| 198 / | HD | CONVEYORS: POWER-DRIVEN | 
| 523 | DF | CONVEYOR SYSTEM HAVING A GRAVITY CONVEYOR SECTION {11} | 
| 540 | DF | .~ Gravity discharge material holder is source of supply, discharging by gravity to power-driven section {6} | 
| 543 | DF | .~.~ With at least one more successive power-driven section {2} | 
| 544 |  | .~.~.~ Of the apron belt type |