GB2216343A - Connector for an electrical supply track - Google Patents

Abstract

Ends of terminals (9, 10) of a plug for an electrical supply track (not shown) are moved against resilent bias from inside the plug to outside the plug and in contact with the track conductors by a cam (19). The cam (19) clamps the terminals against the body of the plug when the ends are outside the plug and is mechanically interlocked with means (7) for mechanically coupling the plug to the track. <IMAGE>

Description

CONNECTOR FOR AN ELECTRICAL SUPPLY TRACK This invention relates to a connector for use with an electrical supply track and particularly but not exclusively to a connector for the take off of electrical power from an electrical mains supply track of a power distribution system.

Such systems are known in which an elongate track defining a channel houses two or more conductors which extend the length of the track. The take off or supply of power from the track typically requires a connector to be coupled to the track such that a portion of the connector extends into the channel to enable contact elements carried by that portion to make connection with the conductors.

According to the present invention there is disclosed a connector for use with an electrical supply track and having means for mechanically coupling the connector to the track at an adjustable position along its length and switch means operable when the connector is so coupled to make contact with electrical conductors extending longitudinally within an elongate channel of the track, wherein the switch means comprises contact elements in resilient strip form mounted for cantilever movement with respect to the connector body such that a free end portion of an element is moveable between an operative position in which contact is made with a respective track conductor and an inoperative position in which the free end is retracted to facilitate mechanical coupling and decoupling of the connector, the switch means further comprising cam means operable on the elements for movement thereof into the operative position against spring bias provided by resilience of the elements and clamping means acting on the elements adjacent the free end portion thereof for clamping the elements in the operative position.

An advantage of such an arrangment is that it combines the simplicity of construction afforded by resilient strip cantilever elements with the positive location of the elements in the operative position afforded by the clamping means.

Preferably each of the elements are clamped in the operative position between respective cam surfaces of the cam means and a respective inner wall surface of the connector body thereby constituting a clamping means.

Conveniently at least one element is L shaped having a first arm extending longitudinally along the body and mounted for lateral cantilever movement relative to the body, a second arm extending from the free end of the first arm and terminating in a tab defining a contact surface engageable in the operative position with a respective track conductor and wherein a respective cam surface is engageable with the element adjacent the free end of the first arm.

An advantage of such an arrangement is that for each element the extent to which the tab is spring biased in to contact with a track conductor by resilience of the second arm is independent of the extent to which the first arm is spring biased in to contact with the cam. It is therefore possible to provide relatively strong spring bias of the tab whilst developing relatively weak spring bias against the cam.

Preferably the connector includes interlock means which prevents the mechanical coupling means being actuated so as to decouple the connector from the track while the switch means is in an operative position.

Conveniently both the switch means and the mechanical coupling means are actuated by first and second actuating shafts respectively and wherein the interlock means comprises first and second cam formations carried by the respective shafts, the cam formations being mechanically coupled to permit rotation of the first shaft only when the second cam formation is in a predetermined position corresponding to the operative position of the mechanical coupling means and the second shaft is rotatable only when the first cam formation is in a predetermined position corresponding to the inoperative position of the switch means.

Conveniently the cam formations are coupled by an interlock member, extending between the cam format ions and reciprocatably moveable between first and second positions in which one or other of the respective cam formations are prevented from rotating.

A particular embodiment of the present invention will now be described by way of example only and with reference to the accompanying drawings of which: Figure 1 is a perspective view from above and one side of a connector with the switch in the operative position and with mechanical coupling means in the operative position, Figure 2 is a plan view of the connector of Figure 1 in the same operative position, Figure 3 is a sectional elevation of the connector of Figures 1 and 2 in the same operative state, Figure 4 is a fragmentary plan view of the connector of Figures 1, 2 and 3 showing detail of the switch means in the inoperative position, Figure 5 is a sectional plan view taken at 5-5 of Figure 3 and, Figure 6 is a sectional plan view corresponding in section to Figure 5 but showing the connector with both the switch and coupling means in an inoperative position.

The connecter 1 of Figure 1 comprises a body 2 of a plastics material which is of elongate shape.

The width of the body 2 is stepped at a shoulder 3 del imitating between an upper body portion 4 and a lower body portion 5 of greater width. The upper body portion 4 is shaped in cross-section so as to be insertable in a channel of a supply track (not shown) such that when so inserted the lower body portion 5 projects visibly from the track. The connector 1 as described and as shown in the drawings is orientated for connection with an overhead track such as might be installed across the ceiling of a room so that the connector when coupled depends from the track.

References to the horizontal and vertical in the description are intended to be interpreted as relating to the connector when so orientated.

A spigot 6 depends from the lower body portion 5 and is adapted for mounting of a spotlight (not shown) receiving electrical power from the track by means of the connector 1.

A locking arm 7 projects on either side of the upper body portion 4 through apertures 8 and cooperates with a re-entrant formation of the track (not shown) to mechanically lock the connector 1 at any desired position along the track.

Electrical connecting tabs 9 and 10 project laterally on either side of the upper body portion 4 at its uppermost extent and make electrical contact with conductors within the track channel (not shown).

As seen more clearly in Figures 2 and 3 the tabs 9 and 10 comprise the free end portions of contact elements 11 and 12 respectively which are formed from resilient sheet metal. As seen in Figure 3 the contact element 12 is generally of L shape having a first arm 13 extending longitudinally with respect to the body 2 and oriented with the sheet plane vertical. The first arm 13 has a fixed end 14 which is attached to a terminal 15 adapted to receive a conducting wire (not shown) and including a screw fitting for clamping the wire.

At the opposite end of the first arm 13 a second arm 16 extends upwardly in the same plane and terminates in the tab 10 which is formed by bending an end portion of the second arm into a horizontal plane and so as to extend laterally away from the body 2.

The second contact element 12 is similar in shape but has a first arm 17 which is greater in length and is attached to a second terminal 18 spaced longitudinally from the first terminal 15. The tabs 9 and 10 extend away from opposite sides of the body 2 in the opposite directions to one another.

A cam 19 is fixedly mounted on a rotatable vertical shaft 20 between the second arm 16 of the second contact element 12 and the second arm 21 of the first contact element 11. The cam 19 has a cam surface 22 configured such in one position of the cam as shown in Figure 2 the contact elements 11 and 12 are held apart against spring action. In this position the second arm 16 is clamped between the cam surface 22 and an internal wall of the body 2, the second arm 21 of the first contact arm 11 similarly being clamped between an opposing area of the cam surface 22 and an opposing internal wall 24 of the body.

In this clamped position each of the second arms 16 and 21 are rigidly clamped at their lower ends whilst at their upper ends contact surfaces 40 and 41 of the tabs 9 and 10 make contact with the respective track conductors (not shown). The tabs 9 and 10 are arranged such that in this position they are spring biased in to contact with the track conductors by resilience of the second arms 16 and 21.

-The cam surface 22 is configured so that when turned through 90 degrees from the above position as shown in Figure 4 the contact elements 11 and 12 are able to retract under spring action to a position in which the tabs 9 and 10 no longer project from the body 2.

The spring action referred to above is developed from the resilience of the metal forming the contact elements which are pre-formed to adopt the retracted position.

The cam 19 is rotatable between these positions by means of a handle 25 which projects beneath the body 2 so as to be readily accessible.

The locking arm 7 comprises a plate of generally rectangular outline extending in a horizontal plane and is fixedly mounted on a rotatable shaft 26 extending vertically in the body 2 such that by rotation of the shaft the locking lever is rotatable.

The rotatable shaft 26 is journalled in a block 42 which extends longitudinally within the body 2.

The first arms 13 and 17 of the elements 11 and 12 extend on either side of the block 42 and are rigidly supported between the block and internal walls 23 and 24 of the body. The first arms 13 and 17 extend beyond the block 42 towards the cam 19 by a distance sufficient to provide cantilever movement there between.

In one position of the locking arm 7 as shown in Figure 2 the opposite ends of the locking arm 7 project from the body 2 through the apertures 8 to provide locking action in cooperation with the track.

The locking arm 7 can be retracted within the body 2 by rotation of the shaft 26 through 90 degrees such that the long axis of locking lever extends parallel to the body. To assist easy engagement with the track the leading corners 27 of the locking arm are chamfered.

The shaft 26 is rotatable by means of a handle 28 projecting beneath the body 2. The handles 28 and 25 are styled such that in the normal operating condition of the connector 1 in which both the tabs 10 and the locking arm 7 project laterally from the body 2 the handles comprise a lower surface of the body.

The upper side of the handle 25 includes an upwardly projecting cam formation 29 accommodated in an annular recess 30 formed in the body 2 around the shaft 20. The handle 28 similarly includes a cam formation 31 accommodated in an annular recess 32 and the two recesses 30 and 32 are connected by a longitudinally extending channel 33 in which is located an interlock member 34 in the form of a plate which is longitudinally slideable within the chamber 33.

The cam formation 29 is generally circular with a flat face 35 arranged such that when the shaft 20 is in a position such that the cam 19 allows the contact elements 11 and 12 to be retracted then the flat face is aligned with the channel 33 and the interlock member 34 can be moved into abuttment with the flat face.

When the shaft 20 is moved through 90 degrees to a position in which the cam 19 forces apart the contact elements 11 and 12 in the extended position then the flat face 35 is no longer directed towards the channel 33. Such a rotational movement will result in longitudinal movement of the interlock member 34 in a direction away from the shaft 20.

The cam formation 31 associated with the locking arm 7 by the shaft 26 similarly is generally circular and as a second flat face 36 which is directed towards the channel 33 for abuttment with the interlock member 34 when the locking arm 7 is in its extended position as shown in Figures 1, 2 and 3.

The length of the interlock member 34 is selected such that it cannot be accommodated between the two cam formations 29 and 31 unless one or other of the flat faces 35 and 36 is directed towards the channel 33. This has the effect as shown in Figure 5 the shaft 26 associated with the locking lever 7 cannot be rotated when both the contact elements 11 and 12 and the locking arm 7 are in their respective extended positions. In this condition however it is possible to rotate the shaft 20 associated with the cam 19 so as to retract the contact elements 11 and 12 and in doing so the flat face 35 would be brought into registration with the channel 33. Subsequent rotation of the shaft 26 would then be possible to permit retraction of the locking arm 7 by movement of the handle 28.

The interlock member 34, the channel 33 and the cam formations 31 and 29 together comprise an interlock means which prevents coupling and decoupling of the connector 1 with respect to the track whilst the contact elements 11 and 12 are in their extended condition.

The contact elements 11 and 12, the cam 19, the shaft 20 and the handle 25 together comprise a switch operable to make and break connection between the connector 1 and the conductors of the track. The interlock means also can be seen to function such that the switch is only operable to make contact when the locking arm 7 is in its extended position.

Whilst the connector 1 has been described with reference to the take off of power from a track it will be apparent to those skilled in the art that the connector 1 may be modified to receive a power supply cable instead of a spotlight spigot such that the connector 1 can be used as a power supply connector for energising the track.

Alternative arrangements may include a cam which is slideable rather than rotatable and conveniently such a slideable cam would be moveable in the longitudinal direction and would move the contact elements by wedge action.

A further alternative embodiment would dispense with the need for an interlock member by using cam formations associated with the respective shafts which are sufficiently close together such that the cam formations interfere ie rotation of one cam formation is only possible when the other formation presents its flat face towards that formation.

Other arrangements are also possible in which the connector is used for the take off of power and is connected to a cable dependent from the body 2 for the supply of a device remote from the connector.

The connector may also be adapted to include more than two contact elements arranged for contact with a corresponding number of conductors of the track and such an arrangement may include more than one switch for selectively extending different sets of contact elements as may be required.

The connector may carry additionally other types of contact element which are not switchable in the manner described as for example in the case of an earth contact which engages an earth connector peripheral to or outside of the channel of the track.

Claims (9)

CLAIMS:

1. A connector for use with an electrical supply track and having means for mechanically coupling the connector to the track at an adjustable position along its length and switch means operable when the connector is so coupled to make contact with electrical conductors extending longitudinally within an elongate channel of the track, wherein the switch means comprises contact elements in resilient strip form mounted for cantilever movement with respect to the connector body such that a free end portion of an element is moveable between an operative position in which contact is made with a respective track conductor and an inoperative position in which the free end is retracted to facilitate mechanical coupling and decoupling of the connector, the switch means further comprising cam means operable on the elements for movement thereof into the operative position against spring bias provided by resilience of the elements and clamping means acting on the elements adjacent the free end portion thereof for clamping the elements in the operative position.

2. A connector as claimed in claim 1 wherein each of the elements are clamped in the operative position between respective cam surfaces of the cam means and a respective inner wall surface of the connector body thereby constituting the clamping means.

3. A connector as claimed in claim 1 or 2 wherein at least one element is L shaped having a first arm extending longitudinally of the body and mounted for lateral cantilever movement relative to the body, a second arm extending from the free end of the first arm and terminating in a tab defining a contact surface engageable in the operative position with a respective track conductor and wherein a respective cam surface is engageable with the element adjacent the free end of the first arm.

4. A connector as claimed in claim 3 having two elements engageable by respective surfaces of a single rotatable cam and wherein the respective tabs project laterally from opposite sides of the connector body in an operative position of the switch means.

5. A connector as claimed in any preceding claim and having interlock means which prevents the mechanical coupling means being actuated so as to decouple the connector from the track while the switch means is in an operative position.

6. A connector as claimed in claim 5 wherein both the switch means and the mechanical coupling means are actuated by first and second actuating shafts respectively and wherein the interlock means comprises first and second cam formations carried by the respective shafts, the cam formations being mechanically coupled to permit rotation of the first shaft only when the second cam formation is in a predetermined position corresponding to the operative position of the mechanical coupling means and the second shaft is rotatable only when the first cam formation is in a predetermined position corresponding to the inoperative position of the switch means.

7. A connector as claimed in claim 6 wherein the cam formations are coupled by an interlock member extending between the cam formations and reciprocatably moveable between first and second positions in which one or other of the respective cam formations are prevented from rotating.

8. A connector as claimed in any preceding claim wherein the elements are spring biassed into contact with the track conductors to a different extent from the extent to which they are spring biased into engagement with the cam means.

9. A connector substantially as hereinbefore described with reference to and as shown in the accompanying drawings.