Subject:
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Re: gear differential
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Newsgroups:
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lugnet.robotics
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Date:
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Thu, 19 Nov 1998 16:43:51 GMT
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Original-From:
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Alex Wetmore <alex@phred./stopspammers/org>
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Viewed:
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1882 times
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From: stephen p spackman <stephen@acm.org>
> Actually I'm still proud of it - I built an all-LEGO automatic
> transmission.
>
> Only *how* it worked was by using pairs of the little crown bushings
> (seemingly defunct as of this year?) as clutches, a pair at each end of
> an axle (adjusted very *very* carefully to get exactly zero clearance
> when turning free) with a worm gear thrusting against a rubber band to
> measure the applied force (and of course the usual 2:2 and 3:1 gear
> ratios around the two ends)....
Its easier to build transmissions using the freewheels 16t gear (its a 16t
with a smooth hole in the middle, so it spins on axles). If you search for
"technic transmission lego" on http://www.dejanews.com you can see a couple
of different designs. The one that I've built (from an article that I found
there) had 3 speeds (direct, 3/4, and 3/1).
Here is the article (you'll want a fixed size font for this)
I recently got 5 packs of 'gear wheels' from S@H. Each pack includes a
*very* useful little gear. I've never seen this particular gear in any
set, and I was wondering what it was for. It's number 6542, has 16 teeth,
and is unusual because of it's colour- dark grey rather than the usual
light grey. I have been wanting a similar gear for some time, and now
I have 5 of them! What makes it so special is it doesn't attach to the
shaft- it just spins free. Also, it has a place where you can mechanically
attach other legos or 2 of the gears can fit together.
So far, I have used it in two diffrent projects. The first is a real
working clock. Yes, it keeps time. It has a pendulum that swings
back and forth, it has an automatic electric winder (it's spring
driven), and concentric minute/ hour hands. The gear came in handy for
the concentric minute/ hour hand arrangement.
The other project I whipped up tonight was a very cool transmission.
It has selectable ratios 3,9, and 27. (from the motor) Reverse is
coming, but not implemented yet. Here it is:
# - Z16 gear
$ - funky 16-tooth gear (#6542)
% - Z8 gear
* - Z24 gear
! - Shaft
M - motor
! !
! ! %*****
! ! ! !
### ! $$$###
#########
### ! $$$###
! ! ! !
! !*****%
!
!
%*****
MMMMM
MMMMM
MMMMM
The 1st shaft on the left is the output shaft.
The 2nd shaft on the left is the shifter shaft, move it up/down to adjust
speed.
Sorry the drawing wasn't clear, but ASCII doesn't lend itself well to lego
drawing! ;-)
alex
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Message has 1 Reply:
 | | RE: gear differential
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| (...) <snip> Those freewheeling gears are really cool. I just bought the Technic Shuttle and it comes with a whole lot of them It uses them in quite a complex gearbox to drive all of the operations of a single motor. If you take another look at the (...) (26 years ago, 19-Nov-98, to lugnet.robotics)
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