Position sensing device

Claim 2

A position sensor, comprising: - a magnetic medium producing a magnetic field; and - a pick-up head mounted adjacent said magnetic medium for detecting said magnetic field, said pick-up head and said magnetic medium being adapted for translational movement one with respect to the other, said magnetic field having a continuously variable intensity along the direction of said translational movement, said pick-up head comprising: a) a first magnetic field detector generating an output signal representative of the intensity of said magnetic field at the position of detection thereof by said first detector; and b) a second magnetic field detector generating an output signal representative of the intensity of said magnetic field at the position of detection thereof by said second detector, said second detector being spaced from said first detector by a predetermined distance along the direction of said translational movement, said first and second detectors being adapted to be connected to a signal processing circuit deriving position information from said output signals.

Claim 3

A position sensor as defined in claim 1, wherein said first and second detectors comprise, each a magnetic core constituting means to establish a magnetic path and a magnetic flux to voltage transducer in said magnetic path.

Claim 4

A position sensor as defined in claim 2, wherein said magnetic flux to voltage transducer is a Hall effect transducer.

Claim 5

A position sensor as defined in claim 1, wherein the intensity of said magnetic field varies sinusoidally in a longitudinal direction of said magnetic medium.

Claim 6

A position sensor as defined in claim 1, further comprising a guide bar, incuding: - a metallic base plate; - a magnetic tape constituting said magnetic medium, said magnetic tape being adhesively mounted on said base plate; and - a pair of clamping bars mouted on said base plate and clamping the lateral edges of said tape.

Claim 7

A position sensor as defined in claim 5, wherein said guide bar is straight.

Claim 8

A position sensor as defined in claim 5, wherein said guide bar is annular.

Claim 9

A position sensor as defined in claim 4, wherein said magnetic field detectors are spaced apart by a distance corresponding approximately to a quarter of the wavelength of said magnetic field.

Claim 10

A torque sensor, comprising: - a rotatable torsion shaft adapted to be operatively connected to a prime mover and to a load for transmitting from said prime mover to said load torque which is to be detected, said torque producing a twist in said torque shaft; - first and second magnetic media mounted at axially spaced locations on said torsion shaft, each magnetic medium producing a magnetic field with an intensity varying in a peripheral direction of said torsion shaft; - first and second pick-up heads mounted adjacent said first and second magnetic media, respectively, for detecting the magnetic fields and generating in turn output signals, and first pick-up head including a pair of magnetic field detectors spaced apart by a predetermined distance in a peripheral direction of said torsion shaft, each magnetic field detector generating an output signal representative of the intensity of said magnetic field at the position of detection thereof by the magnetic field detector, said pick-up heads being adapted to be operatively connected to a signal processing circuit for deriving torque information from the output signals of said pick-up heads.

Claim 11

A torque sensor, comprising: - a rotatable torsion shaft adapted to be operatively connected to a prime mover and to a load for transmitting from said prime mover to said load torque which is to be detected, said torque producing a twist in said torque shaft; - first and second magnetic media mounted at axially spaced locations on said torsion shaft, each magnetic medium producing a magnetic field with an intensity varying in a peripheral direction of said torsion shaft; - first and second pick-up heads mounted adjacent said first and second magnetic media, respectively, for detecting the magnetic fields and generating in turn output signals, and first pick-up head including a pair of magnetic field detectors spaced apart by a predetermined distance in a peripheral direction of said torsion shaft, each magnetic field detector generating an output signal representative of the intensity of said magnetic field at the position of detection thereof by the magnetic field detector, said pick-up heads being adapted to be operatively connected to a signal processing circuit for deriving torque information from the output signals of said pick-up heads.

Claim 12

A device as defined in claim 9, wherein said second pick-up head includes a single magnetic field detector.

Claim 13

A device as defined in claim 9, wherein each magnetic field detector includes a magnetic core establishing a magnetic path, and a magnetic flux to voltage transducer in said path.

Claim 14

A device as defined in claim 11, wherein said magnetic flux to voltage transducer is a Hall effect transducer.

Claim 15

A device as defined in claim 10, wherein the magnetic field detector of said second pick-up head includes a magnetic core establishing a magnetic path, and a magnetic flux to voltage transducer placed in said magnetic path.

Claim 16

A device as defined in claim 13, wherein said magnetic flux to voltage transducer is a Hall effect tranducer.

Claim 17

A device as defined in claim 9, wherein each of said magnetic fields varies sinusoidally.

Claim 18

A device as defined in claim 15, wherein the magnetic field detectors of said first pick-up head are spaced apart from each other by a quarter of the wavelength of said magnetic field.