Patent GB-164704-A (GB)
Title: Improvements in or relating to safety devices for preventing the unauthorised operation of locking means
IPC: E05B37/04
Filed: 1920-10-16
Abstract: 164,704. Auto-Combinator Soc. Anon. June 14, 1920, [Convention date]. No Patent granted (Sealing fee not paid). Locks, permutation.-A bolt a is held in the locked position by a spring stop b engaging in a notch c and releasable only by the correct stepby-step operation of a permutation mechanism, which is so constructed that if an attempt is made to move the stop b, when an incorrect setting is made at any step the parts are restored to the original fully-locked position. The rings 19 can be set as desired, within a bush 30 when the mechanism is withdrawn from the lock casing. Spring pawls hold them in the set position, which is read through a gap in the bush 30 before the bush is re-inserted into the casing. The position of a slot in each ring is thus determined. The setting-knob 25 is connected to a flange 33 bearing a series of indications which, one at a time, are visible through a window 32. It also carries round with it a slotted shaft 7, within which are mounted a pair of levers, of which one, 15, having a nose 18, works in conjunction with the setting-rings, through the gaps 20 in which the nose 18 has to pass successively. The other lever 16 engages with grooves 22 cut in a sleeve 23, and so holds the shaft 7 against the action of a spring 27 as each step is correctly made. A worm 3, or a pawl device, operated by an external handle 14 moves the shaft 7 to the extent of the width of one ring each time it is operated. If the knob 25 is properly set for that step, the nose 18 passes through the gap 20 in the ring then in operation, and the nose 21 of the lever 16 rides up and snaps into the next groove 22 and retains the shaft 7 in the new position when at the end of the stroke a gap in the worm 3 disengages the worm from the rock-bar 2. Should the worm be operated to move the device 1 when the knob 25 is incorrectly set for that particular step, the nose 18 bears upon a flange of the ring 19 swinging the lever 15 inwardly, until it is retained by a spring catch 38, in which position the lever 16 is also withdrawn from engagement in its groove 22. Completion of the stroke of the handle 14 to release the member 1, thus allows the spring 27 to shoot out of the shaft 7 and a lever 40 meeting a stop 41 releases the catch 38, so that all parts are then restored to the initial fullylocked position. After correctly setting the knob, and operating the handle at each step, the part 1 is finally brought into a position where the finger f presses up the end e of the spring catch-rod, and frees the bolt a for operation in any convenient manner. The handle 14 is carried by a sleeve fitting over the rod 8, the end of the sleeve having a disc with a pawl. This pawl engages a spring pawl on a disc secured to the rod 8, when the handle is turned in one direction, revolving the worm 3, and leaving the rod 8 stationery when revolved in the other direction. The handle 14 may be connected to the rod 8 by a ratchet device, the sound of which masks the sound made by the movement of the levers 15 and 16, and the provision of mechanism independent of the operating knob for moving the shaft 7 prevents picking by feeling.