GB1504753A - Locks - Google Patents

Abstract

1504753 Lock LAPERCHE 14 April 1975 [18 April 1974] 15179/75 Heading E2A In a lock, the opposite sides of a followeroperated latch bolt 4 have a recess 28 to receive a control member e.g. a key and a locking tumbler 26 is movable by the control member between a first position restricting bolt movement and a second position Fig. 1 in which the bolt is freed the locking tumbler being urged into the first position by resilient means, e.g. spring 27. As shown, recesses 15 on the bolt are engaged by arms 14 of levers 11. Bolt 4 is urged to the position shown by springs 21 on levers 11. Followers 5 on opposite sides of bolt 4 are urged to the position shown by compression springs 9. On rotation of either follower 5 e.g. by a handle (not hown), teeth 17 thereon engage teeth 16 on hub 13 of lever 11 and thus withdraw bolt 4 to open the door, etc. Bolt 4 has a slot 19 for sliding on a guide post 20 and an extension 23 which engages an inwardly facing projection 31 on a tumbler plate 26. Tumbler 26 has projections 29 engaging slots in the lock casing for vertical movement. On engagement with the key before it enters recesses 28, tumbler 26 is moved vertically removing projection 31 from the path of bolt extension 23 when the bolt 4 is moved by the key forward to its locked position in which extension 23 abuts projection 24 extending inwardly from the lock casing. Tumbler 26 moves back under the action of spring 27 to replace projection 31 now on the other side of extension 31, preventing withdrawal of the bolt. When the bolt 4 is in its locked position, teeth 16 of lever 11 are out of the path of teeth 17 of follower 5 and cannot therefore be engaged thereby.