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Subject: 
Re: Vehicle with square wheels
Newsgroups: 
lugnet.robotics
Date: 
Thu, 8 Dec 2005 14:40:53 GMT
Viewed: 
1058 times
  
Hi,

I am not sure about the crown gears - looking at them, the crowns
teeth overhand a central bush which attaches to the axle. Putting them
head to head would not work as this central axle honnetion would
prevent the teeth from meshing. However - you might be able to acheive
the same result by having a toothed half-bush as mentioned below. My
only concern is that those may not take a lot of torque. I just get
horrible visions of teeth being stripped off the half-bushes. Maybe
this could be acheieved with a housing, with four sets of two pinions
at 90 degrees - meaning you still get the original direction. The only
problem there is you are still contending with the gear slack/take up
and will not get a completely smooth transference.

--
Danny Staple MBCS
OrionRobots
http://orionrobots.co.uk
(Full contact details available through website)


On 07/12/05, steve <lego-robotics@crynwr.com> wrote:
Jordan Bradford wrote:
I saw this linked on Slashdot:

<http://www.prweb.com/releases/2005/12/prweb316686.htm>

I liked it too.

I think I'll try building one of these, if I can get the offset angle to
work.
It's 1/4 of 90 degrees, according to the article.

My first thought was also of a Lego solution.  I also got stuck at the
point where I'd have to have plates at 22.5 degree offsets - however,
I think I have an elegant solution that I came up with on the drive
home this evening:

I think it's possible by taking two axles with a crown gear on the end
of each.  Then you can mesh the two gears at any angle you choose to
make (in effect) a long axle with the two '+' cross-sections of the ends
aligned at almost any angle.

You have to finagle some kind of U-shaped clamp to hold the gears
together - but that's easy.

The way this vehicle is set up, it only moves in a straight line.
How might one steer it? Shifting the center of gravity? Disconnecting
one of the wheels from the others temporarily?

The developer claims he has some ideas for steering...no mention of what
they are though.

You can't disconnect a wheel because you'd lose the 22.5 degree offset
to the other wheels and the whole vehicle would come to a permenant
halt.

Maybe you could accellerate the rotating weight as it passes down
one side of the vehicle and slow it down as it goes down the other
side.

Perhaps you just use a huge gyroscopic flywheel to steer with.




Message has 2 Replies:
  Re: Vehicle with square wheels
 
(...) The crown gear has another drawback: its 24 teeth allows 15° or 30° offsets, not 22.5°... Philo (19 years ago, 8-Dec-05, to lugnet.robotics)
  Re: Vehicle with square wheels
 
(...) Yeah - you're right. :-( (19 years ago, 8-Dec-05, to lugnet.robotics)

Message is in Reply To:
  Re: Vehicle with square wheels
 
(...) I liked it too. (...) My first thought was also of a Lego solution. I also got stuck at the point where I'd have to have plates at 22.5 degree offsets - however, I think I have an elegant solution that I came up with on the drive home this (...) (19 years ago, 7-Dec-05, to lugnet.robotics)

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