Vibration responsive door alarm

• US 4,282,518 A
• Filed: 07/09/1979
• Issued: 08/04/1981
• Est. Priority Date: 07/09/1979
• Status: Expired due to Term

• Current Assignee: Edgar L. Bonner
• Original Assignee: Edgar L. Bonner
• Inventors: Bonner, Edgar L.
• Primary Examiner(s): Swann, III, Glen R.
• Application Number:
  US06/056,132
• Time in Patent Office: 757 Days
• Field of Search: 340/546, 340/566, 340/527, 340/545, 340/65, 340/309.1, 340/571, 307/293, 307/252 A, 307/252 R
• US Class Current: 340/566
• CPC Class Codes: G08B 13/08 by opening, e.g. of door, of window, of drawer, of shutter, of curtain, of blind
• CPC Class Codes: G08B 13/1654 using passive vibration detection systems

Abstract

An alarm device responsive to vibration includes a unitary housing in which is disposed an SCR for connecting an alarm signal to an associated source of power, the gate of the SCR being connected to a pendulum and ring assembly with the pendulum being normally suspended within the ring out of engagement therewith but which moves into engagement with the ring when the housing is subjected to vibration to apply power to the SCR gate so that the SCR conducts to actuate the alarm signal for indicating the application of a vibration to the housing or a supporting structure on which the housing is mounted. The alarm device may also include timing circuitry which deactivates the SCR after a predetermined period of time.

Claims

1. An alarm device comprising, in combination, a housing, means for attaching said housing to a supporting structure, an audible alarm in said housing, a battery in said housing, an SCR having a gate for connecting said audible alarm to said battery, vibration responsive switch means connected to said SCR gate for activating said SCR when said housing is subjected to vibration to connect said signaling means to said associated source of power for indication by said signaling means of the vibration on said housing, said vibration responsive switch means comprising a pendulum of tapered configuration and a ring assembly, means for supporting said pendulum in said housing within said ring for swinging movement from an inoperative position in spaced-apart relationship with said ring in the absence of vibration on said housing and an operative position in contact making engagement with said ring in the presence of vibration on said housing for activating said SCR, said pendulum supporting means including means for adjusting the axial position of said pendulum within said ring to thereby predetermine the magnitude of the vibration for moving said pendulum into said operative position, said adjusting means including a retainer on said housing, a slide member mounted on said retainer for movement into a selected vertical position, a strand of predetermined length connected between said slide member and said pendulum to provide a constant frequency of sensitivity, said slide member being movable into said selected vertical position for adjusting the sensitivity of said vibration responsive switch means at said constant frequency of sensitively, said SCR being connected in series with said audible alarm, the positive terminal of said battery being connected to one side of said audible alarm and the negative terminal of said battery being connected to the cathode of said SCR, means for connecting said ring to the gate of said SCR and means for connecting said pendulum to one side of said audible alarm.

2. An alarm device in accordance with claim 1 wherein said means for connecting said ring to said SCR gate includes timing means connected to said SCR for deactivating said SCR after a predetermined period of time.

3. An alarm device in accordance with claim 2 wherein said timing means comprises a capacitor having one side connected to the negative terminal of said battery, a further SCR having a gate for connecting said capacitor to said battery to fully charge said capacitor upon movement of said pendulum into said operative position, said further SCR having a cathode connected to the other side of said capacitor and an anode connected to said positive terminal of said battery, and means for connecting said capacitor other side to the gate of said SCR connected to said audible alarm to activate said SCR for a predetermined period of time corresponding to the period of discharge of said fully charged capacitor.