Patent GB-297614-A (GB)
Title: Improvements in or relating to locks
IPC: E05B17/18
Filed: 1928-01-04
Abstract: 297,614. Myers, M., and Needleman, P. Jan. 4, 1928. Keyholes, obstructing; latches, sliding; locking sliding latches; lock mechanism, lever-type; multiple-bolt fastenings.-In a lock having keyhole obstructing means the obstruction device normally extends across the keyhole and is adapted to be moved by a rotary device operated by the key used to operate the lock mechanism. The lock case a has two plates a', a<2> between which the plate b (with a projection b<2> normally extending across the keyhole c) and its operating means are housed. Plate b is slidable and is held in one or other of its two positions by a spring catch d engaging a. recess b<3> or b<4>. Plate b is operated by a projection e<1> on a rotary plate e carried by a slotted tube g, the tube g being held so that the slot is in position to allow insertion of the key bit by a. recessed spring-pressed plate f engaging the projection e<1> but yielding when a sufficient force is applied. When the lock key is inserted in the tube g and keyhole and rotated, the tube is rotated by the key-bit engaging the side of the slot. Projection e<1> is thus first released from the catch f and then engages a projection d<2> on catch d to release, plate b, plate b being then moved by projection e<1> co-operating with a recess b<5> in plate b. When projection b<2> has been moved clear of the keyhole, the key is inserted further and again rotated to operate the lock. The lock described comprises a latch bolt m with bevelled nose-piece m<1> urged to the shot position by a spring s and withdrawn by a, followex u<1> engaging a tail-piece m<2> on the bolt and operated by the square spindle v of a handle (not shown). The latch bolt may be locked in shot position by a key-operated bolt 1 guided by an opening 2 in the casing a and by a slot 3 engaging a pin 4 on the latch bolt m. The bolt 1 is held in its extreme positions by a square projection on spring-levers 11 (four shown) engaging one or other of recesses 7<a>, 7<c> at the ends of a slot 7 in bolt 1. The bolt is operated by the key engaging the surfaces 11<b> of the levers 11 to release projection 8 from the recess, and then co-operating with a recess 6 in the bolt. The slot 7 has an additional recess 7<b> so that if, with the bolt in shot position, the levers 11 are moved too far by the use cf an improper key, projection 8 engages recess 7<b> and the bolt is retained shot. When shot, a shoulder 5 on bolt 1 engages behind the nose-piece m<1> of the latch and prevents its withdrawal. The tail of the bolt 1 extends out of the casing a and may be utilized to effect other operations. As shown, the tail carries a plate 1<a> with cam slots used to operate additional bolt fastenings as described in Specification 297,615. Ready access to tube g and keyhole may be prevented by the use of a box 15 let into the outer face of the door r and having a lid (shown open), Fig. 9, carrying a suitable catch. As shown, the lid carries a spring-shot catch 17<c> adapted to engage a recess 17<b> in the wall of box 15. The catch is withdrawn by a projection 18<a> on a rotatable member 18 having a rib 18<b> accessible through an aperture in the lid and engaged by a slot in the end of the stem of the lock-key by which member 18 may be rotated.