US2970287A - Fastener assembly - Google Patents

Description

Jan. 31, 1961 D. H. GILL FASTENER ASSEMBLY Filed April 24, 1959 IN VEN TOR. fla/zvZJ/k QZ/ AT TOR/V5 Y United States Pateiit 2 97 2 FASTENER ASSEMBLY Dali a Gi S -.Ijclair. S i l h-ia iti r "er'aLMotors CbrjioratidmDetroit, Micln, a corporation ofDelaware A p H Filed Apr. '24, an, as. N6. met 2 claims. 01. 339 1 1) This invention relates ,,to fastener assemblies, and more particularly to an electricallyconducting ground strap for use with a plasticnanchor.nutm. In many fastener installations in..which an electrical fixture. maynbenslecuredttoa supporting plate, little or no provisions, are made for electrically grounding the electrical fixturej with. respect to the remainder of the assembly. In. many installations.nonaconducting materials are used for the, fastenermembers, because of their relative inexpensiveness as compared to metallic fasteners; and it is easily seen thatif, a plastic fastener member is non-conducting, no grounding provisions are provided. The device-in which this invention is embodied comprises generallya staple-like strap member which may be used with a plastic, orsotherwise non-conducting, fastener member in an,,installation wherein an electrical fixture is secured to a motor vehicle supporting panel. Such an installation might be the securing of a vehicle front parking lamp to the vehicle front fender. In such an installation, the electrical fixture is secured to the supporting panel by a plastic nut member and a metallic bolt; receivable in thenut member and adapted to retain the nut member in the sup-portingpanel. In this type. of installation, no part of the metallic bolt member touches the supporting panel to provide the necessary ground connection between the electrical fixture and the supporting panel. The proposed staple-like ground strap is provided with tabs which bite into the surfaces of the electrical fixture and the supporting panel in such a manner as to provide a positive ground contact between the two parts. The device is relatively simple and inexpensive to manufacture and may be used with existing fasteners to provide suitable volume production grounding means.

In the drawings:

Figure l is a view of the fastener assembly with parts broken away and in section to illustrate the location of the various parts.

Figure 2 is a cross-sectional view of the assembly illustrated in Figure 1 taken substantially along the line 2-2 of Figure l and looking in the direction of the arrows.

Figure 3 is a cross-sectional view of the assembly shown in Figure 1 taken substantially along the line 3-3 and looking in the direction of the arrows.

Figure 4 is an isometric view of the electrical ground strap illustrated in Figure 1.

Figure 5 is a modification of the fastener assembly of Figure 1.

Figure 6 is an isometric view of the electrical ground strap used in the modification of Figure 5.

Referring more particularly to the drawings, Figures 1 through 4 illustrate a modification of the fastener assembly in which a supporting plate 10 is to receive a flange 12 of an electrical fixture, such as a vehicle parking lamp. The supporting panel 10 has, in this instance, a square aperture 14 therein to receive the fastener mem- 2,970,287 U Patented Jan. 31,1961

her. The flange 1 2 hasa cylindrical aperture 16 formed therein to receive the shank of a suitable bolt.

In properly assembling the flange 12 to the. supporting panel 10, it is necessary to have a certain amount of clearance therebetween. The nut member, illustrated generally by the numeral: 18; provides a means for receiving the fastening bolt, illustrated generally by the numeral 20, and at the same-time spaces the flange 12 from the supporting panel 10. The nut member 18 has a cylindrical head portion 22 and a prismatic shank portion 24. The prismatic shank portion extends through the square aperture 14 in the supporting panel, to prevent rotation of the nut member in the supporting-panel when the bolt is tightened. The'head portion 22 and shank portion 24- have a central bolt receiving opening 26 axially formed along the length thereof, the opening being tapered toward the end of the shank portion within that portion. I I t p l Twosides of the prismatic shank portion are provided with longitudinal triangular slots 28, allowing the two portions ofthe shank portion tospread when the bolt 20 is inserted therein. shoulder 39, formed on the split sides of the shank member, allows the shank tobe inserted inthe square aperture 14 on assembly and, when the bolt 20 is inserted therein, expand to a size greater than the square aperture 14 to prevent inadvertent removal of the fastener 18 from the supporting plate 10.

The head portion 22 of the nut member 18 has a plu: rality of axial openings 32 formed part way therethrough and circular openings 34. in the bottom of each aperture 32. extending the remainder ofthe way through the head. The apertures 32 are s eparated by a plurality of webs 36, extending between the outer rim '38 of the head member and the inner rim 40 about the-bolt receiving opening. The purpose of the apertures 32 and openings 34-will be later described. I g The bolt member 20 includes a standard head portion 42 with an annular. flange 44 extending therefrorn to form a better retaining surface for the flange 12. Extending from the head 42 and annular flange 44 is the bolt shank 46, threaded along a portion of its length, as at 48. The threads are so formed that they will cut their own corresponding thread in the shank 24 of the nut member 18, upon the usual rotation in a tightening direction. It may be seen that by tightening the bolt 20 within the head portion and shank portion of the nut member 18 that the shank 24 of the nut member will expand due to the tapered opening, to prevent the nut member from pulling away from the supporting panel 10, because of the shoulder 30. At the same time, the nut and bolt will pull the supporting panel 10 toward the flange 12, or vice versa.

In order to provide the proper ground contact between the flange 12 and the supporting panel 10, a staple-like strap member, illustrated generally by the numeral 50, is provided between the head portion 22 and the flange 12. The strap is best illustrated in Figure 4, where it is shown to have a U-shaped body portion, with a base member 52 and leg members 54 extending at right angles therefrom. A central aperture 56 receives the shank 46 of the bolt 20. A sharp pointed tab 58 is formed on the end of each leg 54, and a pair of tabs 60, also pointed, are formed from the surface of the base portion 52 in a direction away from the legs 54.

Referring again to Figure 1, it may be seen that if the strap member is secured in the assembly, the legs 54 will be received in the apertures 32 in the head portion 22 and the pointed tabs 58 extend through the holes 34 in the bottom of the apertures 32. The pointed tabs are of such length that they will bite into the surface of the supporting panel 10, upon tightening of the assembly through the bolt 20, and the pointed tabs 60 will at the same time bite into' the surface of the flange 12. Thus, a positive electrical connection is made between the supporting panel 10 and the flange 12.

A modification of the device is illustrated in Figures 5 and 6, in which the supporting panel and flange 12 are secured by the nut member 62 and the bolt 20. The nut member 62 may have a solid head portion 64, with the exception of the central bolt receiving aperture extending through the head portion 64 and the shank portion 66. The ground strap, illustrated generally by the numeral 68, is again U-shaped, having a flat base portion 70 and a pair of arcuate leg portions 72 and 74. The bolt receiving aperture 76 provides a means for retaining the ground strap, with respect to the nut and bolt assembly. In order to positively contact the supporting panel 10, the arcuate leg 72 of the strap memher is provided with a pair of points 78, formed by making an arcuate cut 80 in the leg member. A pair of tabs 82 are formed on the sides of the leg portion 72 and are adapted to bear against the head portion 64 of the nut member 62 when the assembly is made. The tabs or barbs 82 prevent the inadvertent removal of the ground strap 68 from the nut member 62. The opposite leg member 74 is formed with a single point 84 for positive contact with the support panel 10 and the barbs 82 on the leg 72 provide grip-ping contact with the head portion 64 of the nut member 62. A plurality of sharp points 86 are provided in the base surface of the ground strap to provide a positive contact with the flange 12. When the assembly is complete, the ground strap extends between the fiange 12 and the supporting panel 10, and outside of the head portion 64 of the nut member .62, to establish electrical ground contact through the sharp points 86 and the sharp points 78 and 84 which of said panels; said nut member including a shank portion receivable in an aperture in said one panel, a head portion extending radially from said shank portion and having a plurality of apertures therethrough, said head portion and said shank portion having a central bolt receiving opening therethrough; and said ground strap 2. A fastener and ground strap assembly comprising a nut member having a head portion and a shank portion, said shank portion being receivable in a first panel, a bolt member receivable in said nut member and retaining said shank portion in said panel, said bolt member being receivable in a second panel such that said second panel is secured in relative spaced relation with respect to said first panel, said head portion lying between said first and second panels when in an assembled position, and a U-shaped metallic member receivable on said bolt member and having the base portion thereof between said second panel and said nut member and positively engaging said second panel, said head portion having a plurality of apertures therethrough to receive the legs of said U-shaped member, tabs extending from the ends of the leg portions of said U-shaped member and positively engaging said first panel member to provide an electrical connection between said first and second panel members.

References (Zited in the file of this patent UNITED STATES PATENTS Elliott June 29, 1954

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