GB2033172A

GB2033172A - Strip light fitting

Info

Publication number: GB2033172A
Application number: GB7931900A
Authority: GB
Original assignee: Linolite Ltd
Current assignee: Linolite Ltd
Priority date: 1978-09-26
Filing date: 1979-09-14
Publication date: 1980-05-14
Also published as: GB2033172B

Abstract

A fitting for a double ended tubular lamp 10 has a removable cap 14 at least at one end, the or each cap having a plug 20 which engages in a socket in the fitting and when so engaged, closes a double pole switch arrangement to make an electrical connection for a contact 12 of the fitting, which contact 12 engages a contact on the end of the lamp 10 when the lamp 10 is engaged in the fitting. The cap 14 may be provided with a contact 24 which bridges two fixed contacts 26 to complete the electrical circuit when the cap 14 is engaged with the fitting. <IMAGE>

Description

SPECIFICATION Strip light fitting double pole switch This invention relates to fittings for double-ended electric light bulbs or tubes.

It is desirable for one end contact of double-ended electric light bulbs or tubes to be isolated, whenever it is accessible and the other end contact is in a socket in the light fitting which could be live.

A holder which is adapted to receive one end of a double-ended electric light bulb or tube in accordance with this invention comprises a base portion and a removable cap the cap having at least one plug portion which engages in a socket in the base portion and which when so engages acts to close a double pole switch to make an electrical connection between a mains connection and a contact which is arranged to engage a contact on the end of a bulb or tube when the bulb or tube is engaged in the fitting.

Such a holder may be manufactured and sold separately or it may form an integral part of a fitting in accordance with this invention which is adapted to receive a double-ended electric light bulb or tube, comprises a base portion and a removable end cap for at least one end of a bulb or tube, the or each end cap having at least one plug portion which engages in a socket in the base portion of the fitting and which, when so engaged, acts to close a double pole switch to make an electrical connection for a contact of the fitting, which contact is arranged to engage a contact on the end of a bulb or tube when the bulb or tube is engaged in the fitting.

Thus when the or either end cap is removed from the base portion of the fitting to expose the end of the bulb ortube, the double pole switch is opened breaking the contact for the sockets receiving both ends of the bulb or tube so that both ends of the bulb or tube are isolated.

Such a fitting enables a clearance of at least 8mm to be provided between any live part i.e. a part to be connected to a mains supply and any other electrically conductive part.

The two end caps may either be formed as separate components, or one or both may be formed integrally with a diffuser or shade which extends along the length of the fitting.

The arrangement of plugs on the end caps is a matter of choice. For example, four plugs may be provided in the form of two pairs, one pair on each side of the cap, opposite plugs being connected and each plug carrying a contact to engage a contact in the base portion of the fitting. Another, and in some ways, preferable arrangement is to have two plugs, one plug on each side of the cap, each plug having a contact which, in use, engages across two contacts in the socket so as to make a connection between the socket contacts.

The plugs are preferably provided with a locking device which resiliently mates with a corresponding device or surface in the socket so that the end caps are held in position on the fitting during normal use, but can be removed from the fitting when it is desired to remove the bulb or tube therefrom or to insert a bulb or tube thereinto.

The contact in the fitting which is engaged by the contacts on the ends of the bulb ortube preferably takes the form of a small coil spring which helps resiliently to hold the bulb or tube in position in the fitting whilst at the same time maintaining a good contact with the bulb ortube.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a part section side elevation of a fitting in accordance with the present invention with one end cap shown removed; Figure 2 is a perspective view of the end cap shown in Figure 1; Figure 3 is a perspective view from one side and above of the socket portion of the end of the fitting shown at the left-hand side of Figure 1; Figure 4A is a plan view and Figure 4B is an inverted plan view of the fitting; Figure 5 is a perspective view of the underside of one end with the bottom cover removed; Figure 6 is an end view corresponding to Figure 1; and Figure 7 is a wiring diagram for a fitting in accordance with the present invention.

Referring to the drawings, the fitting comprises a base portion 2 having an upstanding socket 4 at each end to receive an end portion 8 of a tubular lamp 10.

The lamp 10 extends along the length of the fitting with its contact at each end, engaged by a coil spring 12 mounted within the socket 4.

An end cap 14 is provided to cover each end socket 4 of the fitting and to surround and shield the end portion 8 of the tube 10.

The tube 10, when in the fitting, rests on a curved shoulder 16 and is held resiliently between the two springs 12 one acting on each end.

Either two separate end caps may be provided or else the end cap can be formed (as shown in the right hand side of Figure 1) as an integral part of a diffuser or shade 18 which extends along the length of the fitting surrounding the tube 10.

Each end cap 14 is provided with two downwardly depending plug portions 20 one at each side, which engage in sockets 22 (see Figure 4) at each side of the base portion 2 of the fitting.

Each plug is provided with a conductor 24 extending across the inner side of its width which, when the plug is engaged in its socket, bridges two contacts 26 (see Figure 3) positioned on the base which form part of a double pole switch arrangement and which, when connected by the conductor 24 on the plugs 20, act to complete a circuit to the contact spring 12 for the tubular lamp.

Thus, if both end caps 14 are correctly positioned on the fitting, current is fed to the lamp.

It will, of course, be appreciated that the lamp cannot be removed or the conductive ends of the lamps touched, so long as end caps 14 are in position. However, if either end cap 14is removed, both end sockets are isolated so that both ends of the tubular lamp are also isolated and the lamp can safely be removed.

The end caps are provided with barbs 28 on their rear face which engages a shoulder through a slot 30 in the rear of the lamp fitting, and with barbs 32 on the outer side of the plugs which engage under a shoulder beneath the entrance to the sockets 22.

In this way, the end caps are securely held in position on the fitting. When it is desired to remove the end caps the two sides thereof are pressed together disengaging the barbs 32 from their corresponding shoulders and enabling the plug portioned to be pulled out from the sockets 22.

The wires for each end socket 4 of the fitting can readily be connected, in a standard fashion, by pushing the bare ends into holes such as holes 34 (see Figure 5). The bared ends are then engaged and gripped by a flexible contact member to make the contacts.

As it is desirable that a distance of at least 8 mm be present between any metal part and any accessible live part in order for effective isolation to occur, the distance between the two fixed contacts 26 in the base of the fitting will normally be more than 8mm.

Figure 7 shows the electrical wiring of the fitting of the present invention including a double pole switch arrangement 36 at either end of the fitting.

An on/off switch and/or shaver socket may also be incorporated in the fitting.

Claims

1. Aholderforan end of a double-ended electric light bulb or tube comprising a base portion and a removable cap the cap having at least one plug portion which engages in a socket in the base portion and which when so engages acts to close a double pole switch to make an electrical connection between a mains connection and a contact which is arranged to engage a contact on the end of a bulb or tube when the bulb or tube is engaged in the fitting.

2. Afitting adapted to receive a double-ended electric light bulb ortube, the fitting comprising a base portion and a removable end cap for each end of a bulb or tube, each end cap having at least one plug portion which engages in a socket in the base portion of the fitting and which, when so engaged, acts to close a double pole switch to make an electrical connection for a contact of the fitting, which contact is arranged to engage a contact on the end of a bulb or tube when the bulb ortube is engaged in the fitting.

3. Afitting as claimed in Claim 2 wherein each end cap is formed as a separate component.

4. A fitting as claimed in Claim 2, wherein the end caps are formed integrally with a diffuser or shade which is adapted to extend along the length of the fitting.

5. A holder as claimed in Claim 1 or a fitting as claimed in any of Claims 2 to 4wherein each cap has a plug on each side of the cap.

6. A holder as claimed in Claim 1 or a fitting as claimed in any of Claims 2 to 4, wherein each cap has a pair of plugs on each side thereof.

7. A holder of fitting as claimed in either Claims 5 or 6, wherein each plug is provided with a locking device arranged to resiliently mate with a corres ponding device in the socket.

8. A holder as claimed in any of Claims 1 or 5 to 7 or a fitting as claimed in any of Claims 2 to 7, wherein the contact in the base portion of the holder or fitting is a coil spring.

9. A holder as claimed in any of Claims 1 or 5 to 8 or a fitting as claimed in any of Claims 2 to 8 wherein each plug is provided with an electrical contact which when the plug is engaged in the socket in the base portion, bridges electrical connections in the base portion, so as to close the double pole switch.

10. Afitting adapted to receive a double-ended electric light bulb or tube substantially as herein described and with reference to the accompanying drawings.