Patent ID: 8915112

Claim:
A coil spring end forming method comprising: placing a cylindrical coil-shaped semi-formed spring that tends toward formation of a pigtail portion at one end thereof on a pair of horizontally disposed parallel rollers; pushing the semi-formed spring using a pusher toward a clamp portion provided adjacent to one end of the parallel rollers while the semi-formed spring is rotated in a winding direction by the parallel rollers; bringing the one end of the semi-formed spring into contact with a stopper provided at the clamp portion between axes of the parallel rollers; positioning an axis of a mandrel between the axes of the parallel rollers and an axis of the semi-formed spring; holding the one end of the semi-formed spring by a clamp jig provided in the clamp portion and the mandrel inside a triangle formed by the axes of the parallel rollers and the semi-formed spring; and rotating the clamp portion around the axis of the mandrel along the winding direction of the semi-formed spring and winding the one end of the semi-formed spring around the mandrel to form the pigtail portion, wherein the axis of the mandrel is offset from the axis of the semi-formed spring and stays inside the triangle during the formation of the pigtail portion.