GB2154651A

GB2154651A - Key-operated security mechanism

Info

Publication number: GB2154651A
Application number: GB08503579A
Authority: GB
Inventors: Alan Critchley
Original assignee: Shorrock Security Systems Ltd
Current assignee: Shorrock Security Systems Ltd
Priority date: 1984-02-17
Filing date: 1985-02-12
Publication date: 1985-09-11
Also published as: GB8503579D0; GB8404271D0; GB2154651B

Abstract

To combine the operation of locking a container 10 with switching on and off equipment inside the container, bolt element 11 inside the container 10 is movable, by a key 15 inserted from outside, between a first position (not shown) in which equipment switch 16 is actuated and a second position (not shown) in which it is not. In both positions the container 10 is locked by engagement of the bolt element 11 with a locking member 17. The element 11 is also movable to a third position (Fig. 2) in which the equipment is switched off and the container lid 13 can be opened. <IMAGE>

Description

SPECIFICATION Key-operated security mechanism This invention relates to a key-operated mechanism for an enclosure.

Access to the inside of a container, such as an alarm control unit, is usually by high security means to discourage unauthorised persons from tampering with equipment in side the container. Accordingly, such access can usuaily only be gained by means of a key operated locking mechanism. However, simi lar high security means are generally provided for switching on and off the equipment, e.g.

alarm control equipment, inside the container.

it is an object of the present invention to combine the two operations of locking a container and switching on and off equipment inside the container in one mechanism.

Pursuant hereto the present invention provides a key-operated mechanism for an enclosure comprising an element disposed inside the enclosure which is caused to move, by virtue of a key inserted from outside the enclosure, between a first position in which equipment disposed inside the enclosure is activated and a second position in which said equipment is inactivated, the same element also being movable, by virtue of the key, to a third position in which it releases a door or lid of the enclosure so that the latter can be opened.

The third position of the element is conveniently arranged between the first and second positions thereof.

Preferably, the key cannot be removed from the mechanism when the element is in the third position and the door or lid is released.

This minimises the likelihood of the door or lid being left unlocked since an operative is unlikely to leave his/her key in the mechanism and if a key is thus left it is readily noticeable.

In a particularly simple embodiment of the mechanism, which is easy to construct and is not prone to mechanical failure, the movable element inside the enclosure is in the form of a rotatable plate which is engageable with a lever-operated micro-switch of the equipment, e.g. alarm control equipment, so as to activate the latter. The plate may be attached to the door or lid of the enclosure and be engageable with a locking member provided on a wall defining the enclosure to effect locking of the door or lid. Alternatively, the plate may be attached to the wall and engageable with a locking member on the door or lid.

The plate is conveniently shaped as a circle with particular segments or sectors cut away, the equipment being activated when a portion of the plate engages the lever-operated microswitch and being inactivated when the plate is rotated so that a cut away segment or sector overlies the micro-switch. In a similar manner, the door or lid will be locked when the plate engages the locking member, and released when a cut away segment or sector is in alignment with the locking member.

The invention will be described further, by way of example with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic cross-secton of a container incorporating one embodiment of the mechanism of the invention; Figure 2 is a partial cross-section along the line ll-ll shown in Fig. 1 with the plate in the 90 position; Figure 3 is a similar view to Fig. 2 with the plate in the 0 position; Figure 4 is a similar view to Fig. 2 with the plate in the 180 position; and Figure 5 is a similar view to Fig. 2 of a modified embodiment of the mechanism of the invention.

A first embodiment of the invention is shown in Figs. 1 to 4 applied to an enclosure defined by a container 10 having a hinged lid 13. A D-shaped plate 11, that is to say a plate shaped as a circle with a large segment cut away, is attached inside the container 10 to a key-operated lock 1 2 which extends through the lid 1 3. The lock 1 2 and the plate 11 attached thereto are located adjacent the edge of the lid 1 3 opposite the hinge 14.

The lock 1 2 is rotatable through 180 and is of the type where the key 15, insertable from outside the container 10, can only be removed in either of two extreme positions, at 0 and 180 , which are illustrated in Figs. 3 and 4 respectively. In the 0 position, as shown in Fig. 3, an alarm control (not shown) located inside the container 10 is activated and in the 180 position, as shown in Fig. 4, the alarm control is inactivated. The change, or rather the switching on and off the alarm control, is brought about by operation of a switch 16.The switch 16 in this case is a lever-operated micro-switch and due to the relative positions of the D-shaped plate 11 and the switch 16, the lever is depressed by the plate 11 when in its 0" position so as to activate the alarm control and is released when the plate 11 moves to its 180 position so that the alarm control is inactivated.

In both 0" and 180 positions, the plate 11 is physically located beneath a locking member in the form of a clip 1 7 on the edge of the container 10 so that opening of the lid 1 3 is prevented.

When the key 1 5 is rotated to the 90 position, the plate 11 rotates likewise to the position shown in Fig. 5 thus clearing the lip 1 7 and allowing the lid 1 3 to be opened. It should be noted, however, that the key 1 5 cannot be removed in this 90 position, and the alarm control is, of course, inactivated since in this position the plate 11 does not engage the lever of the microswitch 16.

To prevent the lid 1 3 inadvertently swinging open every time the plate 11 is moved by the key-operated lock 12 between the 0" and 180 positions (i.e. the on and off condition of the alarm control), a screw 1 8 may be provided to hold the lid 1 3 against the lip 1 7.

This screw 1 8 can, of course, easily be removed when the lid 1 3 is to be opened.

In summary, in the 0 position of the plate 11, the alarm control is switched on, the lid 1 3 is locked and the key 1 5 can be removed; in the 90 position, the alarm control is switched off, the lid 1 3 is openeable but the key 1 5 cannot be removed from the lock 12; in the 180 position, the alarm control is switched off, the lid 1 3 is locked and again the key 15 can be removed.

Although the embodiment just described includes a D-shaped plate 11 and a container lip 1 7 as the movable element and the locking member respectively, many variants are possible. For example, if a 90 rotation lock is used (instead of a 180 lock as in the previous embodiment), the plate could be shaped as a circle with a 90 segment cut away, as shown in Fig. 5, with the lid openeable at 45'.

In like manner, whilst a lever-operated micro-switch is shown as the alarm control on/off switch in the illustrated embodiments, a possible non-contact alternative could be obtained by suitably positioning a magnet on the plate to operate a reed switch in the on position.

Claims

1. A key-operated mechanism for an enclosure comprising an element disposed inside the enclosure which is caused to move, by virtue of a key inserted from outside the enclosure, between a first position in which equipment disposed inside the enclosure is activated and a second position in which said equipment is inactivated, the same element also being movable, by virtue of the key, to a third position in which it releases a door or lid of the enclosure so that the latter can be opened.

2. A mechanism as claimed in claim 1 wherein the third position of the element is arranged between the first and second positions thereof.

3. A mechanism as claimed in claim 1 or 2 wherein the key cannot be removed from the mechanism when the element is in the third position and the door or lid is released.

4. A mechanism as claimed in claim 1, 2 or 3 wherein the movable element inside the enclosure is in the form of a rotatable plate which actuates a switch of the equipment in the first position but not in the second or third positions.

5. A mechanism as claimed in claim 4 wherein the plate is attached to a door or lid of the enclosure and, in the first and second positions at least, is engageable with a locking member provided on a wall defining the enclosure to effect locking of the door or lid.

6. A mechanism as claimed in claim 4 or 5 wherein the plate is shaped as a circle with particular segments or sectors cut away.

7. A mechanism as claimed in claim 4, 5 or 6 wherein the switch of the equipment is a lever-operated micro-switch actuated by engagement of the plate with the lever.

8. A mechanism as claimed in claim 4, 5 or 6 wherein the switch of the equipment is a reed switch actuated by proximity of a magnet mounted on the plate.

9. A key-operated mechanism substantially as hereinbefore described with reference to and as illustrated in Figs. 1 to 4, or Fig. 5 of the accompanying drawings.