Improvements in tree stump grinders and methods of grinding tree stumps

摘要

The tree stump grinder is adapted to be attached to a backhoe or an excavator with a boom and a stick. The tree stump grinder includes a yoke which is pivotally secured to the stick. A hydraulic grinder swing cylinder is provided to pivot the yoke relative to the stick. Fixed stub shafts are secured to arms of the yoke. Circular end plates are attached to the respective hubs. One hub is rotatably journaled on one stub shaft and the other hub is rotatably journaled on the other stub shaft. A hydraulic motor is fixed to one stub shaft and drives the other hub. A grinder drum is attached to the circular end plates and encloses the hydraulic motor. Oil is supplied to the hydraulic motor through passages in one of the stub shafts. A plurality of block and bit assemblies are attached to the outside surface of the grinder drum. An anchor assembly is also pivotally attached to the stick. A hydraulic anchor cylinder is connected to the stick and the anchor assembly for pivoting the anchor assembly relative to the stick. Hydraulic fluid is supplied to rotate the grinder drum and to position the anchor assembly and the yoke.