Belt grinder

A belt grinder, comprising:

• a frame;
• and
• a first grinding assembly, comprising:
• a transmission roller set, comprising a driving roller and at least one driven roller, and both the driving roller and the at least one driven roller being rotatably disposed on the frame;
• a grinding belt, being installed over the driving roller and the at least one driven roller;
• and
• an adjusting assembly, comprising:
• a rotatable component, being rotatably and movably disposed on the frame, a rotation axis of the rotatable component being parallel to a rotation axis of the driving roller wherein a movement direction of the rotatable component is perpendicular to the rotation axis of the driving roller, and the rotatable component is movable toward or away from the grinding belt in the movement direction perpendicular to the rotation axis of the driving roller;
• and
• a plurality of contact rollers, being rotatably disposed on the rotatable component, and at least two of the plurality of contact rollers being different in shape;
• wherein the rotatable component is rotatable with respect to the frame so as to force at least one of the plurality of contact rollers to contact or to be separated from the grinding belt, one of the plurality of contact rollers has a groove, and another of the plurality of contact rollers has a width smaller than a width of the grinding belt.