Patent ID: 6937122

Claim:
An electric starter for an internal combustion engine comprising; an electric motor having a housing and a rotatable armature shaft extending therethrough, the shaft having a helical spine portion; a pinion gear mounted for selectively engaging a ring gear of the engine; a clutch assembly for transmitting torque between the shaft and the pinion gear, the clutch assembly having a driving part and a driven part, the driving part having an internal helical spline portion engaging the helical spline portion of the shaft whereby relative rotary movement between the shaft and the driving part creates axial movement of the clutch assembly along the shaft, and the pinion gear being fixed for rotation with the driven part; and a solenoid for holding the pinion gear in engagement with the ring gear; wherein the solenoid has a toroidal coil and a tubular plunger located about the shaft between the motor housing and clutch assembly, the tubular plunger having a radially extending flange at a first end which is arranged to be attracted towards the coil and having a second end which bears against the driving part of the clutch assembly.