INERTIA TYPE SWITCH WITH COAXIAL CONDUCTIVE SPRINGS

• US 3,731,022 A
• Filed: 11/12/1971
• Issued: 05/01/1973
• Est. Priority Date: 11/12/1971
• Status: Expired due to Term

• Current Assignee: Peter J. Loftus
• Original Assignee: Peter J. Loftus
• Inventors: Loftus, Peter J.
• Primary Examiner(s): Scott, J. R.
• Application Number:
  US05/198,219
• Time in Patent Office: 536 Days
• Field of Search: 200/61.48,61.49,61.50,61.51,61.52,61.53,61.74,61.78,166BA,166J,61.45R
• US Class Current: 200/61.49
• 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
• CPC Class Codes: H01H 35/144 operated by vibration

Abstract

A motion sensor for sensing shocks, vibrations or the like utilizing a pair of contacts mounted on vibratory supports so that when the supports vibrate the contacts close, completing an electrical circuit. The vibratory supports and the contacts are such that the quiescent deflections of the two supports in response to constant forces move the two contacts by the same amount to maintain a constant quiescent spacing between the contacts and hence a constant sensitivity of the device to shocks, vibrations or other irregular motions. The sensitivity is therefore constant for a wide range of different quiescent orientations of the device.

Claims

1. A motion sensor, comprising:

a supporting base;

a first spring system secured to said base so as to turn with said base, said first spring system comprising first spring means supported at one end on said base, a first spring-loading mass supported on said first spring means at a position spaced along said first spring means from said base so as to deflect said first spring means, and first electrical contact means on said first spring means at a first point spaced along said spring means from said base;

a second spring system secured to said base so as to turn with said base, said second spring system comprising second spring means supported at one end on said base, a second springloading mass supported on said second spring means at a position spaced along said second spring means from said base so as to deflect said second spring means, and second electrical contact means on said second spring system at a second point spaced along said spring means from said base;

said first spring-loading mass being spaced further along said first spring system than is said second spring-loading means to produce different periods of free vibration for said first and second spring systems and different static displacements of those ends of said first and second spring means adjacent said first and second spring-loading means, respectively;

said first and second electrical contacts being positioned so as to be spaced apart when said first and second spring systems are quiescent, and aligned so that the contact surfaces thereof are closed to each other when said first and second spring systems are deflected sufficiently in opposite directions;

said first and second spring systems differing from each other with respect to the values of at least one of the parameters of loading mass and spring stiffness, so that the static deflections of said contact surfaces are substantially the same for different values of gravitational and inertial forces acting on said spring-loading masses.

2. The motion sensor of claim 1, in which said first and second spring systems are secured to said base at adjacent positions and extend therefrom in the same direction in substantially parallel relationship to each other.

3. The motion sensor of claim 2, in which each of said first and second spring mEans comprises a cantilever-mounted leaf spring.

4. The motion sensor of claim 1, in which said first and second spring means comprise first and second coaxial helical coil springs.

5. A motion sensor, comprising:

first coil spring means;

means mounting said first coil spring means to permit steady lateral deflection and lateral vibratory motion thereof;

second coil spring means;

means mounting said second coil spring means to permit lateral steady deflection and lateral vibratory motion thereof;

said first and second coil spring means having respective first and second contact surfaces thereon positioned so that said contact surfaces are spaced from each other by substantially a fixed distance when said sensor is oriented in different quiescent positions but contact each other when said first and second coil spring means are set into vibration;

said first and second coil spring means being helical and coaxial, and said first coil spring means being positioned inside said second coil spring means.