Planetary Gear Puzzle Box

prusaprinters

<p>Not much of a puzzle, really. Just turn the knob.</p> <p>Print in place, fully assembled, no supports. Just be sure to have your tolerances dialled in and your slicer preserves the one-layer gap in the outer ring gears. After printing, remove core and separate ring gears with something sharp like a spatula or razor blade.</p> <p>Update: Increased tolerances from initial version. Should print fully assembled but I'd still recommend printing core and shell separately for smoothest finish which is important for sliding.</p> <p>Updated math, verified by reality...</p> <p>Gear ratios relative to top (fixed) gear: (formulas included in scad)<br/> P1 P2 R1 R2 S1=2P1 S2=2P2 Gear Ratio<br/> 8 5 34 20 16 10 1:50<br/> 8 6 34 23 16 12 1:28.75 (4:115=5x23)<br/> 8 7 34 26 16 14 1:21.6667 (3:65=5x13)</p> <p>We can forget the fractional turns, since it must at least be a multiple of 50 (a whole number) giving us a lowest common multiple of 50x13x23 = 14950</p> <p>So that 14950 turns of input knob gives:<br/> 14950/50 (299 turns of first layer)<br/> 14950x4/115 (520 turns of second layer)<br/> 14950x3/65 (690 turns of third layer)</p> <p>By my reckoning, 14950 turns are required for a complete cycle, this is demonstrated in the <a href="https://youtu.be/eBaYPAqvHD4">accompanying video</a>. That's lower than it could be since all layers share a common factor of 5 in this case (probably due to having 5 planets).</p> Category: Puzzles