Article removal and pilferage detection system and apparatus

• US 3,972,039 A
• Filed: 03/14/1974
• Issued: 07/27/1976
• Est. Priority Date: 03/14/1974
• Status: Expired due to Term

• Current Assignee: Steven Grant Marshall
• Original Assignee: Steven Grant Marshall
• Inventors: Marshall, Steven Grant
• Primary Examiner(s): Caldwell, John W.
• Assistant Examiner(s): Wannisky, William M.
• Application Number:
  US05/451,049
• Time in Patent Office: 866 Days
• Field of Search: 340/280, 340/256, 340/420, 340/409, 340/253 R, 339/36, 339/37, 339/113 R, 339/113 B, 200/61.58 R
• US Class Current: 340/508
• CPC Class Codes: G08B 13/1454 Circuit arrangements thereof

Abstract

A three-wire alarm system is disclosed which features a plurality of plug-in strips each carrying a plurality of three-connector receptacles. These strips may be interconnected one to the next and to a battery-powered alarm box by identical jumper cables with three-pinned plugs. Other cables with identical plugs are fastened to valuable items which a merchant desires to display. When these items are placed on display, they are plugged into a nearby plug-in strip. The items may be plugged in without setting off the alarm; but removing any plug or cutting, shorting, or breaking the cables produces an alarm that can be turned off only with a key.

The three-contact receptacles of the invention contain a spring that (1) serves to interconnect two of contacts when the receptacle is not in use, (2) contacts the pin mating with the third contact when a plug is inserted, and (3) is dragged by that pin into contact with one of the other contacts when the plug is withdrawn thereby causing an alarm.

Claims

1. An alarm system to respond to the removal of a treasure from its assigned place, comprising:

a. an indicator subsystem containing a signal transmitter;

b. distributing means including at least three runs of wire extending from said subsystem to said treasure, and terminations of said runs such that a circuit of current is maintained from said subsystem outward along a first of said runs, and back to said subsystem along a second of said runs, and such that said third run extends with at least one of said other runs and is isolated therefrom to maintain a predetermined potential difference;

c. wherein said subsystem incudes detection circuit means so connected that cutting said circuit causes said transmitter to transmit an alarm, and so that making an electrical connection between said third run and said circuit even momentarily causes said transmitter to transmit an alarm;

d. said subsystem comprises a plug-in strip;

e. said strip comprising a plurality of identical connector receptacles;

f. each of said receptacles having three sockets for mating plug having three pins;

g. each of said receptacles having a spring to maintain the interconnection of two of said sockets until said pins are inserted, said spring being deflected by the outward motion of one of said pins upon withdrawal to make connection between one of said two and the third of said sockets;

h. wherein each of said two sockets is electrically connected to one and only one of said two sockets of another of said receptacles; and

i. wherein all of said third sockets are electrically interconnected each to all of the others.

2. A system as defined by claim 1

j. having a plurality of said strips, and

k. wherein one of said strips is connected to another of said strips by a jumper cable,

l. said jumper cable comprising a pair of said mating plugs, the pin of one of said plugs adapted to mate with one of said third sockets, being linked by a length of wire to the other pin of said pair adapted to mate with the third socket.

3. The system as defined by claim 1

j. wherein said subsystem comprises a sturdy protective box containing said signal transmitter and its operating source of energy,

k. said strip is connected to said box and said signal transmitter by a box connector receptacle in said box,

l. said box receptacle connector being of the same construction of said identical receptacles, and by a jumper cable, said jumper cable comprising a pair of said mating plugs, the pin of one of said plugs adapted to mate with one of said third sockets being interconnected to the pin of said other plug of said pair adapted to mate with another of said third sockets.