Patent ID: 8573131

Claim:
A cam apparatus for positioning a payload assembly traveling along a track, comprising a number of force imparting elements positioned proximate to the track; a follower mechanism linked to the payload assembly comprising force transmission elements interacting with each of the force imparting elements when the payload assembly travels along the track; and a mechanical orientation assembly linked to the payload assembly and the follower mechanism, wherein the mechanical orientation assembly comprises mechanical means between the follower mechanism and the payload assembly operating to provide a resultant rotational movement of the payload assembly that is greater than or less than the rotation of the follower mechanism relative to the rotational axis of the payload assembly, wherein the force imparting elements and the force transmission elements are arranged in the cam apparatus such that rotational motion is produced in the follower mechanism to selectively position the payload assembly about its rotational axis with the payload assembly position being related to a relative linear displacement between the follower mechanism and the force imparting elements, wherein the cam apparatus includes six force imparting elements positioned in three pairs in three planes orthogonal from the rotational axis of the payload assembly and offset from each other, and wherein the force imparting elements of each of the pairs are spaced apart on opposite sides of the rotational axis such that the force imparting elements of each of the pairs concurrently contact the force transmission elements.