Subject:
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Re: Pawl and rachet?
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Newsgroups:
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lugnet.robotics
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Date:
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Thu, 26 Oct 2000 20:22:08 GMT
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Viewed:
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633 times
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Hello,
I designed just such a drive, using worm gears instead of ratchets. It
does, unfortunately, take a tiny amout of time to shift between moving
forward and spinning in place. Perhaps it will meet your needs anyway.
The relevant images are steps 1-11 in the Minerva 1.5 building
instructions, which start here:
http://www.oreilly.com/catalog/lmstorms/building/minerva1.5/StepsA.html
The basic idea is that the motor drives (via a pulley band) two parallel
shafts with worm gears. One worm gear is fixed, the other one can slide.
Drive the motor one way and the worms drive 8t gears to the axles,
producing forward motion. Drive the motor the other way and the loose
worm gear slides to a second 8t gear, reversing the direction of one of
the axles, and the robot spins in place.
I hope this helps.
Regards,
Jonathan
Ulfr Fenris wrote:
>
> Hello everybody again -- thank you all for the respones, sorry I haven't
> gotten back to some of you who emailed me privately, I've been swamped
> with work. I had some great lego sets recommended to me and I'm trying to
> find out where I can acquire those now.
>
> But I do have another quick question... Has anyone created a sucessful
> racheting mechanism using technic/regular lego? I'm working on a
> one-motor differential drive that works akin to one I saw on Lego's website,
> but is improved because instead of one wheel dragging while turning, they
> both rotate in opposite directions for true turn-in-place ability.
> However, I'm having some difficulty in arranging a method to make one set
> of gears turn in only one direction. I've tried the hanging rachet shown
> on Lego's website
> (http://mindstorms.lego.com/tipstricks/build/master/differential.asp),
> but it's very quirky -- it sometimes doesn't catch immediately and
> therefore my wheel base rolls forward before turning. I've tried adding a
> rubber band around the pawl but it produces a nasty clicking sound and
> likely does wear to the gear/pawl. I've surfed around on various websites
> by Lego engineers, and have seen many creative mechanisms, but so far
> nothing that can help me.
>
> Just wondering if anyone else has had this problem and managed to overcome
> it. (I'll have my lego website up Real Soon Now with pics/cad files of my
> designs and 'bots.)
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Message has 1 Reply:
 | | Re: Pawl and rachet? -- slick!
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| Wow, this is very cool, I like the sliding-worngear principle, a neat hack -- and it's x2 more simplier than my design. :) Thanks for the help! (...) (24 years ago, 26-Oct-00, to lugnet.robotics)
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Message is in Reply To:
| | Pawl and rachet?
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| Hello everybody again -- thank you all for the respones, sorry I haven't gotten back to some of you who emailed me privately, I've been swamped with work. I had some great lego sets recommended to me and I'm trying to find out where I can acquire (...) (24 years ago, 26-Oct-00, to lugnet.robotics)
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