Strain gauge

Claim 1

A FORCE MEASURING DEVICE COMPRISING A SUPPORT MEMBER HAVING A PAIR OF SPACED PROJECTING ARMS AND FORMED OF FUSED QUARTZ, AT LEAST ONE ELONGATED SENSOR ELEMENT HAVING AN ELECTRICAL RESISTANCE VARIABLE IN RESPONSE TO VARIATION IN ITS TENSION IN THE DIRECTION OF ITS LENGTH AND CONNECTED AT ITS ENDS BETWEEN SAID SPACED ARMS, MEANS ENGAGEABLE WITH ONE END OF THE SENSOR ELEMENT AND RESPONSIVE TO AN APPLIED FORCE FOR SUBJECTING SAID ELEMENT TO A CHANGE IN TENSION IN THE DIRECTION OF ITS LENGTH FROM AN INITIAL VALUE, SAID LAST-NAMED MEANS COMPRISING A BAR OF FUSED QUARTZ, TORSION HINGES OF FUSED QUARTZ CONNECTING THE ENDS OF THE BAR TO THE SUPPORT FOR ROTATION OF THE BAR ABOUT ITS LONGITUDINAL AXIS, MEANS EXTENDING BETWEEN THE BAR AND ONE END OF THE SENSOR ELEMENT FOR CONVERTING A ROTATIONAL FORCE ON SAID BAR TO A LINEAR FORCE ON THE SENSOR ELEMENT IN THE DIRECTION OF ITS LENGTH, PRESSURE SENSITIVE MEANS FOR APPLYING A ROTATIONAL FORCE TO THE BAR, AND ELECTRICAL MEANS COUPLED TO THE ENDS OF AT LEAST ONE SENSOR ELEMENT FOR DETECTING VARIATIONS IN ITS RESISTANCE IN ACCORDANCE WITH CHANGES IN THE MAGNITUDE OF THE FORCE.