Abstract: This patent discloses improvements over a mechanism to modulate the pitch of the blades of a fan, turbine or propeller driven by a rotating shaft bearing a helical thread onto which a nut made of a ferromagnetic material was threaded; this nut was spun by electromagnets disposed about it on the stator system and its resultant axial motion manipulated the blades' pitch. This patent discloses refinement of control of the electromagnets employed to spin the axial modulator by embedding a plurality of ferrous protuberances in this nut—the rotational position of which is determined via metallic edge detection sensors whose logic levels are used to selectively energize electromagnets that apply a force onto the protuberances in order to induce rotation and axial motion on the nut. This additional degree of rotational freedom is controlled by this reluctance-motor like configuration while a second motor is used to spin the blades.

Abstract: Efficient motor commutation has in the past been challenged by limitations of shaft positioning sensors and a microcontroller's complex algorithms employed to switch an inverter once the shaft's position is inferred. While counter intuitive, this invention purports to do away with the complexities of typical field-oriented control by transferring control back into the analog domain. A magneto-resistive sensor generates precisely the waveform which an inverter would typically generate but with fixed amplitude; therefore, this sensor's output is fed into a voltage-controlled amplifier (VCA) followed by a class-d amplifier then fed to the motor's phases. The effect is to reduce the motor commutation problem to an audio amplifier; a greatly simplified microcontroller can then be used to sample the motor's position and vary a voltage command line to the VCA to achieve speed control.

Abstract: This invention employs a generic axial modulating mechanism to manipulate the pitch of the blades of a fan or propeller; conceptually, this is a threaded bolt and nut where the threaded bolt would be analogous to a rotating shaft, with an acme thread (i.e. the “rotor thread”) on its exterior, and the nut would be analogous to the axial modulator of this teaching. The “nut,” or axial modulator, is further spun above and beyond the rotation in the rotating bolt or rotating shaft. The axial motion of the axial modulator is then deployed to do useful work i.e. manipulate the pitch of the blades of a fan or propeller. This invention is a continuation in part of a previous variant disclosed where the means of modulating the axial modulator was magnetic. The variation introduced in this teaching instead achieves the modulation using a gear-driven arrangement.

Abstract: This patent discloses improvements over a mechanism to modulate the pitch of the blades of a fan, turbine or propeller driven by a rotating shaft bearing a helical thread onto which a nut made of a ferromagnetic material was threaded; this nut was spun by electromagnets disposed about it on the stator system and its resultant axial motion manipulated the blades' pitch. This patent discloses refinement of control of the electromagnets employed to spin the axial modulator by embedding a plurality of ferrous protuberances in this nut—the rotational position of which is determined via metallic edge detection sensors whose logic levels are used to selectively energize electromagnets that apply a force onto the protuberances in order to induce rotation and axial motion on the nut. This additional degree of rotational freedom is controlled by this reluctance-motor like configuration while a second motor is used to spin the blades.

Abstract: The apparatus employs magnetoresistive sensors (28) to generate a sinusoid having a time-varying instantaneous frequency commensurate with the instantaneous frequency of the angular displacement of a motor's rotating shaft (40). The resultant signal is then fed to a mixture of fixed-phase-shifting circuits (22) whose outputs are then amplified by voltage-controlled amplifiers and fed to independently wired stator phases (56).

Abstract: The invention describes a mechanism to cause an actuator born on a rotating shaft to modulate backwards and forwards independently of the motion of the rotating shaft. This mechanism is then used to realize a controllable-pitch blade fan. The axial modulating mechanism is achieved by mounting a thread on the rotating shaft onto which an axial modulator, with a cylindrical cavity having a mating thread, is mounted; magnets induce the axial modulator to rotate independently of the shaft's rotation in turn causing the axial modulator to move linearly along the shaft. This mechanism's linear motion is then used to force blades rotatably mounted on the shaft to rotate and consequently vary their pitch.

Abstract: This invention employs a generic axial modulating mechanism to manipulate the pitch of the blades of a fan or propeller; conceptually, this is a threaded bolt and nut where the threaded bolt would be analogous to a rotating shaft, with an acme thread (i.e. the “rotor thread”) on its exterior, and the nut would be analogous to the axial modulator of this teaching. The “nut,” or axial modulator, is further spun above and beyond the rotation in the rotating bolt or rotating shaft. The axial motion of the axial modulator is then deployed to do useful work i.e. manipulate the pitch of the blades of a fan or propeller. This invention is a continuation in part of a previous variant disclosed where the means of modulating the axial modulator was magnetic. The variation introduced in this teaching instead achieves the modulation using a gear-driven arrangement.

Abstract: The apparatus employs magnetoresistive sensors (28) to generate a sinusoid having a time-varying instantaneous frequency commensurate with the instantaneous frequency of the angular displacement of a motor's rotating shaft (40). The resultant signal is then fed to a mixture of fixed-phase-shifting circuits (22) whose outputs are then amplified by voltage-controlled amplifiers and fed to independently wired stator phases (56).

Abstract: The invention describes a mechanism to cause an actuator born on a rotating shaft to modulate backwards and forwards independently of the motion of the rotating shaft. This mechanism is then used to realize a controllable-pitch blade fan. The axial modulating mechanism is achieved by mounting a thread on the rotating shaft onto which an axial modulator with a cylindrical cavity having a mating thread is mounted; magnets induce the axial modulator to rotate independently of the shaft's rotation in turn causing the axial modulator to move linearly along the shaft. This mechanism's linearly motion is then used to force blades rotatably mounted on the shaft to rotate.