The straps should be strong enough, maybe use two to be sure. Grooving the floor would weaken it and the panels would have to be carefully aligned to make the grooves match up. With the strap, there will be no alignment issues so I think its the simpler solution.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

The arena originally used ratchet straps, which I believe were only used at the Ideas Festival and were lost in the flood. The idea was borrowed from RoboGames. However the ratchet was ugly hanging on the side of the arena.

I like the steel straps. I've used them a lot before. Maybe weld a loop onto the steel angle braces to allow the steel strapping to loop from one side to the other, ratchet it tight and then use Snap-on-Seals to hold it.
http://www.ebay.com.au/itm/19mm-Steel-Snap-on-Seals-for-Steel-Strapping-x1000-pieces/161507809547?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D30374%26meid%3D9e9d85c8bd7140c88fbd7ae8233a7831%26pid%3D100005%26rk%3D2%26rkt%3D6%26sd%3D161491226706&rt=nc
http://www.ebay.com.au/itm/19mm-Steel-Strapping-Crimper-Hand-Tool-Sealer-for-Steel-Straps/161491226706?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D30374%26meid%3Dc58802a622fd4a6cb4eb5effcae68c5b%26pid%3D100005%26rk%3D3%26rkt%3D6%26sd%3D281344441222&rt=nc

Ideally, a horizontal support structure design with location pins like we use for the roof couple be used for the floor. It would only elevate the floor 25-30mm and allow the arena panels to be located into the pins and prevent them moving.

Alternatively, a vertical support just like the roof would provide a raised platform and allow for things like a pit, under arena cable management and potentially arena leveling.

Unfortunately it all adds weight to the arena as a whole and I believe this is an issue for transporting the arena.
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https://www.halfdonethings.com/

Ideally we would separate the outer panels from a raised internal barrier with a rigid structure and floor. However realistically I don't think this is possible due to the issues we already have with weight and just the time needed to construct it before nats.

Steve
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Steven Martin
Twisted Constructions
http://www.botbitz.com

Is there any concern about the high KE spinners and the wall steel?
Some MDF or ply or something over the interior of the panels would give it a decent buffer and save the arena and the spinners (and make dramatic explosions of debris)

I don't know about crimping on the straps, its simple which is great, but it puts the crimp on the inside of the arena (if I'm reading that right) so if anything needs to be done (big hit pops one loose) you need to take the floor up?
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Mechanical engineers build weapons, civil engineers build targets

quote:

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Originally posted by Valen:
Is there any concern about the high KE spinners and the wall steel?
Some MDF or ply or something over the interior of the panels would give it a decent buffer and save the arena and the spinners (and make dramatic explosions of debris)

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Here are two ideas for the straps; I drew the arena floor from memory and not to scale, sorry if its not quite correct. The first option uses the crimps, with a short tail crimped on to the main strap so the tensioning crimp is outside the arena. It will need a hole or slot cut through the channel that aligns the walls and there may have to be a ramp or notch cut in the underside of the floor so that the strap doesn't raise it up:



The 2nd option is to clamp the steel strap with a plate. This would mean less modification to the arena but we would either have no tension (do we really need it?) or the tensioning tool might need some mods.

I like the 2nd option as it looks simpler. Chances are that the tensioning tool can be modded to hold the strap while the clamp screws are tightened.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

I think option B is better as more cuts and stuff in the arena arent ideal. However how do we tension them?

I would like to put a bit of force on the cables so they are held in tight. I would also like to be able to retighten them after say the first day. Just in case something comes loose.

Agree with Aaron about MDF and we have the additional 6mm at the very low level on the arena now. If we have penetration will have to re-evaluate but decimator is the only likely candidate. At this stage.

Steve
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Steven Martin
Twisted Constructions
http://www.botbitz.com

We might not need any tension on the straps - it depends if a bot running into the wall stretches them significantly. If the walls are tight against the floor when the clamps are screwed down, then they can only move away from the floor if the strap stretches or there is accidental slack in the strap. Even a small amount of stretch would be OK, its when the walls bow out 20mm that bots get stuck in the gap.

I don't know how those tensioners work, but we can probably add a base plate or some pins so it latches on to the arena perimeter plate while it pulls & tensions the strap. in the worst case, we make our own tensioner.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

If you change the clamp (and steel) so that the strap comes up through the steel base then straight through the clamp you should be able to directly tension it with an off the shelf tensioning tool by the looks of things.
https://www.youtube.com/watch?v=Skr2cVIyyOg

Means cutting a slot from the edge into the steel then welding the clamp back into its place. I think we will want to tension them just to get the slack out of everything, I don't know if we need the tool though.

made a picture

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Mechanical engineers build weapons, civil engineers build targets

I was thinking that wrapping the strap around the edge of the plate and back into the clamp would add friction and help prevent slipping. Looking at the video, cutting a slot to feed the strap thru makes more sense if we want to tension it. Problem solved .
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Machine up the clamp with an "interesting" shape for positive lock onto the strap?

\/\/\/

Only issue if you kink the strap you can't tighten it again after you clamp it once.

Perhaps just a subtle set of matching grooves? or pins and some lands?
We should be able to CnC up some jaws out of mild.


oh btw, if you are after a grease that can tolerate rain check out boating grease, its great stuff.
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Mechanical engineers build weapons, civil engineers build targets

quote:

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Originally posted by marto:
The trailer is also overloaded. So need to work out how we can lighten the setup.

Steve

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Trailer has already had heavier springs put on it, electric brakes and is dual axel. Not sure if it can be upgraded much more. We are also really limiting our tow vehicles as well.

Will chat to dad and see what he thinks. Might need to use some club funds.

Steve
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Steven Martin
Twisted Constructions
http://www.botbitz.com

Has anyone seen this arena controls post at Sparkfun? https://www.sparkfun.com/news/1874 Looks really interesting - they are using it on an antweight arena but there is no real reason we couldn't apply all the ideas on a larger arena.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion