GB2182093A - Locks; door furniture - Google Patents

Abstract

Door furniture for use with an "emergency" lock includes a non-frangible mechanical indicator 28 which moves from a first position to a second position to signal when a handle 21 is moved to unlock the door. The bolt of the lock can be withdrawn from either side of the door using a key but only from inside by handle 21 in emergency. In one embodiment the indicator is a rotatable button 28 having a cam 29 keyed to it behind a mounting plate 22. When the handle is turned, a stop washer 25 turns the cam 29 and therefore also turns the indicator button 28 into second position. In the latter condition a tang 32 on the cam 29 engages in a aperture 34 in the mounting plate 22, under the force of a spring 30 acting axially on the cam. The indicator 28 cannot therefore be roset to its normal position without disassembling the furniture from the door to gain access to the cam 29. In the embodiment of Figure 1 turning of the handle (1) moves a slide (9) to rotate an indicator (8) to a new position, the slide being retained in position to keep indicator in displaced condition. <IMAGE>

Description

SPECIFICATION Lacks The present invention relatesto so-called emergency (orfire-escape) locks and in particularto an item of door furniture for use therewith.

"Emergency" locks are used on doors which are normally to be kept locked but which nevertheless must be capable of being opened atwill to allow passagethrough the door in the event of an emergency. Such locks a re therefore typica lly fitted to doors which are provided as a means of escape from a building in case of fire or other emergency, butwhich are not intended as a normal means of exitorentry or through which passage is normally restricted to authorised persons holding an appropriate key (or other means of code input).In orderto deterthe use of the means of emergency operation such locks except in the case of genuine need, and to signal any occurence of such means having been operated, emergency locks are usually provided with a form of indicatorwhich changes state upon operation of those means. In priorart locksthis indicatoris in the form of a frangible member which must of necessity be broken when emergency unlocking takes place and the absence or broken condition of which constitutes the signal thatthe emergency means have been operated.In one arrangement currently available a thumbturn for emergency withdrawal of the lock bolt is covered by a frangible dome which must be smashed to enable access tothe turn; in another a lever handle is provided for emergencywithdrawal of the lock bolt and the handle extends out through an aperture in a frangible dome sothatturning the handle breaks the dome.

Thesefrangible indicatorsdo, however, havecer- tain drawbacks. For example, an unauthorised person having access to replacement indicators might open the doorfor clandestine purposes and then simply replace the broken indicator so thatthere will be no outward appearance of the door having been opened.

The use of frangible indicators also means that a stock of replacement indicators must be held by an appropriate authority and that it is necessary to break an indicator whenever the emergency operation of the lockistested.The needto breakthe indicatorfor emergency opening of the door can also to some persons act as an undesirale psychological barrier to escape even in the event of a real emergency.

Accordingly the present invention proposes an emergency lock provided with a handle for enabling withdrawal of the lock bolt in an emergency and a non-frangible mechanical indicator linked to the handle so as to move from a first position to a second position when the handle is movedto enable boltwithdrawal; and meansfor retaining the indicator in its second position when moved as aforesaid such as to preventreturn ofthe indicator to ìtsfirstposition by return movement of the handle or by force applied directlytothe indicator.

Such an arrangementtherefore avoids the use of frangible indicators. Furthermore, once the emergency handle has been operated the aforesaid indicator cannot be reset to its normal position without releasing the aforesaid retaining means, and it can be arrangedthatthis can only be achieved e.g. by use of a key or a special tool or by partially dismantling the assembly, so that unauthorised persons cannot readily return the indicator to a condition in which no indication of door-opening is given, if the emergency handle has been used to open the door for clandestine purposes.

The invention also resides in an item of door furniture, suitable for use with an emergency look, comprising a mounting plateforattachmentto a door; a handle borne bythe plate and adapted to be linked to a lockto enablewithdrawal of the bolt thereof; a non-frangible mechanical indicator borne bythe plate and linked to the handle so asto move from a first position to a second position when the handle is movedto enable bolt-withdrawal; and means borne by the plate for retaining the indicator in its second position wh en moved as aforesaid such as to prevent retu rn of the indicator to its fi rst position by retu rn movement of the handle or byforce applied directly to the indicator. Preferablythefurniture is arranged such that no access is available to said retaining means whenthefurniture isfullyassembled and attached to the door.

The invention will now be more particularly descri bed, by way of exam ple, with reference to the accompanying drawings, in which: Figure 1 is an internal elevation of a half-set of emergency doorfurniture made in accordance with one embodimentofthe invention; Figure 2 is an external elevation of half-set of emergency doorfurniture made in accordance with a second embodiment ofthe invention; Figure 3 is an internal elevation of part of the furnigure of Figure 2; and Figure 4 is a vertical cross-section through the furniture of Figures 1 and 2.

The fu rniture illustrated in Figure 1 is intended for use in conjunction with a mortice deadlock, the bolt of which can be withdrawn from either side of the door by a proper key and can be withdrawn only from the inside by a lever handle 1. This handle is journalled in a channel-shaped mounting plate 2, the reverse (i.e.

internal) face of which is viewed in the drawing. The shank 3 of the handle extends through the plate and is fitted internallywith the usual square-sectioned spindle 4extending into the lock assembly (not shown) for bolt-withdrawal . A stop washer 5 is also keyed onto the handle shankwithin the channel ofthe mounting platefor limiting the extent of handle movement and operating the indicatorto bedescribed below. The mounting plate isapertured at 6 to passa key.

Journalled in the plate2 above the handle 1 is the shank7 of an indicating memberwhich isformed on the external (i.e. exposed in use) face of the plate with an indicating finger 8. A plastics moulding 9 is also slidable with in the channel of the plate 2, above the washer 5 and alongside the indicator shank 7. This moulding has a slot 10 which in the normal, at-rest condition ofthe handle 1 illustrated in the drawing receives a cross-pin 11 fastened onto the indicator shank 7. This moulding or slide 10 is normally held in this position by a detent spring 12 mounted inside the plate 2 and engaging in a shallow depression 13 in the silde.

The handle 1 is only intended to be used to unlock the associated door in an emergency, and the purpose of the indicator 8 is to signal visually any occurrence of the handle having been operated. Its upright position illustrated in the drawing indicates that no such operation has occurred since itwas last inspected.If, however,the handle isturned (clockwise as viewed in the drawing) to with draw the lock bolt, the washer 5 is also turned so that a tang 14 on the washer engages the undersurface of the slide 9 and shifts the latter upwards to a position in which the detentspring 12 is pressed out ofthe depression 13 and snaps into a deeper recess 15 in the slide. Astheslide moves the cross-pin 11 is pressed out of the slot 1 0 and rotates the indicator 8 to a new angular position to indicate operation of the handle.Theslide9is retained in its raised position bathe spring 12 to keep the indicatorin its displaced condition, notwithstanding retu m of the handle 1 to it rest position. Furthermore, in this condition the end of the cross-pin now lies against the facr 16 ofthe slide below its slot 10, so no attemptto farce the indicator back upright will be capable of moving the slide downwards to release its blocking action on return movementofthe indicator.

To reset the indictor 8 the detent spring 12 must be released from the slide 9 and the latter pressed down to its initial position. When the furniture is assembled tothe door, however, the mounting plate 2 (and possibly also a channel-shaped face platesnapped over it) shields these components from access and the onlyway in which resetting can be achieved is by removing the furniture assemblyfromthe door.This furnituretherefore provides the desired indicating functionforan emergency lock while avoiding the use offrangible members, and without providing any ready meansfor unauthorised personsto operatethe emergency handle and then resetthe indicator.

Turningto Figures2-4,the illustrated furniture is again intended for use in conjunction with a mortice deadlock,the boltofwhich can bewithdrawn from eitherside ofthe doorby a proper key and can be withdrawn only from the inside by a lever handle 21.

This handle is journailed in a channel-shaped mounting plate 22, with its shank 23 extending thorough the plate and fitted internally with the usual squaresectioned spindle 24 extending into the lock assembly (notshown) for bolt-withdrawal. A stop washer 25 is also keyed onto the handle shank within the channel of the mounting plate for limiting the extend of handle movement and operating the indicatorto be described below. The mounting plate is apertured at 26 to pass a key.

Journalled in a plastics bush 27 above the handle 1 is a plastics indicating button 28 marked with an indicium 28A on its exposed head. Internallyofthe plate 22 a cam 29 is keyed onto the button 28 and pressedtowardsthewebofthe plate bya compression spring 30. The cam has tangs 31, 32 bent from it which contactthe plate and the lower one 32 of which lies in a shallow depression in the plate to define the normal angular position of the cam and button 28.

As before,the handle 21 is only intendedto be used to unlockthe associated door in an emergency and the purpose of the indicator 28 is to signal visuaTiy any occurrence of the handle having been operated.The horizontal position of its indicium illustrated in Figure 2 indicates that no such operation has occurred sirice it was last inspected.If, however, the handle is tu rned (clockwise as viewed in Fig u re 2 and anticlockwise as viewed in Figure 3) to withdraw the lock bolt, the washer25 is also turned sothatatang 33 on the washer engages the cam 29 and rotated the latter, and with itthe indicator28, to a new angular position to indicate operation of the handle. Inthisconditionthe tang 32 of the cam encounters an aperture 34 in the plate 22 and the cam tilts on the shank of the indicator 28 undertheforce of the spring 30 to engagethetang 32 in the aperture 34. The cam 29 and indicator28 are thus retained in the displaced condition notwithstanding return of the handle 21 to its rest position (under the action of a return spring 35). The engagement of the tang 32 in the plate aperture 34 will resist any attempttoforcethe indicator28 backto its normal position,theflush mounting of the indicator head in the bush 27 in any event making it difficult to apply any grip to the indicator for this purpose.

To reset the indicator 28 the cam 29 must be prised out oftheaperture 34 and turned backto its illustrated position. When the furnitur is assembled to the door, however, the mounting plate 22togetherwith a channel-shaped face plate 36 snapped over it shields the cam from access and the only way in which resetting can be achieved is byremovingthefurniture assemblyfrom the door. This furniture therefore a Iso providesthe desired indicating function foran emergency lockwhileavoiding the use of frangible members, and without providing any ready means for unauthorised persons to operate the emergency handle and then reset the indicator.

Claims (8)

1. A lock provided with a handle for enabling withdrawal of a bolt of the lock and a non-frangible mechanical indicator linked to the handle so as to move from a first position to a second position when the handle is moved to enable bolt-with drawal; and means for retaining the indicator in its second position when moved as aforesaid such asto prevent return of the indicator to its first position by return movement of the handle or by force applied directly to the indicator.

2. Doorfurniture comprising a mounting platefor attachmentto a door; a handle borne bathe plate and adapted to be linked to a lockto enable withdrawal of a boltthereof; a non-frangible mechanical indicator borne bythe plate and linked to the handle so as to move from a first position to a second position when the handle is moved to enable bolt-withdrwals and means borne bythe platefor retaining the indicatorin its second position when moved as aforesaid such as to prevent retu rn of the indicator to its first position by return movement of the handle or byforce applied directlytothe indicator.

3* Furniture according to claim 2 arranged such that no access is available to said retaining means when the furniture is fu lly assem bled and attached to a door.

4. À lock or furniture according to any preceding claim wherein the indicator is a rotary member which turnswith means having a projection which normally lies within a recess in a slide member; the slide member bering linked to the handle such that movement of the handle to enable bolt-with drawal drives the slide memberto a displaced position causing said projection to be driven out of said recesstoturn the indicatorfrom its first position to its second position, in which re-engagemant of said projection in said recess cannot be effected whiletheslide member remains in said displaced position.

5. A lock or furniture according to claim 4 including resilient detent means for retaining the slide member in said displaced position when driven as aforesaid.

6. A lock orfurniture according to any one of claims 1-3 wherein the indicator is a rotary member whichturnswithacam memberlinkedtothehandle such that movement of the handle to enable boltwithdrawal turnsthe cam memberto a displaced position causing the indicator to tu rn from its first position to its second position; means being provided to retain the cam mem ber in said displaced position.

7. A lock orfurniture according to claim 6wherein the indicatorandthe cam memberare bornecoaxially bya platewith the cam member disposed on the opposite side of the plate to the indicating portion of the indicator; the cam member is biased resiliently in the axial sense towards the plate and is capable of limited displacement in that sense relative to the indicator; and a portion of the cam member engages in a recess in the plate under said bias to retain the cam member in said displaced position when turned as aforesaid.

8. Doorfurniture according to claim 2 and substan tially as herein before descri bed with reference to Figure 1 or Figures 2-4 of the accompanying drawings.