Abstract: A belt adjusting device of the belt sander comprises a seat on which a driving roller and a driven roller are pivotally mounted. A reduction gear set is mounted on the seat and is driven by a motor. The gear set is provided with a shaft rod capable of turning in the direction perpendicular to the motor spindle and having one end which is disposed in a long slot of a swiveling member. When the shaft rod slides in the long slot, the push portion of other end of the swiveling member is caused to swivel a predetermined angle, so as to push an action rod in constant contact with the swiveling member to act. The action rod is pivoted with the driven roller. When the action rod is pushed, the free end of the driven roller is caused to engage in an up-and-down displacement perpendicular to the motor spindle. The sanding belt can be thus displaced horizontally on the two rollers to adjust automatically the contact position between the sanding belt and a workpiece.

Abstract: A belt adjusting device of the belt sander comprises a seat on which a driving roller and a driven roller are pivotally mounted. A deceleration gear set is mounted on the seat and is driven by a motor. The gear set is provided with a shaft rod capable of turning in the direction perpendicular to the motor spindle and having one end which is disposed in a long slot of a swiveling member. When the shaft rod slides in the long slot, the push portion of other end of the swiveling member is caused to swivel a predetermined angle, so as to push an action rod in constant contact with the swiveling member to act. The action rod is pivoted with the driven roller. When the action rod is pushed, the free end of the driven roller is caused to engage in an up-and-down displacement perpendicular to the motor spindle. The sanding belt can be thus displaced horizontally on the two rollers to adjust automatically the contact position between the sanding belt and a workpiece.

Abstract: A belt roller adjustment device of belt sander comprises a sanding belt attached to the driving roller and the driven roller having a main shaft fastened to support rods having inner end portions thereof being threaded and fitted over with tubular sleeves. Two cams are used to urge the inner end portions of the tubular sleeves so as to exert a force on support rods to actuate the driven roller to move outwardly in order to tighten the sanding belt with speed and precision.