Patent GB-615716-A (GB)
Title: Improvements in combination locks
IPC: E05B37/12
Filed: 1945-05-05
Abstract: 615,716. Permutation locks. PORCHE, J. H. May 5, 1945, No. 11481. [A Specification was laid open to inspection under Sect. 91 of the Acts, May 5, 1945.] [Class 44] A permutation lock is operated by a single rotatable control member with a gear-wheel coaxial therewith and capable of being coupled thereto which, according to its direction of rotation drives one or other of two cam wheels, each of which has a recess into which pins on a sliding plate controlling the lock bolt &c. can engage when the cam wheels are set to opening position ; each cam wheel has a series of recesses, one of which is deeper than the others, in which engages a spring plunger, and the member carrying the plunger is rotatable about the axis of the cam wheel to vary the setting of the mechanism. As shown in Figs. 1 and 2, the lock comprises a pair of idle wheels 1, 2, carrying pawls 3, 4, which actuate ratchet wheels 5, 6 secured to cam wheels 7, 8. The cams co-operate with studs 9, 10 on a sliding plate 11, the end 12 of which makes contact at one end of its travel with a hooked member 13 arranged to lock the spindle of a door lock. The cams, ratchets and wheels rotate on pins 14, 15 secured to a plate 16. Also carried by the pins 14, 15 are hand levers 17, 18, having housings carrying spring-pressed balls 22, each of which projects through one of a ring of holes in the plate 16 to engage in a series of recesses 19 and one hole 20 formed in the cam wheels 7, 8. The wheels 1, 2 are rotated by means of a central wheel 27 carrying pins 28 which engage in holes in a disc 32, the number of holes being the same as that of the recesses 19, plus hole 20. The disc 32 is mounted on a shaft 30 rotating in a bush 29, and by means of a screw 34 the shaft 30 may be shifted axially against a spring 37 to disengage the disc from the pins 28. The sliding plate 11 is pressed upwardly by a spring 39 so that the studs 9, 10 are pressed against the cam wheels 7, 8. To set for a given combination, the mechanism is brought to the unlocking position of Figs. 1 and 2, in which the holes 20 in the cam wheels 7, 8 are at thellowest point, and the levers 17, 18 are rotated in turn to selected positions after lifting the ball housings by pulling out the knobs 26. Knob 31 is then rotated, and one or other of the cams is rotated by the wheel 27, causing locking. To unlock, the knob 31 is rotated in one direction up to the engagement of the movable stop into the hole 20, which can be felt by the higher resistance. Thereafter the same operation is repeated in the reverse sense, and then the digits of the selected combination are counted out, by reference to the clicks made as the plunger engages the recesses 19, first in one sense and then in the other. Fig. 5 shows a mechanism operating with a three digit combination. The main construction is similar to that of the two-digit form, but the stem 30 of the knob 31 carries a grooved disc 51 which, when the stem 30 is shifted axially,. operates a lever 54 which in turn shifts a slider comprising a stem 59 and a number of discs 63-66, passing through a slot in the sliding plate 11. One of the discs, e.g. disc 63, is smaller than the others, and when positioned in the plane of the plate, allows movement thereof. The stem 30 is yieldingly held in its axial positions by a spring ball engaging grooves 45 on the end of the stem.