Patent attributes
A boom unit for a tree processing machine having a boom with a square cross-section. The boom unit has a boom support with a front boom mounting at the front end of the support and a rear boom mounting at the rear end of the support. The boom is movably mounted through the front and rear boom mountings and is positioned to have a corner of the boom on the bottom and an opposite corner of the boom on the top directly over the bottom corner. The front mounting has a pair of front, bottom rollers arranged in a v shape to cradle the boom with the bottom corner of the boom between the rollers and a single, top, guide member above the bottom rollers and centered with respect to the bottom rollers to ride on the top corner of the boom to hold the boom against the bottom rollers.