Abstract: An object of the present invention is to provide a natural energy extraction apparatus comprising a vertical rotating shaft and a float for supporting the vertical rotating shaft, wherein the internal structure of the float is simpler, the float and a mooring apparatus are more compact, and production cost is lower than in the conventional natural energy extraction apparatus. A natural energy extraction apparatus comprises a first float forming a swingable vertical rotating shaft, a second float moored to surround the first float, and a power transmission device attached to the second float to convert rotational kinetic energy of the first float to driving torque for driven equipment, and the natural energy extraction apparatus is installed on a body of water.

Abstract: The present invention provides a drag-type turbine capable of efficiently extracting kinetic energy of fluid particles orbiting in waves and a wave power generator comprising said drag-type turbine. This turbine is a single bucket drag-type turbine with a single half-pipe bucket and a counterweight oppositely facing the bucket, where fluid particles in orbital motion in a wave impel the bucket and the counterweight to rotate them as a unitary body.

Abstract: An object of the present invention is to provide a natural energy extraction apparatus which can extract kinetic energies of river water currents or tidal water currents at various depth layers, and which is easy to attach to the fixed structure above water current. A natural energy extraction apparatus comprises a float, a vertical-axis water turbine fixed to the float and extending downward, a power transmission device engaging an upper end of the float and converting rotational kinetic energy of the float to driving torque for driven equipment, and arm members supporting the power transmission device rotatably around a horizontal axis at one ends and supported by a fixed structure above a water current rotatably around a horizontal axis at the other ends, wherein the float and the vertical-axis water turbine are located in a river water current or tidal water current.

Abstract: An object of the present invention is to provide a natural energy extraction apparatus comprising a vertical rotating shaft and a float for supporting the vertical rotating shaft, wherein the internal structure of the float is simpler, the float and a mooring apparatus are more compact, and production cost is lower than in the conventional natural energy extraction apparatus. A natural energy extraction apparatus comprises a first float forming a swingable vertical rotating shaft, a second float moored to surround the first float, and a power transmission device attached to the second float to convert rotational kinetic energy of the first float to driving torque for driven equipment, and the natural energy extraction apparatus is installed on a body of water.

Abstract: An object of the present invention is to provide a natural energy extraction apparatus which can extract kinetic energies of river water currents or tidal water currents at various depth layers, and which is easy to attach to the fixed structure above water current. A natural energy extraction apparatus comprises a float, a vertical-axis water turbine fixed to the float and extending downward, a power transmission device engaging an upper end of the float and converting rotational kinetic energy of the float to driving torque for driven equipment, and arm members supporting the power transmission device rotatably around a horizontal axis at one ends and supported by a fixed structure above a water current rotatably around a horizontal axis at the other ends, wherein the float and the vertical-axis water turbine are located in a river water current or tidal water current.