Over the top

Brandon Mulvaney (in the blue shirt) operates the over-the-row platform wirelessly.

It began two years ago with a rough sketch on a napkin, followed by a design on legal paper, and then a mockup made of PVC (polyvinyl chloride) pipe driven by a tractor.

This summer, the final proof of concept was unveiled: a 54-foot wide, 17,000-pound, 80-horsepower over-the-row self-propelled platform designed to carry up to 20 workers down five orchard rows simultaneously.

"It’s more sophisticated than maybe we had anticipated," commented Karen Lewis, Washington State University Extension educator for the Columbia Basin, principal investigator for the project, as she admired the machine.

Looking for ways to improve labor efficiency, a group of growers approached the Washington Tree Fruit Research Commission two years ago with the idea of developing a platform that could cover multiple rows. The commission contracted with Vine Tech Equipment of Prosser, Washington, to build such a machine with input from growers on the development committee. Vine Tech has experience building over-the-row sprayers and pruners for vineyards.

The machine is being tested in several orchards this summer. Lewis stressed that it is a proof of concept, not a prototype. She planned to run it as often and for as long as possible in commercial settings to test the robustness of the mechanics and engineering. She is also comparing the efficiency and dynamics of having orchard employees on a multirow platform versus a single-row platform or ladders. The machine has two seven-foot-long platforms, large enough to carry two people, in each of the five rows. Each platform can be moved up or down and closer to or further from the tree by the people standing on it, independently of the other platforms.

Jack Maljaars, owner of Vine Tech, said there’s concern that fruit growers won’t adopt single-row platforms because of the high cost of fuel. "When you’re talking about moving people through the orchard, we hope to see some efficiencies of one single engine moving this many people."

The machine’s top speed is eight feet per minute, or three miles per hour. It consumes about 1.5 to 2 gallons of fuel per hourabout the same as a tractor.

Evolving design

The design evolved dramatically during the two years that the machine was being constructed. Initially, the idea was to hang the platforms off a central tractor.

"As we engineered it and drew it up, and kept working on it, it became too much of an overhanging load to do it that way," Maljaars explained.

The proof of concept has wheels in the second and fourth rows, which provides it more stability. It also includes features and technology that weren’t planned initially, including wireless controls. It can be controlled by an operator standing up to 500 feet away.

Brandon Mulvaney, a research technician assistant with the Washington Tree Fruit Research Commission and video-game enthusiast, operated the machine when it was tested at C & M Orchards, near Prosser, Washington. Mulvaney said it requires good hand-to-eye coordination. Controlling the wheels proved tricky at first, but it was fun when he got used to it. "It’s the biggest piece of machinery I’ve ever driven," he commented.

The wheels swivel so that when the machine reaches the end of the rows, it can be driven sideways (crablike) along the edge of the block to the next rows that need to be worked on, so it doesn’t need to be turned around.

When moved from orchard to orchard, the 16-foot, 6-inch-tall machine is usually transported on a Lowboy trailer. However, when moved two miles between orchards at Prosser, it was driven sideways down the road. With a depth of 21 feet, it took up the entire road.

C & M Ochards, owned by Craig and Mike O’Brien, proved a perfect match for the machine. In a mature Gala block where it was tested, the trees are spaced two feet apart to form fruiting walls, with ten feet between rows.

"This is ideal," Maljaars said. "Not only because of the way it’s designed, but the growers who own this did a very good job of canopy management. It’s a picture-perfect orchard."

Although trellised systems are ideal, it can be used in orchards with freestanding trees. The machine can be adjusted to cover alley widths of 8 to 24 feet. At the 24-foot spacing, it would cover only two rows. The platforms can move six feet up and down and two feet in and out to enable workers to reach the trees or negotiate branches.

Maljaars said he sees potential for a smaller machine that would be the same height and depth but would be narrower and lighter and cover only three rows instead of five. "The whole idea behind this project was proof of concept, and one of the biggest concepts we need to prove is that we can put people on herelet’s say two per platformand they can work in unity and be efficient," he said. "Let’s say we get 20 people on, and five are slow, and it’s holding the whole machine back. We need to see whether that happens, or it’s not an issue. When you have one person with one ladder, you can control that individual person, but when you’re doing this, you’re managing a whole crew of people who need to work at the same speed."

The machine as it stands now could be used for training, thinning, and pruning. The 24-inch-wide tires are designed for flotation in muddy conditions during the pruning season. For harvesting, a bin-filling system that would elevate the fruit over the rows would need to be added. There’s the potential to hang spray equipment from the machine in place of the platforms, but the machine would need to be decontaminated before people could work on it.

Craig O’Brien said he is always interested in new technology, particularly if it can reduce labor needs or enhance fruit quality. His orchard’s recent plantings have rows nine feet apart, which O’Brien said was the tightest spacing possible when an apple bin has to be placed in the row during harvest. "If we did away with the apple bin or put it above the orchard, we could go to six-foot rows and shorter trees," he said.

The over-the-row platform would be attractive economically if it could be used to spray five or six rows at a time, and could pay for itself in that area alone, he said. However, the challenge of decontamination might prevent it from being used both as a sprayer and a labor-assist machine.

Proof of concept

Dr. Jim McFerson, manager of the Washington Tree Fruit Research Commission, said the commission provided funding of $108,000 for the construction of the machine, and Vine Tech paid for outside engineering work.

"This is a proof of concept; this is not a commercial machine," McFerson said. "If we’re able to run it, and it works fairly well, and it doesn’t break, I think we’ve accomplished a great deal. I feel it works into the Technology Road Map and takes us further down the road. Hopefully, it opens people’s eyes to the possibilities. The point is to provide opportunities to move ahead."

Coleman Roland, Vine Tech’s shop foreman, dedicated 18 months of his working life to building the massive machine, despite skepticism even among his colleagues that it would work. But Roland never had doubts. "You’ve got to believe it’s going to work. I put a lot of myself into it," he said. "You’ve got to find faster and better ways to do the job."