An apparatus for converting rotational movement of a rotary member to harmonic linear motion for moving an article transfer apparatus between a first position and a second position. The apparatus provides a follower pivotally connected to the extending end of the rotary member, and a planar support plate having a slotted aperture for receiving the follower of the rotary member. A pair of opposing low friction planar guides slidingly support the support plate of the article transfer apparatus for movement in a predetermined plane. When the rotary member rotates, the follower moves along the slotted aperture of the support plate, and the support plate slides along the planar guides thus imparting linear motion to the article transfer apparatus. When the rotary member is rotated at a substantially constant rotary speed, the linear motion translated to the article transfer apparatus is best described as harmonic motion. The article transfer apparatus may provide a conveyor for transferring an article or workpiece along a predetermined path of travel. The conveyor may have its own independent power means for powering the conveyor.