GB635316A - An improved safety appliance for use with door locks - Google Patents

Abstract

635,316. Latch and knob guards. DAVIS, L. A. W. Nov. 28, 1947, No. 31535. [Class 44] A guard for use with door locks comprises a movable cover member 1 associated with a fixed plate 2 adapted when the door is closed to encase the operating knob 4 of the lock 3 and when the door is opened to clear itself from the lock, automatically, under spring influence. The movable cover 1 forms three sides of an essentially rectangular box like casing the remaining sides of which constitute the fixed plate 2. The two members are hingedly connected along an edge 5 by knuckles 6 provided on members, engaging a spindle 4. A spring 8 is mounted upon a spindle 7 with its ends 9 soldered to the movable cover 1, and the base plate 2, respectively to urge the cover 1 away from the plate. In the end flange 15 of the movable cover 1 an aperture 17 is made of corresponding dimensions to those of the lock bolt aperture 18. To guard the knob 4 the movable cover 1 is pressed downwardly, the bolt 19 engaging aperture 17 to lock the cover 1 when the door is closed. When the lock bolt 19 is retracted from the outside of the door by a key and the door opened, the cover is freed from the bolt and moves upwardly under the action of its spring 8 to expose the knob 4. In a modification the cover is hinged about its lower edge so that on release it rotates downwardly. A further modification is described in which the cover is spring pressed to move in a vertical direction on guides or rails.