GB641335A - Improvements in and relating to locks for doors and the like - Google Patents

Abstract

641,335. Night latches. THORNE, H. Aug. 20, 1948, Nos. 21958/48. and 6591/49. [Class 44] A night latch comprises a spring urged bolt and a cam track associated therewith in which rides a detent caused to move round the track in the same direction, successively to retain the bolt in a half-shot position and to allow it to be fully shot. In the form of Figs. 1 and 2 the bolt 5 is formed with a part 6 of box form in which is a horizontal plate 28 carrying a U-shaped member 27 and a blade spring 26 the end 26<1> of which is free. The detent is formed on the end of a rod 13 having a vertical limb pivoted at 14 to the casing 1 and an arm 12 to which is attached a spring 9. The free end 25 of the wire is adapted to cooperate with the notch 27 and the spring 26 to control motion of the bolt as follows. In the fully shot position (shown) the detent lies over the end of the' blade spring 26 and, when the bolt is retracted by an outside 'key lock 30 or an inside sliding handle 19, slides up and falls on a pin 29 projecting from the bolt. When the handle is released the detent engages in the notch 27 to hold the bolt in the half shot position (shown in dotted lines). When the door is slammed the bolt is pressed in by the rounded nose 16 engaging the edge of the keeper, and this movement allows the detent to pass out of the notch and slide back along the inner face of the box 6, passing under the free end of the blade spring 26 into the initial position. The bolt may be formed with rounded surfaces on each side to suit right- or left-handed doors. The handle spindle 18 passes along a slot 20 in the casing and may deadlock the bolt in the fully shot position by engagement in one of the side slots 21. The spring 9 is attached at 15 to the box 6 and serves to shoot the bolt. The outside key lock 30 carries a follower 32 engaging a plate 33 to retract the bolt. In the form of Fig. 4. a detent arm 43 pivoted to the casing carries a pin 44 riding in a cam slot 45 formed between an opening in the bolt plate and a body 48, part 49 of which is pivoted at 50 to provide a non-return gate ensuring that the pin always passes round the cam slot in the same direction. The action is similar to the form above, the pin being received in the slot 46 in the fully shot position of the bolt and in the notch 47 in the half shot position. A deadlocking pawl 59 engaging in a notch 60 is released by the initial movement of the key lock follower 61 before it engages the abutment 37 to retract the bolt.