GB1425897A - Door latches - Google Patents

Abstract

1425897 Latching mechanisms WEST ALLOY DIECASTINGS Ltd 28 March 1974 [29 March 1973] 15236/73 Heading E2A A door latching mechanism in which radial downward and upward swinging movement imparted to a door lever handle 8 to retracts or projects the spring-loaded latch 2, movement of the latch by the handle is effected through the intermediary of a ball or roller 5 allowed to fall by gravity from a cavity 1A in the latch casing into a cavity 7A in one face of an actuating cam 7 movable by the handle so as to co-act with the latch to retract the latter against the influence of a spring or springs 3. The arrangement is such that the ball can be made to occupy an inoperative position in the casing in which it permits the latch to be urged by the spring 3 into a projected latching position, or alternatively, a position in which it transmits movement to the latch to retract the latter into the latch casing 1, the ball and its associated mechanism being duplicated as an identical mirror image both at the top and bottom of the latch casing so that according to which side of the latch is disposed uppermost (to suit right or left hand hanging of the door) one of the balls and its associated mechanism is rendered operable and the other inoperable. As shown, the ball 5 is disposed in the recess 7A in the cam 7 and a recess 2A in the side 2C of the latch 2, movement of the lever 8 downwardly causing the ball to transmit movement from the cam via the ball to the latch to retract the latch; release of the handle allows the spring 3 to project the latch. Upward movement of the handle turns the cam to allow the ball to move freely in the recess 2A and to bring the cam face 7C into contact with the face 2E of the latch whereby the latter is restrained from retraction; release of the latch is effected by moving the handle to the neutral position. Resistance to movement of the cam 7 and handle to the neutral and snib positions is provided for by a spring-loaded ball 9 engageable in recesses 1C, 1D and 1E. For operating the latch from the exterior of the door the cam and lever can be turned by inserting and rotating a blade, e.g. forming an integral part of a key-operated barrel lock, through a hole in a cam 12 and a hole 8A in the handle; the cam 12 and balls 10, 11 constitute the means for operating the latch from the exterior of the door.