EP0829676A1

EP0829676A1 - Light bulb and decorative lighting system using same

Info

Publication number: EP0829676A1
Application number: EP96306671A
Authority: EP
Inventors: Calvin Chun Yin Lau
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-09-13
Filing date: 1996-09-13
Publication date: 1998-03-18

Abstract

A light bulb (1) comprising a low-voltage tungsten filament mini-light bulb (2) integrated with and substantially entirely surrounded by a moulded plastic covering (3). The base of the covering (3) is shaped as a plug (4) to be received in a corresponding socket and has electrical contacts (5) extending over its surface. A plurality of the bulbs can be electrically connected together to provide a decorative lighting system.

Description

The present invention relates to light bulbs and in particular to low voltage tungsten filament bulbs for use in decorative lighting systems.
It is known to use low voltage tungsten filament bulbs as decorative lights, such as fairy lights, both indoors and outdoors. However, conventional tungsten filament bulbs are constructed from glass and are thus comparatively fragile.
It is therefore an object of the present invention to provide a tungsten filament bulb which is more robust than conventional light bulbs.
According to a first aspect of the present invention, there is provided a light bulb comprising a tungsten filament bulb integrated with a unitary transparent or semi-transparent plastic covering which substantially entirely surrounds the tungsten filament bulb.
The light bulb of the present invention thus includes a conventional tungsten filament bulb, e.g. one having a glass outer wall, but which is surrounded by a plastic covering which forms a layer around the tungsten filament bulb which protects against shocks and impacts, and also against environmental conditions such as the weather. Thus the bulb of the present invention is more robust than conventional tungsten filament bulbs, and is therefore in particular more suitable for outdoor use.
The plastic covering is most preferably formed by moulding and can be made of any suitable transparent or semi-transparent plastic. The plastic covering can, if desired, be specially shaped and/or coloured to give a particular appearance.
The bulb of the present invention can be connected to an electricity supply by any conventional means known in the art. However, in a preferred embodiment the bulb includes electrical contacts for connection to an external electricity supply extending over at least part of the outer surface of the plastic covering. In a particularly preferred arrangement part of the plastic covering forms a plug to be received by a corresponding socket in use, and the electrical contacts are arranged to extend over at least part of the surface of the plug. The electrical contacts are preferably in the form of elongate cylinders lying on the surface of the plastic cover and having their ends embedded in the plastic cover to retain them in place.
The light bulb of the present invention is particularly suited for use in decorative lighting systems. The tungsten filament bulb is therefore preferably a low-voltage mini-light bulb.
For such decorative lighting systems a plurality of bulbs in accordance with the present invention can be electrically connected together and to means for connecting them to an electricity supply, such as a low voltage transformer, as is known in the art for conventional decorative lighting systems such as Christmas tree lights.
Thus according to a second aspect of the present invention, there is provided a decorative lighting system comprising a plurality of light bulbs in accordance with the first aspect of the present invention electrically connected to each other and to means for connecting the arrangement to an electricity supply in such a way that all the bulbs can be connected to an electricity supply simultaneously.
The bulbs are preferably electrically connected together by mounting them, preferably removably, in sockets adapted to receive the bulbs, which sockets are electrically connected to each other and to the means for connecting the arrangement to an electricity supply in such a way that they can all be connected to an electricity supply simultaneously.
The sockets can be arranged in series or parallel circuits, with the sockets and means for connecting to an electricity supply joined by appropriately arranged lengths of wire. They can be connected together in any desired arrangement, such as in a chain or in the form of a net.
The means for connecting the arrangement to an electricity supply can be, for example, a transformer or simply a plug.
An electrical connection between the bulbs and sockets can be achieved in any suitable manner known in the art. Preferably the arrangement is such that a connection is made automatically upon insertion of a bulb into a socket. In the case where the bulb has a plug including electrical contacts on its surface, the socket can have corresponding electrical contacts extending over its inner surface which contact the electrical contacts on the surface of the bulb plug when it is inserted into the socket. This arrangement enables the bulbs and sockets to be electrically connected easily and with a minimum of components for both the bulb and socket.
Preferably the plug and socket are arranged such that the plug can be inserted into the socket and then rotated, preferably by about 90°, to a position in which it is secured in the socket and the electrical contacts on the surface of the plug are in contact with the electrical contacts in the socket.
The decorative lighting system of the present invention can include further components to modify the appearance of the light bulbs. For example, different shaped and coloured covers, such as lantern-shaped covers, can be fitted over the bulbs to provide a different external appearance. The covers can be fixed to the bulbs, or can be provided as separate components to be fitted over the bulbs.
As an alternative arrangement, the bulbs can be mounted on tapering elongate cylinders to give the appearance of candlesticks. The cylinders can carry appropriate electrical connections for the bulbs. In a preferred such arrangement the cylinders are separate components which can be removably mounted on the sockets in a manner similar to the bulbs and have corresponding sockets in their other ends for receiving the light bulbs and providing an electrical connection thereto. In this candlestick arrangement, the integral plastic covering of the light bulb is preferably shaped to give the appearance of a candle flame.
The decorative lighting system can also be provided with means for connecting the light bulbs to a supporting structure. For example, crocodile clips can be removably or fixedly attached to the sockets.
The decorative lighting system of the present invention can also be provided in kit form.
Thus, according to a third aspect of the present invention, there is provided a kit for a decorative lighting system, comprising a plurality of bulbs in accordance with the first aspect of the present invention, and a plurality of sockets adapted to receive the bulbs in such a way as to form electrical connections thereto, which sockets are electrically connected to each other and to means for electrically connecting the arrangement to an electricity supply in such a way that all the sockets can be connected to an electricity supply simultaneously.
The kit can also include spare bulbs, sets of bulbs of different shapes, a number of different socket arrangements, extension leads, further components to modify the appearance of the bulbs such as the lantern coverings and candle stick components described above, and an appropriate voltage transformer. It can include adaptors and connectors to allow plural socket arrangements to be connected to the same electricity supply.
A number of preferred embodiments of the present invention will now be described by way of example only and with reference to the accompanying drawings, in which:

Figs. 1A and 1B show side views of a light bulb in accordance with the present invention;
Fig. 1C shows a cross-section along the line A-A in Fig. 1B;
Fig. 1D shows an underneath plan view of the light bulb shown in Figs. 1A, 1B and 1C;
Figs. 2, 3, 4 and 5 show examples of the light bulb of the present invention having differing external shapes;
Fig. 5A shows a top plan view of the light bulb of Fig. 5;
Fig. 6A shows a plan view of a socket for receiving the light bulbs shown in figures 1 to 5;
Fig. 6B shows a cross-section along the line A-A in Fig. 6A;
Fig. 6C shows a cross-section along the line B-B in Fig. 6B;
Fig. 7A shows a plan view of an alternative socket for receiving the light bulbs shown in figures 1 to 5;
Fig. 7B shows a cross-section along the line A-A in Fig. 7A;
Fig. 7C shows a cross-section along the line B-B in Fig. 7A;
Fig. 8 shows a plurality of light bulbs in accordance with the present invention arranged as a ten lamp lantern chain;
Fig. 9 shows in more detail the construction of the lantern lamps in Fig. 8;
Fig. 10 shows light bulbs in accordance with the present invention arranged as a fifteen lamp candle light chain;
Fig. 11 shows the construction of the candle light lamps of Fig. 10;
Fig. 12 shows in cross-section the base of the candle light lamp of Fig. 11;
Fig. 13A shows in cross-section the stick of the candle light lamp of Fig. 11;
Fig. 13B shows a cross-section along the line A-A in Fig. 13A;
Fig. 13C shows a plan view in the direction M in Fig. 13A; and
Fig. 14 shows a decorative lighting system in accordance with the present invention.

Figures 1A and 1B show side views of a light bulb in accordance with the present invention. The view shown in Figure 1B corresponds to Figure 1A rotated through 90°.
As can be seen, the light bulb 1 is a unitary structure which includes a low voltage (i.e. having a voltage rating of 3 to 36 volts and typically a power rating of 0.3 to 3 Watts) glass tungsten filament bulb 2, which is substantially entirely surrounded by and integral with a unitary transparent or semi-transparent moulded plastic covering 3. As shown in Figure 1C the covering 3 is substantially contiguous with the glass surface of the bulb 2.
The covering 3 can be moulded around the bulb by conventional moulding techniques. It can be of any type of transparent or semi-transparent plastic, and can have any desired external shape. Examples of suitable shapes for use in decorative lighting systems are shown in Figures 2-5.
At the base of the bulb 2 the plastic covering 3 is moulded to form a plug 4 which is shaped so as to cooperate with a corresponding socket (examples of which will be described in more detail below with reference to Figures 6 and 7). The plug 4 includes electrical contacts 5 which extend over the outer surface of the covering 3 in the region of the plug 4 to provide suitable contacts for connecting the bulb 2 to an electricity supply. In the embodiment illustrated the electrical contacts 5 are in the form of metal cylinders whose ends are embedded in the moulded covering 3 to fix them thereto. The cylinders are electrically connected to the filament of the bulb 2. The contacts 5 can, of course, take other forms, such as plates on the surface of the plastic covering, if desired.
The plug 4 also has flanges 6 to help to retain it in its socket.
Figures 6 and 7 show moulded plastic sockets for receiving the light bulbs of Figures 1 to 5. The sockets 10 include recesses 11 for receiving the plugs 4 of the bulbs 2. The recesses have flanges 12 which have on their inside surfaces copper terminals which engage the contacts 5 of a bulb when it is inserted in the socket to form an electrical connection between the bulb and socket. The socket terminals are connected to wires which are attached to a plug or transformer for connection to an electricity supply. The sockets can be formed by moulding them around the wires such that the wires extend as terminals along the inside surfaces of the flanges 12.
The recesses 11 and plugs 4 are shaped such that the bulbs can be inserted in one orientation and then rotated through 90° to secure them in the sockets by engagement between the flanges 6 and 12. The arrangement is also such that this rotation brings the plug contacts 5 and the socket terminals on the flanges 12 into contact to form the necessary electrical connection between the bulb and socket. The bulb can be removed by appropriate rotation in the opposite direction back to its first, insertion position.
To form a decorative lighting system a plurality of sockets in accordance with the present invention can be electrically connected together and to means for connection to an electricity supply.
One such arrangement comprising a chain of ten lantern lamps 21 connected to a transformer 22 is shown in Figure 8. Each lantern lamp 21 includes the light bulb 1 illustrated in Fig. 1 inserted in a socket 10. The sockets are electrically connected together by means of wires 23 which are connected to the transformer 22 to enable all the bulbs to be lit simultaneously. The transformer 22 can suitably be one providing, for example, a 12 volt AC output. The lamps 21 further comprise moulded plastic coverings 24 shaped to look like lanterns which are placed over the bulbs 1. Finally, each socket 10 is removably mounted on a crocodile clip 25 by a resilient push-fit arrangement to enable the lamps to be attached to appropriate supports.
Figure 9 shows in more detail the construction of the individual lamps 21 shown in Fig. 8. Firstly, a lantern cap 30 and base 31 are fitted over the light bulb 1. The lantern cap and base may be appropriately injection-moulded from suitable transparent or semi-transparent plastic material. They can be arranged to resiliently engage the bulb 1 to hold them in place.
The assembled lamp 21 is then mounted on the socket 10 by inserting the plug 4 at the base of the bulb 1 into the socket and rotating the bulb through 90° to securely mount the bulb and make the necessary electrical contact between the contacts on the plug 4 and the contact terminals in the socket 10.
Figure 10 shows an alternative decorative lighting system comprising fifteen candle light lamps 41 arranged in a chain. In this case the light bulbs 1 are as shown in Figure 4, and are supported on elongate tapering cylinders 42 which are constructed to resemble candlesticks. Cylinders 42 are mounted in sockets 10 and carry appropriate electrical connections to enable the bulbs 1 to be electrically connected to the sockets 10.
Figure 11 shows in more detail the construction of a candle lamp 41. The candlestick cylinders 42 comprise an injection-moulded plastic cylinder 51 and base 52 which can be connected together and fitted to a moulded base 53 which is constructed so as to match the plug 4 of the light bulb of the present invention, so that it can be fitted into the socket 10 in the same way. Electrical contacts 55 extend from the base 53 inside the cylinder 51 to the upper end of the cylinder 51 at which there is a socket 54 for receiving the light bulb 1 in a similar manner to the sockets 10. In this way a bulb 1 can be mounted at the top of a candlestick cylinder 42 with the appropriate electrical connections to the sockets 10 and thus to the transformer 22 still being made.
Figures 12 and 13 show in more detail the candle base 52 and candle cylinder 51, respectively.
As well as the decorative lighting systems illustrated in Figures 8 and 10, the light bulbs of the present invention can be arranged in decorative lighting systems having other configurations.
Figure 14 illustrates a number of such configurations, including an outdoor candle light chain 61 similar to that shown in Fig. 10, an outdoor lantern light chain 62 similar to that shown in Fig. 8, an outdoor tree light system 63 (which can include for example from 50 to 500 lamps), a net light system 64, and a curtain light chain system 65. In Figure 14 each system is shown being connected to a single fiveway connector ring 66 by means of plugs 67. The connector ring is additionally connected to a 12 volt transformer 22 for driving the lighting systems. The connector ring 66 is constructed with appropriate electrical connections to allow the electricity supply from the transformer 22 to be provided simultaneously to the various lighting systems 61, 62, 63, 64 and 65. Of course, alternative connector rings providing facilities to connect more or less than five lighting systems can be used, if desired, nor is it necessary to connect five systems to connector 66 at all times.
The decorative lighting system of the present invention does not have to be provided in an assembled form, and could alternatively be provided as a kit including the necessary component parts to be assembled by a user.

Claims

A light bulb (1) comprising a tungsten filament bulb (2) integrated with a unitary transparent or semi-transparent plastic covering (3) which substantially entirely surrounds the tungsten filament bulb.
The bulb of claim 1, further comprising electrical contacts (5) for the bulb extending over at least part of the outer surface of the plastic covering.
The bulb of claim 2, wherein the electrical contacts (5) are in the form of elongate cylinders lying on the surface of the plastic covering and having their ends embedded in the plastic covering.
The bulb of claim 2 or 3, wherein part of the plastic covering forms a plug (4) to be received by a corresponding socket in use, and the electrical contacts are arranged to extend over at least part of the surface of the plug.
A decorative lighting system comprising a plurality of light bulbs as claimed in claim 1, 2, 3 or 4 electrically connected to each other and to means (67) for connecting the arrangement to an electricity supply in such a way that all the bulbs can be connected to an electricity supply simultaneously.
The decorative lighting system of claim 5, wherein the bulbs (1) are mounted in sockets (10) adapted to receive the bulbs, and the sockets are electrically connected to each other and to the means for connecting the arrangement to an electricity supply in such a way that they can all be connected to an electricity supply simultaneously.
The decorative lighting system of claim 6, wherein the bulbs are removably mounted in the sockets.
The decorative lighting system of claim 5, 6 or 7, wherein the bulbs have further covers (24) fitted over them to modify their appearance.
The decorative lighting system of claim 8, wherein the further covers are lantern-shaped.
The decorative lighting system of claim 5, 6 or 7, wherein the bulbs are mounted on tapering elongate cylinders (42).
The decorative lighting system of claims 6 and 10, wherein the cylinders are removably mounted on the sockets and have corresponding sockets in their other ends for receiving the light bulbs.
The decorative lighting system of claim 10 or 11, wherein the integral plastic covering of the light bulb is shaped to give the appearance of a candle flame.
A kit for a decorative lighting system, comprising a plurality of bulbs (1) as claimed in claim 1, 2, 3 or 4, and a plurality of sockets (10) adapted to receive the bulbs in such a way as to form electrical connections thereto, which sockets are electrically connected to each other and to means for electrically connecting the arrangement to an electricity supply in such a way that all the sockets can be connected to an electricity supply simultaneously.
The kit of claim 13, further comprising a plurality of components adapted to be fitted to the bulbs or to the sockets to modify the appearance of the bulbs.
The kit of claim 14, wherein the components comprise lantern-shaped covers adapted to be fitted over the bulbs.
The kit of claim 14, wherein the components comprise tapering elongate cylinders adapted to be fitted between the bulbs and the sockets.
The kit of claim 13, 14, 15 or 16, wherein the bulbs and sockets are arranged such that an electrical connection between a bulb and socket is made automatically upon insertion of the bulb into the socket.
The kit of claim 13, 14, 15, 16 or 17, wherein each socket has electrical contacts for the bulb extending over its inner surface.
The kit of claim 18, wherein the bulbs are as claimed in claim 4, and the plugs (4) of the bulbs and the sockets (10) are arranged such that each bulb is mounted in a socket by inserting it into the socket and then rotating it by substantially 90° to a position in which it is secured in the socket and the electrical contacts (5) on the surface of the plug engage the electrical contacts on the socket.