GB190624107A - Improvements in Safety Locks - Google Patents

Abstract

24,107. Jacobson, A., and Svensson, E. A. Oct. 29.. Locks, key.-In a night latch, special means are provided for preventing the bolt from being forced back from outside by an instrument inserted between the edge of the door and the frame. To the bolt a is pivoted a tumbler b, on which an arm c on the handle spindle acts to withdraw the bolt. When the bolt is shot to lock the door, the tumbler b rests on the bottom of the casing and engages with a stump h on the casing to prevent the withdrawal of the bolt, except by the operation of the arm c by the knob or the key. Pivoted to the tumbler. b is a plate d the edge k of which is normally above the bottom edge of the tumbler b, being retained in that position by friction. As the arm c is rotated to withdraw the bolt, the end of the arm enters a notch b<3> in the tumbler band pushes the plate d down, relatively to the tumbler, until the edges k, b' are in line. Further rotation of the arm withdraws the bolt, which is retained in that position by a spring e which acts to keep the tumbler b in the raised position shown in Fig. 3. On returning the knob, however, the bolt is shot, the shoulder k of. the plate d rests on the stump h and, by reason of the friction between the tumbler b and the plate d, keeps the former out of the path of the stump h, as shown in Fig. 4, so that as the door is slammed, the bolt can be pushed back by the striking plate. As the bolt is pushed back, the cam-surface on the plate d engages with the stump h to return the plate to its normal position relatively to the tumbler b ; so that as the bolt re-shoots, the tumbler again comes into action as shown in Fig. 1. The plate can be returned to its normal position from that shown in Fig. 4 by turning the arm c in a counter-clockwise direction, but any unintentional motion of the arm c in this direction is prevented by the spring o, the free end of which bears against a projection p on the casing.