GB487535A - Latch - Google Patents

Abstract

487,535. Latches. WILSON, E. C., WILSON, E. P., FARRAR, E. J., and BOOTH, A. B. April 21, 1937, No. 11440. Convention date, April 21, 1936. [Class 44] A latch mechanism has a single oscillatory latching arm 31 adapted to co-operate with a keeper 11 together with a catch member 49 which holds the arm in a partially open position until released by the engagement of the arm with the keeper. The end of the arm 31 carries a wrist pin 32 supporting a roller 33 which co-operates with the surface 23 of the keeper 11. The surface 23 is so shaped that the door 16 is drawn onto its sealing gasket at first quickly and then slowly. The arm 31 is carried by a shaft 29 to which is attached a bifurcated portion 38, and the handle 40 is free to rotate on this shaft. To release the latch from the closed position shown in Fig. 5 the handle 40 is moved outwards and the face 42 engaging shoulder 43 of the lug 52 attached to the portion 38 causes the crank-arm 31 to be swung sufficiently to bring the roller 33 clear of the keeper. To hold the crank-arm in the partially open position against the action of springs 34 a catch member 49 is provided comprising a spring loaded detent bar 49a pivoted at 50. When the handle 40 is moved outwards sufficiently to release the crank-arm 31 a connecting spring 55 causes the arm 49a to be pulled down against the spring 53 so that the lug S on the member 38 may engage an opening 51 therein. The spring 55 has an elongated hook connection 56a with the bar so that arm 49a does not commence to move until the handle has been partially opened. When the lug S has engaged the opening 51 the handle is released and returned to the closed position by the spring 45. If the door is now slammed the nose of the keeper will cause the arm 31 and lug S to rotate clockwise which will allow the catch member 49a to return to its inoperative position under the action of the spring 53 and this in turn will allow the powerful springs 34 to pull the arm 31 into the keeper 11. The catch member may be pivoted in front of the latch, and an horizontal spring used.