Robert Bosch

Dieter Grozinger

Heribert Schramm

Steffen Wunsch

Rainer Schilling

Erich Vogel

An electric machine, particularly a miniature electric motor, includes a stator structure provided with at least one pair of main poles and at least one pair of auxiliary poles, the auxiliary poles alternating with the main poles. Each main pole is comprised of a main pole core and a main pole winding on the respective main pole core. Each auxiliary pole is comprised of an auxiliary pole core and an auxiliary pole winding on the respective auxiliary pole core. A holding arrangement holds the auxiliary pole windings in place on the auxiliary pole cores and includes holding fingers extending in direction parallel to the axis of the stator structure into the intermediate spaces between adjoining main and auxiliary pole windings, and furthermore includes a holding ring to which the holding fingers are connected at one end, the holding ring lying against one axial side of the stator structure.

Arrangement for holding windings on pole cores

A housing accommodates a motor and a tool shaft which is to be driven by the same. A gear drive is interposed between the motor and the tool shaft and transmits power from the former to the latter. The gear drive has at least two gear sets providing different gear ratios, and an intermediate shaft. An axial safety coupling is associated with each of the gear sets and provided on the intermediate shaft to be rotatable with the same. Each safety coupling includes axially extending projections which are distributed about the axis of rotation of the intermediate shaft and which have circumferentially defined flanks. Each safety coupling has a diameter and a flank inclination at least one of which is accommodated to the torque generated by the gear ratio associated with the safety coupling. A biasing spring urges the projections of the safety couplings into engagement with one another.

Variable-speed drill

A driven output shaft is mounted in a housing and has freedom of limited axial displacement between a first and a second position. A biasing spring permanently biases the output shaft to the first position. An impact member surrounds the output shaft and has a plurality of angularly spaced first axial projections which interdigitate with angularly spaced second axial projections provided on a disk member axially fixed on and turnably surrounding the output shaft. A retaining arrangement is provided in the housing and is engageable with the disk member to prevent rotation of the same when an axial force is exerted upon the output shaft counter to the action of the biasing spring, causing axial displacement of the output shaft to the second position thereof, and engagement of the disk member with the retaining arrangement.

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Echterdingen, Germany

Dieter Grozinger