Combination locks with electro-optical silent alarm system

In a combination lock having a lock case provided with a tumbler post, a rotatable combination lock dial positioned for manual manipulation to dial the lock combination and having spindle means driven thereby extending through the tumbler post, a lock mechanism in said case having components including a plurality of rotatable members to be rotatably positioned responsive to rotation of said dial comprising a tumbler wheel stack formed of a plurality of peripherally gated tumbler wheels loosely journaled on said tumbler post for rotation about its axis and a peripherally gated rotatable driving cam driven from the dial, coupling means intercoupling the driving cam and tumbler wheels for adjusting the angular positions of the tumbler wheels responsive to dial rotation, and a fence lever pivotally connected to a bolt for shifting the bolt between locked and unlocked positions and having a fence insertable into the peripheral gates of the tumbler wheels when they are properly aligned following dialing of the proper lock combination;

• the improvement comprising electro-optical light sensing and electrical signalling means for producing sensible indications at a remote monitoring station signifying movement of components of the combination lock mechanism comprising an optically distinctive marking on a component of the lock mechanism which moves during manipulation of the lock including at least one of said rotatable members, said marking having optically distinctive reflectivity properties from remaining parts of such component which occupy any of the path of movement traversed by the optically distinctive marking during movement of its associated component, optical sensor means including a light source for directing light onto the path traversed by said optically distinctive marking during movement thereof responsive to attempted opening manipulation of the lock and photosensor means positioned to receive light from said light source reflected from said optically distinctive marking at predetermined positions thereof for generating movement detection electrical signal signifying movement of said optically distinctive marking, electrical signal amplifying means for receiving said signal and producing an amplified output, and electrical circuit means including alarm signal producing means activated by said amplified signals to produce a sensible alarm signal at a remote monitoring station signifying movement of said optically distinctive marking.