Coarse and fine drives for an objective

摘要

The invention is directed to an arrangement for displacing the parts of an objective with at least one adjusting ring 6. A fine adjusting ring 40 is also provided and there is no switchover device which must be actuated by the operator. The fine adjusting ring 40 is at standstill when it is not actively rotated by the operator. A coarse adjusting ring 6 is rotatably journalled in the housing 10 of an objective. A transmission or gearing for suitably fine adjusting this coarse adjusting ring 6 includes a sun gear wheel 1 mounted fixedly on the objective housing 10, a fine adjusting ring 40 which includes a shaft pin 4 on which planetary gear wheels 2 are journalled and an output gear wheel 3 rotatably mounted on the coarse adjusting ring 6 via a slip clutch 5.