| 74 / | HD | MACHINE ELEMENT OR MECHANISM | 
| 828 | DF | ALTERNATING-MOTION DRIVEN DEVICE WITH MEANS DURING OPERATION TO ADJUST STROKE {2} | 
| 831 | DF | .~ Stroke adjustable to zero and/or reversible in phasing {6} | 
| 833 |  | .~.~ Device driven from selected points on oscillating link |