US Patent 7273078 Tree delimber roller system with automatic roller adjustment

A tree delimber including a base frame rotatably supporting a yoke assembly and a cutting head assembly. The yoke assembly is journalled for rotation in a ring bearing on the base frame, adjacent its front end, and supported by a pair of roller units adjacent its rear end. Each roller unit includes a vertically adjustable roller, adjustment being automatically effected by horizontal movement of a wedge driven by a control rod under the influence of fluid pressure in a hydraulic cylinder.