Lightweight torquemeter and torque-measuring method
First Claim
1. A method for measuring levels of torque in a rotating member comprising the steps of:
- forming onto said rotating member a magnetostrictive element comprising a core constructed from material of low magnetic coercivity and a jacket about said core constructed from material of high magnetic coercivity;
resetting the magnetic polarity of said core from a triggered state wherein said core polarity is unidirectional with respect to the magnetic polarity of said jacket to a reset state wherein said core polarity is oppositely directed with respect to said jacket polarity;
triggering an avalanche Barkhausen reversal of said core polarity from said reset state to said triggered state;
generating a signal responsive to said avalanche Barkhausen reversal; and
correlating said responsive signal to an indication of the level of torque in said rotating member.
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Accused Products
Abstract
A torquemeter 10 comprising a magnetostrictive element 12 which is formed in the shape of a ribbon upon the surface of the subject rotating member 14 and is capable of producing internal, avalanche Barkhausen reversals, permanent magnets 16 and 18 positioned adjacent to the subject rotating member 14 for successively triggering the avalanche Barkhausen reversals in the magnetostrictive element and for resetting the magnetostrictive element after each reversal, a pickup coil 20 for generating signals responsive to the avalanche Barkhausen reversals and a readout circuit 22 in communication with pickup coil 20 for correlating the responsive signals to an indication of the level of torque and/or power in the subject rotating member 14.
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Citations
20 Claims
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1. A method for measuring levels of torque in a rotating member comprising the steps of:
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forming onto said rotating member a magnetostrictive element comprising a core constructed from material of low magnetic coercivity and a jacket about said core constructed from material of high magnetic coercivity; resetting the magnetic polarity of said core from a triggered state wherein said core polarity is unidirectional with respect to the magnetic polarity of said jacket to a reset state wherein said core polarity is oppositely directed with respect to said jacket polarity; triggering an avalanche Barkhausen reversal of said core polarity from said reset state to said triggered state; generating a signal responsive to said avalanche Barkhausen reversal; and correlating said responsive signal to an indication of the level of torque in said rotating member. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An apparatus for measuring levels of torque in a rotating member comprising:
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a magnetostrictive element formed onto said rotating member comprising a core constructed from material of low magnetic coercivity and a jacket about said core constructed from material of high magnetic coercivity; reset means for resetting the magnetic polarity of said core from a triggered state wherein said core polarity is unidirectional with respect to the magnetic polarity of said jacket to a reset state wherein said core polarity is directed oppositely with respect to said jacket polarity; triggering means for triggering an avalanche Barkhausen reversal of said core polarity from said reset state to said triggered state; means for generating a signal responsive to said avalanche Barkhausen reversal; and means for correlating said responsive signal to an indication of the level of torque in said shaft. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. An apparatus for measuring levels of torque in a rotating member comprising:
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a magnetostrictive element formed onto said member capable of producing avalanche Barkhasuen reversals; means for successively triggering avalanche Barkhausen reversals in said magnetostrictive element and for resetting said magnetostrictive element after each reversal; means for generating a signal responsive to said avalanche Barkhausen reversals; and means for correlating said responsive signal to an indication of the level of torque in said member.
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Specification