Ben and Jerry are two new characters for this third automaton, young competitive brothers going head to head at the Gymnasium. A simple set of cams to drive the right arm into a punch, with a wire attached to the forearm to move it straight to the Punchball.
Each brother taking it, in turn, to hit the Punchball, with the timing being controlled by swivel plate mounted in the centre of the camshaft.
Construction is straightforward, guided by the drawings shown here. The motion is geared down three to one to slow the motions as they seemed all a little quick when driven directly.
For more information on this and other projects go to https://www.3dprinterclocks.com/page26.html
0.14 mm with medium infill.