{
 "version": "2026-10-20",
 "license": "Dimension sheets: CC BY 4.0. Standard and published-size files: CC BY 4.0. Xem Studio's own designs (files_license = Xem Studio Design License): free to use and sell things from, not to redistribute as files — https://xemstudio.com/license/. Other publishers' files: their own license, linked beside them.",
 "slug": "cam-between-rollers-yoke-mechanism",
 "name": "Constant-diameter cam between two rollers in a yoke",
 "kind": "hardware",
 "category": "Mechanisms",
 "group": "Cams",
 "year": null,
 "question": "How can a cam drive a yoke both ways without a spring?",
 "tags": [
  "mechanism",
  "cams",
  "kinematics",
  "507 mechanical movements"
 ],
 "aliases": [
  "constant diameter cam",
  "cam and yoke",
  "positive drive cam",
  "cam between two rollers",
  "leva de diámetro constante entre rodillos",
  "Gleichdickkurve im Rollenrahmen"
 ],
 "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/cam-between-rollers-yoke-mechanism/",
 "sheet_txt": "https://xemstudio.com/objects/cam-between-rollers-yoke-mechanism/sheet.txt",
 "sheet": {
  "basis": "Xem Studio design following Brown No. 117 (1868)",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "The cam turns between two rollers carried on one yoke. Its pitch curve has a constant diameter (opposite radii always add to the roller spacing), so both rollers stay in contact all round and the yoke is pushed one way by one roller's side of the cam and back by the other's.",
   "Pitch curve r = 22 + 6 sin θ − sin 3θ, rollers Ø10 (623 bearings on Ø3 pins) 44 mm apart: stroke 14 mm per turn. Drawn at 35°: yoke -2.48 mm from centre, both rollers touching.",
   "Brown's No. 117 (a cam between two rollers in a yoke working a slide-valve rod).",
   "Parts (each has its own page): constant-diameter-cam-c22-a6-b1-bore8, two-roller-cam-yoke-44-rods-8, ball-bearings-metric, dowel-pins-metric, linear-shafts-h6.",
   "Brown's movement No. 117 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size."
  ],
  "table": {
   "columns": [
    "parameter",
    "value"
   ],
   "rows": [
    [
     "pitch curve",
     "22 + 6 sin θ − sin 3θ"
    ],
    [
     "roller spacing",
     "44 mm"
    ],
    [
     "stroke",
     "14 mm"
    ],
    [
     "rollers",
     "623 bearings"
    ]
   ]
  }
 },
 "sheet_text": "Constant-diameter cam between two rollers in a yoke — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/cam-between-rollers-yoke-mechanism/  (sheet CC BY 4.0; files Xem Studio Design License, https://xemstudio.com/license/)\nBasis: Xem Studio design following Brown No. 117 (1868)\nCatalog version: 2026-10-20\n\nSizes: see table below\n- The cam turns between two rollers carried on one yoke. Its pitch curve has a constant diameter (opposite radii always add to the roller spacing), so both rollers stay in contact all round and the yoke is pushed one way by one roller's side of the cam and back by the other's.\n- Pitch curve r = 22 + 6 sin θ − sin 3θ, rollers Ø10 (623 bearings on Ø3 pins) 44 mm apart: stroke 14 mm per turn. Drawn at 35°: yoke -2.48 mm from centre, both rollers touching.\n- Brown's No. 117 (a cam between two rollers in a yoke working a slide-valve rod).\n- Parts (each has its own page): constant-diameter-cam-c22-a6-b1-bore8, two-roller-cam-yoke-44-rods-8, ball-bearings-metric, dowel-pins-metric, linear-shafts-h6.\n- Brown's movement No. 117 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.\n\nparameter  value\npitch curve  22 + 6 sin θ − sin 3θ\nroller spacing  44 mm\nstroke  14 mm\nrollers  623 bearings\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- 507movements.com: Brown's movement No. 117: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_117.html\n\nFree files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/cam-between-rollers-yoke-mechanism/index.json\nAPI: https://xemstudio.com/api/geometry?object=cam-between-rollers-yoke-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
  },
  {
   "publisher": "507movements.com",
   "title": "Brown's movement No. 117: figure, his text and an animation",
   "url": "https://507movements.com/mm_117.html",
   "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": [
  "constant-diameter-cam-c22-a6-b1-bore8",
  "two-roller-cam-yoke-44-rods-8",
  "ball-bearings-metric",
  "dowel-pins-metric",
  "linear-shafts-h6"
 ],
 "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": "How can a cam drive a yoke both ways without a spring?",
   "a": "The cam turns between two rollers carried on one yoke. Its pitch curve has a constant diameter (opposite radii always add to the roller spacing), so both rollers stay in contact all round and the yoke is pushed one way by one roller's side of the cam and back by the other's."
  }
 ],
 "files_license": {
  "name": "Xem Studio Design License",
  "holder": "Xem Studio",
  "url": "https://xemstudio.com/license/",
  "note": "Xem Studio's own design: free to use, print, modify and sell things made from it; not to be republished or redistributed as files."
 },
 "offers": [
  {
   "file": "cam-between-rollers-yoke-mechanism-assembly",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/cam-between-rollers-yoke-mechanism/cam-between-rollers-yoke-mechanism-assembly.step",
   "stl": "https://xemstudio.com/files/hardware/cam-between-rollers-yoke-mechanism/cam-between-rollers-yoke-mechanism-assembly.stl",
   "note": "Assembled mechanism, all parts placed at one pose (STEP keeps each part separate)"
  }
 ],
 "markdown": "https://xemstudio.com/objects/cam-between-rollers-yoke-mechanism/index.md"
}