Quick help for a gear changing pneumatics system.

[arun4444]

So if I were to put on these ball shifters:

http://www.vexrobotics.com/ball-shifter.html

They use the two following cylinders to change gears
http://www.vexrobotics.com/vexpro/ge.../217-2778.html

What would be the minimal pneumatics circuit I would need?

I think that a compressor is not needed, would need some tubing a solenoid? and what else?

I would greatly appreciate if someone could draw out the simplest circuit required - I am totally new to pneumatics and was thinking what would be required to swap out our gearbox which this one - there is no other pneumatics on the robot.

[Kevin Sevcik]

The minimum pneumatics system you need is shown in Figure 4-11:

Plus one solenoid valve and a Spike relay to control the compressor.

You have to have all of that, though not necessarily on you robot. You're allowed to leave the compressor, Spike, pressure switch, and relief valve off your robot to save weight. Though it has to be powered by your robot when it's recharging your tanks.

On the other hand, are you SURE you want to do this? Swapping in gearboxes and adding an entire pneumatics system is not a trivial change to make. I'd put it at 2-3 hours for a really good team with a plan of attack. It will possibly take even longer if you've never used/mounted the ball shifters before and never worked with pneumatics before. You're likely going to eat up more of your thursday practice time making this change, so you might want to consider whether you're going to get enough benefit from this to make it worth the time, money, and effort.

[Jaxom]

Originally Posted by Kevin Sevcik

You're allowed to leave the compressor, Spike, pressure switch, and relief valve off your robot to save weight.

Can't leave off the relief valve; see R86:
The relief valve must be attached directly to the compressor or attached by legal fittings connected to the compressor output port. If using an off-board compressor, an additional relief valve must be included in the high pressure side of the pneumatic circuit on the ROBOT. If you want to only store 60 psi (why?) you don't need one.

And don't forget that if you move the compressor off-robot you have to have a manual vent valve both on & off the robot.

[protoserge]

Originally Posted by Jaxom

Can't leave off the relief valve; see R86:
The relief valve must be attached directly to the compressor or attached by legal fittings connected to the compressor output port. If using an off-board compressor, an additional relief valve must be included in the high pressure side of the pneumatic circuit on the ROBOT. If you want to only store 60 psi (why?) you don't need one.

And don't forget that if you move the compressor off-robot you have to have a manual vent valve both on & off the robot.

You do not need the relief valve on the robot [if using a 60psi system] if using an off-board compressor (R86). On the newer Viair compressors, it should be physically attached using a legal T-fitting on the output port of the compressor.

OP, here are two diagrams for your minimal required setup. Please note that I combined the compressor, pressure relief valve, and pressure switch in one block for simplicity; only the relief valve and compressor require a direct physical connection.

You can plumb the ouput ports of one solenoid to both shifters in the same circuit (this saves a lot of plumbing and allows you to use one solenoid).

Let me know if you have any additional questions. Again, this is only a guide and may contain unintentional simplifications. Always double check and refer to the rules outlined in 4.1.10 of the manual http://frc-manual.usfirst.org/viewItem/3#4

[Jaxom]

Originally Posted by stinglikeabee

You do not need the relief valve on the robot if using an off-board compressor (R86).

This is not the case...if using an off-board compressor AND you're storing high-pressure air, you need an additional relief valve.

Originally Posted by stinglikeabee

Always double check and refer to the rules outlined in 4.1.10 of the manual http://frc-manual.usfirst.org/viewItem/3#4

I'll copy-n-paste R86 again, this time with emphasis: The relief valve must be attached directly to the compressor or attached by legal fittings connected to the compressor output port. If using an off-board compressor, an additional relief valve must be included in the high pressure side of the pneumatic circuit on the ROBOT.

Do make sure you follow stinglikeabee's advice about the T-fitting if you're using a new compressor. You can't have any tubing between the compressor & the attached relief valve; this was a common problem in Hub City that caused 8 or 10 teams to re-work their pneumatics before getting their inspection sticker.

[protoserge]

Originally Posted by Jaxom

This is not the case...if using an off-board compressor AND you're storing high-pressure air, you need an additional relief valve.



I'll copy-n-paste R86 again, this time with emphasis: The relief valve must be attached directly to the compressor or attached by legal fittings connected to the compressor output port. If using an off-board compressor, an additional relief valve must be included in the high pressure side of the pneumatic circuit on the ROBOT.

Do make sure you follow stinglikeabee's advice about the T-fitting if you're using a new compressor. You can't have any tubing between the compressor & the attached relief valve; this was a common problem in Hub City that caused 8 or 10 teams to re-work their pneumatics before getting their inspection sticker.

Thanks for the clarification. I misread it as "release"