198 / | HD | CONVEYORS: POWER-DRIVEN |
570 | DF | CONVEYING SYSTEM HAVING PLURAL POWER-DRIVEN CONVEYING SECTIONS {18} |
571 | DF | .~ With condition responsive control of a section {1} |
572 | DF | .~.~ By means responsive to presence or condition of load {1} |
573 | .~.~.~ By overload sensing |