GB1221413A - Improvements relating to door latches - Google Patents

Abstract

1,221,413. Latches; locks. HUMPHREY & J. FOX & R. H. MORGAN Ltd. 12 Jan., 1968 [14 Jan., 1967], No. 2088/67. Heading E2A. A night latch comprises a bolt 11 which is movable by an operating handle 14 and by a key, through a lock, between a retracted position and a projected locking position and incorporates at its head a ball or roller 13 which when the bolt is in its retracted position projects under spring loading partly out of the latch housing 10, but can be pressed into the latch housing against the spring loading to enable the ball or roller to act as a catch for releasable engagement with the latch keeper, the latch further comprising a key operated element 36 which when the key is turned in the bolt-projecting direction to project the bolt, is moved by the 'key to permit the bolt; to be retracted by the handle when the key is removed from the lock, and which element, when the key is turned further in the same direction dead-looks the bolt in its projectable position if the key is removed from the lock, so that the bolt cannot be retracted by the handle. As shown the bolt is operable by the handle 14 through a crank 18 on which a pin 20 engages a hole 21 in a link 17 having a pin and slot connection 15, 16 with the bolt 11. An arcuate wall 22 surrounding the hole 21 acts as a connecting means and as an abutment for the element 36 which is carried by a hub 35 rotatable by a tongue 34 of a cylinder lock (not shown). The link 17 is loaded by a spring 24 and the bolt is loaded by a spring-loaded plunger 29. In use, the bolt is moveable to the locked or unlocked position by the handle 14 or by a key. In the latter case, rotation of the key beyond the position in which it moves the bolt to its locking position, moves the element 36 out of engagement with the interior of the wall 22 and into engagement with the exterior of the wall. Removal of the key then prevents retracting movement of the bolt by the handle 14.