US20140079519A1

US20140079519A1 - Quick Touch Clam Control for Mining Shovel

Info

Publication number: US20140079519A1
Application number: US13/617,494
Authority: US
Inventors: Lane Colin Hobenshield
Original assignee: Caterpillar Inc
Current assignee: Caterpillar Global Mining LLC
Priority date: 2012-09-14
Filing date: 2012-09-14
Publication date: 2014-03-20

Abstract

An improved clam control mechanism for a mining shovel may offer reduced operator fatigue during excavation operations involving the simultaneous and repetitive manipulation of joysticks and switches. The control mechanism may be configured for the loading and unloading of a shovel having a clam rotatable above the shovel, and may include at least two joysticks adapted for a variety of tasks including fore and aft movements, and angular rotation of the shovel. At least one switch may be adapted for moving the clam automatically between fully open and fully closed positions, such that when the switch is briefly pressed a first way, the clam automatically fully opens, and when a switch is briefly pressed a second way, the clam automatically fully closes. On the other hand, if the switch is briefly pressed during either automatic opening or closing of the clam, any movement of the clam may be immediately halted.

Description

TECHNICAL FIELD

This disclosure relates to operational improvements in work machines utilized in excavation processes such as mining operations. More particularly, the disclosure relates to an improved clam operating control feature adapted to reduce operator fatigue during routine manipulations of a mining shovel.

BACKGROUND

Mining shovels are generally employed on worksites to excavate such materials as iron ore, bauxite, limestone, precious metals, and numerous other substances, including dirt. The shovels may be mounted to various work machines, such as so-called excavators, for example. Mining shovels are generally powered by hydraulic fluid pressure, but may alternatively be powered by pneumatic pressure sources. In any event, a generally high-pressure fluid may be utilized for cyclically moving the shovel for repetitively loading and unloading the shovel. The excavated material may generally be transferred to another work machine, for example to an adjacent dump truck for removal from the worksite.
The operation of a mining shovel general involves at least five repetitive actions and/or functions, all directed to the cyclic loading and emptying of the shovel. Once a work machine is optimally situated; i.e., positioned to initiate a mining excavation process, the operator must use at least two separately moveable levers, called joysticks, to successfully carry out the excavation process. One directional movement of a first lever may be employed to horizontally rotate the superstructure of the work machine, including the cab and boom, about the tracks of the work machine, so as to angularly position the boom to initiate shoveling of the material to be excavated. A second directional movement of the first lever may be employed to raise and/or lower the boom so as to move the stick to a position to begin an excavation cycle. A second lever may be employed to accommodate a third directional movement resulting in fore and aft movements of the stick, for example to force the shovel into the excavation material. A fourth directional movement of the second lever may be employed to rotate the shovel relative to the end of the stick. As such, the shovel may be raised to directly engage and capture the material, and/or lowered in a vertical plane to unload the material into another work machine, typically a receiving vehicle, for example, a dump truck.
In combination with the above described joystick movements, a two-way switch must be typically pressed and held to vertically open or close a shovel clam attached to an upper portion of the shovel for unloading or retaining excavated material within the shovel between excavation cycles, as will be appreciated by those skilled in the art. To the extent that such repetitive tasks are associated with work machines generally, not just mining shovels, constant efforts have been made to improve and/or enhance various work machine functions.
For example, U.S. Pat. No. 6,981,833 discloses a first work machine i.e., a harvesting machine, adapted for moving an agricultural product through a conveyor tube for its transfer to a second work machine, such as a vehicle having a receiving bin. The tube may be swung back and forth, from a retracted or stored position, to a position over the bin of the second work machine for enabling the bin to be “topped off” under precise operator control. The vehicle includes a control system having an extend switch and a retract switch, which operates in a both a latched first mode whenever the product conveyor device is inactive, and in an unlatched second mode whenever the conveyor is powered up to transfer grain. In the unlatched mode, if the operator presses the extend or retract switch, the corresponding swinging motion commences upon such contact. However, in the latter mode, the extend or retract motion ceases whenever the operator ceases tactile contact with, i.e. continuous pressing of, the corresponding switch.
It may thus be beneficial to utilize a more easily executed switch control function to accommodate movements of a shovel clam in light of an operator's repetitive manipulations associated with use of a mining shovel, particularly where multiple joy-stick may be involved. A simplified operation may facilitate the operator's ability to better handle repetitive cyclic movements of the shovel apparatus, and thus to reduce operator fatigue during an excavation process.

SUMMARY OF THE DISCLOSURE

In one aspect of the disclosure, a work machine including a shovel may be configured for excavating material. The work machine may include a main body and a base including tracks, with the main body adapted to swivel about the base. The main body may include an operator cab, and may have a boom moveably secured to the main body at one end. The second end of the boom may be vertically movable relative to the main body. A stick may have a first end attached to the second end of the boom, while a second end of the stick may be aftwardly and rearwardly rotatably movable with respect to the boom. A shovel may be rotatably secured to the second end of the stick.
In another aspect of the disclosure, the main body may include a movable clam secured to the shovel; the clam may be positioned above the shovel, and adapted to swivel above the shovel between open and closed positions.
In yet another aspect of the disclosure, the work machine may include a control system configured for loading and unloading the shovel, and the control system may include several moveable levers or joysticks for manipulating the shovel and associated components during an excavation process.
In yet another aspect of the disclosure, a first directional joystick movement may be adapted for angularly positioning the main body relative to the tracks, a second directional joystick movement adapted for raising and lowering the boom, a third directional joystick movement adapted for controlling forward and aft movements of the stick, and a fourth directional joystick movement may be adapted for controlling vertically oriented, angular rotation of the shovel.
In a still further aspect of the disclosure, the control system may include a simple rocker switch configured for quick touch actuation, wherein the clam will automatically fully open or fully close whenever the appropriate (open or close) rocker switch end is quickly pressed and released.
In accordance with a final aspect of the disclosure, whenever the switch may be pressed again, or at any time during either an automatic opening or closing cycle of the clam, any otherwise continued movement of the clam may be immediately halted.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an excavating machine that may incorporate the disclosed clam control system, shown unloading excavated material contents into an adjacent receiving machine.

FIG. 2 is one schematic representation of the disclosed joystick and clam control system.

FIG. 3 is a flowchart of one exemplary operation of the disclosed clam switch control system.

DETAILED DESCRIPTION

Referring initially to FIG. 1, a work machine, such as an excavating machine 10, of a type used for mining, and adapted for digging and removing iron ore, bauxite, limestone, precious metals, and other substances, including dirt, from a construction worksite, is shown. The excavating machine 10 may incorporate an operator cab 12 (shown only fragmentarily and in phantom) secured to, and constituting a part of, a base 16. The base 16 may include an engine, a hydraulic pump unit, and operating controls (none shown). The base 16 may be supported by, and may be transportable on, tracks 14. An extensible and/or rotatable boom 20 may be movably anchored to the base 16, and an articulating stick 22, also variously called a lift arm, may be secured to and supported for movement on the boom 20.
The excavating machine 10 may incorporate a shovel 24 at one end of the stick 22. Joysticks or operating levers (not shown) may be adapted to be controlled by hydraulic cylinder actuators 26 to move the boom 20 relative to the base 16, the stick 22 relative to the boom 20, and to move the shovel 24 relative to the stick 22.
Continuing reference to FIG. 1, a shovel clam 30 may be rotatably secured to the shovel 24. The shovel clam 30 may be raised upwardly from the shovel 24 in the direction of arrow R, as shown, and may include a plurality of teeth 32 adapted to facilitate removal of excavation material from a worksite, such as a mine. The shovel clam 30 may be movable via a dedicated pair of hydraulic cylinder actuators 26, and may be adapted to retain excavation material until time for its release, such as into the refuse bin 34 of an awaiting dump truck 38, as shown.
Referring now to FIG. 2, an operating control system 40 is shown schematically. The control system 40 may include an electronic central processing unit, or CPU 42, and a display unit 44, both situated within the cab 12. The control system 40 may also include a hydraulic pump 46, physically situated apart from the cab 12 but within the base 16 of the work machine 10. The CPU 42 may communicate electronically with a joystick signal interface unit 48 as well as a clam switch signal interface unit 50. The interface units 48 and 50 may function as electronic buses, capable of facilitating electronic data transfers between clam switches 52, 54 and various signal-generating directional joystick movements 60, 62, 64, and 66, the latter triggered by unidirectional movements of a pair of joysticks (not show) positioned within the cab 12 for manipulation by a cab operator.
The switches 52 may provide for respective automated opening and closing operations of the shovel clam 30 (FIG. 1). The switch 54 may operate as an override to immediately halt any movement of the clam 30 whenever the switch 54 may be actuated during any closing or opening operation of the clam 30. In the disclosed control system 40, the open and close switches 52 may be embodied as a single rocker switch (not shown), while the switch 54 may be an entirely separate unit, although interfaced with the open and close switches 52. Alternatively, the switches 52, 54 may be embodied as a single unit, with the rocker switch configured to have clam opening and closing functions triggered by pressing opposite ends of the rocker, while the halting function may be configured to be triggered only while either of the opening and closing functions are actually taking place. For example, in the latter instance if either the opening or closing end of a rocker switch 52 is pressed, a quick press of either of those two switch ends could trigger the halting function.
Continuing reference to FIG. 2, the various signal-generating directional joystick movements 60, 62, 64, and 66 may be functionally embodied in a pair of joysticks, and may be described as follows. Directional joystick movement 60 may be a side to side motion of a first joystick (not shown). That movement, identified in the schematic as J-1, may cause the base 16 to swivel on the tracks 14. Directional joystick movement 62, identified in the schematic as J-2, may be a forward-aft motion of the same first joystick, producing a vertical movement; i.e. the raising and lowering, of the boom 20. Directional joystick movement 64, identified in the schematic as J-3, may be a forward-aft motion of a second joystick (not shown), resulting in a forward aft motion of the stick 22. Finally, directional joystick movement 66, identified in the schematic as J-4, may be a side to side motion of the same second joystick, resulting in a vertical rotation of the shovel 24.
The disclosed control system 40 may incorporate additional enhancements. For example, the opening and closing functions of the clam 30 may be associated with a so-called “ramp-down” feature, wherein hydraulic actuating cylinders 26 associated with the clam 30 may utilize a control valve system configured for slowing the flow of hydraulic fluid as the ends of cylinder travel, associated with the opening and closing limits of clam movement, are approached, whether during cylinder extension or retraction. This feature may soften normally otherwise harsh loads associated with “hitting the stops”, and thus may be effective to avoid damage to cylinder end parts and/or to otherwise prolong the actuator cylinder life. As such, the hydraulic cylinder actuators 26 may incorporate position limit or proximity sensors, or may alternatively be configured to slow the flow of hydraulic fluid whenever a limit switch is tripped.
Although the drawings and description herein may appear to be limited to the specific embodiments disclosed, those skilled in the art may appreciate that numerous variations may fall within the spirit and scope of the appended claims.

INDUSTRIAL APPLICABILITY

In use, the disclosed control system 40 may be adapted for an excavating machine 10, such as a mining shovel. The control system 40 may be beneficial for reducing operator errors, as well as for potential reductions in damages to a clam 30, a shovel 24, and even more generally to the excavating machine 10. In addition, the control system 40 may offer a general reduction in operator fatigue. Moreover, the improved clam switch control function, utilizing the switch signal interface unit 50, may support a quicker learning curve for new operators.
As disclosed, latched mode switches 52, 54 may be embodied in a two-way rocker type switch having open and close positions at opposite ends of the rocker. In a latched mode, the switches may be actuated via a quick touch; conversely in a so-called unlatched mode, such switches may require a constant tactile pressure for assuring continued movement of the clam 30 during an opening or closing sequence. The switches 52, 54 may thus be configured for being touched briefly at one end, or in a first way, to initiate an automatic fully open clam function, and at an opposite end, or in a second way, for initiating an automatic fully close clam function. A quick touch of a clam control switch 52, 54 as defined herein provides that any clam opening and closing sequence will continue after a respective open or close switch has been briefly actuated by a touch, irrespective of any need to press and hold the switch continuously during such opening or closing operation.
A typical excavation operation associated with a mining shovel may extend over several workdays. Providing a quick touch clam control mechanism for a mining shovel to avoid an operator's having to continuously press and hold a button numerous times per cycle, particularly while simultaneously manipulating a pair of joysticks, may offer significant operator fatigue relief.
Referring now to FIG. 3, an exemplary operation of the clam switch controls, utilizing the disclosed functional open and close switches 52 and the clam halt override switch 54, may now be described as follows.
In the following description, the meanings of “no” and “not” are synonymous. Upon initialization via an operator in the cab 12, the CPU 42 may initially make inquiry as to whether the above-described joystick and switch controls are active. If the controls are not active, the CPU may reroute the same inquiry, per the loop shown, until the controls become active.
If and when the controls are or have become active, the CPU may next inquire whether the clam is fully open. If not, the CPU may ask whether the open switch has been pressed. If not, the CPU may again reroute the inquiry to determine whether the controls are active, per the loop shown. If yes, the CPU may command the clam to fully open. Once the clam begins to open, the CPU may inquire as to whether the close or open switch has been pressed while the clam is opening.
If not, the CPU will continue to command the clam to fully open. If either the close or open switches have been pressed while the clam is opening, the CPU will command the clam to immediately halt any further motion. Once the clam has been halted, the CPU will reroute the inquiry back to whether or not the controls are active, as per the loop shown.
On the other hand, if the response to whether the claim is fully open is yes, the CPU may next inquire whether the close switch has been pressed. If not, the CPU may reroute the inquiry to determine whether the controls are active, per the loop shown. If yes, the CPU may command the clam to fully close. While closing, the CPU may inquire as to whether either of the close or open switches has been pressed while the claim is closing.
If not, the CPU will continue to command the clam to fully close. On the other hand if yes, the CPU will command the clam to halt. Once the clam has halted, the CPU will once again reroute the inquiry back to whether or not the controls are active, as per the loop shown.
A method of providing a quick touch clam control for a work machine having a mining shovel clam 30 may include:
providing a CPU, a plurality of joysticks, and a plurality of switches, and configuring the CPU to interface with the joysticks and switches through respective joystick and clam switch bus signal interface units;
providing a system of signals to be generated from the joysticks in accordance with a set of predetermined directional joystick movements, and having the signals read by the CPU through the joystick bus signal interface unit;
providing a system of signals to be generated from predetermined switch positions in accordance with selective switch movements, and having the signals read by the CPU through the switch bus signal interface unit;
configuring the switches to control a shovel clam, such that the shovel clam may be either automatically fully opened or fully closed by briefly touching a respective open or a close switch; and
providing a halt switch override function, such that any automatic movement of the shovel clam is immediately halted by briefly touching either the open or close switch during any open or close movement of the shovel clam.
Although only one generally described method of forming a quick touch clam switch control system has been disclosed herein, numerous other variations may fall within the spirit and scope of this disclosure. For example, a separate control apparatus may be included and configured to change the timing of fully open and fully closed automatic clam sequences, as for example to offer a range of opening and closing speeds of clam movement between clam position limits
As another example, the described latched switch functionality may be an adjunct to, rather than a replacement of, an unlatched clam switch arrangement, the latter requiring the pressing and holding of the clam switch for continuous movement of the clam between respective open and close position limits In the unlatched arrangement, clam movement would be automatically halted upon an operator's physical release of the switch.

Claims

What is claimed is:

1. A work machine including a shovel adapted for excavating material, the work machine comprising:

a main body affixed to and adapted to swivel about a movable base, the main body including an operator cab and a boom moveably secured to the main body, and wherein one end of the boom is vertically movable relative to the main body;

the main body further including a stick, wherein one end of the stick is aftwardly and rearwardly movably attached to the other end of the boom, and wherein the shovel is vertically rotatably secured to the stick at an opposite end of the stick;

the main body further including a movable clam secured to the shovel, the clam being positioned above the shovel and adapted to swivel between open and closed positions over the shovel;

a control system configured for loading and unloading the shovel, the control system including a plurality of joysticks, each configured for predetermined directional movements, each movement adapted for cyclic positioning of the shovel;

the control system further configured for moving the clam automatically between fully open and fully closed positions, the control system including at least one switch adapted to be briefly pressed a first way to cause the clam to automatically and fully open, and to be briefly pressed a second way to cause the clam to automatically and fully close;

wherein if the switch is briefly pressed either way at any time during either automatic opening or closing of the clam, operation of the clam is immediately halted.

2. The work machine of claim 1, further comprising a separate apparatus for changing speeds of any automatic clam movements between open and closed clam positions.

3. The work machine of claim 1, further comprising a first directional joystick movement adapted for angularly positioning the main body relative to the moveable base, and a second directional joystick movement adapted for raising and lowering the boom.

4. The work machine of claim 3, further comprising a third directional joystick movement adapted for controlling forward and aft movements of the stick, and a fourth directional joystick movement adapted for controlling vertically oriented, angular rotation of the shovel.

5. The work machine of claim 3, wherein the first and second directional joystick movements are configured to be carried out by a first joystick.

6. The work machine of claim 4, wherein the third and fourth directional joystick movements are configured to be carried out by a second joystick.

7. The work machine of claim 1, further comprising at least one hydraulic cylinder actuator configured for moving the clam relative to the shovel, and wherein the actuator includes a ramp-down feature.

8. The work machine of claim 7, wherein the ramp-down feature includes at least one proximity sensor.

9. The work machine of claim 1, wherein the at least one switch is a two-way rocker switch configured for opening and closing the clam.

10. A control system for a machine having a main body and a base including tracks, the main body being adapted to swivel horizontally and angularly relative to the base, the main body including an operator cab and a boom vertically movable relative to the main body; the main body further including a stick movably attached to the boom at a first end of the boom, and having a shovel vertically rotatably secured to the stick at a second end of the boom; the main body further including a movable clam secured to the shovel, the clam being positioned above the shovel, the clam adapted to swivel between open and closed positions over the shovel;

wherein the control system is configured for loading and unloading the shovel, the control system including a plurality of joysticks, each configured for predetermined directional movements, each movement adapted for cyclic positioning of the shovel, the control system further including at least one switch adapted for moving the clam automatically between fully open and fully closed positions, such that when a switch is briefly pressed a first way, the clam automatically fully opens, and when a switch is briefly pressed a second way, the clam automatically fully closes;

11. The control system of claim 10, further comprising a separate apparatus for changing speeds of any automatic clam movements between open and closed clam positions.

12. The control system of claim 10, further comprising a first directional joystick movement adapted for angularly positioning the main body relative to the moveable base, and a second directional joystick movement adapted for raising and lowering the boom.

13. The control system of claim 12, further comprising a third directional joystick movement adapted for controlling forward and aft movements of the stick, and a fourth directional joystick movement adapted for controlling vertically oriented, angular rotation of the shovel.

14. The control system of claim 12, wherein the first and second directional joystick movements are configured to be carried out by a first joystick.

15. The control system of claim 13, wherein the third and fourth directional joystick movements are configured to be carried out by a second joystick.

16. The control system of claim 10, further comprising at least one hydraulic cylinder actuator configured for moving the clam relative to the shovel, and wherein the actuator includes a ramp-down feature.

17. The control system of claim 16, wherein the ramp-down feature includes at least one proximity sensor.

18. The control system of claim 10, wherein the at least one switch is a two-way rocker switch configured for opening and closing the clam.

19. A method for providing a quick touch clam control for a work machine having a shovel clam, comprising:

providing a CPU, a plurality of joysticks, and a plurality of switches, and configuring the CPU to interface with the joysticks and switches through respective joystick and clam switch bus interfaces;

providing a system of signals to be generated from the joysticks in accordance with directional joystick movements, and having the signals read by the CPU through the joystick bus interface;

providing a system of signals to be generated from the switches in accordance with selective switch movements, and having the signals correspondingly read by the CPU through the switch bus interface;

configuring the switches to control a shovel clam;

wherein the shovel clam may be either automatically fully opened or fully closed by briefly touching an open or a close switch, respectively.

20. The method of claim 19, wherein if the switch is briefly pressed at any time during either automatic opening or closing of the clam, operation of the clam is immediately halted.