A lock

Abstract

 A lock comprising: a lock bolt, a handle, a bolt actuator (3) which effects movement of the lock bolt, an actuator operating member (8) and a lock control system (9-19) the actuator operating member (8) operating the bolt actuator (3) upon movement of the handle and under the control of the lock control system (9-19), the lock control system (9-19) including a solenoid (15) and a solenoid energization circuit (17-19), the solenoid energization circuit (17-19) including a switch circuit (18) which operates to energize the solenoid (13) upon verification of an input code with a present code, characterised by the lock control system (9-19) having a control member (11) which is held against movement by the solenoid (15) when energised, whereby the control member (11) permits the actuator operating member (8) to operate the bolt actuator (3) to move the lock bolt with the control member (11) disabling the actuator operating member (8) when the solenoid (15) is not energised.

Description

[0001] This invention relates to a lock. More particularly, the invention relates to a lock which uses a solenoid in controlling operation of the lock.

[0002] Generally when a conventional lock which uses a solenoid-actuated plunger is locked, rotation of a rotary element for actuating a dead bolt, latch bolt or similar key bolt by a handle is restrained by causing a spring force to act in a restraining direction on the plunger or to act on a restraint element such as a stopper lever connected to the plunger. The restraint imposed by the restraint element is removed and rotation of the rotary element, and hence shifting of the dead bolt or similar to an unlocking position, is permitted only when the solenoid is energized as the result of verification of a code for example recorded on a magnetic card, with a preset code.

[0003] In a conventional lock as described above, since the arrangement is one in which restraint on the rotary element is removed by moving the plunger counter to the spring force by energizing the solenoid, the attraction force acting on the plunger must be considerably greater than the spring force. Thus a correspondingly strong magnetic field is required, so necessitating a large solenoid energization current. This results in reduced battery life and shorter replacement intervals and also results in the problem that the plunger action is liable to be uncertain.

[0004] In view of the above, the present invention seeks to provide a lock in which the solenoid energization current at the time of unlocking is relatively small and whose operation is dependable.

[0005] According to the present invention there is provided a lock comprising: a lock bolt, a handle, a bolt actuator which effects movement of the lock bolt, an actuator operating member and a lock control system, the actuator operating member operating the bolt actuator upon movement of the handle and under control of the lock control system, the lock control system including a solenoid and a solenoid energization circuit, the solenoid energization circuit including a switch circuit which operates to energize the solenoid upon verification of an input code with a present code, characterised by the lock control system having a control member which is held against movement by the solenoid when energised, whereby the control member permits the actuator operating member to operate the bolt actuator to move the lock bolt with the control member disabling the actuator operating member when the solenoid is not energized.

[0006] An embodiment of the present invention will now be described by way of example only and with reference to the accompanying drawings, in which:

Figure 1 is a plane view showing, partially as a block diagram, one embodiment of the invention, and

Figure 2 is a side view of the embodiment shown in Figure 1.

[0007] In the drawings, reference numeral 1 indicates the frame of the lock. In the frame 1, there is a lever 2 which is operable by an external handle (not shown) and is so mounted that it can turn about the axis of a shaft 2'. Within frame 1 is also located a bolt actuation member 3 which is so mounted that it can rotate about a shaft 3'. This shaft 3' is connected to a shaft of an ordinary latch lock or the like (not shown). The arrangement is such that when member 3 is rotated in the direction of the arrow A at latch bolt (not shown) is withdrawn from a lock position. Between the frame 1 and the lever 2 and between the frame 1 and member 3 (see Figure 2), there is a carrier element 4 with an elongated opening 4'. Carrier element 4 has side portions guided and supported by a pair of guide elements 6 fixed to the frame 1. The carrier element 4 is disposed so that it can move reciprocally in the directions indicated by the arrows B shown in Figure 1. At the upper end of the carrier element 4 there is a seat element 5 which is formed integrally with the carrier element 4. The seat element 5 is acted upon by lever 2 and is also acted upon by a compression spring 7. The lever 2 and spring 7 act in opposite directions and, in operation, serve to reciprocate the carrier element 4. The compression spring 7 is disposed between an end plate It of the frame 1 and the seat element 5 and acts to urge the carrier element 4 away from the end plate T`.

[0008] On the carrier element 4, there is an actuator operating member 8 which causes rotation of the bolt actuation member 3 by acting upon the edge thereof. The actuator operating member 8 is pivotally mounted at one end on a pin 9 which is fixed to the carrier element 4, parallel with the lower end thereof. The free end of member 8 is urged away from the carrier element 4 by a compression spring 10.

[0009] In the frame 1, there is also provided a control lever 11 which is mounted so that it can pivot about a shaft 12 located part way along its length. The lever 11 contacts the member 8 at a point along the length thereof so as to counter-act the force of the compression spring 10. The member 8 is forced by the control lever 11 to adopt a position (the position indicated by the full line portion of Figure 2) in which the separation of its free end from the carrier element 4 is less than that of the closest surface of the member 3. A plunger 14 fitted with a compression spring 13 is pivotally connected to the end of the control lever 11 opposite to the end wich contacts member 8. The other end of plunger 14 is located in a solenoid 15 fixed to the frame 1. The compression spring 13 acts to cause the plunger 14 to extend out of the solenoid 15 and therefore to urge the control lever 11 against a stop pin 16 which is fixed to the carrier element 4. This exerts a force on the carrier element 4 which is opposed to that of the compression spring 7. Of the two compression springs 7 and 13, spring 7 possesses the greater spring force and thus the carrier element 4 and plunger 14 are balanced in a state in which the free end of the plunger 14 is in contact with the bottom face of the solenoid 15, as shown in Figure 1.

[0010] The solenoid 15 has an energization circuit comprising a switch circuit 18 which is actuated by a CPU 17 which produces a switch-on signal only when a code recorded on a magnetic card or the like, which is inserted into the lock, has been read and verified with a specified code. The energization circuit also includes a microswitch 19 which is closed only when a handle (not shown) for actuating the lever 2 has been turned through a set angle from a neutral position. The switch circuit 18 and microswitch 19 are connected in series. When the switch circuit 18 and miroswitch 19 are both closed, power is supplied to the solenoid 15 and the solenoid attracts the plunger 14 and prevents it from moving, that is, acts to maintain the plunger 14 in the position it is in prior to energization of the solenoid 15.

[0011] In the embodiment thus described, when the handle (not shown) is turned, the lever 2 rotates and the carrier element 4 is moved towards the end plate 1', and so counters the force of the compression spring 7. This movement causes member 8 to be displaced, together with the carrier element 4, and member 8 approaches member 3. However, if power is not supplied to the solenoid 15, the compression spring 13 pushes the plunger 14 downwards and therefore the other end of the control lever 11 continues to remain in contact with stop pin 16. This has the result that the separation of the free end of the member 8 from the carrier element 4 remains substantially constant (the position indicated by the full line portion of Figure 2). Therefore the free end of member 8 moves between member 3 and carrier element 4. The member 3 is therefore not rotated and the latch bolt (not shown) remains in a lock position. In other words, the handle turns to no effect.

[0012] If the handle is turned beyond a set angle causing the microswitch 19 to close and the code of a magnetic card has been verified by the CPU 17 so that switch circuit 18 is switched on, power is supplied to the solenoid 15. As a result, even though the carrier element 4 is displaced towards the end plate 1¹ of the frame 1, the plunger 14 is held in position by the solenoid 15. The upward displacement of the carrier element 4 therefore causes the separation between the free end of the member 8 and the carrier element 4 to increase under the action of the compression spring 10. The free end of member 8 thus moves to a position (indicated by the dashed line portion of Figure 2) in which it lies in more or less the same plane as member 3. When it has come into contact with the edge of member 3, continued movement of the carrier element 4 results in member 8 rotating member 3 in the direction of the arrow A in Figure 1.

[0013] This causes the latch bolt (not shown) that is connected to the shaft 3¹ to be withdrawn, thereby unlocking the door. The microswitch 19 is returned to an open position by a spring force when the handle is released following unlocking, this stops unnecessary supply of power to the solenoid 15 and so prevents wasteful consumption of the battery power.

[0014] Although the above description refers to a latch bolt being actuated by the member 3, other forms of bolts such as a dead bolt are readily envisaged.

[0015] Since, as described in detail above, supply of power to a solenoid for actuation of a plunger results in the plunger being held in the same position in which it was before the supply of power, operation can be effected reliably with a small current and for a battery of given capacity the life is much longer than in a conventional electric lock.

Claims

1. A lock comprising: a lock bolt, a handle, a bolt actuator (3) which effects movement of the lock bolt, an actuator operating member (8) and a lock control system (9-19), the actuator operating member (8) operating the bolt actuator (3) upon movement of the handle and under the control of the lock control system (9-19). the lock control system (9-19) including a solenoid (15) and a solenoid energization circuit (17-19), the solenoid energization circuit (17-19) including a switch circuit (18) which operates to energize the solenoid (15) upon verification of an input code with a present code, characterised by the lock control system (9-19) having a control member (11) which is held against movement by the solenoid (15) when energised, whereby the control member (11) permits the actuator operating member (8) to operate the bolt actuator (3) to move the lock bolt with the control member (8) disabling the actuator operating member (8) when the solenoid (15) is not energised.

2. A lock as claimed in claim 1, characterised in that said energization circuit (17-19) includes a switch (19) in series with said switch circuit (18). said switch (19) being closed when the handle has been moved through a preset distance and being opened when said handle returns to its rest position.

3. A lock as claimed in claim 1 or 2, characterised in that a first spring (13) acts between the solenoid (15) and the control member (11) and a second spring (7) of greater power than the first spring (13) acts against operation of the bolt actuation member (3) by the actuator operating member (8).

4. A lock as claimed in any preceding claim, characterised in that the actuator operating member (8) is located on a carrier (4) which is reciprocated upon movement of the handle.

5. A lock as claimed in claim 4, characterised in that the actuator operating member (8) is a lever pivoted at one end to the carrier (4) and having the other end thereof urged away from the carrier (4) by a spring (10) to a position enabling operation of the bolt actuator (3).

₆. A lock as claimed in claim 5, characterised in that prior to movement of the carrier (4) by the handle the control member (11) holds the actuator operating member (8) against said spring (10) in a position which if maintained upon movement of the carriage (4) does not enable the actuator operating member (8) to operate the bolt actuator (3).

Drawing