Patent GB-218313-A (GB)
Title: Improvements in safety locks
IPC: E05B55/00
Filed: 1924-06-27
Abstract: 218,313. Bilde, T. E. D. June 27, 1923, [Convention date]. Locks, revolving-barrel; locks, preventing picking of; latches, sliding. - A follower-operated latch of the type described in Specifications 8881/92 and 11816/96 is retracted by inside and outside handles connected by a two-part hollow spindle which contains locking mechanism such that a key must be inserted into the spindle section associated with the outer handle for release of the latch by this handle. Fig. 2 shows the halves 9 and 10 of the hollow spindle associated with the outer and inner handles respectively. Slides 18 are housed within the outer half 9 and project into a piston 17 housed in the inner half 10. The piston has teeth 19 engaging teeth 20 on the spindle but normally kept apart by a spring 21. The inner handle carries a follower 6 which operates the latch bolt. The outer handle normally moves idly, a stud 11 engaging a slot 12 in the boss of the follower 6. The outer handle carries an arm 5 on which a spring acts to keep the stud 11 at the end of the slot 12. To operate the latch by means of the outside handle, the spindle parts 9 and 10 must be rigidly coupled. This is effected by inserting the key 24 into the keyhole 25, and thrusting, the sliders forward against their springs 22. At a certain point of the insertion of the key, the notches 26 of the sliders are opposite a lug 27 on a member 23 and the tension of the springs 22 is sufficient to move the piston 17 forward against its spring 21. A lug 28 on the piston rocks the member 23 about its part 29 as the piston moves forward to cause the teeth 19, 20 to engage, causing the lug 27 to enter the notches 26 in the slides and the lug 30 to leave the notch 31 in the spindle. Rotation of the outer handle now rotates the inner handle and causes the follower 6 to withdraw the latch. The Specification as open to inspection under Sect. 91 (3) (a) comprises also the form shown in Fig. 6 (Cancelled), wherein the slides are divided and the key 24 is inserted to align the breaks so that the member 37 can be turned to cause its teeth T to engage those T<1> of the member 38 under the action of the spring 39, and the form shown, Fig. 9 (Cancelled) in which the three conditions of the lock are possible namely, (a) that in which the lock can only be operated by the inside handle, (b) that in which the latch can be operated by both the outside and inside handles, and (c) that in which the latch can be operated by the outside handle only. A member 42 with teeth 43 is situated between the piston 17 and the end of the inner handle spindle. In the position shown, the distance between the teeth 41 on the piston and 43 on the member is too great for their engagement when the key is inserted into the key hole 25 and pushed home so that opening by the inside handle is alone possible. If the tool 45 is inserted from the inside and pushed forward till shorter legs 47 on the member 42 clear shoulders and then rotated, the distance between the teeth is such that the key on insertion, can cause the teeth 41, 43' to engage so that opening by the outside handle with the aid of a key is possible. If the tool 45 is used to push the member 42 fully home and is rotated so that longer legs 48 on it retain it in the position, the teeth 41, 43 are permanently engaged and opening by both inside and outside handle without use of the key is possible. The sliders, as shown in Fig. 2, have bevelled edges 32 to cause a picking implement to slide off them into recesses 33. This subject-matter does not appear in the Specification as accepted.