Alarm apparatus for detecting disturbance or other change of condition

• US 4,253,095 A
• Filed: 06/07/1978
• Issued: 02/24/1981
• Est. Priority Date: 06/07/1978
• Status: Expired due to Term

• Current Assignee: Modern Technologies Corp. (BAE Systems Plc)
• Original Assignee: Freund Precision, Inc.
• Inventors: Schwarz, Ray P., Valentine, Daniel R.
• Primary Examiner(s): Swann, III, Glen R.
• Application Number:
  US05/913,472
• Time in Patent Office: 993 Days
• Field of Search: 340/689, 340/691, 340/384 E, 340/546, 340/571, 340/63, 310/321, 310/317, 200/43
• US Class Current: 340/691.8
• 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 13/1436 with motion detection
• CPC Class Codes: G08B 3/10 using electric transmission; using electromagnetic transmission

Abstract

A compact portable housing encloses a piezoelectric element which receives short pulses from a pulse generator circuit controlled by a ramping waveform generator circuit so that the element and the adjacent speaker portion of the housing produce a frequency modulated loud sweeping sound. The housing also encloses a detector switch for sensing a disturbance, and the sensitivity of the switch may be adjusted according to the position of the housing. The detector switch actuates a timer circuit which is armed or disarmed by moving a combination code switch having code wheels projecting from the housing.

Claims

1. Apparatus for producing a loud audible alarm is response to a distrubance, comprising a piezoelectric element, means for exciting said element, a motion detector switch for sensing a disturbance a pulse generator circuit for supplying short electrical pulses to said exciting means, a ramp waveform generator circuit connected to control the frequency of the electrical pulses of said pulse generator circuit to produce a sweeping sound from said element, a control circuit for actuating said pulse generator and waveform generator circuits in response to the sensing of a disturbance by said detector switch, a housing enclosing said piezoelectric element, exciting means, detector switch, pulse generator circuit, ramp waveform generator circuit and control circuit, a combination control switch including a plurality of rotary code wheels arranged in tandem relation and having portions projecting from said housing, means supporting said code wheels for independent rotation on parallel axes, a flexible contact element for each of said code wheels, a rotary actuator supported for rotation with each said code wheel, said actuators projecting axially from said code wheels and having means for flexing the corresponding said contact elements and for deactuating said control circuit in response to rotating all of said code wheels to corresponding predetermined code positions, and battery means within said housing for supplying power to said piezoelectric element.

2. Apparatus as defined in claim 1 including means for adjusting the circumferential position of said actuator relative to the corresponding said code wheel.

3. Apparatus for producing a loud audible alarm in response to a disturbance or other change of condition, comprising a piezoelectric element, detector means for sensing a disturbance, a pulse generator connected for supplying short electrical pulses to energize said piezoelectric element, a waveform generator connected to control said pulse generator for varying the frequency of the pulses supplied by said pulse generator to produce a frequency modulated sweeping sound from said element, a control circuit for actuating said waveform generator and pulse generator to produce varying frequency pulses in response to the sensing of a disturbance, a housing enclosing said piezoelectric element, said detector means, said pulse and waveform generators and said control circuit, said housing including a speaker portion having a cup-shaped wall portion defining a chamber adjacent said piezoelectric element, a plurality of peripherally spaced and generally coplanar openings within said wall portion, and wall means disposed around said wall portion and forming a surface spaced radially outwardly from said openings and opposing said openings.

4. Apparatus as defined in claim 3 wherein said wall means comprise a generally circular wall having circumferentially spaced gaps, and said openings comprise slots.

5. Apparatus as defined in claim 3 wherein said housing includes a front section and a rear section coupled together, said front housing section including said speaker portion, and said rear section enclosing said battery means for supplying power to said piezoelectric element.

6. Apparatus for producing a loud audible alarm in response to a disturbance, comprising a piezoelectric element, means for exciting said element, a motion detector switch for sensing a disturbance, a pulse generator circuit for supplying short electrical pulses to said exciting means, a ramp waveform generator circuit connected to control the frequency of the electrical pulses of said pulse generator circuit to produce a sweeping sound from said element, a control circuit for actuating said pulse generator and waveform generator circuits in response to the sensing of a disturbance by said detector switch, said control circuit including timing means for causing an enabling signal to be provided to said pulse generator and waveform generator circuits for a predetermined period of time after a single disturbance is sensed by said detector switch, a housing enclosing said piezoelectric element, exciting means, detector switch, pulse generator circuit, ramp waveform generator circuit and control circuit, said housing including a speaker portion having a cup-shaped wall portion defining a chamber adjacent said piezoelectric element, a plurality of peripherally spaced and generally coplanar openings within said wall portion, wall means spaced radially outwardly from said openings and opposing said openings, a combination control switch including a plurality of rotary code wheels having portions projecting from said housing, said control switch having means for deactuating said control circuit in response to rotating all of said code wheels to corresponding predetermined code positions, and battery means within said housing for supplying power to said piezoelectric element.