GB2278391A

GB2278391A - Plural key system for lockable emergency exit doors

Info

Publication number: GB2278391A
Application number: GB9310824A
Authority: GB
Inventors: Jonathan Mark Sheldon; James Robert Clarke
Original assignee: Castell Safety International Ltd
Current assignee: Castell Safety International Ltd
Priority date: 1993-05-26
Filing date: 1993-05-26
Publication date: 1994-11-30
Anticipated expiration: 2013-05-26
Also published as: GB9310824D0; GB2278391B

Abstract

Each of a plurality of emergency exit doors 13 allowing escape from an area inside a building has a locking device 22 actuable to prevent opening of the door and operable by a first key which is free only when the locking device 22 is activated and a second key which is free only when the locking device is deactivated. The locking devices 22 of the doors 13 constitute a series in which the second key of each locking device serves as the first key of the next, all the keys being different. The second key of the last locking device is essential to operation of control means eg an alarm to permit use of the said area. The locking device 22 cooperates with a latching bar 16 of a conventional crash bar release device 14. <IMAGE>

Description

Lockable Emergency Exit Doors Buildings (such as cinemas, theatres, concert halls, stadia, art galleries, historic houses, commercial premises, and offices) having one or more areas which are periodically open to the public are required to have emergency exit doors which allow the occupants to escape without hindrance in the event of an emergency such as a fire.

Conventional escape doors have a crash bar escape mechanism in which the pushing of a crash bar on the inside of the door causes longitudinal movement of a latching bar, thereby releasing it from engagement with a striker fixed to the doorway. Such doors, particularly large ones or double doors, provide an easy means of entry or escape for unauthorised persons and facilitate the theft of large pieces of valuable equipment such as computers.

For this reason, it is a known practice to lock emergency exit doors, against the advice of the Fire Authorities, when a building is not in use. The danger is that one or more of these doors may inadvertently be left locked when the building is in use, which constitutes a very grave hazard should a fire occur.

Electronic/electrical systems are available which centrally control automatic locking/unlocking of the emergency exit doors when required. These may be linked to an alarm system so as to ensure that the doors are unlocked before the building is used. Such electronic/electrical systems are expensive to install and are difficult to fit to existing emergency exit doors. They are also costly to maintain.

It would be desirable to be able to provide a mechanical means of ensuring that the emergency exit doors are locked when the building (or part open to the public) is closed and unlocked when the building (or part) is opened.

In one aspect the present invention provides a building including means for selectively inhibiting and permitting use of an area inside the building, and a plurality of emergency exit doors allowing escape from the said area, each emergency exit door having a locking device which is actuable to prevent opening of the door and which is operable by first and second keys, the first key being removable only when the locking device is activated and the second key being removable only when the locking device is deactivated, each locking device being a member of a series of such locking devices in which the second key of each locking device serves as the first key of the next locking device in the series, all the keys being different, and the second key of the last locking device of the series being essential to operation of the said means to permit use of the said area.

The last key may be used in a variety of ways to permit or enable use of the building or part of the building, depending on the nature of the building and its intended use. For instance, it could be used to disable an alarm system, turn on a lighting system, activate a cash till, raise a car park barrier, etc.

In another aspect, the invention provides an emergency exit door having a latching device which is mounted on the inside of the door and which is releasable by pushing from inside the door,the emergency exit door including a locking device which is actuable to prevent opening of the door and which is operable by first and second keys, the first key being removable only when the locking device is activated and the second key being removable only when the locking device is deactivated.

In a further aspect, the invention provides a lockable emergency release assembly for mounting on the inside of an emergency exit door, the assembly comprising a latching device which is adapted to be mounted on the inside of the door and which is releasable by pushing from inside the door, and a locking device which cooperates with the latching device and which is actuable to prevent release of the latching device, the locking device being operable by first and second keys, the first key being removable only when the locking device is activated and the second key being removable only when the locking device is deactivated.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic plan view of the ground floor of a building; Figure 2 is an elevation of an emergency exit door, from inside the building, also showing the associated doorway; Figure 3 is a part-sectioned elevation of a locking device, together with part of a latching device of the emergency exit door, on an enlarged scale; Figure 4 is a view of the locking device from below, in the direction of arrow IV in Figure 3; Figure 5 is a section through the latching device, taken on line V-V in Figure 3; Figure 5a shows a modification of the embodiment of Figure 5; Figures 6 to 8 are cut-away perspective views of the locking device, illustrating the unlocking sequence;; Figure 9 shows a locking device in another embodiment of the emergency exit door; Figure 10 is a part-sectional elevation of part of a modified locking device and latching device; Figure 11 is a part-sectional elevation of part of a further modified locking device and latching device; and Figure 12 is a view on line XII-XII in figure 11.

The building shown in Figure 1 has four walls 1 defining an enclosure, which may be roofed or may be surmounted by one or more storeys. The building also includes fences 2 defining a forecourt having a pedestrian access 3 and a vehicular access closable by a barrier 4 which can be raised and lowered automatically by a drive unit 6. The front wall 1 has main entrance doors 7 which can be locked and unlocked by a remote controlled unit 8. The building has a lighting system including interior lights 9 and an alarm system including detectors 11. A central control unit 12 controls the units 6 and 8, the lighting system, and the alarm system.The control unit 12 is switchable between (a) a building use permitting mode, in which the drive unit 6 is operable to open the vehicular access, the remote controlled unit 8 unlocks the entrance doors 7, the lighting system is powered, and the alarm system is disabled, and (b) a building use inhibiting mode, in which the drive unit 6 keeps the barrier 4 closed, the unit 8 locks the entrance doors 7 closed, the light system is disconnected from the power supply, and the alarm system is primed.

The building has emergency exit doors 13 which can be pushed open from the inside in the event of a fire or other emergency. In order to prevent unauthorised entry, each door 13 has a latching device 14 which is readily releasable by pushing. Such devices (e. g. those sold under the trade mark "BRITON") are well known and comprise longitudinally movable latching bars 16 (at least one) whose ends engage striking plates 17 fixed to the doorway 18,a crash bar 19 pivotally mounted so that it can be pushed towards the door, and a transmission unit 21 for converting the movement of the crash bar 19 into longitudinal movement of the latching bars 16 so as to disengage them from the striking plates 17.

Each door 13 also has a locking device 22 which is actuable to prevent opening of the door. As best seen in Figure 3, the locking device 22 has a longitudinally movable bolt 23 which, when the device is activated, extends into the path of movement of an abutment 24 provided on one of the latching bars 16, thereby preventing longitudinal movement (disengagement) of at least this latching bar 16. The abutment 24 comprises a U-shaped element (Figure 5) which embraces the latching bar 16 and is fixed to it by a tension pin 26 which passes through it and extends into oblique bores 27 in the respective arms of the abutment 24. Figure 5a shows an annular abutment 24a.

The locking device 22 has a housing 28 which covers the abutment 24 and which mounts first and second locks 29a,29b for receiving first and second keys 31a,31b respectively. The locking device is of the type known as a bolt interlock, such as is sold, for example, under the trade mark "KL" by Castell Safety International Limited.

Referring to Figures 6 to 8: in the activated state of the locking device 22 (Figure 6) the bolt 23 is extended, the first key 31a is free, and the second key 31b is trapped in its receiver 29b; in a transitional state (Figure 7) the first key 31a is inserted into its receiver 29a and turned clockwise, the second key 31b is turned, thereby retracting the bolt, and is then removed from its receiver 29b; in the deactivated state (Figure 8) the bolt 23 is retracted, the first key 31a is trapped in its receiver 29a, and the second key 31b is free.

The locking devices 22 of the emergency exit doors 13, taken in a logical sequence (e.g. clockwise order starting near the entrance), constitute a series in which the second key of each locking device serves as the first key of the next locking device in the series, all the keys being coded differently. The initial key of the sequence (i.e. the first key of the first locking device in the series) and the final key of the sequence (i.e.

the second key of the last locking device in the series) are used to operate switches on the central control unit 12, so that the initial key is necessary to operation of the control unit in the above-mentioned building use inhibiting mode and the final key is necessary to operation of the control unit in the use permitting mode.

Thus it can be ensured that use of the building is prevented until all the emergency exit doors 13 have been unlocked in sequence, thereby releasing the final key.

Conversely, when the building is closed, the use permitting mode is cancelled and the final key is removed from the control unit 12 (which is therefore in a neutral state intermediate the permitting and inhibiting modes), the doors 13 are locked in reverse sequence, and the initial key is released, thereby allowing the control unit to be switched to the use inhibiting mode only after all the doors 13 have been secured.

Various modifications may be made within the scope of the invention. For instance, in a modified embodiment of the emergency exit door 13', as shown in Figure 9, there is a modified locking device 22' which is independent of the latching device. In this embodiment the bolt 23 engages in a hole 32 in a striking plate 33 fixed on the doorway 18.

As shown in Figure 10, instead of an embracing abutment 24 (Figure 3), the bolt 23 may engage in a recess 41 in an insert 42 having upper and lower spigots 43 inserted in upper and lower sections of a tubular latching bar 16 and held there by pins 44.

As shown in Figures 11 and 12, the bolt 23 may be extended beyond the insert 42 so as to be engageable in a hole 32 in a striking plate 33 fixed to the door frame.

Thus the door can be locked to the frame and the latching mechanism can be locked simultaneously, thereby enhancing security.

The above-mentioned series of locking devices may include one or more locking devices which are not associated with emergency exit doors.

There may be more than one series of locking devices (and associated emergency exit doors) so that use of one or more areas or zones of a building may be selectively inhibited and permitted, independently of other areas.

Claims

Claims: -

1. A building including means for selectively inhibiting and permitting use of an area inside the building, and a plurality of emergency exit doors allowing escape from the said area, each emergency exit door having a locking device which is actuable to prevent opening of the door and which is operable by first and second keys, the first key being removable only when the locking device is activated and the second key being removable only when the locking device is deactivated, each locking device being a member of a series of such locking devices in which the second key of each locking device serves as the first key of the next locking device in the series, all the keys being different, and the second key of the last locking device of the series being essential to operation of the said means to permit use of the said area.

2. A building as claimed in claim 1, in which the first key of the first locking device in the series is essential to operation of the said means to inhibit use of the said area.

3. A building as claimed in claim 1 or 2, in which the said means comprises an alarm system.

4. An emergency exit door having a latching device which is mounted on the inside of the door and which is releasable by pushing from inside the door,the emergency exit door including a locking device which is actuable to prevent opening of the door and which is operable by first and second keys, the first key being removable only when the locking device is activated and the second key being removable only when the locking device is deactivated.

5. An emergency exit door as claimed in claim 4, in which the locking device, when activated, prevents release of the latching device.

6. An emergency exit door as claimed in claim 5, in which the latching device comprises a longitudinally movable latching bar, a crash member which can be moved towards the door by pushing, and transmission means for converting movement of the crash member into longitudinal movement of the latching bar, the locking device, when activated, preventing longitudinal movement of the latching bar.

7. An emergency exit door as claimed in claim 6, in which the locking device cooperates with an abutment on the latching bar.

8. An emergency exit door as claimed in claim 7, in which the locking device includes a bolt movable into and out of the path of movement of the abutment.

9. An emergency exit door as claimed in claim 8, in which the bolt is movable to an extended position in which it projects beyond the door so as to be engageable with a striker in a doorway.

10. An emergency exit door as claimed in any of claims 7 to 9, in which the locking device has a housing which covers the abutment on the latching bar.

11. An emergency exit door as claimed in any of claims 7 to 10, in which the abutment is constituted by a U-shaped or annular element which embraces the latching bar and is fixed thereto, e. g. by an elongate fixing element which passes through the latching bar and extends into both arms of the U-shaped element.

12. An emergency exit door as claimed in any of claims 7 to 10, in which the abutment is constituted by an insert located between longitudinal sections of the latching door.

13. A lockable emergency release assembly for mounting on the inside of an emergency exit door, the assembly comprising a latching device which is adapted to be mounted on the inside of the door and which is releasable by pushing from inside the door, and a locking device which cooperates with the latching device and which is actuable to prevent release of the latching device, the locking device being operable by first and second keys, the first key being removable only when the locking device is activated and the second key being removable only when the locking device is deactivated.

14. A building including emergency exit doors, substantially as described with reference to any of the embodiments illustrated in the accompanying drawings.

15. An emergency exit door substantially as described with reference to any of the embodiments illustrated in the accompanying drawings.

16. A lockable emergency release assembly for an emergency exit door, substantially as described with reference to, and as shown in, Figures 2 to 8, Figure 10, or Figures 11 and 12 of the accompanying drawings.