GB985092A - Improvements in and relating to locks - Google Patents

Abstract

985,092. Locks. MOSLER SAFE CO. March 20, 1961 [April 27, 1960], No. 10155/61. Heading E2A. A combination lock of the type having a dial 2 adapted to rotate a set of circular tumblers 78-81 each of which has a gate 93 and is so connected to the other tumblers by dogs and lost-motion couplings that the gates can be aligned by rotating the dial to form a slot to receive a fence 58 connected to the lock bolt 37 by arm 56 and stud 55, so that upon further rotation of the dial the bolt is withdrawn, is characterized in that the bolt 37 has a cutout 51 (Fig. 5) aligned with which, in the locked position, is a plunger 45 normally held in the position shown by a projection 107 supported by a plug 105 of low melting point material fixed in the cover plate 10 of the lock. If the lock is heated or the cover plate removed when the lock is closed, the plunger 45 engages the bolt 37 to hold it in the closed position. A set of false tumblers 25-27 are provided, one of which is fixed to a driver 17 to rotate with the true tumblers and the others of which are loosely mounted on the driver. Each false tumbler has a series of notches 36 similar to the gates in the true tumblers. The true tumblers which are made of nylon have a series of thin webs 92 spaced about their circumference which are identical in size to the gates whereby if the true tumblers show up on an X-ray photograph the gates will not be distinguishable from the webs. A disc 24 is fixed to the driver 17 by a stud and socket connection arranged to have a small amount of play so that as the driver is turned the connection makes a click similar to that which is produced as the tumblers are turned. A nylon friction plug 75 is spring pressed against the driver to further reduce the sounds of the members turning. Vibrations in the arm 56 are damped by a tension spring 60 which holds the dog 57 (connected to the fence 58) in contact with the shoulder 20 and includes a length of a flexible cylindrical material 63 within the coils of the spring. The stud 55 (Fig. 1) engages in a slot 101 supported by the cover plate 10 and is arranged so that the head of the stud engages the sides of the slot to retain the cover plate in position except when the bolt 37 is fully extended when the head of the bolt is aligned with a widening of the slot and so allows the cover plate to be removed. By resetting the engagement of a series of teeth 96 on the tumbler hub with those on the gate ring, different combinations may be formed.