US 6,293,181 B1 · Control system providing a float condition for a hydraulic cylinder

Abstract

A control system is provided with a float condition to permit a double acting hydraulic cylinder to freely extend or retract in response to external forces acting on the hydraulic cylinder. The system includes a pair of pilot operated poppet valves disposed between the opposite sides of the hydraulic cylinder and a directional control valve. The pilot condition is obtained by opening a pair of pilot operated control valves to vent the control chambers of the poppet valves to a tank through a pair of float check valves. The float check valves are operative to prevent higher pressure fluid from being transmitted from the tank to the control chambers of the poppet valves when a negative pressure occurs in the side of the hydraulic cylinder that is connected to the control chamber.

Claims9

Dependent claims

A control system for controlling a double acting hydraulic cylinder adapted to be connected to a work implement on a machine, the hydraulic cylinder having a retract side and an extend side, the system comprising:

a tank;
a poppet valve disposed between the tank and the extend side of the cylinder and having a control chamber and an orifice continuously communicating the control chamber with the extend side;
a pilot operated control valve having an operative position to exhaust fluid flow from the control chamber of the poppet valve;
a pilot valve having an operative position for moving the pilot operated control valve to the operative position;
and
a float check valve disposed downstream of the control chamber of the poppet valve to prevent flow of fluid back to the control chamber of the poppet valve.

3 more elements

Dependencies are inferred from the claim text.

Control system providing a float condition for a hydraulic cylinder

Life of this patent

Control system providing a float condition for a hydraulic cylinder

Life of this patent

Abstract

Claims9