GB2224536A - A key-actuated operating mechanism - Google Patents

Abstract

An operating mechanism for a switch, valve, or lock (a lock is depicted) is provided with an axial passageway 42 which is defined by a guard member 44 and an actuator 16 disposed at one end of the passageway. The actuator is of cylindrical construction and includes an annular channel 34 in which a stop 36 is disposed. A special key 18 which has two jointed portions 20, 22 is used to turn the actuator 16. Upon insertion through the passageway 42, the portion 22 drops under its own weight and subsequent rotation of the key forces the portion 22 against the stop 36 thus rotating the actuator 16. <IMAGE>

Description

A KEY-ACTUATED OPERATING MECHANISM This invention relates to an operating mechanism having an actuator for engagement by a key. Such a mechanism may be used for opening and/or closing a switch or a fluid valve or for releasing a lock, for example.

Simple locks, designed to receive various standard keys carried by the emergency services (for example ambulance or fire services) are well known and are used, for example, in fire doors in blocks of flats etc. which are normally not used but through which urgent access may be required. Locks of this type generally comprise a shaped key which is simply inserted into the lock and turned, thus operating the lock release mechanism to open the door. However, such locks can easily be 'picked' by use of, for example, a suitably dimensioned screwdriver or other tool and it is thus a problem that unauthorised use of such doors may easily be effected, compromising the security of buildings having such locks. Similar problems arise with the operating mechanisms of switches and valves, which are open to abuse.

The present invention provides an operating mechanism comprising an actuator for engagement by a key, and a guard member extending through the mechanism and defining a passageway through which a said key is insertable from one end of the passageway, the actuator being disposed at the other end of the passageway.

The provision of a guard member defining the passageway through which the key is inserted provides protection for the operable components of the mechanism over the width of the door in which the lock is disposed, thus making it considerably more difficult for an unauthorised person to tamper with the mechanism.

The actuator is preferably rotatable and preferably has an annular channel in which a stop is disposed. This construction provides particular protection against use of a bicycle chain, for example, for opening the lock.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a sectional view of a lock including an operating mechanism in which a key is engaged; Figure 2a is a side view of the key shown; and inure 2b is a view in te direction of arrow A in Figure 2a.

In Figure 1 a lock is shown mounted in a door 10 or other partition. The lock includes a main lock mechanism 12, which includes retractable bolts (not shown) for engagement with a door frame. The lock mechanism 12 is connected, via transmission gear 14, which may comprise, for example, gears or levers for operating the lock mechanism, to an operating mechanism serving as a lock release mechanism which comprises an actuator 16, which, in use, engages with a key 18 for operation of the lock.

The key, shown more clearly in Figures 2a,2b has a T-bar shaped handle 20, the shank 21 of the T being of elongate cylindrical form, and an engagement member 22 which is hingably connected to the handle 20 by means of a pin 24, so that the lock engagement member 22 can rotate from the position shown in phantom lines in Figure 2a to that shown in full lines.

The actuator 16 includes a hollow cylindrical portion 30, connected to the lock transmission gear 14, and a disc 32 of sufficient size to be used as an internal handle for operating the lock. The disc 32 is provided with an annular channel 34 open to the inside of the door and a narrow stop 36 disposed on the outer circumferential edge of the channel. The stop 36 is arranged to be disposed at the uppermost position of the channel, when the lock is engaged. In Figure 1, the lock is shown in the open position.

The engagement member 22 of the key and the channel 34 have complementary cross sections so that the engagement member 22 can lie in the channel as shown in Fig. 1 and, when not engaged with the stop 36, be rotated freely therein by turning the key handle.

The driving gear 14 and actuator 30 are together mounted in a generally cylindrical lock support 40 which is attached to the door 10. The lock support 40 is provided with a passage from the inside to the outside of the door within which a hollow cylindrical guard member 44 is disposed as a lining defining a passageway 42. A steel cover plate 46 is mounted around the outside opening of the cylindrical passageway 42.

In use, the key 18 is inserted from the outside through the passageway 42 until the engagement member 22 clears the inside end 45 of the passageway 42. At this point the engagement member 22 of the key 18 will drop, under its own weight, into the position shown in Figure 1 in which the engagement member 22 is disposed in the channel 34. koraEion Cf the key will ten force the member 22 up against stop 36 causing the actuator 16 to rotate, thus releasing the lock.

Once the door has been opened, the engagement member 22 of the key 18 can be raised and the key withdrawn, by pulling the key handle 20.

Although the key is shown as engaging a stop disposed within a channel, this is not to be construed as limitative and the engagement member 22, provided this is no wider than the passageway 42, could be provided with a projection engaging a correspondingly shaped recess formed in the actuator 16. Furthermore, the stop 36 may be disposed on a planar face rather than in a channel.

Claims (13)

CLAIMS:

1. An operating mechanism comprising an actuator for engagement by a key. and a guard member extending through the mechanism and defining a passageway through which a said key is insertable from one end of the passageway, the actuator being disposed at the other end of the passageway.

2. A mechanism as claimed in claim 1, in which the actuator is rotatable and has a formation adapted to engage a said key. the formation being disposed radially outwardly of the passageway.

3. A mechanism as claimed in claim 2, in which the formation comprises a stop.

4. A mechanism as claimed in claim 3, in which the actuator includes an annular channel, the stop being disposed in the channel.

5. A mechanism as claimed in any of claims 2 to 4, in which the actuator includes a sleeve portion for connection to transmission means, the sleeve portion being co-axial with and radially outward of the guard member.

6. A mechanism as claimed in any of claims 2 to 5, in which the actuator includes a hand-operable portion.

7. A mechanism as claimed in any preceding claim, including a support relative to which the actuator. is movable and in which the guard member is disposed.

8. In combination, an operating mechanism as claimed in any preceding claim and a key for engagement with the operating mechanism.

9. A combination as claimed in claim 8, in which the key comprises an engagement member for engagement with the actuator means and a handle, the engagement member and handle being jointed to allow relative movement.

10. A combination as claimed in claim 9, in which the handle includes an elongate cylindrical portion to which the engagement member is hingably connected.

11. A lock including an operating mechanism according to any of claims 1 to 7.

12. An operating mechanism substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.

13. A lock substantially as described with reference to, and as shown in, the accompanying drawings.