GB2206638A - Electromechanical lock - Google Patents

Abstract

The lock includes a bolt (1), bolt-actuating means (2, 3) for withdrawing the bolt when in an enabled state, an electromagnetic device (5) for placing the bolt-actuating means in the enabled state, which is conveniently achieved by rocking an armature (4) out of the path of the bolt-actuating means, and a handle (10) for operating the bolt-actuating means. A detector (11) detects movement of the handle (10) and causes energisation of the electromagnetic device (5) so as to place the bolt-actuating means (2, 3) in the enabled state, allowing the handle (10) to engage therewith to withdraw the bolt (1) hence unlocking the lock. Energisation of the electromagnetic device may be made conditional on entering a valid code by means of a keypad. The lock may be advantageously applied to doors of hotel rooms, ships' cabins and sleeping berths. <IMAGE>

Description

ELECTROMECHANICAL LOCK The present invention relates to an electromechanical lock, for example a door lock for use in doors of hotel rooms, ships' cabins, sleeping berths and the like.

According to a first aspect of the present invention, there is provided a lock, comprising: a bolt; a bolt-actuating means, operable in an enabled state to withdraw the bolt; operating means, engageable with the boltactuating means; an armature, movable between a first position, in which it obstructs the bolt-actuating means, and a second position, which places the bolt-actuating means into the enabled state; and an electromagnetic device which when actuated moves the armature from its first position to its second position; whereby, when the operating means are operated and the electromagnetic device is actuated the boltactuating means engages with the operating means so that operation of the operating means withdraws the bolt into the lock.

In this construction, the electromagnetic device (e.g. a solenoid) has a minimal mechanical load placed upon it during operation.

Conveniently, the operating means is a handle which is operated by turning. It might, however, be a key-operated lever or the like.

Preferably, detecting means are also provided which are operable to detect movement of the handle and to cause actuation of the electromagnetic device in response thereto.

According to a second aspect of the present invention, there is provided a lock comprising: a bolt; bolt-actuating means, operable in an enabled state to withdraw the bolt; an electromagnetic device which when actuated places the bolt-actuating means in the enabled state; a handle operable to engage with the boltactuating means when the latter is in the enabled state; and detecting means operable to detect movement of the handle and to cause actuation of the electromagnetic device in response thereto; whereby when the handle is turned, the detecting means causes the electromagnetic device to actuate placing the bolt-actuating means in the enabled state so that the handle engages with the boltactuating means to withdraw the bolt.

In this construction, the electromagnetic device (e.g. an electromagnet) is actuated only when actually required, thus conserving electrical power.

By contrast, in previous electromechanical locks an electromagnet or solenoid has been actuated over the whole of a time period during which the lock is operable.

Conveniently, the bolt-actuating means is enabled and disabled by an armature, movable between a first position in which it obstructs the bolt-actuating means and a second position which places the bolt actuating means into the enabled state.

Preferably, the detecting means works in conjunction with input means and code checking means for inputting and validating a code required to operate the lock. This provides an electronic lock in which a conventional key is replaced by a numerical or other code. For example, a keypad may be associated with the lock, via which a numerical code is entered which is checked by an electronic circuit (e.g. a microcomputer) to see whether it matches a stored code for the lock.

If the input code matches the stored code, the detecting means is then rendered able to cause actuation of the electromagnetic device within a predetermined time period (e.g a few seconds). Then, turning of the handle within the predetermined time period actuates the electromagnetic device and causes the lock to open.

The electronic circuitry may be reprogrammable, that is, it can be made possible to change the stored code whenever desired to prevent former users of the lock from being able to open the lock in future.

Preferably, the handle is a free handle, that is one which can always be turned but without necessarily being effective to open the lock. This is achieved by arranging the bolt-actuating mechanism so that when in the disabled (obstructed) state, it is freed from all engagement with the handle so that although nothing prevents turning of the handle, turning the handle has no effect. Since the handle is free to turn the lock cannot be "forced" by application of a crowbar or the like to the handle.

As a further security measure, a deadlock ram may be fitted in addition to the main bolt . When the door is closed, the deadlock ram is pressed against a striker plate, and the resulting depression of the deadlock ram actuates a deadlock lever which engages with the bolt-actuating means to prevent the latter from moving. This allows the main bolt to be of the deadlocking type allowing the door to be slammed shut, whilst preventing the main bolt from being forced back into the housing by means of a credit card or the like slipped into the aperture between the door frame and lock.

As a further way of conserving electrical power, the power supply to the electromagnetic device can be pulsed during the relatively short time period when it is actuated. A comparatively long initial pulse of electric current, followed by a series of short pulses, is sufficient to actuate the device and move the armature in the desired manner.

A mechanical override facility can be provided by incorporating into the lock a device which allows an appropriate mechanical key to be inserted and turned, thereby directly or indirectly enabling the outside handle to withdraw the bolt.

When the lock is fitted in a door, usually an additional inside handle will be provided which is always operable to withdraw the bolt simply by turning.

In this way it is always possible to open the lock from the other side of the door (e.g. from the interior of a railway carriage sleeping berth or hotel room).

A lock embodying both aspects of the present invention will now be explained with reference to the accompanying drawings, in which: Figure 1 is an outside front view of the lock casing; Figure 2 is a top view of the lock; Figure 3 is an underneath view; and Figures 4(a) and (b) are a top view and an outside front view, respectively, of the internal mechanism of the lock.

As shown in Figure 1, the external appearance of the lock as seen from the "outside" (e.g. outside of a room) presents a casing 8 with a bolt 1 and a ram 6 protruding from one edge panel On the front panel of the casing, an outside handle 10 is provided for operating the lock and a keyhole 83 is provided for operating a mechanical override device described later.

A keypad, containing buttons 81 and an indicator 82, is also located on the front panel.

Figures 2 to 4 illustrate the internal mechanism of the lock. The principal components include an operating lever 2 for the bolt 1, a handle follower 3 for the outside handle 10, an armature 4, an electromagnetic device 5 (e.g. an electromagnet or solenoid), a deadlock lever 7 for the ram 6, and a mechanical override device 9. These components are mainly located within a frame 80 disposed inside the casing 8. As shown in Figure 2 for example, the other side ("inside") of the lock has a handle 110 and associated handle follower 103.

Referring to Figure 4, the bolt 1 extends along almost the whole length of the lock. It includes a cutout portion 14 for engaging with the inside handle follower as described later. A slot 15 is provided which allows the bolt to slide past a mounting 71 of the deadlock lever to the lock frame. The rear end of the bolt abuts against a spring 19 which is compressed between the bolt and a rear wall of the casing.

The operating lever 2 (shaded in Figure 4) has a generally "L" shape with an upright arm 22. It is mounted to the rear of the bolt at a pivot 21, and includes a notch 23 in its lower edge for engagement with the handle follower 3 of the outside handle. A further notch 24 in its upper edge is provided for receiving a peg 72 of the deadlock lever 7. A spring 25 extends from the arm 22 to a point on the bolt 1, and tends to rotate the lever 2 anticlockwise with a slight spring extension force.

The handle follower 3 is fixed to the outside handle 10, and pivots around a shaft 31, and a similar shaft is provided for the handle follower 103 and inside handle 110. A spring 32 is stretched between the handle follower and a fixed point on the frame 80, and gives the handle 10 a spring return action. A pin 33 protrudes through a slot in the frame 80 for engaging the lock levers. The construction of the inside handle 110, handle follower 103, spring 132 and pin 133 is similar.

Referring to Figures 2 and 4, the armature 4 is pivoted at a point 41 near the upper edge of the frame 80 approximately at its centre of gravity. Near one end a pin 42 is provided, which can obstruct the path of arm 22 of the operating lever 2 as described below. The electromagnet 5 is located beneath the other end 43 of the armature. A small magnetic force from the electromagnet is sufficient to tilt the armature 4 from its normal, approximately horizontal position to a position in which end 43 contacts the electromagnet, which lifts the pin 42 upwards slightly.

When the electromagnet is de-energised, the armature tilts back into the normal position, preferably assisted by a light spring mounted on the electromagnet.

Pin 42, and a pivot pin at point 41, are preferably non-magnetic so as to prevent an unwanted magnetic circuit from being formed around the frame and casing when the electromagnetic is energised.

The electromagnet 5 may alternatively be a solenoid or other electromagnetic device.

The ram 6 and deadlock lever 7 give the lock a deadlocking action. A first spring pin 61, fixed at one end to the ram, determines how far the ram normally protrudes from the lock casing. An upright arm 73 of the deadlock lever 7 abuts against the other end of spring pin 61, and a second spring pin 62 abuts against this arm 73 at one end and reacts against an abutment 90 attached to the casing at its other end, thereby tending to push the ram outwards when the deadlock lever is free to move. The deadlock lever 7 is pivoted at a fixed point 71 on the casing, and has a protrusion or peg 72 on an upper side for engaging with the notch 24 in the operating lever 2. In addition, deadlock lever 7 has a concave lower edge 74 which is engageable by the pin 133 of inside handle follower 103 (please refer to Figure 3).

A pin 76 (see Figure 4(b)) limits the clockwise rotation of deadlock lever 7 to enable slot 24 of lever 2 to disengage from peg 72,thus releasing the deadlock feature and allowing bolt 1 to be withdrawn by the action of lever 2.

The mechanical override device 9 provides a mechanical key-actuated override bolt 91 (shown extended in Figure 4(b)). This override bolt, when extended, forces the armature 4 into the position in which the pin 42 clears the arm 22 of the operating lever 2.

Other parts of the lock include a first microswitch 11, arranged in the path of the outside handle follower 3 for detecting movement of the outside handle; a second microswitch 12 located near the rear end of the path of the bolt, for detecting when the bolt has been withdrawn; and a microcomputer 18 linked to the keypad, microswitches and electromagnet for control of the lock.

The operation for opening the lock from the outside is as follows. Referring to Figure 1, the user enters a numerical code, for example a four-digit code, using the buttons 81. The code is received by the microcomputer which compares the entered code with a stored code for the lock. If the two codes match, the microcomputer 18 authorises opening of the lock. That is to say, it adopts a condition in which any switching of the first microswitch 11 taking place within a following predetermined time period (e.g. four seconds) will result in the electromagnet 5 being energised.

The microcomputer lights the indicator 82 to show this condition.

If the user starts to turn the outside handle 10 clockwise within the predetermined period ("lockenabled" period) the microswitch 11 is triggered, passing a signal to the microcomputer 18 which energises the electromagnet 5 for a time sufficient to tilt the armature 4 over to its position in which pin 42 clears the operating lever 2. The energisation of the electromagnet may consist, for example, of a relatively long pulse of electric current followed by a series of spaced-apart short pulses, the whole energisation period occupying only a fraction of a second. Such a short energisation period is practical because, by use of the microswitch 11, the magnet is energised only when it is actually required as opposed to over the whole lock-enabled period.

Referring to Figure 4(b), as the handle 10 is turned further, the operating lever 2 rotates anticlockwise slightly under the action of spring 25 with the result that pin 33 of handle follower 3 engages the lower edge of the operating lever and starts to enter the notch 23. With further clockwise turning of the handle, the notch 23 descends so that pin 33 moves right into the notch, becoming trapped in the hookshaped right hand portion (as seen in the Figure ) of that notch 23. The operating lever 2 is by this time free of engagement with the peg 72 of deadlock lever 7.

Further turning of the outside handle then forces the operating lever to move back (to the right in Figure 4), pushing the bolt 1 back with it, until the bolt is fully withdrawn into the casing. (Soon after lever 2 begins its rightward travel, the armature 4, which is no longer attracted to the de-energised electromagnet, returns to its rest position.) The door or the like secured by the lock can then be opened.

Once the outside handle is released, the bolt 1 returns under the action of compressed spring 19, and the handle is returned to a horizontal position by spring 32 (Figure 3) assisted by spring 19.

Attempts to open the lock improperly have the following effects.

Supposing that the lock is mounted in a door which is currently in a closed state, then the bolt 1 and ram 6 engage a striker plate of the door frame.

That is, the bolt 1 is in its outward extended position, engaged in an aperture in the striker plate, and the ram 6 is pressed against the face of the striker plate and hence is somewhat depressed into the lock casing.

If an attempt is made to force the outside handle 10, the handle turns in the normal way but there is no effect on the lock mechanism. This is because the pin 42 of armature 4 prevents the lever 2 from descending into engagement with the pin 33 of the handle follower 3. In fact, the outside handle 10 and follower 3 are free of any engagement with the internal mechanism of the lock.

Similarly, if an incorrect code is entered via the keypad and the handle is turned, there is also no effect because the armature 4 is still in the position obstructing the lever 2.

If an attempt is made to force the bolt 1 back into the casing, by means of a credit card or the like slipped between the door and the door frame, the deadlock provided by ram 6 and deadlock lever 7 comes into play. That is, in the closed-door condition described above, the peg 72 of deadlock lever 7 engages with notch 24 (see Figure 4(b)). Since the lever 7 is pivoted on the lock frame, peg 72 and hence the bolt 1 is fixed with regard to horizontal movement so the bolt cannot be forced back. On the other hand, as soon as the door is opened, the ram 6 springs out under the action of spring pin 62 and this rotates deadlock lever 7 anticlockwise into the position shown in Figure 4(b), with the peg 72 clear of the operating lever 2.

The lock can however be opened independently of the keypad, by use of the mechanical override device. Turning of an appropriate mechanical key in the keyhole actuates the bolt 91, which pushes upwards against the armature 4 and clears the pin 42 away from the path of operating lever 2. Hence the action of the electromagnet is mechanically overridden. The override device 9 allows the lock to be opened purely mechanically in case of emergency or if the user has forgotten the lock code, for example by the attendant when the lock is used for a sleeping berth.

The lock can also be opened at any time from the inside (e.g. the inside of a sleeping berth or hotel room), simply by turning the inside handle 110.

As indicated in Figure 3, turning of handle 110 causes handle follower 103 to rotate, leading pin 133 to push upwards against deadlock lever 7, clearing it from any engagement with operating lever 2, and to push rightwards against the wall of cutout portion 14 of the bolt 1, forcing it back into the lock.

A major advantage of an electronic lock in comparison with a mechanical lock is that, in general, reprogramming of the code for opening the lock is possible. This has obvious security benefits for hotel rooms, sleeping berths and the like such as allowing many different users access over a long period of time, without former users being able to open the lock after their period of occupancy of the sleeping berth, hotel room or the like has expired.

In this embodiment of the present invention, reprogrammability can be provided as follows. After the present lock code has been entered and lock opening authorised by the microcomputer, the user turns the handle to withdraw the bolt in the normal way. When the bolt reaches the rearmost end of its travel, this triggers the second microswitch 12, which sends a signal to the microcomputer. The microcomputer then adopts a condition in which any new code entered via the keypad, whilst the handle is kept depressed and the bolt held withdrawn, replaces the present code as the stored code for the lock. As will be apparent, this allows reprogramming to be effected very easily without affecting the normal operation of the lock.

Alternatively, or in addition, a microswitch associated with the mechanical override device 9 could be provided and the microcomputer made responsive to a new code only when a mechanical key is inserted into the device 9, and turned.

Some of the attributes and advantages of the above-described lock are as follows.

Firstly, the lock mechanism is enabled and disabled by an electromagnet or other electromagnetic device. Whereas other electromechanical locks exist, an advantage of this lock is that there is minimal load placed on the electromagnet in use. Rather than having to actuate one of the lock levers, the electromagnet simply tilts a free-mounted armature through a small angle. This allows the electromagnet to be relatively small and low-powered in comparison with those in previous electromechanical locks.

Secondly, the electromagnet is only eneregised at the exact time when it is required, i.e. when the handle starts to turn. In previous electromechanical locks, an electromagnetic device is actuated during the whole of a "lock-enabled" period, e.g. several seconds.

By virtue of sensing the rotation of the outside handle by the microswitch 11, the energisation time of the electromagnet in the present lock is reduced to the fraction of a second needed to tilt the armature in the above-described manner.

As will be apparent, the above two features of the lock together greatly reduce the power consumption required for operation of the lock. This makes it practical to power the lock using small dry batteries rather than a mains supply, and a set of batteries may last for several years in normal use. A compact and self-contained lock requiring practically no maintenance is thus provided.

The lock can be particularly advantageously applied to the doors of hotel rooms, ships cabins and sleeping berths. Conventional mechanical locks employed in such doors can usually only be opened by an attendant, causing considerable inconvenience and hindering free movement of people into and out of the accommodation. If the above-mentioned lock is employed, however, people may be allowed to open the locks themselves (the lock codes being changed at the end of the usage), thus giving people free access to accommodation without having to trouble the attendant.

Claims (13)

CLAIMS:

1. A lock, comprising: a bolt; bolt-actuating means, operable in an enabled state to withdraw the bolt; operating means, engageable with the boltactuating means; an armature, movable between a first position, in which it obstructs the bolt-actuating means, and a second position, which places the bolt-actuating means into the enabled state; and an electromagnetic device which when actuated moves the armature from its first position to its second position; whereby, when the operating means are operated and the electromagnetic device is actuated, the boltactuating means engages with the operating means so that operation of the operating means withdraws the bolt into the lock.

2. A lock as claimed in claim 1, wherein the operating means is a handle, and wherein the lock further comprises detecting means operable to detect movement of the handle and to cause actuation of the electromagnetic device in response thereto.

3. A lock, comprising: a bolt; bolt-actuating means, operable in an enabled state to withdraw the bolt; an electromagnetic device which when actuated places the bolt-actuating means in the enabled state; a handle operable to engage with the boltactuating means when the latter is in the. enabled state; and detecting means operable to detect movement of the handle and to cause actuation of the electromagnetic device in response thereto; whereby when the handle is turned, the detecting means causes the electromagnetic device to actuate, placing the bolt-actuating means in the enabled state so that the handle engages with the boltactuating means to withdraw the bolt.

4. A lock as claimed in claim 3, wherein the bolt-actuating means is enabled and disabled by an armature, movable between a first position in which it obstructs the bolt-actuating means and a second position which places the bolt actuating means into the enabled state.

5. A lock as claimed in claim 2, 3 or 4, further comprising input means and code-checking means for inputting and validating a code required to operate the lock and operable to enable operation of the detecting means in response to a valid code.

6. A lock as claimed in claim 5, wherein the code checking means comprises a reprogrammable memory for storing the valid code.

7. A lock as claimed in any one of claims 2 to 6, wherein the bolt-actuating means is arranged seach that when in the disabled state, it is freed from all engagement with the handle so that turning of the handle has no effect.

8. A lock as claimed in any preceding claim, being a door lock and further comprising a deadlock ram and deadlock lever operable, in co-operation with a striker plate mounted in the door frame, to engage with the bolt-actuating means to prevent movement thereof whilst the door is closed.

9. A lock as claimed in any preceding claim, wherein the electromagnetic device is arranged to receive a pulsed power supply.

10. A lock as claimed in claim 9, wherein the pulsed power supply provides a relatively long initial pulse of electric current followed by a series of relatively short pulses of electric current.

11. A lock as claimed in any preceding claim, further comprising a mechanical override device for receiving a mechanical key and operable by the key to enable the operating means or handle to withdraw the bolt under all circumstances.

12. A lock as claimed in any preceding claim, further comprising additional operating menus provided at an opposite side of the lock from the said operating means or handle and operable to withdraw the bolt under all circumstances.

13. A lock, substantially as hereinbefore described with reference to the accompanying drawings.