System for operating a fluid actuator

Patent metadata

Field	Value
Publication number	US-12370730-B2
Application number	US-202118019842-A
Country	US
Kind code	B2
Filing date	Aug 1, 2021
Priority date	Aug 7, 2020
Publication date	Jul 29, 2025
Grant date	Jul 29, 2025

Abstract

A system is described comprising an actuator with a piston linearly movable and a needle shutter connected to the piston for regulating the injection flow of molten material from a nozzle into a mold. By a supply circuit pressurized fluid is brought to the piston to move it back and forth. A solenoid valve is connected to the supply circuit and configured so that in resting condition it leaves open a fluid drainage path for bringing the shutter to a closing position.

First claim

The invention claimed is:

1. System comprising:
an actuator that is provided with a piston movably mounted to be moved linearly by thrust of a fluid within two chambers separated by the piston,
a needle shutter connected to the piston for regulating an injection flow of molten material from a nozzle into a mold,
so that the shutter can move from a closing position, wherein there is no passage of molten material through the nozzle, to an opening position, wherein there is passage of molten material through the nozzle, and vice versa;

a supply circuit with a path for bringing pressurized fluid from a reservoir to the chambers with a flow direction and an opposite flow direction, the two fluid flow directions corresponding to a forward and a backward movement of the piston, respectively; and
a solenoid valve, connected to the supply circuit and configured so that in resting condition it leaves open a fluid drainage path that connects the chambers and the reservoir to allow a flow of fluid between the chambers and the reservoir determining a movement of the piston that brings the shutter to a closing position,
wherein the solenoid valve is inserted directly into the path of the supply circuit and the solenoid valve comprises two excitation positions:
a position wherein it allows fluid communication between the chambers and the reservoir by imposing in the supply circuit a fluid flow direction opposite to that obtainable in the rest position, and
a position wherein it inhibits fluid communication between the chambers and the reservoir.

2. System according to claim 1 , comprising,
a main circuit constituting the supply circuit, and
fluid by-pass ducts, arranged for by-passing the main circuit in a path and, constituting the fluid drainage path,
the solenoid valve being inserted in the path of the by-pass ducts.

3. System according to claim 2 , wherein the path of the by-pass ducts comprises one or more one-way valves.

4. System according to claim 3 , comprising a second solenoid valve which is connected to the supply circuit and comprises
two excitation positions:
a first position wherein it allows fluid communication between the chambers and the reservoir by imposing a flow direction for the fluid in the supply circuit, and
a second position wherein it allows fluid communication between the chambers and the reservoir by imposing a fluid flow direction in the supply circuit opposite to that obtainable in the first position, and
a resting position, wherein it inhibits fluid communication between the chambers and the reservoir.

5. System according to claim 2 , comprising a second solenoid valve which is connected to the supply circuit and comprises
two excitation positions:
a first position wherein it allows fluid communication between the chambers and the reservoir by imposing a flow direction for the fluid in the supply circuit, and
a second position wherein it allows fluid communication between the chambers and the reservoir by imposing a fluid flow direction in the supply circuit opposite to that obtainable in the first position, and

a resting position, wherein it inhibits fluid communication between the chambers and the reservoir.

6. System according to claim 1 , wherein the fluid is a liquid.

7. System according to claim 6 , wherein the fluid is oil.

8. Method for controlling a system according to claim 1 , wherein: controlling the system of claim 1 to raise the shutter and open a channel for molten material, the solenoid valve is energized, to lower the shutter and close the channel for molten material, the solenoid valve is de-energized, and to hold the shutter in an intermediate position, the solenoid valve ( 60 ; 70 ) is energized.

Assignees

• Inglass Spa

Inventors

• De Nadai Massimo
• Bisetto Massimo
• Rossi Massimo

Classifications

• B29C2945/76688

  nozzle · CPC title

• B29C2945/76521

  power · CPC title

• B29C45/84

  Safety devices {(B29C45/7626 takes precedence)} · CPC title

• B29C45/82

  Hydraulic {or pneumatic} circuits · CPC title

• B29C45/231

  Needle valve systems therefor · CPC title