Patent Number: 6,293,181

Title: Control system providing a float condition for a hydraulic cylinder

Abstract: A control system is provided with a float condition to permit a doubleacting hydraulic cylinder to freely extend or retract in response toexternal forces acting on the hydraulic cylinder. The system includes apair of pilot operated poppet valves disposed between the opposite sidesof the hydraulic cylinder and a directional control valve. The pilotcondition is obtained by opening a pair of pilot operated control valvesto vent the control chambers of the poppet valves to a tank through a pairof float check valves. The float check valves are operative to preventhigher pressure fluid from being transmitted from the tank to the controlchambers of the poppet valves when a negative pressure occurs in the sideof the hydraulic cylinder that is connected to the control chamber.

Inventors: Hajek, Jr.; Thomas J. (Lockport, IL), Tolappa; Srikrishnan T. (Aurora, IL), Mather; Daniel T. (Lockport, IL)


International Classification:

Expiration Date: 09/25/2013