| 摘要 |
PCT No. PCT/DE91/00074 Sec. 371 Date Nov. 23, 1992 Sec. 102(e) Date Nov. 23, 1992 PCT Filed Jan. 23, 1991 PCT Pub. No. WO91/15050 PCT Pub. Date Oct. 3, 1991.A short-circuiting and brush-lifting device comprises a rotatable actuating ring having with brush-actuating rods levers cause the brushes of the motor to lift up via the rotating actuating after the slip rings have been short-circuited as a result of the axial displacement of a short-circuiting ring. To make the device wear-resistant and insensitive to contamination, the actuating ring supports three rollers, with which it abuts in the starting position on the spring-loaded short-circuiting ring. The actuating ring is guided exactly in parallel by three axial guide rods, which are disposed perpendicularly to the brush-actuating rods. The configuration of all articulated joints of these rods is adjusted so as to allow the points of maximum excursion of the deflection of the articulated joint of the axial guide rods and the brush-actuating rods are exhibited at staggered times. In this manner the brush-actuating rod runs through its point of maximum excursion first and, after that, the axial rod runs through its point of maximum excursion. The clearance between the short-circuit contacts of the short-circuiting ring and the short-circuit contacts of the slip rings is smaller in the starting position is than the axial movement of the actuating ring during the short-circuiting operation, so that the brushes do not lift up until after the short-circuiting operation has taken place.
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