A valve motion for working steam expansively
A valve motion for working steam expansively. The series of cams of varying throw are movable lengthwise of the shaft so that either may be made to act upon the lever to which the valve-rod is connected. A greater or less movement of the valve is produced, according as a cam of greater or less throw is opposite the lever.
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
- A shaft (the one driven joint, 30 rev/min) carries three eccentric cams of throw 2.2, 1.5 and 0.8 cm side by side, joined by ramps, and is slid lengthwise by the hand (a spring-held carriage, moved 3 cm at 7 s and again at 14 s) so that each cam in turn comes under the finger of the lever. The lever rests on the cam by its own weight and, by a link pinned 12 cm from its pivot, works the valve-rod in its guides, so the stroke follows the throw of the cam in action: gen150.py.
- Measured
- Valve-rod follows the shaft with slopes -0.0143/+0.0140, -0.0097/+0.0096 and -0.0051/+0.0051 m per rad (r2 0.994 to 0.999) for the three cams, strokes 2.94, 2.0 and 1.07 cm. Penetration 0.05 mm after the first second.
- Notes
- The cams stand in order of falling throw, so the finger steps down from one to the next by a ramp; the hand schedule moves only the spring that holds the shaft, as a hand would, and the shaft is slid by that spring against its damping.
Film (MP4) · GIF · Still (PNG) · Spec (YAML) · Model (MJCF)
