Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Construction or agricultural-type vehicle
Utility Patent
1997-06-20
2001-01-02
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Construction or agricultural-type vehicle
C037S348000, C477S155000, C172S004500, C172S005000, C340S500000, C340S679000, C340S684000
Utility Patent
active
06169948
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a construction machine having a multi-articulated front device, and more particularly to a front control system for a construction machine, e.g., a hydraulic excavator having a front device comprising a plurality of front members such as an arm, a boom and a bucket, which system is adapted for front control, e.g., area limiting excavation control to limit an area where the front device is allowed to move for excavation. The present invention also relates to an area setting method for use in the front control and a control panel for use with the front control system.
2. Description of the Related Art
There is known a hydraulic excavator as a typical one of construction machines. In a hydraulic excavator, front members, such as a boom and an arm, making up a front device are operated by an operator manipulating respective manual control levers. However, because the front members are coupled to each other through articulations for relative rotation, it is very difficult to carry out excavation work within a predetermined area or in a predetermined plane by operating the front members. Also, when excavation work is performed in urban districts and so forth, due care must be paid to keep the front device from interfering with surrounding objects, e.g., electric wires and walls.
In view of the above-mentioned state of art, various proposals for facilitating excavation work or preventing interference between the front device and surrounding objects have been made.
For example, according to JP, A, 4-136324, a slowdown area is set in a position before reaching an entrance forbidden area, and a front device is slowed down by reducing an operation signal input from a control lever when a part, e.g., a bucket, of the front device enters the slowdown area, and is stopped when the bucket reaches the boundary of the entrance forbidden area. Also, this related art employs, as an area setting method, one mode in which the operator moves a bucket end onto the target boundary and pushes a switch there (direct teaching setting mode), or the other mode in which the operator inputs necessary numeral values through numeral input keys (numeral input setting mode).
Further, according to WO 95/30059, an area to be excavated is set beforehand, and a part, e.g., a bucket, of a front device is controlled to slow down its movement only in the direction toward the excavation area when the bucket comes close to the boundary of the excavation area, and to be able to move along the boundary of the excavation area without going out of the excavation area when the bucket reaches the boundary of the excavation area. Also, this related art discloses an area setting method in which the operator moves a bucket end onto the target boundary and pushes a switch there (direct teaching setting mode).
SUMMARY OF THE INVENTION
When the operator sets an area where the front device is forbidden from entering, which one of the above setting modes is more convenient depends on the type of scheduled work.
For example, when the ground should be generally leveled by rough excavation in the work site where an area to be excavated is not especially defined by numerals put on the drawing or the like, it is convenient for the operator to move a bucket end directly to a limit position of the excavation and perform setting operation, e.g., push a button or the like, thereby setting the area based on coordinate values of the bucket end (direct teaching setting). In some work sites, however, the depth by which the ground is to be excavated from the level of a hydraulic excavator on the ground surface is specified in unit of meter. In such a case, it is convenient to set an excavation area by an actual numeral value beforehand (numeral input setting). Furthermore, work of gradually proceeding with excavation from the ground surface and digging up a pipe (water service pipe or the like) buried in earth requires the excavation to be first roughly made to some extent without any control and then finely made under area limiting excavation control from a certain depth. In this case, it is convenient to excavate the ground roughly to some extent without any control, then set the position reached at that time by the direct teaching, setting mode and then proceed with the excavation gradually in steps of several centimeters in such a manner as like carefully peeling off a thin skin while setting the depth in a gradually increasing value with the above set position as a base, thus digging up the target pipe.
However, the above related-art systems include only one area setting means, i.e., means for the direct teaching setting or means for the numeral input setting. This has raised a problem that the operator can neither always select optimum area setting means in any of the work sites nor take appropriate and prompt actions for various types of works.
In addition, during the operation under front control with the area setting described above, it is often desired to cancel the control for a while. For example, work of burring a water service pipe or the like in the ground is carried out with a hydraulic excavator by excavating a predetermined length of trench to a certain depth, then lifting the pipe and installing it in the trench at a predetermined position, and then excavating another length of trench. In other words, trench digging and pipe burring are repeated alternately. When the trench digging in such work is performed under area limiting excavation control, for example, the work is proceeded with in a sequence of excavating a predetermined length of trench, turning off a control start switch on a control panel to bring the area limiting excavation control to an end once, lifting the pipe with a crane for desired installation, turning on the control start switch, and setting the excavation area again to excavate another length of trench. This results in complicated operation and makes the operator feel impatient therewith.
A first object of the present invention is to provide a front control system for a construction machine, an area setting method and a control panel for use with the front control system, by which the operator can always select optimum area setting means in any of work sites and take appropriate and prompt actions for various types of works.
A second object of the present invention is to provide a front control system for a construction machine, which can cancel front control temporarily and simply resume the front control after the temporary cancellation.
(1) To achieve the above first object, the present invention provides a front control system equipped on a construction machine comprising a multi-articulated front device made up of a plurality of front members rotatable in the vertical direction, a plurality of hydraulic actuators for driving respectively the plurality of front members, and a plurality of hydraulic control valves driven in accordance with respective operation signals input from a plurality of operating means for controlling flow rates of a hydraulic fluid supplied to the plurality of hydraulic actuators, the front control system controlling the front device to be moved in a preset area, wherein the front control system comprises first area setting means having a direct setting switch for setting an area where the front device is allowed to move, by direct teaching in response to an instruction from the direct setting switch, second area setting means having a numeral input switch for setting an area where the front device is allowed to move, by inputting a numeral value through the numeral input switch, and setting selection means for selecting one of the first area setting means and the second area setting means.
In the present invention thus constructed, the front control system includes two area setting means, i.e., the first area setting means capable of direct teaching setting and the second area setting means capable of numeral input setting, and can select one of the two area setting means by the setting sele
Fujishima Kazuo
Haga Masakazu
Nakagawa Takashi
Watanabe Hiroshi
Beall Law Offices
Beaulieu Yonel
Cuchlinski Jr. William A.
Hitachi Construction Machinery Co. Ltd.
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