THIS INVENTION relates to an electrical power distribution arrangement which finds application in an electrical lighting system, particularly a low voltage lighting system.

It is known to provide a continuous outlet lighting system comprising an electrical power track made of electrically insulating material and supporting a pair of electrical conductors which are electrically insulated from one another and are for connection to respective poles of an electrical power supply. Lampholders may be attached to the power track at desired locations along the track and comprise contact means for establishing electrical contacts with each of the conductors of the track in order to supply power to a lamp supported by the lampholder. Some known systems permit rotation of the lampholder about the axis of the power track in order to enable the position of the lamp to be adjusted. However, in the known systems, the degree of rotation is either restricted or electrical contact is not maintained throughout a complete revolution of the lampholder about the power track. Moreoever, the lampholders of many known systems are of complicated construction.

It is an object of the present invention to provide an electrical power distribution arrangement which is of simple construction but permits unlimited rotation or movement of a power pick-up device, such as a lampholder, about a power track of the arrangement, whilst

maintaining electrical contact between conductors of the track and terminals of the pick-up device.

Accordingly, the present invention provides an electrical power distribution arrangement comprising a power track having a non-conductive track body carrying a pair of conductor rails which are insulated from one another and are for connection to respective poles of a power supply, and a power pick-up device received on the track and rotatable about the track for positioning in a desired angular orientation, in which arrangement the pick-up device presents a pair of pick-up contacts encircling the track, an insulating spacer is non- rotatably received on the track on each side of the pick- up device, and each spacer carries a distribution contact connecting a respective conductor rail and a respective pick-up contact so as electrically to connect the pick-up contact to the conductor rail regardless of the angular orientation of the pick-up device on the track.

In one embodiment of the invention the distribution contact is resiliently compressed between the conductor rail and the pick-up contact.

In one embodiment, the track conductors are received in grooves of the track body so as to be recessed from the surface of the track body, and the distribution contacts of the spacers are engaged in the grooves so as to hold the spacers non-rot table.

In order that the invention may be more readily understood, an embodiment thereof will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a partially sectioned perspective view of the components of a low voltage track lighting

arrangement embodying the present invention; and

Figure 2 is a cross-sectional view through a lampholder of the arrangement, showing how power is supplied from the power track to terminals of the lampholder.

Referring to the drawings, a track lighting system embodying the invention comprises a power track 1 having a non-conductive body 2 formed with arcuate guide surfaces 3 and 4 and longitudinal grooves 5 and 6 separated by a web 7. The body 2 is preferably made of plastics material. Strip like copper conductor rails 8 and 9 are fixed at the bottom of the grooves 5 and 6 so as to be recessed relative to the circumscribing cylinder of the body 2, of which cylinder the guide surfaces 3 and 4 are portions. Suitable means (not shown) are provided for coupling each of the conductors 5 and 6 to a respective pole of a low voltage power source delivering ¹² volts.

Individual lengths of the power track 1 may be coupled together by suitable coupling pieces. Figure 1 shows, by way of example, a coupling piece 10 for coupling two lengths of track at right angles. The coupling piece 10 comprises a body 11 made of insulating material and presenting two hollow cylindrical spigots 12, 13 from which project respective ends of conductive coupling strips 14, 15 for engaging in the grooves 5, 6 and establishing contact with the conductor rails 8, 9.

A lampholder 20 for supporting a two-pin lamp (not shown) is made of electrically conductive material and comprises a cylindrical body 21 which is slidably and rotatably received on the track 1 on the guide surfaces 3, 4 and presents a cylindrical boss 22 extending at right angles to the axis of the cylindrical body 21. The lampholder consists of two separate radially divided

halves 20A and 20B which are fixed together with the interposition of an electrically insulating layer 23, so that the two halves are electrically isolated from each other and constitute a pair of pick-up contacts as hereinafter described. Each half of the lampholder is formed with a respective terminal socket 24A, 24B adapted to receive a respective contact pin of a lamp and to establish electrical contact with such pins. The lampholder 20 may be made of any suitable conducting material, such as brass, or may be made of an insulating material provided with suitable metal inserts forming a pair of pick-up contacts encircling the power track 1.

Lampholders 20 are located in position on the track by cylindrical spacers 30 made of insulating material and slidably received on the track 1. Spacers of various length can be provided to enable lampholders to be positioned at desired and variable locations.

Each spacer 30 is provided at each of its ends with an electrically conducting copper insert in the form of a ring 31A, 31B fixed to the spacer and carrying a power distribution contact constituted by a leaf spring 32A, 32B which projects from the end of the spacer 30. The distribution contacts 32A, 32B at opposite ends of the spacer 30 are angularly offset by 180°, so that when one contact 32A is engaged in the groove 5 of the track 1 as shown in Figure 1 , the other contact 32B is engaged in the other groove 6 of the track.

In use, a lampholder 20 is located on the power track . and is supplied with power via spacers 30 positioned on either side of the lampholder. To install a spacer 30 on the track 1 on one side of the lampholder 20, the spacer is slid onto the track 1 so that the distribution contacts 32A, 32B of the spacer 30 are engaged in the respective grooves 5 and 6 of the track 1.

The spacer 30 is then slid into position against the lampholder -20, or the lampholder is slid into position against the spacer, until the end of the spacer 30 engages the lampholder 20 and the projecting distribution contact 32A, 32B passes between the lampholder 20 and the conductor rail 8, 9 so as to be resiliently compressed

^■ between the lampholder and the conductor rail, thereby to supply power from the conductor rail 8, 9 to the associated half 20A, 20B of the lampholder 20. The spacer 30 on the other side of the lampholder 20 has its adjacent distribution contact 32B, 32A engaged in the other groove 9, 8 of the track 1 so that the other half of the lampholder is connected to the other power conductor of track 1.

In the installed position, the lampholder 20 is capable of unlimited rotational movement about the power track 1, whilst maintaining the electrical contact between the lampholder halves 20A, 20B and the respective distribution contacts 32A, 32B which, together with the spacers 30, remain stationery as a result of their engagement in the grooves 5 and 6.

Figure 1 also shows a second form of lampholder 40 for a so-called festoon lamp. This lampholder 40 comprises a cylindrical body 41 made of insulating material and having at each end an electrically conductive insert constituting a pick-up contact in the form of a ring 41 presenting an outwardly projecting radial terminal strip 42A, 42B. A festoon lamp 43 having end contacts 44A, 44B is supported between the terminal strips 42A, 42B which are supplied with power ,from respective power conductors 8, 9 of the track 1 by the distribution contacts 32A, 32B of adjacent spacers 30 in similar fashion to the lampholder 20. The lampholder 40 is similarly capable of unlimited rotational movement about the track 1 , whilst maintaining the power supply to

the lamp 43-