 are identified with the same reference numerals but with a prime (') added. The grounding clip 14' again includes an upper loop 44' and a lower loop 46' which are separated by a gap 48'. However, the continuous strand of metallic wire is configured quite differently in forming the loops 44' and 46'. The lower loop 44' includes a bend 66 of substantially 180.degree. and has spring members 68 which extend from each side of bend 66 to a bend 70 through an obtuse angle. As previously described for grounding clip 14, the spring members 68 are cooperatively disposed in the lower loop 46' to create a screw receiving means 50' therebetween. The upper loop 44' includes symmetrical members 72, each of which extends in a continuous path from one obtuse angled bend 70 to a first bend 74 through an acute angle in the direction of the lower loop 46', from the first acute angled bend 74 to a second bend 76 through an acute angle away from the lower loop 46' , and from second acute angled bend 76 to a point of termination.

In use the grounding clip 14' establishes a very reliable grounding path between the mounting yoke 34 and the mounting screw 22 as described previously for grounding clip 14. However, as illustrated in FIGS. 8 - 10, grounding clip 14' is detachably affixable to the mounting yoke 34 in a different manner than is grounding clip 14. As shown in FIG. 8, the symmetrical members 72 are first directed through the slot 40 in the mounting yoke 34 and then the grounding clip 14' is manipulated to separate the loops 44' and 46' across the thickness of the mounting ear 38, as illustrated in phantom. The mounting screw 22 is then inserted into the screw receiving means 50', as illustrated in FIG. 9. Of course, when the mounting screw 22 is tightened, the loops 44' and 46' are forced to converge and bear against the mounting ear 38 with the lower loop 46' interfittingly disposed between the symmetrical members 72, as illustrated in FIG. 10. With the loops 44' and 46' forcibly converged, it should be realized that the termination on each symmetrical member 72 is forced against the mounting ear 38 with great pressure so that nonconductive substances thereon are penetrated to decrease the electrical contact resistance.

Although it is essential that the lower loop 46' interfit between the symmetrical members 72, many different wire-form clip configurations are possible to accomplish this interfit. In these various configurations, the spring members 68 and the symmetrical members 72 can be disposed convergently, divergently, or in parallel on their respective loops 44' and 46'. However, the preferred embodiment is illustrated in FIG. 7 where the spring members 68 are disposed in parallel, while the symmetrical members 72 are divergently disposed.

Still another preferred embodiment of a grounding clip 14" is illustrated in FIGS. 11 and 12 where similar parts to those of FIGS. 1 - 5 are identified by the same reference numerals, but with a double (") added. The grounding clip 14" again includes an upper loop 44" and a lower loop 46" which are interconnected across a gap 48" by a bend 78 of substantially 180.degree.. Each loop 44" or 46" has a spring member 80 extending from the bend 78 to a bend 82 through an obtuse angle. The obtuse angled bends 82 are disposed in substantially parallel planes and the spring members 80 are cooperatively arranged to create a screw receiving means 50" therebetween. Because of its simplistic nature, the configuration of grounding clip 14" can have many variations within the inventive concept. Of course, the obtuse angled bends 82 could be in either the same or opposite directions and could actually be bends of 180.degree.. Furthermore, it is not essential that the obtuse angled bends 82 be disposed in parallel planes and the spring members 80 could be disposed convergently, divergently, or in parallel relative to each other.

Generally, the grounding clip 14" is detachably affixable to the electrical fixture 10 in the same manner previously described for gounding clip 14 and establishes a reliable grounding path between the mounting yoke 34 and the screw 22. Of course, the mounting screw 22 is received between the spring members 80 and retains the grounding clip 14" on the electrical fixture 10, as illustrated in FIG. 12. However, the gap 48" could be of lesser magnitude than the thickness of the mounting yoke 34 and cause the upper and lower loops 44" and 46" to bear forcibly thereagainst in retaining the grounding clip 14" on the electrical fixture 10 without using the mounting screw 22.

It should be readily appreciated by those skilled in the art that the wire-form grounding clip embodied by this invention is of a simplified configuration and may be detachably affixed on an electrical fixture to provide a very reliable grounding path with a mounting box through a mounting screw. Also, the wire-form configuration can be adapted to exert continual contact pressure against the mounting yoke of the electrical fixture or attain such contact pressure after the mounting screw has been tightened into screw receiving means of the grounding clip. Furthermore, the terminations of the wire-form configuration can be oriented to either lock the grounding clip on the electrical fixture or to penetrate nonconductive substances thereon in decreasing electrical contact resistance.

It should be understood that the present disclosure has been made only by way of example and that numerous changes in details of construction and the combination or arrangement of parts may be resorted to without departing from the true spirit and scope of the invention. Therefore, the present disclosure should be construed as illustrative rather than limiting.

Claims

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 into a mounting box with mounting screws through slots in the mounting yoke, said grounding clip comprising:

a continuous strand of spring wire, said strand being formed into an upper loop and a lower loop, said upper and lower loops being separated by a gap and being superposingly aligned with said upper loop being configured to provide clearance for threads on the mounting screw and said lower loop being configured to include a screw receiving means for engaging the mounting screw, said upper loop including a first bend of substantially 180.degree. with members extending from each side thereof to a second bend of substantially 180.degree., said lower loop including symmetrical members with each said symmetrical member extending from one of said second bends to a third bend of substantially 180.degree. and having a spring member extending from said third bend to a point of termination, said symmetrical members being arranged in said lower loop with said spring members cooperating to create said screw receiving means therebetween, each said spring member being terminated with an inclined tip, said inclined tips being disposed to locate in the slot of the mounting yoke and thereby retain said grounding clip on the electrical fixture, said grounding clip being detachably affixable on the electrical fixture with the mounting yoke thereof disposed in said gap and said screw receiving means aligned through one of the slots in the mounting yoke, said upper and lower loops being forcibly convergent aganist the mounting yoke to bear thereagainst when the mounting screw is tightened in said screw receiving means. affixingly engaging in one

2. In combination, a grounding clip and an electrical fixture; said electrical fixture being of the type having a grounded mounting yoke with mounting slots formed therein whereby the fixture is arranged to be secured in a mounting box by mounting screws which extend through said slots; and said ground clip comprising a continuous strand of spring wire having end terminations, said strand being formed into an upper loop and a lower loop, said upper and lower loops being separated by a gap and being superposingly aligned to create a screw receiving means therebetween for engaging a mounting screw, said terminations affixingly in none mounting yoke slot when said grounding clip is disposed on the electrical fixture with the mounting yoke thereof disposed in said gap and said screw receiving means aligned through the slot, said upper and lower loops being forced to converge against the mounting yoke thereafter when the mounting screw is tightened in said screw receiving means.

3. The combination of claim 2 wherein said gap is of lesser magnitude than the thickness of the mounting yoke, said grounding clip being detachably affixable on the mounting yoke with said upper and lower loops continually bearing forcibly thereagainst to establish electrical continuity between said grounding clip and the electrical fixture.

4. The combination of claim 2 wherein said upper loop is configured to provide clearance for threads on the mounting screw and said lower loop is configured to include said screw receiving means.

5. The combination of claim 4 wherein said upper loop includes a first bend of substantially 180.degree. with members extending from each side thereof to a second bend of substantially 180.degree., and said lower loop includes symmetrical members with each said symmetrical member extending from one of said second bends to a third bend of substantially 180.degree. and having a spring member extending from said third bend to a point of termination, said symmetrical members being arranged in said lower loop with said spring members cooperating to create said screw receiving means therebetween.

6. The combination of claim 5 wherein said gap is of lesser magnitude than the thickness of the mounting yoke, said grounding clip being detachably affixable on the mounting yoke with said upper and lower loops continually bearing forcibly thereagainst to establish electrical continuity between said grounding clip and the electrical fixture.

7. The combination of claim 4 wherein said lower loop includes a bend of substantially 180.degree. with spring members extending from each side thereof to separate bends through equal obtuse angles, said spring members being cooperatively arranged in said lower loop to create said screw receiving means therebetween; and said upper loop includes symmetrical members with each said symmetrical member extending in a continuous path from one of said obtuse angled bends to a first bend through an acute angle in the direction of said lower loop, from said first acute angled bend to a second bend through an acute angle away from said lower loop, and from said second acute angled bend to a point of termination; said grounding clip being detachably affixable on the electrical fixture with said symmetrical members extending through the slot in the mounting yoke to bear against the underside thereof and said lower loop interfitting between said symmetrical members when the mounting screw is tightened in said screw receiving means.

8. The combination of claim 2 wherein said loops are interconnected across said gap by a first bend of substantially 180 degrees, each said loop being a spring member which extends from said first bend to a bend through an obtuse angle at one termination of said strand, said spring members being cooperatively arranged to create said screw receiving means therebetween.

9. The combination of claim 8 wherein said gap is of lesser magnitude than the thickness of the mounting yoke, said grounding clip being detachably affixable on the mounting yoke with said upper and lower loops continually bearing forcibly thereagainst to establish electrical continuity between said grounding clip and the electrical fixture.

10. A grounding clip for use with an electrical fixture of the type having a grounded mounting yoke by which the fixture is secured into a mounting box with mounting screws through slots in the mounting yoke, said grounding clip comprising:

a continuous strand of spring wire, said strand being formed into an upper loop and a lower loop, said upper loop including a first bend of 180.degree. in a first plane and having members extending from each side of said first bend to a second bend of 180.degree. in a second plane perpendicular to said first plane, said lower loop including symmetrical members, each said symmetrical member extending from one of said second bends to a third bend of 180.degree. in a third plane parallel to said first plane and having a spring member extending from said third bend to a point of termination, said symmetrical members being arranged in said lower loop with said spring members cooperating to create said screw receiving means therebetween, said upper and lower loops being separated by a gap and being superposingly aligned to pass the mounting screw through said screw receiving means, said grounding clip being detachably affixable on the electrical fixture with the mounting yoke thereof disposed in said gap and said screw receiving means aligned through one of the slots in the mounting yoke, said upper and lower loops being forcibly convergent against the mounting yoke to bear thereagainst when the mounting screw is tightened in said screw receiving means.

11. The grounding clip of claim 10 wherein said gap is of lesser than the thickness of the mounting yoke, said groundiing clip being detachably affixable on the mounting yoke with upper and lower loops continually bearing forcibly thereagainst to establish electrical continuity between said grounding clip and the electrical fixture.

12. The grounding clip of claim 10 wherein each said spring member is terminated with an inclined tip, said inclined tips being disposed to locate in the slot of the mounting yoke and thereby retain said grounding clip on the electrical fixture.