US3587036A

US3587036A - Electrical contact

Info

Publication number: US3587036A
Application number: US873373A
Authority: US
Inventors: Donald G Mcgregor
Original assignee: ELECTRIX CORP
Current assignee: ITT Corp; ELECTRIX CORP
Priority date: 1969-11-03
Filing date: 1969-11-03
Publication date: 1971-06-22
Anticipated expiration: 1988-06-22

Abstract

An electrical contact, formed in a one-piece metallic construction and having spaced fingers joined thereto in inclined relation that define locking elements for the contact when it is inserted in a bore of a contact block.

Description

United States Patent l 1 1 3,587,036

[72] Inventor Donald G. McGregor [56] References Cited I N 532% UNITED STATES PATENTS P 2,961,634 11/1960 Elliott et a1. 339/276 [22] Filed Nov. 3, I969 [45] Patented Jam 22 1971 3,059,214 10/1962 Heller 339/184 (73] Assignee Electrix Corporation O IG PATENTS Esmond, RJ. 1,238,670 7/1960 France 339/217 (S) 474,525 11/1937 Great Britain 339/217 (S) Primary ExaminerJames A. Leppink [5 ASH-SIG!!! Examiner-Robert Hafer 4 claims, 5 naming at Attorney-Salter and'Michaelson 339/223 ABSTRACT: An electrical contact, formed in a one-piece [51 1 Int. Cl..- HOlr 9/08 metallic construction and having spaced fingers joined thereto (50] Field of Search....' 339/217, in inclined relation that define locking elements for the con- 223, 48, 49 tact when it is inserted in a bore of a contact block.

2a 12 VA? 30 PATENTEnJuuzzlsn 3,587,036

I nventon ,Donald GZMGreyor,

ELECTRICAL CONTACT BACKGROUND OF THE INVENTION The present invention has particular application as a contact button for use in an insulated contact block that may be formed as part of an electric socket, an electrical fixture, light assembly or other electrical device.

Electrical contact buttons of the type embodied in the present invention have been in use heretofore in lighting fixture assemblies and other kinds of assemblies that require a contact button to be secured to the end of a conductor lead. Heretofore, the contacts were secured in a contact block, a bore being provided in the block for receiving the contact therein. Since there was no provision heretofore for securing the contact button within the insulated block, the contact oftentimes worked loose, and relative movement then occurred between the contact and the block in which it was mounted. This, of course, created problems in the operation of the device in which the contact was located, and eventually caused the device to become inoperative.

SUMMARY OF THE INVENTION The present invention includes an electrical contact for insertion into a bore formed in an insulated contact block, the contact comprising a one-piece metallic body portion having a head member and a shank portion joined to the head member. Lugs are formed as part of the shank portion for securing a conductor lead to the contact; and in order to retain the contact in fixed position within the contactblock in which it is inserted, spaced fingers are joined to the shank portion and are inclined outwardly in a direction toward the head portion. The inclined fingers define locking elements for the contact when the shank portion is inserted in the bore of the insulated contact block, the inclination of the fingers permitting the shank portion to be inserted into the bore but preventing withdrawal therefrom.

Accordingly, it is an object of the invention to provide an electrical contact that is formed in a one-piece construction and that includes locking fingers that prevent withdrawal of the contact from a contact block in which it is inserted.

Other objects, features and advantages of the invention will become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.

DESCRIPTION OF THE DRAWING In the drawing which illustrates the best mode presently contemplated for carrying out the present invention:

FIG. 1 is a top plan view of the contact embodied in the present invention;

FIG. 2 is a side elevational view of the contact;

F IG. 3 is a sectional view taken along line 3-3 in F IG. 1;

FIG. 4 is a bottom plan view of the contact; and

FIG. 5 is a sectional view of a contact block showing the contact embodied in the present invention locked therein.

DESCRIPTION OF THE INVENTION Referring now to the drawing, the contact embodied in the present invention is generally indicated at and, although shown in finished form in the various figures, the contact is fabricated of a blank of sheet metal and then formed in the configuration illustrated.

The contact I0 includes a shank portion generally indicated at 12 that is defined by a bottom wall 14 to which sidewalls l6 and 18 are integrally joined. Joined to the bottom wall 14 is a reduced section 20 to which a head portion generally indicated at 22 is integrally connected. As seen in FIGS. 2 and 3, the sidewalls l6 and 18 of the shank portion 12 in the initial fabrication thereof are turned upwardly at substantially right angles with respect to the bottom wall 14 and are cut out intermediate the ends thereof to define

spacedlugs

24, 26 and 28,

30. The

lugs

24 and 28 cooperate as will be described to receive an insulated portion of a conductor lead therebetween, while the

lugs

26 and 30 are adapted to be folded into engaging relation with the exposed wire portion of the conductor lead.

Formed as part of the sidewalls l6 and I8 and located adjacent to the

lugs

26 and 30 are

fingers

32 and 34. As shown in FIG. 1, the

fingers

32 and 34 are inclined outwardly with respect to the head portion 22 and are disposed at substantially a 45 angle with respect to the longitudinal axis of the shank portion 12. As will be described, the

fingers

32 and 34 define locking elements that provide for locking of the contact 10 within a bore of a contact block. Since it is desirable that the

fingers

32 and 34 make a point contact engagement with the sidewalls of the bore in which the contact 10 is inserted, the lateral dimension of the fingers is substantially reduced with respect to the longitudinal dimension of the

lugs

24, 28 and 26, 30. This relationship is illustrated in FIG. 2 wherein the lateral dimension of the fingers represented at l is considerably less than the height indicated at h of the lugs.

The head portion 22 of the contact 10, which is formed as an integral part of the contact construction and defines an extension of the shank portion 12, includes a convex button 36 joined to the reduced extension by an inclined portion 38. A reversely turned portion 40 is joined to the button 36 and has an elongated extension 42 joined thereto that overlies the reduced section 20 and the bottom wall 14 of the shank portion 12. As will be described, the extension 42 is relatively long and extends substantially the length of the channel defined by the

opposed walls

16 and 18. The conductor lead that is received in the channel is locked into engagement with the extension 42 and thus acts to positively retain the button 36 in the position thereof for making electrical engagement with a complementary contact.

A conductor cable or lead generally indicated at 44 in FIG. 4 is attached to the contact 10 by locating a sheath portion 46 thereof between the

lugs

24 and 28 and then locating the stripped cable 47 between the

lugs

26, 30 and in overlying relation on the extension 42. The

lugs

24 and 28 are then folded into clamping relation over the sheath 46, and the

lugs

26, 30 are similarly folded into clamping engagement with the exposed cable 47, whereby the conductor cable 44 is firmly secured to the contact 10.

In use of the contact 10 as contemplated by the present invention, the contact is normally inserted into a contact block such as represented at 48 in FIG. 5. Formed in the contact block 48, which is preferably molded of an insulating plastic material, is a bore 50. A countersunk portion 52 is formed in the contact block 48 for receiving the contact button 22, the countersunk portion 52 communicating with a reduced bore 54 that defines a shoulder 56 with the bore 50. The diameter of the reduced bore 54 is somewhat less than the diameter of the contact button 22, and thus the button 22 is received within the countersunk portion 52 but is prevented from being withdrawn into the bore 54.

The contact 10, together with the conductor cable 44, is threaded into the bore 50 in the block 48, the inclination of the

fingers

32 and 34 being such that they will engage the sidewalls of the bore 50 when the contact is fully inserted into the block 48. Since the

fingers

32 and 34 have a spring action because of the metallic material from which the contact 10 is formed, they will permit insertion of the contact through the reduced bore 54. When the

fingers

32 and 34 clear the shoulder 56, they snap thereunder into engagement with the walls of the bore 50 and will prevent withdrawal of the contact 10 outwardly of the contact block 48. Since the button 22 blocks the contact against inward movement of the block 48 and the

fingers

32 and 34 prevent outward movement of the contact, it is seen that the contact is firmly secured within the contact block 48. Movement of the contact 10 with respect to the block 48 is thus prevented, and the contact button 22 is firmly fixed in position and will be available for positive electrical engagement with a complementary contact that is moved into engagement therewith.

What I claim is:

1. An electrical contact for insertion into a bore formed in an insulated contact block, comprising a one-piece metallic body portion having a head member formed with a convex portion that is engageable by an external contact member for establishing electrical communication therewith, a shank portion joined to said head member and extending inwardly thereof, a reduced extension joined to said head member and extending reversely with respect thereto for location in overlying relation on said shank portion, said reduced extension and the portion of said shank portion over which said extension lies defining an elongated neck section, opposed and spaced lugs joined to said shank portion and being foldable for capturing a wire conductor of an electrical lead therebetween, and a pair of spaced fingers integrally joined to said shank portion adjacent to said lugs and being inclined outwardly in a direction toward said head portion, the longitudinal dimension of said fingers being somewhat less than that of said elongated neck section, wherein the outermost ends of said fingers are substantially spaced from said head member said inclined fingers defining locking elements for said contact when the shank portion thereof is inserted in the bore of said insulated contact block, the inclination of the fingers permitting the shank portion to be inserted into said bore, but preventing withdrawal therefrom by engaging the sidewalls thereof.

2. An electrical contact as set forth in claim 1, said lugs being initially formed substantially at right angles to said extension and the portion of the shank portion on which said extension overlies, and the lateral dimension of the fingers being substantially less than the longitudinal dimension of said lugs.

3. An electrical contact as set forth in claim 2, said fingers being inclined with respect to the longitudinal axis of said shank portion at an angle of substantially 45.

4. An electrical contact as set forth in claim 1, said extension having a longitudinal dimension that is sufficient for locating the wire conductor in overlying relation therewith when the lugs are folded over the wire conductor.

Claims

3. An electrical contact as set forth in claim 2, said fingers being inclined with respect to the longitudinal axis of said shank portion at an angle of substantially 45*.