GB1411825A - Vibration detector - Google Patents

Abstract

1411825 Vibration detectors GUARDIAN INDUSTRIES Inc 25 Sept 1973 [29 Sept 1972] 44843/73 Heading G1J [Also in Divisions G4 and H1] A vibration detector 10 for use in a burglar alarm system is mountable on a surface 12 the vibration of which is to be detected, and includes an inertia mass 14 movably mounted with respect to the surface 12, an amplifying linkage responsive to relative movement between the mass 14 and the surface 12 to amplify said movement, and indicator means responsive to the amplified movement to indicate when vibration of the surface 12 exceeds a predetermined intensity. A lever 16 having a fulcrum 18 carries the mass 14. An adjustable compression spring 19 acts on the lever 16 to press its free end 20 against an arm 23 of an amplifying lever 22 having a fulcrum 24. The notched end 26 of the lever 22 engages a tab 30 of a member 32 to latch the latter against pivotal movement in its pivots 48, 48'. The fulcra 18, 24, 48, 48 are fixed relative to the detector housing 50, which is secured to the surface 12 by adhesive, self-adhesive tape, or bolting. When vibration of the surface 12 relative to the inertia mass 14 reaches a predetermined intensity, the amplified movement of the end 26 of the lever 22 is sufficient to release the tap 30 so that the member 32 pivots through 90 degrees under the spring action of a phosphor-bronze strip 44. A flag 46 integral with the member 32 but outside the housing 50 indicates that the detector has been triggered, and a contact 84 on the strip 44 is moved out of contact with a contact 86 and into contact with a contact 88. The detector can be reset manually, using the flag 46. If the detector is removed from the surface 12, a feeler 70 on a lever 72, which feeler normally contacts the surface 12, moves so that an arm 76 of the lever 72 lifts the lever 22 to unlatch the member 32. The alarm circuit, Fig. 4, includes one or more detectors 10. With all detectors set, a battery 100 energizes the solenoid 112 to hold open the contact 114, 118 of an alarm circuit 120, 122. Triggering of any detector 10 by vibration, removal of the detector from the surface 12, cutting the line 108 or 110, or inadvertent shorting between the lines 108, 110, de-energizes the solenoid 112 to activate the alarm circuit.