GB2153986A

GB2153986A - Improvements in lamps and lamp holders for display lighting

Info

Publication number: GB2153986A
Application number: GB08403648A
Authority: GB
Inventors: Alex Leopold Halberstadt; David Wynne Parlour
Original assignee: Thorn EMI PLC
Current assignee: EMI Group Ltd
Priority date: 1984-02-11
Filing date: 1984-02-11
Publication date: 1985-08-29
Also published as: GB8403648D0; GB2153986B; DE8501678U1

Abstract

The lamp assembly comprises a bi-pin reflector lamp 21 and a lamp holder 22 in which the reflector lamp is end mounted to the lamp holder by clips. The lamp has location devices on the reflector stem which can engage with the clips 24. The location devices are preferably grooves 35 engaging with spring arms. <IMAGE>

Description

SPECIFICATION Improvements in lamps and lamp holders for display lighting This invention relates to lamp assemblies, primarily, but not exclusively for display lighting purposes. A typical lamp assembly 10 for such display lighting purposes is shown in Fig. 1. This comprises a bi-pin reflector lamp 11 complete with bulb 1 2 set permanently within a reflector 1 3 by a suitable heat resisting cement.The mirror lamp 11 is held within a shallow U-shaped bracket or lamp holder 1 4 where one leg of the U comprises a front bracket portion 1 5 with attached spring arms 1 6 to act on and hold the rim of the reflector 1 3 while the terminal pins 1 7 projecting from the stem lamp 1 8 fit within slots 1 9 in insulator portion 20 which forms the other leg of the U shape. Thus it can be appreciated that the lamp 11 is held securely within the holder 14 no matter what the orientation of the holder is.This arrangement, however, for some displaying purposes is aesthetically unpleasing and it would be an improvement to dispense with the front bracket portion 1 5 and have the reflector lamp 11 held completely only by an end mounting. However, with this arrangement, in some positions, for example in the vertical position, the lamp may not be sufficiently securely held by the terminal pins. An alternative which solves this problem and provides for end mounting is to employ a reflector lamp with a standard bayonet cap fitted (SBC). However, because of the high temperatures which can be generated in the lamp stem which can be as high as 250"C it is necessary to use a suitable refractory cement to retain the SBC on the stem and this amount can increase the manufacturing cost of the lamp.Because of these temperature considerations such a lamp would be limited to 50 watt power rating. Moreover it will be appreciated that, for lamps produced in large volume such as those under discussion, the reflector is, in fact, a moulding which has been found the most economical method of contructing this item.

An object of this invention is to provide an end mounted lamp assembly for display purposes, as an alternative to an SBC lamp, said lamp having a power rating of up to and more than 70 watts.

According to the invention there is provided a lamp assembly for display lighting the assembly comprising a moulded mirror lamp having a reflector with a tapered stem and two terminal pins projecting from the stem and a lamp bulb secured within the reflector, the reflector in use, being co-operable with a lamp holder receiving the terminal pins characterised in that the reflector lamp is end mounted to the lamp holder by a clip or clips on the lamp holder engaging with a location device or devices on the tapered stem.

The clips may be spring arms. The location device is prefeably an indentation, such as a dimple or preferably a groove.

The invention will now be described by way of example only and with reference to the accompanying drawings wherein: Figure 1 is a perspective view of a prior art lamp assembly as discussed hereinbefore, Figure 2 is a perspective view of a lamp and lamp holder according to the invention (unassembled), Figure 3 is an end elevation of a lamp holder according to the invention (assembled) and, Figure 4 is a side elevation of the lamp and lamp holder of Fig. 3.

In Fig. 2 a lamp assembly according to one aspect of the invention comprises a reflector lamp 21 which is used in conjunction with lamp holder 22. Lamp holder 22 comprises an annular base 23 of ceramic or other suitable material carrying outstanding spring arms 24 which include flange portions 25. Retainers 26 fasten the flange portions 25 to base 23. Spring arms 24 are made of resilient material which retains its resiliency at the working temperature of around 250"C one such material being perma nickel. Spring arms 24 have kinked portions 27 forming ridges or locating devices across the width of the arm 24 adjacent each free end 28. A guide 29 is formed on one free end 28. An electrical connection is made internally of the annular base 23 which connects lead wires 30 to terminal receptacles 31.Reflector lamp 21 has a bulb 32 set into the reflector 33 and includes a stem portion 34 of rectangular cross section. The stem 34 has a groove 35 formed across each major or long side 38 to provide a locating device complementary to the ridges in pins 24. Terminal pins 36 protrude from the bottom pat 37 of stem 34. As stated previously, for reasons of economy it is desirable to make the mirror lamp from a moulding and to facilitate this it is necessary to form the stem with a draft taper to make for easy removal from the mould. This taper is shown in Figs. 3 and 4 to be approximately 3" on all four sides.

The mirror lamp 21 is used in conjunction with the lamp holder 22 and as best seen in Fig. 3 the ridged portions 27 of spring arms 24 locate within the corresponding grooves 35 formed in the major or long sides 38 of stem 34. Consequently reflector lamp 21 will be securely held and located between spring arms 24. Thus the lamp assembly can be conveniently end mounted by means of attaching base 23 to a suitable fitting indicated at 39 as shown in Figs. 3 and 4. It is envisaged the invention could encompass a mirror lamp with a tapered but circular cross section stem and in this case the spring arms could be of wire and shaped to encompass partially the single groove formed in the tapered stem. However, because it is preferred not to employ a split mould the groove or grooves as the case may be. on the tapered stem should be a depression. If the mirror lamp is to be other than a moulding the grooves 35 can be replaced by dimples or locating devices with appropriate changes to the clips 24. Only one groove could be used co-operating with a ridge 27 on spring arm 24. This reduces the amount of work to be done on the stem 34.

Claims

1. A lamp assembly comprising a mirror lamp having a reflector with a stem, two terminal pins projecting from the stem, a lamp bulb secured within the reflector, and a lamp holder receiving the terminal pins to locate the mirror lamp therein characterised in that the reflector lamp is end mounted to the lamp holder by a clip or clips on the lamp holder engaging with a location device or devices on the stem.

2. A lamp assembly according to Claim 1 in which the clips are spring arms.

3. A lamp assembly according to Claim 1 or Claim 2 in which the location device is an indentation.

4. A lamp assembly according to Claim 3 in which the indentation is a groove.

5. A lamp assembly according to Claim 3 in which the indentation is a dimple.

6. A lamp assembly substantially as herein described with reference to Figs. 2, 3 and 4 of the accompanying drawings.

7. A mirror lamp having a reflector with a stem, two terminal pins projecting from the stem and a lamp bulb secured within the reflector characterised in that the reflector is provided with one or more location devices on the stem for co-operation with one or more clips on a lamp holder in which the lamp is to be inserted in use.

8. A mirror lamp according to Claim 7 in which the location device is an indentation.

9. A mirror lamp according to Claim 8 in which the indentation is a groove.

10. A mirror lamp substantially as herein described with reference to Figs. 2, 3 and 4 of the accompanying drawings.