| 摘要 |
<p>For an automatic cannon, a pneumatic bolt and sear buffer comprises a housing fixed rearwardly of a breech ring, a cylinder, an end plate and a low mass piston projecting forwardly through the cylinder. A pin transversely installed through the piston, into slots in the cylinder and housing, limits relative axial movement between the piston, cylinder and housing. A forward cylinder flange also limits rearward cylinder movement relative to the housing. Pressurization of gas in a pressure chamber defined by the cylinder, piston and end plate is through an end plate valve. A bolt sear is pivotally mounted to a sear bracket extension of the cylinder, forwardly of the piston. After firing, recoil impact of a reciprocating bolt assembly drives the piston rearwardly into the cylinder, and upon bolt searing the cylinder is pulled forwardly relative to the piston; in both cases the buffer gas is further compressed, acting as a massless spring. A sear support or keeper is provided to prevent hitting and bouncing of the sear by the bolt assembly on searing up.</p> |
