Subject:
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Re: building thicker technic axles
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Newsgroups:
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lugnet.technic
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Date:
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Tue, 27 Nov 2001 23:20:55 GMT
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Viewed:
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1820 times
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In lugnet.technic, Thomas Avery writes:
> In lugnet.technic, Mark-Jan Bastian writes:
> > Hello,
> >
> > When I see those very big cranes, I wonder how the pivoting points
> > at the bottom of the large booms can hold it out. Are two or more
> > beams with a technic axle enough to handle the enormous force ?
> >
> > I was wondering if it's possible to build thicker axles from lego,
> > for example, using 2x2 round bricks with axles through them, supported
> > by plates with holes and beams on the side.
> >
> > The 2x2 round bricks can then be supported by round corner bricks:
> >
> > http://guide.lugnet.com/partsref/search.cgi?q=corner+round
> >
> > These corner bricks have to be mounted sideways, and supported
> > by sideway-mounted plates. At least 4 corner pieces are needed to
> > contain a 2x2 round brick. A plate-contruction around the corner
> > pieces is needed to make it all solid. The corner stones should be
> > supported by bricks to the sides and underneath it.
> >
> > Not very usual construction, but maybe worth to experiment with.
> > I don't have any round corner stones, but have seen them in
> > 60..70's lego sets a long time ago.
> >
> > Will this idea work ?
> >
> > Mark-Jan
>
> Probably, but I think an easier solution is to have multiple shearing planes
> on your axle (a normal Technic axle). You can kind of see this idea in my crane:
> http://www.texbrick.com/creations/crawler_crane/crawler/cwl5.html
>
> I don't know how much shear force an axle can take, but I know it's quite a
> bit. I've never tested one to failure, but I'd bet it's many 10's of
> kilograms (20... 30?). If you spread out the shear force on multiple planes
> of failure (potential failure, that is ;-) then the shear capacity of your
> axle is greatly increased.
>
> TJ
One thing I noticed about Technic Axles is that they seem to have a bit of
rational flex. You have to have something with a bit of mass being rotated about
the axle to notice it. Look at my znap/technic ferris wheel here ...
<http://www.brickshelf.com/cgi-bin/gallery.cgi?f=6513>
The center pivot is a pair of 12L Technic Axles with some zanp parts for the
load bearing. I have noticed that if I stop the motor abruptly, the mass of the
ferris wheel tries to keep turning and the axle flexs a little ( ~5-deg ) and
then recovers back to the correct spot.
Ray
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Message has 1 Reply:
 | | Re: building thicker technic axles
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| (...) same thing on the helicoptor rotor I've made. To counter this I made a 'one-direction'-drive that 'slipped' when the motor stooped. See (URL) (fifth item in list) and (URL) the axle driving the rotor also had to bee strengthened. I put an axle (...) (25 years ago, 29-Nov-01, to lugnet.technic)
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Message is in Reply To:
| | Re: building thicker technic axles
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| (...) Probably, but I think an easier solution is to have multiple shearing planes on your axle (a normal Technic axle). You can kind of see this idea in my crane: (URL) don't know how much shear force an axle can take, but I know it's quite a bit. (...) (25 years ago, 27-Nov-01, to lugnet.technic)
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