GB2100400A

GB2100400A - Lamp fitting

Info

Publication number: GB2100400A
Application number: GB8118212A
Authority: GB
Original assignee: Linolite Ltd
Current assignee: Linolite Ltd
Priority date: 1981-06-12
Filing date: 1981-06-12
Publication date: 1982-12-22
Also published as: GB2100400B

Abstract

A lamp fitting comprises two sockets (3,4), a double pole switch (30) connected to the sockets, a cover member (10) slidable between a "bulb retain" position and a "bulb release" position and a manual actuating member (13) movable to lock the cover member (10) in the "bulb retain" position. The cover member (10) interlocks with the switch (30) so that a bulb cannot be removed whilst the switch is "on", and conversely when the switch is "off" the cover member (10) can be operated and the bulb removed safely from the fitting without danger. <IMAGE>

Description

SPECIFICATION Lamp fitting The present invention relates to lamp fittings.

Certain lamp fittings are particularly prone to danger when removing lamp bulbs from the fittings. An example of this is a strip lamp fitting in which there are two sockets one at each end to receive a bulb with a contact at each end.

A lamp fitting according to the invention comprises a lamp bulb socket means, a double pole switch connected to the socket means to make or break both electrical power connections to the fitting, a lamp bulb retaining means arranged to prevent removal of the bulb from the fitting and movable between a "bulb remove" position and a "bulb retain" position, the retaining means being locked against movement to the "remove position" when the switch is made in an "on" position.

Such a retaining means interlocks with the double pole switch so that the bulb cannot be removed whilst the switch is "on" and when the switch is broken and in an "off" position the retaining means can therefore be safely operated to remove the bulb from the fitting.

Preferably the socket means comprises two sockets enabling reception of an elongate bulb, with an electrical contact at eadh end. In a preferred embodiment the retaining means for such an elongate bulb comprises a cover member slidable along a path substantially parallel to the axis of the bulb, the switch being located in the path of the cover member, the cover member having an interlock portion preventing movement of the cover member along the path to the "bulb release" position when the switch is in the "on" position. In the preferred embodiment the cover member has a slot allowing movement of the cover member along the path over the switch to the "bulb release" position when the switch is in the "off" position. The switch in the preferred embodiment has a manual actuating member movable across the path from the "on" to the "off" position.

An embodiment of the invention by way of example will now be described with reference to the accompanying drawings in which: Figure 1 is a perspective view of a lamp fitting according to the present invention with the switch in the "on" position, Figure 2 is a plan view of the switch and locking sockets of the fitting of Fig. 1 with the switch in the "off" position and the retaining means in the "bulb retain" position, Figure 3 is a plan view similar to Figure 2 but with the retaining means in the "bulb release" position, and Figure 4 is a cross section of the socket of Figure. 1 taken at A-A of Figure 1.

In Figure 1 there is shown a lamp fitting 1 with a casing 2 in which is mounted a first socket 3, a second socket or switch locking socket 4 and an elongate strip light bulb 5 held between the sockets 3 and 4. The bulb 5 has an axis 6, the sockets being spaced apart in the axis 6.

In the second socket 4 there is a cover member 10 slidable along a path 11 substantially parallel to axis 6. The cover member acts as a part of a means to retain the bulb and is slidable along the path 11 from a "bulb retain" position as in Fig. 1 to a "bulb release" position as in Fig. 3. The cover member is however only enabled to move to the "bulb release" position if a manual actuating member 13 is moved upward from the "on" position shown in Fig. 1 across the path 11 in a direction indicated by arrow 14 so that it is aligned with a slot 1 5 in the cover member to the switch "off" position as shown in Fig. 2.

Further details of the second socket can be seen in Figure 4. The cover member 10 slides in lateral grooves 18 and has a bulb retaining portion 20 which when the cover member in the Fig. 4 position acts on the bulb ferrule 22 to hold the bulb in the retained position.

In Fig. 4 can also be seen an electrical contact 24 which is shown in firm lines in a position it would assume with no bulb in the socket. In dotted lines at 24' the contact which is a resilient metal spring is shown in the bulb retained position. In this latter position the bulb contact 25 is in contact with a middle portion 26 of the contact 24 whilst an outer portion 27 of the contact is depressed toward the inner normally bottom portion 29 of the socket. On moving the lower portion to the release position the contact outer portion 27 is enabled to spring up pushing the bulb 5 out of the socket where it can be safely withdrawn from socket 3 and the fitting 1.

Also seen in Fig. 4 is a double pole switch 30 with four electrical connectors 31-34.

Connector 31 is soldered to contact 24.

Connectors 32 and 33 are connectable to the mains supply and connector 34 is connected to an electrical socket connection (not shown) in socket 3. When the switch is moved to the "off" position both connectors are isolated from the mains and no danger can ensue from someone touching either contacts in the sockets.

A further safety feature of the second socket is that when the cover member 10 is in the "bulb release" position the switch actuating member 13 is completely covered and cannot be operated even if it was able to force it past the interlock arrangement provided by the construction of the cover member.

Whilst cover member 10 neatly and advantageously slides from the "retain" to "release" position, it is possible to hinge the cover member to the second socket body at points approximate to points 50 and 51. Projection 52 on the edge of the cover member engaging with the switch actuating member 1 3 to lock the cover member in the retain position whilst the cover member could be released by the projection 52 entering a depression in area 53 to one side of the actuating member when this is in the "off" position.

Claims

Claims (filed on 25 May, 1982)

1. A tubular lamp fitting comprising two lamp sockets, a double pole switch connected to both sockets to make or break electrical power connections to the fitting, retaining means arranged to prevent removal of the lamp from the fitting and movable between a "lamp remove" position and a "lamp retain" position, the retaining means being locked against movement to the "remove position" when the switch is made in an "on" position.

2. A lamp fitting as claimed in Claim 1 wherein the retaining means interlocks with the double pole switch whereby the switch may be moved to its "on" position only when the retaining means is in the "lamp retain" position; and only when the switch is "off' may the retaining means be moved into the "lamp remove" position.

3. A lamp fitting as claimed in either Claim 1 or Claim 2 including spring means which, when the retaining means is moved to the "lamp remove" position, urges a lamp in the fitting out from one socket.

4. A lamp fitting as claimed in Claim 3 wherein the spring means acts as an electrical connection between the double pole switch and lamp bulb engaged in the socket.

5. A lamp fitting as claimed in any of the preceding claims in which the retaining means comprises a socket cover member slidable along a path substantially parallel to the axis of the bulb, the switch being located in the path of the cover member, the cover member having an interlock portion preventing movement of the cover member along the path to the "bulb release" position when the switch is in the "on" position.

6. A lamp fitting as claimed in Claim 5 in which the cover member has a slot allowing movement of the cover member along the path over the switch to the "bulb release" position when the switch is in the "off' position.

7. A lamp fitting as claimed in either Claim 5 or Claim 6 in which the switch has a manual actuating member movable across the path from the switch "on" to "off' position.

8. A lamp fitting as claimed in Claim 7 including means to prevent the manual actuating member when the switch is in the "off" position, from moving across the path during either movement of the cover member from the "bulb retain" position to the "bulb release" position or during removal of the bulb.

9. A lamp fitting substantially as described with reference to the accompanying drawings.