| 摘要 |
A projectile propulsive device comprises a barrel (11) having an axial bore in which the projectile (53) to be launched is located, a chamber (29) for containing air or gas under pressure and communicating with the bore of the barrel (11) through one or more lateral apertures (30) in the barrel (11) and a sleeve (25) coaxially mounted with respect to the bore of the barrel (11) and axially displaceable along the barrel (11) between a closed position in which it closes the aperture or apertures (30) to prevent air or gas under pressure in the chamber (29) from passing therethrough to the bore of the barrel (11) and an open position in which the air or gas under pressure from the chamber passes through the aperture or apertures (30) into the bore of the barrel and acts upon the base of the projectile (53) to propel it along the barrel (11) and to launch it from the end of the barrel (11). |
