Power tool theft alarm

• US 4,151,521 A
• Filed: 09/15/1977
• Issued: 04/24/1979
• Est. Priority Date: 09/15/1977
• Status: Expired due to Term

• Current Assignee: John C. Wirth Jr
• Original Assignee: John C. Wirth Jr
• Inventors: Wirth, John C. Jr.
• Primary Examiner(s): Waring, Alvin H.
• Application Number:
  US05/833,809
• Time in Patent Office: 586 Days
• Field of Search: 340/253 B, 340/253 R, 340/256, 340/276, 340/280
• US Class Current: 340/568.3
• CPC Class Codes: G08B 13/1409 for removal detection of electrical appliances by detecting their physical disconnection from an electrical system, e.g. using a switch incorporated in the plug connector

Abstract

The internal impedance loads of a plurality of electrical appliances on display are directly connected in series through their power switches and power cords by a connector strip to form a detection circuit. Interruption of the detection circuit is sensed by a relay to activate a power operated alerting device. Continuity of the detection circuit is maintained by plugging all of the power cords into the connector strip and holding all of the power switches closed by removable binding tape or the like.

Claims

1. In combination with a plurality of electrical appliances, each enclosing an electrical load adapted to be connected to a power source through a power cord and a plug upon closing of a power switch for operation of the applicance, an anti-theft system for protecting the appliances disconnected from the power source, comprising:

means for holding the power switches closed, connector means engageable with the plugs for electrically connecting all of the electrical loads and the power switches in series, a power operated alerting device, and sensing means connected to the connector means for activating the alerting device in response to opening of any of the power switches or withdrawal of any of the plugs from engagement with the connector means.

2. The combination of claim 1 wherein said connector means comprises an elongated circuit strip mounting a plurality of receptacles receiving the plugs, and wiring means interconnecting the receptacles in series for establishing a detection circuit only through the power switches and the electrical loads of the appliances.

3. The combination of claim 2 wherein said electrical loads include electrical motors of power tool appliances.

4. The combination of claim 3 wherein the power switch holding means comprises adhesive tape holding the power switches in actuated positions.

5. The combination of claim 1 wherein the power switch holding means comprises adhesive tape holding the power switches in actuated positions.

6. The combination of claim 5 wherein said connector means comprises an elongated circuit strip mounting a plurality of receptacles receiving the plugs, and wiring means interconnecting the receptacles in series for establishing a detection circuit only through the power switches and the electrical loads of the appliances.

9. The combination of claim 1 wherein each of said electrical appliances includes a housing within which the electrical load is mounted and on which the power switch is mounted.

7. In combination with a plurality of electrical appliances, each having an internal impedance adapted to be connected to a power source through a power cord upon closing of a power switch for operation of the applicance, an anti-theft system for protecting the appliances disconnected from the power source, comprising:

means for releasably holding the appliance power switches closed, means detachably connected to the power cords for establishing a common series detection circuit through all of the closed power switches and the impedances of the applicances, and means responsive to interruption of said series detection circuit for producing an alarm signal.

8. The combination of claim 7 wherein said circuit establishing means includes an elongated circuit strip mounted on the displaying means, a plurality of connectors mounted on the strip to which the power cords are detachably coupled, and conductor means interconnecting the connectors in series for establishing said series detection circuit.

10. The combination of claim 8 wherein each of said appliances includes a housing enclosing the impedance and on which the power switch is mounted, said holding means comprising removable tape anchored to the housing and holding the power switch depressed.