COMMUTATOR MOTOR AND IMPROVED BRUSH CONSTRUCTION FOR USE IN PORTABLE MACHINE TOOLS

摘要

A commutator motor specifically designed for incorporation into portable machine tools such as a hand drill includes a stator winding in a machine housing, and a rotor winding including a rotor shaft with a commutator ring journalled in the housing. Electrical connection between the commutator and current supply is ensured by multiple pairs of diametrically opposed carbon brushes of opposite polarity, the brushes being supported in the machine housing such that each respective pair of brushes can be separately brought into contact with the commutator by a setting means capable of engaging the respective pairs of brushes. Various holder configurations for supporting the brushes include sliding cams.