GB2228789A

GB2228789A - Translucent sleeve for fluorescent lamp

Info

Publication number: GB2228789A
Application number: GB8904763A
Authority: GB
Inventors: Raymond G Banton
Original assignee: AG Patents Ltd
Current assignee: AG Patents Ltd
Priority date: 1989-03-02
Filing date: 1989-03-02
Publication date: 1990-09-05
Anticipated expiration: 2009-03-02
Also published as: GB2228789B; GB8904763D0

Abstract

A translucent sleeve 1 is formed from a lightweight plastics material and adapted for push-fit engagement with compact low energy lamps 4 of the type having a looped fluorescent tube 3 having a single base unit 5 incorporating electrical connections 6 for the supply of electrical power to both ends of the tube 3. The sleeve 1 provides the lamp 4 with an improved or distinctive appearance and can be single or multi-coloured, lantern shaped or shaped like a traditional bulb or candle flame. The lower open end of the sleeve 1 defines a skirt portion 2 which is shaped to engage resiliently around the lower part of the tube 3 and/or over the base unit 5 of the lamp 4. <IMAGE>

Description

Improvements relating to lightinq This invention relates to lighting.

Fluorescent i.e. gas discharge tubes are well known as a source of illumination and have the advantage of high lighting efficiency combined with low energy consumption as compared with traditional incandescent light bulbs. Traditional fluorescent tubes are provided with an electrical contact at each end arranged for engagement with corresponding longitudinally spaced connectors of an elongate wall or ceiling mounted fitting so that the tube is replaceably mountable to such fitting. The fitting generally includes a "starter" unit for energising the tube when the lamp is switched on.

There have also more recently been produced compact low energy lamps which comprise a looped fluorescent tube having a single base unit incorporating electrical connectors for the supply of electrical power to both ends of the tube. The base unft is in turn provided with suitable connecting means whereby the lamp can be interchangeably engaged with a suitable light fitting. The starter unit for the tube may form part of the base unit itself or part of the light fitting.

The connecting means may vary, and could comprise a bayonet type fitting or screw type fitting of a sort similar to those used with traditional incandescent lamps, or, alternatively, spaced contact pins of the base unit may be arranged for engagement with complementary female contacts of a corresponding socket connector. Low energy lamps having the latter form of connecting means are presently commercially available under the trade mark "Wotan Dulux D" from Maxilux Interna and examples of such lamps are described in European Patent Specification No. 0156291 and British Patent Specification No. 2077488. Lamps of this general type, i.e. those having a looped fluorescent tube and a base unit at one end, are hereinafter called "compact low energy lamps of the kind described".

Low energy lamps of this type have the major advantage that they can be used in place of traditional incandescent light bulbs but consume substantially less power to produce the same brightness. Thus, a 9 watt low energy lamp produces comparable lumination to a 40W traditional bulb whilst a 25W low energy lamp is comparable to a 100W traditional bulb.

It has now been recognised, however, that a drawback of compact low energy lamps of the kind described is that their appearance is not particularly pleasing to the eye insofar as the loop or loops of fluorescent tube are unattractive. Previously, therefore, such lamps have only generally been used in conjunctibn with lamp shades which shield the lamps themselves from the eye.

Viewed from one aspect the invention-provides a compact low energy lamp of the kind described in combination with a transluscent sleeve formed of a lightweight plastics material and adapted to be located over the fluorescent tube of the lamp by push fit engagement therewith to provide the lamp with an improved or distinctive appearance.

Viewed from a second aspect the invention provides a transluscent sleeve formed of a lightweight plastics material and adapted for push-fit engagement with a compact low energy lamp of the kind described to provide the lamp with an improved or distinctive appearance.

Thus, in accordance with the invention a low energy lamp may be conveniently and inexpensively adapted for use as a "feature" lamp i.e. one where the lamp is intended to be directly visible. Common examples of feature lamps are those resembling candles which are particularly popular in establishments such as hotels, restaurants, public houses etc.

and which have previously constituted incandescent bulbs. In accordance with the invention such bulbs may be replaced with low energy consumption lamps fitted with plastic sleeves which for such applications are preferably plain white opaque and shaped to resemble a candle flame. The sleeves being inexpensive to manufacture do not significantly increase the overall cost of the lamps, which in the long term.

provide substantial savings as compared with incandescent bulbs owing to the lower energy requirements particularly in the case of a commercial establishment having numerous candle type lamps.

The sleeves may however have any number of the other decorative appearances depending on the application concerned, and might for example be single or multi-coloured, lantern shape, or shaped like a traditional bulb. In accordance with the invention, therefore, low energy lamps may be adapted for other decorative purposes previously asociated only with incandescent bulbs such as lamps for Christmas decorations or for adorning the outside of buildings, bridges etc., with resulting energy savings.

In a preferred embodiment the decorative sleeve is detachably engaged with the lamp so that sleeves can be exchanged from one lamp to another when a lamp eventually fails and that, for example, lamps may optionally be supplied with a variety of sleeves of different colours, shapes, etc.

to enable the user to select a desired combination for a particular decorative purpose. The sleeves for a particular type of lamp could also be sold separately as an inexpensive conversion pack for decorative purposes.

The sleeve may be adapted closely to surround the looped fluorescent tube and is advantageously arranged for resilient engagement directly with the tube in the region thereof adjacent the base unit when the sleeve is push-fitted over the tube. Additionally or alternatively the sleeve may be adapted to be resiliently engaged with part of the base unit of the lamp, which traditionally includes a ceramic housing enclosing the electrical components. Thus, the lower open end of the sleeve preferably defines a skirt portion which is so shaped to engage resiliently around the lower part of the tube and/or over part of the base unit of the lamp when the sleeve is push-fitted onto the lamp with sufficient firmness at least to prevent the sleeve becoming detached from the lamp under its own weight.It will be appreciated that the use of a plastics sleeve directly engaging in part and in close proximity with the tube and base unit is possible since the operating temperature of such a tube is very substantially lower than that of a traditional incandescent bulb. The sleeves in accordance with the invention may conveniently be formed from any suitable plastics material by any convenient method. For example, such sleeves may be formed of perspex by vacuum moulding, or from PET plastic by blow moulding.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, wherein: Figure 1 is a schematic side elevation of a first embodiment of plastics sleeve; Figure 2 is an underside plan view of the sleeve shown in Figure 1; Figure 3 is a schematic side elevation of the sleeve engaged with a compact low energy lamp of the kind described; and Figures 4,5 and 6 are views similar to Figures 1 to 3 but illustrating a second embodiment of plastics sleeve.

Referring to the drawings, a candle flameshaped sleeve 1 is e.g. vacuum moulded from light opal perspex and includes at its lower open end a skirt portion 2 which is so-shaped in cross-section (see Figure 2) to fit snugly over and resiliently engage the looped fluorescent tube 3 of a compact low energy lamp 4 of the kind described, as shown in Figure 3. The lamp 4 may be of a type commercially available under the trade mark Wotan Dulux D and includes a base unit 5 having downwardly projecting pins 6 adapted to make electrical connection with female contacts of an associated socket connector (not shown) whereby electrical power is supplied to respective ends of the tube 3.In the illustrated embodiment the tube 3 has a double looped configuration, and therefore defines a generally square crosssection with rounded corners when viewed from above, the shape of which is matched by the cross-section of the skirt portion 2 of the sleeve 1 as shown in Figure 2. As mentioned above the colour and shape of the sleeve 1 may vary having regard to the application concerned.

Figures 4 to 6 illustrate a second embodiment of plastics sleeve 1, which is shaped to resemble a traditional incandescent light bulb. The sleeve of this embodiment also differs from the first embodiment in that the skirt portion 2 is adapted to resiliently engage over part of the ceramic housing of the base unit 5 when the sleeve is push fitted onto the lamp. This improves the firmness of engagement of the sleeve, and this alternative mounting arrangement may of course also be applied to candle flame shaped sleeves such as shown in Figures 1 to 3 if desired.

Claims

CLAIMS:

1. A transluscent sleeve formed of a lightweight plastics material and adapted for push-fit engagement with a compact low energy lamp of the kind described to provide the lamp with an improved or distinctive appearance.

2. A transluscent sleeve as claimed in claim 1 wherein the sleeve is detachably engaged with the lamp.

3. A transluscent sleeve as claimed in claim 1 or claim 2 wherein the lower open end of the sleeve defines a skirt portion which is so shaped to engage resiliently around the lower part of the tube and/or over part of the base unit of the lamp with sufficient firmness at least to prevent the sleeve becoming detached from the lamp under its own weight.

4. A transluscent sleeve as claimed in claims 1, 2 or 3 wherein the sleeve is plain white opaque and shaped to resemble a candle flame.

5. A transluscent sleeve as claimed in claims 1, 2 or 3 wherein the sleeve is single or multi-coloured, lantern shaped, or shaped like a traditional bulb.

6. A transluscent sleeve as claimed in any preceding claim wherein the sleeve is formed of perspex by vacuum moulding or from PET plastic by blow moulding.

7. A transluscent sleeve substantially as hereinbefore described with reference to Figures 1-3 of the accompanying drawings.

8. A transluscent sleeve substantially as hereinbefore described with reference to Figures 4-6 of the accompanying drawings.

9. A compact low energy lamp of the kind described in combination with a transluscent sleeve of any preceding claim.