Looking for a hammer type mechanism

Cannons powered by pneumatic pressure (compressed gas) using a valve or other release.
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FighterAce
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I used to have a comfy 80mm of space behind my schrader pilot valve so fitting a striker mechanism was not a problem... but after a redesign and replacement of the fittings with PN50 rated stuff I was left with only 14mm behind the piston stem.

Now I need some sort of mechanism that will fit in this space...

Image

The rifle itself will be a bulpup piston rifle so if you look at the pic, the trigger would be somewhere far to the left and my shoulder behind about 5mm of wood to the right. Above the pilot area is a cheek rest adjustment knob so theres no room there and below those 80mm is a pressure gauge.

At 50bar the push button valve requires about 120N of force to open.
I guess "hammer mechanism" is not really a valid name because I want the hammer to just push on the valve stem, not strike it at some velocity. This cuts down on noise, vibration and it shouldn't deform the aluminum valve stem after just a couple of shots.

Any ideas?

EDIT

I forgot to mention its supposed to be a spring driven mech... thats why I'm having trouble with it. A direct link between the trigger and some lever would be a lot simpler but I'm going for consistency on this project.
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jackssmirkingrevenge
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How about a hydraulic system? Here's acrude iteration of the idea.
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That would be almost the same as direct link method... depending on the speed of the trigger pull the valve opening time would vary and this is exactly what I'm trying to avoid.

It doesn't really have an advantage in my application since I have a clear path to the trigger guard.
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You don't have enough room for a striker and any amount of travel behind the valve.

Maybe a lever behind the valve and an inline strker below the valve hitting said lever? Light spring on the lever to maintain it's position....
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Gippeto wrote:Maybe a lever behind the valve and an inline strker below the valve hitting said lever?


Or have the main spring attached to the lever itself and have a sear hold it in place... but such a sear would need a trigger press coming from the back. Thats something I can't pull off in a bulpup with any of the mechanisms I'm familiar with.
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Like this quick 2 min job
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Something like that (sorry i made it in 2 minutes)
Something like that (sorry i made it in 2 minutes)
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Where's my Chuck key?
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If the trigger was facing that way I wouldn't be asking for help :D

I think I described it well enough... but heres some perspective on my dimension drawing anyways.

Image


And just for the heck of it... this is what I meant in my earlier post...

Image

Keeping it simple :wink:
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FighterAce wrote:Keeping it simple :wink:
Yes but the problem is when you press the trigger, unable to reset sear, not enough mass to open the valve, if spring was strong enough you would just get 1 big hiss of air,
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Your looking for this then
Your looking for this then
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FighterAce wrote:If the trigger was facing that way I wouldn't be asking for help :D
Personally I find that statement truly ignorant. Gives me the impression that you have a bad attitude. :roll:


Alrighty then...have fun.
Last edited by Gippeto on Sun Jul 01, 2012 1:36 am, edited 1 time in total.
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Goats spudz wrote:Yes but the problem is when you press the trigger, unable to reset sear, not enough mass to open the valve, if spring was strong enough you would just get 1 big hiss of air,
Well... the sear could be reset with a spring and the whole mechanism with a reset rod mounted somewhere on the lever. Mass is not an issue if the spring would act directly on the lever - maintaining my "no velocity" requirement.

1 hiss of air is all I'm looking for and a manual reset is not a problem :wink:
Gippeto wrote: Personally I find that statement truly ignorant. Gives me the impression that you have a bad attitude. :roll:
I'll take ignorant as a fact rather than an insult since I'm genuinely unaware of ways to redirect forces 180° from its origin... but bad attitude? For me thats posting in a non constructive, insultive manner.

Don't get me wrong... I'm thankful for the replies but please stick to the topic and its guidelines.
Gippeto wrote: Clear as mud? :roll:
Indeed :roll:
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Crna Legija
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FighterAce wrote: 1 hiss of air is all I'm looking for and a manual reset is not a problem :wink:
So do you want semi or just one shot?
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I didn't even think of that... no I'm not trying to go semi.

This is what I managed to come up with...

Image

Pivot points are red and the reset bar is yellow.

Its still got a major problem of high leverage ratio which means I need a strong spring and the trigger pull is hard to adjust due to lack of space... I don't think I've got it yet :?
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The steadiness of hand, the acuity of vision and finally
the art of knowing how to make the rifle an extension of the
body all equate to the ultimate synthesis of man and machine.”
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Crna Legija
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why not just open it with the rod movement no spring no need to a respect bar.
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Crna Legija wrote:why not just open it with the rod movement no spring no need to a respect bar.
I already answered you...
FighterAce wrote: I forgot to mention its supposed to be a spring driven mech... thats why I'm having trouble with it. A direct link between the trigger and some lever would be a lot simpler but I'm going for consistency on this project.
FighterAce wrote:That would be almost the same as direct link method... depending on the speed of the trigger pull the valve opening time would vary and this is exactly what I'm trying to avoid.
“The combined synergy of a man and rifle is matchless.
The steadiness of hand, the acuity of vision and finally
the art of knowing how to make the rifle an extension of the
body all equate to the ultimate synthesis of man and machine.”
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