Patent attributes
A hollow cylindrical pulley body 5 is carried rotatably by a hollow cylindrical shaft member 11. A support rod 8 is inserted in the shaft member 11 to support the shaft member 11 for rocking motion about a pivot axis C2 orthogonal to the shaft member 11. The pivot axis C2 is inclined backward in the direction of belt travel with respect to the direction of load on the shaft member 11. With this configuration, when the drive belt 3 deviates to one side, the pulley body 5 is immediately angularly moved so that it is inclined with a level difference with respect to the direction of load on the shaft member 11 and is positioned obliquely relative to the drive belt 3, thereby producing a force of returning the drive belt 3 to its normal position.
