GB2257466A

GB2257466A - Lock mechanism and method for securing a lock.

Info

Publication number: GB2257466A
Application number: GB9213656A
Authority: GB
Inventors: Marek Glowacki; Artur Litwinski
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-06-27
Filing date: 1992-06-26
Publication date: 1993-01-13
Anticipated expiration: 2012-06-26
Also published as: GB9213656D0; PL290831A1; PL166365B1; GB2257466B

Abstract

In order to prevent a locked door from being opened from inside a building or room, a lock mechanism is provided which comprises external and internal release means, and a slidable locking bolt provided with linked rack portions 1, 2 pivotally mounted thereto. The portions are engaged by pins 5, 7 on the external 6 and internal 8 release means causing rack and bolt movement in direction X and rack movement in direction Y about the pivotal mounting on the bolt. When the bolt is extended, further movement of the external release means 6 places pin 5 into the Position shown against a detent 4. This restrains both rack portions against movement in direction Y and prevents operation by the internal release means 8. <IMAGE>

Description

LOCK MECHANISM AND METHOD FOR SECURING A LOCK This invention relates to a lock mechanism for securing a lock, particularly to prevent opening of a door from the inside of a building or room, and a method for securing a lock.

Known methods of securing locks include providing that opening a lock from inside is possible only after previously pushing in a handwheel. Another known solution relies on the use of a conical handwheel. These solutions secure a lock from being opened by using the so-called 'reins" method, whereby a wire or rope is used to remotely release the interior handwheel. These methods however permit a thief to open the door from the inside once he has broken into a locked room, through a window for instance. To prevent the lock from being opened from the inside, a drumshaped insert is provided inside the handwheel, however, this solution is expensive.

It is an object of the present invention to overcome at least some of the shortcomings of prior locks. In particular, to reduce the likelihood of a lock being opened using the "reins" method.

According to a first aspect of the invention, a lock mechanism comprises external and internal release means, and a slidable locking bolt, wherein the external release means includes a rotatable shaft which carries a bolt-actuating pin spaced from the axis of rotation of the shaft, wherein the bolt is associated with a rack member which is movable in a locking direction transversely of the axis as well as in another direction generally perpendicular to the locking direction, the rack member having a recess or recesses for receiving the pin when the shaft is rotated and for transmitting transverse motion of the pin to the bolt, wherein the rack member is also engageable by the internal release means for imparting transverse motion to the bolt, wherein the rack member has a detent portion arranged to be engaged by the pin only after the rack member has been driven in the locking direction beyond an intermediate locking position, the engagement of the detent portion by the pin, restricting movement of the member in the said other direction, and wherein the relative arrangement of the internal release means and the rack member is such that when the pin engages the detent portion and the shaft has been rotated to a deadlocking position, the restriction on movement of the rack member in the second direction precludes the imparting of transverse motion to the bolt by the internal release means.

The detent portion preferably extends in a plane parallel to that of the rack member and may be formed integrally with the rack at one end of it. The rack member is preferably biassed toward the pin thus enabling the pin to remain in engagement with the appropriate recess as it is caused to traverse an arc when the shaft is rotated.

According to a second aspect of the invention, a method of preventing a lock from being opened by internal release means, after locking by external release means is provided wherein movement of a rack member for transporting an external drive to a locking bolt, or external and internal drive to the bolt, generally perpendicular to the rack member, is blocked by means of a detent portion.

According to a third aspect of the invention, a device for securing a lock comprises a rack member for transmitting an external drive to a bolt, or external and internal drive to a bolt, wherein the rack member comprises a first toothed element (2) and a second toothed element (3), a detent portion (4), which is supported on a pin (5) mounted on a plate (6), which is turned by the external drive, the detent portion being operable to block the rack member from transmitting the drive.

The invention will now be described by way of example with reference to the drawing which is a diagrammatic perspective view of a lock mechanism.

Referring to the drawing, a rack member 1 comprises two upper edges 2 and 3 having teeth, the layout of teeth on the upper edge 2 is terminated in an upper portion by a detent portion 4, lying in the same plane as a plate comprising the edge 2. The rack is biassed generally upward by a spring 9 and teeth of edge 2 engage with an actuating pin 5 mounted on a plate 6, which is rotated by a key (not shown), through the lock's mechanism. The teeth of the edge 3 engage with a second actuating pin 7 mounted on a plate 8, which is rotated by a handwheel (not shown). By turning the key twice, thereby securing the lock, the pin 5 is moved to a position under the detent 4. This prevents the rack which transmits the drive to the bolt in the direction X, from being shifted in the Y direction. Since the pins 5 and 7 are offset from the axis 5 of shafts on which the plates 6 and 8 rotate, the pins traverse an arc as the shafts are rotated. Thus by preventing movement in the Y direction, the pins 7 are prevented from moving which thus prevents the lock from being opened by means of the handwheel.

The lock may be bolted by turning the key once or twice. By turning the key once, the lock may be unbolted from inside by the handwheel since the pin 5 is not beneath the detent portion in this position. By turning the key twice, the device is blocked or deadlocked and the lock may not be unbolted from the inside. Attempted opening by force may damage the handwheel, but the lock will remain bolted. The lock may also be bolted from the inside with the handwheel.

The lock may be unbolted with the key from outside in any position.

Claims

1. A lock mechanism comprising external and internal release means, and a slidable locking bolt, wherein the external release means includes a rotatable shaft which carries a bolt-actuating pin spaced from the axis of rotation of the shaft, wherein the bolt is associated with a rack member which is movable in a locking direction transversely of the axis as well as in another direction generally perpendicular to the locking direction, the rack member having a recess or recesses for receiving the pin when the shaft is rotated and for transmitting transverse motion of the pin to the bolt, wherein the rack member is also engageable by the internal release means for imparting transverse motion to the bolt, wherein the rack member has a detent portion arranged to be engaged by the pin only after the rack member has been driven in the locking direction beyond an intermediate locking position, the engagement of the detent portion by the pin restricting movement of the member in the said other direction, and wherein the relative arrangement of the internal release means and the rack member is such that when the pin engages the detent portion and the shaft has been rotated to a deadlocking position, the restriction on movement of the rack member in the second direction precludes the imparting of transverse motion to the bolt by the internal release means.

2. A mechanism according to claim 1, wherein the detent portion extends in a plane parallel to the plane of the rack member.

3. A mechanism according to claim 1 or 2, wherein the detent portion is integral with the rack member and is formed at an end of the member.

4. A mechanism according to any preceding claim, wherein the rack member is biassed towards the pin.

5. A method of preventing a lock from being opened by internal release means, after locking by external release means, wherein movement of a rack member for transporting an external drive to a locking bolt, or external and internal drive to the bolt, generally perpendicular to the rack member, is blocked by means of a detent portion.

6. A method according to claim 5, wherein blocking of the movement of the rack is obtained by means of supporting a blocking pawl or detent portion on a dog plate or bolt-actuating pin of the external drive.

7. A device for securing a lock, comprising a rack member for transmitting an external drive to a bolt, or external and internal drive to a bolt, wherein the rack member comprises a first toothed element (2) and a second toothed element (3), a detent portion (4), which is supported on a pin (5) mounted on a plate (6), which is turned by the external drive, the detent portion being operable to block the member from transmitting the drive.

8. A method of preventing a lock from being opened substantially as herein described with reference to the drawing.

9. A device for securing a lock constructed and arranged substantially as herein described and shown in the drawing.