Subject:
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Working automatic transmission!
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Newsgroups:
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lugnet.robotics
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Date:
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Wed, 25 Nov 1998 07:43:23 GMT
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Original-From:
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Andrew Carol <AECAROL@spamcakeIX.NETCOM.COM>
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Viewed:
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1978 times
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I took Dave Forrest's automatic transmission challenge and built a working
model out of basic technic. It determines which gear to use strictly based
on the load being driven.
I put a shock-absorber spring over an axle next to a screw. The screw
drives first gear until there is too much of a load. It then is able to
squeeze the spring and slide up to another gear which is second gear.
This leaves me with one axle which turns as first gear, and a second which
turns as second gear. Only one would turn at a time, depending on where the
screw is.
I combine them with a differential. Of course when second gear is engaged,
and there is a load, the
first gear side of the differential would like to free spin in reverse. I
simply added a ratchet and now it works!
It starts in first gear. As I add to the load (by holding the output wheel
with my finger!), the screw eventually slides over to second gear which
greatly increases the power (I can't hold it anymore!). When I loosen my
hold on the wheel, the spring forces the screw back to first gear.
* <- Large gear on differential body drives output.
*-R[]-* <- R = ratchet, [] = differential
^ <- 1st gear axle has lg gear which drives med gear as
differential input 1.
^ <- 2nd gear axle has med gear which drives med gear as
differential input 2.
* * <- small gears. Left drives 1st gear axle, right drives
2nd gear axle.
-#-//////SSSSS#-M <- /// = screw, SSS = spring, M = motor (geared down a
bit)
It's fairly compact and works like a charm! I hope to take some pictures in
the next few days.
---- Andrew
> > > 2 speed automatic transmission challenge
> > > Based on this design, http://www.sonic.net/~rci/transmission.htm
> > > can you come up with a 2 speed automatic transmission.
> > > I did.
>
> * RCX based solution to the automatic transmission challenge snipped. *
>
> > When it goes uphil, the weighted pendulum makes contact with
> > the sensor, this causes the motor to reverse direction and
> > shift the transmission to low gear. when it reaches level ground,
> > the pendulum swings forware, moving off the sensor, and this
> > causes the motor to change directions, thus shifting to HIGH.
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Message has 1 Reply:
 | | Re: Working automatic transmission!
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| Andrew Carol writes: > * <- Large gear on differential body drives output. > *-R[]-* <- R = ratchet, [] = differential > ^ <- 1st gear axle has lg gear which drives med gear as > differential input 1. > ^ <- 2nd gear axle has med gear which drives (...) (26 years ago, 25-Nov-98, to lugnet.robotics)
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