Clutch device for a rollers' swinging mechanism of a belt sander

A belt sander comprising:

• a roller set located at a preset position and wrapped up with a sanding cloth and connected with a belt wheel for each roller;
• a swinging gear set having an eccentric gear set and a pulling claw fixed at an outside and pivotally connected with a fixing base at a center thereof;
• a motor set having a motor fixed with two belt wheels mounted around by a first belt and a secondary belt respectively, said first belt also mounting around said belt wheel of said roller set;
• and,
• said clutch device composed of a control bar, a linking member and a clutch member, said control bar pivotally connected at a preset position and able to turn around in a certain definite angle, an eccentric wheel fixed at a lower end of said control bar for sliding into a sliding groove of said linking member, said linking member having a bending corner fixed with a lower side of said fixing base and having a pivot riveted at an end for sliding into said clutch member, said clutch member consisting of a male clutch, a female clutch and a worm, said male clutch fitting with said pivot and having a rear side connected with said worm, said worm engaging with said swinging gear set, said female clutch having an annular groove formed in an outer portion to be mounted around by said secondary belt.