JANSEN LINKAGE - BUILD-IT-YOURSELF CUT KIT
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Every part here is one I designed in CAD, cut, and bolted into a walking Jansen
linkage. All files are 2D profiles for a laser cutter or a CNC router: lines,
arcs, circles and polylines only, no splines. Units are MILLIMETRES.

final_cut/  the parts at final cut scale
  main_body.dxf        the main body - carries all five fixed pivots
  frame_bar.dxf        frame bar
  link_bar_39.4.dxf    link bar, 360.35 mm between holes
  link_bar_50.dxf      link bar, 457.29 mm between holes
  link_bar_61.9.dxf    drive bar, 566.13 mm between holes
  knee_plate.dxf       knee plate, 3 pivot holes
  foot_plate.dxf       foot plate, 2 pivot holes + the toe hole
  ring_gear_40T.dxf    ring gear, 40 teeth, doubles as the leg's crank disc
  pinion_10T.dxf       the single pinion that drives both ring gears

HOW THE MAIN BODY SITS IN THE ASSEMBLY
  main_body.dxf is positioned so its five holes land exactly on the frame bar's
  five fixed pivots (worst miss 0.000000000 mm over all five). Drop it on top of
  frame_bar.dxf in your CAD and every hole lines up. As drawn it is split into
  three sections by two 7.775 mm slots.

GEAR TRAIN, measured off the files
  module m = 9.145875 mm = 1 design unit
  ring gear 40 T, pitch radius 182.9175 mm
  pinion   10 T, pitch radius  45.7294 mm
  4:1 reduction, centre distance 228.6469 mm (= 25 units), tangent contact
  one pinion drives both ring gears, so both legs run in phase

NOTES
  * Every hole is 5.9 mm across (r = 2.95 mm) except the knee's third hole
    (r = 3.95 mm) - sized for M5 hardware through 3 mm plate.
  * In the foot plate the heel hole sits ON the toe edge: the rounded toe was
    pulled back until the hole centre met the outline, so that hole is a
    half-open mouth on purpose, not a drawing error.
  * Each corner is stored as an arc inside the outline polyline (a "bulge"
    value), so every outline is one closed path - no duplicate arcs.

The solver that produced these simulations, and the two animation clips, are in
the separate jansen_sim_pack.zip on the same page.

LICENCE: MIT. Take it, cut it, change it. A credit is nice, a photo is nicer.

