Patent ID: 7780053

Claim:
An air injection mechanism for pneumatic nail gun comprising: a gun body having an air chamber accumulating a compressed high pressure air with a constant pressure; a valve base disposed at a side surface of the gun body and adjacent to one end of the air chamber, the valve base being integrated with the side surface or fixed to the side surface via screws, the valve base having a rod hole; a movable valve rod, one end of the valve rod engaging with the rod hole and extending out of the gun body to form a press end, and another end of the valve rod extending through the air chamber and fixing to another side surface of the gun body, the valve rod and the rod hole cooperating with each other to form an air guiding gap therebetween, the valve rod comprising a ringed pushing surface being able to reposition via being pushed by the high pressure air, the press end having a male thread thereat engaged with a screw cap that adjusts the moving distance of the valve rod; an air guiding passage formed in the valve rod, the air guiding passage comprising an air inlet port connecting to the air guiding gap and an air injection port connecting to environment; and at least one O-ring disposed at an inner surface of the rod hole that between the air guiding gap and the air inlet port for controlling the flux of the high pressure air that transmit from the air inlet port to the air injection port as well as the operation state of the air inlet port.