Pneumatic Ball Puncher

[themccannman]

Originally Posted by Brandon Zalinsky

Mark my words.

One cylinder got our team an undefeated qualifications in 2008. I'm loving your "absolutely not" certainty- our punch prototype shoots 25 feet. I repeat my guarantee- at least one team on Einstein will have a linear pneumatic punch shooter.

The only way you could get a decent shot is if you manually stopped the piston from extending, and allowed the pressure to evacuate form the decompressing side before releasing it. I'm not even sure if that's legal though.

[Wren Hensgen]

With regards to allowing the pressure to evacuate, why bother? Just leave the top of the cylinder disconnected, and allow the weight of the rod to return it to rest when the solenoid is fired.

[arizonafoxx]

I think some people might want to look at some of the soccer kickers from 2010. Many of the kickers that year were surgical tubing assisted by pneumatics. Kicker was drawn back and latched with pneumatics which stretched the surgical tubing. Then the solenoids were actuated in the other direction and then the latch was released. It was discovered that lots of energy was stored and released this way. So I tend to agree that there is a possibility that a punch using pneumatics could end up on Einstein.

[Kevin Sevcik]

Originally Posted by themccannman

The only way you could get a decent shot is if you manually stopped the piston from extending, and allowed the pressure to evacuate form the decompressing side before releasing it. I'm not even sure if that's legal though.

It was legal in 2010 and a fairly popular method of powering kickers.

[jacqlecl772]

well my team original idea was to use pneumatic but we simply could not get the piston to extend fast enough to push the ball far enough. We even called are pneumatic guy to ask him if he had any cylinders that could open with such speed and force but he told us that he could not think of any way to do it. So i would say that to my knowledge there is no way of using pneumatic to shoot the ball in to the high goal, however it may be possible in the low goal.

Your best bet is to prototype some different shooters and pick the best one !

[PVCMike]

I am continuously surprised by the discouraging comments, especially by adults and mentors on this forum. FIRST is about encouraging these students to TRY things, think outside the box, see whats possible, yet this thread is full of the opposite.

There is a big difference between "we have not been able to figure out how to do it." and "it's impossible" or "don't even bother." Let's be constructive not discouraging.

[DELurker]

Originally Posted by theCADguy

Team 20 has prototyped pneumatic system to propel the ball. We had absolutely no luck. The system barely got the ball in the air.

1370 did some testing last night. the 1-1/2" cylinder (1.7 factor) moved too slowly to launch and the 9/16" cylinder (0.2 factor) didn't have enough thrust. The students are interested in splitting the difference and going for a 1-1/16" bore cylinder (0.9 factor), but we would have to get one.

Right now, we're putting air punches on a back burner pending the outcomes of other ideas.

[Sarakiro]

If you are looking at a linear "punch" (actuation), your best bet (if you intend to use pneumatics) will likely be to use a wide bore piston to reset a highly tensioned plunger mechanism on guide or track. Just a thought.

[Al Skierkiewicz]

Brandon et al,
During inspection, launchers may have to demonstrated for "dry firing" to see if they are in fact safe with no ball present. Having no external hard limit for cylinders quite frankly scares me. While the working pressure is only 60 psi, a cylinder can impart quite a bit of force on the piston and the end assy with no system resistance. I have seen enough catastrophic failures to worry about this design choice. Please prototype with extreme safety in mind.

[PVCMike]

Originally Posted by Al Skierkiewicz

Brandon et al,
During inspection, launchers may have to demonstrated for "dry firing" to see if they are in fact safe with no ball present. Having no external hard limit for cylinders quite frankly scares me. While the working pressure is only 60 psi, a cylinder can impart quite a bit of force on the piston and the end assy with no system resistance. I have seen enough catastrophic failures to worry about this design choice. Please prototype with extreme safety in mind.

While a 3/4" cylinder with good flow to it moves pretty quick, and we always make strong efforts to work and design safely, I would be amazed if an unmodified COTS piston operated at less than 50% max psi recommended by the manufacturer (125psi max, operated at 60psi per FIRST rules) failed due to dry firing. This would be a major design flaw by the manufacturer. Now if we dry fired it at 125+ psi many times and it failed that's another thing. We will of course exercise caution but a failure of this type with no other damage or modification seems implausible especially given the reliability of our product manufacturers.

[martin417]

Originally Posted by jacqlecl772

well my team original idea was to use pneumatic but we simply could not get the piston to extend fast enough to push the ball far enough. We even called are pneumatic guy to ask him if he had any cylinders that could open with such speed and force but he told us that he could not think of any way to do it. So i would say that to my knowledge there is no way of using pneumatic to shoot the ball in to the high goal, however it may be possible in the low goal.

Your best bet is to prototype some different shooters and pick the best one !

I can guarantee that it is possible to launch the ball into the high goal using only unassisted pneumatic cylinders. In 2008 we were able to fire the ~8 pound, 40" diameter trackball way farther than would be required for this 2 1/2 pound 24" diameter version

[Al Skierkiewicz]

Originally Posted by PVCMike

While a 3/4" cylinder with good flow to it moves pretty quick, and we always make strong efforts to work and design safely, I would be amazed if an unmodified COTS piston operated at less than 50% max psi recommended by the manufacturer (125psi max, operated at 60psi per FIRST rules) failed due to dry firing.

Mike,
125 psi is the working pressure at which integrity with pressure is guaranteed. It does not relate to mechanical failure of the device with no load.

[themccannman]

Originally Posted by PVCMike

I am continuously surprised by the discouraging comments, especially by adults and mentors on this forum. FIRST is about encouraging these students to TRY things, think outside the box, see whats possible, yet this thread is full of the opposite.

There is a big difference between "we have not been able to figure out how to do it." and "it's impossible" or "don't even bother." Let's be constructive not discouraging.

Most of us aren't trying to discourage students, were trying to save you from wasting your build season. 6 weeks is not enough time to try every possible method and pick your favorite. A large portion of the design process is brainstorming what is feasible and what isn't so you don't waste your time. We will be ready by week 1, and I hope we can get as many other teams as possible ready by then too.

[LH Machinist]

One method of shooting using pneumatics.

[yara92]

Originally Posted by LH Machinist

One method of shooting using pneumatics.

can you Explane how this works