| 74 / | HD | MACHINE ELEMENT OR MECHANISM |
| 640 | DF | GEARING {31} |
| 665 R | DF | .~ Plural power paths to and/or from gearing {10} |
| 665 F | ![]() | .~.~ Single drive plural driven {4} |
| 665 G | DF | .~.~.~> Parallel {5} |
| 665 H | DF | .~.~.~> Nonparallel |
| 665 S | DF | .~.~.~> Aligned {1} |
| 665 K | DF | .~.~.~> Concentric |