Deere + Company

Lynn E Kurt

Warren L Thompson

Andrew Paul Redman

Victor C Pierrot

Alvin Lewis Menzel

Eugene S Zirker

Leakage detection method for closed center hydraulic circuit wherein the existence of a leak within the circuit is indicated by changes in the RPM level of prime mover.

Method of checking for hydraulic leakage

A tree shear head includes a shear, a grapple tong and an accumulator tong which are positioned by respective double-acting hydraulic actuators controlled by selectively actuatable solenoid-operated valves such as to place the shear head either in a non-accumulate mode wherein both tongs operate concurrently to grasp and release trees one-by-one or an accumulate mode wherein the tongs are individually operated in a sequence resulting in the accumulation of a plurality of cut trees.

Tree shear head and controls therefor

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 to be sheared upon rotation of the crank shafts. The crank shafts are rotated by means of an actuator including a cylinder in which a pair of piston and rod units are mounted with the rods projecting oppositely and being respectively connected to the pair of crankshafts. To prevent the cylinder of the actuator from shifting axially relative to the rods and from rotating on the rods, cables are connected between the cylinder and the frame.

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Dubuque, IA, United States of America

Lynn E Kurt