Locks

Details Locks Locks

1996-03-25

1998-06-16

Boucher, Darnell M.

Locks

Special application

For closures

70134, 292 36, E05B 5900

Patent

active

057654107

DESCRIPTION:

BRIEF SUMMARY
This invention relates to improvements in locks and is particularly concerned with means for increasing the throw or movement of the bolt of a mortise lock.
The maximum longitudinal movement or "throw" of the bolt of a mortise lock is limited by the width of the lock casing. Where a lock is to be installed in a solid wooden door, for example, the width of the casing is relatively unimportant because there is no restriction on the depth of the recess in the door which is to accommodate the lock casing. However, in the case of a predominately glass door with a surrounding frame of wood or plastics material, the maximum width of the lock casing must be less than the width of the door frame. Typically, the frames of such doors have a width in the region of 50 mm. and the overall width of lock casings which can be installed in such door frames is of the order of 40 mm.
In order to be fitted in such a door frame, the maximum distance from the outside front of the casing to the axis of a cylinder for the lock, is of the order of 28 mm. Such a lock is known as narrow style and the distance from the outside front of the lock casing to the said cylinder axis is commonly referred to as the backset. When such a latch is fitted with a deadbolt, the bolt is conventionally arranged to be driven by a cylinder cam and, with a backset of only 28 mm, the maximum bolt projection, i.e. the distance by which the bolt projects from the front of the casing when the bolt is thrown, that can normally be obtained by direct drive from a cylinder cam is of the order of only 14 mm. This distance is insufficient to provide a secure locking engagement in the framework surrounding the door.
This problem becomes increasingly acute with the use of new materials such as UPVC in which there is a substantial gap between the edge of the door and the surrounding frame. In order to meet the new EEC standard, a throw of 20 mm is required so that the head of the deadbolt projects into a striking plate in the frame for a distance which is sufficient to make the door secure.
The existing narrow style latches have been unable to achieve a deadbolt throw of the order of 20 mm. and the present invention aims to provide a mortise lock with an increased bolt projection or throw for a given width of lock casing.
According to one aspect of the invention, there is provided a lock for a door or the like having a dead lock assembly which comprises a bolt and a drive mechanism adapted to be operated by a key, wherein the drive mechanism comprises a driving link, arranged to be driven by a lever actuated by the key and arranged in turn to drive the bolt, and means for transferring the drive from the driving link to the bolt in such a manner that the movement or throw of the bolt is increased relative to the displacement of the driving link.
The driving link is desirably sandwiched between the bolt and the drive transferring means.
Preferably, the means for transferring the drive to the deadbolt comprise a quadrant having a peg which engages through a slot in the driving link and into a slot in the bolt.
The quadrant is desirably pivotally connected to the driving link and is provided with guide means for guiding its pivotal movement in the casing.
The driving link is preferably provided with guide means for ensuring that said link moves only in a longitudinal direction substantially parallel to the movements of the bolt.
The lock according to the invention desirably includes a spring-loaded detainer and means for providing an engagement between the detainer and the bolt, the detainer being urged by the spring to a position in which the engagement means are effective to immobilise the bolt in its thrown or locking position. Preferably, the engagement means comprise a detainer pin on the bolt which is engageable in a slot in the detainer, the slot having such a configuration that the pin is retained in a fixed position in the slot by the spring when the bolt is in the thrown or locked position.
The lock according to the invention preferably also includes a cylinde

REFERENCES:
patent: 2380708 (1945-07-01), Schlage et al.
patent: 3175376 (1965-03-01), Cantwell
patent: 4606203 (1986-08-01), Esser
patent: 4688406 (1987-08-01), Horgan, Jr.
patent: 5265920 (1993-11-01), Kaup et al.
patent: 5301525 (1994-04-01), Doring

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