THEFT ALARM OPERABLE BY VIBRATION

• US 3,721,956 A
• Filed: 02/08/1971
• Issued: 03/20/1973
• Est. Priority Date: 02/08/1971
• Status: Expired due to Term

• Current Assignee: Jack C. Dawson, Victoria Hamann
• Original Assignee: Jack C. Dawson, Victoria Hamann
• Inventors: Hamann, Victoria, Dawson, Jack C.
• Primary Examiner(s): Caldwell, John W.
• Assistant Examiner(s): Swann, III, Glen R.
• Application Number:
  US05/113,409
• Time in Patent Office: 771 Days
• Field of Search: 340/65,261 200/61.52,DIG.8,61.49
• US Class Current: 340/429
• CPC Class Codes: B60R 25/1007 comprising associated circuitry
• CPC Class Codes: B62H 5/20 indicating unauthorised use, e.g. acting on signalling devices alarm locks in general E05B45/00, e.g. alarm cable or chain lock E05B45/005

Abstract

An alarm is attached to a device such as a bicycle and operates when the device is moved. The alarm is controlled by a key switch which is turned on when the device is left unattended and must be turned off to de-energize the alarm. Within a casing is a vibration switch consisting of a weight on a flexible wire contained within a tube. Vibration and/or displacement from rest position causes the weight to establish momentary electric contact with the tube. The electric circuit contains a latching element such as a silicon controlled rectifier, the gate of which is connected to the vibration switch. With the key switch on, moving the device causes the weight to contact the tube, latching the rectifier on, and causing the buzzer to sound until the key switch is turned off.

Claims

1. An alarm responsive to vibration comprising a casing having means for attachment to a device to be guarded and containing the other components of said alarm, said components comprising a keyoperated switch having a first and second switch terminal, a battery having a first battery terminal connected to said first switch terminal and a second battery terminal, a latching silicon controlled rectifier having a cathode, an anode and a gate electrode, a buzzer having a coil, said coil connected between said second switch terminal and said anode, a first resistor across said coil, said caThode connected to said second battery terminal, a second switch comprising a conductive tube and a straight flexible conductive wire, means mounting said wire axially of said tube, a conductive weight on said wire normally centered within said tube when said device is at rest, a nonconductive washer having a central aperture in one end of said tube, said wire fixed in said aperture, said weight vibrating to establish electric contact with said tube when said device is moved, said flexible wire connected to said second switch terminal, a second resistor connected in series with said tube and said electrode gate, a third resistor connected to said gate and said second battery terminal, said third resistor being substantially less than the resistance of said second resistor, said rectifier being energized when said weight contacts said tube by vibration of said device to conduct the current through said coil from said battery continuing to flow until said key operated switch is opened.