GB2118380A

GB2118380A - An improved lampholder

Info

Publication number: GB2118380A
Application number: GB08310037A
Authority: GB
Inventors: Norman Warburton
Original assignee: APW Electronics Ltd
Current assignee: APW Electronics Ltd
Priority date: 1982-04-14
Filing date: 1983-04-13
Publication date: 1983-10-26
Also published as: GB8310037D0

Abstract

A lampholder (1) comprising a substantially tubular housing (2) of electrically insulating material, open at each of its ends, which is slit longitudinally of its length at at least one position around its periphery, the parts of the tubular housing bounding the or each longitudinally extending slit being detachably secured together; means (4) at one end of the tubular housing with which a light bulb (5) can be mechanically and detachably secured; and, intermediate of the ends of and integral with the tubular housing, at least one support (8) of electrically insulating material on which are mounted two electric contact assemblies (3) of metal or metal alloy, each of which contact assemblies includes means (15) for effecting electrical connection to a conductor (16) of an electric wiring cable (12) passing into the tubular housing through said other open end (11) of the tubular housing and a resilient or spring loaded terminal (18) for engagement with one contact of a light bulb. <IMAGE>

Description

SPECIFICATION An improved lampholder This invention relates to a lampholder for electrical connection to an end of an electric cable.

It is an object of the invention to provide an improved lampholder of this kind which is simple in construction and inexpensive to manufacture.

According to the invention, the improved lampholder comprises a substantially tubular housing of electrically insulating material, open at each of its ends, which is slit longitudinally of its length at at least one position around its periphery, the parts of the tubular housing bounding the or each longitudinally extending slit being detachably secured together; means at one end of the tubular housing with which a light bulb can be mechanically and detachably secured; and, intermediate of the ends of and integral with the tubular housing, at least one support of electrically insulating material on which are mounted two electric contact assemblies of metal or metal alloy, each of which contactassemb- lies includes means for effecting electrical connection to a conductor of an electric wiring cable passing into the tubular housing through said other open end of the tubular housing and a resilient or spring loaded terminal for engagement with one contact of a light bulb.

Preferably, the tubular housing is made of a resilient plastics insulating material. The tubular housing may be slit longitudinally of its length at one position only around its periphery to divide the housing longitudinally of its length into two parts which, at a position diametrically opposite said slit, are effectively hinged together via a longitudinally extending fin integral with said two parts of the housing, or the tubular housing may be slit longitudinally of its length at two diametrically opposed positions around its periphery to divide the housing longitudinally of its length into two separate parts. In each case, preferably the parts of the housing bounding the or each longitudinally extending slit are detachably secured together by means of an integral readily releasable resilient snap fitting.

The means at one end of the tubular housing for enabling a light bulb to be mechanically and detachably secured in the lampholder preferably takes the form of a sleeve of metal or metal alloy which has a pair of diametrically opposed L-shaped slots for engagement with the bayonet pins of a light bulb or carries a screw thread for engagement with a screw threaded light bulb and which is slidably engaged within said end part of the tubular housing in such a way that the sleeve is restrained against lengthwise and circumferential movement with respect to the housing.Preferably, the sleeve is retained between an inwardly extending circumferential flange at the extreme end of the tubular housing and, spaced from said end of the housing, an inwardly extending shoulder or inwardly extending shoulders on the wall of the housing; preferably, also, the sleeve is keyed to the wall of the housing to restrain it against circumferential movement with respect to the housing.

The opening at the other end of the tubular housing is preferably of such a form that, when a length of electric wiring cable is passed into the tubular housing through said opening and the parts of the tubular housing are detachably secured together, the electric cable passing through said opening will be gripped between the parts to restrain the cable against lengthwise movement with respect to the housing.

To provide for the attachment of a shade to the lampholder, preferably the tubular housing has at a position intermediate of its ends, an outwardly extending circumferential shoulder and a portion of the tubular housing between said shoulder and the end of the housing surrounding the metal sleeve is externally screw threaded and carries an internally screw threaded collar for locking the ring of a shade which has been slipped over the tubular housing against the outwardly extending shoulder on the housing.

Preferably, each electric contact assembly is mounted in a separate support integral with the tubular housing, the support rt of one electric contact assembly being integral with one part of the tubular housing and the support of the other electric contact assembly being integral with the other or another part of the tubular housing.

In each electric contact assembly, the means for effecting electrical connection to a conductor of an electric wiring cable may take any convenient form but, preferably, to simplify connection of the conductors of an electric cable to the electric contact assemblies, said connecting means takes the form of an insulation displacement connector to which an insulated conductor of an electric cable can be electrically connected without the necessity of stripping any insulation from the condoctor. In this case, preferably the insulation displacement connector is integral with a tubular metal housing in which is slidably mounted and from which protrudes a spring loaded plunger constituting the terminal for engagement with one contact of a light bulb.The tubular metal housing is preferably a snap fit in an inwardly extending bracket integral with the wall of the tubular housing and constituting the support for the electric contact assembly.

if desired, the improved lampholder may also house a switch. In a preferred embodiment, the switch is detachably mounted on a support of electrically insulating material integral with the tubular housing and has a slidable operating rod which protrudes through diametrically opposed holes in the tubular housing.

Since the tubular housing of the improved lampholder is divided longitudinally of its length into at least two parts which can be readily separated, attachment of the improved lampholderto an end of an electric cable is facilitated and subsequent assembly of the improved lampholder is simple. Moreover, the improved lampholder can be built up of very few parts and can be readily connected to an end of an electric cable and assembled by an unskilled user.

The invention is further illustrated, by way of example, by the accompanying drawings in which: Figure 1 is a sectional side view of a preferred lampholder; Figure 2 is a isometric view (partly cut away) of the electric contact assembly used in the lampholder shown in Figure 1; and Figure 3 is a isometric view of the hinged parts of the tubular housing of the lampholder shown in Figure 1.

Referring to Figure 1, the lampholder 1 comprises a substantially tubular housing 2 of resilient plastics electrically insulating material, two electric contact assemblies 3, and a metal sleeve 4 for securing the light bulb 5.

The housing 2 (Figure 3) is slit longitudinally of its length into two parts which are intagrally hinged together by a longitudinally extending fin 6. The two parts are secured together by integral resilient snap fittings 7. Each part of the housing 2 has an integral support8 on which a contact assembly 3 is mounted.

An inwardly extending circumferential flange 9 at one end of each part of the housing 2 and an inwardly extending shoulder 10 retain the metal sleeve 4 within the housing 2 when the two parts are snap fitted together. The other end 11 of the parts of the housing 2 are so shaped to provide a cord grip for an electric cable 12 (Figure 1) when the two parts are snap fitted together.

A portion of the housing 2 between an outwardly extending circumferential shoulder 13 and the open end of the housing within which the bulb 5 is secured is externally screw threaded and carries an internally threaded collar 14 (Figure 1) for securing a shade (not shown) to the housing.

Each electric contact assembly 3 (Figure 2) comprises an insulation displacement connector 15 to which an insulated conductor 16 (Figure 1) ofthe cable 12 can be electrically connected; a boss (now shown) to prevent withdrawal of the conductor after insertion; an integral metal tubular housing 17 within which is slidably mounted a protruding plunger 18; and a coil spring 19 acting on the plunger. Each plunger 18 constitutes a terminal for engagement with a contact of the bulb 5.

Claims

1. A lampholdercomprising a substantiallytubu larhousing of electrically insulating material, open at each of its ends, which is slit longitudinally of its length at at least one position around its periphery, the parts of the tubular housing bounding the or each longitudinally extending slit being detachably secured together; means at one end of the tubular housing with which a light bulb can be mechanically and detachably secured; and, intermediate of the ends of and integral with the tubular housing, at least one support of electrically insulating material on which are mounted two electric contact assemblies of metal or metal alloy, each of which contact assemblies includes means for effecting electrical connection to a conductor of an electric wiring cable passing into the tubular housing through said other open end of the tubular housing and a resilient or spring loaded terminal for engagement with one contact of a light bulb.

2. A lampholder as claimed in Claim 1,wherein the tubular housing is made of a resilient plastics insulating material.

3. A lampholder as claimed in Claim 1 or Claim 2, wherein the tubular housing is slit longitudinally of its length at one position only around its periphery to divide the housing longitudinally of its length into two parts which, at a position diametrically opposite said slit, are effectively hinged together via a longitudinally extending fin integral with said two parts of the housing.

4. A lampholder as claimed in any one of the preceding Claims, wherein the parts of the housing bounding the or each longitudinally extending slit are detachably secured together by means of an integral readily releasable resilient snap fitting.

5. A lampholder as claimed in any one of the preceding Claims, wherein the light bulb securing means comprises a sleeve of metal or metal alloy which has a pair of diametrically opposed L-shaped slots for engagement with the bayonet pins of a light bulb or carries a screw thread for engagement with a screw threaded light bulb and which is slidably engaged within said end part of the tubular housing in such a way that the sleeve is restrained against lengthwise and circumferential movement with re spect to the housing.

6. A lampholder as claimed in Claim 5, wherein the sleeve is retained between an inwardly extending circumferential flange at the extreme end of the tubular housing and, spaced from said end of the housing, an inwardly extending shoulder or inwardly extending shoulders on the wall of the housing.

7. A lampholder as claimed in Claim 6, wherein the sleeve is keyed to the wall of the housing to restrain it against circumferential movement with respect to the housing.

8. A lampholder as claimed in any one of the preceding Claims, wherein the opening at the other end of the tubular housing is of such a form that, when a length of electric wiring cable is passed into the tubular housing through said opening and the parts of the tubular housing are detachably secured together, the electric cable passing through said opening will be gripped between the parts to restrain the cable against lengthwise movement with respect to the housing.

9. A lampholder as claimed in any one of the preceding Claims, wherein the tubular housing has at a position intermediate of its ends, an outwardly extending circumferential shoulder and a portion of the tubular housing between said shoulder and the end of the housing surrounding the metal sleeve is externally screw threaded and carries an internally screw threaded collar for locking the ring of a shade which has been slipped over the tubular housing against the outwardly extending shoulder on the housing.

10. A lampholder as claimed in any one ofthe preceding Claims, wherein each electric contact assembly is mounted in a separate support integral with the tubular housing, the support of one electric contact assembly being integral with one part of the tubular housing and the support of the other electric contact assembly being integral with the other or another part of the tubular housing.

11. A lampholder as claimed in any one of the preceding Claims, wherein the electrical connection means comprises an insulation displacement connector.

12. A lampholder as claimed in Claim 11, wherein the insulation displacement connector is integral with a tubular metal housing in which is slidably mounted and from which protrudes a spring loaded plunger constituting the terminal for engagement with one contact of the light bulb.

13. A lampholder as claimed in Claim 12, wherein the tubular metal housing is a snap fit in an inwardly extending bracket integral with the wall of the tubular housing and constituting the support for the electric contact assembly.

14. A lampholder as claimed in any one of the preceding Claims, wherein a switch is detachably mounted on a support of electrically insulating material integral with the tubular housing and has a slidable operating rod which protrudes through diametrically opposed holes in the tubular housing.

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