Transducer which determines a position of an object by modifying differential pulses
First Claim
1. A transducer comprisinga magnetostrictive member comprising at least one elongated strip or wire which, in operation, acts as an acoustic delay line and is sensitive to changes in magnetic flux,two parallel conductors,means for generating current pulses in the conductors, the conductors being positioned sufficiently close to the magnetostrictive member to cause an acoustic pulse to be launched in the magnetostrictive member each time one of the said current pulses is generated,modifier means for varying the amplitudes of the acoustic pulses in dependence upon conditions at the modifier means, anddetector means for deriving electrical output signals having values dependent on the amplitudes of the acoustic pulses,the two conductors being located on either side of the elongated strip or wire parallel to one another and at a substantial angle to the strip or wire in positions where each conductor, when carrying current pulses, has an equal but opposite magnetic effect on the delay line at a datum position of the modifier means.
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Accused Products
Abstract
A force transducer which uses current pulses in a conductor to generate acoustic pulses in a magnetostrictive delay line. The pulses are sensed by a coil around the line. The magnitude of the pulses is modified by force applied to the transducer by changing the shielding effect of a magnetoelastic ribbon (between the conductor and the delay line) by applying a force to be sensed thereto. The transducers are economic and easily assembled into arrays for sensing stress distribution in two dimensions because the common conductors can be used for the columns of the array and common delay lines can be used for the array rows. Each column then has a common current-pulse generator and each row has a common detector coil. A similar technique may be used for sensing the spatial distribution of other parameters such as temperature, magnetic field or displacement.
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Citations
12 Claims
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1. A transducer comprising
a magnetostrictive member comprising at least one elongated strip or wire which, in operation, acts as an acoustic delay line and is sensitive to changes in magnetic flux, two parallel conductors, means for generating current pulses in the conductors, the conductors being positioned sufficiently close to the magnetostrictive member to cause an acoustic pulse to be launched in the magnetostrictive member each time one of the said current pulses is generated, modifier means for varying the amplitudes of the acoustic pulses in dependence upon conditions at the modifier means, and detector means for deriving electrical output signals having values dependent on the amplitudes of the acoustic pulses, the two conductors being located on either side of the elongated strip or wire parallel to one another and at a substantial angle to the strip or wire in positions where each conductor, when carrying current pulses, has an equal but opposite magnetic effect on the delay line at a datum position of the modifier means.
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7. A transducer array in combination with means arranged to be attached to the foot of a person comprising magnetic or conducting material to be located on the sole of the foot,
each transducer in the array comprising a magnetostrictive member which, in operation, acts as an acoustic delay line and is sensitive to changes in magnetic flux, a conductor, means for generating current pulses in the conductor, the conductor being positioned sufficiently close to the magnetostrictive member to cause an acoustic pulse to be launched in the magnetostrictive member each time one of the said current pulses is generated, and detector means for deriving electrical output signals having values dependent on the amplitudes of the acoustic pulses, in operation, the amplitudes of the acoustic pulses being modified in those transducers in the array which are in the vicinity of the magnetic or conducting material on the sole of a foot placed on the array.
Specification