Abstract: A tree shear head includes a frame which supports a pair of parallel crank shafts which are respectively linked to a pair of shear blades for moving the latter together into the trunk of a tree being sheared. The crank shafts are rotated by means of an actuator including a cylinder in which a pair of piston and piston rod units are mounted with the rods projecting oppositely and being respectively pivotally connected to a pair of crank arms respectively formed integrally with the pair of crank shafts. To prevent the cylinder of the actuator from shifting axially along the piston rods, a pair of links are connected between the cylinder and the frame, and for preventing the cylinder from rotating about the piston rods, a pair of rollers are mounted on the cylinder and engage the frame.

Abstract: A tree shear blade is formed by pressing a pre-shaped flat metal plate or blank into a die shaped to turn up opposite side and rear tabs of the blank to form mounting portions of the blade and to cylindrically curve a central portion of the blank to form a cutting portion of the blade. The side and rear tabs are then welded together.

Abstract: An articulated, four-wheel drive tree harvesting machine includes a front frame section upon which a felling boom assembly, a delimber assembly, and a feed assembly are mounted. The felling boom assembly is operable for severing a tree and lowering it into a generally horizontal position. The tree is released into the opened knives of the delimber assembly which close to encircle the trunk and into the opened feed rolls of the feed assembly which close to engage the trunk. The feed rolls are then rotatably driven to draw the tree trunk through the knives while the felling boom may be operated to sever and position a second tree. Two solenoid-operated valves control the operation of hydraulic cylinders which respectively open and close the delimber knives and open and close the feed rolls. Two other solenoid operated valves respectively control the operation of a clutch and a transmission to drive the feed rolls in a forward or reverse direction of rotation.