Patent GB-890124-A (GB)
Title: Improvements in and relating to locks, more especially mortice and like locks
Inventor: STANTON WILLIAM HENRY
IPC: E05B55/00
Filed: 1959-03-16
Abstract: 890,124. Key locks. CHUBB & SON'S LOCK & SAFE CO. Ltd. Feb. 11, 1960 [March 16, 1959], No. 8985/59. Class 44. A key operable lock incorporates a bolt or latch 26 movable between extended and retracted positions, the freedom for -movement of the bolt or latch or of mechanism whereby the bolt or latch can be retracted being controlled by a linkage of pivoted levers 4, 9 and the operation of said linkage being controlled by a plurality of pivoted gated levers 13 adapted to be selectively positioned by the key in order to permit operation of the linkage and thus retraction by the key of the bolt or latch. In the construction shown in Fig. 9 the sliding latch 26 is retracted by a sliding runner 23 the rear edge of which engages a plate 25 secured to the rear end of the latch. The runner has a recess 24 which is engaged by a projection 19 on a thrower 18 when the thrower is turned by the key in the direction to retract the latch. The thrower is provided with a detent 21 to prevent inadvertent displacement. The levers 4 and 9 which are mounted on pivots 5 and 10 respectively are connected together by means of a pin 11 on the lever 9 which engages a slot 12 in the lever 4. Turning the thrower 18 in the direction to retract the latch causes the projection 19 of the thrower to ride against an inclined step 20 of the lever 4 and lift the lever; the engagement of the pin 11 with the slot 12 causes the lever 9 to rock about its pivot and provided the gated levers 13 are properly aligned causes an abutment 17 on the lever 9 to move into slots 16 of the levers 13. If the levers 13 are not properly aligned the lever 9 cannot move and hence the latch cannot be retracted. The levers 13 are pivoted as usual by the bits of the key. When the thrower is in its normal position the runner is prevented from movement by an abutment 6 on the plate 4 which engages a portion of a slot 7 in the runner. By turning the key in the opposite direction to that which retracts the latch i.e. anticlockwise the runner is moved to the left as shown and the abutment 6 engages a rear section of the slot 7 so that the latch is deadlocked. This facility together with the provision of more than one slot in different positions in some or all of the levers 13 provides for selective key operation by for example a master key, a tenant's key and a servant's key, the master key operating under all conditions and the servant's key being unable to return the runner plate to its intermediate position in which it is in engagement with the plate 25 on the end of the latch. In addition to the engagement of the abutment 6 with the slot 7 deadlocking means are provided for the runner; these comprise a plate 47 vertically slidable in the lock casing and having an upper hook shaped stop 48 and a side arm terminating in a lug 49. The stop 48 is adapted to engage an abutment 50 on the runner 23. When the levers 13 are raised by the key at least one of the levers engages the lug 49 and lifts the plate 47 to enable the runner to be moved by the key leftwards; the abutment 50 then comes beneath the hook 48 and is engaged thereby when the plate 47 falls on completion of the turn of the key. The plate 47 cannot be lifted by the servant's key. The latch can be retracted by a handle, the handle spindle engaging a rotatable boss 27 having an arm 28 which engages a flange 29 on the inner end of the latch 26. A privacy catch is provided to enable the latch to be locked from inside the room; this comprises a spring loaded lever 44 mounted on a rotatable operating shaft 31 and having a stop member 45 at its free end movable into a position obstructing inward movement of the latch. To enable this privacy latch to be released by the master key, a slidable plate 46 is provided which is urged downwards into contact with a projection 41 on the runner. The runnercan move to the right without vertically displacing the plate 46 but if the key is first turned anticlockwise the plate 46 is raised and the privacy latch is moved out of engagement with the latch; the latch can then be retracted in the normal manner by turning the key clockwise. In a modification, the means for releasing the privacy catch by a master key are omitted and in this construction the privacy catch has a slot which engages the plate 25 on the latch; with this arrangement the latch can be fastened by the privacy catch both in its extended and in its retracted positions. In this modification a stud bolt is provided to prevent release of the latch by a thin sheet of material inserted between the fore end of the lock and a door frame or the like; the stud bolt is mounted above the latch and when the latch is extended the stud bolt is in its retracted position since it engages the door frame; in this position a slidable plate which is raised by the stud bolt when in its extended position has a lug located behind the latch to prevent its inward movement. The slidable plate is similar to the plate 46 in the previous construction and is raised in a similar manner when the key is turned, the plate can however also be raised by the arm 28 of the boss 27 when the handle is turned. In a further construction a dead bolt is used instead of a  latch and this is operated directly by the thrower instead of through a runner. In this construction there is no provision for retracting the bolt by means of a handle, the privacy catch is omitted, the deadlocking plate 47 is omitted and there is no provision for selective key operation. The levers 4 and 9 are as in the previous constructions and there is a pack of gated levers 13 as in the previous constructions.