GB2280474A

GB2280474A - Locking system for doors

Info

Publication number: GB2280474A
Application number: GB9415367A
Authority: GB
Inventors: David William Mcmorran; Granville Griffiths
Original assignee: ACCENT GROUP Ltd
Current assignee: ACCENT GROUP Ltd
Priority date: 1993-07-29
Filing date: 1994-07-29
Publication date: 1995-02-01
Also published as: GB9315683D0; GB9415367D0

Abstract

A locking system (1) for a door, comprises a primary mechanism (5) and a secondary mechanism (10). The primary mechanism (5) includes a plurality of bolts (11) and actuation means such as linkage rods (7, 7') for common actuation of bolts (11). A secondary mechanism (10) is provided so as to be selectively operable to disable actuation means (7, 7') of the primary mechanism, and to provide an additional locking bolt for the system. An example secondary mechanism is a deadlock (11') which extends through an aperture in a linkage rod to disable the primary mechanism. <IMAGE>

Description

DOORS The present invention relates to doors and locking systems therefor. The invention finds particular, but not exclusive, use in relation to doors for high security applications.

Commercial premises face an increasing threat from break in. To overcome such problems there is a desire to provide security doors which have strong bodies to resist forced entry. In particular, the bodies are required to resist penetration by high powered tools such as disc grinders and the like. Suitably, such security doors are made of co-extensive metal skins, having an appropriate filling material sandwiched between them.

In addition to resisting penetration by attack to the body of the door, it is also necessary to employ strong locking systems for securing a door to a jamb when in a closed position. Suitable locking systems can include a plurality of bolts spaced apart along the length of the free edge of a major surface of the door and adapted to selectively protrude therefrom to engage in a door jamb.

However, in addition to the security aspect for resisting unauthorised entry into a building, there are also safety considerations to be taken into account with regard to authorised occupants of a building. In this regard, there is a demand for doors which can be secured against break-in and yet which can be readily opened from the inside by authorised personnel in emergencies. Such doors are required for, in particular, commercial premises such as shops, banks, building societies, etc.

Thus, it is desirable to provide a balance between effective security against break-in and yet permit prompt escape for employees in an emergency.

With this in mind, multi-bolt locking systems exist which include a series of bolts and a linkage arranged between them to allow for effectively simultaneous projection/withdrawal of the bolts by operation of a handle on the inside surface of the door. This is advantageous because, by employing several bolts, this provides effective securement of a door to the jamb. In addition, the mechanism allows for essentially simultaneous release of all the bolts and thus can be opened very quickly in an emergency.

Whilst such mechanisms have advantages from the point of view of safety for authorised occupants of a building, they also pose a security risk. This is on the grounds that, irrespective of how strong a door body is, or how effective the bolts are in securing the door to the jamb, if a burglar gains entry to a building from another weak point (e.g. through a window), once in the building they can readily release all the security bolts to open the door. As a result, they can readily escape from the building taking valuables with them.

Thus, there are problems with existing security doors and locking systems therefor.

The present invention seeks to alleviate at least some of the aforementioned problems by providing alternative locking systems for a door.

Accordingly, with this object in mind, in one aspect the present invention provides a locking system for a door, the system comprising a primary mechanism which includes a plurality of bolts and actuation means for common actuation of said bolts, and a secondary locking mechanism selectively operable to disable said actuation means and to provide a secondary locking bolt for the system.

Thus, the present invention seeks to overcome the disadvantages of the previous multi-bolt locking systems by providing a secondary locking mechanism which may be selectively employed (e.g. especially at night or when a building is empty) to enhance security. Alternatively, the secondary mechanism may be released to permit ready withdrawal of the multi-bolt mechanism in an emergency.

Preferably, indication means are provided for indicating that the secondary mechanism is in operation.

Thus, in preferred embodiments, a visual indicator, such as a lamp or similar, is actuated when the secondary mechanism is used. This is preferred since it provides a signal to authorised occupants of the building that escape from the building may be inhibited.

Alternatively, or in addition, the secondary mechanism may be arranged to communicate with a component in an alarm system.

In some preferred embodiments, the secondary mechanism may be adapted to be operable remotely with electrical assistance.

In preferred embodiments, for securing the door to a jamb, the primary mechanism includes a plurality of bolts which are presented at the free edge of the major surface of the door and spaced apart along its length.

It will be appreciated that any number of bolts may be employed, as desired.

Suitably, the actuation means of the primary mechanism includes a connecting linkage which is capable of transmitting an opening movement to each door bolt, to effect essentially simultaneous projection and retraction of the bolts. A preferred example linkage may include a rod-type connection which is axially moveable to transmit the opening movement and to actuate displacement of the bolts.

Preferably, the actuation means of the primary mechanism includes a manual operating member to effect displacement of the bolts. For security reasons, preferably any operating members are provided only on the internal surface of the door. In preferred embodiments, such a manual operating member is conveniently arranged so that operation of the member effects displacement of linkage such as a rod type connection which, in turn, effects projection or retraction of at least some of the bolts of the primary mechanism. Example operating members are rotatable handles and push bars.

In particularly preferred embodiments, a main lock module is provided which communicates with one or more so-called slave lock modules, via one or more connecting linkage as described above. The mechanism is suitably arranged such that the manual operating member will actuate the main lock module and effect displacement of the connecting linkage to transmit the opening movement to the slave lock modules.

Typically, the actuation means of the primary lock mechanism and the secondary lock mechanism are arranged to interengage via a connecting linkage so that the secondary lock mechanism inhibits transmission of the opening movement to the bolts. In preferred embodiments, the secondary mechanism is a deadlock, which is operable with a key to both engage the primary mechanism and to provide a secondary locking bolt for the system.

Suitably, the actuation means includes a displaceable rod-type linkage as described, and which is apertured to allow passage of a bolt from the secondary mechanism therethrough, so that the bolt will obstruct displacement of the linkage and thereby disable the primary mechanism.

For embodiments which employ a manual operating member and connecting linkage in the actuation means for the primary locking mechanism, preferably means are also provided for selectively disabling the operating member when the secondary locking mechanism is in operation.

Particularly preferred embodiments which employ a handle as an operating member include means for disabling the handle once torque loading on the handle exceeds a predetermined level when the secondary locking mechanism is in operation. This is to prevent unauthorised persons applying source to the handle and to the connecting linkage in such a way as to distort the bolt of the secondary mechanism, thereby causing this mechanism to fail. An example locking system includes an operating cam-plate in the actuation means for the primary mechanism which is adapted to distort when subjected to high torque loading. Once the cam-plate distorts the handle is no longer capable of transmitting an opening movement to the connecting linkage.

Preferably, the locking system is housed in a casing of channel section, otherwise known as a mullion. In use, the mullion is generally secured to the internal major surface of the door, at or near the free edge of the door. This is advantageous in that, particularly in the case where the mullion is made of hardened steel or the like, the metal layers of the mullion help to strengthen the door to resist attack. Furthermore, it avoids the need for making holes in the door for accommodating locks, which is disadvantageous in that it weakens the door body.

In cases where a mullion is employed, the edge face of the mullion which, in use, will be alongside the door jamb, is apertured to allow the bolt of the secondary locking mechanism to project therethrough to engage the jamb.

In another aspect, the present invention concerns doors provided with such locking systems.

Embodiments of the present invention will now be described in more detail, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a schematic cross-sectional view of an example locking system; and Fig. 2 is a schematic perspective view of a part of the locking system, shown to an enlarged scale.

Turning to the drawings, Fig. 1 shows a locking system (1) comprising a primary mechanism (5) and a secondary mechanism (10). In more detail, the primary mechanism (5) comprises an actuation means including linkage rods (7,7') connecting a main lock module (8) to two slave lock module (17,17') respectively.

The illustrated main lock module (8) accommodates four bolts (11) and a latch (12). A manual operating member in the form of handle (9) is provided for actuating displacement of the bolts (11) and latch (12) of the main lock module (8). This is effected via a conventional mechanism which need not be described in detail for the present purposes.

The main lock module (8) communicates to slave lock modules (17,17') via linkage rods (7,7'), as described above. Each slave lock module (17,17') includes three bolts (11). The lock modules (8,17,17') and linkages (7,7') are all housed in a mullion (14). A face of the mullion (14) is provided with appropriate apertures to allow passage of bolts (11) and latch (12) therethrough for engagement in a door jamb. The mullion (14) will be secured to a major surface of a door, at or near its free edge.

In use, rotation of handle (9) is effective to displace bolts (11) and latch (12) from the main lock module (8). It also displaces the linkage rods by drawing rod (7) upwardly and rod (7') downwardly to effect essentially simultaneous displacement of bolts (11) in slave lock modules (17,17').

It will be appreciated that, in the illustrated embodiment, a plurality of bolts (11) are actuable at essentially the same time by turning handle (9). As discussed above, a disadvantage with this arrangement is that, if an unauthorised person gains access to the handle (9), they are able to effect release of all bolts (11) and latch (12) to thereby unlock the door and facilitate escape from the building.

The present invention addresses this problem by providing a secondary locking mechanism which is capable of disabling the actuation means for the first locking mechanism and of providing a secondary locking bolt for the system. In more detail, the secondary mechanism comprises a deadlock (10) provided with a bolt (11'). In this respect, various deadlocks (10) of conventional construction may be employed and need not be described in great detail for the present purposes.

Adjacent to the deadlock bolt (11'), an aperture (24) is provided in the mullion (14) to allow passage of the bolt (11') therethrough. A matching aperture (27) is also provided in linkage rod (7'). This is illustrated in more detail in Fig. 2.

Thus, in use, the secondary mechanism (10) may be operated with a key to actuate release of bolt (11) to project through aperture (27) in the linkage rod (7') and through aperture (24) in the mullion (14). In this way, the bolt (11') is available for engagement with a door jamb to enhance securement of the door to the jamb.

Also, the bolt (11') disables the primary locking mechanism by preventing displacement of rod (7').

Since release of bolt (11') can only be effected with an appropriate key for deadlock (10), the illustrated arrangement is much more secure against break-in than previous alternatives. This is on the grounds that the key for release of the deadlock will only be available to authorised personnel.

Various modifications of the illustrated embodiment are possible. For example, any number of secondary mechanisms may be employed and each such mechanism may include a plurality of bolts. In addition, the number of bolts for the primary mechanism may be varied to suit appropriate security requirements. Likewise, location of bolts with respect to the door and configuration of the particular bolts may be altered, as appropriate.

In addition, various alternative linkages may be employed to effect controlled release of the bolts and the invention is not limited to the rod type linkages illustrated.

Furthermore, it is also desirable to modify the illustrated embodiment to include indicator means, in order to show that the deadlock (10) is in operation. An example would be to provide a microswitch, which is switched on as the deadlock is used, to actuate a lamp or other visual indicator for example. Alternatively or in addition the microswitch could form part of an alarm system. In this way, authorised occupants in a building can recognise that the deadlock is in use and release it during the daytime, for example.

Also, the door may be adapted so that the deadlock is operable only from inside the building or from both inside and outside, if desired.

A further alternative to the illustrated embodiment concerns the provision of means for disabling the operating member when the secondary locking mechanism is in operation. For example, problems may arise when the bolt of the secondary mechanism obstructs displacement of the connecting linkage for the first locking mechanism.

It is possible for unauthorised persons to apply excessive force to the handle for the first locking mechanism in an attempt to effect some movement of the linkage and to buckle the locking bolt for the secondary mechanism. This may result in release of the secondary locking mechanism, to permit the door to be-opened upon operation of the primary locking mechanism.

As an example solution to this problem an operating cam-plate for the operating handle of the primary mechanism may be designed in such a manner as to distort when subjected to the high torque loading, such as would be typical in the above situation. Once the cam-plate distorts, the handle can no longer apply movement to the linkage in the locking mechanism, protecting all other components from further abuse but still allowing operation of the door by authorised key-holders.

Claims

CLAIMS:

1. A locking system for a door, the system comprising a primary locking mechanism which includes a plurality of bolts and actuation means for common actuation of said bolts, and a secondary locking mechanism selectively operable to disable said actuation means and to provide a secondary locking bolt for the system.

2. A locking system according to Claim 1 wherein the actuation means of the primary mechanism includes a connecting linkage which is capable of transmitting an opening movement to each door bolt of the primary mechanism, to effect essentially simultaneous projection and retraction of the bolts.

3. A locking system according to Claim 1 or 2 wherein the primary locking mechanism comprises a main lock module which communicates with one or more slave lock modules via a connecting linkage to actuate the main lock module and to effect displacement of the connecting linkage to transmit the opening movement to the or each slave lock module.

4. A locking system according to Claim 2 or 3 wherein the actuation means of the primary mechanism is arranged to interengage with the secondary mechanism so that the secondary mechanism inhibits transmission of the opening movement to the bolts of the primary mechanism.

5. A locking system according to claim 4 wherein the secondary mechanism includes a deadlock, which is operable with a key to both engage the actuation means of the primary mechanism and to provide a secondary locking bolt for the system.

6. A locking system according to any one of claims 3 to 5 wherein the actuation means of the primary locking mechanism is a linkage which is axially movable to transmit an opening movement and to actuate displacement of the primary mechanism bolts.

7. A locking system according to Claim 6 wherein the actuation means of the primary mechanism includes a linkage and which is apertured to allow passage of a bolt from the secondary mechanism therethrough, so that the bolt will obstruct displacement of the linkage and thereby disable the primary mechanism.

8. A locking system according to any preceding claim wherein the actuation means of the primary mechanism includes a manual operating member to effect displacement of the bolts.

9. A locking system according to Claim 8 having means for selectively disabling the manual operating member when the secondary locking mechanism is in operation.

10. A locking system according to any preceding claim wherein the secondary mechanism is adapted to be operable remotely with electrical systems.

11. A locking system according to any preceding claim having indication means for indicating that the secondary mechanism is in operation.

12. A locking system according to any preceding claim housed in a casing of channel section.

13. A locking system substantially as hereinbefore described with reference to, and as illustrated in, any one of the accompanying drawings.

14. A door provided with a locking system as claimed in any preceding claim.

15. A door according to Claim 14 provided with a locking system of claim 11 wherein the casing is secured to a major surface of a door at or near its free edge.

16. A door accordingly to Claim 15 or 15 wherein the actuation means of the primary mechanism includes a manual operating member arranged at one major surface of the door.