Gas passage switching structure for pneumatic rotary hand tool

A gas passage switching structure for a pneumatic rotary hand tool comprising:

• a device case which forms a hollow shell-like column along an axis line and serves as a handle for the hand tool, the device case having a gas chamber capable of accumulating high pressure air, and a gas vent fluidly connected to the atmosphere being formed at least one side of walls of the device case;
• a pneumatic motor disposed along the axis line in the device case, an output ending surface and an input ending surface being respectively formed at both sides of the axis line of the pneumatic motor, the pneumatic motor having an output shaft extending over the output ending surface along the axis line, the pneumatic motor having a forward gas inlet and a reverse gas inlet which are respectively formed and spaced away on the input ending surface in the direction of the axis line;
• and
• a revolving valve which is in the form of a hollow shaft and is pivotable in the device case so that the revolving valve is located between the input ending surface of the pneumatic motor and the gas chamber of the device case along the axis line, a gas guiding passage being formed in the revolving valve along the axis line, for the revolving valve a gas supply surface and a gas inlet surface being respectively formed at both sides of the axis line, the gas supply surface being adjacent to the input ending surface, and the gas guiding passage being fluidly connected to the gas chamber via the gas inlet surface;
• wherein a gas supply port for fluidly connecting to the gas guiding passage and a discharge port for fluidly connecting to the exhaust flow division hole of the device case are formed and spaced away on the gas supply surface, an user can switch and rotate the revolving valve between an output forward position and an output reverse position, when the revolving valve is switched and rotated to the output forward position, the gas supply port is fluidly connected to the forward gas inlet and the discharge port is fluidly connected to the reverse gas inlet, when the revolving valve is switched and rotated to the output reverse position, the gas supply port is fluidly connected to the reverse gas inlet and the discharge port is fluidly connected to the forward gas inlet;
• wherein an elastic component is arranged between the revolving valve and the gas chamber.