Patent ID: 7475800

Claim:
A trigger valve of a pneumatic nail gun, the nail gun having an air chamber and a main air passage, the trigger valve with a valve body being disposed between the air chamber and the main air passage, which comprising: a valve bar being capable of pressed and released, one end of the valve bar forming an upper bar portion slidably attached inside the valve body, and the other end of the valve bar forming a bottom bar portion extended out of the valve body; an air exhausting passage disposed between the upper bar portion and the valve body, and connecting between the main air passage and environments; an air guiding passage connecting between the main air passage and the air chamber; and a stopper formed at an outside surface of the upper bar portion, the stopper being integrated with the upper bar portion and having a diameter larger than the bottom bar portion, the stopper dividing the valve body into an upper air chamber and a bottom air chamber; wherein the upper air chamber is connected with the air chamber via the air guiding passage, and the bottom air chamber is connected with the upper air chamber via at least one connecting passage disposed in the upper bar portion; wherein the upper air chamber generates a downwardly pushing force to drive the valve bar to downwardly move, the bottom air chamber generates a first upwardly pushing force to drive the valve bar to upwardly move and a second upwardly pushing force by pressing the valve bar, the downwardly pushing force is larger than the first upwardly pushing force for used in driving the stopper to close the air exhausting passage and open the air guiding passage; the downwardly pushing force is less than the sum of the first and second upwardly pushing force for used in driving the stopper to open the air exhausting passage and close the air guiding passage.