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US 4,882,936 AGranted
Magnetoelastic torque tool
AssigneeMag Dev Inc.
InventorIvan J. Garshelis
Life of this patent
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AssigneeMag Dev Inc.
InventorIvan J. Garshelis
Estimating the term…
A hand tool for applying torque to a fastener includes a portion for engaging the fastener, a handle to which torque is hand-applied and a torque carrying member operatively coupled with the handle and the fastener-engaging portion for transmitting the hand-applied torque to the fastener. The torque carrying member includes a magnetoelastic torque transducer comprising a ferromagnetic, magnetostrictive region affixed to, associated with or forming a part of the surface of the torqued member for altering in magnetic premeability in response to the application of torque to the member. Additionally, the transducer includes a magnetic source for applying a cyclically time varying magnetic field to the ferromagnetic, magnetostrictive region for sensing the change in permeability caused by the applied torque, apparatus/circuitry for converting the sensed change in permeability to an electrical signal indicative of the magnitude of the torque applied to the member and an indicator responsive to the electrical signal for providing an indication that a predetermined torque has been applied to the fastener. The ferromagnetic, magnetostrictive region is advantageously formed of nickel maraging steel, desirably 18% Ni maraging steel. Preferably, the transducer comprises a pair of axially spaced-apart annular bands defined within the ferromagnetic, magnetostrictive region, the bands being endowed with residual stress created, respectively symmetrical right and left hand helically directed magnetic anisotropy of sufficiently large magnitude that the contribution to total magnetic anistropy of any random anisotropy in the member is negligible.
A hand tool for applying torque to a fastener including fastener-engaging means, handle means to which torque is hand-applied and torque carrying means operatively coupled with said handle means and said fastener-engaging means for transmitting the hand-applied torque to the fastener, said torque carrying means including a magnetoelastic torque transducer, said torque carrying means comprising a member having a ferromagnetic and magnetostrictive region formed of nickel maraging steel, said transducer comprising:
A hand tool for applying torque to a fastener including fastener-engaging means, handle means to which torque is hand-applied and torque carrying means operatively coupled with said handle means and said fastener-engaging means for transmitting the hand-applied torque to the fastener, said torque carrying means comprising a member including a magnetoelastic torque transducer, ferromagnetic, magnetostrictive means associated with said member for altering in magnetic permeability in response to the application of torque to said member, means for applying a cyclically time varying magnetic field to said ferromagnetic magnetostrictive means, means for sensing the change in permeability caused by said applied torque, and means for converting said sensed change in permeability to an electrical signal indicative of the magnitude of the torque applied to said member, and indicator means responsive to said electrical signal for providing an indication that a predetermined torque has been applied to said fastener, the improvement comprising forming said ferromagnetic, magnetostrictive means from nickel maraging steel.
A hand tool for applying torque to a fastener including fastener-engaging means, handle means to which torque is hand-applied and torque carrying means operatively coupled with said handle means and said fastener-engaging means for transmitting the hand-applied torque to the fastener, said torque carrying means including a magnetoelastic torque transducer, said torque carrying means comprising a member having a ferromagnetic and magnetostrictive region, said transducer comprising:
Dependencies are inferred from the claim text.