Trigger mechanism for pneumatic gun - design modification

[tromic]

I happened to find one of the videos. There are two videos.

 

[popgun pete]

What about the relatch, the sear tooth will be down with nothing to lift it back up?

 

[tromic]

What about the relatch, the sear tooth will be down with nothing to lift it back up?

It seems not to been finished yet. The left part has some epoxy on it to hold it together. That was just one of the tests. I suppose there is one spring as usual for the right side part..?

 

[popgun pete]

I don't really see any advantage even if it does work, which I doubt as he pulls at an angle on it, which it will not do in a gun.

 

[tromic]

I don't really see any advantage even if it does work, which I doubt as he pulls at an angle on it, which it will not do in a gun.

Well, not every attempt have a satisfactory result. I do not know if there were something useful at the end..?
I suppose the goal was an softer and more safe trigger. From the first video it seems to me that the self fire is impossible. Maybe the trigger might be softer too..?

 

[popgun pete]

The mechanism would meet the short in, long out leverage principle, but once triggered the levers would need resetting. The piston tail has to sit above the front pivot axis in order to apply a rolling torque to it. The travel arcs are shown. The levers cam lock in this position. The rear element will need a long push with a vertical actuator pin, maybe more than with a see-saw trigger. Will need to roll the levers to see what release looks like.

 

[popgun pete]

It looks like the travel on the push pin is much longer than with a see-saw trigger. Ignore the thickness of the lines in this sketch, the travel arcs are about right for the sear tooth release.

One of the Trigger Mechanism Design rules is don't place the pivot pins too close together.

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Trigger Mechanism Design Rules All About Guns

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[tromic]

From the drawing you made it seems to me that it is possible to relatch with loading action pushing the piston against the upper side of the front sear lever, similar to the action of Omer Airbalete trigger...? Maybe only minor adjustment of angular movement is necessary. I think that the right part uses a spring to bring it to working position as usual.

 

[popgun pete]

You need to compare it with the standard see saw trigger, it has too much movement required of the vertical transmission pin. Once the see saw tilts the piston tail will escape the sear lever tooth, the vertical movement there is much less.

 

[tromic]

You need to compare it with the standard see saw trigger, it has too much movement required of the vertical transmission pin. Once the see saw tilts the piston tail will escape the sear lever tooth, the vertical movement there is much less.
View attachment 59228

Do yo think a long push with a vertical actuator pin is unacceptable long?

This might be the relatching sequence on loading action.

 

[popgun pete]

Do yo think a long push with a vertical actuator pin is unacceptable long?

This might be the relatching sequence on loading action.

View attachment 59229

The plastic trigger in a pneumatic gun is external and works using the leverage built into it where the transmission pin that crosses the gun's pressure boundary is driven by the short step at the upper rear of the plastic trigger. Longer strokes here require much more angular movement of the plastic trigger, probably more than can be provided. If say you need double the current linear travel on the transmission pin then the plastic trigger must swing through double the angle that it did before.

 

[tromic]

The plastic trigger in a pneumatic gun is external and works using the leverage built into it where the transmission pin that crosses the gun's pressure boundary is driven by the short step at the upper rear of the plastic trigger. Longer strokes here require much more angular movement of the plastic trigger, probably more than can be provided. If say you need double the current linear travel on the transmission pin then the plastic trigger must swing through double the angle that it did before.
View attachment 59230

Yes, that might be a problem.

 

[popgun pete]

You might obtain more swing if the trigger was like this, such "curly" triggers were used on early "outrigger trigger" guns like the second or third model Nemrod's.

Note the longer swing on the yellow grip handle gun, almost double..

 

[popgun pete]

So something like this. The pusher tab has to be redesigned as a bigger swing moves the pusher laterally which could bend the bottom of the transmission pin. In current guns it pretty much moves vertically with little sideways movement.

 

[popgun pete]

Here I have swung the trigger to demonstrate the shift on the vertical transmission pin.

 

[tromic]

What do you think Pete about this solution?

 

[popgun pete]

What do you think Pete about this solution?

View attachment 59275

Well that would straighten it up by starting lower, but if you look at the inner travel marked in blue you can see it might not be too bad. What counts is the turning or rotation axis and having not too tight an arc, i.e. the flatter it is the better.

 

[tromic]

Well that would straighten it up by starting lower, but if you look at the inner travel marked in blue you can see it might not be too bad. What counts is the turning or rotation axis and having not too tight an arc, i.e. the flatter it is the better.
View attachment 59276

What do you think Pete about this solution?

View attachment 59275

 

[tromic]

The same idea might be applied to the sear lever too, image b)

 

[popgun pete]

By gluing the two images together it looks about right, the swing diagram was just an estimate and it could have been a bit less. The transmission pin is the same length on both diagrams. A ball end on the transmission pin would work better that a flat, being the same on each end into a small cup.

Torsion springs could bias both levers, the two leg type that mount on the pivot axle. You see one on the JBL sear lever.