Patent ID: 8308631

Claim:
An electronic variable stroke device comprising: a body containing a motor and power source for rotating a screw shaft alternately in opposite rotational directions, wherein the rotary-driven screw shaft has a length extending along a longitudinal axis of said body and is provided with screw threading thereon, and a screw-thread traveler or follower arranged for reciprocating motion along the longitudinal axis of said body and engaged with the screw shaft threading in order to drive it in reciprocating longitudinal motions, said traveler or follower having an annular shape with an aperture therethrough which is driven in reciprocating longitudinal motions by engagement of said traveler or follower with said screw shaft; and further comprising electronic controls provided in said body for controlling rotation of the screw shaft to vary the length, speed, and frequency of the traveler or follower in variable-stroke reciprocating longitudinal motions.