Abstract: A swing device for a grinding machine includes a motor located on a fixed table beside the sanding unit which includes a frame with two mandrels and a sanding belt is mounted to the two mandrels. A movable member is movably mounted to the shaft of the motor so as to move back and forth to activate two limit switches which are activated to stop the motor. The movable member is connected to a fixed plate connected to an end plate on the sanding unit and a link is connected between the fixed plate and an elongate slot of the movable member. The sanding unit together with the sanding belt swing when the movable member moves. The sanding belt swings and activates two micro switches to change the rotation direction of the shaft. The sanding belt swings to change the sanding portion contacting the objects to be polished.

Abstract: A swing device for a grinding machine includes a motor located on a fixed table beside the sanding unit which includes a frame with two mandrels and a sanding belt is mounted to the two mandrels. A movable member is movably mounted to the shaft of the motor so as to move back and forth to activate two limit switches which are activated to stop the motor. The movable member is connected to a fixed plate connected to an end plate on the sanding unit and a link is connected between the fixed plate and an elongate slot of the movable member. The sanding unit together with the sanding belt swing when the movable member moves. The sanding belt swings and activates two micro switches to change the rotation direction of the shaft. The sanding belt swings to change the sanding portion contacting the objects to be polished.