Pneumatic components for double acting cylinder 'gun'

[eponalank]

Hello.

I am looking to create an pneumatic cylinder actuated system that extend the cylinder at high speed when a trigger is pressed, and automatically returns to position once the stroke is completed.

I was thinking of having a 4way trigger valve, and a air chamber connected to a compressor, and a double acting cylinder. However, I believe that using this arrangement, the cylinder would only retract to position when the trigger is released.
Ideally, even if the trigger is kept pressed, it should retract to position AND STOP. So, essentially like a gun.

I've never done pneumatic circuit related things, so I'm not certain where to go with this. I must avoid electrical-pneumatic systems. Ideally it would be completely air logic, oh and portable

Any suggestions?

Kind Regards,

Francesco

 

[1gibson]

Spring loaded return, with rubber bump stop at full extension? Fixed volume charge chamber with separate switch to refill.

Trigger 1(fire) connects charge chamber to piston chamber (spring return)
Trigger 2 (reload) refills charge chamber

 

[eponalank]

Hm I had thought about a spring system, usually they are contained within a single acting cylinder. However, searching through the catalogues there are no cylinders that are compact enough that give quite high forces ~1kN, i guess it's because they're acting against a spring...

Mmm, I'm not sure if a 2-trigger mechanism is the way to go for my project...

Thank you though!

Regards,

Francesco