Patent GB-204416-A (GB)
Title: Improvements in or relating to permutation locks
IPC: E05B37/00
Filed: 1922-07-03
Abstract: 204,416. McCabe, F. A. July 3, 1922. Locks, permutation.-In a permutation lock of the type in which a sliding bolt is blocked by a second sliding piece, the movement of the blocking piece is governed by a series of notched discs coacting with projections in the operating rod for the blocking piece, and the single-knob " means for setting these discs is disconnected from them before the blocking means and bolt are operated. The notched discs are duplex for changing the combination and the projections on the operating shank are also adjustable. Fig. 2 shows the lock with the cover removed. The bolt 1 has a reduced tail 1<b> wth serrated inclined part 1<c> coacting with a blocking piece 4, which slides at right angles to the bolt and has a serrated part 4<a> and stem 4b guided in the strap 3. The piece 4 is operated from the rod 13 by levers 15, 14, and the rod 13 is pivoted at 13<a> to a lever 12 pivoted to the casing at 12<a> and connected to the bolt-operating lever 8 by a link 11. The lever 8 is pivoted at 6 and is operated by the handle 7 to withdraw the blocking piece 4 and operate the bolt 1. The rod 13 has mounted concentrically upon it four cylinders 20b of diminishing lengths, each having a collar 20<a> provided with a lug 20 at one end, and a flange 20e and a feather 20f at the other. The lugs 20 co-operate with the notched discs 18 and the flanges 20<e>, and feathers enable a disc 20<c> to be fitted to each cylinder, Fig. 3, for enabling the positions of the lugs 20 to be altered for changing the combination, the discs 20<c> being held in position by a common spring-bar 21 engaging teeth in their periphery. The discs 18 comprise an outer member 18<a> and an adjustable inner member 18<e>, provided with a notch 18<h> to allow the projections 20 to pass through when properly set. The discs 18<a> have pins 18<n> and grooves 18<b> with slightly movable stops 18m for setting, which is effected by to and fro rotations of a dial 29 on the spindle 28 causing corresponding rotations of the disc 22<a> by the gearing 27, 26, 24, 23, 22, the toothed disc 22<a> having a pin engaging the groove 18b of the first disc 18. When the discs 18 have been set by the dial 29 to the position in which the projections 20 on the rod can pass freely through the notches 18<h>, unlocking can be effected by rotating the handle 7. The levers are so proportioned that when the handle 7 is moved, the bolt 1 and rod 13 are moved through a less distance than the rod 23 attached to the disc 22a, so that the disc 22<a> is slid along the toothed cylinder 22 and disconnected from the permutation discs 18 before the bolt 1 is appreciably withdrawn, thereby preventing picking by feeling. The relative lengths of the arms of the bell crank lever 14 however, and the space initially between the faces 1<c> and 4<a>, enable the blocking piece 4 to be moved into or from the path of the bolt simultaneously with the operation of the bolt, for locking or unlocking, by the handle 7. The member 13 has a spring element for taking up strain due to further rotation of the handle 7 when the piece 4 is fully withdrawn. The lugs 20 and flanges 18<h> normally have a clearance as shown in Fig. 3 so that on an attempt being made to move the bolt by the handle 7 while turning the disc controlling the notched locking discs, the bolt can move back until it engages the edge 4<a>, and the lugs 20 move into engagement with the flanges 18<h> and the disc 22<a> moves out of contact with the locking discs, further preventing picking by feeling.