Abstract: As for the floodgate which it flows into one-way from a tide level, the High Water Source flowing in is made, and the Low Water Source flowing out is made. A tank is located between these Water Sources, repetition of the feed water from a high-water level, and the drain to a low-water level, it generates electricity by rotating a air turbine by the pressure in a Tank. As for the method of the improvement in efficiency, a turbine is set to Air Duct between two sets of tanks, the double electric power is obtained by interlocking with opposite feed water and drain. Moreover, the variation of electric power is improved by shifting the cycle of the tank of parallel movement. And it responds to water level in a tank, the stable production of electricity is obtained by the drive of selection of the turbine of the capacity difference of a parallel drive. If this mechanism is opened and closed with the underwater valve of a big flow, it becomes possible to obtain the big electric power.

Abstract: As for the gears, this invention makes the transmission angle error and the backlash very small, and reduces vibration and mechanical sound. If form of the teeth in gears are made into the circle, at the angle which the peak of a tooth top and the peak of a tooth bottom overlap, the backlash of the gears will be made to zero. As for the other mesh angle, the correct degree of transmission angle is included in the range of the backlash. If it sets it as 1 cycle to become mesh of the same condition, as for one half of cycles, it will be in the condition which the tooth top and the tooth bottom replaced, and will become the same mesh. If the slice of the gears of the circle-tooth is made as the helical gear by the detailed lamination, the mesh from which the phase shifted exists in that pitch point, and the action of the gears are limited at a zero-backlash-part.

Abstract: A bi-directional converter between pressure and rotational force includes engaging rotation members that continue to rotate while being adjacent to each other without collision; the rotation members and an outer wall form an enclosed space; rotation shafts of the rotation members are mutually engaged by gear wheels; the rotation members are synchronized and rotate in opposite directions; the rotation members are rotated by a volume change of the enclosed space by application of pressure from outside; and the volume of the enclosed space is changed by rotational force to generate a pressure difference. The bi-directional converter includes an open-close mechanism opening and closing supply exhaust paths inside the rotation member and disposed to the rotation shaft or the outer wall according to a rotation angle.

Abstract: A bi-directional converter between pressure and rotational force includes engaging rotation members that continue to rotate while being adjacent to each other without collision; the rotation members and an outer wall form an enclosed space; rotation shafts of the rotation members are mutually engaged by gear wheels; the rotation members are synchronized and rotate in opposite directions; the rotation members are rotated by a volume change of the enclosed space by application of pressure from outside; and the volume of the enclosed space is changed by rotational force to generate a pressure difference. The bi-directional converter includes an open-close mechanism opening and closing supply exhaust paths inside the rotation member and disposed to the rotation shaft or the outer wall according to a rotation angle.