Pilferage-prevention system

Claim 1

In a pilferage-prevention system, the combination comprising a building, an exit door in said building, a passageway in said building communicating with said exit door, an electrically operated lock associated with the exit door for locking the same, a radiation receiver located to receive radiation from within said passageway, an electric power source, electrical-connection means between said source and said lock, a first switch means in said connection means to operate said lock, relay means connected between said receiver and switch means for closing the first switch means to lock said lock responsive to reception of radiation by said receiver, radiation-producing means detachably carried by said articles in said building for transmitting radiation to said receiver upon movement into and through said passageway, electric closing means for closing said exit door, double-throw switch means in the electrical connection means between said first switch means and each of said closing means and the lock of said exit door, and operating means associated with said double-throw switch means to successively close the latter to said closing means responsive to operation of said first switch means for closing the exit door and close the double-throw switch means to the lock of said exit door for locking the latter.