Eccentric in a slotted yoke (harmonic straight-line motion) — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/eccentric-and-slotted-yoke-mechanism/  (CC BY 4.0)
Basis: Xem Studio design following Brown No. 90 (1868)
Catalog version: 2026-10-20

Sizes: see table below
- An eccentric (a disc turning about an off-centre shaft) inside a yoke whose two faces touch it: the yoke moves straight with simple harmonic motion, y = e·sin θ, stroke 2e = 10 mm here.
- It is the eccentric form of the Scotch yoke: no pin, the whole disc is the crank; contact is on the two flat faces.
- Brown's No. 90 (No. 89 with the strap replaced by a yoke so the rod does not swing).
- Parts (each has its own page): eccentric-sheaves, eccentric-slotted-yoke-30, dowel-pins-metric.
- Brown's movement No. 90 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.

parameter  value
eccentric  Ø30, 5 mm offset (catalog part)
stroke  10 mm
yoke slot  30 mm

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Henry T. Brown (1868, public domain): Five Hundred and Seven Mechanical Movements — scan on archive.org — web — Publisher's page; dimensions are facts — https://archive.org/details/fivehundredseven00browiala
- 507movements.com: Brown's movement No. 90: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_090.html

Free files (CC BY 4.0, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/eccentric-and-slotted-yoke-mechanism/index.json
API: https://xemstudio.com/api/geometry?object=eccentric-and-slotted-yoke-mechanism