Patent ID: 6969311

Claim:
A pneumatic sanding machine comprising: a body comprising a motor frame having an annular portion having an exterior periphery and an inner space with a top opening and a bottom opening; an upper protrusion formed integrally on and extending from the exterior periphery of the annular portion and having a front formed integrally on the exterior periphery of the annular portion, a rear, two opposite sides, an intake air port and buffering chamber defined respectively in the rear of the upper protrusion, an intake air passage communicating with both the intake air port and the inner space of the annular portion, an exhausted air passage communicating with both the buffering chamber and the inner space of the annular portion, a valve chamber defined transversally in one of the sides of the upper protrusion to interconnect the exhausted air passage with the buffering chamber, a side bore defined in the other side of the upper protrusion and communicating with the valve chamber, and a connecting passage defined longitudinally in the valve chamber and having a bottom opening that communicates with the bottom opening of the inner space; and a lower protrusion formed integrally on the exterior periphery of the annular portion and having an air exhausting passage communicating with the inner space of the annular portion; an elbow connection fitting fitted into and held in the bottom opening of the connecting passage and having an air outlet facing the lower protrusion and aligned with the air exhausting passage of the lower protrusion; a bottom annular cover mounted to the annular portion of the motor frame; and a top cap covering the top opening of the inner space; a pneumatic motor assembly mounted and held partially in the inner space in the motor frame and comprising a sanding pad having a top and multiple powder sucking holes defined through the top and covered by the bottom annular cover; a shaft extending upwardly from the top of the sanding pad; a pneumatic motor held in the inner space of the annular portion and having a stator mounted and held in the inner space in the motor frame and having a top, a bottom, a rotor space, an air inlet aligned and communicating with the intake air passage and an air outlet communicating with the exhausted air passage; and a rotor rotatably mounted in the rotor space of the stator and connecting to the shaft for rotating the shaft; and a control valve with a first end and a second end detachably received in the valve chamber and comprising a first portion that covers and closes selectively the connecting passage and the air exhausting passage of the lower protrusion, a second portion and a neck portion interconnecting the first portion with the second portion.