GB2243255A

GB2243255A - Plug arrangement

Info

Publication number: GB2243255A
Application number: GB9113725A
Authority: GB
Inventors: Daniel Joseph Fitzgerald; Glenn Robert Page
Original assignee: MK Electric Ltd
Current assignee: Novar ED&S Ltd
Priority date: 1987-03-30
Filing date: 1991-06-25
Publication date: 1991-10-23
Anticipated expiration: 2007-03-30
Also published as: GB2243255B; GB2245433B; GB8707524D0; GB9113725D0; GB2203299A; GB2245433A; GB2203296A; GB2203296B; GB9113724D0; GB2203299B; GB8807145D0

Abstract

An electric plug and socket comprising a socket having a plurality of apertures to receive the respective pins of an electric plug and a plug having pins to enter the apertures. The plug and socket have interengaging means 18, 19 forming a hinge such that the plug may be engaged with and disengaged from the socket and while engaged rotated about the hinge to a position in which its pins pass through the socket apertures. <IMAGE>

Description

PLUG ARRANGEMENT This invention relates to a track for supplying electric current suitable for installation below a false floor of a building, and a plug suitable =or use with such a track.

Many office and other buildings are now provided with false floors comprising a floor maoe up of flooring slabs or tiles which are mounted, usually on pedestals, above the main floor of the room in which they are installed. The gap formed between the false floor and the main floor, commonly a few inches in depth, may be used for accommodating pipes or cables running across the room below the false floor. This feature allows take-off points for electrical cables, for telephones computers and the like and also for power supply cables, to be installed not only on or by the walls of the room in traditional manner but also at points on the floor of the room, without the need for cables running across the upper surface of the false floor.Such a false floor is of particular advantage in open-plan offices containing a large number of working stations requiring telephones and other electrical services in the middle of the room.

Our European Patent Application 0106535 describes a track for electric power supply comprising exposed electrical conductors running along the track so that a socket for receiving a plug may be attached to the track at any point along its length for drawing electric current from the conductors. The track described in this European Patent Application is primarily intended to be mounted on the wall or skirting of a room. The present invention is intended to provide an electric track which is suitable for mounting below a false floor in which a plug may be connected to the track, or a cable outlet provided, at any point along the track.

According to one aspect of the invention, there is provided a track for supply of electric current comprising an open-topped longitudinal duct capable of being installed below a false floor, the duct containing a plurality of exposed longitudinal electrical conductors for current supply, the duct being provided with a removable cover having a hole capable of receiving an electric plug, the duct containing a socket of electrically insulating material between the conductors and the cover and aligned with the hole to receive the plug, the socket comprising apertures capable of receding pins of the plug to ,.ake electrical contact with the conductors, and resilient means adapted to lock the plug in place when the plug is t 5 inserted the socket.

According to ac=er aspect of the invention, there is provided a track for supply of electric current comprising at least one longitudinal duct capable of being installed below a false floor, the channel containing a plurality of exposed electrical conductors for current supply, the duct being provided with a removable cover having hole capable of receiving an electric plug, and the cover having mounted on the inside surface thereof a socket of electrically insulating material aligned with the hole to receive the plug, the socket fitting within the.duct and comprising apertures capable of receiving pins of the plug to make electrical contact with the conductors.

In one embodiment of the invention the resilient means comprises a plate slidable in the longitudinal direction of the duct and biassed by a spring to engage the plug when the plug is inserted in the socket. The plate may comprise a shutter mounted on the lower surface of the cover, the shutter being urged by the spring to a position in which it closes the hole when the socket is not occupied by a plug.

According to another aspect of the invention, there is provided an electric plug and socket combination comprising a socket having a plurality of apertures to receive the respective pins of an electric plug and a plug having pins to enter the apertures, the plug and socket having interengaging means forming a hinge such that the plug may be engaged with and disengaged from the socket and while engaged rotated about the hinge to a position in which its pins pass through the socket apertures.

The apertures may be staggered in a direction transverse to the axis of the hinge so that on rotation of the plug the pins enter their respective apertures successively. The interengageable means may comprise a pair of opposed lugs on inside walls of the socket and a corresponding pair of slots on the plug, or vice-versa, the lugs and sockets being such that the plug may be engaged with and disengaged from the socket while in an angular position in which the pins do not pass through the apertures and, when the plug is rotated about the hinge to a position in which the pins pass through the apertures, the hinge prevents the plug being disengaged from the socket.

According to yet another aspect of the invention, there is provided a track for electric cables comprising an open-topped longitudinal duct capable of being installed below a false floor and a removable cover for covering part of the duct, a bracket member which may be fitted and retained within the duct at any point along the length of the duct, the bracket member comprising inturned flanges adjacent the open top of the duct, and a mounting plate attachable to said flanges to extend above and transverse to the duct adjacent an end of said cover, the mounting plate having apertures for receiving electrical connectors.

Arrangements according to aspects of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a view of an electric track according to one embodiment of the invention, Figure 2 is an exploded view of the track of Figure 1, Figure 3 shows a plug for use with the track of Figure 1, Figures 4 to 7 are diagrammatic views showing application of the plug of Figure 3 to the track of Figure 1, Figure 8 is a transverse cross-section of a track according to another aspect of the invention, and Figure 9 is a longitudinal cross-section of the track of Figure 8.

The track shown in Figures 1 and 2 comprises a longitudinal metal duct 31 containing a connected pair of longitudinal channels each defined by a base 1 and side walls 2 of electrically insulating plastics material. The bottom of each channel has upstanding moulded ribs which define between them grooves 3 in which longitudinal copper conductors (not shown in the drawings) are retained by cleats 4 positioned at intervals along the grooves. The conductors are exposed, that is they are not covered by insulating material, so that an accessory may make electrical contact with them at any point along their length. The structure of each channel is generally similar to that of the electrical track described in European Patent Application 106535.The track shown in Figures 1 and 2 comprises two similar parallel channels but a single channel, or more than two channels side-by-side, may be provided as required. in the embodiment shown each channel contains grooves for three conductors, intended to serve respectively as the live, neutral and earth conductor of a 240V AC power supply circuit.

The channels are covered by a flat cover member 5, which may be of metal or plastics material, having inturned side flanges which snap fit over outstanding flanges 7 of the duct 31.

When the track is installed in a building having a false floor the duct 31 is secured to the underlying floor and in use the duct and cover 5 will be covered by a slab forming part of the floor. However it is necessary that access to the cover 5 can be obtained from above and this may be achieved by providing a hole, which may be protected by a liftable flap, in the slab. Cover 5 has a rectangular hole 8 above the conductors which is closable by sliding shutter 9.

A socket 10 of electrically insulating plastics material fits into the channel between walls 2 below hole 8.

The socket has four walls defining an upper rectangular space which contains a compression spring 12. Shutter 9 is slidable above the socket 10 in the longitudinal direction of the duct and has a pressed-out downwardly extending portion 13 intended to abut spring 12 in the rectangular space. In the assembled condition shown in Figure 1, one end of spring 12 abuts the inside of an end wall 11 and the other abuts portion 13 so that the shutter is urged towards the closed position in which it closes hole 8 above the socket, and can be moved against the spring to the open position shown in Figure 1.

Socket 10 is fixed in place by screws or drive pins applied through holes 32 In the cover 5 and engaging holes 14 in the socket.

The socket has a rectangular lower rE 1 having a bottom 16 abutting the ribs defining grooves 3 and provided with three rectangular apertures 17 above the respective conductors in the channel. The sizes of the socket are also provided with a pair of opposite outstanding lugs 18 to receive a plug as described below.

The plug shown in Figure 3 comprises a body of plastics material having a lower part shaped to fit into the recess 15 of socket 10. One end of the lower part has, on both sides, a pair of jaws 19 intended to fit around lugs 18 on the inner side walls of the socket to provide a hinge for the plug. As shown in Figures 4-7 the lower plug surface has three downwardly extending fork-shaped terminal pins corresponding to the three apertures 17 in the recess bottom and adapted to engage and make electrical contact with the conductors when the plug is inserted in the recess. The upper part of the plug has an aperture (not shown) allowing a three-core electric cable to enter the plug and the inside of the plug has terminals of a conventional type for connecting the cable to the pins. The aperture in the plug may also allow entry of a conduit.The plug is made in two separable parts to allow access to its interior for wiring.

The plug is inserted in the socket in the manner shown in Figures 4-7. The shutter, which in its normal position closes hole 8, is withdrawn against the spring as shown in Figure 4 and the plug is lowered, with the pins extending substantially horizontally, to engage lugs 18 as shown in Figure 5. The lugs and jaws are shaped so that the plug can be engaged and disengaged from the lugs only when in the position shown in Figures 4 and 5, but can be rotated about the lugs after engagement. The plug is then rotated about the hinge formed by lugs 18 and jaws 19 as shown in Figure 6 until it is in the position of Figure 7, the pins extending downwardly through apertures 17 to make contact with the conductors below the holes. The shutter may then be released and is urged by the spring to the position of Figure 7.The upper surface of the plug has a shoulder 20 below the end of the shutter so that the shutter, together with the hinge, holds the plug firmly in place.

The plug is removed from the socket by the reverse procedure.

As shown in the drawings, the three pins of the plug and the corresponding holes in the socket are staggered in the longitudinal direction of the channel so that as the plug is rotated to its position of Figure 7 the pins engage their respective conductors successively rather than simultaneously. The force which has to be exerted on the plug to cause engagement with the conductors is thus reduced. The pins and apertures in the socket are arranged so that the pin engaging the earth conductor is nearest the hinge, so that when the tluo is rotated the earth conductor is engaged by the respective pin before the neutral and live conductors are engaged.

In another alternative embodiment, not shown in the drawings, the shutter 9 is replaced by a srlng-loaed slidable plate mounted in the duct in its lower part, adjacent the conductors. The spring-loaded plate is arranged to operate in the same way as the shutter 9 shown in the drawings, but engages a shoulder or like protrusion of the plug adjacent its lower surface carrying the pins.

When the plug is fitted in the socket as described above the shutter and hinge together hold it fir. in place until the shutter is moved against its spring to release the plug. This feature ensures that the floor-mounted plug will not be displaced accidentally in use. In the embodiment shown in the drawings, wnen there is no plug in the socket the shutter closes the hole in the cover so that the track conductors are protected from spilled liquids and other sources of interference.

The cover having the hole on which the socket is mounted may easily and cheaply be cut to length so that the socket may easily be located at any desired point along the duct. The position of the socket is thus easily altered if an office provided with the track under a false floor is re-arranged.

The plug and socket combination has been described with reference to an underfloor track but it will be understood that a similar hinged plug and socket may be used in other situations, especially when the plug has to be securely mounted in the socket to prevent accidental displacement.

The track shown in Figures 8 and 9 is intended for use with insulated electric cables, for example for telephones or computers, and is again intended to be installed below a false floor and have take-off points for the cables which may be provided at any point along the track. The track again comprises a longitudinal metal duct 31 having a removable cover member 5 which snaps over outstanding flanges 7 of the duct. In this instance cover 5 terminates at point 32 adjacent an upstanding mounting plate 33 which extends transversely across the duct. Plate 33 has apertures 34, which may be of any appropriate shape and size, for receiving connectors for the ends of cables extending through the duct 31.

Mounting plate 33 is attached by screws 35 to a bracket member 36 which fits within the duct. The bracket member has side walls 37 which abut the side walls of duct 31 which have inwardly extending flanges 38 preventing removal of the bracker member from the duct. When the bracket and mounting plate are assembled with the duct as shown interference between the duct and the bracket and between the duct and the plate prevents movement of the bracket and plate in the longitudinal direction of the duct.

The track is also provided with a metal lid 39 of which the side walls have inwardly directed flanges to clip over flanges 7 of the duct. The lid has dimensions corresponding to mounting plate 33 so that the space defined by the duct, plate 33 and lid 39 is ccpletely enclosed. The lid 39 m2v be abutted against an adjacent portion of cover 5 and the cables within the duct may then be completely enclosed by the duct, cover lid 39 and the plate 33.

The bracket 37 and plate 33 may be fitted at any point along the duct 31, the cover 5 being cut to the required length. Any type of electric cable may be laid in the duct and connected to an appropriate connector mounted in an aperture 34. In a track system installed in a building having a false floor both the track of Figure 1 and the track of Figure 8 may be provided below the false floor, the tracks being placed side-by-side so that both power and telephone, computer or other services may be provided at any point along the tracks.

Claims

1. An electric plug and socket combination comprising a socket having a plurality of apertures to receive the respective pins of an electric plug and a plug having pins to enter the apertures, the plug and socket having interengaging means forming a hinge such that the plug may be engaged with and disengaged from the socket and while engaged rotated about the hinge to a position in which its pins pass through the socket apertures.

2. A combination according to claim 1, in which the apertures are staggered in a direction transverse to the axis of the hinge so that on rotation of the plug the pins enter their respective apertures successively.

3. A combination according to claim 1 or 2, in which said interengageable means comprise a pair of opposed lugs on inside walls of the socket and a corresponding pair of slots on the plug, or vice-versa, the lugs and sockets being such that the plug may be engaged with and disengaged from the socket while in an angular position in which the pins do not pass through the apertures and, when the plug is rotated about the hinge to a position in which the pins pass through the apertures, the hinge prevents the plug being disengaged from the socket.

4. A plug and socket combination according to claim 1, substantially as hereinbefore described with reference to Figures 1 to 7 of the accompanying drawings.

5. A track for supply of electric current comprising an open-topped longitudinal duct capable of being installed below a false floor, the duct containing a plurality of exposed longitudinal electrical conductors for current supply, the duct being provided with a removable cover having a hole capable of receiving an electric plug, the duct containing a socket of electrically insulating material between the conductors and the cover and aligned with the hole to receive the plug, the socket comprising apertures capable of receiving pins of the plug to make electrical contact with the conductors, and resilient means adapted to lock the plug in place when the plug is inserted in the socket.

6. A track according to claim 5 in which the resilient means comprises a plate slidable in the longitudinal direction of the duct and biassed by a spring to engage the plug when the plug is inserted in the socket.

7. A track according to claim 6, in which the plate comprises a shutter mounted on the lower surface of the cover, the shutter being urged by the spring to a position in which it closes the hole when the socket is not occupied by a plug.

8. A track for supply of electric current comprising at least one longitudinal duct capable of being installed below a false floor, the channel containing a plurality of exposed electrical conductors for current supply, the duct being provided with a removable cover having a hole capable of receiving an electric plug, and the cover having mounted on the inside surface thereof a socket of electrically insulating material aligned with the hole to receive the plug, the socket fitting within the duct and comprising apertures capable of receiving pins of the plug to make electrical contact with the conductors.

9. The combination of a track according to claim 5, 6, 7 or 8 and a plug to enter the socket, the plug and socket having interengageable means forming a hinge so that the plug may be rotated about the hinge to a position in which its pins pass through the socket apertures.

10. A combination according to claim 9, in which the apertures corresponding to respective conductors are staggered in the longitudinal direction of the duct and the axis of the hinge is transverse to the duct so that on rotation of the plug the pins make contact with their respective conductors successively.

11. A combination according to claim 9 or 10, in which said interengageable means comprise a pair of opposed lugs on inside walls of the socket and a corresponding pair of slots on the plug, or vice-versa, the lugs and sockets being arranged so that the plug may be engaged with and disengaged from the socket while in an angular position in which the plug extends above the socket and the pins do not pass through the apertures and, when the plug is rotated about the hinge to a position in which the pins pass through the apertures, the hinge prevents the plug being disengaged from the socket.

12. A track for electric cables comprising an open-topped longitudinal duct capable of being installed below a false floor and a removable cover for covering part of the duct, a bracket member which may be fitted and retained within the duct at any point along the length of the duct, the bracket member comprising inturned flanges adjacent the open top of the duct, and a mounting plate attachable to said flanges to extend above and transverse to the duct adjacent an end of said cover, the mounting plate having apertures for receiving electrical connectors.

13. A track according to claim 12, in which the duct comprises side walls provided with interior flanges and the bracket member comprises arms engaging said side walls and abutting the interior flanges to retain the bracket in the duct, the inturned flanges of the bracket being attachable to the mounting plate by screws, movement of the bracket along the duct being prevented by interference between the duct and bracket and between the duct and mounting plate.

14. A track according to claim 12 or 13, comprising a lid attachable to the duct such that the duct, mounting plate and lid define an enclosure.

15. A track for installation below a false floor, substantially as hereinbefore described with reference to Figures 1 to 7 or Figures 8 and 9 of the accompanying drawings.