GB2457436A

GB2457436A - Detachably mounting fluorescent tube lighting apparatus

Info

Publication number: GB2457436A
Application number: GB0802414A
Authority: GB
Inventors: Anthony James Doyle
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-02-08
Filing date: 2008-02-08
Publication date: 2009-08-19
Also published as: GB0802414D0

Abstract

There is described a fluorescent lighting apparatus comprising a fluorescent tube and a mounting for detachably mounting the fluorescent tube. Connection means are provided for physically connecting the fluorescent tube to the mounting and electrically coupling the fluorescent tube to a ballast circuit. The connection means is arranged to secure the fluorescent tube to the mounting by insert and twist retaining means.

Description

I

FLUORESCENT LIGHTING APPARATUS

This invention relates to a fluorescent lamp. The invention has particular, but not exclusive, relevance to compact fluorescent lamps (CFLs).

A fluorescent light has an electronic or magnetic ballast coupled to a fluorescent tube. Electronic ballasts have superior properties to magnetic ballasts. The use of fluorescent lighting is more energy efficient than comparable incandescent lighting, but the cost of a fluorescent light itself is generally more expensive than a comparable incandescent light.

Generally, the lifetime of an electronic (or magnetic) ballast is longer than that of a fluorescent tube. Many fluorescent lights have a detachable tube which can be replaced at the end of its lifetime. Such fluorescent lights include linear fluorescent lights.

Integrated compact fluorescent lamps (iCFLs) are growing in popularity as a direct replacement of an incandescent light bulb. An iCFL has a fluorescent tube and integrated ballast which is connectable, for example via a conventional bayonet fitting or Edison Screw (ES) fitting, to a mains-powered lighting circuit. In this way, an incandescent light bulb can simply be replaced by an iCFL.

As a result of the need to save energy, recent legislation in the UK has stipulated that a proportion of the lights in a new building must both (i) be energy-saving (e.g. fluorescent) and (ii) of a design which prevents the owner or occupier of the building simply replacing the energy-saving light with a conventional light having a bayonet or ES fitting.

WO 2006/114577 discusses various methods of dimming an iCFL. In addition, WO 2006/114577 proposes that the fluorescent tube of a CFL may be detachable from the ballast unit. In this way, the long life of a ballast unit can be preserved by allowing for the replacement of the relatively inexpensive fluorescent tube at the end of its lifetime.

The present invention addresses improving the design of CFLs with a detachable tube.

According to the present invention there is provided a fluorescent lamp having a fluorescent tube which is detachably coupled, via a connection means, to a mounting. The connection means includes an insert-and-twist retaining mechanism. The use of such a retaining mechanism provides a secure connection between the fluorescent tube and the ballast unit without requiring a significant increase in size of the fluorescent lamp.

Preferably, the mounting comprises a plurality of electrodes for electrically connecting the fluorescent tube with a ballast unit, each electrode compnsing a pin on one of the fluorescent tube and the mounting and a socket on the other of the fluorescent tube and the mounting.

Preferably the sockets are formed on the mounting and are less than 1mm thick to prevent inadvertent insertion of a handheld connector which is more than 1mm thick.

Preferably, the connection means further comprises a key and key slot arrangement so that only a fluorescent tube with the correct properties can be electrically attached to the ballast unit. Preferably, the key and the key slot are arranged so that following insertion of the key into the key slot, rotational relative movement between the fluorescent tube and the mounting establishes electrical contact between the fluorescent tube and a ballast unit and also retains the fluorescent tube in the mounting.

Various embodiments of the invention will now be described with reference to the attached figures in which: Figure 1 is a side view of a compact fluorescent lamp having a detachable fluorescent tube; Figure 2 is a perspective view of a pair of mating members for connecting a fluorescent tube and a mounting of a compact fluorescent lamp according to the invention; Figure 3 is a plan view showing in more detail the one of the mating members illustrated in Figure 2; Figure 4 is a perspective view of a first alternative pair of mating members to the pair of mating members illustrated in Figure 2; Figure 5 is a perspective view of an alternative mating member for the pair of mating member illustrated in Figure 2; Figure 6 is an side view of a CFL fitting in which the ballast circuit is terminated by a pair of electrical terminals; Figure 7 is a side view of a CFL fitting in which the ballast circuit is terminated by a length of cable; Figure 8 is a side view of a CFL fitting in which the ballast circuit is mounted within a ceiling rose; Figure 9 is a side view of a CFL fitting within a downlight' luminaire; and Figure 10 is a side view of an alternative CFL fitting within a downlight' lurninaire.

Figure 1 schematically shows a compact fluorescent lamp 1 in which a fluorescent tube 3 is detachably mounted to one end of an elongated mounting 5. A bayonet terminal 7 is provided at the other end of the mounting 5 so that the CFL can be plugged into a conventional light fitting in place of an incandescent light bulb. In this embodiment, the mounting 5 is formed by moulded plastic.

Housed within the mounting 5 is an electronic ballast circuit formed on a printed circuit board (not shown). The electronic ballast circuit is powered by the mains power supply via the bayonet terminal 7, and supplies power to the fluorescent tube 3 in a suitable form to cause the fluorescent tube 3 to emit light. In this embodiment, the electronic ballast circuit discussed in WO 2006/114577 (the whole content of which is incorporated herein by reference) is used, which allows for dimming control of the light emitted by the fluorescent tube.

The fluorescent tube 3 is connected to the ballast circuit via an electrical plug and socket arrangement 9. In addition, the fluorescent tube 3 is secured to the mounting 5 via a physical plug and socket arrangement 11.

Embodiments of these connections will now be discussed in more detail.

Figure 2 shows an embodiment of the connecting means having a first member 21, which is connected to the fluorescent tube 3, and a second member 23, which is connected to the mounting 5.

As shown in Figure 2, the first member 21 has a circular disc shape with a key portion 25 protruding along the central axis. In this embodiment, the key portion 25 has a main cylindrical portion with two diametrically-opposed located away from the disc. A key slot 27 is formed in the second member 23 with a profile which matches the profile of the key portion 25. In this way, the key portion 25, when correctly aligned, can be inserted into the key slot 27 and then the first member can be rotated relative to the second member so that the tugs are no longer aligned with the key slot 27 and the first member 21 cannot be detached from the second member 23.

Figure 2 also shows that four electrical pins 29 are also provided on the first member 21 and provide the electrical connection to the fluorescent tube 3. The use of four electrical connections allows the electronic ballast circuit to control more easily the current through (and therefore the temperature of) the filaments contained at each end of the fluorescent tube 3.

The four electrical pins 29 are spaced so that, when the key portion 25 is aligned with the key slot 27, the four electrical pins are inserted into four electrical sockets 31 formed in the second member 23. These four electrical sockets 31 are shaped such that, after the key portion 25 has been inserted in the key slot 27, the first member 21 is still rotatable relative to the second member, i.e. the electrical sockets 31 allow rotational movement of the electrical pins 29.

In this embodiment, the width of the electrical sockets 31 (and accordingly also the electrical pins 29) is less than 1mm. This provides protection against inadvertent insertion of a conductor having a width of greater than 1mm into the mounting 5, thereby proving protection against accidental electric shocks.

As will now be described in more detail with reference to Figure 3, in this embodiment following insertion of the electrical pins 29 into the electrical sockets 31, relative rotation of the first and second members 21,23 brings the electrical pins 29 into contact with respective electrical contacts to the ballast circuit. In particular, in this embodiment these electrical contacts are formed by leaf springs 41.

The leaf springs 41 are constrained within the second member 23 so that following insertion of the electrical pins 29 into the electrical sockets 31 and twisting of the first member 21 relative to the second member 23, each electrical pin 29 is gripped between a contact portion of a corresponding leaf spring 41 and the body of the second member 23.

Modifications and Further Embodiments It will be appreciated that the shape of the key portion/key slot could be varied. For example, as shown in Figure 4, an alternative key portion 51 has a central cylindrical portion with three lugs circumferentially spaced at 90° intervals and located away from the disc portion of the first member, with a matching key slot 53 formed in the second member. It will be noted that the lugs in the embodiment illustrated in Figure 4 do not protrude as far from the central cylindrical portion as those in the embodiment illustrated in Figures 2 and 3.

In a preferred embodiment, different key portions are used for different types of fluorescent tube and the key slot provided on a mounting only allows fluorescent tubes which can be used with the ballast circuit housed within the mounting to be connected.

Some electronic ballasts can work with a range of fluorescent tubes. It will be appreciated that by suitable design of the key portions, a key slot can be provided which will accept more than one type of key portion. For example, Figure 5 shows a second member having a key slot 61 which will accept both the key portion illustrated in Figure 2 and the key portion illustrated in Figure 4.

In the embodiment illustrated in Figures 2 and 3, electrical contact between the fluorescent tube and the ballast circuit is provided via leaf springs which are biased in the direction of the electrical pins in order to maintain a good connection. Alternatively, the electrical contact could be pieces of metal which are held in a position in the mounting such that respective helical springs push the pieces of metal into contact with the electrical pins to maintain a firm contact.

In the previous embodiments, the ballast circuit is terminated by a bayonet-type electrical terminal, so that the CFL can be directly connected to the mains-powered lighting circuit. Other types of electrical terminal could be used to terminate the ballast circuit, for example an Edison Screw (ES) electrical terminal. Those skilled in the art will appreciate that there are in fact tow sizes of bayonet fitting and three sizes of Edison Screw termination (E14, E27 and E26) commonly in use.

Using a bayonet-type or ES-type electrical terminal allows the CFL to replace a conventional incandescent light bulb, and vice versa. However, it is sometimes desired to prevent an energy-saving CFL from being replaced by a conventional incandescent light bulb. This could be done by hard-wiring' the ballast circuit to the mains-powered lighting circuit. For example, Figure 6 shows a fitting in which ballast circuit I terminated by screw or push-in terminals which receive the two wires of a lighting circuit emerging from the ceiling in the manner of a conventional lamp holder. Alternatively, Figure 7 shows a fitting in which the ballast circuit is terminated by a length of wire cable which emerges from the housing of the ballast circuit and can be attached directly to a ceiling fitting. As shown in Figure 8, as another alternative the ballast circuit could actually be housed in a ceiling rose which is connected to a fluorescent tube mounting via a cable.

In another embodiment, the detachable fluorescent tube arrangement is incorporated into a luniinaire of the type commonly called a "downlight".

This type of light fitting is fitted into a hole in a ceiling so that only the light-emitting element, generally with a decorative surround, is visible from the room below the ceiling. Any other parts of the luminaire, which may include electrical control equipment, are hidden from view above the lower surface of the ceiling. By using the invention, the fluorescent tube can be easily detached from the luminaire for replacement without removing the luminaire from the ceiling. Figures 9 and 10 show embodiments of such downlight' luminaires.

Although the above embodiments utilise electronic ballast circuits such as described in WO 2006/114577, this is not essential. For example, a non-dimming ballast circuit could be used. Also, it is not essential to provide four electrical connections between the ballast circuit and the fluorescent tube.

For example, two electrical connections could be used.

In the illustrated embodiments, electrical pins fixed relative to the fluorescent tube are inserted into slots in the mounting. It will be appreciated that one or more electrical pins could be provided on the housing and inserted into slots fixed relative to the fluorescent tube. But this is not preferred due to the increased risk of electrical shock.

It will also be appreciated that the key portion could be provided on the mounting and the key slot provided on the fluorescent tube.

Claims

CLAIMSI. A fluorescent lighting apparatus comprising: a fluorescent tube; and a mounting for detachably mounting the fluorescent tube via connection means for physically connecting the fluorescent tube to the mounting and electrically coupling the fluorescent tube to a ballast circuit, wherein the connection means is arranged to secure the fluorescent tube to the mounting by insert and twist retaining means.
2. A fluorescent lighting apparatus according to claim 1, wherein said connecting means comprises a plurality of electrical connection means for electrically coupling the fluorescent tube to the ballast circuit, each electrical connection means comprising a pin on one of the fluorescent tube and the mounting and a slot on the other of the fluorescent tube and the mounting for receiving the associated pin.
3. A fluorescent lighting apparatus according to claim 2, wherein the thickness of the slot is less than 1mm.
4. A fluorescent lighting apparatus according to claim 2 or 3, wherein all the pins are provided on the fluorescent tube.
5. A fluorescent lighting apparatus according to any of claims 2 to 4, wherein the electrical connection means comprises four pin-and-slot pairs.
6. A fluorescent lighting apparatus according to any of claims 2 to 5, wherein following insertion of the pins into the associated sockets, relative rotational movement of the fluorescent tube and the mounting establishes a secure connection between the pin and an electrical contact for connecting to the ballast circuit.
7. A fluorescent lighting apparatus according to claim 6, further comprising a biasing means for biasing said electrical contact into connection with an associated electrical pin to establish said secure connection.
8. A fluorescent lighting apparatus according to claim 7, wherein said biasing means comprises a leaf spring.
9. A fluorescent lighting apparatus according to claim 7, wherein said biasing means comprises a helical spring.
10. A fluorescent lighting apparatus according to any preceding claim, wherein the connection means comprises key means provided on one of the fluorescent tube and the mounting and key socket means provided on the other of the fluorescent tube and the mounting.
11. A fluorescent lighting apparatus according to claim 10, wherein the key means is provided on the fluorescent tube and is indicative of the electrical properties of the fluorescent tube, and the key socket means is provided on the mounting and is indicative of the ballast circuit associated with the housing.
12. A fluorescent lighting apparatus according to claim 11, wherein the key socket means is arranged to accept any one of a plurality of key means which are each for a fluorescent tube which is compatible with the ballast circuit.
13. A fluorescent lighting apparatus according to any preceding claim, further comprising said ballast circuit.
14. A fluorescent lighting apparatus according to claim 13, wherein the ballast circuit is housed within a housing comprising said mounting.
15. A fluorescent lighting apparatus according to claim 14, wherein the ballast circuit is terminated by a bayonet or Edison screw electrical terminal.
16. A fluorescent lighting apparatus according to claim 14, wherein the ballast circuit is terminated by a pair of terminals for receiving a pair of wires.
17. A fluorescent lighting apparatus according to claim 14, wherein the ballast circuit is terminated by a cable.
18. A fluorescent lighting apparatus according to claim 13, wherein the ballast circuit is mounted in a ceiling rose.
19. A downlight comprising a fluorescent lighting apparatus as claimed in any preceding claim.