Fingerhut Corporation

Roy Frank Brandt

Donald W Olson

A vacuum apparatus and method are provided for controlling operation of a vacuum force to be applied through a vacuum cup for use in lifting objects such as cardboard boxes, so as to unload a pallet holding one or more of the boxes. The apparatus includes a valve body defining an inner chamber, a lift vacuum passage extending through the valve body to the chamber, a pilot vacuum passage extending through the valve body to the chamber, and a vacuum cup passage extending through the valve body to the chamber. A vacuum cup is connected to the valve body in airflow communication with the vacuum cup passage. A piston is disposed in the chamber and positioned for reciprocal movement between a first position and a second position. In the first position, the piston provides an airflow passageway between the pilot vacuum passage and the vacuum cup passage such that, if the vacuum cup is obstructed, the piston is pulled down by the pilot vacuum force to a second position. In the second position, the piston provides an airflow passageway between the lift vacuum passage and the vacuum cup passage in order to apply a lift vacuum force to an object obstructing the corresponding vacuum cup.

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St. Cloud, MN, United States of America

Roy Frank Brandt