GB2229585A

GB2229585A - Coupling for an electric distribution track

Info

Publication number: GB2229585A
Application number: GB8906740A
Authority: GB
Inventors: Terence Alan Woodgate
Original assignee: Rotaflex Ltd; GTE Rotaflex Ltd
Current assignee: Rotaflex Ltd; GTE Rotaflex Ltd
Priority date: 1989-03-23
Filing date: 1989-03-23
Publication date: 1990-09-26
Anticipated expiration: 2009-03-23
Also published as: GB8906740D0; GB2229585B; EP0609917A2; EP0609917A3

Abstract

A coupling for an electric distribution track includes a track (1) with a channel having an inner wall carrying a conductor (10) and side walls (6, 7) with inturned flanges (8, 9), an elongate connector rod (2) with a screw threaded end through which a contact (16) projects and a nut (18) which engages behind the flanges and presses the end of the connector and the contact against the track conductor. <IMAGE>

Description

ELECTRIC COUPLING This invention relates to electrical assemblies, and in particular it concerns a coupling for an electric distribution track. The coupling of the invention is suitable for supplying electric current to a track and/or taking current off from the track for supply to an appliance or another track section.

Electric distribution tracks are well known and generally comprise elongate channels along which.

elongate conducts extend. A supply connector is fitted to the track channel, most frequently at one end of a track length, for connecting the track to a source of electric power. Other connectors, commonly known as "adaptors", can be engaged with the track at any position along its length for connecting electric appliances, usually but not necessarily light fittings, to the track. The adaptors are designed to provide mechanical support for the light fittings, so that they are supported by the track. The most common arrangement is for a track to be supported below a ceiling and for the light fittings to be suspended beneath the track, but other arrangements are possible. By tradition the supply connectors and adaptors tend to be of different constructions in view of their differing duties, although they do fit together with the same track.Hitherto supply connectors and adaptors have been of relatively complicated designs with bodies of insulating material carrying contacts for engagement with the track conductors and means to ensure mechanical securement with the track channel. In recent years there has been a trend towards low voltage track lighting systems and in some cases the channel configuration for the track has been abandoned, which has been made possible because the need for the conductors to be concealed is removed as there are no shock hazards with low voltage systems. Nonetheless, the supply connectors and adaptors have remained of relatively complicated construction.

The present invention provides an electric track coupling of elegantly simple yet highly effective design for a low voltage distribution system. A coupling embodying the invention comprises a track length including a member defining a channel with an inner wall and two side walls having means defining inwardly facing abutment shoulders extending along the channel, a conductor extending along and supported by the inner wall, a connector having a screw threaded tubular part, a contact pin projecting through the tubular part, and a thread element received in the track channel in engagement with the abutment shoulders, said element having threaded engagement with the tubular part and causing the contact pin to be pressed into firm engagement with the track conductor. It will be appreciated that such a coupling requires a minimum number of components and each is of uncomplicated design.

A better understanding of the invention will be had from the following detailed description given with reference to the accompanying drawings, in which: Figure 1 is an end view of a coupling embodying the invention; Figure 2 is a side view of the coupling with the track shown partly in cross-section; and Figure 3 is a top plan view of the coupling.

The electrical coupling shown in the drawings forms part of a low voltage distribution system including a length of track 1, a member 2 for supplying electric current to the track and supporting the track, e.g. from a ceiling, and a similar member 3 for connecting a light fitting, or other appliance, both electrically and mechanically to the track so that it is supported by and powered from the track. The track 1 is of double channel configuration and shaped symmetrically with respect to a medial, horizontal plane.

Each channel includes an inner end wall formed by a transverse web 5, and a pair of opposed side walls 6, 7 each of which is undercut to form inturned lips or flanges 8, 9 at the sides of the channel mouth.

Supported on the inner wall of the channel and electrically isolated therefrom by a strip 12 of insulating material is a conductor 10. The track is of uniform cross section along its length and at a convenient location, such as at one end, the two conductors 10 are connected together by a bridging element extending through or around the edge of the web 5. The main body of the track is conductive, e.g. made of aluminium and serves as the second conductor of the track for transmitting electric power.

Each member 2, 3 may consist of a rigid conductor rod as described in our application being filed on the same day and claiming priority from earlier application no. 8814581.8, at a rotation joint as also described in the same said concommittently filed application. Projecting at the end of the member 2, 3 is an externally threaded tubular part or sleeve 15 which also constitutes a first contact. A second contact is provided by an axial pin 16 projecting through and beyond the sleeve 15 to make contact with the track conductor 10. The pin 16 is spaced from the outer contact 15 by an insulating sleeve 17 which has an enlarged head at its outer end in abutment with the end of the contact 15. The pin 16 is spring loaded and normally projects a little beyond the end of the insulator sleeve 17.Screwed onto the threaded contact 15 is a square nut 18 which on both sides and on all four edges is rebated to define a central land on each side. The land is dimensioned to be received non-rotatably between the track lips 8, 9 while the shoulder surfaces at opposite edges of the nut engage the abutment shoulders defined by the lips. It will be appreciated that the shape of the nut means that it can be inverted and fitted either way round in the track, whereby correct assembly of the coupling is facilitated.

With the nut unscrewed to the edge of the contact 15, the nut can be introduced into the track channel by a tilting movement of the member 2, 3. The member 2, 3 is then rotated so that the nut 18 is driven into firm abutment with the track lips 8, 9 while the reaction force acts to clamp the insulator 17 against the conductor 10. The pin contact 16 retracting due to its spring loading but still being pressed against the conductor 10. Consequently, the outer contact 15 is connected to the main body of the track through the nut 18, and the pin 16 connects directly to the conductor 10, good contact pressure being ensured in both cases by the clamping action produced by the threaded connection of the nut on the contact 15.

The clamping action secures the conductor rod 2, 3 rigidly to the track with the rod extending at right angles from the track so that firm support is ensured either from the track itself when carried by the rod 2 or for an electric appliance when carried from the track on the rod 3.

The described electrical coupling is of simple construction, but it is also easy to assemble and is effective in use. In addition it can be used for both current supply and take-off connections. Furthermore, all the connection parts are housed within the track channel so that the visual appearance is improved.

It should be understood that in an electrical distribution system the or each track member 1 may be carried by two or more supporting rods 2 spaced apart along the track member, but not all of these supporting rods are necessarily used for current supply purposes.

Claims

CLAIMS:-

1. A coupling for a low voltage electric distribution system, comprising an elongate track member defining a channel with an inner wall and opposed side walls having means defining inwardly facing abutment surfaces, a conductor extending along the channel and supported by the inner wall, a connector including a screw threaded part and a contact projecting therethrough for contacting the track conductor, and a clamping element received in the channel and in screw threaded engagement with said connector part, the element abutting said abutment surfaces and the reaction force acting thereon causing the contact to be pressed into engagement with the conductor.

2. A coupling according to claim 1, wherein said reaction force on the element acts to cause the end of the screw threaded part of the connector to press against the inner wall of the channel.

3. A coupling according to claim 2, wherein an insulator is interposed between the contact and the threaded connector part, and the connector part presses against the inner wall through the insulator and the conductor.

4. A coupling according to claim 1, 2 or 3, wherein the track member constitutes a second track conductor, the screw threaded connector part constitutes a second contact, and the element acts to connect electrically the said second contact to the track member.

5. A coupling according to any of claims 1 to 4, wherein the connector part is externally screw threaded and the element is a nut.

6. A coupling according to claim 5, wherein the nut is non-rotatable in the channel.

7. A coupling according to claim 6 wherein the nut has means engageable in the channel mouth to prevent rotation of the nut.

8. A coupling according to claim 5, 6 or 7, wherein the nut is square.

9. A coupling according to claim 5, 6 or 7 wherein the nut can be introduced into the channel through the channel mouth and then moved into engagement with the abutment surfaces.

10. A coupling according to claim 7, wherein the nut is insertable into the channel when loosened but still screwed on the threaded connector part.

11. A coupling according to any one of claims 1 to 6, wherein the abutment surfaces are defined by inturned lips on the side walls of the channel.

12. A coupling according to any one of the preceding claims wherein the connector is elongated and stiff, and the said clamping action secures the connector rigidly to the track and substantially perpendicular thereto.

13. A electric coupling substantially as herein described with reference to the accompanying drawings.

14. A coupling according to any one of the preceding claims wherein the track member is of double channel form and the connector is engageable in either channel to support mechanically the track from either above or below and to supply electric current to the track.