Vibration damping mechanism

Claim 1

AN AIRCRAFT SUSTANING ROTOR INCLUDING A ROTOR HUB, A THRUST-PRODUCING ROTOR BLADE DISPOSED IN A GENERALLY RADIAL POSITION WITH RESPECT TO THE AXIS OF THE HUB, HINGING MEANS INTERCONNECTING THE BLADE AND HUB SUCH THAT ROTATION OF THE HUB CAUSES THE BLADE TO TRAVEL IN A CIRCULAR PATH AROUND THE HUB AXIS AND SUCH THAT OSCILLATING MOVEMENTS OF THE BLADE RELATIVE TO THE HUB CAN OCCUR IN THE CIRCULAR PATH DURING HUB ROTATION, AND A DAMPING MECHANISM OF A CHARACTER SUCH THAT ANY OSCILLATING BLADE MOVEMENTS OCCURRING DURING HUB ROTATION PRODUCE DAMPING FORCES EFFECTING ATTENUATION OF SAID OSCILLATING BLADE MOVEMENTS AND SUCH THAT SAID DAMPING FORCES ARE INVERSELY AFFECTED BY THE OSCILLATING FREQUENCY OF SAID OSCILLATING MOVEMENTS, SAID DAMPING MECHANISM COMPRISING: A SOURCE OF PRESSURIZED LIQUID; ENERGY-DISSIPATING MEANS CHARACTERIZED BY FIRST AND SECOND LIQUID-FILLED VARIABLE-VOLUME COMPARTMENTS, SAID MEANS BEING INTERCONNECTED BETWEEN THE ROTOR HUB AND ROTOR BLADE SUCH THAT OSCILLATING BLADE MOVEMENTS CAUSE COMPARTMENT VOLUME VARIATIONS EFFECTING PRESSURIZATION OF THE LIQUID IN SAID COMPARTMENTS; FIRST LIQUID-CONDUCTING MEANS RESPONSIVE TO THE UNIT PRESSURE OF THE LIQUID IN SAID SOURCE FOR CONDUCTING LIQUID FROM SAID SOURCE INTO THE FIRST COMPARTMENT OF THE ENERGY-DISSIPATING MEANS WHEN THE UNIT PRESSURE OF THE SOURCE LIQUID EXCEEDS THE UNIT PRESSURE OF THE FIRST COMPARTMENT LIQUID; SECOND LIQUID-CONDUCTING MEANS RESPONSIVE TO THE UNIT PRESSURE OF THE LIQUID IN SAID FIRST COMPARTMENT FOR CONDUCTING LIQUID FROM SAID FIRST COMPARTMENT INTO THE SECOND COMPARTMENT OF THE ENERGY-DISSIPATING MEANS WHEN THE UNIT PRESSURE OF THE FIRST COMPARTMENT LIQUID EXCEEDS THE UNIT PRESSURE OF THE SECOND COMPARTMENT LIQUID; THIRD LIQUID-CONDUCTING MEANS FOR CONDUCTING LIQUID FROM SAID SECOND COMPARTMENT INTO THE SOURCE OF LIQUID WHEN THE UNIT PRESSURE OF THE SECOND COMPARTMENT LIQUID ATTAINS A PRESELECTED MAXIMUM MAGNITUDE; AND MEANS RESPONSIVE TO OSCILLATING BLADE MOVEMENTS FOR BY-PASSING SAID THIRD MEANS FOR CONDUCTING LIQUID FROM THE SECOND COMPARTMENT OF THE ENERGY-DISSIPATING MEANS INTO THE SOURCE OF LIQUID AT UNIT PRESSURES BELOW SAID MAXIMUM MAGNITUDE AND ABOVE A PRESELECTED MINIMUM MAGNITUDE SUCH THAT LIQUID PRESSURIZATION IN SAID ENERGY-DISSIPATING MEANS IS REDUCED WHEN THE OSCILLATION FREQUENCY OF SAID OSCILLATING BLADE MOVEMENTS EXCEEDS A PRESELECTED FREQUENCY MAGNITUDE.