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Ross yoke a = h = 20 for two parallel syringes
What shape and size is a Ross yoke that gives 90° between two pistons? · Hardware · basis: Linkage solved over a full turn (720 steps) in the generator: crank e 6, yoke a = h = 20, rocking link 40 from a pivot at (−40, 20), con-rods 60
Long Earth Society build part. The parallel-cylinder alpha, solved. The engines
Exact dimensions. Every file is drawn at true size with no printing tolerance. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your printer's or process's clearance before making the part. Mating features
- sizes
- 8 in table
Notes
- The triangular rocker of the Ross yoke alpha. Its half-width equals its height (a = h = 20), which puts the two top corners a quarter-turn apart: piston phase 90.0°, strokes 17.0 and 17.2 mm.
- Bottom vertex: a Ø3 hole (fit: run) that rides on the crank pin. Top corners at ±20: Ø3 holes (fit: press) for the con-rod pins. Between them, the top-middle Ø3 hole (press) for the rocking-link pin.
- Outline 52 × 32 × 6 with 3 mm corner radii.
Sizes
| parameter | value |
|---|---|
| a (half-width) | 20 |
| h (height) | 20 |
| outline | 52 × 32 × 6 |
| crank-pin hole | Ø3 run |
| con-rod and rocking pins | 3 × Ø3 press |
| phase | 90.0° |
| strokes | 17.0 / 17.2 |
| max con-rod angle | 0.91° |
Mating features
Drawn at the exact size. Open press, slide, run and socket features by your process's clearance; leave designed gaps and clamp fits as drawn.
| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| yoke corner and top pins | Ø3 | Ø3 pins | press | ross-yoke-* |
| yoke crank-pin hole | Ø3 | crank pin (turns in it) | run | ross-yoke-* |
Where the files are
Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.
| Wikipedia | Ross yoke | web | CC BY-SA 4.0 (text) |
| Long Earth Society | Engine builds | web, video | LES site |
Free files
★ Free files 1 parts. Generated by Xem Studio from the standard; threads are plain cylinders at major diameter. CC BY 4.0. index.json
| ross-yoke-a20-h20 | Ross yoke a = h = 20: Ø3 running hole on the crank pin at the bottom vertex, Ø3 press holes for the two con-rod pins at ±20 and the rocking pin between them | STEP · STL |
Plain text: sheet.txt · JSON: /api/geometry?object=ross-yoke
How it fits
Connects to
Ross yoke crank disc Ø24, 6 mm throwbottom vertex rides the disc's Ø3 crank pin
Con-rods with Ø3 pin ends, 45 and 60 mm, 8 × 5conrod-60 on the ±20 corner pins
Ross yoke rocking link, 40 mmtop-middle pin to the rocking linkAlso needed
Crankshafts Ø3, Ø5 and Ø8 with full-length D-flatØ3 × 12 and Ø3 × 20 pins, spacers
Metric shafts Ø3 to Ø10 with D-flats and clip…3 mm collars on the free pin endsIn these build lists
Ross yoke alpha, two parallel 10 mL syringesTwo 10 mL syringe barrels side by side on a Ross yoke: a = h gives 90° between t…You might also need
Questions
What ratio gives 90° on a Ross yoke?
Half-width equal to height, a = h. Here a = h = 20 with a 6 mm crank and 40 mm rocking link gives 90.0°, checked over a full turn.
Why are Ross yoke con-rods almost vertical?
The yoke's top corners move nearly straight up and down; the 60 mm rods stay within 0.91° of vertical, so the pistons see almost no side load.