Pneumatic Tubing
 

so i read the whole part about melting the polycord together with a lighter

and i was wondering whether it would work the same using pneumatic tubing

thanks!

Re: Pneumatic Tubing
 

I do not think so, try testing.

Re: Pneumatic Tubing
 

I know 1622 used pneumatic tubing as their belts, I suspect they connected with barbs that were inserted that hold the ends together, but may be wrong.

I'd send them a message.

Re: Pneumatic Tubing
 

how can i get a hold them?

Re: Pneumatic Tubing
 

I can think of a couple of ways...

1) Go to the FIRST website. 1622 is based in Poway, CA and attended San Diego and Las Vegas. Searching through the map icon or going through the regional list will get you a team info page, with a link to their site. If they don't have contact info there, I will be extremely surprised.

2) Go to the CD member list and do an advanced search for team number 1622. With a little bit of care, you should be able to find the more active CD members and get a message to them.

Re: Pneumatic Tubing
 

Yea we used barb fitting to connect our pneumatic tubing together for our conveyor, and they work great. I would recommend using this system over the poly cord because it is very easy to change/shorten if needed.

Re: Pneumatic Tubing
 

If you are going to use it for pneumatics, the answer is NO. You will severely degrade the operating and burst pressure of the tube.

If you plan on using it for belting material, then yes it will work ... but the degraded strength of the joint may fail (IE when you melt polyurethane tubing it gets weaker but will bond together)

Re: Pneumatic Tubing
 

You cannot use heat to "weld" the pneumatic tubing, as the tubing actually expands with heat. But yes, we used barb fittings. The connection created is so strong, that another mentor and I pulled as hard as we could on a link we made, then gave had a student pull as well and only after about 2 minutes of straining we finally got it to pop open.

The joints created by the barbs are very strong.

Re: Pneumatic Tubing
 

3) wait a little while and they'll answer themselves

:P

Re: Pneumatic Tubing
 

is it available say like at home depot or something that id have to order..
should i try plastic fittings or brass/metal fittings

and what size?



is this how they look like?

Re: Pneumatic Tubing
 

and btw
this is just for our side project.. being that our season is over..
our teacher wants us to build a robot with a "ball pick up" mechanism.
and improving our bot is what my grade depends on ahah
so itll be a fun last senior project

thanks guys for helping out!

Re: Pneumatic Tubing
 

That's what a barbed fitting at Home Depot would look like if you were going to use the tubing to carry water or some other liquid. To get the barbs for making conveyor type belts, try someplace like McMaster:

http://www.mcmaster.com/#6567k22/=1a4azx or
http://www.mcmaster.com/#6567k65/=1a4b43

Re: Pneumatic Tubing
 

ok that helps..
but is it something that i have to order?

shipping stuff to hawaii takes a long time..
or is there a way to improvise using maybe.. short bolts..washers..glue even?
after all its not for competition but for my school project hehe
so just as long as the concept will work its fine.

Re: Pneumatic Tubing
 

Considering that I've heated polyurethane tubing to the point where it will bond with itself ... I'd say that you are incorrect here. I also agree with you that barbs are the way to go, for reasons I stated in my earlier post

If you want to experimant a bit:

Take a small piece of threadded rod (with the OD of the rod slightly larger than the ID of the tubing). Heat the tubing to get it soft enough to push over the ends of the rod. This should work, depending on the load you put on it. I'd also suggest you push the tubing so that the 2 ends meet in the center of the rod.

Re: Pneumatic Tubing
 

We're going to have to agree to disagree on that point then, because when we did it the tube expanded and was unusable.

The barbs we used were from McMaster, and are brass. I cannot for the life of me remember the part # but I can find out for you.

Before we were using the barbs, to test the lift system we took #8's, cut the heads off and left about .5 inch, then pressed the ends of the tubes onto the remaining bit. We had pre-drilled the tubes about .70 inches away from where the #8 would be housed within the tube, and used small cable ties through the tubing to cinch it together.

It worked, but was really only a temporary solution in our eyes.

Re: Pneumatic Tubing
 

ok alright ill try all these suggestions

but as for powering the conveyor belt.. i was thinking of using pvc pipe, foam padding or the foam noodles, bike chain, and CIM motors..
would a FP motor be strong enough for the lift?

Re: Pneumatic Tubing
 

We used delrin tubing, wheel tread material, cable ties, and made some hubs so we could direct drive the rollers with Globe Motors.

Re: Pneumatic Tubing
 

A single CIM motor would definitely be strong enough. We're using a single CIM motor through a 2:1 reduction on our ball intake mechanism using timing belt. This method is probably the easiest way possible to make a very fast and reliable ball intake mechanism. Here's some photos of how we did it:





And a photo of the entire intake roller assembly: http://www.team228.org/media/pictures/view/5085

A FP motor would also be strong enough, depending on far geared down it is. On our robot, we made a custom gearbox to power our elevator with a FP, with an overall ~20:1 ratio, which is pretty much about as fast as you can go. (For reference, the stock black plastic FP gearbox from the Kit of Parts has a ratio of 124:1). The gearbox was designed using the gears from the first two stages in a FP gearbox, with an additional 3:2 25-pitch sprocket reduction from the gearbox output to the elevator. Here's some pictures:







But yes, you can use the KoP FP gearbox without any modifications, it'll just be slow. On the other hand, it would be very easy to hoseclamp a piece of PVC onto the plastic output adapter to drive your rollers.

Re: Pneumatic Tubing
 

We made a sort of similar FP gearbox using only one stage of gear reduction, and more chain reduction, for our intake roller. The gearbox is pretty crude, but did not require much in the way of fancy machining...just punching some holes in 1/8" aluminum plate, and reaming the hole for the motor to the right size, and turning a 3/8" hex aluminum shaft so it's round on the ends to fit into bearings. Center to center distance (gear mesh) is sort of critical, but even if it's a bit loose it will still work ok, although it might not last more than one season :)