Patent ID: 7712462

Claim:
An electrically-driven compressed air gun used for firing a projectile, said gun comprising: a power source; a motor connected to said power source; a sensor; a control circuit configured for controlling the motor using information from the sensor; a start switch configured to direct power from the power source to the motor by means of the control circuit; a barrel including a projectile inlet port to receive the projectile; a bolt operationally coupled to the barrel, the bolt configured to move between a first position and a second position and capable of chambering the projectile in the barrel when the bolt is moved from the first position to the second position and shutting off the projectile inlet port when the bolt is positioned at the first position; a cylinder comprising a front end and a rear end; a drive assembly comprising, a piston movable within the cylinder, wherein the piston defines a forward air chamber between the piston and the front end of the cylinder, the forward air chamber capable of accommodating air therein; and a rack and pinion assembly for coupling the piston to the motor for converting a rotational motion of the motor into a reciprocating motion of the piston; and a valve functionally disposed between the barrel and the cylinder, the valve configured to isolate the air in the forward air chamber from the barrel and further configured to release the air compressed in the forward air chamber through a compressed air passageway into the barrel to drive the projectile from the barrel, wherein the compressed air passageway is configured between the cylinder and the barrel by positioning the bolt at the first position; and wherein the piston moves from the rear end of the cylinder towards the front end of the cylinder and polytropically compressing the air in the forward air chamber with a compression exponent of at least 1.1.