Patent ID: 7213500

Claim:
A pneumatic tool comprising: a shell defininig a first space, a second space communicated with the first space, a third space communicated with the second space, a fourth space communicated with the second space, a channel communicated with the second space, an inlet communicated with the channel, and an outlet communicated with the second space; a cylinder put in the first space, the cylinder defining first, second and third ports, wherein pressurized air drives a rotor in the cylinder in a direction while entering the cylinder through the first port and leavinig the cylinder through the third port, wherein pressurized air drives the rotor in an opposite direction while entering the cylinder through the second port and leaving the cylinder through the third port; a cover connected to the shell, the cover defining an aperture communicated with the second space, a first channel communicated with the third space on one hand and the first port on the other hand, a second channel communicated with the fourth space on one hand and the second port on the other hand, and a rotational switch extendirnr into the second space through the aperture and comprising two cutouts, wherein different portions of the channel open to selective one of the cutouts as the rotational switch is rotated in the second space so that the rotor is driven at different speeds, wherein the channel comprises a cruciform profile.