Abstract: A driving force member for receiving rotational driving force includes a base portion, a projection portion including three planar surfaces, the three planar surfaces arranged such that if they were extended and viewed in cross section perpendicular to the axis of the projection, they would intersect at 120 degrees in the form of an equilateral triangle, the three planar surfaces corresponding to a partial length of each side of the triangle respectively and offset from the center of each respective side of the triangle, and three joining portions joining each of the three planar surfaces, the three joining portions lying entirely within the equilateral triangle.

Abstract: A driving force member for receiving rotational driving force includes a base portion, a projection portion including three planar surfaces, the three planar surfaces arranged such that if they were extended and viewed in cross section perpendicular to the axis of the projection, they would intersect at 120 degrees in the form of an equilateral triangle, the three planar surfaces corresponding to a partial length of each side of the triangle respectively and offset from the center of each respective side of the triangle, and three joining portions joining each of the three planar surfaces, the three joining portions lying entirely within the equilateral triangle.

Abstract: A resilient driving force member 10 having at least one helical spring 16, each helical spring 16 having an support member 14 connected to one end thereof and an engaging portion 20 connected to the other end, the engaging portion extending further from an axis X central to the turns of the helical spring 16 than the turns, where the engaging portion 20 of the resilient driving force member 10 is adapted to engage a corner or side of another driving force member of substantially similar size having either a twisted or non-twisted recess such that, when so engaged, rotational driving force can be transferred from one driving force member to the other.