Steam-powered Hexapod

This all-mechanical hexapod (translated) was meticulously planned and beautifully constructed. It’s not craning its neck to see what’s ahead. That’s a smoke stack for the steam engine which propels the machine.

Mechanically the legs were the hardest part. That’s only because the steam engine was not built from scratch. It’s a Wilesco D14 which is powered by solid fuel tablets. It puts out high RPM but low power so the gear ratio was set at 286:1 to make the most of its output.

The legs themselves are made of brass rods. These are anchored on one side of a larger gear, with a pivot point that allows the leg to slide vertically. The result is best seen in the clip after the break. As the drive wheel rotates, the pivot point moves the body forward until the foot is lifted by the sliding motion of the rod. It ends up looking more elegant than some of the more dexterous hexapods, but it lacks the ability to turn.

25 thoughts on “Steam-powered Hexapod

  1. I have i have this exact steam engine (or probably an older version as i got it as a kid and it was old then) in a box somewhere. it has other miniature woodworking shop components, like a table saw and drill press that all connect via belts.

    awesome use of old tech!

  2. I build a similar design out of lego once upon a time, and struggled and struggled to come up with a way for it to turn. My solution was to make the fulcrum bars movable – by raising and lowering them, you alter the stride length of each side, allowing you to turn in a neat circle. The next lego version could turn… but it was so slow… so… slow… :)

    1. The steam walker by Crabfu was my main insipration, as I dutifully mention in my blog post :) Though the finish is awesome, I didn’t like the way it walked, with the hind legs always on the ground and the front legs seeming to paddle their way. The 6-legged design give it a more “fluid” walk.

  3. Thank you all for the nice comments!

    I thought about an articulated body, but the design of the transmission, made of fixed-diameter gears, wouldn’t allow it. The main problem would then be to keep the six legs synchronized. A way to do this would be with some kind of microcontroller like an Arduino, but where would all the fun be if it had to use batteries? ;)

    @Paul, I’m not sure what the “fulcrum bars” are, but it seems like an intersting solution.

    1. @Prof Shadoko: I thing by “fulcrum bars” Paul means the horizonal bars to which the pivot points (that the legs slide through) are attached. On your version, those pivots are attached to the bottom edge of the frame, but of course on a Lego version that piece of the frame would be a Lego bar.

      The general idea, though, is that you would raise and lower the pivot points with respect to the rest of the frame and the gears. There are a lot of ways to do that — but, of course, doing it sturdily is the trick!

      1. That’s correct the fulcrum bars at the horizontal elements with all the sliding pivots on it. This approach keeps all the legs synced, (important, because they’re clockwork!). The mechanism I used was a chain drive loop that linked into the bars at the sides, so that rotating a gear at the top lifted one bar and lowered the other.

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