Re: [OT] Mecha - coming to a forest near you!

At 1:04 PM +0900 6/21/02, Edward Lipsett wrote:
>
>Even with full seals, the design either (1) has a large number of
joints,
>one for each degree of freedom on each leg or (2) has a complex joint
with
>multiple degrees of freedom. Treads are essentially glorified rollers,
and
>while you can drop a track, the tread mechanism itself is relatively
tough

Rollers with lots of moving parts regardless.

>and adjustment-free, because it is constrained in a very
narrowly-defined
>motion path, with only two directions of travel both on the same axis.
A leg
>mechanism, no matter how they design it, is going to be a nightmare of
>components with enormous fluctuations in loading. I'd love to be on the
>design team, but I'd really, really hate to have to deliver one on a
>schedule.

Well, the difference is that the treads are very good at getting 
their parts all gummed up with muck, dirt, and other things that 
aren't friendly to bearings. Each track has road wheels, springs and 
other items that all have bearings and seals to pay attention to. The 
tracks themselves are also an issue unless you have rubber band 
tracks. Lots of things to maintain. Lots of grease nipples. I can see 
building a very well protected housing around each leg of a walker 
and making it all a sealed system that is much harder to get crud 
into that will cause problems with the bearings in the first place. 3 
layers of seals would be much better.
-- 
--
Ryan Gill			  rmgill@mindspring.com
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