SpudFiles

If anyone has a link to the Toolies piston valve, it would be greatly appreciated. I had it bookmarked, but got new internet software, erasing all my bookmarks.
Thanks.

What this?: http://my.freeway.net/~toolies/

Found under a min with Google.....

Michael

Hi,

Is it just me ... who sees nothing in this but a stretched coaxial?
I mean, the only reason for that long piston rod is that the barrel end is so far from the trigger piston (cup).

Eliminate the dead space and the bends in the chamber to barrel pipe, by sticking the barrel into the chamber. Shorten the rod accordingly. The design has now been improved and the coaxial reinvented?

Regards
Soren

dongfang wrote:Is it just me ... who sees nothing in this but a stretched coaxial?
I mean, the only reason for that long piston rod is that the barrel end is so far from the trigger piston (cup).

I agree, there doesn't seem to be any practical purpose for the extra complication. I used a similar idea in my original concept for a pneumati cartridge.

Hi,

So what was the improvement in the cartridge design?

Regards
Soren

In the cartridge that design would be ideal because it maximises chamber volume while eliminating dead space and offering better flow than the second version of the design I made.

When you want the best performance possible (The Toolies gun I'm making is small) for a small gun, that means as little dead space as possible and as much chamber volume as possible. Therefore, I chose a Toolies piston over "normal" coaxial diaphragm.

dongfang wrote:Hi,

Is it just me ... who sees nothing in this but a stretched coaxial?
I mean, the only reason for that long piston rod is that the barrel end is so far from the trigger piston (cup).

Eliminate the dead space and the bends in the chamber to barrel pipe, by sticking the barrel into the chamber. Shorten the rod accordingly. The design has now been improved and the coaxial reinvented?

Regards
Soren

I would expect the efficiency of a valve such as this to be higher than a coaxial because the air doesn't experience as much changing directions. I haven't actually measured it, but I wouldn't be surprised if the efficiency rivaled or exceeded tee valves. (Provided you built it inline and not over-under like toolies gun)

Also, this allows for an inline gun/valve with easily interchangeable barrels and barrels larger than a typical coaxial can support. Sure you could run a smaller tube thats not the barrel through the chamber, but that just gets you a bunch of dead space, takes away from the available chamber volume, and decreases flow.

IMO this design is very good and very underused.

clide wrote:Sure you could run a smaller tube thats not the barrel through the chamber, but that just gets you a bunch of dead space, takes away from the available chamber volume, and decreases flow.

Like Jack's latest pneumatic cart gun, I suppose?

When I first got into pneumatics, I think the first gun I read about was a huge coaxial. I thought of putting the sealing face on a rod extension like that, to get better flow, but I didn't have skill to do that.

I'm not sure why Toolie does that over-under business. I suppose you could make any other coax do that too, get something halfway between a tee piston and a coax. I like the O/U better personally b/c it makes a shorter gun, and b/c the barrel is exchangeable, and it makes loading easier.

Mine was going to be inline but I scrapped it because the piston was leaking. I might fix; all I'd have to do is cut the chamber in half.

Hi Clide,

OK it's a good point that there is no 180 degrees bend in this, and that air can flow into the barrel from all sides (opposite in a tee valve).

On the other hand, I would say that in any decently designed coaxial, the gas flow velocity in the chamber is much lower than in the barrel, and the turn-around should not matter all that much.

Regards
Soren