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Subject: 
Re: Discontinuous motion.
Newsgroups: 
lugnet.robotics
Date: 
Tue, 2 Apr 2002 14:43:26 GMT
Viewed: 
1775 times
  
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


In lugnet.robotics, "Wittig, Bill " <bill.wittig@delphiauto.com> writes:
> 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



Message has 1 Reply:
  Re: Discontinuous motion.
 
(...) No - I *won't* consider hacking away at my Lego parts - however, it may be possible to take that idea and build something that would be similar. ---...--- Steve Baker ---...--- Mail : <sjbaker1@airmail.net> WorkMail: <sjbaker@link.com> URLs : (...) (25 years ago, 3-Apr-02, to lugnet.robotics)

Message is in Reply To:
  RE: Discontinuous motion.
 
Try looking at the mechanisms at (URL) 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: (...) (25 years ago, 2-Apr-02, to lugnet.robotics)

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