GB597962A - Improvements in and relating to latch bolt hold-backs - Google Patents

Abstract

597,962. Latches. TRIGGS, W. W. (Yale & Towne Manufacturing Co.). July 17, 1945, No. 18326. [Class 44] A spring-shot sliding latch-bolt is held in retracted position (as, for example, where a night-latch is used as an optional additional door fastening which can be put out of action. when desired) by a button-operated device biassed to release position by a spring and held in engagement against the action of said spring by co-operation of the device with the part of the bolt which it engages under action of the bolt-shooting spring. With this arrangement release is effected by giving the bolt a slight retractive movement to disengage the cooperating parts, whereupon the button-operated device is moved to release position by its spring; The bolt then shoots under the action of its spring when the handle is released. As shown the bolt 11 with tail-piece 25 slidably guided in a easing 10 is shot by spring 12 and retracted by handle-operated follower-arm 14 with a cam-pin 13 engaging a slot in the bolt tail as shown. The handle 15 is formed so as to be operable as a thumb-turn. The button 16, slidable in the front wall of the casing, is disposed away from the handle 15 and has riveted to its inner end a plate-spring 20 transversely disposed within the casing and having its ends anchored in notches. The spring is bowed to hold the button in its outermost position, Fig. 3. Also riveted on the button under spring 20 is a plate 19 having at its rear edge an upstanding lug bent to provide a rearwardly-directed hook-like part 23 adapted to engage a notch 26 in the forward edge of a lug 24 upstanding from and integral with the bolt tail. Fig. 3 shows the bolt in its normal released and operative position. If the bolt be retracted and the button then pushed in and held whilst the handle is released, notch 26 engages hook 23 under action of the spring 12 as in Fig. 5, the bolt being held retracted and the button-operated member held in engaged position. To effect release, the bolt is given a slight retractive movement by handle 15 to disengage notch 26 from part 23 whereupon the button is returned to release position by spring 20, and the bolt shoots when the handle is released so that the parts are restored to the normal condition, Fig. 3. A modification is described in which the button is slidable in a bore in the handle, is pressed outwards by a coiled spring, and the button-operated device is a plunger, the inner end of which enters the slot in the bolt tail when the bolt is retracted and the button pushed in. The rear edge of the slot engages in a lateral slot near the inner end of the slot engages in a lateral slot near the inner end of the plunger under action of the bolt-shooting spring to retain the plunger and button in engaged position.