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Belt drive between shafts at right angles with two guide pulleys

How do guide pulleys carry a belt round a right angle? · Hardware · basis: Xem Studio design following Brown No. 3 (1868)

Also called: guide pulley belt, right angle belt drive, mule pulley drive, quarter turn belt with idlers, transmisión en ángulo recto con poleas guía, Winkeltrieb mit Leitrollen

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

sizes
4 in table

Notes

  • Two pulleys on shafts at right angles, joined by one belt led over two guide pulleys on a single inclined shaft. Each strand lies in the mid-planes of both pulleys it joins, so the belt runs in either direction without leaving the faces.
  • Here two Ø40 pulleys sit 80 mm apart on the common perpendicular, their belt lines all parallel; the guides (Ø28.28 = 20√2) are 100 mm beyond, on a shaft at 45° to both. Each strand twists 45°; belt 12 × 1.5, inside length 774.52 mm.
  • Brown's No. 3 (guide pulleys carrying the belt between shafts at right angles); No. 4 does it with the belt alone, working one way only.
  • Parts (each has its own page): plain-flat-pulley-40x12, plain-flat-pulley-28-28x12-bore6, flat-belt-12x1-5-right-angle-guide-drive, dowel-pins-metric.
  • Brown's movement No. 3 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.

Belt drive between shafts at right angles with two guide pulleys size chart

parametervalue
pulleys2 × Ø40 × 12, shafts at 90°
guide pulleys2 × Ø28.28 on one shaft at 45°
ratio1 : 1
belt12 × 1.5, 774.52 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. 3: 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

guide-pulley-right-angle-belt-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=guide-pulley-right-angle-belt-mechanism

Belt drive between shafts at right angles with two guide pulleys, isometric render of a generated part
Render of guide-pulley-right-angle-belt-mechanism-assembly from the free STEP; not to scale.

Fits with

Plain flat-belt pulley Ø40 × 12 face, Ø8 bore (no flanges), isometric render of a generated part
Plain flat-belt pulley Ø40 × 12 face, Ø8 bore (no flanges)40.0×40.0×12.0 mm★ 1 file
Guide pulley Ø28.28 × 12, Ø6 bore (plain face), isometric render of a generated part
Guide pulley Ø28.28 × 12, Ø6 bore (plain face)28.28×28.28×12.0 mm★ 1 file
Flat belt 12 × 1.5 for the right-angle guide-pulley drive (loop drawn on the pulleys), isometric render of a generated part
Flat belt 12 × 1.5 for the right-angle guide-pulley drive (loop drawn on the pulleys)50.61×217.14×50.61 mm★ 1 file
Dowel pins, 2–6 mm (ISO 2338 / DIN 6325), isometric render of a generated part
Dowel pins, 2–6 mm (ISO 2338 / DIN 6325)5 sizes★ 23 files

Questions

How do guide pulleys carry a belt round a right angle?

Two pulleys on shafts at right angles, joined by one belt led over two guide pulleys on a single inclined shaft. Each strand lies in the mid-planes of both pulleys it joins, so the belt runs in either direction without leaving the faces.