Firing mechanism for spring-type air rifle - has pneumatic spring formed by permanent charge of air in variable-volume chamber behind firing piston

摘要

The air rifle firing mechanism comprises a variable vol. gas chamber (52) behind a piston (28) which moves within an outer cylinder (26) in front of a rear cylinder (36). The gas chamber is defined between the piston and the rear cylinder and is sealingly closed. When the rifle is cocked, the piston is latched in its most rearward position in which the gas in the chamber is most highly compressed. The trigger releases the piston latch, causing the piston to be driven forward as the gas expands in the variable vol. chamber. This compresses the air in the outer cylinder in front of the piston until it exceeds a threshold which fires the pellet out of the breech (22). The semi-permanent charge of gas in the chamber thus constitutes a pneumatic spring.