GB2307270A

GB2307270A - A lock mechanism

Info

Publication number: GB2307270A
Application number: GB9523627A
Authority: GB
Inventors: Bernard Viney
Original assignee: Surelock McGill Ltd
Current assignee: Surelock McGill Ltd
Priority date: 1995-11-17
Filing date: 1995-11-17
Publication date: 1997-05-21
Anticipated expiration: 2015-11-17
Also published as: ZA969632B; GB2307270B; WO1997019240A1; AU7583096A; GB9523627D0

Abstract

A lock mechanism for a member movable in a frame comprises a bolt and a mechanism 14 to restrain the bolt in a retracted position. A restraint driving means 9 engages with the frame or the movable member when the movable member is closed to release the bolt member restraint. An electrically driven means 33, 34 is engaged to retract the bolt and holds it retracted against the bias of spring means 6. Manual override means 29, 30 is movable in a first direction to retract the bolt and to uncouple the restraint driving means to enable the restraining mechanism to restrain the bolt; and movable in a second direction to drive the restraining mechanism to release the restraint on the bolt and to re-couple the driving means to the restraining mechanism. The manual override means is operable only if the electrically driven means is engaged.

Description

A LOCK MECHANISM The present invention generally relates to a lock mechanism for fixing to a movable member or to a frame for locking the movable member in a close position in the frame, and in particular the present invention relates to a lock mechanism which can be both electrically and manually driven.

There is a need for lock mechanisms for medium or high security applications which can be locked both electrically and manually. Such locks have particular applications in prisons and the like. A particular requirement for such applications is that the lock mechanism is able to be operated electrically to unlock and lock a door whilst still allowing for the manual unlocking of the door in an emergency when there may be power failure to the electrical drive mechanism.

One such lock mechanism which is currently available on the market is the 120M Series supplied by Folder Adam Company,163000W 103rd Street, Lemont, Illinois 60439, United States of America. The 120M Series locks have a latch-bolt member which extends from the latch mechanism which can be mounted on the door or the door frame to contact the other of the door frame of the door. There is also provided a ball catch to detect whether the door is shut. Once the door is unlocked by the energisation of the motor, the latch-bolt is held mechanically retracted. If the motor is energised to extend the latch-bolt, the latch-bolt is still held mechanically retracted until the door is opened whereupon the ball catch detects the opening of the door and the latch-bolt is released. The lock mechanism is also provided with a cylinder key for the manual operation of the latchbolt.Under key operation when the door is shut, the latch-bolt can be retracted and held mechanically retracted. If the key is rotated in the opposite direction to extend the latch-bolt, the latch-bolt is held mechanically retracted until the door is open.

When the door is open, the latch-bolt will automatically extend. When the door is open, the electric motor and the key mechanism can be used to retract and extend the latch-bolt.

This prior art lock mechanism suffers from a serious disadvantage in that when the door is shut and the latch-bolt is retracted either by the electric motor or manually using the key, it cannot be extended again until the door has been opened. The lock mechanism requires the latch-bolt to be in its extended position as the door is shut. The latch-bolt cannot be extended once the door is shut. Thus, if, for instance in a prison environment, the motor was accidentally energised, or in a situation where the latch-bolt was retracted to open the door and it was necessary to quickly re-lock the door, the lock mechanism suffers from the disadvantage that the door must first be opened and closed. Where the lock mechanism is being operated remotely this requires a person to go to the door and carry out the opening and closing operation which is undesirable.In a high security environment where there is an unexpected situation arising for example with the prisoner as the door is being unlocked, it would be highly advantageous to be able to immediately re-lock the door without having to open it first.

The prior art lock mechanism also suffers from the disadvantage that a latch-bolt is used. Such a latch-bolt requires an angled face to enable the latch-bolt to latch into its locked position as the door is shut. This angled face of a latch-bolt provides an inherent weakness in such a lock mechanism. The angled face severely reduces the mechanical strength of the bolting mechanism.

It is therefore an object of the present invention to provide a lock mechanism which can be operated both electrically and manually when affixed to a movable member such as a door or to a frame to allow the extension and retraction of a bolt member when the movable member is in a closed position.

The present invention provides a lock mechanism for fixing to a movable member or frame for locking said movable member in a closed position in said frame, the lock mechanism comprising a bolt member movable between a disengaged position and a engaged position for engagement with said frame or said movable member; a restraining mechanism to engage and restrain said bolt member when said bolt member is in said disengaged position; restraint driving means coupled to said restraining mechanism to engage with said frame or said movable member when said movable member is closed to drive said restraining mechanism to release the restraint on said bolt member; an electrically driven means movable between an engaged state and a disengaged state, said electrically driven means being arranged to be movable from an engaged state to a disengaged state to drive said bolt member into said disengaged position and to hold said bolt member in said disengaged position; bolt urging means to urge said bolt member into said engaged position and to hold said bolt member in said engaged position when said electrically driven means moves to said disengaged state and said restraining mechanism releases the restraint on said bolt member; and manual override means movable in a first direction to drive said bolt member into said disengaged position from said engaged position and to uncouple said restraint driving means from said restraining mechanism to enable said restraining mechanism to restrain said bolt member, and movable in a second direction to drive said restraining mechanism to release the restraint on said bolt member and to re-couple said driving means to said restraining mechanism, said manual override means being arranged to be operative only if said electrically driven means is in an engaged state.

Thus, when the movable member such as a door is in a closed position, the bolt member can be moved between its engaged and disengaged positions either by operation of the electrically driven means or by the operation of the manual override means when the electrically driven means is in the engaged position.

In one embodiment said restraint mechanism comprises a restraint member connected to a bistable member, said bistable member having an electrically driven position in which said bistable member provides coupling between said restraint member and said restraint driving means, and a manually driven position in which said restraint member is decoupled from said restraint driving means.

Preferably said bolt member has a shoulder for engagement with said restraint member, said restrain mechanism including a pivot, said restraint member being pivotably mounted on said pivot and pivotable between a restraining position and a releasing position, said biasing means biasing said restraint member towards said restraining position, said restraint member having a first arm member for engaging with said shoulder of said bolt member and positioned on one side of said pivot, said release member comprising a second arm member on the other side of said pivot to said first arm member.

In one embodiment said bistable member is movable by said manual override means from said electrically driven position to said manually driven position, said restraint mechanism including biasing means to bias said restraint member towards engagement with said bolt member for restraint of said bolt member when said bolt member is in said disengaged position, and a release member for engagement by said manual override means when driven in said second direction to release the restraint on said bolt member, said bistable member being movable by said bolt member from said manually driven position to said electrically driven position as said bolt member moves from said disengaged position to said engaged position.

Conveniently said restraint member has a second pivot mounted thereon, said bistable member being pivotably mounted on said second pivot, said bistable member being rotatable about said second pivot between said electrically driven position and said manually driven position, said bistable member having a first arm member for engagement with said restraint driving means to couple said restraint driving means and said restraining mechanism when said bistable member is in said electrically driven position, a second arm member for engagement by said manual override means to rotate said bistable member to said manual position as said manual override means is moved in said first direction, and a peg member for engagement with said shoulder of said bolt member to move said bistable member from said manually driven position to said electrically driven position as said bolt member moves from said disengaged position to said engaged position.

In an alternative embodiment said bistable member is movable by said manual override means from said electrically driven position to said manually driven position, said restraint mechanism including biasing means to bias said restraint member towards engagement with said bolt member for restraint of said bolt member when said bolt member is in said disengaged position, and a release member for engagement by said manual override means when driven in said second direction to release the restraint on said bolt member, said bistable member being movable from said manually driven position to said electrically driven position when said electrically driven means moves from said engaged state to said disengaged state.

In this alternative embodiment conveniently said restraint member has a second pivot mounted thereon, said bistable member being pivotably mounted on said second pivot and biased towards said electrically driven position, said bistable member being rotatable about said second pivot between said electrically driven position and said manually driven position, said electrically driven means including a bistable latch mechanism for holding said bistable member in said manually driven position when said electrically driven means is in said engaged position, and for releasing said bistable member when said electrically driven means moves to said disengaged position, said bistable member having a first arm member for engagement with said restraint driving means to couple said restraint driving means and said restraining mechanism when said bistable member is in said electrically driven position, a second arm member for engagement by said manual override means to rotate said bistable member to said manual position as said manual override means is moved in said first direction, and a peg member for engagement with said bistable latch mechanism to hold said bistable member in said manually driven position, said bistable member being biased to electrically driven position as said electrically driven means moves from said engaged state to said disengaged state.

In a preferred embodiment the manual override means comprises a cam arrangement which is rotatable by manual force in first and second directions. Said cam arrangement conveniently comprises a first cam having a short cam arm and a second cam having a long cam arm, said first and second cams being rotatable about a common axis, said second cam having an extending portion for engagement by said first cam as said first cam is rotated in said first direction to rotationally pick up said second cam and engage said long cam arm with said shoulder of said bolt member to drive said bolt member to said disengaged position, said short cam arm of said first cam being arranged to engage said second cam member of said restraint member when said first cam is rotated in said second direction to release the restraint on said bolt member.

In one embodiment the first cam has a slot on the axis of the cams to receive a tang of a conventional key cylinder. As the key operates within the key cylinder the tang of the key cylinder rotates to cause the rotation of the cams.

In order to enable the lock mechanism to be manually operated with a large degree of force which is not possible by the simple use of a key, the first cam preferably has a recess for receiving a lever for manual rotation of the first cam for operation of the manual override means in the first and second directions. Further, the second cam can conveniently have a recess for receiving a similar lever for manual rotation of a second cam to operate the manual override means in the first direction. Thus, this facility allows for the manual override means to be operated with a significant amount of force to retract the bolt member. This feature can be a significant advantage where the lock mechanism could be used to lock a door subject to siege conditions where a large amount of force is being applied against the door.In order to retract the bolt and enable the door to be opened, a large amount of force is required to be able to retract the bolt member. This can be applied in accordance with this embodiment of the present invention using a lever applied to one of the cams from either side of the lock mechanism.

A further feature of one embodiment of the present invention is the provision of roll means at the end of the bolt member which engages with the frame or movable member respectively. The roll means which is conveniently a roller is designed to reduce the friction between the bolt member and the recess in the frame or movable member to allow for the easier retraction of the bolt member.

A further preferable security feature of the present invention is the provision of an end force latch connected to the bolt member to engage the electrically driven means when the bolt member is in its engaged position to prevent the bolt member being moved from its engaged position to its disengaged position by the application of force to the protruding end.

A convenient method of detecting whether the door is open or shut and providing a restraint driving means to drive the restraint member, is a drive member which is movable translationally between an engaged position when the drive member is engaged with the frame or the movable member respectively and a disengaged position. The driving member has roll means at an end thereof which is conveniently a roller and which engages with the frame or the movable member respectively and is arranged to have an axis of rotation perpendicular to the direction of motion of the driving member and parallel to a direction of insertion of the movable member into the frame as the movable member is moved to its closed position.

Although the present invention can utilise any electrically driven means such as a solenoid, for medium or high security applications such a device does not generally provide sufficient force to drive the bolt member into engagement. Thus, preferably the electrically driven means includes an electric motor.

The electrically driven means thus conveniently comprises an electric motor coupled to a shaft. The shaft carries a drive arm extending perpendicularly to an axis of the shaft. The drive arm is arranged to engage a drive face of the bolt member to drive the bolt member from the engaged position to the disengaged position as the shaft rotates.

In order to reduce frictional forces, the drive arm preferably has roll means arranged thereon which is arranged to rotate about an axis parallel to the axis of rotation of the shaft. Further, in order to increase the torque provided by the electric motor, preferably a gear box is provided between the electric motor and the shaft to reduce the rotation rate of the shaft relative to the electric motor.

In order to enable the status of various parts of the lock mechanism to be monitored, preferably electric switch arrangements can be provided to monitor the position of any one of the bolt member, the electrically driven means, and the restraint driving means. In this way the status of the lock mechanism can be remotely monitored.

The embodiments of the present invention will now be described with reference to the accompanying drawings, in which: Figure 1 illustrates a plan sectional view through the lock mechanism in accordance with one embodiment of the present invention wherein said lock mechanism is in an electrically locked state with the door closed; Figure 2 illustrates a plan sectional view through the lock mechanism of Figure 1 wherein the lock mechanism is in a manually unlocked position with the door closed; Figure 3 illustrates the embodiment of Figure 1 in an electrically unlocked state with the door closed; Figure 4 illustrates a side view of the embodiment of Figure 1; Figure 5 illustrates an end view of the embodiments of Figures 1, 2 or 3; Figure 6 illustrates the cover plate for the lock mechanism of Figures 1, 2 or 3;; Figures 7a, 7b and 7c illustrate respectively an end view, a plan view, and a side view of the restraint member; Figures 8a, 8b and 8c illustrates respectively an end view, a plan view, and a side view of the bistable member; Figures 9a and 9b illustrate respectively an end view and a plan view of a part of a lock mechanism of an alternative embodiment of the present invention where the bistable member is in a manually driven position; and Figures 10a and 10b illustrate respectively an end view and a plan view of the embodiment of Figures 9a and 9b wherein the bistable member is in an electrically driven position.

Referring now to the drawings, a lock mechanism in accordance with one embodiment of the present invention comprises a lock member 1 retained by guides 2a and 2b within a housing 3 and movable translationally between an engaged state wherein the lock member 1 extends from within the housing 3, to a disengaged position wherein an end lb of the lock member 1 lies substantially flush with a face 3a of the housing 3. At the end of the lock member 1 which extends from the housing 3 there is provided a roller 4 which is free to rotate along an axis parallel to the long axis of the housing 3. Within the lock member 1 there is provided a hardened steel pin 5 as a security measure to prevent the lock member being sawn.

Within the lock member 1 there is provided a compression spring 6 anchored to a pin 7 to urge the lock member 1 towards its engaged position. The pin 7 is arranged to slide within a guide slot 8 provided within the lock member 1.

In a position at the side of the housing 3 in the face 3a adjacent to the lock member 1, there is provided a restraint drive member 9 movable translationally between an engaged position and a disengaged position. When the door is open, the restraint drive mechanism extends outwards from the face 3a of the housing 3 in its disengaged position.

When the door is closed, a roller 10 provided at the end of the drive member 9 engages with either the door frame or the door depending on whether the housing 3 is mounted in the door or the door frame respectively, to move the restraint driving member into an engaged position. The restraint driving member 9 is movable translationally and its movement is restricted by a pin 11 provided in a slot 12 within the restraint driving member 9.

The restraint driving member has an arm 13 extending laterally over and under the lock member 1 to the other side thereof. The arm 13 is provided to couple with the restraint mechanism.

The restraint mechanism comprises a restraint member 14 and a bistable plate 15. The restraint member 14 is biased towards a restraining position by a spring 16.

To co-operate with the restraining mechanism 14, 15 and 16, the lock member 1 has an extended side region 17 which forms a shoulder 18 and a side face 19.

The restraint member 14 is held pivotably on a pivot 20 to allow it to pivot between a restraining position and a releasing position. The restraint member 14 has a first arm which is arranged to engage the shoulder 18 of the lock member 1. This engagement of the first arm is provided by a roller 21 which can roll along the side face 19 into a restraining position on the shoulder 18. The restraint member 14 also has a second arm on the other side of the pivot 20 which has a restraint release pin 22 mounted thereon for the manual release of the restraint mechanism.

The restraint member 14 carries the bistable member 15 such that the bistable member 15 is pivotably mounted on the restraint member 14 by a pivot 23.

The restraint member 14 comprises two parallel plates 14a and 14b. The bistable member 15 also comprises two parallel triangular plates 15a and 15b mounted on the outside of the plates 14a and 14b of the restraint member 14. The pivot 23 of the bistable member 15 is mounted at an apex of the triangular plates 15a and 15b. A first pin 24 is mounted at another apex of the plates 15a and 15b in a position to couple with the arm 13 of the restraint driving member 9. The first pin 24 of the bistable member is arranged to slide within guide slots 25 within the plates 14a and 14b of the restraint member 14. A further pin 26 is provided between the third apex of the plates 15a and 15b and lies at a position outside the plates 14a and 14b of the restraint member 14.

The bistable member 15 is also provided with a peg 27 to engage with the shoulder 18 of the lock member 1 through a slot 28 in one of the plates 14a of the restraint member 14.

The restraint member 14 is thus rotatable about the pivot 20 between a restraining position and a releasing position. The bistable member 15 is movable between two positions, an electrically driven position and a manually driven position by rotation about the pivot 23.

Manual override means is provided in the form of two coaxial cams 29, 30. The first cam 29 is provided with a short arm. The first cam 29 has a slot 29a provided at a position along its axis for the insertion of a tang of a key cylinder 44. The first cam is thus manually rotated by a key inserted in the key cylinder.

Coaxially mounted with the first cam 29 is a second cam 30 having a long arm. Mounted on the long arm of the second cam 30 is a peg 31 for engagement by the short arm of the first cam 29 when the first cam 29 is rotated by a key in a first direction to manually unlock the lock mechanism. The short arm of the first cam 29 is thus arranged to pick up the second cam 30 via the peg 31 when the first cam 29 is rotated in a first direction. The first cam 29 is also arranged to engage with the peg 22 on the restraint member 14 when the first cam 29 is rotated in a second direction to unlock the lock mechanism manually using a key.

The extended side region 17 of the lock member 1 is provided with a flange 32 which has a face for engagement by an electrically driven means to drive the lock member 1 from an engaged position to a disengaged position.

The electrically driven means comprises an electric motor 33 driving a gear box 34. The output shaft 35 of the gear box 34 has mounted thereon an arm member 36 for engagement with the flange 32 of the lock member 1. In order to reduce friction, the arm 36 of the electrically driven means has mounted thereon a roller 37 such that as the shaft 35 and thus the arm 36 is rotated, the frictional force between the arm 36 and the flange 32 is reduced by the presence of the roller 37.

The electrically driven means also includes an electrical drive switch arrangement 38 to detect the position of the electrically driven means. The electrical drive switch arrangement 38 comprises a pair of switches 38a and 38b which co-operate with the lugs 39a and 39b provided on the arm 36.

In order to monitor the position of the lock member 1 there is also provided a lock switch arrangement 40 which comprises a lock switch 40a which co-operates with a lug 41 mounted on the side face of the lock member 1.

Electrical signals from the lock switch 40 and the electrical drive switch arrangement 38 can be passed by wires (not shown) to an electrical feedthrough 42 to allow the passage of the signals through the housing 3.

Within the extended side region 17 of the lock member 1, there is provided a pivotable end force peg 43 which drops under the action of gravity or a spring (not shown) to extend from the side face 19 of the lock member 1 when the lock member 1 is electrically driven in either its engaged position or its disengaged position. The extending part of the end force peg 43 engages with one side of the arm 36 of the electrically driven means such that the arm 36 of the electrically driven means is retained between the flange 32 of the lock member 1 and the extending end of the end force peg 43. The end force peg 43 can be retracted from its extending position to within the extended side region 17 of the lock member 1 when the lock member is moved to its disengaged position by the manual override means.

The first cam 29 is provided with a square aperture 29b to allow the insertion of a lever to exert a significant amount of force to drive the manual override means. When the lever is inserted in the first cam 29, the manual override means can be rotated in both the first and second directions to drive the lock member 31 between the engaged and disengaged positions. The second cam 30 is also provided with a square aperture 30a to enable a lever to be inserted from the opposed face of the lock mechanism. When the lever is inserted within the square aperture 30a of the second cam 30, the manual override means can be driven in a first direction only to drive the lock member 1 from an engaged position to a disengaged position.

Figure 6 illustrates a cover plate 45 which fits onto both sides of the housing 3 and is secured thereto by suitable security screws through screw holes 45a, 45b, 45c and 45d. The cover plate includes a cylinder plate 46 mounted on the cover plate 45 by suitable security screws fitting through screw holes 47a, 47b and 47c. The cylinder plate 46 has an aperture 48 through which a tang of a conventional key cylinder can protrude to locate with the axial slot 29a in the first cam 29. The cylinder plate 46 is also provided with screw holes 49a and 49b to allow the attachment of the key cylinder 44 to the cylinder plate 46. In order to gain access to the apertures 29b and 30a to enable a large force to be applied to the manual override means during for example a siege situation, the cylinder plate 46 can be removed by undoing the screws in holes 47a, 47b and 47c.

Figures 1, 2 and 3 illustrate the lock mechanism in three different states. The operation of the lock mechanism both electrically and manually will thus now be described with reference to Figures 1, 2 and 3.

Figure 1 illustrates the configuration of the lock mechanism when the lock mechanism is in a locked and shut door state achieved by electrical operation.

In this state the electrically driven means is arranged such that the arm 36 has been rotated to a forward position allowing the lock member 1 to move to its engaged position under the action of the spring 6.

The restraining mechanism is released since the restraint drive member 9 is in its engaged position and the arm 13 is coupled to the restraint mechanism to drive it to a released state. In this released state the arm 13 couples with the pin 24 of the bistable member 15 to bias the restraint member 14 clockwise about the pivot 20 against the biasing force of the spring 16. The roller 21 on the first arm of the restraining member 14 is thus made to roll along the shoulder 18 until it is disengaged with the shoulder 18. The spring 6 of the lock member 1 then moves the lock member 1 into its engaged position whereupon the roller 21 rolls along the side face 19 of the lock member 1.

Thus, when the door is shut, the arm 36 of the electrically driven means can rotate to act on the flange 32 of the lock member 1 to urge it into a disengaged position. When it is in a disengaged position, the arm 36 of the electrically driven means holds the lock member 1 in its disengaged position.

Thus, even if the door is shut and the restraint member 15 disengages the shoulder 18 of the lock member 1, the lock member 1 is still held in a disengaged position. If the door is opened, and the restraint drive member 9 moves to its disengaged position, the lock member 1 is still held in its disengaged position by the arm 36 of the electrically driven means. Thus, when the door is shut and the electrically driven means is in its disengaged state, the lock member is restrained not only by the arm 36 of the electrically driven means but also by the restraining mechanism.

Referring now to Figure 2, this illustrates the configuration of the lock mechanism when the door is closed and the lock member 1 has been manually disengaged by the manual override means. In this configuration, by insertion of a key into the cylinder 44 and thus by the action of a tang within the slot 29a in the first cam 29, the short arm of the first cam 29 is moved to engage the peg 31 on the long arm of the second cam 30. Thus rotation in a clockwise direction of the first cam 29 causes the second cam 30 to be picked up via the peg 31. The peg 31 then engages the pin 26 on the lower apex of the bistable member 15 to rotate the bistable member 15 anticlockwise about its pivot 23 such that the pin 24 at its upper apex decouples the restraint mechanism from the arm 13 of the restraint drive member 9.This rotation of the bistable member moves it from an electrically driven position to a manually driven position and decouples the restraint drive member 9 from the restraint mechanism. Further rotation of the first and second cams 29, 30 causes the end of the long arm of the second cam 30 to initial engage the end force peg 43 to cause it to rotate about its pivot and retract within the arm 17 of the lock member 1, thus disengaging it from the arm 36 of the electrically driven means. In this way the end force protection is removed allowing the lock member 1 to be moved from its engaged position to its disengaged position. Further clockwise rotation of the first and second cams 29, 30 causes the end of the long arm of the second cam 30 to engage the shoulder 18 of the lock member 1 to apply a force to urge the lock member 1 from its engaged to its disengaged positions.

Thus Figure 2 illustrates the configuration when the lock member has been manually retracted. The electrically driven means is still in its engaged state. The manual override means will only operate so long as the electrically driven means is in this engaged state. If the arm 36 is in engagement with the flange 32 of the lock member 1, the lock member 1 is retracted and cannot be moved to its engaged position by manual force against the force of the electrically driven means.

Figure 3 illustrates the configuration of the lock mechanism when the electrically driven means is in its disengaged position. The arm 36 is rotated to a rearward position thus holding the lock member 1 in its disengaged position via the flange 32. In this position the restraint mechanism can additionally restrain the lock member 1 but release of the restraint mechanism will not allow the lock member 1 to move to its engaged position. Only the movement of the electrically driven means to its engaged state will allow the extension of the bolt member 1 to its engaged position.

As can be seen in the drawings, the provision of the restraint drive member 9 linked to the restraint mechanism by the arm 13 allows for the lock mechanism to be electrically set in a locked state such that when the door is shut and the restraint drive member 9 operates on the restraint mechanism to release the restraint, the bolt extends to its engaged position to lock the door. This provides for an automatic locking facility when the door is shut. The lock never extends when the door is open since it is always held by the restraint mechanism or in addition by the electrically driven means as can be seen in Figure 3.

In order to provide safety and enable the door to be unlocked in the event of power failure, the manual override means allows the restraint mechanism to be decoupled from the restraint driving member 9 and the retraction of the bolt member 1 to its disengaged position, thus allowing the door to be opened. In order to pass control of the lock mechanism back to the electrically driven means, the manual override means must be operated by rotation of the first cam 29 in the opposite direction to re-couple the restraint mechanism to the restraint driving member 9.

Thus, as can be seen by the above, the present invention allows for the door to be unlocked or locked while still closed but does not use the latch-bolt of the prior art with its inherent weaknesses.

In the present invention, the end of the lock member 1 which engages with the door frame or the door depending on whether the lock member is mounted in the door or the door frame, is provided with a roller.

The roller is provided to reduce the frictional force between the door member and the member to which it engages. Thus, if a force is exerted against the door when is locked, the provision of the roller will reduce the frictional force between the lock member 1 and the member to which it is engaged allowing the easier retraction of the bolt member to its disengaged position.

Further, the provision of the square recess within the first and second cams provides for an additional facility to enable the exertion of a considerable amount of force manually to unlock the lock mechanism and retract the bolt member 1 in the event of a need to exert such force, e.g. in a siege situation. Thus, the combination of the roller 4 and the square recess 29b, 30a within the cams 29, 30 significantly improves the chances of being able to retract thE bolt member 1 in a siege situation.

Figures 9 and 10 illustrate an alternative restraint mechanism of an alternative embodiment of the present invention. As mentioned hereinabove for the previous embodiment illustrated in Figures 1 to 8, once the manual override means has disengaged the lock member 1, the electrically driven means does not have control of the position of the lock member until the manual override means is operated to return control back to the electrically driven means. In the embodiment illustrated in Figures 9 and 10, the electrically driven means is able to recouple the restraint mechanism to the arm 13 of the restraint drive member 9 by moving from its engaged state to its disengaged state.

Figures 9a and 9b illustrate a configuration of the alternative restraint mechanism when the door is closed and the latch member is in its engaged position by operation of the manual override means.

The alternative restraint mechanism comprises a restraint member 140 similar to the restraint member 14 of the previous embodiment without the slot 28.

The bistable member 150 is similar to the bistable member 15 of the previous embodiment except that the peg 27 for engagement with the slot 28 in the bistable member 14 is replaced with a peg 151 for engagement with a bistable latch mechanism of the electrically driven means. The bistable member 150 is biased in a clockwise direction about the pivot 23 by a spring for example which is not shown. Otherwise, the components of the restraint mechanism of this embodiment are similar to the components of the restraint mechanism of the previous embodiment and thus like reference numerals have been used to denote like components.

As can be seen from Figure 9b, the bistable member 150 resides in the same position as the bistable member 15 in Figure 2 when the bistable member is in its manually driven position. However, in this embodiment the bistable member 150 must be held in the manually driven position against the action of the clockwise biasing force. This is achieved by a receiving face in a bistable latch arm 160 which is biased towards the peg 151 extending from a face of the bistable member 150. The biasing of the bias latch arm 160 is achieved by a spring 170 attached to the biasing latch arm and a pin 180.

The biasing latch arm 160 restrains the clockwise motion of the peg 151 of the bistable member 150 but allows restraint mechanism comprising the restraint member 140 and the bistable member 150 to rotate about the pivot 20 between its restraining and releasing positions.

Thus, as can be seen in Figure 9 as long as the electrically driven means is in its engaged state such that the arm 36 mounted on the shaft 35 extends in the direction of engagement of the lock member, the restraint mechanism can be operated by the manual override means and the bolt member can thus be extended and retracted using the manual override means.

Figure 10a illustrates how the bistable latch arm 160 is moved from engagement with the peg 151 of the bistable member 150. When the electrically driven means is moved from its engaged state to its disengaged state the bistable latch mechanism is released. This is achieved by the rotation of the arm 36 on the shaft 35 such that the roller 37 contacts the bistable latch arm 160 to act against the biasing force of the spring 170 to move the bistable latch arm 160 away from engagement with the peg 151 of the bistable member 150. Once the peg 151 has been released by the bistable latch arm 160, the bistable member 150 is free to rotate clockwise from its manually driven position to its electrically driven position under the action of a biasing means such as a spring (not shown).

As the shaft 36 of the electrically driven means is rotated into its disengaged state or rotated back to its engaged state, the bistable latch arm 160 is then allowed to be gently sprung against the face of the peg 151 without restraining it. In this way the electrically driven means is able to recouple the restraint mechanism to the arm 13 of the restraint drive member 9. In order for the manual override means to decouple the restraint mechanism it is simply necessary for the bistable member 150 to be rotated anti-clockwise by the action of the arm of the second cam 30 on the pin 26 of the bistable member 150. As the bistable member rotates counter-clockwise, the peg 151 will ride over the edge of the bistable latch arm 160 so that the bistable latch arm 160 holds the bistable member 150 in its manually driven position.

It can thus be seen from Figures 9 and 10 that this alternative embodiment of the present invention allows for the manual override means to decouple the retraint mechanism from the restraint drive arrangement whilst the electrically driven means can recouple the restraint mechanism to the restraint drive arrangement. Thus even when the lock member has been retracted manually, the electric motor can relock the door without requiring the lock to be manually reset.

Although the present invention has been described hereinabove with reference to specific embodiments, modifications which lie within the scope of the claims will be apparent to a skilled person in the art.

Claims

1. A lock mechanism for fixing to a movable member or frame for locking said movable member in a closed position in said frame, the lock mechanism comprising a bolt member movable between a disengaged position and a engaged position for engagement with said frame or said movable member; a restraining mechanism to engage and restrain said bolt member when said bolt member is in said disengaged position; restraint driving means coupled to said restraining mechanism to engage with said frame or said movable member when said movable member is closed to drive said restraining mechanism to release the restraint on said bolt member; an electrically driven means movable between an engaged state and a disengaged state, said electrically driven means being arranged to be movable from an engaged state to a disengaged state to drive said bolt member into said disengaged position and to hold said bolt member in said disengaged position; bolt urging means to urge said bolt member into said engaged position and to hold said bolt member in said engaged position when said electrically driven means moves to said disengaged state and said restraining mechanism releases the restraint on said bolt member; and manual override means movable in a first direction to drive said bolt member into said disengaged position from said engaged position and to uncouple said restraint driving means from said restraining mechanism to enable said restraining mechanism to restrain said bolt member, and movable in a second direction to drive said restraining mechanism to release the restraint on said bolt member and to recouple said driving means to said restraining mechanism, said manual override means being arranged to be operative only if said electrically driven means is in an engaged state.

2. A lock mechanism as claimed in Claim 1, wherein said restraint mechanism comprises a restraint member connected to a bistable member, said bistable member having an electrically driven position in which said bistable member provides coupling between said restraint member and said restraint driving means, and a manually driven position in which said restraint member is decoupled from said restraint driving means.

3. A lock mechanism as claimed in Claim 2, wherein said bolt member has a shoulder for engagement with said restraint member, said restrain mechanism including a pivot, said restraint member being pivotably mounted on said pivot and pivotable between a restraining position and a releasing position, said biasing means biasing said restraint member towards said restraining position, said restraint member having a first arm member for engaging with said shoulder of said bolt member and positioned on one side of said pivot, said release member comprising a second arm member on the other side of said pivot to said first arm member.

4. A lock mechanism as claimed in Claim 3, wherein said bistable member is movable by said manual override means from said electrically driven position to said manually driven position, said restraint mechanism including biasing means to bias said restraint member towards engagement with said bolt member for restraint of said bolt member when said bolt member is in said disengaged position, and a release member for engagement by said manual override means when driven in said second direction to release the restraint on said bolt member, said bistable member being movable by said bolt member from said manually driven position to said electrically driven position as said bolt member moves from said disengaged position to said engaged position.

5. A lock mechanism as claimed in Claim 4, wherein said restraint member has a second pivot mounted thereon, said bistable member being pivotably mounted on said second pivot, said bistable member being rotatable about said second pivot between said electrically driven position and said manually driven position, said bistable member having a first arm member for engagement with said restraint driving means to couple said restraint driving means and said restraining mechanism when said bistable member is in said electrically driven position, a second arm member for engagement by said manual override means to rotate said bistable member to said manual position as said manual override means is moved in said first direction, and a peg member for engagement with said shoulder of said bolt member to move said bistable member from said manually driven position to said electrically driven position as said bolt member moves from said disengaged position to said engaged position.

6. A lock mechanism as claimed in Claim 3, wherein said bistable member is movable by said manual override means from said electrically driven position to said manually driven position, said restraint mechanism including biasing means to bias said restraint member towards engagement with said bolt member for restraint of said bolt member when said bolt member is in said disengaged position, and a release member for engagement by said manual override means when driven in said second direction to release the restraint on said bolt member, said bistable member being movable from said manually driven position to said electrically driven position when said electrically driven means moves from said engaged state to said disengaged state.

7. A lock mechanism as claimed in Claim 6, wherein said restraint member has a second pivot mounted thereon, said bistable member being pivotably mounted on said second pivot and biased towards said electrically driven position, said bistable member being rotatable about said second pivot between said electrically driven position and said manually driven position, said electrically driven means including a bistable latch mechanism for holding said bistable member in said manually driven position when said electrically driven means is in said engaged position, and for releasing said bistable member when said electrically driven means moves to said disengaged position, said bistable member having a first arm member for engagement with said restraint driving means to couple said restraint driving means and said restraining mechanism when said bistable member is in said electrically driven position, a second arm member for engagement by said manual override means to rotate said bistable member to said manual position as said manual override means is moved in said first direction, and a peg member for engagement with said bistable latch mechanism to hold said bistable member in said manually driven position, said bistable member being biased to said electrically driven position as said electrically driven means moves from said engaged state to said disengaged state.

8. A lock mechanism as claimed in Claim 5 or Claim 7, wherein said manual override means comprises a cam arrangement rotatable by manual force in said first and second directions.

9. A lock mechanism as claimed in Claim 8, wherein said cam arrangement comprises a first cam having a short cam arm and a second cam having a long cam arm, said first and second cams being rotatable about a common axis, said second cam having an extending portion for engagement by said first cam as said first cam is rotated in said first direction to rotationally pick up said second cam and engage said long cam arm with said shoulder of said bolt member to drive said bolt member to said disengaged position, said short cam arm of said first cam being arranged to engage said second cam member of said restraint member when said first cam is rotated in said second direction to release the restraint on said bolt member.

10. A lock mechanism as claimed in Claim 9, wherein said first cam has a slot on said axis of said cams, the lock mechanism including a key assembly having a tang extending therefrom into said slot of said first cam, said tang being rotatable by manual operation of a key when inserted into said key assembly.

11. A lock mechanism as claimed in Claim 9 or Claim 10, wherein said first cam has a recess for receiving a lever for manual rotation of said first cam for operation of said manual override means in said first and second directions.

12. A lock mechanism as claimed in any one of Claims 9 to 11, wherein said second cam has a recess for receiving a lever for manual rotation of said second cam to operate said manual override means in said first direction.

13. A lock mechanism as claimed in any one of Claims 3 to 12, wherein said first arm member of said restraint member includes a roller to allow for the smooth engagement of said first arm member with said shoulder of said bolt member.

14. A lock mechanism as claimed in any preceding claim, wherein said bolt member is moved translationally between said engaged and disengaged portions.

15. A lock mechanism as claimed in Claim 14, wherein an end of said bolt member which engages with said frame or said movable member has roll means arranged to have an axis of rotation perpendicular to the direction of motion of said bolt member and parallel to a direction of insertion of said movable member into said frame as said movable member is moved to said closed position.

16. A lock mechanism as claimed in any preceding claim including an end force latch connected to said bolt member to engage said electrically driven means when said bolt member is in said engaged position to prevent said bolt member being moved from said engaged position to said disengaged position by the application of force to an end thereof protruding from the lock mechanism.

17. A lock mechanism as claimed in any preceding claim, wherein said restraint driving means comprises a driving member movably translationally between an engaged position when said driving member is engaged with said frame or said movable member and a disengaged position, said driving member having roll means at an end thereof which engages with said frame or said movable member and is arranged to have an axis of rotation perpendicular to the direction of motion of said driving member and parallel to a direction of insertion of said movable member into said frame as said movable member is moved to said closed position.

18. A lock mechanism as claimed in any preceding claim, wherein said bolt member has a drive face facing the direction of engagement of said bolt member, said electrically driven means comprising an electric motor coupled to a shaft, said shaft carrying a drive arm extending perpendicularly to an axis of said shaft, said drive arm being arranged to engage said drive face of said bolt member to drive said bolt member from said engaged position to said disengaged position as said shaft rotates.

19. A lock mechanism as claimed in Claim 18, wherein said drive arm has roll means arranged to rotate about an axis parallel to the axis of rotation of said shaft.

20. A lock mechanism as claimed in Claim 18 or Claim 19 wherein said drive arm is arranged to rotate through a half turn to drive said bolt member between said engaged position and said disengaged position.

21. A lock mechanism as claimed in any one of Claims 18 to 20, wherein said electrically driven means includes a gear box arranged between said shaft and said electric motor to reduce the rotation rate of said shaft relative to said electric motor.

22. A lock mechanism as claimed in any preceding claim including an electric switch arrangement to monitor the position of said bolt member and provide a bolt member position signal.

23. A lock mechanism as claimed in any preceding claim including a second electric switch arrangement to monitor the state of said electrically driven means and provide an electric drive status signal.

24. A lock mechanism as claimed in any preceding claim including a third electric switch arrangement to monitor the position of said restraint driving means and to provide a restraint drive position signal.

25. A lock mechanism substantially as hereinbefore described with reference to and as illustrated in any of the accompanying drawings.