Method of and apparatus for stretching a metal strip

摘要

A metal strip is spanned over a plurality of rollers carried on a pair of frames. A single heavy-duty drive motor rotates a common drive shaft that is connected via bevel gearing to the sun gears of a plurality of planetary-gear assemblies each having its planet carrier connected to the respective roller. The ring gear of one of these assemblies is fixed whereas the ring gears of all of the other assemblies are connected to respective compensating motors. A torque sensor at the output of each compensating motor generates an actual value signal indicating the amount of torque being applied by that motor to the respective ring gear. The comparator compares this actual-value signal with a set point coming from a single set-point generator and varies the motor speed in accordance with the difference between these two signals.