GB601185A - Combination mechanism for locks - Google Patents

Abstract

601,185. Permutation locks. KETNER, L. P. G. Oct. 19, 1945, No. 27527. Convention date, Nov. 14, 1944. [Class 44] Permutation lock mechanism of the kind in which each of a number of push rods 2 carrying pins 3 have to be set in predetermined positions, comprises a series of plates 4 . . . 8 sliding laterally in guides in the casing, and actuated to operate the lock by means of a member 22 pivoted at 21. The plates 4 and 8 are plain; plate 5 has openings 24 through which the pins 3 pass, with slots 25 extending therefrom which permit movement of the plate when the pins are opposite the slots ; the plate 6 has openings 26, each having three (or more) incisions 27 corresponding to the possible positions of the pins, which during initial movement of the plates lock the pins to prevent further manipulation to open the lock by feeling. Plate 4 is a cancellation plate in which the openings 28 are shaped as shown to bring all pins to the central position on locking. The plates are moved by the member 22 through cam surfaces thereon acting on projections 19, 29, 30 on the plates. To unlock after setting the push rods, the member 22 is. turned anti-clockwise, when the plate 5 is moved to the left by contact of the ledge 20 with the projection 19 on plate 5, carrying plate 4 with it through contact of a flange 13 on the latter with the end of the plate 5. At the same time the locking plate 6 is allowed to move under the influence of a spring 17. Plates 7 and 8 remain stationary during unlocking. When the member 22 is released, it is turned counter-clockwise by pressure of the projection 19 against the edge 20, and the plates 7, 8 and 9 are then free to move to the left under the influence of a spring 40 ; the cancellation plate 7 then centralises the pins. The plate 9 is pulled to the right by the latch when the lock is again closed, and the spring 36 causes the plate 7 to move to the right and return the member 22 to the central position through the action of projections 29, 30 on the cam surfaces 31, 32. To prevent setting of the push rods by feeling, the pins 3 may be loosely fitted in the push rods 2, and guided at each end between the plates 4 and 8, and further, those parts of the push rods which project from the casing may be reduced in diameter to avoid showing wear marks that might reveal the correct setting. In a modified construction, the plates 4 ... 8 are curved to the form of concentric circles, and move in part-circular guide-ways around their common centre.