Pnuematics trade at Nats

[davey_c]

Team 449 is looking for a small pnuematics cylinder, with the shortest stroke you can find. We are willing to trade a really big cylinder for it. I think you'll get the best deal, you give us a tiny cylinder, we'll give you a big one. Or a medium sized one, if that's what you really want.

Anyway we just want to know who to talk to when we get to Atlanta to trade for a small cylinder. Post if you have an extra one.

[Paradox1350]

We have the 1 REALLY small actuator. It has the smallest bore, and the smallest stroke that was available from Bimba. I believe it's a 3/4" bore, 2" stroke actuator. Is that what you are looking for?

We have discussed using it for something else, but that would be a WHILE after nationals. I believe we would need something like it in teh fall, if I'm not mistaken. But of course the weight limit is no longer in effect then, so I guess we could use a different actuator or figure out a different method . . . Not important.

Point is, is that the size you need?

[Joe Ross]

We have some large bore, small stroke cylinders. Let me know if that is what you are looking for.

[davey_c]

I guess I can be a little more specific. We're looking for medium bore, smallest stroke. The important thing is the smalls stroke, around 2 to 4 inches. The bore should be about 1.5 inches.

This cylinder will be attached to a skid which will push down to lift up two wheels of the robot to get rid of traction while turning. We're using the pnuematic tires, and they grip so much that we bounce when turning. Our drivers have come up with some creative techniques to work around this, and this system may not be used at all, but I'd like to keep the option open.

Thanks for your help.

[Paradox1350]

Something much simpler and lighter that a lot of teams have been using: pool hose. You can get it at any Home Depot, Lowe's, or other hardware stores. It's cheap, simple to put on, and lightweight. Pool hose is, I guess you could call it, threaded. You know, the hard plastic hose that is threaded and has, I'd say, 4 threads per inch? Maybe less? It has a diameter of about 2 inches, I think? IT's the type of hose that you would use for a pool cleaner-vaccuum -thing, or for a septic tank (we actaully used septic-tank hose). Basically, you cut a length that is enough to cover the entire circumferance of the wheel, then cut a slit down the entire length (or cut a slice out. We did the slit, but two even cuts so that you take out a slice is probably better) and then ziptie it into place over the tire. (If you can find pictures of #69 Team Hyper's bot, they use the stuff on their wheels. We actually found out about it from them and #467 (Duct Tape Bandits) up at a scrimage the Saturday before ship)

Why does it work?

The threads are perpendicular to the side of the bot. In forward motion, they grip. The threads grip the ground. HOWEVER, side to side, the pool hose slips. So forward, you will have a lot of traction, but when turning, you will have very little. It solves the bouncing.

We use the 12 inch pneumatic wheels in the kit. We put the pool hose on the front tires, and left the back bare, and have not had a traction problem since. It was simple, lightweight, effective, and foolproof. I HIGHLY reccomend it. If you have any further questions, feel free to PM me.

[Max Lobovsky]

Have you tried any other coverings? how did pool hose fair relative to them? We used scored zipties wrapped radially until a judge told us (but not other teams, apparently) to take them off at Annapolis (even though we had ran all through Trenton with no field damage problems with them)

[ReggieB]

Yes, we tried zip ties. And yes we were told to take them off at annapolis. We didnt even have them scored, they were smoothe. Anyway we were thinking about using some cable management tubing (very similar stuff--even has the cut built in), but werent sure if you could attach it w/o zip ties. We'll have to play around with stuff when we get there.
While we are on the topic of trading stuff--we might need another smallest-bore short stroke, although not as short, for our 2x system. Not sure on the details yet, more to come.

Also, we might want some 1" 80-20 extrusion drop in nuts, 1/4-20. If you have some just stop by 449 at atlanta. We thought we had some, but turns out we had 3cm not 1" stock from before this year.

Dont all post saying "I've got that....", just bring some by when we are in atlanta. we dont need to waste other peoples time with a back-and-forth with the stuff.

Thanks for all your help!

[Wetzel]

Originally Posted by maxlobovsky

Have you tried any other coverings? how did pool hose fair relative to them? We used scored zipties wrapped radially until a judge told us (but not other teams, apparently) to take them off at Annapolis (even though we had ran all through Trenton with no field damage problems with them)

Other teams covered them with pnumatic tubing.


Wetzel

[Paradox1350]

We didn't try other coverings simply because the sump-pump hose worked perfectly. We haven't had a traction problem since, and because the zip-ties fit into the grooves of the hose, they don't even touch the ground. Thus, no damage to the field.