Rowing Mechanism

Mon, 27 Jan 2014

I’ve made a couple of rowing models in the past. This one is the Shrimp Boat and is part of the Gizmos pack produced by Barnes and Nobel.
The models that I have produced so far have used a crank/slider mechanism to drive the oars. To do this I have used a tall box with the drive handle located low down so that the slider tube doesn’t need to swing back and forth excessively.

 


For a forthcoming project I need the box to be much shallower in relation to the length of the boat. To that end I have come up with this mechanism which uses a crank and a couple of linkages.
The black line (the locus) traces out the path the end of the push rod takes. It’s interesting just how un-circular the locus turns with only the addition of a couple of links, geometry is an amazingly flexible tool. With luck and experiment I’ll be able to tune the locus to just the movement I’m after.
Thinking about it, I probably want the locus to be exactly upside down from what it is now. When the push rod is at its highest the oars will be in the water and should be being pulled back flat and level. I’m sure that can be arranged.

 


The whole assembly should fit nicely in a shallow box just beneath the waves.

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Comments (4)

  • hugo leandro January 28, 2014 at 2:27 pm

    It looks gorgeous this
    It looks gorgeous this project. I can’t hardly wait to see this magnific result. Good luck with this project, Rob.

  • umehta January 29, 2014 at 12:57 pm

    I believe half of ellipse
    I believe half of ellipse trammel of Archimedes could help or solve it?

    http://en.wikipedia.org/wiki/Trammel_of_Archimedes

    • Smelter January 29, 2014 at 4:10 pm

      umehta
      That is one serious

      umehta

      That is one serious “oar” gate 😉

  • Andy from Workshopshed January 31, 2014 at 4:09 pm

    If you made the “horizonal”
    If you made the “horizonal” beam arc downwards then it would hide better inside the boat as it moved.

Comments are closed.