Abstract: This invention relates to a blade pitch control mechanism and in particular to a blade pitch control mechanism for a turbine. The invention has been developed primarily for controlling the pitch of a plurality of blades of a turbine in an ocean wave energy extracting system. According to one aspect of the present invention provides a blade pitch control mechanism (1) for a turbine rotor (3) in an ocean wave energy extracting system, the mechanism including a gear assembly (5) mountable to a hub (7) of the rotor (3) for engaging a plurality of blades (9) rotatably mounted to the hub (7). Driving means (11) is operatively connected to the gear assembly (5) for rotating the gear assembly about an axis of the rotor (3), such that the driving means (11) rotates the gear assembly (5) at substantially the same speed as the rotational speed of the rotor (3) to fix the position of the blades (9) relative to the hub (7).

Abstract: The invention relates to wave powered energy extraction systems and the components thereof, in which the oscillating ocean wave motion is used to displace a volume of air to drive a wind operated turbine connected to an electrical generator. The various aspects of the invention include: a parabolic or part parabolic wave focusing device (1); an air compression chamber arrangement particularly suited for use with the wave focusing device; a wind turbine operable to rotate unidirectionally under periodically reversing air flow conditions of the kind contemplated above.

Abstract: The invention relates to wave powered energy extraction systems and the components thereof, in which the oscillating ocean wave motion is used to displace a volume of air to drive a wind operated turbine connected to an electrical generator. The various aspects of the invention include: a novel parabolic or part parabolic wave focusing device (1); an air compression chamber arrangement particularly suited for use with the novel wave focusing device; and an independently novel wind turbine operable to rotate unidirectionally under periodically reversing air flow conditions of the kind contemplated above.

Abstract: A parabolic or part parabolic focusing device located in the ocean comprises wall sections which converge a parallel ocean wavefront to foci located in an air compression chamber located between the wall sections, thereby providing a wave amplification effect. An oscillating wave surface produces an oscillating air column inside the chamber to drive a self-rectifying turbine located in an outlet at the top of the chamber. The turbine comprises a rotor with radially oriented aerofoil shaped blades which are symmetrical in cross section about a transverse plane so that the turbine rotates in a single direction regardless of the oscillations in the air column. Several mechanisms to vary the pitch of the blades are also disclosed.