Movement No. 153 converts continuous circular motion of a rotating disk into alternating rectilinear motion of a horizontal bar, using a combination of studs and a bell-crank lever. The rotating disk carries multiple studs on its face. As the disk turns, one stud strikes a projection on the underside of the horizontal bar and pushes it in one direction. For the return stroke, the next stud on the disk contacts one arm of a bell-crank (elbow-lever); the other arm of the bell-crank then swings and strikes a separate stud on the front of the horizontal bar, pushing it back in the opposite direction. This alternating push-and-return action, driven entirely by the sequence of studs and the bell-crank, produces a smooth back-and-forth motion of the bar from a single continuously rotating disk. The mechanism is compact and mechanically direct, requiring no springs or cams for reversal — the geometry of the stud sequence and bell-crank handles all direction switching automatically.
153. Circular motion into alternating rectilinear motion. The studs on the rotating disk strike the projection on the under side of the horizontal bar, moving it one direction. The return motion is given by means of the bell-crank or elbow-lever, one arm of which is operated upon by the next stud, and the other strikes the stud on the front of the horizontal bar.