US 8456030 B2 / Jun 4, 2013

Power take off apparatus for a WEC

A wave energy converter (WEC) includes a float which moves generally in phase with the waves and whose up and down motion is guided by and along a spar having an upper portion and a lower portion. A power take off (PTO) device is coupled between the float and the spar for converting their relative motion into useful energy. In some embodiments, the PTO includes (a) a drum having an axis of rotation rotatably mounted within one of the float and spar; and (b) cabling means connected between the drum and the other one of the float and spar for causing the drum to rotate as a function of the up and down motion of the float. In other embodiments, the PTO system is formed using a pre-tensioned roller chain wound around sprocket wheels located within one of the spar and float with the opposite ends of the chain connected to the other one of the spar and float to cause rotation of the sprocket wheels in response to movement of the float relative to the spar.