GB2115235A - Track for electrical devices - Google Patents

Abstract

A track for supporting electrical devices such as lights comprises a channel (1) having side grooves (11) containing wires for feeding current to connectors which may be inserted in the channel at any point along it and rotated so that tongues (35) on the connector make contact with the wires to establish a circuit. The connectors may be locked in the channel by rotatable pegs. <IMAGE>

Description

SPECIFICATION Track for electric devices This invention relates to a'track on which may be mounted electric devices such as, for example, lamp holders at any desired position along the track for connection to an electrical power source.

According to one aspect of the invention, there is provided a track for supporting electrical devices comprising an elongate channel member of substantially uniform cross-section of electrically insulating material having a plurality of longitudinal grooves, each groove opening into the interior of the channel from a side wall,and at least two of the grooves containing an exposed wire extending along the groove for connection to an electric circuit, and engageable by a connector extending into the groove from within the channel.

A boss may support an electric lamp holder or other device which is to be fed with current from the wires and may be inserted and rotated to engage the wires at any point along the track. A plurality of bosses may be inserted at different position5 along the track so that several devices may be fed with current from the same wires.

In general one of the two wires will be the live wire and the other the neutral wire of a circuit. A third wire, contained in a third groove, may serve as an earth wire and engage a third tongue projecting from the boss. In a preferred arrangement the live and earth wires are positioned in grooves in one wall ofthe channel and the neutral in a groove in the opposite wall. The neutral and live wires may be in diametrically opposed grooves.

If desired, more than one pair of live and neutral wires may be arranged in respective pairs of grooves so that the device carried by the boss may be connected to alternative circuits, depending on the positions of the tongues on the boss. In a preferred arrangement both of the walls of the channel are provided with three grooves, one groove nearest the opening ofthe channel contains an earth wire and pairs of diametrically opposed grooves remote from the opening contain respective pairs of live and neutral wires.

The wires are generally positioned at the bottom of the grooves and the grooves should be sufficiently narrow and deep to avoid significant risk of accidental contact between a wire and a finger, screwdriver blade or the like inserted in the channel.

The wires at the bottoms of the grooves may be surrounded by the insulating material of the track through an angle of more than 1 80" to hold the wires in place. The thickness of the wires is preferably at least 2 mm to provide an adequate area of contact between the wire and a tongue of the boss.

The body of the track is made of an electrically insulating material which may be a plastics material such as polyvinylchloride; the track may generally be formed by extrusion.

The stiffness of the track may be increased by incorporating a longitudinal support of metal, advantageously aluminium, in the track.

The bottom of the channel may be provided with holes to facilitate mounting of the track on a ceiling or other support surface by screws passing through the holes.

The track may be provided with a snap-on lid to close the channel when the bosses have been inserted in the desired positions.

The wires in the grooves may be connected to a power supply by a terminal end fitting engaging an end of the track. The end fitting may comprise an enclosure containing terminals to be connected to a power supply and a plug moulding dimensioned to slide into the channel of the track from the open track end. The plug moulding may be provided with outwardly projecting tongues to slide into the grooves of the track and establish electrical contact with the wires, the tongues being connected to the terminals in the enclosure. The end fitting may also be provided with a tab connected to earth to establish an earth connection with the metal reinforcing support, if required.

The boss may be provided with a locating projection positioned to enter a groove of the channel which does not contain a wire, in order to locate the boss correctly relative to the other grooves. The boss is generally attached to an assembly for supporting the lamp or other device and this assembly may be provided with one or more locking devices for locking the assembly in place when it is installed on the track. The locking device may comprise a rotatable peg having a foot which can extend into the channel, the foot being shaped so that on rotation it can abut opposite inside surfaces of the channel to retain the assembly in position by friction.

A track assembly according to an embodiment of the invention will be described by way of example with reference to the accompanying drawings, in which: Figure 1 is an exploded view of a track with an end stop, terminal end fitting and lids for the track and fitting, Figure 2 is a cross-section of a track and lid similar to those shown in Figure 1, Figure 3 is an elevation of a plug moulding forming part of the terminal end fitting of Figure 1, Figure 4 is an elevation perpendicular to that of Figure 3 of a plug moulding similar to that of Figure 3 for use with the track of Figure 2.

Figure 5 is a cross-section of a lamp holder for use with the track of Figure 1 or 2, Figure 6 is a cross-section of the lamp holder of Figure 5 perpendicular thereto, Figures 7 and 8 are details of part of the holder of FigureS, Figures 9 and 10 show the holder of Figure 5 while being mounted on the track.

The tracks of Figures 1 and 2 each consists of a track body formed of a length of extruded polyvin lychloride 1 associated with a support formed of a length of extruded aluminium 2. The track body comprises side walls 3 each having a lower inturned flange 4 and an upper inturned flange 5 below the upper edge 6 of the wall. The upper flange is attached to a downwardly extending inner wall 7 having inturned projections 8 and a lower portion 9 joining the two inner walls 7 of the body together.

The support 2 of generally U-shaped cross-section is positioned with its limbs between walls 3 and 7 and its base in contact with portion 9. Portion 9 and the base of the support 2 are provided with holes 10 at intervals to receive screws to mount the track on a wall or other support In the track of Figure 1 the whole of portion 9 is in contact with the support, in the track of Figure 2 a gap 26 is provided between them.

Flange 5, projections 8 and portion 9 between them define three grooves 11 on both sides of the track and five of these grooves are intended to contain copper wires 12. In the arrangement shown in the drawings only three of the grooves are actually occupied by wires 12. The bottoms of grooves 11 to receive the wires are shaped as shown to extend around the wires by moie than 1800 and so hold the wires in place. One of the upper grooves, 11', is not intended to contain a wire.

In the arrangement shown in the drawings the wire in upper groove 12a is intended to act as an earth and wires 12b and 12c are live and neutral leads respectively. Wires 1 2b and 1 2c may be joined in a circuit by a lamp holder such as shown in Figures 5 to 10.

As shown in Figure 5 the lamp holder comprises a boss 31 on which is mounted a plinth 32 carrying a light fitting bracket 33 and a cord grip 34. The boss carries radially outwardly projecting metal tongues 35a, 35b and 3which are connected within the boss to wires 36a, 36b and 36c respectively. Wires 36a, 36b and 36c comprise, respectively the earth, live and neutral leads for an electric lamp carried by bracket 33 and pass through cord grip 34 to be connected to the lamp, which is not shown in the drawings. Live wire 36b is surrounded by an insulating boot 37 inside the plinth. The boss 31 also carries an outward projection 44 for locating the boss in the channel of the track.

As shown in Figure 6 and 9 the plinth 32 has diametrically opposed extensions 38 which extend radially outwardly from the central axis of boss 31 and at right angles to tongues 35. Eoth e, Sensions 38 are provided with locking page 39 rotatable and movable vertically between raised and lovjered positions in boxes provided in the extensions, as shown in Figures 7 and 8. Each peg comprises a head 40 having a planar side 41 and a foot 42. When the peg is in its raised position, shown in Figure 8, the foot is withdrawin within the body of the extension; in its lower position the foot projects a short distance below the bottom of the extension.In both upper and lower positions the peg is rotatable through 90"; the upper surface of the extension has an indent 43 to receive the head 40 in its lower position.

Boss 31 is dimensioned such that it may be inserted in space 21 of the track in the position shown in Figure 9. In this position the tongues 35a, 35b, 35c and projection 44 extend in the longitudinal direction of the channel. With the pegs 39 in their raised positions, shown in Figure 9 the boss and plinth may be rotated through 90" to the position shown in Figure 10. In this position the projection 44 extends into the groove 11', locating the boss in the channel, and tongues 35 enter the grooves containing the wires to establish elecrea contact and join the lamp in a circuit with the wires.

When the boss and piinth are in the position shown in Figure 10 the pegs 39 may be lowered so that feet 2 enter the channel and the pegs rotated to the position shown in Figures 7 and 10. The feet are shaped so that in this position the end surfaces 45 of the feet enter the upper grooves to locate and lock the lamp holder in position on the track. The above-described sequence of operations may be reversed to remove the lamp holder from the track.

The track is provided with lid or cover 13 having a pair of downwardly extending ribs 14 with outwardly projecting lower edges to form a snap fit with flanges 5. The lid is dimensioned so that its upper surface is flush with the edges 6 of the wall when assembled with the track. The lid may be appiied to the track when the holders have been mounted at their desired positions along the track, enclosing the parts of the track left between adjacent lamp holders.

Lid 13 may be supplied in relatively short standard lengths, or cut to length as required, to allow fitting with the lamp holders in different positions.

The terminal end fitting comprises a body 15 of the same outer dimensions as the track body 1 attached to a plug moulding 16 dimensioned to slide into the gap 21. Moulding 16 carries tongues 17 which are outwardly sprung to make contact with the wires 12a, 12b and 12cwhen the plug is inserted in gap 21 and the tongues are connected to terminals 18 inside the terminal end fitting. Terminals 18 may be connected to live, neutral and earth wires of a power circuit, these wires passing through hole 19. After connection of these wires to the terminals the terminal end fitting is closed by lid 20 which is secured in place by screw 22 engaging a female threaded insert 23 in the plug moulding.

As may be seen in Figure 3, the plug moulding is provided with an outwardly projecting tab 24 positioned to enter the channel 11 which does not contain a wire to locate the plug moulding as it is inserted in the track.

Figure 4 shows a forwardly extending earth tab 25 on the plug moulding which is positioned to enter tWe space 26 between the potion 9 and the support 2 of the rack and to make eiecti-icai contact with the support 2 when the piuo moulding is inserted in the track of the type shown in Figure 2. Tab 25 is connected to the earth terminal in the terminal end fitting so that the support 2 is earthed.

The end of the track remote from the terminal end fitting is closed by an end stop 27 which may be secured in place by screw 28 passing through a hole in lid 13.

In the above-described arrangement only three of the channels 11 are occuplied by wires. It is possible to provide live and neutral wires in the lowermost of these channels also and to provide a terminal end fitting with five terminals and tongues 17 to correspond to the wires in the track. It is thus possible to provide two separate circuits in the track which can be engaged by bosses having tongues in different respective positions. This feature allows two sets of lamps mounted on the same track to be illuminated selectively. Alternatively, a single holder may have a total of five tongues extending from the same boss so that a single holder can support two independent circuits.

The arrangement described above allows a large number of lamps or other electrical devices to be mounted easily on a single track installation which has a neat and uncluttered appearance. The number of devices may be varied at will and their positions are infinitely variable along the track. The lampholders described above are easily and rapidly fitted and removed on the track and the arrangement of the locking heads allows this operation to be carried out with one hand.

The track described may be mounted on a wall, ceiling or any other support surface or, as it is rendered substantially rigid by support 2, it may be held in position at its ends without intermediate support.

The arrangement described is especially useful in theatres, disco clubs and the like where the arrangement of the lighting is to be varied according to requirements.

Claims (13)

1. A track for supporting electrical devices comprising an elongate channel member of substantially uniform cross-section of electrically insulating material having a plurality of longitudinal grooves, each groove opening into the interior of the channel from a side wall, and at least two of the grooves containing an exposed wire extending along the groove for connection to an electric circuit, and engageable by a connector extending into the groove from within the channel.

2. A track according to Claim 1, having at least one pair of diametrically opposed grooves containing wires.

3. A track according to Claim 1 or 2, in which the wires are positioned at the bottoms of the grooves and surrounded by the insulating material of the channel through an angle of more than 180 so that the wires are retained in the bottoms of the grooves.

4. A track according to any preceding claim, provided with a longitudinal metal support to stiffen the track.

5. A track according to any preceding claim, provided with a snap-on lid to close the parts of the channel not engaged by the connector.

6. A track according to any preceding claim, provided with a terminal end fitting comprising an enclosure having terminals for connection to a power supply and a plug moulding shaped to slide into the channel from an open end thereof, the plug moulding comprising outwardly projecting tongues arranged to slide into the grooves and establish electrical contact with the wires therein, the tongues being electrically connected to the terminals.

7. A track for supporting electrical devices, substantially as hereinbefore described with reference to the accompanying drawings.

8. A track assembly comprising a track according to any preceding claim and at least one connector capable of extending into the channel and engaging at least two wires in their respective grooves.

9. An assembly according to Claim 8, in which the connector comprises a boss having radially outwardly projecting metal tongues which engage the respective wires in the grooves on insertion of the boss in the channel and rotation of the boss.

10. An assembly according to Claim 9, in which the boss has a locating projection positioned to enter a groove in the channel which does not contain a wire in order to locate the boss relative to the grooves on insertion of the boss and rotation thereof in the channel.

11. An assembly according to Claim 8,9 or 10 in which the connector has locking means for locking it in position in the channel when it has engaged the wires.

12. An assembly according to Claim 11, in which the locking device comprises a rotatable peg having a foot extending into the channel, the foot being such that on rotation it can abut opposite inside surfaces of the channel to retain the connector in position.

13. A track assembly, substantially as hereinbefore described with reference to the accompanying drawings.