Radio-frequency tuned-circuit microdisplacement transducer
First Claim
Patent Images
1. In a strain-stress detecting system comprising:
- an elongated integral fastener member subject to elastic deformation when stressed wherein one portion thereof moves relative to another portion;
a resonant circuit assembly carried by said member, said assembly comprising a body of electrical insulating material on said member;
an electrical coil on one surface of said body;
a first capacitor plate on an opposite surface of said body and first means electrically connecting said capacitor plate to one end of said coil;
a second capacitor plate adjacent and movable toward and from said first plate and second means electrically connecting said second plate to the other end of said coil whereby said coil and plates define a resonant circuit; and
one of said plates being fixed relative to one of said portions of said member and the other plate being fixed relative to the other portion whereby elastic deformation of said member will vary the resonant frequency of said circuit.
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Abstract
An inductance-capacitance loop defines a resonant circuit and is arranged in a member subject to stress. Strains resulting from the stress vary the inductance or capacitance of the circuit, and its resonant frequency. A dip meter is used to detect the resonant frequency and thus provides a reading indicative of the stress in the member.
42 Citations
8 Claims
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1. In a strain-stress detecting system comprising:
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an elongated integral fastener member subject to elastic deformation when stressed wherein one portion thereof moves relative to another portion; a resonant circuit assembly carried by said member, said assembly comprising a body of electrical insulating material on said member; an electrical coil on one surface of said body; a first capacitor plate on an opposite surface of said body and first means electrically connecting said capacitor plate to one end of said coil; a second capacitor plate adjacent and movable toward and from said first plate and second means electrically connecting said second plate to the other end of said coil whereby said coil and plates define a resonant circuit; and one of said plates being fixed relative to one of said portions of said member and the other plate being fixed relative to the other portion whereby elastic deformation of said member will vary the resonant frequency of said circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A transducer comprising a foldable sheet of electrical insulating material having at least one flat spiral conductive coil on a surface thereof, a pair of conductive capacitor plates covering different surface areas of said sheet, said plates being respectively electrically connected to opposite ends of said coil, and said sheet being folded to place said plates in opposition to each other with one of said plates being movable toward and from the other plate by flexure of said sheet material to vary the frequency of the tuned circuit defined by said plates and coil.
Specification