Home-Built SP Tree Pruner

Home-Built SP Tree Pruner MISCELLANEOUS EQUIPMENT Miscellaneous 22-3-12 "I needed a machine that would be stable on steep sidehills in our orchards," says Kent D. McMullen who, along with mechanic Denny Huntzinger, designed and built a hydrostatic-drive, four-wheel, self-propelled tree pruner that's equipped with a telescoping boom that rotates 180 degrees, and a self-leveling basket. Commercial three-wheel models he looked at were too light to use on sidehills and had to be maneuvered into trees since the booms were only adjustable up and down, notes the Eltopia, Wash., farmer whose 830-acre operation includes 52 acres of pear, cherry and walnut trees. Before building his machine, which he calls the McSHOP (McMullen's Self-leveling Hydrostatic Orchard Pruner), McMullen pruned trees with ladders or hired professional tree trimmers. The men started from scratch, building an 11 1/2-ft. wide by 14-ft. long frame out of 1/ 4-in. thick, 4-in. sq. steel tubing. There's just 14 in. of ground clearance under the frame so it has an extremely low center of gravity. A flat plate, fitted with a plastic 5th wheel insert out of one of McMullen's semi's, mounts near the center of the frame. It serves as a base for a 1-in. thick by 32 in. dia. turret that the boom rotates on. A 7-ft. tall mast built of two pieces of 2 by 6-in. steel spaced 6 in. apart welds to the turret. The mast rotates up to 180 degrees on a greasable bushing controlled by a large sprocket above the turret that's turned by two opposing hydraulic cylinders connected to a roller chain. The 8-ft. boom telescopes out 4 ft. thanks to a 2-in. dia. hydraulic cylinder with a 4 ft. stroke. The boom is fitted with a 28 by 30-in. operator's platform with metal sides. It mounts on a yoke and bearings, which allow it to self-level back and forth and side-to-side. A control panel with a "joy stick" for steering and electric toggle switches for swing, lift and boom extension, mounts on the side of the basket. Metering valves allow the speed of movement to be permanently set, McMullen notes. A 20 hp Honda engine powers the machine and mounts on front of the machine to counterbalance the rig when the operator is in the basket. He also adds tractor suitcase weights totaling 1,400 lbs. The front of the machine is fitted with castor wheels fitted with 8-ply 9L by 15-in. implement tires while the rear has larger 11 by 24.5 drive tires off a circle irrigation system. Worm gear driveboxes and hubs off the irrigation system drive the wheels. Driveboxes can be disconnected easily for towing the rig behind a pickup and the de-sign provides it with a zero turn radius, McMullen says. For a hydraulic reservoir and fuel tank, the men used two 32-gal. tanks off a junked Deere swather mounted on back. Out-of-pocket expense was about $17,000, and McMullen says he could likely build another pruner for half that. Contact: FARM SHOW Followup, Kent D. McMullen, McMullen Farms, 4461 Ringold Rd., Eltopia, Wash. 99330.

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