Patent GB-550024-A (GB)
Title: Improvements in lock mechanisms
IPC: E05B65/22
Filed: 1941-07-07
Abstract: . 550,024. Latches. BOOTH, J. H., and BOOTH, J. I. July 7, 1941, Nos. 8532 and 14362. [Class 44] A latch bolt particularly for motor vehicle doors is shot by a light spring aided by a stronger loading spring which is rendered inoperative by the initial movement of the boltretracting means so that retraction of the bolt is effected against the action of the light spring only. This action may be effected by both outside and inside operating means, or by the latter only, in which case outside release is effected against the action of both springs. As shown, a light spring 75 acts on one arm of a cranked lever 25 pivoted in the lock casing at 26, the end 24 of this arm engaging in a slot 23 in bolt 16, which is thus shot. The other arm 32 has a lateral lug 33 which normally engages and supports the edge of a U-shaped lever 34 also pivoted at 26. The loading spring 31 is anchored at one end to a fixed lug 21 and at the other to the short arm 30 of a lever 18 mounted for pivotal and sliding movement by pin 28 and slot 27. The long arm 19 rests on lever arm 32 and is normally supported thereby in line with the bolt the end of the arm bearing against the tail of the bolt as shown. Inside release operation is effected by a vertically sliding spindle 37 with an operating knob 40 and a cylindrical enlargement 48 guided in a bush 38 secured to the vehicle window rail 39. The spindle can be rotated to any of three angular positions defined by the snap engagement with one or other of three grooves 45, 46, 47 in part 48 of the end 43 of a spring ring 42 surrounding part 48, which has an aperture through which end 43 engages. Groove 47 is short so that when engaged by the end 43 depression of knob 40 and spindle 37 is prevented. Grooves 45, 46 are long enough to allow depression of the spindle when either is engaged by end 43. The lower end of spindle 37 rests on arm 19 which, when knob 40 is pressed, is moved out of line with the bolt to render spring 31 ineffective and rock lever 25 to retract the bolt against the action of spring 75. Outside operation is effected by a lever one arm 50 of which provides a handle and the other arm 52 engages the free end of lever 34. When handle 50 is pulled, lever 34 is rocked clockwise, Fig. 1, and a shoulder 36 thereon depresses arm 19 to render spring 31 ineffective and retract the bolt, engagement of lever 34 with lug 33 also helping to rock lever 25. If shoulder 36 is omitted arm 19 is not depressed but lug 33 remains effective and the bolt is retracted against the action of both springs. In one angular position the bevelled part 49 of spindle 37 is directed towards lever 34 which is thus allowed a free path for release movement, but in another the unbevelled part serves to block lever 34 and prevent release of the bolt by handle 50, although spindle 37 may be depressed to effect inside operation. In a modification, spring 31 acts on a vertically depending lever replacing lever 18, the lower end of the lever bearing against a projection interposed between the lever and the bolt tail. This projection is formed on a vertically slidable member which is moved downwards by spindle 37 so that the projection moves out of line with the bolt tail from which the action of spring 31 is thus removed, downward movement of the projection also serving to rock lever 25. The first Provisional Specification describes, inter alia, mounting of lever 18 near the lower end of a pivoted link, the provision of a forked lower end to spindle 37 which locks the follower by rotation through 90 degrees, the arrangement of spindle 37 so that it is pushed in the direction in which the door opens, the provision of a flush outside handle, and rendering movement of the outside handle idle when the follower is locked.