{
 "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": "opposed-ratchets-bevel-gears-rocking-mechanism",
 "name": "Rocking shaft driving an upright shaft continuously through two opposed ratchets and bevel gears",
 "kind": "hardware",
 "category": "Mechanisms",
 "group": "Intermittent motion",
 "year": null,
 "question": "How can a rocking shaft drive another shaft round continuously?",
 "tags": [
  "mechanism",
  "intermittent motion",
  "kinematics",
  "507 mechanical movements"
 ],
 "aliases": [
  "opposed ratchets",
  "ratchet rectifier",
  "oscillating to continuous rotation",
  "double ratchet bevel",
  "trinquetes opuestos con engranajes cónicos",
  "Gegenläufige Klinkenräder mit Kegelrädern"
 ],
 "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/opposed-ratchets-bevel-gears-rocking-mechanism/",
 "sheet_txt": "https://xemstudio.com/objects/opposed-ratchets-bevel-gears-rocking-mechanism/sheet.txt",
 "sheet": {
  "basis": "Xem Studio design following Brown No. 49 (1868)",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "Resize: multiply every length by one factor k and the motion stays identical: angles, ratios, timing and the formulas below do not change, because a mechanism's motion depends only on the ratios of its lengths. Here, stays the same: gears, ratchets.",
   "Resize: fit clearances stay in mm (a slide fit is the same gap at any size); keep every printed wall and pin at least two nozzle widths; mass grows with k³ but part strength only with k², so at k = 2 parts are about 8× heavier and 4× stronger: check pins and thin links when scaling up.",
   "Two mitre gears ride loose on the rocking cross shaft, facing each other across a third gear on the upright shaft. Each carries a ratchet wheel; a pawl on an arm keyed to the cross shaft drives each, the two ratchets set opposite ways.",
   "Rocking one way, pawl A drives gear A; rocking back, pawl B drives gear B. Because A and B sit on opposite sides of the upright gear, both turn it the same way: the upright shaft goes round (almost) continuously while the cross shaft only rocks.",
   "Built from three module 2, 24-tooth spherical-involute mitre gears (cone distance 33.94 mm) and two copies of the catalog 24-tooth ratchet, feed pawl and feed arm (Brown No. 225 parts); the gears were checked in mesh at six angles. Brown's No. 49.",
   "Parts (each has its own page): mitre-gear-m2-24t-bore5, ratchet-wheels, ratchet-feed-pawl-24t-d40, ratchet-feed-arm-30, linear-shafts-h6.",
   "Brown's movement No. 49 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size."
  ],
  "table": {
   "columns": [
    "parameter",
    "value"
   ],
   "rows": [
    [
     "gears",
     "3 × mitre, module 2, 24 T"
    ],
    [
     "ratchets",
     "2 × 24 T Ø40, opposite hands"
    ],
    [
     "input",
     "cross shaft rocking"
    ],
    [
     "output",
     "upright shaft, one direction"
    ]
   ]
  }
 },
 "sheet_text": "Rocking shaft driving an upright shaft continuously through two opposed ratchets and bevel gears — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/opposed-ratchets-bevel-gears-rocking-mechanism/  (sheet CC BY 4.0; files Xem Studio Design License, https://xemstudio.com/license/)\nBasis: Xem Studio design following Brown No. 49 (1868)\nCatalog version: 2026-10-20\n\nSizes: see table below\n- Resize: multiply every length by one factor k and the motion stays identical: angles, ratios, timing and the formulas below do not change, because a mechanism's motion depends only on the ratios of its lengths. Here, stays the same: gears, ratchets.\n- Resize: fit clearances stay in mm (a slide fit is the same gap at any size); keep every printed wall and pin at least two nozzle widths; mass grows with k³ but part strength only with k², so at k = 2 parts are about 8× heavier and 4× stronger: check pins and thin links when scaling up.\n- Two mitre gears ride loose on the rocking cross shaft, facing each other across a third gear on the upright shaft. Each carries a ratchet wheel; a pawl on an arm keyed to the cross shaft drives each, the two ratchets set opposite ways.\n- Rocking one way, pawl A drives gear A; rocking back, pawl B drives gear B. Because A and B sit on opposite sides of the upright gear, both turn it the same way: the upright shaft goes round (almost) continuously while the cross shaft only rocks.\n- Built from three module 2, 24-tooth spherical-involute mitre gears (cone distance 33.94 mm) and two copies of the catalog 24-tooth ratchet, feed pawl and feed arm (Brown No. 225 parts); the gears were checked in mesh at six angles. Brown's No. 49.\n- Parts (each has its own page): mitre-gear-m2-24t-bore5, ratchet-wheels, ratchet-feed-pawl-24t-d40, ratchet-feed-arm-30, linear-shafts-h6.\n- Brown's movement No. 49 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.\n\nparameter  value\ngears  3 × mitre, module 2, 24 T\nratchets  2 × 24 T Ø40, opposite hands\ninput  cross shaft rocking\noutput  upright shaft, one direction\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. 49: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_049.html\n\nFree files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/opposed-ratchets-bevel-gears-rocking-mechanism/index.json\nAPI: https://xemstudio.com/api/geometry?object=opposed-ratchets-bevel-gears-rocking-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. 49: figure, his text and an animation",
   "url": "https://507movements.com/mm_049.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": [
  "mitre-gear-m2-24t-bore5",
  "ratchet-wheels",
  "ratchet-feed-pawl-24t-d40",
  "ratchet-feed-arm-30",
  "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 rocking shaft drive another shaft round continuously?",
   "a": "Two mitre gears ride loose on the rocking cross shaft, facing each other across a third gear on the upright shaft. Each carries a ratchet wheel; a pawl on an arm keyed to the cross shaft drives each, the two ratchets set opposite ways."
  }
 ],
 "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": "opposed-ratchets-bevel-gears-rocking-mechanism-assembly",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/opposed-ratchets-bevel-gears-rocking-mechanism/opposed-ratchets-bevel-gears-rocking-mechanism-assembly.step",
   "stl": "https://xemstudio.com/files/hardware/opposed-ratchets-bevel-gears-rocking-mechanism/opposed-ratchets-bevel-gears-rocking-mechanism-assembly.stl",
   "note": "Assembled mechanism, all parts placed at one pose (STEP keeps each part separate)"
  }
 ],
 "markdown": "https://xemstudio.com/objects/opposed-ratchets-bevel-gears-rocking-mechanism/index.md"
}