Linear Actuators Handle the Load

For one newly designed bottle cleansing packaging and sorting conveyor system, improper loading of linear actuators led to excessive downtime.

The de-stacker is positioned at the forefront of the robotic packaging conveyor. Stacks of boxes on pallets containing empty bottles are stocked in the front, waiting to be moved further down the packaging line. As the de-stacker cycles down the pallet stack, it moves the 272-pound pallets into position to be lowered onto the conveyor and on to the next station.

The operation requires a system of actuators to work synchronously to complete two stacking tasks: horizontally driving the bottle boxes into lowering position and vertically raising/lowering the boxes onto the transfer conveyor. These tasks required controlled, smooth linear motion and tolerance for high offset loads. During the early stages of testing the system, the actuators experienced excessive loading beyond their ratings due to improperly aligned pallets, causing the system to fail.

The engineers of PBC Linear, a Rockford, Ill., motion systems manufacturer, were brought in to suggest a solution. When they investigated the actuator breakage, they realized extreme moment loads were the root cause. These loads occurred whenever the boxes were misaligned, exposing the actuators to more than twice their rated load capacity. Their idea was to replace the actuators with the MT series actuators. The MT series are built to handle high load tolerances.

The engineers also designed and manufactured a special hinged mount to attach the de-stacker to the actuators to prevent breakage and machine shutdown. The two mounting plates were spring-loaded—allowing the actuators to pivot when the boxes were misaligned and prevent strain from high moment loads. After the actuators were equipped with a custom mounting plate, the production line operating smoothly.

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