Next Question - Check Valve

[archiver]

Posted by Josh at 1/20/2001 12:33 PM EST


Engineer on team #419, Rambots, from Wentworth Institute of Technology.



Alright, here's another little bugger of a problem. We are trying to rig up the check valve in the p-new-matt-icks so that we can take the compressor off if it's absolutly necissary. The only problem we are having is that the manual says nothing about how it works. all it says is we have to find a way to "release preasure between the check valve and the compressor." I've tried a whole lot of things but nothing seems to work. i can get them at different preasures, but it STILL doesn't work, whenever i release the rest of the preasure, both sides of the check valve empty out. could it be that i have it in wrong? i followed the diagram, and i have it as follows:
compressor -

[archiver]

Posted by Jason Rudolph at 1/20/2001 3:21 PM EST


Other on team #459, Rampage, from University of Florida/Eastside High School and .


In Reply to: Next Question - Check Valve
Posted by Josh on 1/20/2001 12:33 PM EST:



What you might want to do, is if you are not planning on using the pilot controlled check valve, then you can put that on the input of the air tanks, and put the plug valve on the other side of the pilot valve. Then, use the plug valve to relieve all the pressure in the line, and the pilot valve will keep all the air in the tanks, then just remove everything except the pilot valve, and you should be good to go.

Jason

[archiver]

Posted by JVN at 1/21/2001 1:02 AM EST


Student on team #250, GE Dynamos - Capital District Robotics Team, from Shenendehowa High School and General Electric.


In Reply to: Next Question - Check Valve
Posted by Josh on 1/20/2001 12:33 PM EST:



Josh-

we've been having trouble with the check valves too. They stick sometimes and leave both sides
open. We loosened em up by putting a higher PSI though them and just working em. If that
doesn't work, maybe you should try a large hammer?

You'd think they'd get the p-new-matics right after all this time.

~John #250 (still pissed because we don't have a vacuum generator this year)

[archiver]

Posted by Josh at 1/21/2001 5:57 PM EST


Engineer on team #419, Rambots, from Wentworth Institute of Technology.


In Reply to: Re: Next Question - Check Valve
Posted by JVN on 1/21/2001 1:02 AM EST:



: Josh-

: we've been having trouble with the check valves too. They stick sometimes and leave both sides
: open. We loosened em up by putting a higher PSI though them and just working em. If that
: doesn't work, maybe you should try a large hammer?

: You'd think they'd get the p-new-matics right after all this time.

: ~John #250 (still pissed because we don't have a vacuum generator this year)

What ever would you need a vaccuum generator for?!

Josh
Team 419
"Dude? Dude! Dude"

[archiver]

Posted by Jason Rukes at 1/22/2001 12:17 PM EST


Engineer on team #109, Arial Systems & Libertyville HS, from Libertyville High School and Arial Systems Corp & SEC Design.


In Reply to: Re: Next Question - Check Valve
Posted by Josh on 1/21/2001 5:57 PM EST:



FIRST is allowing teams to "pull" a vaccuum by attaching a hose to the rod end port of an actuator and manually contracting the actuator. Sound complicated?

Just take two pneumatic actuators and connect the rods together with a nut. When one rod extends, the other will contract. Drive one actuator using the one way valve. On the other actuator, connect the port closest to the rod end to your suction cup. When you activate the valve, the first actuator will extend causing the second actuator to retract and pull a vaccuum through the port on the rod end.

Voila! Read Update 4, M22 if you don't believe.

-Jason

[archiver]

Posted by Jim Meyer at 1/22/2001 12:36 PM EST


Engineer on team #67, HOT Team, from Huron Valley Schools and GM Milford Proving Ground.


In Reply to: Pull a vaccuum
Posted by Jason Rukes on 1/22/2001 12:17 PM EST:



Yes you can make a vaccuum using the low side of a mechanically actuated cylinder. The only thing you can do with this vaccuum is use it for a suction cup. Since we don't have two check valves you have a sort of one-shot vaccuum.

The suction cups probably leak a little. The question I have is how much? If a person used the max volume cylinder how long could he hold onto a ball? Just curious if any of the suction cup experienced teams have a feel for this or if anyone has done this test yet?

Thanks

[archiver]

Posted by Andy Baker at 1/22/2001 1:33 PM EST


Engineer on team #45, TechnoKats, from Kokomo High School and Delphi Automotive Systems.


In Reply to: Re: Pull a vaccuum
Posted by Jim Meyer on 1/22/2001 12:36 PM EST:



: Just curious if any of the suction cup experienced teams have a feel for this or if anyone has done this test yet?

I remember seeing teams grab balls via vacuum in '98. I don't remember seeing anyone do it well.

Team 16 held a 3 point ball in place with a vacuum cup, and that worked pretty well.

There were 5-10 teams who would pull vacuum to pick up a ball and then place it in the middle goal, but they were all slow and the mechanism seemed not easy to control.

My advice to any team attempting to pull vacuum to grab a ball: DON'T DO IT.

There are better ways to grab balls. The fact that FIRST is making it difficult for teams to create vacuum is no mistake, in my opinion.

Do yourselves a favor and don't mess with creating vacuum to grab balls.

The real problem here is letting go of the ball... it's not easy. You gotta have another valve to provide a "puff off" that lets you "let go" of the ball. Even if you have a good "puff off", the dang ball is so big that your seal may still not be broken.

Andy B.

[archiver]

Posted by JVN at 1/23/2001 2:09 PM EST


Student on team #250, GE Dynamos - Capital District Robotics Team, from Shenendehowa High School and General Electric.


In Reply to: Re: Next Question - Check Valve
Posted by Josh on 1/21/2001 5:57 PM EST:




: What ever would you need a vaccuum generator for?!

We wanted it to use suction cups...the other methods for creating vacuum aren't practical on our design, a vacuum generator (something we've had in past years) would save us LOTS of trouble...

We have several different suction cups prototyped, they all work great and can pick up both large and small balls with relative ease... they are both on pivot mounts such that the driver can manage to grab a ball everytime without problems... alas... we must put this design back into our metaphorical closet (it's actually more of a cupboard) and wait for another year... back to grippers...


~John #250