Patent GB-738853-A (GB)
Title: Improvements in or relating to key-operated locks
IPC: E05B47/00
Filed: 1953-02-13
Abstract: 738,853. Magnetic locks. CALLOW, D. M., and BEARN, J. Aug. 4, 1953 [Feb. 13, 1953], No. 4126/53. Class 44. In a lock operable by a magnetic key, the lock is provided with one or more armature elements responsive to the magnetic influence of the appropriate key and serving by reason of the magnetic response as a thrust-transmitting device through which movement initiated by the turning of the key, is imparted to a bolt. In the arrangement shown, in which a lock body is built up of seven plates consisting of two sets of plates 1, 2 and 3, one on each side of a divider plate 4, gaps 5 formed in the plates 2 and 3 form chambers on each side of the plate 4 which house a pair of discs of a non-magnetic substance. A key slot 7 is provided in each of the plates 2, 3 and 4 and in the discs for engagement by a key having magnetic bits. A bolt 9, which is hollow and accommodates a spring-loaded thrust piece 12, is locked in its retracted and projected positions by a pair of locking levers 10 and maintains the discs in seating engagement with the lower edge 17 of each gap 5, gap edge portions 18 being set back to leave a clearance between them and the discs. A cylindrical armature element 20 is located in either of two recesses 19 clear of the peripheries of the discs. Recesses 21 formed in the discs receive part of the armature element when the latter is attracted by the key bits, the projecting part of the element 20 moving in the clearance between the discs and edge portions 18 when the discs are turned by the key, a slot 22 in the plate 4 permitting travel of the element 20 from one slot 19 to the other. A recess 23 in the bolt 9 is engaged by the projecting part of the element 20, the lever 10 being lifted by the element 20, prior to the element effecting the shooting of the bolt by entering a recess 24 in the piece 12 against the spring 14. The discs are held in normal position after complete rotation and withdrawal of the key, by a spring 21a cooperating with the recesses 21. The key bits are magnetic or magnetically responsive. In a modification, Fig. 6 (not shown), the key bits may be shaped to correspond to wards on the plates 1 and 4. In the arrangement according to Figs 8 and 9 (not shown) the key is provided with one fixed and one movable bit, the bits being normally urged into contact to preserve their magnetism. The bits are separated upon insertion of the key, by wards formed on the plate 4 and corresponding grooves on the keybit which allow passage of the bit through the plate. In a modification, the bits may be chamfered or the plate bevelled off to permit separation of the bits as the key is turned. In a further arrangement, Figs. 10 to 12 (not shown) the plate 4 is provided with a concentrically disposed nib having end portions projecting into a V-shaped gap in the plate where the key is inserted, the projections co-operating with a notch formed in the forward edge of the bit. In the arrangement according to Fig. 13 (not shown) the key comprises a centre fixed bit and slidable bits disposed one on each side thereof and provided with notches as in the Fig. 11 arrangement, for co-operation with divider plates of the Fig. 10 arrangement.