Patent GB-614387-A (GB)
Title: Cylinder lock
IPC: E05B27/08
Filed: 1944-01-27
Abstract: 614,387. Locks. SPIKU-TRUST. Jan. 27, 1944, No. 1564. Convention date, Jan. 30, 1943. [Class 44] The invention relates to cylinder locks of the kind described in Specifications 391,482 and 438,513, in which a key with pins of different lengths which normally can only be inserted and withdrawn in one position, but having a position in which the key can be withdrawn for the purpose of changing the setting of the pins of the key. According to the invention, two positions in which the key is normally inserted and withdrawn are provided, with a neutral position for changing the setting, and the keys ordinarily used cannot be withdrawn even in the neutral position. For this purpose, at least one locking slide capable of being released or disconnected is provided to prevent unintentional withdrawal of the key in the neutral position, and the bit of the master key has a section different from that of the standard keys, so that, with the grooved member released, the master key, but not the standard keys, may be withdrawn or inserted with the lock in neutral position. In the form described, a housing 1 is formed with six dovetail-shaped grooves 2 in which slide members 3 have circumferential grooves on their inner surfaces. A rotatable member 4, also located in the housing, is formed with dovetail grooves 5, to each of which corresponds a longitudinal bore 6 and a slot 7, and in which are housed U- shaped slides each comprising a dovetailshaped part 8, located in the groove 5, a bridge part 9, working in the slot 7 and a bolt part 10 sliding in the bore 6. These slides are normally urged by springs 11 towards the front of the lock. Noses 12 on the slides make contact with the ends of the members 3 when member 4 is in the intermediate angular position of Fig. 1; in any other position longitudinal movement of the members 3 is prevented by engagement of the grooves thereon in corresponding grooves 75 on the member 4. Insertion of the key when the lock is in the intermediate position shifts the slides 8 and the members 3 individually to the extent determined by the lengths of the pegs 14, Fig. 8, of the key; subsequent turning of the key and of the member 4 engages the grooves of the latter with those of the members 3 and so locks the latter axially. The noses 12 of the slides being now free from the members 3, the slides are free to move axially, and are forced back by the springs 11 if the key is removed. The member 4 can then only be turned back by a key of the same peg combination as that used to displace the slides. In opening or closing the lock the key is in one of the positions shown in Figs. 3 and 5; to unlock, the key is inserted in the position of Fig. 5, and turned anti-clockwise to the position of Fig. 3 so that the members 3 now engage with the other grooves 15, Fig. 1, of the member 4. Between these two positions, i.e. in the intermediate position of Figs. 1 and 2, the lock can be set to another combination of key pegs by withdrawal of one key and insertion of another, and the first key would no longer fit. To prevent such withdrawal, the keys are provided with grooves 16, Figs. 9 and 11, engaging locking members 17, 18, Figs. 2, 3. The lock plates 17 are fixed to the housing 1 by pivots 19, Figs. 2 and 3, and engage in a groove in the member 4, cut-out parts 21 registering with the key slot in the open lock position. The locking slides 18 also engage in the groove in the member 4, but are normally pressed against the locking plates 17 by projections 23 on the cover disc 24 by means of a spring 25. Cut-outs 26 in the slides 18 enable the key to be withdrawn in the looked position.