Fluid-responsive oscillation power generation method and apparatus

Power generation apparatus comprising

• a wing-shaped blade having opposite sides, opposite ends and leading and trailing edges extending between said ends;
• a blade shaft extending along an axis in the blade that is in close parallel relation to the leading edge of the blade and fixed to move with the blade;
• supports for supporting the blade shaft so that when the blade is positioned in a moving fluid stream with said leading edge facing upstream the blade can oscillate about said axis between first and second extreme positions on opposite sides of a neutral position;
• lift differential producing means in the blade for producing a lift differential at the opposite sides of the blade in the presence of the moving fluid stream;
• means for switching the lift differential producing means so that one blade side or the other produces the greater lift in the presence of the moving fluid stream;
• coordinating means for coordinating the switching means with the swinging of the blade so that the switching occurs only at each extreme position of the blade to produce a blade lift which urges the blade toward the other extreme position so that the blade oscillates between said extreme positions in the presence of the moving fluid stream;
• a power takeoff device which reciprocates in response to the oscillation of the blade so that the apparatus can drive an external machine;
• first and second fluid boundaries located close to said first and second extreme positions of the blade and extending at an acute angle to the trailing edge of the blade when the blade is in said first and second extreme positions, said supports being positioned on opposite sides of a water stream so that said axis extends substantially horizontally in said water stream with said boundaries being located above and below said axis;
• an inflatable dam extending between said sides of the stream downstream from the blade, and
• means for selectively inflating and deflating the dam.

Power generation apparatus comprising

• a wing-shaped blade having opposite sides, opposite ends and leading and trailing edges extending between said ends;
• a blade shaft extending along an axis in the blade that is in close parallel relation to the leading edge of the blade and fixed to move with the blade;
• supports for supporting the blade shaft so that when the blade is positioned in a moving fluid stream with said leading edge facing upstream the blade can oscillate about said axis between first and second extreme positions on opposite sides of a neutral position;
• lift differential producing means in the blade for producing a lift differential at the opposite sides of the blade in the presence of the moving fluid stream;
• means for switching the lift differential producing means so that one blade side or the other produces the greater lift in the presence of the moving fluid stream;
• coordinating means for coordinating the switching means with the swinging of the blade so that the switching occurs only at each extreme position of the blade to produce a blade lift which urges the blade toward the other extreme position so that the blade oscillates between said extreme positions in the presence of the moving fluid stream;
• a power takeoff device which reciprocates in response to the oscillation of the blade so that the apparatus can drive an external machine;
• and
• wherein the lift differential producing means include holes in the sides of the blade and an air pressure source that can increase or decrease the air pressure at the holes in one side of the blade as compared to the air pressure at the holes in the other side of the blade and the coordinating means include fluid control means for reversing said air pressures.

Power generation apparatus comprising

• a wing-shaped blade having opposite sides, opposite ends and leading and trailing edges extending between said ends;
• a blade shaft extending along an axis in the blade that is in close parallel relation to the leading edge of the blade and fixed to move with the blade;
• supports for supporting the blade shaft so that when the blade is positioned in a moving fluid stream with said leading edge facing upstream the blade can oscillate about said axis between first and second extreme positions on opposite sides of a neutral position;
• lift differential producing means in the blade for producing a lift differential at the opposite sides of the blade in the presence of the moving fluid stream;
• means for switching the lift differential producing means so that one blade side or the other produces the greater lift in the presence of the moving fluid stream;
• coordinating means for coordinating the switching means with the swinging of the blade so that the switching occurs only at each extreme position of the blade to produce a blade lift which urges the blade toward the other extreme position so that the blade oscillates between said extreme positions in the presence of the moving fluid stream;
• a power takeoff device which reciprocates in response to the oscillation of the blade so that the apparatus can drive an external machine;
• first and second fluid boundaries located close to said first and second extreme positions of the blade and extending at an acute angle to the trailing edge of the blade when the blade is in said first and second extreme positions,
• wherein said supports are located in a housing so that said axis extends substantially vertically in the housing, said boundaries being housing structure laterally offset on opposite sides of said axis, and
• further including a tower having a base, a base support and a top, and securing means for securing the housing at the top of the tower.

Power generation apparatus comprising

• a wing-shaped blade having opposite sides, opposite ends and leading and trailing edges extending between said ends;
• a blade shaft extending along an axis in the blade that is in close parallel relation to the leading edge of the blade and fixed to move with the blade;
• supports for supporting the blade shaft so that when the blade is positioned in a moving fluid stream with said leading edge facing upstream the blade can oscillate about said axis between first and second extreme positions on opposite sides of a neutral position;
• lift differential producing means in the blade for producing a lift differential at the opposite sides of the blade in the presence of the moving fluid stream;
• means for switching the lift differential producing means so that one blade side or the other produces the greater lift in the presence of the moving fluid stream;
• coordinating means for coordinating the switching means with the swinging of the blade so that the switching occurs only at each extreme position of the blade to produce a blade lift which urges the blade toward the other extreme position so that the blade oscillates between said extreme positions in the presence of the moving fluid stream;
• a power takeoff device which reciprocates in response to the oscillation of the blade so that the apparatus can drive an external machine;
• a second power generation apparatus similar to said first-mentioned apparatus, and
• coupling means coupling together the two power takeoff devices of said first-mentioned and said second power generation apparatus so that said two power takeoff devices reciprocate 180° out of phase.

A method for generating power comprising the steps of

• forming a wing-shaped blade having opposite sides, opposite ends, leading and trailing edges extending between said ends and a shaft fixed to the blade and extending parallel to said leading edge;
• rotatably supporting the shaft so that the blade is exposed to a moving fluid stream with said leading edge facing upstream and can oscillate about an axis between first and second extreme angular positions on opposite sides of a neutral position;
• changing the aerodynamic characteristics of the blade in coordination with the swinging motion of the blade so that just after the blade swings to said first extreme position, the blade side facing away from the first extreme position produces more lift than the blade side facing said first extreme position, and just after the blade swings to said second extreme position, the blade side facing away from the second extreme position produces more lift than the blade side facing the second extreme position, so that the blade oscillates between said extreme positions in the presence of the moving fluid stream;
• causing a substantial blocking of the flow of the moving fluid stream on the blade side facing each extreme position and a rapid increase in said flow on the opposite blade side when the blade reaches each extreme position to impel the blade toward the other extreme position, and
• providing a power takeoff device which reciprocates in response to the oscillation of the blade to drive an external machine.

Power generation apparatus comprising

• a wing-shaped blade having opposite sides, opposite ends and leading and trailing edges extending between said ends;
• supports for supporting the blade in a moving fluid stream with its leading edge facing upstream so that the blade can oscillate about an axis extending along the blade between first and second extreme positions on opposite sides of a neutral position;
• an aerodynamic device in the blade for producing a lift differential at the opposite sides of the blade in the presence of the moving fluid stream, said device being reversible so that one blade side or the other produces the greater lift;
• a mechanism for coordinating the device to the swinging motion of the blade so that just after the blade swings to the first extreme position, the blade side facing away from the first extreme position produces the greater lift and just after the blade swings to the second extreme position, the blade side facing away from the second extreme position produces the greater lift, said mechanism reversing said device to reverse the lift differential only at the extreme positions of the blade so that the blade oscillates between said extreme positions in the presence of the moving fluid stream;
• first and second fluid boundaries located adjacent to respective first and second extreme positions of the blade close to trailing edge of the blade when the blade is in said first and second extreme positions for simultaneously causing a substantial blocking of the flow of the moving fluid stream on the blade side facing each extreme position and a rapid increase in said flow on the opposite blade side when the blade reaches each extreme position to impel the blade toward the other extreme position, and
• a power takeoff device which reciprocates in response to the blade oscillation for driving an external machine.