Subject:
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RE: Discontinuous motion.
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Newsgroups:
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lugnet.robotics
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Date:
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Tue, 2 Apr 2002 14:27:03 GMT
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Original-From:
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Wittig, Bill <bill.wittig@delphiauto.*stopspam*com>
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Viewed:
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585 times
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Try looking at the mechanisms at http://www.brockeng.com/mechanism/index.htm.
I find this to be a great reference site for basic kinematics.
bill
-----Original Message-----
From: Steve Baker [mailto:sjbaker1@airmail.net]
Sent: Saturday, April 06, 2002 12:07 AM
To: Lego Robotics
Subject: Discontinuous motion.
I'm trying to build a mechanism that converts continuous rotation on
one axle into a periodic short rotation on another. I could imagine
a way to do this by filing off most of the teeth from one gear wheel
so that it would only turn an adjacent gear for a small part of it's
revolution - but I don't want to modify any Lego parts or use non-Lego
components.
I tried a couple of things (both failed):
* I attached a 24t gear to a 40t using a couple of black pegs through
the holes around the edge of each wheel. This made the teeth of the
24t stick out a bit beyond the 40t's radius. Turning the 40t by it's
center hole and meshing the 24t's teeth with a second 24t gear
looks like it should work quite nicely. When I turn this contraption
by hand, the mechanism works OK - but when I motorize it, it jams
every few seconds.
* I hooked up a reciprocating rod to a 40t wheel - and mounted a rack
plate to the rod such that it just contacts an 8t gear for a short
part of it's cycle. This also works - and although it doesn't jam,
it operates rather violently and tends to destroy itself in short
order. It's also incapable of transmitting any significant amount
of power.
There must be a good way of doing this - but after an entire evening
of tinkering, I havn't come up with anything usable.
Help!
----------------------------- Steve Baker -------------------------------
Mail : <sjbaker1@airmail.net> WorkMail: <sjbaker@link.com>
URLs : http://www.sjbaker.org
http://plib.sf.net http://tuxaqfh.sf.net http://tuxkart.sf.net
http://prettypoly.sf.net http://freeglut.sf.net
http://toobular.sf.net http://lodestone.sf.net
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Message has 4 Replies:
 | | Re: Discontinuous motion.
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| Great reference, thanks Bill. I had forgotten about the Geneva mechanism. Any interest, Steve? If you'd consider filing the teeth off a gear, how about an honest to goodness made to measure couple of Geneva mechanism parts? JB (...) (23 years ago, 2-Apr-02, to lugnet.robotics)
| | | Re: Discontinuous motion.
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| Bill, This exact same question was posted several months ago but I don't remember the sollution that they came to. This is my Idea: Ok you take two pulleys, pulley (A) is smaller then pulley (B). You then conect the 2 pulleys via a linkage so that (...) (23 years ago, 2-Apr-02, to lugnet.robotics)
| | | Re: Discontinuous motion.
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| (...) Yes - pretty good stuff. So it looks like I need to find an 'interpretation' of that Geneva Escapement in Lego. (Yikes!) ---...--- Steve Baker ---...--- Mail : <sjbaker1@airmail.net> WorkMail: <sjbaker@link.com> URLs : (8 URLs) (23 years ago, 3-Apr-02, to lugnet.robotics)
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