Heart cam with roller follower (uniform motion) — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/heart-cam-mechanism/  (CC BY 4.0)
Basis: Xem Studio drawing; classic mechanism (Brown No. 96)
Catalog version: 2026-10-20

Sizes: see table below
- Radius = r₀ + h·θ/180° on the way out and back on the way in: equal angle steps give equal lift steps, so the follower moves at a constant speed (20 mm each way per turn here).
- The cusp at the top and the dip at the bottom are where direction reverses (infinite acceleration in theory): fine for slow traverse, e.g. thread winding.
- A roller follower's pitch curve is the profile offset by the roller radius; this file is the pitch-correct profile for a knife-edge follower — offset by 5 mm for the Ø10 roller.
- Parts (each has its own page): heart-cam-r15-h20, roller-follower-10, crosshead-guide-8mm. Brown's movement No. 96 shows it (1868).

parameter  value
base radius r₀  15 mm
lift h  20 mm
motion  uniform velocity

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

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