Self-contained actuator

• US 6,282,893 B1
• Filed: 11/01/1999
• Issued: 09/04/2001
• Est. Priority Date: 08/19/1999
• Status: Expired due to Fees

• Current Assignee: Delaware Capital Formation Incorporated (Dover Corporation)
• Original Assignee: Delaware Capital Formation Incorporated (Dover Corporation)
• Inventors: Porter, Don B., Shapiro, Wayne D.
• Primary Examiner(s): Ryznic, John E.
• Application Number:
  US09/430,955
• Time in Patent Office: 673 Days
• Field of Search: 604/77, 604/78, 604/81, 604/73, 604/76, 921/10, 914/61
• US Class Current: 60/477
• CPC Class Codes: F15B 1/265 with pressurised main reservoir
• CPC Class Codes: F15B 15/18 Combined units comprising both motor and pump
• CPC Class Codes: F15B 15/202 Externally-operated valves mounted in or on the actuator
• CPC Class Codes: F16D 41/10 with self-actuated reversing

Abstract

A hydraulic cylinder in which the cylinder head contains a motor-driven fluid pump, fluid reservoir, and a main control valve for the cylinder. The cylinder includes a transfer tube that extends through the center of the cylinder'"'"'s piston and terminates within a hollow ported section of a piston rod. The cylinder head can additionally include two electrically-actuated pilot valves and two pilot-operated check valves. The pilot-operated check valves include structure that, in combination with passages in the cylinder head, cause both pilot-operated check valves to open when pressurized fluid is being directed to one of the pilot-operated check valves by the main control valve.

Claims

1. A hydraulic cylinder comprising:

an elongated body that inwardly contains a piston that is slidable within an interior cavity of said body, wherein said piston divides said cavity into first and second cavity portions, wherein said piston is attached to a first end portion of a piston rod, wherein sliding movement of said piston causes said piston rod to move in a direction parallel to a longitudinal axis of said body; and

a cylinder head located at one end of said body and extending outwardly from said body in a direction substantially parallel to said longitudinal axis of said body, wherein said cylinder head inwardly contains a pump, a motor operatively connected to said pump and to a power source, a fluid reservoir, and a main control valve that is capable of being actuated by a user, wherein when said valve is actuated by a user, pressurized fluid can flow from said pump to said main control valve and then through a passage in said cylinder head and into said first cavity portion.

2. The hydraulic cylinder of claim 1 wherein said cylinder head also contains a pilot valve operatively connected to said main control valve, and wherein said cylinder head additionally contains an electrically-actuable solenoid connected to said pilot valve, wherein said solenoid can control the operation of said pilot valve, and wherein an electrical wire extends out of said cylinder and electrically connects said solenoid to a user-actuable controller, wherein when a user actuates said controller, an electrical signal will be sent to said solenoid via said wire and cause said solenoid to affect said pilot valve in a manner whereby said pilot valve will affect said main control valve to cause pressurized fluid to be sent into said first cavity portion whereby said fluid will apply pressure on a surface of said piston.

3. The hydraulic cylinder of claim 1 wherein said cylinder head also inwardly contains a pilot-operated check valve, wherein said pilot-operated check valve is in a fluid path leading to said first cavity portion.

4. The hydraulic cylinder of claim 1 wherein said piston rod includes a hollow interior area and a port that connects said hollow interior area with an area exterior to the piston rod within said second cavity portion, and wherein a hollow transfer tube extends through a bore in said piston and into said hollow interior area of said piston rod, wherein said transfer tube is connected to said cylinder head and functions to transfer fluid between said main control valve and said second cavity portion.

5. The hydraulic cylinder of claim 4 further comprising a seal in said bore in said piston, wherein said piston is capable of moving relative to said transfer tube wherein said seal functions to prevent fluid from passing around said transfer tube and traveling through said bore from said first cavity portion to said second cavity portion.

6. The hydraulic cylinder of claim 1 wherein a first clevis is secured to said cylinder head and a second clevis is secured to a second end portion of said piston rod.

7. The hydraulic cylinder of claim 1 wherein the fluid reservoir is in the form of a resilient bag.

8. The hydraulic cylinder of claim 1 wherein the fluid reservoir includes an expansible bellows section that enables an internal volume of the fluid reservoir to change to accommodate changes in the amount of fluid retained within said reservoir.

9. The hydraulic cylinder of claim 1 wherein the pump is in the form of a piston pump.

10. A hydraulic cylinder comprising:

an elongated body that inwardly contains a piston that is slidable within an interior cavity of said body, wherein said piston divides said cavity into first and second cavity portions, wherein said piston is attached to a portion of an elongated piston rod, wherein sliding movement of said piston causes said piston rod to move in a direction parallel to a longitudinal axis of said body; and

a cylinder head located at one end of said body and extending outwardly from said body in a direction substantially parallel to said longitudinal axis of said body, wherein said cylinder head inwardly contains a fluid reservoir, a pump, a motor operatively connected to said pump and capable of being connected to a power source, and a main control valve, wherein said pump is capable of providing pressurized fluid to said main control valve, wherein said main control valve can direct fluid from said first cavity portion into said fluid reservoir, and wherein said pump has a fluid inlet that is capable of receiving fluid from said fluid reservoir, wherein said main control valve is capable of being actuated through the actions of an electrical mechanism, wherein said mechanism is electrically connected to a control located exterior to said cylinder, wherein when said valve is actuated by said electrical mechanism in a predetermined manner, pressurized fluid will flow from said main control valve, through a passage in said cylinder head, and into said second cavity portion.

11. The hydraulic cylinder of claim 10 wherein said piston rod includes a hollow interior area and a port that connects said hollow interior area to an area exterior to the piston rod within said second cavity portion, and wherein a hollow transfer tube extends through a bore in said piston and into said hollow interior area of said piston rod, wherein said transfer tube is connected to said cylinder head in a manner whereby fluid can travel between said main control valve and said second cavity portion via said transfer tube.

12. The hydraulic cylinder of claim 10 wherein said cylinder head also contains first and second pilot valves operatively connected to said main control valve, wherein said electrical mechanism is in the form of first and second solenoids, wherein said first pilot valve is operatively connected to said first solenoid and said second pilot valve is operatively connected to said second solenoid, wherein when said control located exterior to said hydraulic cylinder is actuated by a user in a predetermined manner, said second solenoid will become energized and affect said second pilot valve to cause pressurized fluid to be directed to said main control valve and thereby cause said main control valve to direct pressurized fluid into the second cavity portion and cause said piston to move within said body and thereby cause fluid to leave the first cavity portion and flow into said reservoir via said control valve.

13. The hydraulic cylinder of claim 12 wherein said first pilot valve is hydraulically-connected to said main control valve in a manner whereby it can cause said main control valve to direct pressurized fluid into said first cavity portion.

14. The hydraulic cylinder of claim 10 wherein said cylinder head also contains first and second pilot-operated check valves, wherein said first pilot-operated check valve is in a fluid path leading to said first cavity portion, and wherein said second pilot-operated check valve is in a fluid path leading to said second cavity portion, wherein pressurized fluid can be selectively directed to either of said pilot-operated check valves by said main control valve and cause the pilot-operated check valve receiving pressurized fluid to open and allow said fluid to continue to one of said cavity portions of said body.

15. The hydraulic cylinder of claim 14 wherein when pressurized fluid is being directed to one of said pilot-operated check valves by said main control valve, pressurized fluid will also be directed to the other of said pilot-operated check valves, wherein said other of said pilot-operated check valves includes a fluid-actuated opener that will cause said other of said pilot-operated check valves to open and thereby allow displaced fluid from one of said cavity portions to flow through said other of said pilot-operated check valves and be directed to said fluid reservoir.

16. The hydraulic cylinder of claim 14 wherein each of said pilot-operated check valves includes a fluid-operated locking system that can prevent the valve from opening.

17. The hydraulic cylinder of claim 16 wherein each of said pilot-operated check valves includes a movable poppet, and wherein said locking system is in the form of a weep hole located in a side portion of each of said poppets, wherein when said weep hole is exposed to fluid in a passage leading to one of said cavity portions, said weep hole will allow fluid to flow into an otherwise sealed interior area of the associated poppet, wherein once said sealed area of said poppet is filled, movement of the poppet is thereby prevented due to the incompressibility of the fluid located within the poppet.

18. The hydraulic cylinder of claim 10 wherein the fluid reservoir is in the form of a resilient bag.

19. The hydraulic cylinder of claim 10 wherein the fluid reservoir includes an expansible bellows section that enables an internal volume of the fluid reservoir to change in response to changes in the amount of fluid retained within said reservoir.

20. The hydraulic cylinder of claim 10 wherein the pump is in the form of a piston pump.

21. A hydraulic cylinder comprising:

an elongated body that inwardly contains a piston that is slidable within an interior cavity of said body, wherein said piston divides said cavity into first and second cavity portions, wherein said piston is attached to a piston rod, wherein sliding movement of said piston causes said piston rod to move in a direction parallel to a longitudinal axis of said body; and

a cylinder head located at one end of said body, wherein said cylinder head inwardly contains a pump, a motor operatively connected to said pump and connectable to a power source, a fluid reservoir, and a main control valve that is capable of being actuated by a user, wherein when said motor is connected to a power source and said valve is actuated by a user, pressurized fluid can flow from said pump to said main control valve and then through a passage in said cylinder head and into said first cavity portion.

22. The hydraulic cylinder of claim 21 wherein said reservoir is in the form of an expansible tube of resilient material and inwardly contains said pump.

23. The hydraulic cylinder of claim 22 wherein said cylinder head includes a tubular portion that inwardly contains said reservoir.

24. A hydraulic cylinder comprising:

an elongated body that inwardly contains a piston that is slidable within an interior cavity of said body, wherein said cavity is defined by a tubular sidewall, wherein said piston divides said cavity into first and second cavity portions, wherein said piston is attached to a portion of an elongated piston rod, wherein sliding movement of said piston causes said piston rod to move in a direction parallel to a longitudinal axis of said body; and

a cylinder head located at one end of said body, wherein said cylinder head includes an outwardly extending tubular portion that has a diameter no greater than an amount approximately equal to an outer diameter of the sidewall that defines said cavity in said body, wherein said tubular portion is elongated and has a longitudinal axis that is substantially collinear with said longitudinal axis of said body, wherein said cylinder head inwardly contains a fluid reservoir, a pump operatively connected to a power source, and a control valve, wherein said pump and said reservoir are located within said tubular portion of said cylinder head, wherein said pump is capable of providing pressurized fluid to said control valve and has a fluid inlet that is capable of receiving fluid from said fluid reservoir, wherein said control valve is capable of being actuated through the actions of an electrical mechanism, wherein said mechanism is electrically connected to a control located exterior to said cylinder, wherein when said control valve is actuated by said electrical mechanism in a predetermined manner, pressurized fluid will flow from said control valve into said second cavity portion while fluid from said first cavity portion is directed into said fluid reservoir.

25. A hydraulic cylinder comprising:

an elongated body that inwardly contains a piston that is slidable within an interior cavity of said body, wherein said piston divides said cavity into first and second cavity portions, wherein said piston is attached to a portion of an elongated piston rod, wherein sliding movement of said piston causes said piston rod to move in a direction parallel to a longitudinal axis of said body; and

a cylinder head located at one end of said body, wherein said cylinder head inwardly contains a fluid reservoir, a pump operatively connected to a power source, and a control valve, wherein said fluid reservoir is in the form of a resilient bag having a body portion and a distal end portion, wherein said body portion inwardly contains said pump and said distal end portion of said bag is in the form of an expansible bellows that enables an internal volume of the fluid reservoir to change in response to changes in the amount of fluid retained within said reservoir, wherein said pump is capable of providing pressurized fluid to said control valve and has a fluid inlet that is capable of receiving fluid from said fluid reservoir, wherein said control valve is capable of being actuated through the actions of an electrical mechanism, wherein said mechanism is electrically connected to a control located exterior to said cylinder, and wherein when said control valve is actuated by said electrical mechanism in a predetermined manner, pressurized fluid will flow from said control valve into said second cavity portion while fluid from said first cavity portion is directed into said fluid reservoir.

26. The hydraulic cylinder of claim 25 wherein said fluid reservoir is located within an interior area of a tubular, outwardly-extending portion of said cylinder head, wherein the body portion of said resilient bag has a diameter that is complementary to a diameter of said interior area, and wherein said interior area is vented to the ambient atmosphere.

27. A hydraulic cylinder comprising:

an elongated body that inwardly contains a piston that is slidable within an interior cavity of said body, wherein said piston divides said cavity into first and second cavity portions, wherein said piston is attached to a portion of an elongated piston rod, wherein sliding movement of said piston causes said piston rod to move in a direction parallel to a longitudinal axis of said body; and

a cylinder head located at one end of said body, wherein said cylinder head inwardly contains a fluid reservoir, a pump operatively connected to a power source, and a control valve, wherein said fluid reservoir is in the form of an elongated resilient bag that is axially expansible to enable an internal volume of the fluid reservoir to change in response to changes in the amount of fluid retained within said reservoir, wherein said pump is capable of providing pressurized fluid to said control valve and has a fluid inlet that is capable of receiving fluid from said fluid reservoir, wherein said control valve is capable of being actuated through the actions of an electrical mechanism, wherein said mechanism is electrically connected to a control located exterior to said cylinder, and wherein when said control valve is actuated by said electrical mechanism in a predetermined manner, pressurized fluid will flow from said control valve into said second cavity portion while fluid from said first cavity portion is directed into said fluid reservoir.

28. A hydraulic cylinder comprising:

an elongated, tubular body that inwardly contains a piston that is slidable within an interior cavity of said body, wherein said piston is attached to a portion of an elongated piston rod, wherein said body has a longitudinal axis that is substantially collinear with a longitudinal axis of said piston rod;

a cylinder head that extends outwardly from said body, wherein said cylinder head inwardly contains a fluid reservoir, a pump, and a main control valve that is actuated through the action of an electrical mechanism that is also located within said cylinder head, wherein said elongated body and said cylinder head together form an elongated unit having a substantially uniform diameter;

a motor operatively connected to said pump and capable of causing said pump to provide pressurized fluid to said valve;

wherein said main control valve can direct fluid from said first cavity portion into said fluid reservoir, and wherein said pump has a fluid inlet that is capable of receiving fluid from said fluid reservoir; and

wherein said electrical mechanism is electrically connected to a control located exterior to said cylinder, wherein said motor is connected to a source of electrical power located exterior to said cylinder, wherein said motor and said electrical mechanism both receive electrical power via a connection in said cylinder head, and wherein when said valve is actuated by said electrical mechanism in a predetermined manner, pressurized fluid will flow from said main control valve, through a passage in said cylinder head, and into said second cavity portion.