The conventional pneumatic tool is generally composed of a housing in which an air chamber and an air duct are located. The air duct is in communication with the air chamber in which a fan blade is located such that the fan blade is linked with a working portion. The compressed air is guided into the air chamber to drive the fan blade so as to work the working portion.
Such conventional pneumatic tool as described above is defective in design in that it makes use of a tubular body to connect the air duct and the source of the compressed air, and that a rotary joint is used to connect the tubular body and the housing. The rotary joint is often the source of trouble in view of the fact that the rotary joint can not meet the specification requirements of the pneumatic tool, and that the rotary joint is vulnerable to leak after the prolonged use of the pneumatic tool. In addition, the conventional pneumatic tool is provided with an extended air exhaust tube for reducing the noise level of the pneumatic tool. However, such extended air exhaust tube hardly works to reduce the noise level. Moreover, the air duct of the conventional pneumatic tool is provided with a flow adjusting cross rod for regulating the flow of the compressed air. In operation, the flow adjusting cross rod must be pulled along the axial direction and then rotated radially. In other words, the flow adjusting cross rod complicates the operation of the conventional pneumatic tool.