Rotary motion of shaft from treadle by means of an endless band…
Rotary motion of shaft from treadle by means of an endless band running from a roller on the treadle to an eccentric on the shaft.
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
- Brown's elevation, gravity on. The shaft runs through a 7 cm eccentric (its centre 3.5 cm from the shaft) and carries a flywheel behind it (Brown's dotted circle). An endless band runs round the eccentric and round a roller on the treadle below, which is pivoted at the right. The band is a stiff loop free to slide and turn in the plane, touching only the eccentric and the roller. The one driven input is the foot on the treadle (driver feet, timed by the shaft): it presses the treadle down, never lifts it, through the half-turn in which the eccentric goes down, and lets it rise for the other half while the eccentric lifts band, roller and treadle; the flywheel carries the shaft over both dead points. The shaft works against a light viscous load.
- Measured
- Started at rest with the eccentric level with the shaft, the shaft turns one way only (back-run under 0.05 rad), half a turn to each down or up stroke of the treadle (one turn per down-and-up), and keeps turning above 6 rad/s on average over both dead points. Band, eccentric and roller do not penetrate (under 1.5 mm). With the band taken off, the foot works the treadle loose and the shaft stands.
- Notes
- The foot is an operator who times the stroke from the shaft's position (press-only, half a turn on, half off) rather than a free-running treadle stroke; the band is a stiff loop, not a flexible strap; the flywheel, the shaft's bearing and the treadle's stand are drawn in.
Film (MP4) · Still (PNG) · Spec (YAML) · Model (MJCF)
