| 摘要 |
A valve body is in a cylindrical shape and communicates with the rear-side end of a barrel on the front side. The valve body forms an air chamber therein. A discharge valve is positioned in the valve body. The discharge valve is hit by a bolt from behind and thereby opens or shuts the communication between the barrel and the air chamber. When the bolt makes forward or backward slide movement, the valve body is fit into a first opening at the front part of the bolt. The cylindrical portion or the closed end of the bolt is provided with a second opening through which the air in the bolt flows in or out.
|
