GB1201622A - Improvements in push button combination locks - Google Patents

Abstract

1,201,622. Locks. A. C. SANOWSKIS. 30 Aug., 1967 [31 Aug., 1966], No. 39758/67. Heading E2A. A push button operated combination lock has a plurality of buttons 28, requiring the consecutive depression of a predetermined sequence of some or all of the buttons to effect the change of said lock from an initial locking condition to an unlocking condition and includes racks 114, 116 movable by said buttons and shiftable step by step in a first direction to unlocking condition to allow a spring biased bolt lath 96 to extend therethrough but only upon depression of the correct sequence of buttons and wherein depression of said buttons in other than the predetermined sequence serves to prevent the movement of the racks towards said unlocking condition and spring means both for withdrawing the spring biased bolt lath from the racks and for resetting the racks to the initial locking condition. The two racks 114, 116 are slidably mounted in a slot 52 of a body 24 which also supports the push buttons 28. Each push button can engage tines 118 of the racks by means of an arm 48 of a spring 44 and each spring 44 and its associated push button is biased to the inoperative position by a spring 72 which surrounds a guide post 70 on a cover plate 26. Some of the tines of the racks have surfaces 126 which are inclined in one direction, some have surfaces 128 which are inclined in the opposite direction and some have both surfaces inclined, when the predetermined buttons are consecutively depressed in the correct sequence each arm 48 engages one of the surfaces 126 of both racks so that the racks are moved together one step at a time. If an incorrect button is depressed or the chosen buttons are depressed in the wrong sequence the arm 48 of the incorrect button engages of one of the inclined surfaces 126, 128 of one rack only and hence the racks are moved relative to each other. Each rack has a notch 122 which notches are normally aligned and which remain aligned as long as the racks are moved step by step by the predetermined sequence of buttons and when the last button of the sequence is depressed the notches reach a position which allows the bolt tongue 98 on the bolt lath 96 to extend through the notches under the urge of the spring which biases a latch bolt head 18 coupled to the bolt lath 96 to a releasing position in which it is free of a recess in a door frame. The tongue 98 normally engages an imperforate portion of the nearest rack, and remains engaged with such portion or with the imperforate portion of the other rack if the racks are moved relative to each other by incorrect depression of one of the push buttons. The bolt lath 96 and the racks 114, 116 are restored to the locking condition by depression of a push button 58 which by folding a spring 136 causes the spring to engage a projection 16 of the bolt lath 96 to remove the tongue 98 from the notches. A spring 130 which engages a notch 66, 66' as the body 24 presses against the ends of the racks to return them to initial position. The spring member can have the form of a spring urged lever pivoting on the body and engaging the ends of the racks or a coil spring or resilient plug. The setting can be changed by adjusting the spring member. If the lock is supported in a vertical position on the door the force of gravity moves the racks into contact with the spring 130 when the bolt tongue is removed from the notches or from engaging a rack and consequently one spring only at the lower end is necessary.