GB417525A - Improved construction of lock - Google Patents

Abstract

417,525. Permutation locks. JOHNSON, C. W., 16, Sibthorp Street, Lincoln. April 7, 1933, No. 10448. [Class 44.] A permutation lock is applied to a door, such as the door of a motor road vehicle, to prevent the external handle from operating the latch until the lock mechanism is correctly set. The casing 10 has a wall 10<a> with a number of holes in which rest cylindrical studs 21 with conical heads 23 arranged above grooves 22. The heads 23 project through holes 15<c> in plates 15 which have reduced ends 15a, 15b resting in slots in the casing walls 13, 13<a>. A comb spring 18 attached to the side of the casing keeps the plates in the position shown in Fig. 8, with the ends 15<a> projecting from the casing. Each plate has a hole for the passage of the conical head 23 of its corresponding stud, but one or more of the holes is out of alignment with the remainder, so that one or more of the studs is locked against movement. The studs are fixed to a plate 20 which carries a hookshaped projection 24 normally engaged by the hook 25 secured to the spindle 26 of the external door handle 27. This engagement locks the handle 27 against movement. To release the handle, certain press buttons 31 are depressed to move the plates with displaced holes, so that each hole is concentric with its corresponding stud. The handle 27 can then be operated, and during the first part of its movement the engagement of the hooks 24, 25 causes the withdrawal of the heads 23 from the plates 15. The continued rotation of the handle operates the latch 33 so that the door can be opened. The handle 27 is returned to its normal position by a spring, and the hook 25 raises the plate 20 and the studs 21 to the locking position. The latch can always be operated by the internal handle 32.