US Patent 7300323 Linear actuator for flapping hydrofoil

A linear actuator is provided that converts linear motion to oscillatory motion. The linear actuator includes flats, a hinge, and linear actuators. A hydrofoil is mountable on a spindle attached to the hinge. In operation, a linear push direction by the linear actuator drive causes the hydrofoil to rotate in an oscillating manner. A linear push by another linear actuator drive reverses the oscillation directions of the hydrofoil. The flats are preferably made of flexible strip metal to easily transmit motion to the spindle. The hydrofoil and spindle combine to a slot for smooth transmission of linear to oscillatory motion.