Inspired Design a Winner at Grape Harvesting Season

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Harvesting grapes to make the next batch of your favorite wine requires a unique and finely-tuned piece of machinery. Mechanical grape harvesters may look cumbersome, yet they perform a delicate and time-critical task.

The fine art of grape harvesting

When harvesting season approaches, the 'over-row' harvester is run along the vine rows, where a looped harvesting rod shakes the fruit off the vine and onto a conveyor belt. When this is being done, next season’s fruit is still establishing itself on the vine and needs to be left undisturbed with the maximum of foliage intact. Ultimately, the winemaker wants to achieve the closest thing to hand-harvesting, meaning: no broken skin, no oxygen exposure, no juice left on the vines, and minimal matter other than grapes (MOG). With the added time pressure of harvesting and unforeseen weather events, this can be a stressful time of year for a grower, harvesting crew, and winery alike.

An issue that can cause potential delays is equipment breakages in the middle of the harvest. The grape harvest rods can experience breakage due to high ambient temperatures, difficult to harvest varietals, poor trellising of the vines (not machine friendly), or sub-standard materials/technical issues associated with their manufacture. Delays through repair or replacement can chew up valuable time, these are crucial hours lost which can result in loss of profits, additional unplanned R&M expense, and missed delivery deadlines.

The importance of the shaker system

The shaker rod system on a grape harvester is the heart of the machine, removing the fruit from the vine. It operates at around 400-500+ rpm in a continuous horizontal motion so is under constant flexural and fatigue strain.

These components are usually factory-made from either molded plastic, fabricated from extruded plastic, or fiberglass (or combination of both).  All these materials are prone to weakness, breakage, or splintering if manufactured from sub-standard parent material or technical issues associated with their manufacturing process.

Design change improves harvest performance

Working with customers on the ground and experiencing frustration with recurring breakages, our client, came up with a simple design to improve flexural strength and advance the overall performance of the shaker rod system. The design consisted of a high-performance composite rod with a plastic cover secured by a crimp. The composite rod plays a critical role in the design.

“The rod provides the stiffness, the whip movement, and the drive. The secret is getting the energy to flow off the fiberglass to the plastic for an even flow,” says the company spokesman.

After trialing and rigorous testing with Pultron, a final resin change was made to increase flexural and fatigue ability. A huge improvement in performance was achieved and the improved shaker component has gone on to be a commercial success for over 15 years.

With the improved shaker system and the reliability of the composite rod, the shaker rate has been slowed while running the grape harvester at the same speed. The significant reduction in shaker system speed has resulted in better fruit harvesting, reduced MOG, and less machine wear. Harvesters have noted, when using the improved shaker system, the vines are left looking untouched, work is finished at a faster rate, and there are significantly fewer breakages.