Abstract: A propeller system has a pair of hub assemblies driven in counter-rotation, each hub assembly having a mechanical pitch change actuator, each actuator being provided with a pitch lock that rotates simultaneously with the motion of the actuator to allow the actuator to set propeller blade pitch, but locks the propeller blade positionally when not rotating simultaneously with the actuator, and a differential for transmitting a pitch change signal across a rotating gap between the two hub assemblies and for providing power to a means for providing the pitch change signals. A pair of motors provide the rotative signal to set the pitch of the blades in each hub assembly. One of the pair of motors drives the actuator towards high pitch and the other motor drives the actuator towards low pitch. A synchronizer coordinates the signals of the first and second motors so that a pitch lock moves simultaneously with the actuator.

Abstract: A master controller 14 on the stationary side of a propeller system 10 sends pitch control signals via a communications link 34 which comprises a pair of capacitors 64, 66, each capacitor having a stationary plate and a rotating plate, one capacitor forming a high potential signal path, the other capacitor forming a low potential return path, across a rotating gap to a slave controller 54 on the rotating side of the propeller system which sets blade pitch according to the pitch control signals and sends pitch position signals back through the communications link to the master controller.

Abstract: A pitch control system for a multibladed variable pitch wind turbine. Each of the turbine blades is pivotally driven about the longitudinal axis thereof independently of the other blades by at least a pair of hydraulic actuators. The actuators are supplied with pressurized hydraulic fluid from a first source thereof under conditions of normal pitch change adjustment. Under conditions wherein feathering of the blades is required, the actuators are supplied with hydraulic fluid from second sources thereof such that one of the actuators associated with each of the blades is supplied with fluid from one second source and a second actuator is provided with fluid from a redundant second source whereby blade feathering may be effected despite a malfunction of one of the redundant sources or one of the actuators.

Abstract: Where a single output gear is driven from a single input pinion through a pair of idler gears and equal torque division between the two idlers is accomplished by floating the input pinion between the two idlers in a yoke that is hinged to the gear housing by spaced hinge pins. One hinge pin is located on the resultant load line from the points where the pinion meshes with the idlers and the other pin has a small clearance to allow the yoke to pivot about the first or loaded pin. Lubrication by oil under pressure for both pins assures a damping action at the loose pin.