Patent ID: 8628269

Claim:
A drive coupling for transferring a rotational force, comprising: a first member having an end portion; a second member having an end portion that is engageable with the first member; a helical, cross-sectionally petaline recess defined in the end portion of the first member, the petaline recess having a recess axis and including a plurality of interconnected petal shaped recess portions disposed readially about the recess axis, each petal shaped recess portion including substantially convex, arcuate sides interconnecting at a petal tip with the sides of adjacent recess portions meeting at a common edge; a projection disposed on the end portion of the second member that is coaxially and rotationally engageable with the petaline recess, the projection including a base cylinder, said base cylinder comprising a plurality of helical teeth extending radially about a projection axis, wherein the teeth are defined by substantially convex, arcuate sides, the teeth further including a tip having flattened edges; wherein one of the first or second members is a driving member and the other is a driven member such that rotation of the driving member causes engagement between each tooth and a respective petaline side whereby the recess axis and the projection axis become coaxial and the driven member is driven, and wherein a radius of each tooth as measured from a center of the projection to the tip of the tooth is substantially less than the radius of each petal tip as measured from a center of the recess such that the position of the center of the projection relative to the center of the recess is radially adjustable.