Patent ID: 7438681

Claim:
An electronic variable stroke device comprising: a base portion containing a motor and power source for rotating a screw shaft alternately in opposite rotational directions, an upper portion extending longitudinally from the base portion and having a flexible cover layer connected to a proximal end of said base portion and extending around a tip end of the upper portion, wherein the rotary-driven screw shaft has a length extending longitudinally into the upper portion to said tip end thereof and is provided with screw threading thereon, and a screw-thread traveler or follower having a bulging contour projecting against the flexible cover layer so as to create a bulging contour on an external side of the cover layer, said screw-threaded follower being positioned within the upper portion and engaged with the screw shaft threading in order to drive the bulging contour formed on the external side of the cover layer in reciprocating longitudinal motion; and further comprising electronic controls provided in said base portion for controlling rotation of the screw shaft to vary the length, speed, and frequency of the bulging contour on the external side of the cover layer in variable-stroke reciprocating longitudinal motions.