Patent GB-303480-A (GB)
Title: A safety lock
IPC: E05B37/00
Filed: 1929-01-01
Abstract: 303,480. Maire, A., and Beguelin, A. Jan. 4, 1928, [Convention date]. Latches, swinging; locks, permutation. - A rotatable latch member 16 operable by a knob or handle 5 is normally uncoupled from the handle spindle 6 so as to be unaffected by movements thereof. To effect operation of the latch member 16 coupling between the latch and spindle is effected by giving the spindle a number of alternate rotations in opposite directions, the number and extents of the movements being predetermined and known only to the initiated. The interior wall of the cylindrical casing 3 has a number of equally-spaced notches 9 (six shown) which are momentarily engaged by the end of a spring- pressed plunger 8 housed in a disc 7 carried and operated by the spindle 6. The momentary engagements can be felt and counted by the operator, in order to control the correct movements of the knob and spindle, the operation requiring a predetermined sequence of clicks in each direction. Disc 7 houses a spring-biassed sliding member 10 having a pin 12 near one end projecting through a slot in the front face of the disc. The member 10 is normally held by its spring 13 with its pin 12 near the periphery of the disc, Fig. 5, and its other end 10<a> within the disc. Pin 12 is adapted to engage in and be guided by channels formed by a series of concentrically disposed fixed members 18, Fig. 7 carried by the top 4 of the casing and each having a flexible end 19 normally in contact with the adjacent outer member. Each end 19 yields to allow passage of the pin 12 in one direction, but directs the pin, when returning in the opposite direction, into the next inner channel. Proper operation of the knob therefore moves pin 12 by a zig-zag path towards the centre of disc 7 with corresponding sliding movement of member 10 which moves its end 10<a> radially outwards. Latch-member 16 is loose and has a recess 17 which allows free passage of the projected end 10<a> until it has been moved outwards sufficiently far to clear the recess and engage the latch member, which can then be rotated to the unlocking position by rotation of spindle 6. In operation, the knob is first brought to a predetermined initial position as indicated by an index 20 on the knob 5, in which position the end 14 of member 10 is in proximity to an inwardly projecting fixed member 15 which serves to move member 10 to cause the pin 12 to enter the outermost channel on rotation of the pawl 5 in the right direction. With insufficient rotation in any direction, pin 12 fails to pass the corresponding flexible end 19 so that inward travel of pin 12 is not effected or completed, whilst too great a movement causes the pin to clear the end of the member 18, whereupon member 10 is returned by its spring to its original outermost position. The Specification as open to inspection under Sect. 91 (3) (a) described the invention in the form illustrated in Figs. 1 to 5 (Cancelled). In this form eight notches 9 are shown and the knob 5 has a corresponding member of peripheral recesses and a concealed mark 20. The member 10 has two pins 11, 12, projecting respectively through slots in the front and back faces of disc 7. Pin 12 co-operates in the way described above with guides 18, 19 carried by the bottom 2 of the casing, and pin 11 engages and operates a pivoted catch 16 of the form shown in Figs. 1, 2, (Cancelled). This subject-matter does not appear in the Specification as accepted.