Dual-effect hydraulic actuator handling system for gate moving

Abstract

A system for handling gates and the like including a dual-effect hydraulic actuator with a stem traversing one of its chambers and a supply circuit controlled with oil which alternately moves the oil between the actuator chambers for an ‘opening’ or ‘closing’ movement. The circuit includes a pump for transfer of the oil between the chambers through piloted locking one-way valves, an oil tank and two one-way suction valves each connected between the tank and one of the two sides of the pump for allowing suction from the tank of the lacking oil. The suction valve connected from the side of the pump opposite the actuator chamber not traversed by the stem is a one-way valve controlled in such a manner as to open thanks to an overpressure on the hydraulic circuit branch which is for supply of the actuator chamber traversed by the stem. In this manner the oil in excess during movement of the actuator which is caused by transfer of the oil from the stemless chamber to the chamber with stem is dumped into the tank.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

To clarify the explanation of the innovative principles of the present invention and its advantages compared with the prior art there is described below with the aid of the annexed drawings a possible embodiment thereof by way of non-limiting example applying said principles. In the drawings:

FIG. 1 shows a hydraulic diagram of the handling system in accordance with this invention, and

FIG. 2 shows a view of a piloted valve unit which realizes part of the system of FIG. 1.

Claims

1. System for handling gates and the like including a dual-effect hydraulic actuator with a stem traversing one of its chambers and a supply circuit controlled with oil which alternately moves the oil between the actuator chambers for an ‘opening’ or ‘closing’ movement with the circuit including a pump for transfer of the oil between the chamber through the piloted-lock one-way valves with an oil tank and two one-way suction valves each connected between the tank and one of the two sides of the pump to allow suction from the tank of the lacking oil and characterized in that the suction valve connected from the side of the pump opposite the actuator chamber not traversed by the stem is a controlled one-way valve with control inlet connected to be taken in opening from an overpressure on the hydraulic circuit branch which is for supply of the actuator chamber traversed by the stem meaning allowing through said one-way valve dumping into the tank the oil in excess during movement of the actuator which is caused by transfer of the oil from the stemless chamber to the chamber containing the stem.

2. System in accordance with claim 1 characterized in that said controlled suction valve has a control inlet connected between the pump and the cutoff valve connected to the chamber containing the stem.

3. System in accordance with claim 1 characterized in that between each side of the pump and the tank is connected a respective bypass valve for dumping oil into the tank which is set for an opening pressure higher than the commanded opening overpressure of the one-way valve.

4. System in accordance with claim 1 characterized in that the controlled one-way valve includes a cut-off formed by a closing ball thrust to close by a spring and a control piston moved by a fluid pressure at the control inlet to run axially against the action of an opposing spring and push the ball toward the opening position of the cut-off.

5. System in accordance with claim 1 characterized in that between the two chambers of the actuator and the tank there is a dumping tap to allow manual handling of the actuator.