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Auto piston valve + realoading system (BB cannon example)

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Auto piston valve + realoading system (BB cannon example)

Unread postAuthor: al-xg » Fri Oct 26, 2007 1:07 pm

Ok, first off, the automatic piston valve:
It uses the pop-off valve idea, but in a chamber filling version.
A spring keeps the piston(or membrane) foreward while air leaks in and the pop-off valve dumps the air in the pilot port at the set pressure.
It has a slower cycle than some of the other full auto or pulsed air design but is more efficiant than the normal pop-off valve design because of the smaller pilot volume and less air is lost while the valve reseals( and it is lost down the barrel instead, making a nicer vapour trail ? :) )


For use with the auto piston valve, or any other full or semi-auto system, this realoading system, uses a small pneumatic ram connected to the chamber.
The ammo is loaded between shots, possibly making it more reliable than
most blow forward and blowback designs.
I can also be combined with a simple shell ejecting system.
The bolt only moves back once the pressure in the chamber has dropped enough so there a fewer leaks.
There is also less obstruction to the air flow, the smallest inside diametre in this system is the same size as the ammo; so better flow and less resitance and therefore less chance of it blowing apart because of the amount the air dumped by a good piston valve.
It also enables one to add moving exterior parts (such as a cocking lever ?) making the action look like gas blowback systems.

Ok here are the pictures:
Image
Image
Image

1- Is a basic piston, but it has to let air bleed from the chamber to the pilot port. A few simple modifications could reduce air loss some more.
2- Is a pop-off valve, set to what ever pressure is wanted. (A 70psi pop-off and a ~10cm barrel is all that would be needed for airsoft...)
3- Is connected to any kind of basic valve (ball valve, blow gun, slide valve...)
A regulated air/gas source would be best, a bigger chamber with a regulator, a comrpessor, HPA, CO2 or any regulated gas.
4- Is a small part connecting the inner loading tube to the ram. The loading tube is just the same size as the one used for the barrel, if cut with a pipe cutter leave the end bend inwards for better loading.
5- Is a cocking handle but could be anything that need to move after a shot.
6- Is optional, but usefull. It's some kind of hop-up or o-ring to stop the BBs from rolling out of the barrel and/or give spin to the projectile.

This design is good for people looking for a slower rate of fire that Strafers but more powerfull, consuming less air and with a mechanical action and sound. (closer to the Dakka dakka anyway)

I might build this one day but I don't have the time at the moment, it's posted on here so anyone who would like to try it out can.
I have started a larger calibre semi-auto version.
It shoots ~14mm (.55cal) epoxy rifled bullets. (or anything that size...)
It runs with a 3/4" QEV so the ram isn't embeded, it is jsut part of the chamber.
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Last edited by al-xg on Fri Oct 26, 2007 4:35 pm, edited 5 times in total.
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Unread postAuthor: battlemonkey » Fri Oct 26, 2007 1:18 pm

very nice. i will have to try it once i have finished my current gun.
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Last edited by battlemonkey on Fri Oct 26, 2007 1:23 pm, edited 1 time in total.
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Unread postAuthor: jackssmirkingrevenge » Fri Oct 26, 2007 1:22 pm

The ram linked to the chamber is very innovative and merits further development in the world of small calibre semi/autos, very good thinking :)
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Unread postAuthor: al-xg » Fri Oct 26, 2007 1:26 pm

OK, the pneumatic ram (embedded or not in the chamber) pushes the rod foreward when the chamber is pressurised.
It is connected to the loading tube and is spring loaded back.

->When the firing valve is pressed, air fills the chamber, and it moves foreward. It pushes the ammo into the barrel and blocks off the magazine feed.
->When the piston valve fires, all the air is dumped down the barrel, and once pressure is low enough the spring pushes it back letting a new round pop up from the magazine.
And the whole process starts again when the pop-off valve then piston reseal.
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Unread postAuthor: battlemonkey » Fri Oct 26, 2007 1:35 pm

That is the most inovative idea ive seen in awhile. Up til now people have just been playing around with the same ideas but yours is very new to me. BTW your a great drawer
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Unread postAuthor: jackssmirkingrevenge » Fri Oct 26, 2007 1:40 pm

BTW your a great drawer


Looks like more of a cupboard to me :roll:

:D
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Unread postAuthor: iPaintball » Fri Oct 26, 2007 1:50 pm

I love the loading system idea, and as far as I know it has not been done before. I love your drawings too. Very detailed and realistic!
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Unread postAuthor: LikimysCrotchus5 » Fri Oct 26, 2007 2:02 pm

Well it looks like we know who did thier homework :idea: Great, excellent design, this would take me a long time to design. Tell us when you get your supplies. This would be something as good as clides GB cannon or even better. :D Would you use pvc to build it?
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Unread postAuthor: al-xg » Fri Oct 26, 2007 2:18 pm

Im from europe, so copper is easier to get (and i can get most of it free).
The main problem with semi-auto or full-auto is that copper is quite soft, and makes it quite hard to work with for small parts.
Although if it doesnt bend stright awy it should get harder with the vibrations the more it is used.

Most of this is just reusing Clide's or Jackssmirkingrevenge's and all the other people who have come up with new ideas, ...ideas :)

But its good for once that this hasn't been heard off yet(i hope), reinventing things, gets disapointing ;)
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Unread postAuthor: Tom » Fri Oct 26, 2007 2:58 pm

Looks like a very good idea :!: Do you draw manga?
GR.Tom
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Unread postAuthor: al-xg » Fri Oct 26, 2007 3:07 pm

No, haven't tried yet... i don't actualy draw properly that much. Just tends to be scribbles on the edges of pages (often lessons :oops: ). But i like drawing...
I've just noticed a few mistakes though, the top drawing wouldn't even work :roll: oh well it still shows the general idea...
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Unread postAuthor: spanerman » Fri Oct 26, 2007 3:15 pm

nice to see you got this posted up :o the drawing look amzing and the design is very good :twisted: all it needs is for someone to make it.....hint hint JSR :wink:
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Unread postAuthor: jackssmirkingrevenge » Fri Oct 26, 2007 4:46 pm

spanerman wrote:...hint hint JSR :wink:


In the "hmmm..." pondering stage as we speak ;)
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Unread postAuthor: ALIHISGREAT » Fri Oct 26, 2007 5:06 pm

a very nice design, but how is the pop-off reset? and i know what i would do with it, i would give it a long barrel and make it pump/bolt action for the shotty/sniper look :twisted:
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Unread postAuthor: jackssmirkingrevenge » Fri Oct 26, 2007 5:08 pm

but how is the pop-off reset?


It resets itself once the pressure drops below a certain level

pump/bolt action for the shotty/sniper look


Er... It's an autoloader, therefore it doesn't need a bolt or pump action :P :D
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