US3582861A

US3582861A - Socket assembly having ground pin

Info

Publication number: US3582861A
Application number: US763208A
Authority: US
Inventors: Richard J Mangini
Original assignee: United Carr Inc
Current assignee: United Carr Inc
Priority date: 1968-09-27
Filing date: 1968-09-27
Publication date: 1971-06-01
Anticipated expiration: 1988-06-01
Also published as: GB1282626A

Abstract

This invention is directed at an electric socket having an insulating insert engaged within a metal shell. The insert has a ground pin associated with it comprising a head portion and a shank portion extending therefrom. The head portion is adapted to fit within a slot formed in a flange of the insert so that the upper surface of the head portion lies on the same plane as the upper surface of the flange and the shell is electrically engaged with the head portion.

Description

United States Patent Inventor Richard J. Mangini Hudson, Mass.

App]. No. 763,208

Filed Sept. 27, 1968 Patented June 1, 1971 Assignee United-Carr incorporated Boston, Mass.

SOCKET ASSEMBLY HAVING GROUND PIN 1 Claim, 6 Drawing Figs.

u.s.cl 339/14,

339/170 lnt.Cl non 3/06 Field 6: Search 339/14,

[56] References Cited UNITED STATES PATENTS 1,782,527 11/1930 Bennett 339/14 2,959,761 11/1960 Weber et al.. 339/170 Primary Examiner-Marvin A. Champion Assistant Examiner-Robert A. Hafer Att0rneysPhilip E. Parker, Gordon Needleman, James R.

OConnor, John Todd and Hall and l-loughton ABSTRACT: This invention is directed at an electric socket having an insulating insert engaged within a metal shell. The insert has a ground pin associated with it comprising a head portion and a shank portion extending therefrom. The head portion is adapted to fit within a slot formed in a flange of the insert so that the upper surface of the head portion lies on the same plane as the upper surface of the flange and the shell is electrically engaged with the head portion.

' ,PATEN'TEDJUN nan (PRIOR ART) F l G.

FIG. 3

F l G. 5

F IG. 6

iNvENToR RICHARD J. MANGlNl W Mala ATTORNEY SOCKET ASSEMBLY HAVING GROUND PIN BACKGROUND OF THE INVENTION There are a number of applications where an electric bulb socket is required to be grounded through its shell and through a ground pin which is engaged therewith. Some of the early socket designs, many of which are still in use, utilized a plug button or other attaching device as a means of grounding the shell to a support, such as the chassis of a car. The socket shown in FIG. I uses an insulating insert 1 within which a pair of spring-loaded terminals 2 are axially located. A ground pin 3, of tubular configuration, is slid into an axial engagement aperture formed in the upper surface of the insert I and through a flange 4 which extends from a wall of the insert. A lip formed on the upper surface of the ground pin 3 abuts the upper surface of the insert I for about 270 of the circumference of the ground pin 3. The remaining portion of the circumference is sheared downwardly to overlie the flange 4 with the sheared portion of the lip extending slightly beyond the flange 4. The subassembly of the insert 1 and the ground pin 3 can now be dropped into a metal socket shell 5 which has a shoulder element formed therein. The pin 3 and a portion of the insert 1 can pass beyond the area defined by the socket 5 while the lower surface of the flange 4 butts against the shoulder. The socket shell 5 is then bumped inwardly to abut the sheared portion of the lip to form an electrical and mechanical engagement.

There are several disadvantages to this method for forming a ground. For instance, the cost of the secondary operation is rather high in relation to the part being manufactured. Furthermore, the position of the sheared piece must be accurately predetermined to assure satisfactory engagement between the indentation formed in the socket shell and the ground pin. This last requirement is made even more difficult because the sheared piece comes to rest on top of the flange of the insert. Note that when the shell is bumped inwardly it pushes against the sheared portion of the lip creating the danger of breaking the sheared portion thereby destroying the required electrical connection.

SUMMARY OF THE INVENTION This invention is directed at a lamp socket which comprises a tubular metal shell and an electrically insulating insert. The insert assembly includes a plastic body having means of engaging a pair of terminal elements as well as means of engaging a pair of contacts adapted to engage a light bulb. The insert is also engaged to a headed ground pin which fits within a slot formed in a flange of the body. The head of the ground pin has its upper surface on the same plane as the upper surface of the flange and also has an arced wall forming a continuation of the outer wall of the flange.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a top plan view ofa socket which forms part of the prior art;

FIG. 2 is a side elevation of the insert subassembly of the invention showing spring-loaded contacts, blade terminals and the ground pin on the opposite side;

FIG. 3 is a top plan view of the insert subassembly shown in FIG. 2;

FIG. 4 is a side elevation of the insert subassembly shown in FIG. 2 with the ground pin uppermost;

FIG. 5 is a side elevation of the ground pin; and,

FIG. 6 is a side elevation of the insert subassembly engaged to a socket shell, the socket shell broken off.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawing there is shown a socket 10 comprising a metallic shell 12, an insulating insert 14 flxed within the metallic shell 12 and having a pair of blade terminations I6 and a ground pin 18 engaged therewith.

The insert 14 is formed of an organic polymeric material such as a general purpose phenolic, modified polyphenyleneoxide, a polyacetal resin or nylon. It has a pair of

sidewalls

20, 22 in spaced parallel relationship with each other connected by a pair of spaced arced end walls 24. The insert 14 includes two

apertures

26, 28 which are axially formed through its upper surface 30 and which extend down through the lower surface 32. Retaining slots (not shown) extend on each side of the

apertures

26, 28 respectively. These slots are formed on the lower surface 32 but not on the upper surface 30. An arced flange 38 extends from the sidewall 22 and another arced flange 40 extends from the sidewall 20 on the same plane as the flange 38. An engagement aperture 42 is formed through the arced flange 40 having an axis in spaced parallel relationship to the axes of the

apertures

26, 28 and being enclosed for the major portion of its length by an arced covering portion 44. The engagement aperture 42 divides the flange 40 into two portions as shown in FIG. 3. The covering portion 44 can act as an indexing means when engaged with a notch formed through the shoulder of the shell 12. The engagement aperture 42 is adapted to receive the ground pin 18 which comprises a solid cylindrical shank portion 46 and an integral head portion 48. The head portion 48 has a pair of

flat sidewalls

50, 52 in angular relation to each other merging into an arced rear surface of the head portion 48 which is a continuation of the shank portion 46. The head portion 48 fonns a shoulder 54 with the shank portion 46.

To engage the ground pin 18 with the insert 14 the shank portion 46 is passed down through the engagement aperture 42 until the shoulder 54 butts against the upper edge of the covering portion 44. In this position the upper surface of the head portion 48 is flush with the upper surface of the arced flange 40 and the rounded edge of the head portion 48 provides a continuation of the arced surface of the flange 40. Each portion of the flange 40 adjacent the head portion 48 is ehamfered.

A pair of tubular contacts 56 each a headed eyelet comprising a body portion having one end closed by a flangelike portion. The body portion of the contact 56 is circumscribed by a compression spring 58 which is butted against the flangelike portion and then a single subassembly of the contact 56 and the spring 58 is placed into each

aperture

26, 28 so that the lower terminal end of the compression spring 58 butts against the upper surface of the insert 14 and then the open end of the contact 56 is flared outwardly to engage an internal shoulder formed in close proximity to the upper surface of the insert 14 and in the wall of each of the

apertures

26, 28. The contact 56 is now adapted to move in an axial direction up and down against the compression spring 58 but through the flaring operation is securely held in engagement with the insert 14.

The terminals 16 each comprises a comparatively broad rectangular blade portion having an integral engagement portion extending from a short edge thereof. The engagement portion comprises a flexible strip of narrower width than the blade portion which is bent back upon itself defining a pair of arms. One of the arms is shorter than the other and both arms are bowed outwardly. To engage a terminal 16 with a tubular contact 56, the engagement portion is passed into one of the

apertures

26, 28 from the lower surface 32 until the arms of the engagement portion pass into the contact 56 while the blade portion engages in the slots. A wiping contact is thereby maintained between the engagement portion and the inner surface of the contact 56.

The tubular shell 12 and the insert subassembly are engaged in the following manner: The tubular shell 12 has two inturned shoulders adjacent one end, one of the shoulders having a notch formed therethrough. The insert subassembly is dropped down into the shell with the contacts 56 pointing away from the inturned shoulders and the

flanges

38, 40 are butted against the shoulders while the covering portion 44 rests within the notch formed in one of the inturned shoulders. The metal of the shell is now bumped inwardly providing a dimple or protuberance as shown in FIG. 6 whereby it overlies shell, the protuberance overlying a portion of the head portion in abutting relation, and the insert having means associated therewith for electrically engaging a bulb or the like and the head portion having an upper surface and the insert having an external flange having an upper surface, both of said upper surfaces being on the same plane when the ground pin is fully engaged with the insert.

Claims

1. An electric socket comprising a shell providing a cavity, an insert engaged within the cavity having a slot formed therein, and a ground pin having a head portion and a shank portion, the head portion set within the slot and engaging with an inwardly projecting protuberance formed in the tubular shell, the protuberance overlying a portion of the head portion in abutting relation, and the insert having means associated therewith for electrically engaging a bulb or the like and the head portion having an upper surface and the insert having an external flange having an upper surface, both of said upper surfaces being on the same plane when the ground pin is fully engaged with the insert.