GB402276A - Improvements in or relating to dead locking latch bolts - Google Patents

Abstract

402,276. Night-latches. ROLLINS & SONS (London), Ltd., 4, Stonecutter Street, Faringdon Street, DAWSON, F., 6, Cloister Road, Acton, and WARD, A. F., 93, Grove Park Road, Chiswick, all in London. Feb. 8, 1933, No. 3906. [Class 44.] A night-latch 1 is blocked by the engagement behind its tail 6 of an upstanding lug 18 on a plate 17 when the latter is turned in the direction opposite to that for withdrawing the latch, its movement in this direction being limited by lugs 19 and 14 on the plate 17 and the follower 9 respectively so that the lug 18 is in a dead-centre position with regard to the latch and the plate 17. The latch is thus blocked against withdrawal by the inside handle 10 and by direct forcing. When the plate 17 is turned in its normal direction by the bar 20 of a revolving barrel lock or directly by a key, the lug 19 co-operates with the lug 14 to turn the follower 9 and thus withdraw the bolt. The end plate 6 of the latch is cut away to allow it to pass the lug 18 during this operation. The movement of the latch is limited by the follower engaging with a stop 13 on the casing and by the end plate 6 engaging between lug 7, 8 on the follower as in Fig. 2.