Alpha C speargun

I've looked at the picture in patent. Now I understand the idea. It is similar to idea of two part piston, but in this case, after shooting, one piston moves back opening the air flow hole in front of it, while the front piston under air pressure pushes the shaft forward.

This is the Inalex speargun which has been discussed here on another thread. The moving butt resets the mechanism from memory.

Found it: http://forums.deeperblue.com/pneumatic-spearguns/88246-inalex-alpha-c1-pneumatic-speargun.html

I checked a number of the web references made in that "Inalex Alpha C1 speargun" thread and they no longer show any photos, some appear to have been removed by the forum administrator for that web-site. I found another Greek forum (GreekDivers.com) discussing the "Alpha C1" guns, but there was no substantive info beyond the usual speculation and a few comments about elements which we already know about (the thread starts in 2007 and last entry is in June 2012). So the "Alpha C1" gun has been around for a number of years now and one of its main problems may be that it is too heavy for what it does. Today pneumatic spearguns are all what used to be called "super light" models, in fact that is what the "SL" in the Cressi-Sub rear handle speargun name stands for. The "Sten", "Cyrano", "Asso" and other "super light" guns are all floating after spear discharge spearguns. It is very hard for non-floating guns to penetrate the market now unless the style of hunting is not greatly inconvenienced by using a sinking gun (such as on scuba). I have used non-floating pneumatic and hydropneumatic spearguns, but my preference is to use a floating gun as to some extent it can look after itself when I throw it to one side as I grab the victim. Guns heading for the bottom can run into rocks, so your attention is divided unless you can hook the gun to a float, your belt or "park" it in a safe location on the bottom (large sheets of broken off kelp are very handy as long as there is no surge). My "Aquatech" guns sink, so I am less likely to use them for that reason once the novelty wears off in using them, plus a trip to the bottom risks sand going where I would rather it did not. The "Alpha C1" will have the same distractions for the user unless it floats.

All the releasing valve guns hold their spears in with a vacuum and if they have a piston then the piston is held with the vacuum and the piston then holds the spear. The GSD guns work this way, except for the "Punto" which was their final gun as the piston on that gun has a ring grooved tail which is held by three balls disposed in a ring arrangement. The other GSD models just have a seal on the bare piston tail, although I am not sure about the last model of the previous shape which was called the "Pull" as I have never had one of those guns to pull apart. They were said to have a new trigger mechanism which was simplified compared to the "Dynamic" and "Katiuscia" models which were both releasing valve guns.

It is possible that the "Alpha C1" has three balls holding the releasing valve and that item 19 is one of three. I have manipulated the drawing to show the valve released, but I don't see a ball control system to push the balls back, so this may not be correct. The arrow shows the reset action of the rear cap that pushes the releasing valve back for the next shot. This is just my best guess as the original drawing is very simplified, for example the spear is shown as a thin black line and so is the trigger activated push rod. Item 32 appears to be a valve seat. There must be another valve inside the releasing valve to enable it to allow air through its nose section when the gun barrel is used as an air pump before the gun is reconfigured for shooting as well as for muzzle loading the gun. Sometimes a short rubber tube is used as a valve, like the one on the "Mirage" pumping barrel, it expands off its cylindrical seat to allow air through, then collapses back to seal. The bulkhead and parts of the releasing valve system will add to the weight of the gun with the flooding rear cap (item 29), so for the gun to float some weight reduction is needed here. The "Mirage" floats because despite two inner barrels nearly everything else is made of plastic in the body of the gun, except of course the outer tank and the muzzle. Molded plastic bulkhead sections made the super light (superleggero) guns possible, but plastic moulding dies are expensive to manufacture unless their cost can be spread over large production volumes for the guns. That is why totally new guns from the major manufacturers are often decades apart in terms of them being released. Smaller manufacturers often machine bulkheads out of metal, so their guns are usually going to be heavy.

An improved diagram showing the slide (21) in the "fired" position and downwards displaced ball sear (19) highlighted in black.