This invention relates to a new type of drive unit having a base and riding wheels, a conveyer belt winding on the two riding wheels and supporting rotating of roll on the working machine, forming a basic riding wheel set in which the riding wheels are mounted on a device with adjustable central distance and a slot preventing off tracking of the belt, a spacing rollar preventing the roll moving axially at the place corresponding to internal side edges of the two wheels on the roll. This invention is used to reform roll equipments like grinders, rotary kilns, and agitators to eliminate big gear collars and hollow bearing or support. |