Patent ID: 7325710

Claim:
A pneumatic nail gun comprising: a gun body having a unmovable cylinder therein a hitting piston disposed in the cylinder to divide the cylinder into a top chamber and a bottom chamber a main air housing collecting a compressed high pressure air with a constant pressure and a trigger at one end of the main air housing driving the high pressure air to hit a nail; at least one main passage disposed at a peripheral portion of the cylinder or a side of the main air housing, the at least one main passage being connected with the main air housing for introducing and gathering high pressure air therein, the high pressure air in the main passage being discharged after the hitting piston hitting the nail before reposting; at least one top valve hole disposed adjacent to a top portion of the cylinder; at least one top through hole disposed at a side of the main passage, and the top through hole having a cross-section smaller than that of the top valve hole and being used for continuously guiding the high pressure air from the main air housing into the main passage; and a bottom valve disposed at a bottom peripheral portion of the cylinder, the bottom valve being driven to upwardly move for continuously guiding high pressure air into the bottom chamber of the cylinder to drive the hitting piston upwardly move to reposit when the trigger is released, the high pressure air in the main passage being recharged, and the bottom valve being driven by the high pressure air gathered in the main passage to move downward to reposit after the hitting piston being reposited.