US Patent 7654886 Pneumatic grinder

The present invention is a pneumatic grinder, with a housing, an air chamber stand, and a rotor. The air chamber stand includes a cylinder, an upper cover and a lower cover. The cylinder is fitted with an inlet hole and an exhaust hole. There is a lateral exhaust hole assembled on the upper cover or lower cover or both covers and provided with a vertical internal borehole section linking the air chamber within the air chamber stand, and a transverse external borehole section. The air exhaust capacity of the air chamber stand is increased, markedly reducing turbulence and improving rotational speed and strength of the rotor. The vibration of rotor is efficiently reduced for the users, thereby improving significantly the torque, performance and quality of the pneumatic grinder with better applicability.