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 22:12:16 GMT
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Viewed:
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3297 times
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In lugnet.technic, Philippe Hurbain wrote:
> Hi Kevin,
<snip for bandwidth>
> > Studless beams work well in some applications, and not well in others. As I'm
> > sure you know, I'm a studless beam advocate, but I'm also a studded beam
> > advocate. For compact, lightweight structures, studless beams have an advantage
> > over studded beams. For structures where you need to worry about static
> > stresses and strains (which your arm has especially when fully extended),
> > studded beams abnd plates are superior.
>
> I'm convinced too now... but maybe someone has found (will find) a way to build
> decent studless braced structures?
>
> > Studless beams have much more flexion than studded beams. To overcome the
> > flexion you need to use cross bracing.
>
>
> I had not much trouble in one direction, but couln't find ways to properly
> attach bracing in the orthogonal direction. So the structure was much too
> flexible. Unfortunately I forgot to photograph the studless version before
> dismantling it...
>
> > Did the connections between the beams fail, or did the beams fail themselved?
> > Or was it that the structure twisted?
>
> Twisting was the main problem...
>
> >
> > The structure below shows your typical cross bracing arrangement. You will
> > want cross bracing in all three dimensions.
>
> I did cross bracing, but stud/hole connection is stiffer that hole/pin/hole (to
> place beams end to end) and much stiffer than hole/pin/hole/pin/hole I had to
> use for bracing in one direction :-(
>
> That said, I find myself using more and more studless constructions - the arm
> itself is mainly studless!
>
> Philo
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
The other method would be to use part Technic Pin Joiner Perpendicular Bent'
(44809) in profusion. This would allow Nice orthogonalbracing, but would use a
fortune in beams....
Built a rather spiffy 3' tower crane using method 1.... would've been taller..
but I ran out of #5 and #2 Connectors....
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Message has 1 Reply:
 | | 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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Message is in Reply To:
| | Re: Pneumatic Arm
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| Hi Kevin, (...) Thanks ;o) (...) Here is their source: (URL) (...) I'm convinced too now... but maybe someone has found (will find) a way to build decent studless braced structures? (...) I had not much trouble in one direction, but couln't find (...) (20 years ago, 17-Jul-04, to lugnet.technic)
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