Subject:
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RE: Excavator Pics
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Newsgroups:
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lugnet.technic
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Date:
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Wed, 20 Feb 2002 21:29:13 GMT
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Reply-To:
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<william@AVOIDSPAMhoward-family.fsworld.co.uk>
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Viewed:
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4046 times
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> These are great, I like what you've done with the models - it must have
> taken ages to create them in MLCAD and I'm looking forward to viewing the
> models in greater detail when I get home.
I think it actually took longer to ldraw the excavator than to build it -
but I had fun in the process so who cares. I also had to dismantle most of
it in the process so I effectively built it twice.
The excavator started with the boom, then the tracks and then the engine
unit. I had fun with the tracks as I initially designed what I thought was
a neater solution with the new style diff the other way up. However, the
engine unit then proved impossible to build, so I had to take the tracks to
bits and rebuild. When I compared my final gear train with yours it turned
out to be identical - and I'd only used the initial idea of the diff in the
turntable! Perhaps there is only one way to build this drive train!? The
fixing of the axles for the idler tread wheels kept me guessing until I
remembered the 1x2 brick with axle hole from the mindstorms set.
> Interesting that you've replaced
> the four stud long liftarm in the excavator bucket linkage with a five • long
> one; the four long one has a kinematic singularity which is prevented by a
> 1x2 plate attached to the boom, and since you are using studless beams I
> assume that can't be done so easily ;-)
Whoosh! The sound of that going completely over my head. What on earth is
a kinematic singularity? I'm a computer scientist not an engineer (took a
wrong turning at City Uni and ended up in the Comp block and not the Eng
block I think!)
I do know however that the 'bobcat' bucket arm doesn't work as described on
your web site. I now have a load more 1x5, 1x6 and 1x7 liftarms so I may
redo it sometime to get the geometry right. The last thing I did like that
was to build a level-luffing crane in meccano - the maths took longer than
the build!
Must get to the local building site soon with my digital camera as they have
a rather cute 'JCB' there at the moment with a nice front bucket mechanism
and I need something to justify buying 4 more pneumatic mini-cylinders.
William
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Message has 2 Replies:
 | | Re: Excavator Pics
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| (...) Hi all, It's my first post to the group so by way of an introduction I suppose, there are a few pictures at www.brickshelf.com/c...?m=techgrl . Jennifer, correct me if I'm wrong, but isn't a kinematic singularity a point in the motion of a (...) (23 years ago, 21-Feb-02, to lugnet.technic)
| | | Re: Excavator Pics
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| "William Howard" <william@howard-fami...rld.co.uk> wrote in message n (...) the (...) Given the space constraints I certainly couldn't find any other way, and it took me long enough to work out that one. For a long time in fact I had my doubts it (...) (23 years ago, 21-Feb-02, to lugnet.technic)
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Message is in Reply To:
| | Re: Excavator Pics
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| "William Howard" <william@howard-fami...rld.co.uk> wrote in message news:NFBBICINOLKHMIO....co.uk.... (...) taken ages to create them in MLCAD and I'm looking forward to viewing the models in greater detail when I get home. Interesting that you've (...) (23 years ago, 20-Feb-02, to lugnet.technic)
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