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Constant-breadth cam: rounded Reuleaux triangle, breadth 40, Ø5 bore at its centre

What is a constant-breadth cam? · Modern device · basis: Xem Studio design following Brown's figure (1868); true size, no printing allowance

Also called: constant breadth cam, rounded reuleaux triangle, constant width cam, leva de anchura constante, Gleichdick (gerundetes Reuleaux-Dreieck)

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

length
40.0 mm
width
40.0 mm
height
8.0 mm

Notes

  • Reuleaux triangle of side 30 (three arcs of R30 about the opposite corners) with every edge offset 5 mm, so the corners are R5 arcs: breadth 40 mm in every direction. Bored Ø5 at its centre: turning there inside a yoke 40 mm wide it always touches both faces and moves the yoke 4.64 mm, three times per turn.
  • Corner (vertex arc centres) on a 17.32 mm circle; largest radius 22.32 mm, smallest 17.68 mm.
  • Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

Constant-breadth cam: rounded Reuleaux triangle, breadth 40, Ø5 bore… size chart

dimensionvalue
breadth40 mm
Reuleaux side30 mm
corner radius5 mm
thickness8 mm
boreØ5 at the centre

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. 276: figure, his text and an animationwebPublisher's page; dimensions are facts
Xem StudiodrawingwebPublisher'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

constant-breadth-cam-s30-r5cam, z 0..8, a corner on +YSTEP · STL
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Plain text: sheet.txt · JSON: /api/geometry?object=constant-breadth-cam-s30-r5-bore5

Constant-breadth cam: rounded Reuleaux triangle, breadth 40, Ø5 bore at its centre, isometric render of a generated part
Render of constant-breadth-cam-s30-r5 from the free STEP; not to scale.

Fits with

Constant-breadth cam turning in a yoke (three strokes per turn), isometric render of a generated part
Constant-breadth cam turning in a yoke (three strokes per turn)4 sizes★ 1 file

Questions

What is a constant-breadth cam?

Reuleaux triangle of side 30 (three arcs of R30 about the opposite corners) with every edge offset 5 mm, so the corners are R5 arcs: breadth 40 mm in every direction. Bored Ø5 at its centre: turning there inside a yoke 40 mm wide it always touches both faces and moves the yoke 4.64 mm, three times per turn.