Repeating Hammer Valve Design

Cannons powered by pneumatic pressure (compressed gas) using a valve or other release.
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ALIHISGREAT
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could a heavier hammer slow down the rate of fire? it would travel slower but it would also release more air...
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SubsonicSpud
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ALIHISGREAT wrote:could a heavier hammer slow down the rate of fire? it would travel slower but it would also release more air...
A heavier hammer dose slow it down a small amount, but I cannot make it much heavier as it is about 80% lead already, plus I think it would self destruct if there was any more weight in it. I might try a small vent in the front of the hammer to make the piston less efficient.

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jackssmirkingrevenge
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SubsonicSpud wrote:A heavier hammer dose slow it down a small amount, but I cannot make it much heavier as it is about 80% lead already, plus I think it would self destruct if there was any more weight in it. I might try a small vent in the front of the hammer to make the piston less efficient.
If I understood correctly, the spring keeps the pilot valve open even when at rest. Why not reduce the spring stength and actually have to cock the hammer before firing so it opens by the hammer's momentum (which is after all how hammer valves usually work) instead of doing it by opening the air flow?
ALIHISGREAT wrote:spudfiles has gone repeater mad!
Can't be a bad thing, there's only so many times you can enjoy firing potatoes :P
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SubsonicSpud
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jackssmirkingrevenge wrote:
SubsonicSpud wrote:A heavier hammer dose slow it down a small amount, but I cannot make it much heavier as it is about 80% lead already, plus I think it would self destruct if there was any more weight in it. I might try a small vent in the front of the hammer to make the piston less efficient.
If I understood correctly, the spring keeps the pilot valve open even when at rest. Why not reduce the spring stength and actually have to cock the hammer before firing so it opens by the hammer's momentum (which is after all how hammer valves usually work) instead of doing it by opening the air flow?
ALIHISGREAT wrote:spudfiles has gone repeater mad!
Can't be a bad thing, there's only so many times you can enjoy firing potatoes :P
The spring did hold the valve open originally as in the video, only because it was the only spring i had lying around, i have cut it down since. Did not really change the cycle from what i can tell, just the amplitude of the hammer.
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jackssmirkingrevenge
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SubsonicSpud wrote:The spring did hold the valve open originally as in the video, only because it was the only spring i had lying around, i have cut it down since. Did not really change the cycle from what i can tell, just the amplitude of the hammer.
Interesting. I would try progressively weakening the spring, it looks like it has quite a bit of mass to it won't need to be travelling very fast to knock the schrader open.
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Brian the brain
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You should move back the venthole to get lower ROF...
Gun Freak wrote:
Oh my friggin god stop being so awesome, that thing is pure kick ass. Most innovative and creative pneumatic that the files have ever come by!

Can't ask for a better compliment!!
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SubsonicSpud
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Brian the brain wrote:You should move back the venthole to get lower ROF...
I don't really have a vent hole on it like in the design diagram, the air just vents through the slot that the cocking bolt slides in. I suppose i could try increasing the volume in the area around the schrader, it would cause it to take longer to build up pressure to push the hammer back.
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daniel323
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sorry im just confused..



i saw your design and thought i got the concept but now i am totally confused.. after you actually built it.. I have been searching hammer valves for the past day with no success

could someone please explain?

my understanding was the hammer hit the little stem on the schrader and then the hammer sild back (becasue the airflow coming in) and kept repeating the same process becasue it was being pushed by spring.

EDIT. ok now i have a little more insight.. this design doesnt have a vent that.. makes more sense because i was wondering where all the air was flowing out
Last edited by daniel323 on Mon Apr 06, 2009 10:11 pm, edited 1 time in total.
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jackssmirkingrevenge
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daniel323 wrote:my understanding was the hammer hit the little stem on the schrader and then the hammer sild back (becasue the airflow coming in) and kept repeating the same process becasue it was being pushed by spring.
That is correct as far as I can tell, what didn't you understand?
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daniel323
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ok jsr or anyone

what i didnt get was how the hammer hit the little stem in the first place..

is it becasue the spring pushes the hammer against the schrader initially?
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daniel323 wrote:what I didnt get was how the hammer hit the little stem in the first place...
As below:
SubsonicSpud wrote:
jackssmirkingrevenge wrote:If I understood correctly, the spring keeps the pilot valve open even when at rest.
The spring did hold the valve open originally as in the video, only because it was the only spring I had lying around, I have cut it down since.
;)
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daniel323 wrote:ok jsr or anyone

what i didnt get was how the hammer hit the little stem in the first place..

is it becasue the spring pushes the hammer against the schrader initially?
The way i have it set up at the moment the spring dose not hold the hammer on the schrader valve to start the cycle the hammer needs to be cocked back slightly and released. In the video the spring i was using was a little too long so it was pushed against the schrader, hence the hammer would start cycling as soon as the air supply was turned on.

The cycle is intended to be like this:

The hammer is cocked back against a sear, once the sear is released the spring accelerates the hammer forward. Momentum of the hammer causes it to impact the schrader valve releasing air into the chamber around the schrader. The higher than atmospheric pressure air in this chamber then pushes the hammer back towards the spring until it changes direction and continues on another cycle. this cycle will continue until the sear is released and recaptures the hammer in a cocked position

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daniel323
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ok thanks for clearin everything up

now i fully understand
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