Abstract: An electrical commutator machine which serves to actuate units is proposed. The commutator machine comprises a ring-like carrying plate, which surrounds the axis of rotation of the commutator, for tubular guide casings which are made of metal, have a square cross section, are permanently connected to said carrying plate and in which brushes belonging to the commutation device are guided along the longitudinal axis of the tube and are placed under load on a contact face of the commutator. A particularly simple and advantageous structure of the commutator machine is produced if, in order to secure the casing on the carrying plate, at least two tongues which are upright with respect to the wall plane are arranged on one of the casing walls, to which tongues there are assigned insertion slits which are located in the one end of the carrying plate and detain the tongues.

Abstract: A process for producing sintered parts with high wear resistance and good dynamic strength properties from formed bodies, which have been pressed as green parts from a completely-alloyed air-hardened heat-treatment steel powder with a carbon content of at least 0.3% added in the form of graphite. The process includes sintering the parts under protective gas at a sintering temperature of at least 1000.degree. C. and subsequent cooling. The sintered parts are cooled immediately after sintering from the sintering temperature to a first holding temperature in the range of Ar.sub.3 to a maximum of 150.degree. C. above Ar.sub.3 and are held for a first holding period of 5 to 25 minutes at this temperature (austenitizing phase). Immediately after this, the sintered parts are cooled in accelerated fashion to a second holding temperature by convective gas cooling and are held at this temperature for a second holding period.