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Oblong endless rack and pinion (mangle rack)

How does a mangle rack reverse without reversing the pinion? · Hardware · basis: Xem Studio design following Brown No. 119 (1868)

Also called: mangle rack, endless rack and pinion, oblong rack, cremallera de mangle, Mangelradgetriebe (Zahnstange)

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

sizes
4 in table

Notes

  • The rack is an endless oblong loop of teeth; the pinion, turning always the same way, meshes with the top straight and drives the rack one way, rolls round the half-gear end and comes back along the bottom straight driving it the other way. Its shaft moves up and down 20 mm in a slot as it changes sides.
  • Module 1, 20 T pinion; straights 12.57 mm: the rack bar's stroke is the straight length plus the end travel. Drawn with the pinion mid-way along the top straight, its Ø6 axle in the 6.2 mm slot of the catalog guide plate (slot turned vertical).
  • Brown's No. 119 (oblong endless rack on a bar, pinion shaft guided by a slotted bar); the mangle rack of Nos. 197–199 is the same idea in a frame.
  • Parts (each has its own page): oblong-endless-rack-m1-20t-ends, spur-gears-module-1, slot-guide-plate-90, dowel-pins-metric.
  • Brown's movement No. 119 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.

Oblong endless rack and pinion size chart

parametervalue
pinion20 T, module 1, Ø6 axle
rack straights12.57 mm
shaft travel20 mm, in a 6.2 slot
rack stroke≈ 32.57 mm

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. 119: 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

mangle-rack-oblong-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=mangle-rack-oblong-mechanism

Oblong endless rack and pinion (mangle rack), isometric render of a generated part
Render of mangle-rack-oblong-mechanism-assembly from the free STEP; not to scale.

Fits with

Oblong endless rack, module 1: two 4π racks joined by 20-tooth half-gear ends, isometric render of a generated part
Oblong endless rack, module 1: two 4π racks joined by 20-tooth half-gear ends34.56×22.0×8.0 mm★ 1 file
Spur gears, module 1: 10 to 80 teeth (20° involute), isometric render of a generated part
Spur gears, module 1: 10 to 80 teeth (20° involute)26 sizes★ 26 files
Slot guide plate 90 × 30 × 5, 6.2 mm slot (74 long), isometric render of a generated part
Slot guide plate 90 × 30 × 5, 6.2 mm slot (74 long)90.0×30.0×5.0 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 does a mangle rack reverse without reversing the pinion?

The rack is an endless oblong loop of teeth; the pinion, turning always the same way, meshes with the top straight and drives the rack one way, rolls round the half-gear end and comes back along the bottom straight driving it the other way. Its shaft moves up and down 20 mm in a slot as it changes sides.