| 摘要 |
PCT No. PCT/EP85/00160 Sec. 371 Date Dec. 5, 1985 Sec. 102(e) Date Dec. 5, 1985 PCT Filed Apr. 9, 1985 PCT Pub. No. WO85/04548 PCT Pub. Date Oct. 24, 1985.In a cutting head for an electric-motor-driven filament-type cutter the automatic adjustment of the length of the filament is effected in that intermittently a rotational movement occurs between a filament spool (36) and a sleeve (24) mounting said spool for axial displacement. The sleeve (24) is provided on the outside with locking cams and the filament spool on the inside with cams cooperating therewith. The sleeve (24) can be pushed in by hand against spring pressure to cancel the intermittent locking. For automatic filament adjustment a centrifugal adjustment is provided. For this purpose at least two radial ball slots (40) are provided between the housing portion (14) and a radial extension (48) of the sleeve (24) and in the ball slots balls (44) are guided which are adapted to be urged outwardly by centrifugal force. Since the height of the ball slot varies over an inclined plane (42), when the balls (44) move radially outwardly a spreading of the two parts (48, 14) takes place so that intermittent unlocking results. The individual rotational angle portions are limited by lower and upper cams which cooperate with a counter cam which is controlled by the displacement movement and cooperates alternately with the one or other cam, the sectionwise or intermittent angular displacement taking place by repeated switching on and off of the motor.
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