Double insulated starter motor

Abstract

The invention pertains to electric starter motors for internal combustion engines, particularly motors used with smaller engines such as employed to power lawn mowers, snow blowers, lawn tractors and similar equipment. The motor housing is formed of a dielectric material as to be doubly electrically insulated for protection against electrical shock, the motor casing features simplify assembly of the field coil within the casing, and the motor armature shaft portion and starter pinion shaft portion are formed as two components, rather than the usual one piece, permitting separate heat treatment and eliminating the need for shaft straightening after hardening as required when the armature and pinion shaft are homogeneously formed. Improved frictional engagement between the starter pinion and starter drive nut is achieved by the use of a low friction slip ring, and the operating switch for the starter is encompassed within a dielectric, weatherproof receptacle which may be readily assembled and is tamperproof to protect against shock even under high moisture conditions.