GB618490A - Improvements in door and like latches - Google Patents

Abstract

618,490. Striking plates; door latches. MITCHELL, A. R. Nov. 11, 1946, No. 33432. [Class 44] Striking plates.-The casing and striking plate of a latch, Fig. 5, are provided with tapered ribs and grooves which come into engagement when the door is closed. The ribs 28a on the latch casing are formed on the top and bottom faces of a projecting frame 28 surrounding the bolt and run in the direction of opening and closing of the door. The striking plate comprises a casing 26 and a movable staple block 27 having projecting jaws 27a receiving between them the frame 28 on the latch casing and provided with grooves to accommodate the ribs 28a. The block is movable to accommodate for door drop &c. in the vertical direction and towards and away from the latch but is normally frictionally retained in position by a spring plate 29. The block is formed with a vertical groove to accommodate the spring 29 and to allow it to slide vertically on the spring. The spring is mounted in the staple casing so that it can slide with the block 27 towards or away from the latch. Door latches.-The spring actuated bolt 9, Fig. 1, is retractable by an outside key lock and an inside handle and there is provided a safety device to deadlock the inside handle manually operable by means located on the inner side or on the edge of the door and restorable to the inoperative position by retraction of the bolt by the outside key lock, or from the inner side by use of a key which is preferably that of the lock itself. The device comprises a pawl 17 pivoted at 16 and adapted to engage the latch actuating cams 11 and 13 associated with the inside handle and the outside lock respectively. That part of the pawl 17 engaging the cam 11 is of dovetail shape and engages in a similar shaped recess. That part engaging the cam 13 is of V-shape and engages in a V-shaped recess. Another arm of the pawl has two notches co-operating with a spring-loaded pin 19 which retains the pawl in the operative or inoperative position. The pawl is moved into the operative position by finger pressure on a sliding rod 18 whose end is in an inaccessible position on the edge ofthe door, covered by the staple casing when the door is shut to prevent inadvertent locking. The end is further protected by a thin spring strip 20. In this position the cam 11 on the inside handle' is locked by the dovetailed end but the cam on the outside lock may still be turned and will force the pawl into the inoperative position shown. The pawl may be released from the inside by a sliding bar 21 operable by a button. This is normally locked by two spring-loaded gated tumblers 22 disposed in slots in the bar 21 which are released when the key is inserted in the hole 25. A single spring 24, loads both the tumblers and urges the bar outwardly. Specification 618,492 is referred to.