Subject:
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How to get non-circular movements?
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Newsgroups:
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lugnet.technic
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Date:
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Mon, 23 Aug 2004 16:05:53 GMT
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Viewed:
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3514 times
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Short question: how can I combine technic gears, arms, cams, etc. to make a
motor-driven part that does not move in either a straight line, a circle, or an
arc (i.e. part of a circle)?
Long question: I'm trying to figure out how to drive an arm so that the tip
traces out an oval or elliptical path. But using only standard technic parts,
I'm stumped. Gears and wheels obviously move in perfect circles, as do anything
attached to a cam at a fixed point. An arm attached to a gear and a pivot point
sweeps out a circular arc. And a piston attached to either of those moves in a
straight line, back and forth.
And that's it, that's all I could come up with. In custom machines, other paths
are often created by attachment to non-circular cams, such that the radius of
the attachment point to the rotation point varies as it turns. But I don't see
any way to do that with standard lego parts.
Any ideas? Or is this just a limitation we live with?
Thanks,
- Joe
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Message has 5 Replies:
 | | Re: How to get non-circular movements?
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| (...) Have an arm attached off-center on a gear, running through a fixed pivot point (that is free to rotate!). As the main gear rotates, the distance between the driven end of the arm and the pivot point changes as the off-center attatchment point (...) (20 years ago, 23-Aug-04, to lugnet.technic)
| | | Re: How to get non-circular movements?
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| (...) In a stange tie in, I remember seeing a elliptical lathe on an episode of the New Yankee Workshop (a PBS woodworking show). A quick google search turned (no pun intended) up the following: (URL) (20 years ago, 23-Aug-04, to lugnet.technic)
| | | Re: How to get non-circular movements?
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| Hello, A very simple way to produce an elliptical motion is to start with a circular motion and use a lever system to increase the travel on one axis but not the other. Here are a couple of links to some walkers I've made as illustrations: (URL) (...) (20 years ago, 25-Aug-04, to lugnet.technic)
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