Force transducers for use in arrays
First Claim
1. A force transducer comprisinga 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,a force receiving member,modifier means for varying the amplitudes of the acoustic pulses in dependence upon force applied to the force receiving member, anddetector means for deriving electrical output signals having values dependent on the amplitudes of the acoustic pulses.
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Accused Products
Abstract
A force transducer is described 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 either by changing the shielding effect of a magnetoelastic ribbon (between the conductor and the delay line) by applying a force to be sensed thereto, or in another alternative by modifying the distance between the conductor and the delay line in accordance with applied force. 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.
18 Citations
24 Claims
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1. A force transducer 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, a force receiving member, modifier means for varying the amplitudes of the acoustic pulses in dependence upon force applied to the force receiving member, and detector means for deriving electrical output signals having values dependent on the amplitudes of the acoustic pulses.
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18. A force transducer array comprising a plurality of force transducers each 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, a force receiving member, modifier means for varying the amplitudes of the acoustic pulses in dependence upon force applied to the force receiving member, and detector means for deriving electrical output signals having values dependent on the amplitudes of the acoustic pulses.
Specification