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Cone pulleys (speed cones) for gradually varied speed

How do cone pulleys vary speed? · Hardware · basis: Xem Studio design following Brown No. 9 (1868)

Also called: cone pulleys, speed cones, variable speed pulleys, poleas cónicas, Kegelscheiben (Kegeltrieb)

Exact dimensions. True size, with no printing tolerance added.

sizes
5 in table

Notes

  • Two identical cones mounted head to tail: sliding the belt along them changes the ratio smoothly, from r_small/r_large to r_large/r_small, while the sum of the two radii — and so the belt length, nearly — stays the same.
  • Here Ø24–Ø56 × 64 cones at 110 mm; at 20 mm along, Ø34 drives Ø46, ratio 0.74. With straight cones an open belt is -1.54 mm slacker near the ends than in the middle (No. 10's curved cones fix that).
  • Brown's No. 9 (cones for gradually increasing or decreasing speed, as in cotton machinery). The belt section lies flat on each cone; its strands twist between the two tilts.
  • Parts (each has its own page): cone-pulley-24-56x64-bore8, flat-belt-10x1-5-cone-pulleys-c110.
  • Brown's movement No. 9 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.

Cone pulleys (speed cones) for gradually varied speed size chart

parametervalue
pulleys2 × Ø24–Ø56 × 64, head to tail
centres110 mm
ratio range0.43 – 2.33
drawn at 20 mmratio 0.74
belt10 × 1.5, 345.99 mm

Where the files are

Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.

Henry T. Brown (1868, public domain)Five Hundred and Seven Mechanical Movements — scan on archive.orgwebPublisher's page; dimensions are facts
507movements.comBrown's movement No. 9: figure, his text and an animationwebPublisher's page; dimensions are facts

Free files

★ Free files 1 parts. Xem Studio design: free to use, print and sell things from; not to be republished as files. Xem Studio Design License. index.json

cone-pulleys-mechanism-assemblyAssembled mechanism, all parts placed at one pose (STEP keeps each part separate)STEP · STL
Let your AI pull this. Add https://xemstudio.com/mcp to Claude, ChatGPT, Cursor or any MCP client (free, no account, one minute) and it can look up exact sizes, mating fits and free STEP/STL from every chat.
Set it up →

Plain text: sheet.txt · JSON: /api/geometry?object=cone-pulleys-mechanism

Cone pulleys (speed cones) for gradually varied speed, isometric render of a generated part
Render of cone-pulleys-mechanism-assembly from the free STEP; not to scale.

Fits with

Cone pulley Ø24 → Ø56 × 64, Ø8 bore, isometric render of a generated part
Cone pulley Ø24 → Ø56 × 64, Ø8 bore56.0×56.0×64.0 mm★ 1 file
Flat belt 10 × 1.5 for two cone pulleys at 110 mm (loop drawn at 20 mm along), isometric render of a generated part
Flat belt 10 × 1.5 for two cone pulleys at 110 mm (loop drawn at 20 mm along)155.34×51.34×10.43 mm★ 1 file

Questions

How do cone pulleys vary speed?

Two identical cones mounted head to tail: sliding the belt along them changes the ratio smoothly, from r_small/r_large to r_large/r_small, while the sum of the two radii — and so the belt length, nearly — stays the same.