When the piston is at the position shown in Figure 3, the solenoid valve has been switched to the right side. Along with the piston’s return, the air in discharging chamber is being exhausted to the receiver. When the piston reaches the position of magnetic switch “a”, the solenoid valve
switches to the left side, the air in the piston rod chamber is exhausted into the atmosphere after the manually valve switches to the other side.