{
 "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": "round-groove-pulleys-round-band-mechanism",
 "name": "Round-groove pulleys and round band, 1 : 1",
 "kind": "hardware",
 "category": "Mechanisms",
 "group": "Belt and friction drives",
 "year": null,
 "question": "How does a round band sit in a round-groove pulley?",
 "tags": [
  "mechanism",
  "belt and friction drives",
  "kinematics",
  "507 mechanical movements"
 ],
 "aliases": [
  "round belt drive",
  "grooved pulley",
  "o-ring belt drive",
  "poleas de garganta redonda con correa redonda",
  "Rundriemenscheiben mit Rundriemen"
 ],
 "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/round-groove-pulleys-round-band-mechanism/",
 "sheet_txt": "https://xemstudio.com/objects/round-groove-pulleys-round-band-mechanism/sheet.txt",
 "sheet": {
  "basis": "Xem Studio design following Brown No. 257 (1868)",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "The band's section matches the groove, so it is held on half its circumference and cannot ride off; it drives by friction on the groove's surface, like a flat belt but steerable round guide pulleys at any angle.",
   "Two equal pulleys 100 mm apart on Ø8 shafts and a Ø5 endless band, drawn seated in both grooves (band centre radius 20 mm).",
   "Brown's No. 257.",
   "Parts (each has its own page): round-groove-pulley-40-band5-bore8, round-band-5-c100-pulleys-40, linear-shafts-h6.",
   "Brown's movement No. 257 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size."
  ],
  "table": {
   "columns": [
    "parameter",
    "value"
   ],
   "rows": [
    [
     "pulleys",
     "2 × Ø40 × 10 for a Ø5 round band"
    ],
    [
     "band",
     "Ø5 round"
    ],
    [
     "centre distance",
     "100 mm"
    ],
    [
     "ratio",
     "1 : 1"
    ]
   ]
  }
 },
 "sheet_text": "Round-groove pulleys and round band, 1 : 1 — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/round-groove-pulleys-round-band-mechanism/  (sheet CC BY 4.0; files Xem Studio Design License, https://xemstudio.com/license/)\nBasis: Xem Studio design following Brown No. 257 (1868)\nCatalog version: 2026-10-20\n\nSizes: see table below\n- The band's section matches the groove, so it is held on half its circumference and cannot ride off; it drives by friction on the groove's surface, like a flat belt but steerable round guide pulleys at any angle.\n- Two equal pulleys 100 mm apart on Ø8 shafts and a Ø5 endless band, drawn seated in both grooves (band centre radius 20 mm).\n- Brown's No. 257.\n- Parts (each has its own page): round-groove-pulley-40-band5-bore8, round-band-5-c100-pulleys-40, linear-shafts-h6.\n- Brown's movement No. 257 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.\n\nparameter  value\npulleys  2 × Ø40 × 10 for a Ø5 round band\nband  Ø5 round\ncentre distance  100 mm\nratio  1 : 1\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. 257: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_257.html\n\nFree files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/round-groove-pulleys-round-band-mechanism/index.json\nAPI: https://xemstudio.com/api/geometry?object=round-groove-pulleys-round-band-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. 257: figure, his text and an animation",
   "url": "https://507movements.com/mm_257.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": [
  "round-groove-pulley-40-band5-bore8",
  "round-band-5-c100-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 round band sit in a round-groove pulley?",
   "a": "The band's section matches the groove, so it is held on half its circumference and cannot ride off; it drives by friction on the groove's surface, like a flat belt but steerable round guide pulleys at any angle."
  }
 ],
 "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": "round-groove-pulleys-round-band-mechanism-assembly",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/round-groove-pulleys-round-band-mechanism/round-groove-pulleys-round-band-mechanism-assembly.step",
   "stl": "https://xemstudio.com/files/hardware/round-groove-pulleys-round-band-mechanism/round-groove-pulleys-round-band-mechanism-assembly.stl",
   "note": "Assembled mechanism, all parts placed at one pose (STEP keeps each part separate)"
  }
 ],
 "markdown": "https://xemstudio.com/objects/round-groove-pulleys-round-band-mechanism/index.md"
}