| 摘要 |
The invention relates to a step drive assembly which includes a rotatable operating unit for operating a tool or knife or the like. The assembly has a change-over clutch for selectively connecting the operating unit to a continuously running motor or a brake. Control apparatus for the assembly includes a disk rotatable with the operating unit having teeth and spaces therebetween forming zones and a sensor unit for scanning the zones and outputting a pulse train. An evaluating circuit responsive to the pulse train outputs a positioned stop signal and an overload stop signal to effect a braking operation. |
