GB534096A - Improvements in means for sealing door and like fastenings - Google Patents

Abstract

534,096. Door latches; seal fastenings. NEWMAN & SONS, Ltd., W., and SHEAD, H. C. Dec. 7, 1939, No. 31666. [Class 44] To prevent operation of the knob of a door latch, except in emergency, a cylindrical casing 21 secured to or integral with the latch casing 1, 2 surrounds the knob 17 with sufficient clearance to allow insertion of the hand, the outer end of the casing being closed by a plate 23 of glass, celluloid, paper or other disruptable material. The device is particularly for use to prevent or discourage the use of public air-raid shelters by unauthorized persons other than when an air-raid warning has been given, but allowing access in emergency by breaking the plate 23. The plate, if of glass, may carry a disc 24 bearing instructions for operation. Plate 23 is retained by the rim 25 of a frame 22 with pins 26 which slide into slots 27 in the casing 21 and are retained between extensions 30 and shoulders 31 of pivoted gravity catches 28. Alternatively, blade spring catches within casing 21 may project through apertures therein into engagement with recesses in frame 22. In either case the catches can only be released when the plate 23 has been broken, the arrangement allowing replacement with a new plate. The knob has a bearing portion 18 and externally square part 16 the end of which is riveted to a retaining plate 20. Part 16 fits into a two-armed follower 15 engaging projections 14 on the bifurcated bolt tail, and has a square aperture receiving the spindle 19 of an inside handle, not shown. The bolt is shot by a spring 4 bearing against one of two projections 5. The bolt may be retracted by an authorized person by means of a key inserted through a keyhole 9, the end of the stem passing through a slot 12 in the bolt into engagement with a bearing aperture 11, the bit of the key, when rotated, engaging one or other of two pins 10 carried by the bolt. The application to a mortise latch is described, the sealing chamber being separate from the latch casing, but screwing thereon when the latter has been fixed in place. The knob casing may contain a low-voltage lamp.