GB2255368A - Electro-mechanical lock devices - Google Patents

Abstract

A lock device comprises a housing 10 in which a rotor 11 is mounted. An electrically operable locking arrangement including a locking pawl 21a is employed to restrain turning of the rotor 11 relative to the housing 10 unless an electromagnet 26 is energised to release such locking arrangement. When the rotor is turned by means of handle 13, lock cylinder 17 turns with it and rotates pan of the fastening operating linkage. To enable operation of the fastening independently of the electrical mechanism when the latter is locked, the lock cylinder 17 can be unlocked by means of a key, whereupon it can rotate within the rotor 11 and operate the fastening. <IMAGE>

Description

ELECTRO-MECHANICAL LOCK DEVICES This invention relates to electro-mechanical lock devices for doors and other closures.

Traditional door locks make use of key operated release mechanisms such as the conventional pin-tumbler type cylinder mechanism. In recent years, however, more consideration has been given to lock devices which can be actuated electronically by a push-button keyboard or an optical or magnetic reading device.

When a locking device is solely electrically actuable and self-contained, it must contain an internal battery of some sort to provide power to the electronic circuits and to an electro-mechanical output device which controls displacement of a mechanical element of the lock device to determine whether or not the fastening controlled by the lock can be operated. Battery failure may leave the lock in a condition in which the services of a locksmith are required to re-open the fastening before the battery can be replaced and this is clearly undesirable for an ordinary domestic lock where regular maintenance is not to be expected. Although, by the use of present day technology, it is possible to prolong the battery very considerably, the battery will eventually have to be replaced.

One object of the present invention is to provide a combined mechanical and electronic lock device which can be operated either by means of a key or electronically.

A lock device in accordance with the invention comprises a lock housing, a rotor mounted in said housing for angular movement relative thereto, detent means for preventing rotation of the rotor in the housing, electrically actuable release means for de-activating said detent means, a key-operable locking cylinder mounted in the rotor and output means for transmitting rotary movement of said locking cylinder to a fastening.

With such an arrangement, the lock device can normally be actuated, without using any mechanical key, simply by actuating said release means. When the electrically actuable release means is inoperative for any reason, however, the lock device can still be actuated by inserting a matching key into the keyoperable locking cylinder. The locking cylinder serves to transmit rotary movement from the rotor to the output means when no matching key is inserted.

A suitable low energy release means is disclosed in European Patent Application No. 89312188.9 (publication no. 371701), which describes a lock device in which, in the normal locked position of a rotor of the lock, a cam surface on the rotor maintains a spring loaded latch element in a position such that the air gap between a release solenoid and an armature therefor is at a minimum. Initial turning of the rotor out of its locked position allows the latch element to move to a detent position to prevent further rotation unless the solenoid is energised. The energy required to hold the latch element in its initial position is considerably less than that which would be required to pull the armature in.

The spring-loaded latch element of the lock device of this prior proposal, has a spring which biases it relative to the lock housing and it has been found that such an arrangement may not necessarily be proof against a method of unauthorised lock release known as "rapping".

This method involves applying a turning force to the rotor of the lock whilst tapping it with a suitable instrument. The shocks created by the tapping can cause a detent element to jump sufficiently to enable the rotor to be turned beyond the position at which the detect effect is active.

It is an object of the invention to provide an electro-magnetically releasable lock device in which this possible deficiency is overcome.

In accordance with another aspect of the invention, therefore, there is provided a lock device comprising a housing, a rotor mounted in the housing, a latch element pivotally mounted in the housing and coacting with a cam surface on said rotor, an electromagnet in said housing co-acting with an armature on said latch element so as to prevent the latch element being displaced to a detent position on initial turning of said rotor out of a rest position when the electromagnet is energised, and a cam following element arranged to follow a further cam surface on the rotor and coupled to the latch element so as to turn therewith when the electromagnet is not energised, said further cam surface being arranged so that the latch element is urged towards its detent position by displacement of the cam following element on said initial turning of the rotor.

The latch element and the cam follower element may be spring loaded relative to one another so that stop portions thereon are interengaged. When the electromagnet is not energised these two parts move as one in the manner of a bell crank lever. When the electromagnet is energised, however, so that movement of the latch element is prevented, the cam follower can move independently of the latch element.

In order to ensure that the electromagnet armature approaches the electromagnet as closely as possible when the rotor is in its rest position, the electromagnet may be mounted so as to be movable slightly relative to the housing towards and away from the armature. This feature allows the air gap to be minimised without imposing exacting tolerances on the manufacture of the device.

In the accompanying drawings: Figure 1 is a front elevation of one example of a lock device in accordance with the invention; Figure 2 is a rear elevation of the device of Figure 1 shown with its rear cover removed; and Figure 3 is an exploded sectional view of the device.

The lock device has a housing 10 in which there is a rotor 11 rotatably mounted. The rotor comprises a body 12, a knob/handle 13 attached to one end of the body, a first and second cam parts 14 and 15 both attached to the opposite end of the body. The rotor is spring-loaded relative to the housing 10 by a torsion spring 16 surrounding the body of the rotor, so that the latter is urged in a clockwise direction as viewed in Figure 2 to a rest position defined by interengaged stop portions (not shown) on the rotor body and the housing.

The body 12 of the rotor has an axial bore containing a rotatable plug 17, and a conventional pintumbler locking arrangement is provided to lock the plug 17 against rotation relative to the rotor, except when an appropriate key is inserted into a key slot 17 in the plug.

An output means for the locking device is provided by a metal strip 20 which is fitted into a slot in the plug 17 so that it can transmit rotary movement and torque to a co-acting latching mechanism.

A latching element 21 and a cam following element 22 are mounted on the housing 10 for angular movement about a common axis parallel to and spaced from the common rotary axis of the rotor 12 and the plug 17. The latching element 21 has a detent portion 21- which coacts with a cam surface on the first cam part 14. As shown in Figure 2, the detent portion 21a is resting on the cam surface of part 14 in a position which permits initial turning of the later in an anti-clockwise direction, but a recess 14a in the cam 14 is positioned so that during such initial turning movement the latch element 21 can drop into a detent position in which the detent portion 21a fits into the recess 14a to prevent further anticlockwise turning of the rotor.This limited permitted angular motion of the rotor 11 is sufficient only to take up lost motion in the latch mechanism with which the locking device co-acts and does not cause release of the latch mechanism.

The cam following element 22 is coupled to the latch element 21 by a spring/stop arrangement 23, 24 so that the two elements can normally move as one, unless the latch element is restrained from moving. The cam following element 22 co-acts with the second cam part 15 which is shaped to displace the cam element in a clockwise direction, causing movement of the latch element to its detent position during the initial anticlockwise turning of the rotor 11 referred to above.

The arrangement described thus far is such that the rotor 11 can only be turned if some external force is applied to the latch element 21 to prevent it being displaced into its detent position by the cam following element 22 during initial turning of the rotor out of its rest position. The arrangement for restraining the latch element 21 when required is described hereafter. The latch element 21 and the cam following element 22 move as one in the manner of a bell-crank lever during normal, unrestrained action. If an attempt is made to release the locking device by so-called "rapping", the turning action which must be applied to the rotor in synchronism with the impacts on it will cause the cam following element to turn, thereby applying to the latch element forces which oppose those created by the impacts.

The restraining arrangement for the latch element 21 comprises an electro-magnet 25 which coacts with an armature 26 mounted on the latch element 21. The electromagnet 25 is mounted on a bar 29 and is connected electrically to a circuit board 27 which carries the electronic circuits by means of which the electromagnet winding is supplied with current from a battery 28.

The bar 29 is not secured firmly in position in the housing 10 but is left held captive by two sockets 30 in the housing and is free to move vertically through a short distance. This ensures that when the latch element 21 is in the position shown the electromagnet 25 can rest on the armature 26 and thereby ensure that any air gap in the magnetic circuit of the electromagnet/armature combination is minimised. The current required to hold the armature in position can then be very small indeed and this ensures a long battery life. It will be noted that the portion 14b of cam 14 to the left of recess 14a is of larger diameter than that of portion 14c on the opposite side. This ensures that when the electromagnet drops slightly on initial turning of the handle, the latch element 21 remains clear of the recess 14a When the electromagnet is energised, it restrains turing of the latch element 21 during the initial anti clockwise turning of the rotor 11. The cam following element 22 moves independently of the latch element 21, stressing the spring 23 somewhat, but not causing sufficient additional spring force on the latch element 21 for the latter to be displaced.

It will be noted that the locking device described can be operated using the electronic circuit to energise the electromagnet, permitting turning of the rotor 11 and the plug 17 as one, or by inserting a key into the key slot 17a and turning the plug 17 alone.

Claims (13)

1. A lock device comprising a lock housing, a rotor mounted in said housing for angular movement relative thereto, detent means for preventing rotation of the rotor in the housing, electrically actuable release means for de-activating said detent means, a key-operable locking cylinder mounted in the rotor and output means for transmitting rotary movement of said locking cylinder to a fastening.

2. A lock device as claimed in Claim 1, in which said rotor is spring-loaded relative to the housing to a rest position.

3. A lock device as claimed in Claim 2, in which said detent means comprises a cam on the rotor and a co-acting latching element mounted in the housing.

4. A lock device as claimed in Claim 3, in which said cam and said latching element are so shaped that when the rotor is in its rest position, the latching element occupies a position such that initial turning of the rotor out of its rest position is permitted, such initial turning resulting in displacement of the latching element to a detent position unless said electrically actuable release means is operative to prevent such displacement.

5. A lock device as claimed in Claim 4, in which said electrically actuable release means is in the form of an electromagnet mounted in the housing and co-acting with an armature on the latching element, so as to restrain the latching element whenever the electromagnet is energised.

6. A lock device as claimed in Claim 5, in which said electromagnet is mounted so as to be movable slightly relative to the housing in a direction towards and away from said armature, whereby the air gap between the electromagnet and the armature is automatically minimised in use.

7. A lock device as claimed in any of Claims 4 to 6, in which there is further provided a cam follower element arranged to follow a further cam on the rotor and coupled to the latching element so as to be displaced therewith when the electrically actuable release means is not activated, said further cam being arranged so that the latching element is urged towards its detent position by displacement of the cam following element on initial turning of the rotor.

8. A lock device as claimed in Claim 7, in which the latching element and the cam follower element are pivotally mounted on a common axis and are spring-loaded relative to one another so that stop portions thereon are interengaged when the rotor is in its rest position, whereby the cam follower element is movable independently of the latching element when the electrically actuable release means is activated.

9. A lock device comprising a housing, a rotor mounted in the housing, a latch element pivotally mounted in the housing and co-acting with a cam surface on said rotor, an electromagnet in said housing co-acting with an armature on said latch element so as to prevent the latch element being displaced to a detent position on initial turning of said rotor out of a rest position when the electromagnet is energised, and a cam following element arranged to follow a further cam surface on the rotor and coupled to the latch element so as to turn therewith when the electromagnet is not energised, said further cam surface being arranged so that the latch element is urged towards its detent position by displacement of the cam following element on said initial turning of the rotor.

10. A lock device as claimed in Claim 9, in which said latch element and said cam following element are pivotally mounted for independent pivotal movement relative to the housing about a common axis.

11. A lock device as claimed in Claim 10, in which the latch element and the cam follower element are springloaded relative to one another such that stop portions thereon are interengaged.

12. A lock device as claimed in Claim 9, 10 or 11, in which said electromagnet is mounted in the housing so as to be slightly movable relative thereto towards and away from the armature.

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