Method and apparatus for measuring the oscillation of vanes, particularly in jet propelling units

Claim 1

A METHOD FOR TESTING ROTARY OR NON-ROTARY VANES OR BLADES OF TURBO-ENGINES THROUGH THE USE OF ELECTRIC SIGNAL PULSE-GENERATING MEANS ARRANGED AT PARTICULAR POINTS AROUND THE PERIPHERY OF THE BLADES OR VANES AND MEANS FOR PRODUCING AN APPROPRIATE TIME BASE DISPLAY, THE METHOD COMPRISING GENERATING A FIRST ELECTRIC SIGNAL PULSE AT THE TIME AT WHICH A SYNCHRONIZING REFERENCE POINT ON THE ROTOR OF THE TURBO-ENGINE WHICH LOCATES A RADIUS VECTOR ROTATING RIGIDLY WITH THE ROTOR PASSES A FIXED POINT IN SPACE ADJACENT THE ROTOR, GENERATING A SECOND ELECTRIC SIGNAL PULSE AT THE TIME AT WHICH THE TIP OF A SELECTED BLADE OR VANE PASSES A SECOND FIXED POINT, TRIGGERING THE TIME SCAN OF THE TIME BASE DISPLAY WITH THE FIRST SIGNAL PULSE, AND MODULATING THE TIME SCAN THUS TRIGGERED WITH THE SECOND SIGNAL PULSE WHEREBY THE MAGNITUDE, ANGULAR POSITION, AND DURATION OF THE SECOND SIGNAL PULSE IS DISPLAYED TOGETHER WITH APPROPRIATE CALIBRATION MARKS FOR ASCERTAINING THE OSCILLATION FREQUENCY AND ANGULAR DISPLACEMENT OF THE BLADE TIPS.