Another kind of chain and pulley

Only the input is driven; every other part of this model moves by physics (MuJoCo), and its ratios are measured. Run it live, change its parameters, or switch the friction off to see the output stop.

Modelled as

The plate's ladder chain: two side bars a link (pitch 2.4, radius 0.3), joined at every joint by a round rung, each link hinged to the next on its rung. The pulley is a 10-sided polygon: two rims carry the side bars, and between the rims each face has a wedge tooth that enters the opening between two rungs and pushes the rung ahead. The right-hand end carries a 0.4 kg weight in vertical guides and the left end hangs free (gravity on). Only the pulley is driven (4 rpm, counter-clockwise).

Measured

The weight rises 0.0384 m per radian of the pulley (expect 0.0382, the pitch radius of the 10-sided chain path), r-squared 1.0000. Max penetration 0.02 mm.

Notes

The plate gives no sizes. Its cheek is in front of the chain; here it is behind, so the teeth can be seen.

Film (MP4) · Still (PNG) · Spec (YAML) · Model (MJCF)