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Lever with two pawls driving a ratchet on both strokes

How can a lever drive a ratchet on both its strokes? · Hardware · basis: Xem Studio design following Brown No. 206 (1868)

Also called: double pawl ratchet, two pawl lever, continuous ratchet drive, palanca de dos trinquetes, Doppelklinkenschaltwerk

Exact dimensions. True size, with no printing tolerance added.

sizes
3 in table

Notes

  • A lever rocks on a fulcrum beside the ratchet wheel and carries two pawls, pinned one above and one below the fulcrum. Swinging the handle one way, the upper pawl pivot moves toward the wheel and its pawl pushes a tooth; swinging it back, the lower pivot moves toward the wheel and the lower pawl pushes another tooth, while the first slides back over the teeth. The wheel is driven the same way on both strokes, so the motion is nearly continuous.
  • Catalog Ø40, 24-tooth ratchet; both pawls drawn with their end faces lying on the steep faces of two teeth (face contact, no overlap) at the same instant.
  • Brown's No. 206 (lever with rising and falling pawls giving a nearly continuous rotary motion to a ratchet wheel).
  • Parts (each has its own page): ratchet-and-pawl, lever-pawl-24t-d40-upper, lever-pawl-24t-d40-lower, double-pawl-lever-fulcrum-handle-80, dowel-pins-metric.
  • Brown's movement No. 206 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.

Lever with two pawls driving a ratchet on both strokes size chart

parametervalue
ratchet24 T, Ø40
pawls2, face contact
driveboth strokes, same direction

Where the files are

Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.

Henry T. Brown (1868, public domain)Five Hundred and Seven Mechanical Movements — scan on archive.orgwebPublisher's page; dimensions are facts
507movements.comBrown's movement No. 206: figure, his text and an animationwebPublisher's page; dimensions are facts

Free files

★ Free files 1 parts. Xem Studio design: free to use, print and sell things from; not to be republished as files. Xem Studio Design License. index.json

double-pawl-lever-ratchet-mechanism-assemblyAssembled mechanism, all parts placed at one pose (STEP keeps each part separate)STEP · STL
Let your AI pull this. Add https://xemstudio.com/mcp to Claude, ChatGPT, Cursor or any MCP client (free, no account, one minute) and it can look up exact sizes, mating fits and free STEP/STL from every chat.
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Plain text: sheet.txt · JSON: /api/geometry?object=double-pawl-lever-ratchet-mechanism

Lever with two pawls driving a ratchet on both strokes, isometric render of a generated part
Render of double-pawl-lever-ratchet-mechanism-assembly from the free STEP; not to scale.

Fits with

Ratchet wheels Ø40 with 12, 24 and 36 teeth, isometric render of a generated part
Ratchet wheels Ø40 with 12, 24 and 36 teeth3 sizes★ 3 files
Pawl for the 24-tooth Ø40 ratchet, pivot to nose 30.89 mm, isometric render of a generated part
Pawl for the 24-tooth Ø40 ratchet, pivot to nose 30.89 mm34.89×8.0×6.0 mm★ 1 file
Pawl for the 24-tooth Ø40 ratchet, pivot to nose 26.87 mm, isometric render of a generated part
Pawl for the 24-tooth Ø40 ratchet, pivot to nose 26.87 mm30.87×8.0×6.0 mm★ 1 file
Double-pawl lever: fulcrum, two pawl pivots and an 80 mm handle, isometric render of a generated part
Double-pawl lever: fulcrum, two pawl pivots and an 80 mm handle97.0×47.0×5.0 mm★ 1 file
Dowel pins, 2–6 mm (ISO 2338 / DIN 6325), isometric render of a generated part
Dowel pins, 2–6 mm (ISO 2338 / DIN 6325)5 sizes★ 23 files

Questions

How can a lever drive a ratchet on both its strokes?

A lever rocks on a fulcrum beside the ratchet wheel and carries two pawls, pinned one above and one below the fulcrum. Swinging the handle one way, the upper pawl pivot moves toward the wheel and its pawl pushes a tooth; swinging it back, the lower pivot moves toward the wheel and the lower pawl pushes another tooth, while the first slides back over the teeth. The wheel is driven the same way on both strokes, so the motion is nearly continuous.