IE940052A1

IE940052A1 - A locking device

Info

Publication number: IE940052A1
Application number: IE940052A
Authority: IE
Inventors: Dermot Hurst
Original assignee: Square D Co
Priority date: 1994-01-21
Filing date: 1994-01-21
Publication date: 1995-07-26
Also published as: GB2285887A; GB9419928D0

Abstract

A locking device 1 for locking a handle 2 of a circuit breaker 3 in an off position comprises a head piece 10 and a pair of mounting legs 11,12. The legs 11,12 have laterally extending mounting projections 13,14 for engaging behind return ledges 8 on opposed sides of a slot 6 of the circuit breaker through which the handle 2 moves. The leg portions 11,12 are hinged to the head piece and are biassed into a normally engaged or locked position. Fixing means for fixing the mounting legs 11,12 in a desired locked position is provided by an extension piece 20 hinged to the head piece 10. The extension 20 includes extension lugs 21,22 with holes 25, 26 which are aligned in the locked position to receive the shank of a padlock. Accidental operation of the circuit breaker is thereby prevented.

Description

A locking device 1 for locking a handle 2 of a circuit breaker 3 in an off position comprises a head piece 10 and a pair of mounting legs 11,12. The legs 11,12 have 5 laterally extending mounting projections 13,14 for engaging behind return ledges 8 on opposed sides of a slot 6 of the circuit breaker through which the handle 2 moves. The leg portions 11,12 are hinged to the head piece and are biassed into a normally engaged or locked position. 10 Fixing means for fixing the mounting legs 11,12 in a desired locked position is provided by an extension piece 20 hinged to the head piece 10. The extension 20 includes extension lugs 21,22 with holes 25,26 which are aligned in the locked position to receive the shank of a padlock. Accidental operation of the circuit breaker is thereby prevented.

The invention relates to a locking device for locking the handle of a circuit breaker or the like in a required position.

It is often essential to ensure that electrical equipment 5 cannot be operated while work is being carried out on the equipment. Electricians generally ensure that the circuit breakers associated with the equipment are in the off position. However, there is a risk that the circuit breakers may be accidentally operated while the equipment is being worked on. Various attempts are made to secure the breakers in the off position; for example by locking the housing in which the breakers are mounted, however none of these methods is entirely safe and satisfactory.

This invention is therefore directed towards providing a locking device for locking the handle of a circuit breaker or the like in a required position.

According to the invention there is provided a locking device for locking the handle of a circuit breaker or the like in a required position comprising a locking member having means to prevent operation of the handle and mounting means for mounting the locking member to the circuit breaker.

In a preferred embodiment of the invention the means for preventing operation of the handle comprises a locking means for engagement by the handle in use to prevent operation thereof. Preferably the mounting means includes means for engaging a circuit breaker housing.

OPEN TO PUBLIC INSPECTION UNDER SECTION 28 AND RULE 23 JNL. No ......OF In a preferred embodiment the mounting means includes means for engaging a circuit breaker housing adjacent a slot in the housing through which the handle moves, on operation. Preferably the mounting means includes projections for engaging a circuit breaker housing behind a slot therein through which the handle moves, on operation. Typically the projections comprise first and second projections for engagement behind and on opposed sides of a slot in the circuit breaker housing. Preferably the mounting means includes biassing means for urging the projections into an engagement position.

In a preferred embodiment the biassing means is integral with the mounting means. Preferably the projections are provided on respective mounting legs, the legs being biassed into an engagement position.

Typically the means to prevent operation of the handle comprises the mounting legs, a head piece extending between the legs. Preferably the locking device includes fixing means for fixing the mounting legs in a locked position. In a preferred arrangement the fixing means is integral with the head piece. Preferably the fixing means comprises an extension of the head piece which is movable from an unlocked position in which the movement of the mounting legs is not obstructed to a locked position in which movement of the mounting legs is substantially prevented.

In one embodiment of the invention the extension includes a pair of lugs for engagement with portion of the mounting legs in the locked position. Preferably the extension is hingedly mounted at a front edge of the headpiece.

In one arrangement the lugs and mounting legs include means for receiving a padlock or the like. Typically the means for receiving a padlock comprises receiving holes in the lugs and mounting legs which are aligned in the locked position to receive a padlock.

Preferably the locking device is integrally moulded from a plastics material.

The invention will be more clearly understood from the following description thereof, given by way of example only with reference to the accompanying drawings in which:Fig. 1 is a perspective view of a locking device according to the invention in an unlocked position; Fig. 2 is a side elevational view of the locking device of Fig. 1; Fig. 3 is a plan view of the locking device of Fig. 1; Fig. 4 is a perspective view of the device of Fig. 1 in a locked position; Fig. 5 is a side elevational view of the locking device in the position of Fig. 4; Fig. 6 is a plan view of the locking device in the position of Fig. 4; Fig. 7 is a perspective view of portion of a circuit breaker; Fig. 8 is a perspective view of portion of a circuit breaker with a locking device according to the invention in position; Fig. 9 is a side elevational view of portion of a circuit breaker with the locking device in position; Fig. 10 is a plan view of a portion of the circuit breaker of Fig. 8; and Fig. 11 is a detailed view of the engagement between the circuit breaker and locking device of the invention.

Referring to the drawings, there is illustrated a locking device according to the invention indicated generally by the reference numeral 1 for locking a handle 2 of a circuit breaker, portion 3 of which is illustrated in some of the drawings, in a required position, usually in an off position. The circuit breaker includes a housing 5 having a front slot 6 through which the handle 2 moves in normal operation. The housing 5 includes return ledges 8 on opposed sides of the slot 6.

The locking device 1 in this case is integrally moulded from a plastics material and has means for preventing operation of the handle 2 and mounting means for mounting the locking member to the housing 5 of the circuit breaker 3. In more detail, the locking device 1 comprises a head piece 10 and a pair of mounting legs 11, 12 having laterally extending mounting projections 13, 14 respectively for engaging behind the ledges 8 of the circuit breaker housing 5 in a locked position as illustrated particularly in Fig. 10. The leg portions 11, 12 are hingedly mounted to the head piece 10 by integral plastic hinges 15, 16 respectively and are biassed into the normally engaged or locked position illustrated in Figs. 8 to 11.

Fixing means for fixing the mounting legs 11, 12 in a desired locked position is in this case provided by an extension 20 which is hingedly mounted by a plastics hinge 20a to the head piece 10. The extension 20 includes a pair of extended lugs 21, 22 respectively, the extension 20 being hinged about a hinge 20a for movement between a released position illustrated in Fig. 1 and a locked position illustrated in Fig. 4 in which the lugs 21, 22 are engaged between the legs 11, 12. It will be noted that both the legs 11, 12 and lugs 21, 22 are provided with holes 25, 26 respectively which are aligned in the locked position to receive the shank of a padlock or the like (not shown).

In use, when it is desired to lock the handle 2 of the circuit breaker 3 in a required position, with the locking device 1 in the position illustrated in Fig. 1 the legs 11, 12 are pressed together by finger pressure allowing the projections 13, 14 to be pushed into the slot 6 to engage behind the ledges 8 of the circuit breaker housing 5. Finger pressure is then released and the extension 20 is hinged inwardly in the direction of the arrow illustrated in Fig. 1 until the lugs 21, 22 are aligned with the mounting legs 11, 12. The lugs 21, 22 are arranged to substantially prevent movement of the legs 11, 12 to prevent the projections 13, 14 being removed from behind the ledges 8 of the circuit breaker housing 5. In this position the mounting legs 11, 12 are engaged below the handle 2 preventing its operation. A padlock may be fitted through the holes 25 and 26 in the lugs 21, 22 and mounting legs 11, 12 for further security.

For ease of manufacture and minimum expense it is anticipated that the locking member will be injection moulded from a plastics material. However, it will be appreciated that the locking member may be of any suitable material of construction.

Many variations on the specific embodiment of the invention described will be readily apparent and accordingly the invention is not limited to the embodiments hereinbefore described, which may be varied in both construction and detail.

Claims

1. A locking device for locking the handle of a circuit breaker or the like in a required position comprising a locking member having means to prevent operation of the handle and mounting means for mounting the locking member to the circuit breaker. 2 . A locking device as claimed in claim 1 wherein the means for preventing operation of the handle comprises a locking means for engagement by the handle in use to prevent operation thereof. 3. A locking device as claimed in claim I or 2 wherein the mounting means includes means for engaging a circuit breaker housing. 4. A locking device as claimed in any of claims 1 to 3 wherein the mounting means includes means for engaging a circuit breaker housing adjacent a slot in the housing through which the handle moves, on operation. 5. A locking device as claimed in claim 4 wherein the mounting means includes projections for engaging a circuit breaker housing behind a slot therein through which the handle moves, on operation. 6 . A locking device as claimed in claim 5 wherein the projections comprise first and second projections for engagement behind and on opposed sides of a slot in the circuit breaker housing. 7 . A locking device as claimed in claim 6 wherein the mounting means includes biassing means for urging the projections into an engagement position. 8. A locking device as claimed in claim 7 wherein the biassing means is integral with the mounting means . 9. A locking device as claimed in claim 8 wherein the projections are provided on respective mounting legs, the legs being biassed into an engagement position. 10. A locking device as claimed in claim 9 wherein the means to prevent operation of the handle comprises the mounting legs, a head piece extending between the mounting legs . 11. A locking device as claimed in claim 10 including fixing means for fixing the mounting legs in a locked position. 12. A locking device as claimed in claim 11 wherein the fixing means is integral with the head piece. 13. A locking device as claimed in claim 11 or 12 wherein the fixing means comprises an extension of the head piece which is movable from an unlocked position in which the movement of the mounting legs is not obstructed to a locked position in which movement of the mounting legs is substantially prevented. 14. A locking device as claimed in claim 13 wherein the extension includes a pair of lugs for engagement with portion of the mounting legs in the locked position. 15. A locking device as claimed in claim 13 or 14 wherein the extension is hingedly mounted at a 5 front edge of the headpiece. 16. A locking device as claimed in claim 14 or 15 wherein the lugs and mounting legs include means for receiving a padlock or the like. 17. A locking device as claimed in claim 16 wherein 10 the means for receiving a padlock comprises receiving holes in the lugs and mounting legs which are aligned in the locked position to receive a padlock. 18. A locking device as claimed in any preceding claim 15 which is integrally moulded from a plastics material. 19. A locking device substantially as hereinbefore described with reference to the accompanying drawings. CRUICKSHANK & CO.,

2. 0 CJ\SPEC4\SQD.DEC