GB2145883A

GB2145883A - Lampholders

Info

Publication number: GB2145883A
Application number: GB08330515A
Authority: GB
Inventors: John Henry Thompson
Original assignee: Pressac Ltd
Current assignee: Pressac Ltd
Priority date: 1983-09-02
Filing date: 1983-11-16
Publication date: 1985-04-03
Also published as: GB8330515D0; GB8323535D0

Abstract

A lampholder (12) designed for inhibiting removal of a lamp (11) comprises a housing (13) and a pair of contact elements (14), each contact element being generally U- shaped in plan for receiving the wedge base (25) of a lamp. The opposed limbs (15, 16) of each U are disposed on opposite sides of the wedge base and make electrical contact therewith. An inturned abutment (20) of a limb (15) engages a recess in a wedge base (25) to inhibit removal of the lamp. The lamp is further held by resilient pressure of a limb (15) of each contact element (14) forcing the wedge base (25) against the other limb (16). <IMAGE>

Description

SPECIFICATION Lampholders This invention relates to lampholders and more particularly concerns lampholders of the type used for lamps having wedge-shaped bases (herein referred to wedge bases).

A known lampholder comprises a plastics moulding which defines a recessed lamp socket. A pair of generally U-shaped contact elements are retained in the socket to receive the wedge base of a wedge base lamp.

It has been found to be desirable to inhibit the removal of lamps from lampholders in certain applications, such as automotive applications. In such cases, it is common to supply lamp-lampholder assemblies to a manufacturer or end-user and it is of considerable inconvenience to a manufacturer if lamps have become disengaged from iampholders during transport.

It is an object of the present invention to provide an improved iampholder which overcomes this problem.

According to the present invention, we provide a lampholder which is adapted for inhibiting removal of a lamp when inserted in the lampholder, the lampholder comprising a housing which defines a lamp socket, and a pair of contact elements which are retained in the lamp socket, each contact element being generally U-shaped in plan and being arranged so that, when the lampholder is in use, each U receives the wedge base of a lamp, and the opposed limbs of each U are disposed on opposite sides of the wedge base and make electrical contact therewith, at least one limb of at least one of said elements including an inturned abutment for engagement in a recess in a wedge base of the lamp to inhibit removal thereof.

The lampholder overcomes the disadvantage of the known lampholders whereby a lampholder becomes disengaged from a lamp mounted thereon. The lampholder is suitable for use with known kinds of lamp so that no modification of the wedge bases of the known lamps are required.

Preferably, the limbs of at least one of the elements are adapted to grip the wedge base of a lamp so that the lamp does not require support from the housing. This gives better tolerances in the manufacture of a lampholder in accordance with the invention, since it is easier to control the manufacture of the metal contact elements than to control a plastics moulding. Furthermore, any plastic deformation of the moulding due to the moulding becoming hot will not affect the retention of a lamp in the lampholder.

Preferably, at least one limb of at least one of the elements is formed of a resiliently deformable material, the limbs being arranged so that the one limb acts as a pressure element when the lampholder is in use, being resiliently deformed to urge a wedge base of a lamp towards the other limb which acts as an anvil, the pressure element and anvil thereby gripping the wedge base. In the preferred embodiment of lampholder, the limb which comprises an abutment acts as a pressure element, and the other one of the limbs act as an anvil.

In one particular embodiment of the invention, each element comprises an abutment, and the abutments of respective elements are disposed on opposite sides of the wedge base.

The invention also includes a lamp-lampholder assembly comprising a lampholder as hereinbefore described and a lamp which is retained in the lampholder, the lamp being of the kind which comprises a wedge base.

The invention is hereinafter more particularly described with reference to the accompanying drawings, in which: Figure 1 is a perspective view of an assembly of a lamp and a lampholder; Figure 2 in a perspective view in crosssection of the assembly of lamp and lampholder; Figure 3 is an elevation of an element of the lampholder; and Figure 4 is an elevation of the element which is orthogonal to the elevation shown in Fig. 3.

An assembly 10 comprises a lamp 11 and a lampholder 1 2. The lampholder comprises a housing 1 3 which is formed of a plastics material and which defines a socket 21 in the form of a recess. The lampholder further comprises a pair of substantially identical contact elements 14 for retaining the lamp in the socket of the lampholder. The contact elements in addition provide a means for electrically connecting the lamp in a circuit, and thus are suitably formed of a metal. The contact elements are resiliently deformable.

The contact elements 14 are located in the housing 1 3 on opposite sides thereof. Each element comprises a support limb 22 which is adjacent an inwardly facing surface of the recess, and which extends over a lip 24 of the recess. A portion of the support limb which is adjacent the inwardly facing surface of the recess comprises an attachment tongue 23 for retaining the element in the socket 21. A portion of each element on the outside of the recess is an electrical contact portion 1 7.

Each element 1 4 comprises a portion inside the recess which is generally U-shaped in plan and which comprises a first limb 1 5 and a second limb 16. A wedge base 25 of the lamp extends generally between the elements, and respective inwardly facing surfaces of the limbs extend partially along the length of the wedge base and engage electrical contacts thereon. A first portion 26 of the first limb extends generally upwardly from the base of the recess. An end portion of the first limb is turned inwardly through approximately 1 50, to form an abutment 20. The junction between the abutment and the first portion of the first limb forms an upwardly facing curved surface.

The second limb 1 6 comprises a first portion 1 8 which is cranked inwardly near the base of the recess and which extends upwardly generally parallel to the first portion 26 of the first limb 1 5. An end portion of the second limb is turned outwardly to form an upper portion 1 9 which is approximately perpendicular to the first portions of the first and second limbs. The first portion and upper portion of the second limb are formed so as to be resistant to a bending force applied to the second limb in a direction away from the first limb.

When the lamp 11 and lampholder 1 2 are separate components to be assembled, the lamp is inserted into the recess, wedge base first, with the wedge base extending in a direction which leads from one of the elements 14 to the other. The abutments 25 guide the wedge base to a position between the limbs of the respective elements. As the lamp is guided into the recess, the abutments ride over respective opposite facing surfaces of the wedge base and the first limbs are resiliently deformed by being bent away from the respective second limbs of the elements.

The lamp is fully inserted in the lampholder when the abutments have slid into recesses on opposite sides of the wedge base, and when the first or second limbs of each element are in electrical contact with contact elements on the wedge base. It is preferred that the elements be formed so that the second limbs come into contact with the contact elements on the wedge base.

When the lamp is thus mounted in the lampholder, the U of each element 14 receives the wedge base of the lamp, and the opposed limbs of each U are disposed on opposite sides of the wedge base. The abutments are disposed on opposite sides of the wedge base. Each first limb is resiliently deformed so as to bias the wedge base of the lamp towards the opposite limb of the U so that the limbs of the elements grip the wedge base of the lamp. The first limb of each U acts as a pressure element to urge the wedge base towards the second limb which acts as an anvil.

The abutments 20 of the elements inhibit removal of the lamp from the assembly of lamp and lampholder. When an attempt is made to remove the lamp, leading edges 28 of the abutments engage in the recesses in of the wedge base. A continued effort to remove the lamp results in the wedge base being jammed between the leading edges and the inwardly cranked first portions 18 of the second limbs 16.

Claims

1. A lampholder which is adapted for inhibiting removal of a lamp when inserted in the lampholder, the lampholder comprising a housing which defines a lamp socket, and a pair of contact elements which are retained in the lamp socket, each contact element being generally U-shaped in plan and being arranged so that, when the lampholder is in use, each U receives the wedge base of a lamp, and the opposed limbs of each U are disposed on opposite sides of the wedge base and make electrical contact therewith, at least one limb of at least one of said elements including an inturned abutment for engagement in a recess in a wedge base of the lamp to inhibit removal thereof.

2. A lampholder in accordance with Claim 1 wherein the limbs of at least one of the elements are adapted to grip the wedge base of a lamp.

3. A lampholder in accordance with either preceding claim wherein at least one limb of at least one of the elements is formed of a resiliently deformable material, the limbs being arranged so that the one limb acts as a pressure element when the lampholder is in use, being resiliently deformed to urge a wedge base of a lamp towards the other limb which acts as an anvil, the pressure element and anvil thereby gripping the wedge base.

4. A lampholder in accordance with Claim 3 wherein the limb which comprises the abutment acts as a pressure element, and the other limb acts as an anvil.

5. A lampholder in accordance with any preceding claim wherein each element comprises an abutment, and the abutments of respective elements are disposed on opposite sides of the-wedge base.

6. A lamp-lampholder assembly comprising a lampholder in accordance with any preceding claim and a lamp which is retained in the lampholder, the lamp being of the kind which comprises a wedge base.

7. A lampholder substantially as herein described, with reference to and as shown in the accompanying drawings.

8. A lamp-lampholder assembly substantially as herein described with reference to and as shown in the accompanying drawings.