Patent ID: 6581478
Filing Date: 2003-06-24
Classification: G01L,Y10S

Abstract:
An apparatus for measuring torque in a torsion member, that apparatus comprising:a transducer adapted to be attached to the torsion member and having a first resonant frequency which changes with variation of strain in the torsion member; a transducer oscillator connected to the transducer and producing a first signal having a first frequency that is a function of the first resonant frequency; a reference element having a second resonant frequency that is unaffected by variation of strain in the torsion member; a reference oscillator connected to the reference element and producing a second signal having a second frequency that is a function of the second resonant frequency; and a mixer connected to the transducer oscillator and to the reference oscillator to heterodyne the first signal and second signal thereby producing a resultant signal having a frequency which corresponds to torque applied to in the torsion member.