US Patent 7174874 Recoil starter

A coil starter formed so that the rotation of a rope reel is transmitted to a cam member via a coil spring-like damper spring both ends of which are engaged with the rope reel and cam member respectively, wherein the rope reel or cam member is provided with a boss portion the length of which is substantially equal to that of a wound portion of the damper spring, the inner circumferential side of substantially the whole length of the damper spring being supported on the boss portion, the wound portion of substantially the whole length of the damper spring being thereby wound uniformly and tightly around the outer circumferential surface of the boss portion when the damper spring is elastically deformed due to the engine starting resistance.