{
 "version": "2026-10-20",
 "license": "Dimension sheets are written by Xem Studio from the cited sources and are free to use (CC BY 4.0, attribute 'Xem Studio'). Linked files belong to their publishers under the license shown; Xem Studio does not host them. 'license_verified: false' means the license shown is from memory or the publisher's page as last read and should be confirmed at the link before commercial use.",
 "slug": "heart-cam-mechanism",
 "name": "Heart cam with roller follower (uniform motion)",
 "kind": "hardware",
 "category": "Mechanisms",
 "group": "Cams",
 "year": null,
 "question": "Why is a heart cam heart-shaped?",
 "tags": [
  "mechanism",
  "cams",
  "kinematics"
 ],
 "aliases": [
  "heart cam",
  "heart shaped cam",
  "uniform motion cam"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": false,
 "free_files": 1,
 "url": "https://xemstudio.com/objects/heart-cam-mechanism/",
 "sheet_txt": "https://xemstudio.com/objects/heart-cam-mechanism/sheet.txt",
 "sheet": {
  "basis": "Xem Studio drawing; classic mechanism (Brown No. 96)",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "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)."
  ],
  "table": {
   "columns": [
    "parameter",
    "value"
   ],
   "rows": [
    [
     "base radius r₀",
     "15 mm"
    ],
    [
     "lift h",
     "20 mm"
    ],
    [
     "motion",
     "uniform velocity"
    ]
   ]
  }
 },
 "sheet_text": "Heart cam with roller follower (uniform motion) — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/heart-cam-mechanism/  (CC BY 4.0)\nBasis: Xem Studio drawing; classic mechanism (Brown No. 96)\nCatalog version: 2026-10-20\n\nSizes: see table below\n- 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).\n- 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.\n- 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.\n- Parts (each has its own page): heart-cam-r15-h20, roller-follower-10, crosshead-guide-8mm. Brown's movement No. 96 shows it (1868).\n\nparameter  value\nbase radius r₀  15 mm\nlift h  20 mm\nmotion  uniform velocity\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- 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\n\nFree files (CC BY 4.0, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/heart-cam-mechanism/index.json\nAPI: https://xemstudio.com/api/geometry?object=heart-cam-mechanism\n",
 "sources": [
  {
   "publisher": "Henry T. Brown (1868, public domain)",
   "title": "Five Hundred and Seven Mechanical Movements — scan on archive.org",
   "url": "https://archive.org/details/fivehundredseven00browiala",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  }
 ],
 "xem": {
  "status": "free-files",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "heart-cam-r15-h20",
  "roller-follower-10",
  "crosshead-guide-8mm"
 ],
 "fits": [],
 "dimensions": "exact (nominal, no printing tolerance)",
 "dimension_rule": "All geometry on Xem Studio is exact (nominal, true size) with no printing tolerance. Where a part meets another part, the object lists its mating features (feature, exact size, what it mates with, fit class: press, slide, run, socket, clamp or designed). Apply your process's allowance to those features only; 'designed' gaps are part of the design and stay as drawn.",
 "mating": [],
 "faq": [
  {
   "q": "Why is a heart cam heart-shaped?",
   "a": "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)."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "heart-cam-mechanism-assembly",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/heart-cam-mechanism/heart-cam-mechanism-assembly.step",
   "stl": "https://xemstudio.com/files/hardware/heart-cam-mechanism/heart-cam-mechanism-assembly.stl",
   "note": "Assembled mechanism, all parts placed (STEP keeps each part separate)"
  }
 ],
 "markdown": "https://xemstudio.com/objects/heart-cam-mechanism/index.md"
}