Stress sensor and control system for limiting stresses applied to aircraft

Claim 1

A FLEXURAL STRESS SENSOR FOR MEASURING THE STRESS OF AN ELONGATED STRUCTURAL MEMBER ON WHICH THE SENSOR MAY BE EFFECITVELY MOUNTED, COMPRISING A LIGHT SOURCE AND LENS SYSTEM RIGIDLY MOUNTED TO ONE PORTION OF THE ELONGATED STRUCTUREAL MEMBER, AND TWO PHOTO SENSITIVE ELEMENTS RIDIGLY MOUNTED AT ANOTHE RPORTION ON THE STRUCTURAL MEMBER LONGITUDINALLY SPACED FROM THE ONE PORTION AND IN SUCH PROXIMITY TO THE LIGHT SOURCE AND LENS THAT A BEAM OF LIGHT FROM THE SOURCE WILL FALL SUBSTANTIALLY PERPENDICULAR ON BOTH PHOTO SENSITIVE ELEMENTS WHEN THE MEMBER IS UNFLEXED; A NORMALLY BALANCED ELECTRICAL BRIDGE, TWO LEGS OF WHICH CONTAIN THE PHOTO SENSITIVE ELEMENTS, THE REMAINING LEGS HAVING SUITABLE IMPEDANCE TO ELECTRICALLY BALANCE THE BRIDGE WHEN THE BEAM IS IN AN UNFLEXED POSITION; A DETECTING DEVICE OPERATIVELY CONNECTED TO THE BRIDGE AND INCLUDING A STRESS INDICATING MEANS, THE LIGHT SOURCE, LENS SYSTEM, AND PHOTO SENSITIVE ELEMENTS BEING SO MOUNTED IN SAID LONGITUDINAL SPACED RELATION ON THE ELONGATE STRUCTURAL MEMBER THAT DEFLECTION THEREOF IN ONE DIRECTION WILL CAUSE THE PHOTO SENSITIVE ELEMENTS TO MOVE PERPENDICUAL TO THE LIGHT SOURCE IN SAID ONE DIRECTION TO CAUSE LIGHT FALLING ON ONE PHOTO SENSITIVE ELEMENT TO INCREASE AND ON THE OTHER PHOTOSENSITIVE ELEMENT TO DECREASE THEREBY UNBALANCING THE BRIDGE TO EFFECT OPERATION OF THE DETECTOR CAUSING THE INDICATOR MEANS OF THE DETECTOR TO INDICATE A DIFFERENTIAL AMPLITUDE AND PHASE VARIATION IN STRESS SIGNALS PROPORTIONAL TO THE DEFLECTION OF SAID ELONGATED STRUCTURAL MEMBER.