AU600834B2

AU600834B2 - Improvements in security locks

Info

Publication number: AU600834B2
Application number: AU17662/88A
Authority: AU
Inventors: Graham James Luker
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-06-15
Filing date: 1988-06-14
Publication date: 1990-08-23
Anticipated expiration: 2008-06-14
Also published as: AU1766288A

Description

COMMONWEALTH OF AUSTRALIA PATENTS ACT, 1952 COMPLETE SPECIFICATION FOR OFFICE USE 600834 Short Title: InL. Cl.

Application Number: Lodged: Complete Specification Lodged Accepted: Lapsed: Published:; a Priority: Related Art: TO BE COMPLETED BY APPLICANT Name of Applicant: Graham James Luker Address of Applicant: 658 Port Hacking Road LILLI PILLI N.S.W. 2229 Actual Inventor: Graham James Luker Address for Service: ANDERSON-TAYLOR ASSOCIATES, Registered I Patent and Trade Mark Attoreys of Carina Road Oyster Bay N.S. 2225 Complete Specification for the invention entitledli 0 IMPROVEMENTS IN SECURITY LOCKS The following statement is a full description of tis invention -p including the best method c- performing it known o me:- -1a- 0- 0 £0 L1 This invention relates to security apparatus and more particularly to locks for emergency exit doors or the like.

Emergency exit doors naturally have to be readily opened from the inside and in large office buildings this has given rise to difficulties with staff control. In particular problems have arisen with employees leaving through such exits with,' t authorization during working hours to attend to personal business.

It is therefore an object of this invention to provide an improved lock mechanism for emergency exit doors or the t• like which while being readily releasable from the inside can nevertheless be sealed against unauthorized use. Other objects and advantages of the invention will become 4 apparent in the following description.

Broadly this invention discloses a lock mechanism for a door or the like, said mechanism comprising a tongue which in use is pivotable between an extended position J when said door is closed and a retracted position when said door is open and a pawl means adapted to releasably r j retain the tongue in said extended position to lock said door closed and when the tongue is released and the door is open said tongue is biased by a spring to said retracted position and said tongue further includes a recess which upon closing of the door is adapted to engage a rib in the strike of the door jamb to pivot said tongue back to Ac.AA I -2- T I its extended position within the strike plate.

one preferred embodiment o- this invention will now be described with reference to the attached representations in which: 00 0 0 ci ci ci 00 0 0 0 ci 000 0 o.

ci 0 ci 0,040 00 ci 0 o eno 000 .i 00 ci 0 0 00 00 a 0 00 00 ci 040 0 00 0 000 000000 0 ci

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-2a- Figure 1 shows perspective viewsof an assembled lock according to this invention, Figure 2 shows the lock of figure 1 with the cover removed, Figure 3 shows a cross-sectional view of this lock along the lines A-A of figure 2 with the tongue in its extended position, and Figure 4 shows a cross-sectional view of the lock along the lines A-A of figure 2 with the tongue in its retracted position.

o 04 00 0 o 03 o coo3 0* 0 0 0 O o a o 4 4 a 0 1 4000 o a Referring first to figure 1 the lock may comprise a removable cover 1 with a frangible front panel 2 and a pivotable tongue 3 extending through one side. The lock is mounted in the usual fashion against the inside of an outswinging door so that the tongue aligns with an adjacent strike plate 4 and a recess 5 in the tongue engages a rib 6 formed on this plate. Holes (not shown) may be provided in the rear face of the housing for mounting screws to hold it flush against the door with the breakable panel 2 facingl Qut~ward-y. Key operated cylinders 7 and 8 are also fitted into the opposite side and rear faces of the housing to enable the lock mechanism to be activated from either the inside or the outside through a corresponding aperture in the door as described later.

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0 O 0 So o o 0 00 0 CO O o 0 0 0 o 0 De o 0 00 o o

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0 04 0 (1 As best shown in figures 3 and 4 the tongue is mounted on a spindle 9 and is pivotable between an extended position in which it engages a rib 6 on an adjacent strike plate as mentioned earlier and a retracted position in which it clears this rib and allows the door to be opened. With this particular embodiment the tongue is releasably held in the extended or locked position by means of a pawl 10 mounted on a second spindle 11. One end 12 of this pawl is formed into a lug or prong which engages a niche 13 in the rear of the tongue 3. Depression of face 14 on this pawl however which is located directly behind breakable panel 2 pivots the prong 12 out of niche 13 and allows the tongue to rotate under the action of spring 15 to the retracted or open position. Alternatively the tongue can be released by rotating either of the key 1)perated cylinders which displace respective fingers 16 and 17 to pivot the pawl.

With this device installed on the inside of an emergency exit door it will be appreciated that while the barrier is effectively locked to unauthorised personnel on either side immediate evacuation is easily obtained simply by pressing in the breakable panel 2. This panel preferably has a film over the outer surface to prevent splintering and is scored on the inside to fracture along a predetermined line under only moderate pressure. The face 14 immediately behind is then simultaneously depressed to release the tongue which then retracts to clear the strike plate as the door is pushed open. The tongue i -4- 1-1_ remains biased to this retracted position by spring so that when the door is subsequently closed the recess is aligned to re-engage rib 6 as the tongue pivots back into its extended position within the strike plate.

Preferably this same spring 15 is also adapted to blase the pawl 10 to the locked position where it engages niche 13 in the tongue.

In addition to the aforementioned emergency procedure the two key operated cylinders 7 and 8 also allow authorized *oaf daat 4 0 4 personal to release the lock from either side of the ott, door without breaking panel 2. Indeed, maintenance of the o aalock including replacement of the breakable panel can conveniently be done with the door open as the tongue is o 4 held in its retracted position. When the door is subsequently closed the tongue is automatically rotated back to its extended position and locked by pawl 10 as mentioned earlier.

As an additional security measure it is proposed that a micro switch 18 be incorporated into the lock mechanism.

This switch would be closed by displacement of the pawl to its disengaged position and would activate either an internal alarm 19 powered by a battery 20 or alternatively a remote alarm located in another part of the building.

Further, a magnet and reed switch may be incorporated into V the tongue and stike plate which upon opening of the door also activates an alarm.

It will thus be appreciated that this invention at least in the form of the embodiment described provides a novel and unique security lock with a range of features and unobtrusive size not presently available. Clearly however the example disclosed is only one form of this invention and a wide variety of modifications may be made which would be apparent to a man skilled in the art. For example o o the shape and configuration of the housing, tongue and o pawl mechanism as well as the placement of the key operated cylinders may all be changed according to application or design preference.

64- -6- 0 tO

Claims

1. A lock mechanism for a door or the like, said mechanism j comprising a tongue which in use is pivotable between San extended position when said door is closed and a retracted position when said door is open and a pawl means adapted to releasably retain the tongue in said extended position to lock said door closed and when the tongue is released and the door is open said tongue is biased by a spring to said retracted position and said tongue further includes a recess which upon closing of 'the door is adapted to engage a rib in the strike of the door jamb to pivot said tongue back to its extended position within the strike plate.

2. The lock mechanism as claimed in claim 1 wherein the tongue is releasable by breaking a frangible panel. 4

3. The lock mechanism as claimed in claim 1 or 2 wherein key operated means are also provided for releasig-...said tongue.

4. The lock mechanism as claimed in any one of claims 1 to 3 wherein the pawl means is also biased by said spring to releasably retain the tongue in said extended position.

The lock mechanism as claimed in claim 4 -7- wherein a reed switch is incorporated into the tongue which is adapted to be tripped by a magnet in the strike plate and activate an alarm when the door is opened.

6. The lock mechanism as claimed in claim 5 wherein the alarm is incorporated into said lock mechanism.

7. The lock mechanism as claimed in claim 2 wherein said frangible panel is glass.

8. A lock mechanism for a door or the like, said lock being substantially as described herein with reference to the attached drawings. t 1 o II I" 0t Dated this day of Mk 7 1990 Graham James Luker By His Patent Attorney MICHAEL ANDERSON-TAYLOR .,1 y j