GB634246A - Improved door lock with self-locking locking bolt - Google Patents

Abstract

634,246. Door latches. KORESKA, R. J., and AKTIESELSKABET RUKO. Sept. 10, 1947, No. 24891. Convention date, Sept. 11, 1946. [Class 44] A door latch comprises a casing 1, a spring shot bolt 2 and a rotatable cam member 11 adapted, when turned by an outside key or an inside knob, to engage projections 21 on the bolt plate to withdraw the bolt and in the centre position to prevent retraction of the bolt by co-operation with a shoulder 20. When the door is opened, an auxiliary spring-loaded bolt 5 is released so that a catch member 7 pivoted thereon contacts the casing edge and moves into a position to engage a shoulder 8 on the bolt 2 which is thereby retained in an intermediate shot position 21. A spring 17 is connected to draw together the ends of two levers 15, 16 adapted to engage between them a fixed pin 18 and a pin 19 carried on the cam member 11 which is thereby always returned to the centre position. When the bolt is retained in the intermediate position, the cam member 11 is prevented from returning to the centre position by the contact of the inclined side portions 13 with the shoulder 20. If the door is slammed the inward movement of the bolt displaces the cam member and the catch 7 is released by the inward movement of the auxiliary bolt as it engages the striking plate, allowing the bolt 2 to project to its full extent and the cam member to return to the central deadlocking position. Hooks 14 formed on the sides of the cam member are adapted to engage notches formed in the sides of the shoulder 20 to retain the bolt in the fully retracted position when it is forced back by finger pressure when the door is open.