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US 4,667,158 AGranted
Linear position transducer and signal processor
OwnerRobert W. Redlichinventor
Life of this patent
Estimating the term…
Abstract
Disclosed are a transducer for converting linear motion of a core into a proportional change in inductance by means of skin effect, and bridge processing circuitry for stable conversion of changing inductance into a proportional voltage.
Claims15
A linear position measurement apparatus including a transducer comprising:
- (a) a tube of electrically insulating material having a length at least substantially four times its outside diameter;
- (b) a helical, conducting coil wound around the tube and at least substantially four of said diameters long;
- (c) an elongated core of electrically conducting, non-ferromagnetic material matingly received within and slidable in axial reciprocation within the tube;
- and
- (d) a non-conductive, ferromagnetic, tubular layer surrounding the coil and at least substantially four of said diameters long, said layer having substantially uniform radial dimensions along its length.
2 more elements
A linear position measurement apparatus comprising:
- (a) a tube of electrically insulating material having a length at least substantially four times its outside diameter;
- (b) a helical conductor coil having a skin depth dependent upon frequency and wound around the tube and at least substantially four of said diameters long, said coil being substantially a single layer of windings having a uniform conductor spacing along its length and a radial thickness not greater than substantially the skin depth of the coil conductor at a selected operating frequency;
- (c) an elongated core of electrically conducting, non-ferromagnetic material matingly received within and slidable in axial reciprocation within the tube;
- (d) a non-conductive, ferromagnetic, tubular layer surrounding the coil and at least substantially four of said diameters long, said layer having substantially uniform radial dimensions along its length;
- and
- (e) a tubular, electrically conductive, ferromagnetic shield surrounding said ferromagnetic layer along essentially the entire length of the coil.
3 more elements
Dependencies are inferred from the claim text.