GB216311A - Improvements in locks - Google Patents

Abstract

216,311. Lindberg, J. W. May 3, 1923. Latches, sliding; night-latches and like spring locks.-A follower-retracted spring-shot sliding latch is held in its intermediate or latching position by pin-and-slot engagement between it and its follower. Slamming of the door releases the follower to allow the bolt to shoot fully into lock-. ing position. The bolt comprises a head 1, shank 4 and nut or washer 5, perforated flanges 6, 7 on a plate 8 being engaged by the shank 4 to cause the plate to move with the bolt. Extensions 9 of the plate slide on a fixed rod 10 supported by lugs 11 on the casing and carrying the bolt-operating spring 12. The follower 13 is pivoted at P and has a spring 14 tending to throw it to the right. A pin 15 on the follower engages an L-shaped slot 16, 18 in the bolt-plate 8. Fig. 3 shows the bolt in its latching position, the pin 15 engaging a shoulder 21 at the corner of the L-shaped slot and preventing further outward movement of the bolt. In operating the bolt by the handle, the pin travels down the slot 18, withdrawing the bolt, and when the handle is released, the pin is again stopped when it reaches the shoulder 21. When the door is slammed, the bolt is pressed inwards, disengaging the shoulder 21 from the pin 15, allowing the spring 14 to flick the follower to the right, bringing the pin 15 into the large slot 16 and allowing the bolt to shoot out fully into the locking position. The bolt is withdrawn from this position by the follower, the pin 15 pressing on the shoulder 17 and snapping into the slot 18. When the bolt is in the fully shot position, an extension 26 on the follower engages behind the lug 25 on the bolt plate to prevent withdrawal by forcing. Lost motion occurs between the pin 15 and shoulder 17, in withdrawing the bolt, to ensure that the extension 26 is lifted clear of the lug 25 before the bolt begins to move inwards. A guide-pin 22 fixed to the casing co-operates with slots 23, 24 in the follower and bolt-plate respectively. A finger-operated stop 27 with a neck 29 pressed into an upper or lower side recess in a slot in the casing wall 3 by a spring 31, may be employed to hold the bolt in either of its extreme positions. The follower 13 may be operated from outside by a key.