{
 "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": "segment-lever-band-pulleys-mechanism",
 "name": "Rocking segment and band turning two pulleys to and fro",
 "kind": "hardware",
 "category": "Mechanisms",
 "group": "Belt and friction drives",
 "year": null,
 "question": "How does a rocking segment drive two pulleys?",
 "tags": [
  "mechanism",
  "belt and friction drives",
  "kinematics",
  "507 mechanical movements"
 ],
 "aliases": [
  "segment lever",
  "band drive",
  "oscillating pulley drive",
  "rocking lever band",
  "segmento oscilante con banda",
  "Schwingsegment mit Band"
 ],
 "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/segment-lever-band-pulleys-mechanism/",
 "sheet_txt": "https://xemstudio.com/objects/segment-lever-band-pulleys-mechanism/sheet.txt",
 "sheet": {
  "basis": "Xem Studio design following Brown No. 6 (1868)",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "A lever rocking on a pivot carries a circular segment; a band fixed to both ends of the segment passes round two pulleys below. Rocking the lever pulls the band one way, then the other, so both pulleys turn back and forth together, in the same direction.",
   "Pulley turn = segment turn × R_segment / R_pulley = 50/20 = 2.5: rocking the lever ±20° turns each Ø40 pulley ±50°. The segment's rim spans 198.83° so the band's 174.83° of wrap stays on it.",
   "Band 16 × 1.5, 510.14 mm; pulleys 70 mm apart, 110 mm below the pivot. Brown's No. 6.",
   "Parts (each has its own page): rocking-segment-lever-r50, flanged-flat-pulley-40, band-16x1-5-segment-r50-two-pulleys-40, linear-shafts-h6.",
   "Brown's movement No. 6 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size."
  ],
  "table": {
   "columns": [
    "parameter",
    "value"
   ],
   "rows": [
    [
     "segment radius",
     "50 mm"
    ],
    [
     "pulleys",
     "2 × Ø40 (catalog)"
    ],
    [
     "ratio",
     "2.5 : 1"
    ],
    [
     "band",
     "16 × 1.5, 510.14 mm"
    ]
   ]
  }
 },
 "sheet_text": "Rocking segment and band turning two pulleys to and fro — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/segment-lever-band-pulleys-mechanism/  (sheet CC BY 4.0; files Xem Studio Design License, https://xemstudio.com/license/)\nBasis: Xem Studio design following Brown No. 6 (1868)\nCatalog version: 2026-10-20\n\nSizes: see table below\n- A lever rocking on a pivot carries a circular segment; a band fixed to both ends of the segment passes round two pulleys below. Rocking the lever pulls the band one way, then the other, so both pulleys turn back and forth together, in the same direction.\n- Pulley turn = segment turn × R_segment / R_pulley = 50/20 = 2.5: rocking the lever ±20° turns each Ø40 pulley ±50°. The segment's rim spans 198.83° so the band's 174.83° of wrap stays on it.\n- Band 16 × 1.5, 510.14 mm; pulleys 70 mm apart, 110 mm below the pivot. Brown's No. 6.\n- Parts (each has its own page): rocking-segment-lever-r50, flanged-flat-pulley-40, band-16x1-5-segment-r50-two-pulleys-40, linear-shafts-h6.\n- Brown's movement No. 6 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.\n\nparameter  value\nsegment radius  50 mm\npulleys  2 × Ø40 (catalog)\nratio  2.5 : 1\nband  16 × 1.5, 510.14 mm\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. 6: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_006.html\n\nFree files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/segment-lever-band-pulleys-mechanism/index.json\nAPI: https://xemstudio.com/api/geometry?object=segment-lever-band-pulleys-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. 6: figure, his text and an animation",
   "url": "https://507movements.com/mm_006.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": [
  "rocking-segment-lever-r50",
  "flanged-flat-pulley-40",
  "band-16x1-5-segment-r50-two-pulleys-40",
  "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 does a rocking segment drive two pulleys?",
   "a": "A lever rocking on a pivot carries a circular segment; a band fixed to both ends of the segment passes round two pulleys below. Rocking the lever pulls the band one way, then the other, so both pulleys turn back and forth together, in the same direction."
  }
 ],
 "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": "segment-lever-band-pulleys-mechanism-assembly",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/segment-lever-band-pulleys-mechanism/segment-lever-band-pulleys-mechanism-assembly.step",
   "stl": "https://xemstudio.com/files/hardware/segment-lever-band-pulleys-mechanism/segment-lever-band-pulleys-mechanism-assembly.stl",
   "note": "Assembled mechanism, all parts placed at one pose (STEP keeps each part separate)"
  }
 ],
 "markdown": "https://xemstudio.com/objects/segment-lever-band-pulleys-mechanism/index.md"
}