Patent GB-496817-A (GB)
Title: Improvements in or relating to lock or latch mechanisms
IPC: E05B65/08
Filed: 1937-06-09
Abstract: 496,817. Latch mechanism; attaching handles to spindles. SLEIGH, H. L., CHESTON, A. S., and BOOTH, J. H. June 9, 1937, No. 16061. [Class 44] A lock or latch mechanism for sliding doors, of the type having catch mechanism for holding the door open and closed and releasing the door when the handle is moved in the direction in which it is desired to move the door, comprises, for the or each door, catch mechanism for holding the door closed, remote catch mechanism for holding the door open, and control means for releasing each catch on appropriate operation of the handle. Railway corridor doors 5, 6 carry pivoted catches 8, 9, the hooked ends 11 of which engage each other to hold the doors closed. The catch 8 is biassed to the engaging position by a compression spring 42 and the catch 9 by a tension spring 12, each catch having a projection 21 engaging the wall of the casing to limit its movement. The doors may be unfastened by moving either handle in the opening direction of the door, when the corresponding catch is turned about its pivot 41 by a follower 47, thus disengaging the hooked ends 11 and allowing the door to be opened by continued pressure on the handle. For holding the door open separate mechanism, Fig. 3, is provided on the trailing edge of the door. A casing 30 has a striking face 66, to depress a spring-pressed plunger 32 mounted in the door frame, and a hole 40 to receive the end of the plunger. The plunger is disengaged from the hole 40 by a bell-crank lever 28 actuated by the follower 47 through link 43, bell-crank lever 48 and link 26 when the handle is moved in the closing direction of the door. The link 43 has a pin- and-slot connection with the follower 47 so that operation of either catch by the appropriate movement of the handle does not affect the other catch. The springs 12, 42 associated with the catches 8, 9 also act on the links 43 to keep the bell-crank levers 28 normally out of contact with the plungers 32. To lock the doors in the closed position, an arm 50, mounted in the casing on one door and operable by a removable key, has a nose which can be brought into engagement with a clip 52 on the other door. Cover-plates 57, Fig. 5, are provided on each door to prevent dirt from entering the mechanism and to guard the projecting ends of the catches 8, 9. The spacing of the pairs of cover-plates differs so that they nest together when the doors are closed. One handle on each door is permanently attached to its spindle 59, and the other is secured by a pin 65, Fig. 4, which is covered and retained by a slidable sleeve 64, pressed outwards by a spring 63, housed in a socket 62, screwed to the face of the door. The Provisional Specification describes catch mechanism for the trailing edge of the door comprising a bell-crank lever disposed in a vertical plane and having a vertical arm and an horizontal arm, the latter having a downwardly directed nose for co-operation with a striking plate fixed to the frame. The catch is operated by a bar pivoted to the vertical arm of the bell-crank lever and having a pin- and-slot connection with an upwardly directed arm on the follower on the handle spindle. The catches at the leading and trailing edges of the door have separate springs.