Overpass rigidity?

Originally Posted by dlavery

I am going to campaign that one is included in the Kit Of Parts for next year.

-dave



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Dave, you're my hero! If those were in the KOP, we would reach a new level of precision in fabrication! (don't think about that too deeply...)

[Roger]

Ours was built with black pipe with pvc outside it. (Not having looked at the specs carefully, nor looked at the Kickoff structure, I have no idea what it was built to.) It is bouncy, especially during Jumpball, but not too worrisome. We've got enough students that know enough to tell others not to hang from it.

I would think, Dave, that a hanging load is not very likely during a game, but in our limited experience so far I'd be more worried that a robot would push or pull the overpass sideways (such as in hybrid mode when the robot doesn't know better), or even worse one gets tangled in it while driving forward with another pushing along behind. Would the plates holding up the overpass be held down by the carpet enough to resist a wayward robot?

[Kims Robot]

We actually made our full track completely out of PVC (trying to save some money & weight), but when we stood it up it sagged, so we bought some cheaper and lighter electrical conduit 1" diameter to brace the insides. Before putting it in the overpass (with all the pieces glued & or pinned) it seems to hold together pretty well. We ran the robot into it a few times, bounced the trackball against it and several other abusive actions, and it seemed to stay together, so it seems to be a reasonable modification to the design.

[SSMike]

We built an overpass out of PVC to test designs. As Kim said, PVC is cheaper and easier to assemble. We found out that the design isn't as stable or rigid as aluminum or steel, but we mad due. All you would have to do is have two people hold the "legs" of the overpass. When thrown or placed on the overpass, the trackball does cause it to move slightly, which won't happen during an actual competition. That's just something that we will have to take into account.

[Robostang 548]

Originally Posted by Roger

Ours was built with black pipe with pvc outside it. (Not having looked at the specs carefully, nor looked at the Kickoff structure, I have no idea what it was built to.) It is bouncy, especially during Jumpball, but not too worrisome. We've got enough students that know enough to tell others not to hang from it.

We did the pvc with 1" black pipe in the overpass only. Just PVC on the ends as per the basic team plan (no black pipe). We used 1/8" acft cable criss/crossed on the end supports for more firmness. QUESTION: 78inches, is that from the carpet to the top of the over pass pipe, or the bottom of the overpass pipe?. How much "sag" is in the center of the official game overpass?

[EricH]

Originally Posted by Robostang 548

We did the pvc with 1" black pipe in the overpass only. Just PVC on the ends as per the basic team plan (no black pipe). We used 1/8" acft cable criss/crossed on the end supports for more firmness. QUESTION: 78inches, is that from the carpet to the top of the over pass pipe, or the bottom of the overpass pipe?. How much "sag" is in the center of the official game overpass?

Q&A has spoken...Top of the pipes from the carpet is 6.5 feet or 78 inches.