US3564483A - Signal lamp with built-in ground strap - Google Patents

Abstract

THE HOUSING OF A SIGNAL LAMP IS FABRICATED OF AN ELECTRICAL INSULATOR, AND A THREADED STEM DEPENDS FROM THE HOUSING FOR MOUNTING THE LAMP ON A SUPPORT, A GROUND STRAP IS ELECTRICALLY CONNECTED TO ONE OF THE CONTACTS OF A BULB SOCKET IN THE HOUSING AND HAS A PART THEREOF POSITIONED IN AN OPEN CHANNEL IN THE STEM SUCH THAT THIS PART IS CONTACTED BY AN ELECTRICALLY CONDUCTIVE NUT ADAPTED TO BE THREADED ON THE STEM WHEN MOUNTING THE LAMP IN POSITION.

Description

Feb. 16, 1971 v H. MAG! 3,564,483

SIGNAL LAMP WITHQfBUILT-IN GROUND S'I'RAP Filed March 21, 1969 33 INVENTOR.

Attorney 7 United States Patent 3,564,483 SIGNAL LAMP WITH BUILT-IN GROUND STRAP Hugo Magi, Etobicoke, Ontario, Canada, assignor to Dominion Auto Accessories Limited, Toronto, Ontario, Canada Filed Mar. 21, 1969, Ser. No. 809,315 Int. Cl. H01r 13/32 US. Cl. 339-130 7 Claims ABSTRACT OF THE DISCLOSURE The housing of a signal lamp is fabricated of an electrical insulator, and a threaded stem depends from the housing for mounting the lamp on a support. A ground strap is electrically connected to one of the contacts of a bulb socket in the housing and has a part thereof positioned in an open channel in the stem such that this part is contacted by an electrically conductive nut adapted to be threaded on the stem when mounting the lamp in position.

This invention relates generally to lamps, and, more particularly, to signal lamps, such as direction signal lamps, for motor vehicles.

The grounding of a lamp having a hOusing fabricated of an electrically conductive material generally does not pose much of a problem, since the housing itself can serve as a vehicle for grounding the lamp. This cannot be done, however, when the housing is fabricated of an electrically insulating material such as plastic, for example, and it has been common practise in such cases to provide a grounding wire that is brought out of the lamp and grounded in some way.

In accordance with the instant invention there is provided a lamp that has a permanent ground strap so ranged that securing of the lamp to a grounded support automatically will ground the lamp.

This invention will become more apparent from the following detailed disclosure, taken in conjunction with the appended drawings, in which:

FIG. 1 is a perspective exploded view f part Of a direction signal lamp embodying the instant invention; and

FIG. 2 is a front elevation, partly broken away and partly in section, showing how a lamp embodying the instant invention is mounted.

Referring to the drawings, a direction signal lamp includes a housing 10 made of electrically insulating material, e.g., a suitable plastic, to which is fastened by any suitable means lenses 11. Only one lens 11 is shown, but it will be understood that an identical lens will project forwardly from the front of housing 10 being mounted on the rim 12 thereof. Lenses 11 are transparent or translucent and may be coloured or plain. Generally one lens will be red and the other amber for a direction signal lamp. Lenses 11 may have semicircular flanges thereon that snap into mating grooves in rims 12, or O-rings may be employed between lenses 11 and rims 12.

Projecting inwardly from rim 12 but formed integral therewith and constituting a part of housing 10 is a strengthening partition 13 in which is provided a recess 14 that is occupied by the light bulb (not shown) of the lamp.

Located below recess 14 and held in position by shock absorbing and vibration dampening supports 15 that are described and claimed in copending patent application Ser. No. 32,084, filed Apr. 27, 1970 for Shock Resistant Mountings for Light Bulbs and which are formed integral with partition 13 is a light bulb socket 16. Part 16a of socket 16 is formed integral with the supports 15 and thus "ice is fabricated of plastic, if this is the material used for housing 10. The other part 16b of socket 16 constitutes one contact for one terminal of the light bulb of the lamp and is made of metal. As may be seen by reference to the drawings, socket 16 is of the bayonet type, but obviously could be of the type to receive a screw-in bulb. The other contact 17 of socket 16 is conventional being an electrical contact disposed in or on a disc 18 of electrically insulating material that is biased upwardly by a spring 19.

Formed integral with housing 10 and depending downwardly therefrom is a hollow, threaded stem or stud 20. Stud 20 has an open channel 21 formed therein. Located in channel 21 is a metal ground strap 22 that is electrically connected to socket part 16b and the other end of which is hooked over the end of stud 20.

In the manufacture of the lamp shown in the drawings, the hooked end of ground strap 22 is inserted through an opening 23 in housing 10 that registers with channel 21, strap 22 is positioned in the channel, and the hooked end of the ground strap is hooked over the end of stud 20. The rectangular end portion 24 of ground stra 22 then is positioned in a recess 25 formed for it in socket part 16a with the stud 26 extending through the opening 27 formed in end portion 24, stud 26 being formed integral with socket part 16a. Socket part 16b then is mounted on socket part 16a with the studs 26 and 28 of socket part 1611 projecting through openings 29 and 30 formed in cars 31 and 32 of socket part 16b. After this has been done, socket part 16b and ground strap 22 are physically secured together and positively electrically connected, as by ultrasonic welding. When this has been accomplished, studs 26 and 28 are melted over cars 31 and 32 to form caps that hold socket part 16b in place. Of course, during the assembly of socket 16, spring 19, contact 17 and disc 18 are located within the socket and the insulated conductor 33 that is soldered or otherwise connected to contact 17 is passed through opening 34 in housing 10 and brought out of the lamp via hollow stem 20.

As best shown in FIG. 2, the depth of channel 21 preferably is such that the two edges 35 and 36 (FIG. 1) of ground strap 22 extend above the roots of the threads on stem 20. This ensures positive grounding of the lamp. In this regard, as best seen in FIG. 2, reference numeral 37 designates a grounded part, say the fender, of a motor vehicle. In mounting the lamp on the fender, stem 20 is inserted through an opening in the fender, an electrically conductive washer 38 is placed over stem 20 and an electrically conductive nut 39 is screwed into stem 20 and tightened. The threads on nut 39 will bite into edges 35 and 36 of ground strap 22 and, when the nut has been tightened, grounding of the lamp will be effected automatically via ground strap 22, nut 39, washer 38 and fender 37.

What I claim as my invention is:

1. A signal lamp comprising a housing fabricated of an electrically insulated material, a threaded stem depending from said housing for mounting said lamp on a support, said stem having an Open channel formed therein, an electrically conductive nut threadably engageable with said stem, a light bulb socket disposed within said housing and having first and second electrical contacts adapted to engage first and second terminals of a light bulb when said light bulb is positioned in said socket, and a ground strap electrically connected to one of said contacts and having a part thereof positioned in said channel to be contacted by said nut when said nut is threaded on said stem.

2. A signal lamp according to claim 1 wherein said stem is formed integral with said housing and also is fabricated of said electrically insulating material.

3. A signal lamp according to claim 2 wherein said stem is hollow and further including a wire electrically connected to the other of said contacts and extending out of said housing through said stem.

4. A signal lamp according to claim 1 wherein at least a portion of said part of said ground strap extends above the roots of the threads on said stem.

5. A signal lamp according to claim 1 wherein the end of said ground strap remote from said one contact is hooked over the end of said stem.

6. A signal lamp according to claim 3 wherein at least a portion of said part of said ground strap extends above the roots of the threads on said stem.

7. A signal lamp according to claim 6 wherein the end of said ground strap'remote from said one contact is 15 hooked over the end of said stem.

References Cited UNITED STATES PATENTS OTHER REFERENCES IBM Technical Disclosure Bulletin, Self-locking 1O Terminal, M. C. Panaro, vol. 3, N0. 6, November'1960,

page 6.

RICHARD E. MOORE, Primary Examiner US. Cl. X.R.

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