Controlled flow hydraulic system

• US 4,625,513 A
• Filed: 03/28/1983
• Issued: 12/02/1986
• Est. Priority Date: 03/28/1983
• Status: Expired due to Term

• Current Assignee: Putnam L. Crafts Jr, Royco Company, LLC, Tinicum Investors
• Original Assignee: Rexa Corporation
• Inventors: Glomeau, J. Robert
• Primary Examiner(s): Garrett, Robert E.
• Assistant Examiner(s): Husar, John M.
• Application Number:
  US06/479,673
• Time in Patent Office: 1,345 Days
• Field of Search: 60/390, 60/431, 60/430, 60/436, 60/415, 91/451, 91/452, 91/454, 91/390, 91/468
• US Class Current: 60/431
• CPC Class Codes: F15B 13/01 Locking-valves or other detent i.e. load-holding devices

Abstract

In the hydraulic system disclosed herein, a flow matching device is employed to implement a system in which filling, emptying and holding of a variable volume load, such as a hydraulic piston, may be accomplished at controlled flow rate by a hydraulic circuit including a flow matching control valve.

Claims

1. A hydraulic system comprising:

a fluid reservoir;

a bidirectional pump;

a variable volume load having an inlet port, said load being moved in one direction by the introduction of fluid through said inlet port and being moved in the opposite direction by the withdrawal of fluid from said inlet port;

a flow matching control valve having a source port, a load port and a drain port, said control valve being characterized in that a hydraulic flow into the source port produces a matching controlled flow into the load port, both flows exiting the control valve together through said drain port;

means connecting said reservoir to both sides of said pump through respective check valves permitting flow from the reservoir toward the pump;

means connecting one side of said pump to the source port of said control valve;

means connecting the load port of said control valve to the inlet port of said load;

means connecting the drain port of said control valve to said reservoir; and

means connecting the other side of said pump to the inlet port of said load through a check valve permitting flow from said pump toward said load.

2. A hydraulic system comprising:

a fluid reservoir;

a bidirectional pump;

a variable volume load;

a flow matching control valve having;

a generally tubular body;

a source port at a first axial position along said body;

a load port at a second position along said body which is axially spaced from said first position;

a drain port between said source and load ports;

in said body, an axially floating plug member which is movable axially within said tubular body responsive to any difference in the pressures at said source and load ports, said body including rigidly connected first and second surfaces which are axially spaced, said plug member including a pair of rigidly connected third and fourth surfaces which are axially spaced, said first and second surfaces simultaneously mating with said third and fourth surfaces such that axial movement of said plug member will progressively open said source and load ports in synchronism, said body and plug member providing, between them a chamber which is located axially between said source and load ports and with which said source and load ports communicate when open;

a drain port opening directly into said chamber axially between said first and second surfaces;

means connecting said reservoir to both sides of said pump through respective check valves permitting flow from the reservoir toward the pump;

means connecting one side of said pump to the source port of said control valve;

means connecting the load port of said control valve to said load;

means connecting the drain port of said control valve to said reservoir; and

means connecting the other side of said pump to said load through a check valve permitting flow from said pump toward said load.

3. A hydraulic system comprising:

a fluid reservoir;

a bidirectional pump;

a variable volume load having an inlet port, said load being moved in one direction by the introduction of fluid through said inlet port and being moved in the opposite direction by the withdrawal of fluid from said inlet port;

a flow matching control valve having;

a cylindrical body providing first and second, axially displaced, valve seats both of which face in the same direction;

in said body, a plug member which is movable axially in response to a pressure differential and which includes valving surfaces which are axially spaced so as to mate simultaneously with said seats and to open synchronously, one of said mating pairs forming a source port and the other forming a load port;

said body and plug member providing, between them, a chamber which is located axially between said valve seats;

a drain port opening into said chamber;

means connecting said reservoir to both sides of said pump through respective check valves permitting flow from the reservoir toward the pump;

means connecting one side of said pump to the source port of said control valve;

means connecting the load port of said control valve to the inlet port of said load;

means connecting the drain port of said control valve to said reservoir; and

means connecting the other side of said pump to the inlet port of said load through a check valve permitting flow from said pump toward said load.

4. A hydraulic system comprising:

a fluid reservoir;

a bidirectional pump;

a variable volume load having an inlet port, said load being moved in one direction by the introduction of fluid through said inlet port and being moved in the opposite direction by the withdrawal of fluid from said inlet port;

a flow matching control valve having;

a generally tubular sleeve;

a piston axially slidable within said sleeve, said sleeve and piston having a first pair of mating valving surfaces and, axially displaced from said first pair, a second pair of mating valving surfaces, said valving surfaces being matched to open in synchronism;

in said piston, a first passageway from said first valving surface to one end of said piston to connect with a source port and a second passageway opening from said second valving surfaces to the other end of said piston to connect with a load port;

in said sleeve, passageways connecting both sets of said valving surfaces to a drain port

at one end of said sleeve, a valve seat;

a valving member adapted to mate with and close off said seat, said piston including a portion which, during movement of the piston, engages said valving member to lift it off said seat substantially at the same time that said mating valving surfaces open;

means connecting said reservoir to both sides of said pump through respective check valves permitting flow from the reservoir toward the pump;

means connecting one side of said pump to the source port of said control valve;

means connecting the load port of said control valve to the inlet port of said load;

means connecting the drain port of said control valve to said reservoir; and

means connecting the other side of said pump to the inlet port of said load through a check valve permitting flow from said pump toward said load.