Subject:
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Re: Pneumatic Arm
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Newsgroups:
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lugnet.technic
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Date:
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Wed, 15 Dec 2004 23:11:23 GMT
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Viewed:
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3442 times
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In lugnet.technic, Ross Crawford wrote:
> In lugnet.technic, Joseph Greene wrote:
> >
> > My answers to Technic Towers O' Power and Orthogonal Bracing:
> > Method 1- Axles, Axle Connectors and Studless:
> >
> > 1 square segment = 4x Constructed as follows Verticals using Axle Connector #2
> > Alternating 90 degrees with Axle 5L between them for vertical posts, Diagonal
> > bracing is acheived using Axle Connector #5s with Axle 6Ls between them.. pin
> > the Connector #2's to the #5's and even without beams it's pretty sturdy..
> > attach 11L studless (or studded) to the proturding 3L pins to further
> > strengthen.
> >
> > http://68.57.255.231/lego/models/GirderTowerSegment.ldr
>
> Hi Joseph,
>
> That construction would be fine if the "beams" are always in compression, but
> because the diagonals all slope the same way in each section, it would be prone
> to twisting failure if you're not careful.
>
> ROSCO
Actually the only problem I encountered was a slight twist weakness in the very
top and very bottom segments and the physical stress limits (vertically) of the
Axles... I didn't actually reinforce it with beams at all.. looked awesome and
handled the torque of the ~2ft boom being spun at the excessive rate of 30 RPM
with a .5lb load... head ended up flying right off... the tower to crane head
connection was lacking it seems...not to mention 30rpm is a touch high for a
tower crane boom with a load at full extension.. I geared it down to about
3-4RPM...
I'm still playing with the geometry to design an even sturdier config...
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Message has 1 Reply:
 | | Re: Pneumatic Arm
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| (...) Yes it is surprisingly sturdy - I even built one with just #12 axles and no diagonal bracing, and it worked very well. But they allowed significant twisting, it wasn't enough to make them fail but I wouldn't like to push it. (URL) (20 years ago, 16-Dec-04, to lugnet.technic)
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Message is in Reply To:
| | Re: Pneumatic Arm
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| (...) That construction would be fine if the "beams" are always in compression, but because the diagonals all slope the same way in each section, it would be prone to twisting failure if you're not careful. ROSCO (20 years ago, 15-Dec-04, to lugnet.technic)
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