Power shovel having isolated hydraulic dipper actuator

• US 8,935,865 B2
• Filed: 01/23/2013
• Issued: 01/20/2015
• Est. Priority Date: 01/23/2013
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Bienfang, David Thomas, Szpek, Frank Richard Jr.
• Primary Examiner(s): PEZZUTO, ROBERT ERIC
• Application Number:
  US13/748,097
• Publication Number:
  US 20140205414A1
• Time in Patent Office: 727 Days
• Field of Search: 373/98, 37442-445, 371/95, 374/66, 414/565, 414/699, 414/706, 414/715, 414/726, 604/69, 188/217, 188/312, 188/317, 294/119.4, 294/192
• US Class Current: 37/445
• CPC Class Codes: E02F 3/4075 Dump doors; Control thereof
• CPC Class Codes: E02F 3/46 with reciprocating digging or scraping elements moved by cables or hoisting ropes ; Drives or control devices therefor E02F3/205, E02F3/905 take precedence
• CPC Class Codes: E02F 9/2217 with energy recovery arrangements, e.g. using accumulators, flywheels

Abstract

A hydraulic system for a power shovel may have a cylinder operatively connectable to a dipper door of the power shovel, a reservoir located at and fluidly connected to the cylinder, and an accumulator located at and fluidly connected to the cylinder in parallel with the reservoir. The hydraulic system may further have a control valve disposed between the cylinder, the reservoir, and the accumulator. The control valve may be movable to selectively direct fluid from the cylinder into the accumulator and fluid from the reservoir into the cylinder.

Claims

1. A hydraulic system for a power shovel, comprising:

a cylinder operatively connectable to a dipper door of the power shovel;

a reservoir located at and fluidly connected to the cylinder;

an accumulator located at and fluidly connected to the cylinder in parallel with the reservoir; and

a control valve disposed between the cylinder, the reservoir, and the accumulator, the control valve being movable to selectively direct fluid from the cylinder into the accumulator and fluid from the reservoir into the cylinder.

2. The hydraulic system of claim 1, wherein at least one of the reservoir and the accumulator is mountable to a dipper body of the power shovel.

3. The hydraulic system of claim 1, wherein the reservoir and the accumulator are fluidly connected to a single chamber of the cylinder.

4. The hydraulic system of claim 1, wherein the cylinder is a single-acting cylinder.

5. The hydraulic system of claim 1, wherein the control valve is further movable to selectively direct fluid from the accumulator into the cylinder.

6. The hydraulic system of claim 1, wherein:

the control valve is a first control valve; and

the hydraulic system further includes;

an auxiliary actuator; and

a second control valve configured to direct fluid from the accumulator into the auxiliary actuator and from the auxiliary actuator into the reservoir.

7. The hydraulic system of claim 1, wherein motion of the dipper door is the sole source of power for pressurizing fluid in the hydraulic system.

8. The hydraulic system of claim 1, wherein the cylinder is connectable between a dipper body and a base edge of the dipper door.

9. A hydraulic system for a power shovel, comprising:

a cylinder operatively connectable between a dipper body and a base edge of a dipper door;

an accumulator fluidly connected to the cylinder; and

a control valve disposed between the cylinder and the accumulator, the control valve being movable to selectively actuate the cylinder to release and lock pivoting movement of the dipper door.

10. The hydraulic system of claim 9, wherein the accumulator is mountable to the dipper body.

11. The hydraulic system of claim 9, wherein the accumulator is fluidly connected to a single chamber of the cylinder.

12. The hydraulic system of claim 9, wherein the cylinder is a single-acting cylinder.

13. The hydraulic system of claim 9, wherein the control valve is further movable to selectively direct fluid from the cylinder into at least one of the accumulator and from the accumulator into the cylinder.

14. The hydraulic system of claim 13, wherein:

the control valve is a first control valve; and

the hydraulic system further includes;

an auxiliary actuator; and

a second control valve configured to direct fluid from the accumulator into the auxiliary actuator and from the auxiliary actuator into a low-pressure reservoir.

15. The hydraulic system of claim 9, wherein motion of the dipper door is the sole source of power for pressurizing fluid in the hydraulic system.

16. A power shovel, comprising:

a body;

a boom pivotally connected at a base end to the body;

a dipper handle pivotally connected at a base end to a midpoint of the boom;

a dipper pivotally connected to a distal end of the dipper handle, the dipper having a dipper body and a dipper door pivotally connected at a base edge to the dipper body;

a single-acting cylinder connected at a first end to the dipper body;

a link connecting an opposing second end of the single-acting cylinder to the base edge of the dipper door;

a reservoir located at the dipper and fluidly connected to the single-acting cylinder;

an accumulator located at the dipper and fluidly connected to the single-acting cylinder in parallel with the reservoir;

a first control valve disposed between the single-acting cylinder, the reservoir, and the accumulator, the first control valve being movable to selectively direct fluid from the single-acting cylinder into the accumulator and fluid from the reservoir into the single-acting cylinder;

an auxiliary actuator; and

a second control valve disposed between the accumulator and the auxiliary actuator, the second control valve being movable to selectively direct fluid from the accumulator to the auxiliary actuator and from the auxiliary actuator to the reservoir.

17. A method of operating a power shovel, comprising:

releasing fluid from a cylinder to allow a dipper door of the power shovel to pivot in a first direction under the force of gravity;

accumulating high-pressure fluid discharged from the cylinder during pivoting of the dipper door in the first direction; and

directing low-pressure fluid from a reservoir into the cylinder during pivoting of the dipper door in a second direction under the force of gravity.

18. The method of claim 17, further including hydraulically locking the cylinder to inhibit pivoting of the dipper door.

19. The method of claim 18, further including:

directing accumulated high-pressure fluid to an auxiliary actuator; and

returning low-pressure fluid to the reservoir.

20. The method of claim 19, wherein motion of the dipper door is the sole source of power for pressurized fluid in cylinder.