Helicopter rotor construction

Claim 1

IN A HELICOPTER ROTOR CONSTRUCTION INCLUDING A ROTATABLE ROTOR HEAD, A PLURALITY OF ROTOR BLADES EACH PIVOTALLY MOUNTED AT THEIR INNER ENDS ON SAID ROTOR HEAD FOR PERIODIC PIVOTAL LEAD-LAG MOVEMENT ABOUT A LEAD-LAG AXIS SUBSTANTIALLY PARALLEL TO THE AXIS OF ROTATION OF SAID ROTOR IN AGREEMENT WITH THEIR NATURAL FREQUENCY, SAID ROTOR BLADES INCLUDING AT LEAST ONE HYDRAULIC SYSTEM CONNECTED TO SAID ROTOR HEAD AND OPERATED BY ROTATION OF SAID ROTOR HEAD AND ALSO CONNECTED TO SAID BLADES FOR SHIFTING THE LATTER ABOUT THEIR LEAD-LAG AXES DURING ROTATION OF SAID HEAD, SAID HYDRAULIC SYSTEM INCLUDING: AT LEAST OINE ACTUATING CYLINDER MOUNTED ON SAID ROTOR HEAD WITH AN ACTUATING PISTON SLIDABLE THEREIN SEPARATELY CONNECTED TO EACH BLADE FOR SHIFTING THE CONNECTED BLADE ABOUT ITS LEAD-LAG AXIS FOR MOVING ALL OF SAID ROTOR BLADES IN ACCORDANCE WITH THE PENDULUM FREQUENCY OF SAID ROTOR BLADES AS SAID HEAD IS ROTATED AND PUMP MEANS CONNECTED TO SAID ACTUATING CYLINDER FOR SUPPLYING FLUID THERETO FOR CONTROLLING THE MOVEMENT OF SAID ACTUATING PISTON; AND MEANS CONNECTED TO SAID PUMP MEANS AND TO SAID ROTOR TO ACTUATE SAID PUMP MEANS TO RECIPROCATEE SAID ACTUATING PISTON IN TIMED RELATION TO THE ROTATION OF SAID ROTOR HEAD.