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Inspired Design a Winner at Grape Harvesting Season

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 U-shaped harvester is run on either side of the vines, where a looped 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 and needs to be left undisturbed with 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 waste. With the added time pressure of harvesting and unforeseen weather events, this can be a stressful time of year for a grower.

An issue that can cause potential delays is equipment breakages in the middle of the harvest. The grape harvester rods are particularly prone to breakage. Delays through repair or replacement can take 2-3 hours. These are crucial hours lost resulting in loss of profits 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 runs at around 400-500rpm in a continuous horizontal and vertical motion so it's under constant flexural and fatigue strain. These components are usually factory made from either a plastic mold or sub-standard fiberglass; both materials are prone to weakness, breakage or splintering.

Design change improves harvest performance

Working with customers on the ground and experiencing the frustration with recurring breakages, our client, Grant came up with a simple design to improve flexural strength and advance 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 Grant.

After trialing and rigorous testing with Pultron Composites, 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 this improved shaker system, and the reliability of the composite rod, Grant has been able to slow the shaker rate while running the grape harvester at the same speed. This 23% reduction in movement has resulted in better fruit harvesting, reduced waste 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 less breakages.