Patent ID: 6065172
Filing Date: 2000-05-23
Classification: B65G

Abstract:
A hydraulic control circuit for a dock leveler which includes a deck pivotable between stored and raised positions and a lip pivoted to the deck for movement between pendant and extended positions, the hydraulic control circuit comprising:a deck cylinder couplable to the deck for controlling motion of the deck;a lip cylinder couplable to the lip for controlling motion of the lip;a reservoir for a supply of hydraulic fluid,a pump for providing a source of pressurized fluid to the deck and lip cylinders, and in fluid communication with the reservoir;an operator-actuated switch; anda fluid valve in communication with the pump and the reservoir, the valve having a first position wherein the valve directs the pressurized hydraulic fluid to the deck cylinder and provides a path for the lip cylinder to drain to the reservoir, and a second position wherein the valve directs the pressurized hydraulic fluid to the lip cylinder, wherein actuation of the operator-actuated switch causes the valve to assume one of the first and second position regardless of the hydraulic pressure in the circuit and regardless of the position of the deck.