The performance of a trellised-fruit shaker during harvest can be substantially improved using a new gear-ratio design, according to a UC Davis agricultural engineer. Shakers commonly used to remove fruits such as grapes, apples and berries from trellis-trained vines and trees make use of an "impact rod" that moves up and down beneath the trellis wire, shaking the plant. The rod extends horizontally from one gear, which is attached via a belt to a second gear. Traditionally, the two gears have been of equal size. However, according to research by Henry Studer, a professor of agricultural engineering, harvesting efficiency can be optimized if the gear from which the rod extends is larger than its accompanying gear. "This design increases the velocity of the impact rod and the amount of displacement of the trellis wire," says Studer. He will explain the new design at 3:20 p.m. on Thursday, Dec. 19, during a talk titled "A High-Velocity, Low-Frequency Cycloidal Shaker."