Movement No. 154 converts continuous circular motion into alternating rectilinear motion using studs on a rotating disk, a bell-crank lever, and a gravity-return weighted cord. The rotating disk carries studs on its face. As the disk turns, each stud sequentially contacts one arm of a bell-crank lever, pushing it and causing the bell-crank to pivot about its fixed fulcrum. The other arm of the bell-crank is connected to a cord that passes over a pulley and carries a weight at its end. When a stud pushes the first arm of the bell-crank, the second arm pulls the cord upward — lifting the weight and moving the attached rod or mechanism in one direction. When the stud passes and disengages, the hanging weight pulls the cord back down, swinging the bell-crank in the opposite direction and returning the rod to its original position. This elegant weight-return mechanism ensures reliable, automatic reversal without springs, using gravity as the restoring force for each cycle of the rotating disk.
154. Circular motion into alternating rectilinear motion, by the action of the studs on the rotary disk upon one end of the bell-crank, the other end of which has attached to it a weighted cord passing over a pulley.