Patent ID: 8074736

Claim:
An pneumatic tool with an improved sound proof device, comprising: a housing, which is hollow has an axial screw hole for supplying a high-pressure gas on the rear end thereof; an pneumatic motor, which is disposed in the housing with an pneumatic switch provided on one side thereof; wherein the high-pressure gas entered via the screw hole is controlled by the pneumatic switch to drive the pneumatic motor, and the exhaust gas after driving the pneumatic motor leaves the housing from its rear end; a supporting base, which has an annular base that has a stop wall therein; wherein the supporting base urges against the rear end of the housing by the stop wall, the center of the stop wall has an axial through hole, and a plurality of axial connecting holes are formed around the penetrating hole; a cover, which covers and fixes on the supporting base and whose center is formed with an axial penetrating hole; a guiding element, which has an annular shape and has a small-diameter end and a large-diameter end, with a guiding section gradually expanding from the small-diameter end to the large-diameter end; a gas exit passageway being in contact with and defined in part by the guiding element, the small-diameter end is further extended with a small-diameter section that goes into the penetrating hole of the cover, and an annular ventilation space is formed between the guiding section of the guiding element and the penetrating hole; and a gas inlet connector, which has a head part, a body part, and a shoulder part between the head part and the body part; wherein the body part of the gas inlet connector penetrates in sequence through the guiding element, the penetrating hole, and the through hole and into the screw hole; the small-diameter section of the guiding element mounts on the body part of the gas inlet connector connected in the screw hole, and the shoulder part of the gas inlet connector stops the guiding section of the guiding element, whereby gas is supplied to the pneumatic motor through the gas inlet connector and is vented from the pneumatic tool through the gas exit passageway and the annular ventilation space, the guiding section of the guiding element changing a direction of gas flow, wherein a longitudinal axis passes through the gas inlet connector and the guiding section of the guiding element vents gas in a direction non-parallel to the longitudinal axis, and wherein a plurality of conic urging parts are provided on an interior of the cover, the interior of the cover being a flow-guiding surface which is a part of the gas exit passageway and the conic urging parts directing the flow of gas.