The main difference between the Shocker Sport and the rest of the world's electropneumatic paintball markers is that it uses two solenoids to regulate the firing cycle. Because of this, Shockers are able to use two independent systems to move the bolt and to actually fire the marker. In fact, it is the only marker to do this besides for the AKA Excalibur. It will probably always be this way since, in many cases, a single solenoid can be carefully configured to perform similar operation (at least, with the proper development).
Shocker Design and Layout:
As said in the introduction, there is no hammer which strikes a valve to open it. There is instead a set of pneumatic poppets/pistons which control the firing. This firing assembly is located in the large body bore which runs the entire length of the body. At the rear of the body is the fill poppet; at the front is the fire piston, and the air chamber to fire the ball is located in between. The fill poppet and fire piston have a thin, steel rod connecting them in the middle of the dump chamber (this is known as the fill poppet rod). This rod is used during the firing cycle to open and close the air chamber's inlet.
Located on the other side of the body is another bore that houses the four AA batteries which are used to power the electronics. The batteries have a life of approximately 75,000 to 100,000 shots; however, we recommend changing the batteries on a monthy basis if the marker is used often. Located between the battery and firing assembly bores is another chamber, which is essentially empty. This is the Shocker's air distribution manifold, which supplies all the parts of the marker with pressurized air from the regulator. A similar manifold chamber is found on the later Shocker Sport, Impulse, and similar varieties can be found on many other markers as well (however it is usually shorter and doesn't run the length of the body, for size reasons). This manifold feeds the solenoids and firing assembly with pressurized air. The regulator attaches via gasline to the rear of the body through a 1/8" NPT port.
The top section of the receiver holds the bolt's bore. The bolt itself is a unique device that is comprised of another pneumatic piston which connects to the actual bolt tip itself. By unscrewing the knob at the back of the body you can remove the bolt piston with bolt tip attached, but don't do this while the Shocker is pressurized or air will leak out. The bolt tip moves back and forth in accordance with the pressurization of the different sides of the piston. Do not be fooled by the fact that the Shocker is field-strippable. This does not mean that the bolt should be taken out of the marker at any time during play. As said, air will continuously leak out and you will have to remove your tank in order to get the bolt's o-rings to seal again.
pVI Shocker body diagram (scan from the manual)
Firing assembly diagram. This is actually a diagram of a Shocker Sport marker however the parts are essentially the same (just rearranged).
Attached to the underside of the receiver, contained within the top section of the marker's frame, are the two solenoids. These solenoids aren't used in any other marker and furtuermore no other marker uses any solenoid from the same manufacturer. These are direct-acting solenoids which means their air valves are linked directly to the electromagnet inside them, which is different from some other solenodis out there (that use tiny air valves to operate the main solenoid valve). The type of solenoid used here is a three-way, normally-closed. These solenoids regulate the movements of the valve piston and the bolt piston respectively. They are connected to the main control board which is located in the frame. The soleniods operate on approximately 5-6 volts. pneuVentures Shockers also have two seperate off/armed switches to disable the board from the batteries. The only other feature located on the top of the frame is the jack for the optional remote triggering device. This will essentially allow you to fire the marker without pulling the trigger, instead you hold a switch in your hand which you activate to fire the marker.
Lastly, there is the grip frame. It houses the Shocker's control circuitry within the grip. This is a small, colorful, parallelogram-shaped circuit board. The frame also contains the trigger assembly. The Shocker features a .45 grip frame and a standard bottomline adapter screw pattern.
Firing Cycle Synopysis:
While the Shocker rests idle, its bolt is closed and its air chamber is filled with pressurized air. The pressure in the air chamber will be used to propel the next round when it is fired, however it is held in by a seal created at the rear of the fire piston. This is caused by the pressure that enters the valve piston from the manifold and pushes against the front of the fire piston within, which pushes it back against the small port leading into the air chamber. The fill poppet rod fits inside the back of the fire piston, and since the fire piston is in the rear position, it pushes the fill poppet open at the rear of the receiver (against the fill poppet spring). So while the valve remains closed (in the rear position), the fill poppet will be open. When the poppet is open it will allow air from the main distribution manifold into the air chamber. The pressure from the manifold is greater than that of the poppet spring, so it and everything involved remains in the back position. Now we begin the firing cycle.
When you pull the trigger, the three-way solenoid pushes pressure up into the back of the valve piston, which pushes against the gradient of pressure from the manifold in the front of the fire piston. While the three-way solenoid remains open, the valve will remain forward. Just as it moves forward, the spring in the fill poppet pushes the poppet forward as well, which closes the connection between the air chamber from the manifold so no pressure can enter during firing (it's not a perfect seal but it is good enough to keep inconsistencies down). Once the fire piston moes forward, the seal between it and the air chamber is broken, which allows the pressure in the air chamber to diffuse into the front of valve fire piston and up into the bolt tip, where it is directed down the barrel. As said, the seal created within the fill poppet isn't perfect, as it does allow a small amount of air to leak through during the fraction of a second while it is closed, however there is not enough deviation to cause inconsistencies in velocity (as in, the same amount of air leaks through each time it fires). Then after a few milliseconds the three-way solenoid closes again, which allows the gradiant of pressure in the front of the valve piston to push the fire piston back, again sealing off the valve from the air chamber and again allowing the air chamber to be refilled through the opening of the poppet behind it. The marker is now ready to fire again.
The other event that happens independently of the actual firing is the movement of the bolt. The bolt is given just enough time for the air chamber to empty through it, then after a metered amount of time, the four-way solenoid moves the bolt tip back to open the breech and load another paintball. After another metered amount of time the bolt closes again by switching the solenoid back. The four-way solenoid uses more air than the three-way because air pressure is constantly flowing through it unlike in the three-way where air pressure only travels through it when firing. However, it is irrevelant because the amount of air that is fired through the valve is much more then that used to cycle the bolt (in fact it's almost four times more).
below is an animation of the firing assembly on the then-future Shocker Sport, which has a few parts redesigned or reintegrated into the body. The principals are the same, however.
