Tumbling Acrobat – first stages

Tue, 17 Jul 2012

I've been thinking about making a paper version of this classical automata.

Link to the YouTube video

In the original version, mercury flowed inside a steel tube to change the centre of gravity of the acrobat making him tumble down the steps.

In my version I'm using paper tubes and coins. 


The weight of the coins rolling in the long central tube helps move the acrobat.


I've made a start, experimenting with the joints to make them as free as possible and finding a way to limit their arc of rotation. At the moment I have settled on pegs in holes for the joint. The triangular section on the upper surface of the 'leg' works as a movement stop, restricting the rotation to ninety degrees. Looking at the video I suspect that there is a connection between the arms and legs, I'm not sure as it is hard to follow the video but if necessary I'll use paper straps to link them together. 

Comments (4)

  • lunchweek July 17, 2012 at 11:15 pm

    I’m eagerly waiting for this

    I'm eagerly waiting for this one Rob! Gakken from Japan has a kit of this acrobat automata. Seems a little bit different but it may give you an idea:



    And here is how to build video:



    Useful links! Thanks! – RI

  • cool022883 July 18, 2012 at 2:52 am

    in the video lunchweek posted

    in the video lunchweek posted it looks like they use string in the model.maybe you can modify like a belt drive and make it work?well im sure you will figure it out,keep up the great work rob im sure this model will be worth whatever wait there is for you to make it function  right. 

    Hopefully I’ll be able to use paper strips… – RI

  • michael42er July 18, 2012 at 10:49 am

    Great idea. I would be happy

    Great idea. I would be happy if a working paper model is created. I also have a link for a "Tumbling man". At end of the film sketches can be seen.

    Michael



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  • ijustgolf July 24, 2012 at 11:53 pm

    Hey Rob..!    Whats

    Hey Rob..!    Whats up..

    Just eye-balled the Tumbling Man Project, looks very interesting..   i noticed you mentioned trying to free the joints and limit their rotation..   the simple paper hinge used in conjunction with a truncated shaft would be frictionless and stationary (no play)..    i am convinced it is the best application for precision, limited-rotation mechanisms…     and this project has two of those..  even if a hole is cut perfectly round, the shaft will either be exposed to friction from the hole, or play from the hole being a hair too large.  a stationary flat hinge doesn't suffer either of those flaws..    your shaft diameters would need to be bigger and the track for the coin would need to be offset a bit as not to interfere with either pivot shaft/hinge..  from what i can take from the video, its the abnormally long hands and feet crashing into the step below that halts the rotation. 

    any of this peak your interest…?

    be good…     Gum

    Indeed it does, the arms have quite an arm of travel, perhaps 200 degress but the legs at around 100-110 degrees would be perfect for a paper hinge… – RI

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