The loading of heavy pails and cases by hand onto pallets was taking its toll on workers at JTM Products Inc., Solon, Ohio, but the remedy was automation rather than aspirin.
The company runs two production lines. On one, tire-mounting lubricant is packaged in pails. The other loads pipe joint lubricant in cardboard cases of quart or gallon containers. FKI Logistex, St. Louis, a provider of conveyor systems, carousels, and high-speed sorting and palletizing equipment, proposed a system that could handle both lines and ease employees' aching backs.
A Motoman UP165 palletizing robot first locates a stack of pallets by means of a sonic sensor. Its articulated arm uses grippers attached to two rotary actuators to pick up the wooden pallets and place them at the beginning of a conveyor.
The robotic arm then picks up one to three 25 or 40-lb pails at a time by attaching to their tops, loading them neatly on the pallet. The tool has 23 bellows-style cups, each with its own venturi-style vacuum pump. The vacuum flow rate adjusts to overcome the porosity of the cardboard cases. And the palletizing cell lets JTM run both production lines simultaneously.
The vacuum tool has an off-the-shelf collision sensor. The lower portion of the sensor (mounted to the tool) moves with respect to the upper portion (mounted to the robot). Internal springs and an internal pressure chamber hold the sensor rigid. The springs let the lower half of the collision sensor default to a neutral position. When the tool is loaded and traveling at high speed, additional air pressure through one port makes the sensor more rigid. When the tool is empty, increasing air pressure through another port makes it more sensitive. A floating option lets the lower half of the tool move up when picking up or placing outoftolerance product.
In a typical day, the palletizing cell handles either 60 pallets of 25-lb pails, 20 pallets of 40-lb pails, 40 pallets of quart cases, or 25 pallets of gallon cases.