GB299211A - Improvements in locks - Google Patents

Abstract

299,211. Pepper, L. Nov. 25, 1927. Locks, revolving-barrel; wards for; preventing picking of.-Unauthorized opening of radial pintumbler locks by a, tapping pick-lock is prevented by supplementary pin-tumblers 18 at an angle to and on both sides of the usual tumblers 12. Further security may be given by spring-plungers 19 at right-angles to one or more of the supplementary tumblers 18 so that when the barrel 14 is moved to bring these tumblers into line with those 13 in the barrel, the descent, of the tumblers enables the plungers 19 to snap into recesses and lock the tumblers against retraction. This prevents further rotation of the barrel for unlocking and retains the barrel in the partly turned position, indicating tampering. The correct key holds the pins 13 with their upper surfaces flush with the periphery of the barrel and so prevents the supplementary tumblers from coming into action. Further security may be ensured by providing wards 5 in recesses 6 in the barrel, necessitating corresponding cutting of the correct key.