JPH07238576A - Back hoe - Google Patents

Abstract

PURPOSE:To use an operation lever, which performs expansion drive of the arm of an excavation work device, in combination with other operation lever. CONSTITUTION:A back hoe is constituted such a manner that a revolving table is mounted operably revolvingly around a vertical axis on a machine bed on which a pair of right and left running devices are mounted regulatably of a lateral distance, and pressure oil is fed to and discharged from a hydraulic actuator 12 for elevation operation to perform elevation operation of a dozer arranged at the machine bed and a hydraulic actuator 11 for regulating the lateral distance of a running device through a common control valve 15 operated by a single lever 26 from the revolving table side, a flow passage switch valve 16, and a rotary joint 14. In the back hoe, the arm of an excavation work device arranged at the revolving table is expanded and contracted. The arm is expanded and contracted by a hydraulic actuator 25 for expansion and contraction of the arm and the oil passage switch valve 16 is connectable to the control valve 15 through an oil passage by selecting only one of the hydraulic actuator 12 for elevation, the actuator 11 for regulating a lateral distance, and the actuator 25 for expanding and contracting an arm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention includes a machine base having a pair of left and right traveling devices whose left and right distances can be adjusted so that the machine can be rotated about a vertical axis and is equipped with the machine base. A common control valve, a flow path switching valve, and a rotary joint, which are operated by one lever from the swivel side, are provided for a hydraulic actuator for lifting and lowering the dozer and a hydraulic actuator for adjusting the horizontal distance of the traveling device. The present invention relates to a backhoe configured to supply and discharge pressure oil via the backhoe.

[0002]

2. Description of the Related Art Conventionally, as a backhoe of this type, for example, Japanese Patent Application No. 4-283368 previously filed by the present applicant has been proposed.
As proposed in No. 1, it is known that a part of the oil passage is shared between the lifting hydraulic actuator and the left-right distance adjusting actuator in order to reduce the number of oil passages in the rotary joint. .

[0003]

By the way, in the above-mentioned conventional structure, the flow path switching valve is of the two-position switching type, and is different from the hydraulic actuator for elevation and the actuator for adjusting the horizontal distance. It was only switchable. Further, conventionally, in the backhoe, it is proposed that the arm of the excavation work device is configured to be extendable and retractable, and the extension and contraction of the arm can be performed to perform excavation at a location relatively distant from the body or deep excavation. However, in this type of backhoe, the arm is also expanded and contracted by a dedicated hydraulic actuator, and the expansion and contraction operation is performed by a dedicated control valve. Therefore, in the above-mentioned conventional backhoe, the operation lever and the control valve for exclusive use for extending and retracting the arm are provided, so that the cost is high and the operation lever and the control valve are provided. It had become necessary to secure a space for it. The present invention has been made in view of the above circumstances, and a backhoe is simple in structure and inexpensive by making an operating lever or the like for extending and retracting an arm of an excavation work device also serve as another operating lever or the like. The purpose is to be able to configure.

[0004]

In order to achieve the above-mentioned object, the backhoe according to the present invention has the structure described above, in which the arm of the excavation work device provided on the swivel base is configured to be extendable and retractable. The extension / contraction hydraulic actuator drives the extension / contraction of the arm, and the flow path switching valve is controlled by selecting only one of the lifting / lowering hydraulic actuator, the left / right interval adjustment hydraulic actuator, and the arm extension / contraction hydraulic actuator. The characteristic feature is that the valve and the oil passage can be connected. The operation and effect of this characteristic configuration are as follows.

[0005]

In other words, since the flow path switching valve is configured so that it can be connected to the control valve by the oil passage by selecting only one of the lifting hydraulic actuator, the horizontal distance adjusting hydraulic actuator, and the arm extension hydraulic actuator. The hydraulic actuator for arm extension and contraction can be driven by the operation lever and the control valve for selecting the lifting hydraulic actuator and the horizontal spacing adjusting hydraulic actuator to perform lifting and spacing adjustment operations. .

[0006]

Therefore, since the arm can be expanded and contracted by using the operation lever for elevating and lowering the dozer that has been conventionally installed without using a special operation lever, the special lever for expanding and contracting the arm is not required. Since there is no dedicated lever or dedicated control valve, the space around the control section can be increased and the cost can be reduced.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. The backhoe is shown in FIG. This backhoe is provided with a swivel base 4 which is rotatable around a longitudinal axis on a machine base 3 provided with a crawler traveling device 1, 1 as a pair of left and right traveling devices and a dozer 2, and which is mounted on the swivel base 4.
The control unit 5, the driving unit 6, and the excavation work device 7 are equipped and configured.

As shown in FIG. 2, a pair of front and rear support guide portions 8 and 8 formed of a pipe frame in a lateral direction of the machine body are arranged on the machine base 3, and these support guide portions 8, 8 are mounted on the track frames 1 of the pair of left and right crawler traveling devices 1 and 1 in a state in which they are fitted so that they can be slidably guided laterally from the left and right outside.
It is connected before and after 0 and 10. Each track frame 1
A single rod type left-right distance adjusting hydraulic cylinder 11 as a left-right distance adjusting hydraulic actuator is installed between 0 and the machine base 3. On the other hand, the dozer 2 is supported by supporting arms 2A, 2A pivotally supported on the machine base 3, and is operated to be lifted and lowered by a lifting operation hydraulic cylinder 12 as a lifting hydraulic actuator that is connected to the machine base 3.

As shown in FIG. 1, an oil passage between the hydraulic pump 13 and the rotary joint 14 for supplying / discharging pressure oil from the hydraulic pump 13 of the driving portion 6 of the swivel 4 to the machine base 3 is provided. Is an oil as a flow path switching valve composed of a main control valve 15 as a control valve configured to control the supply / discharge direction of pressure oil with one lever 26 and a rotary valve having a 4-port 3-position switching valve configuration. The switching valve 16 is interposed. One of the secondary side ports of the main control valve 15 and the primary side port of the oil passage switching valve 16 are connected by the oil passage 17, and three secondary side ports of the oil passage switching valve 16 are connected. One of the ports
And one of the pressure oil supply / discharge ports of the lifting operation hydraulic cylinder 12 are connected by an oil passage 18.
An oil passage 19 connects one of the three ports of the next side port and one of the pressure oil supply / discharge ports of the hydraulic cylinder 11 for adjusting the left / right spacing. The oil passage 18 and the oil passage 19 are also formed in the rotary joint 14, respectively. Further, the oil passages 20 and 21 respectively connected to the other pressure oil supply / discharge port of the left / right spacing hydraulic cylinder 11 and the other pressure oil supply / discharge port of the lifting operation hydraulic cylinder 12 are connected together. An oil passage 22 connected to the other of the secondary side ports of the main switching valve 15 and formed in the rotary joint 14.
And the oil passages 20 and 21 are connected.

Further, as shown in FIG. 3, the arm 23 of the excavation work device 7 is telescopically structured so that the bucket 24 at the tip thereof can be repositioned relative to the swivel 4 in the perspective direction. In addition, the extension / contraction drive is performed by the extension / contraction hydraulic cylinder 25 as the arm extension / contraction hydraulic actuator. As shown in FIG. 1, one of the pressure oil supply / discharge ports of the expansion / contraction hydraulic cylinder 25 is connected to the oil passage 22, and
The other pressure oil supply / discharge port of the expansion / contraction hydraulic cylinder 25 is one of the three ports of the secondary side port of the oil passage switching valve 16.
Connected with two. Therefore, the three-position switching of the oil passage switching valve 16 is performed by connecting the oil passage 17 to the other pressure oil supply / discharge port of the hydraulic cylinder 25 for expansion and contraction and in the state of connecting the oil passage 17 and the oil passage 18. And the state in which the oil passage 17 and the oil passage 19 are connected to each other can be selected.

With the above construction, the use of only one oil passage switching valve 16 enables the adjustment of the horizontal distance between the traveling devices 1 and 1, the operation of raising and lowering the dozer 2, and the operation of expanding and contracting the arm 23 of the excavation work device 7. Since it can be performed, the hydraulic circuit structure is simple.

[Other Embodiment] As shown in FIG. 4, the control valve 1
5 is an electromagnetic control valve, and the control valve 15 is configured to be controlled and driven by a control signal from the control device 27. The control device 27 detects a detection signal from a sensor switch 28 that detects the operation position of the lever 26 provided in the control section 5, a detection signal from a switching position detection unit 29 that detects the switching position of the oil passage switching valve 16, A detection signal from the left-right spacing detection means 30 for detecting whether the pair of traveling devices 1 and 1 is in a wide state where stable excavation work is possible or in a relatively unstable narrow state, and expansion and contraction of the excavation work device 7. Detection signals from the arm extension detection means 31 for detecting whether the free arm 23 is in the extended state or the shortened state are input. And the control means 27
The switching position means that the oil passage switching valve 16 switches to a position for extending and retracting the arm 23 when the left and right spacing detecting means 30 detects that the traveling devices 1 and 1 have a narrow left and right spacing. When the detection means 29 is detecting, even if the manual lever 26 is operated, a signal for expanding and contracting to the control valve 15 is not output. Also, the control means 27
Indicates that the arm extension detection means 31 detects that the arm 23 is in the extended state, and that the oil path switching valve 16 is switched to the left-right interval adjustment position of the traveling devices 1, 1 to detect the switching position. When the means 29 is detecting, even if the manual lever 26 is operated, the arm 23 cannot be adjusted to the left and right of the control valve 15. Therefore, according to the configuration of this another embodiment, the pair of left and right traveling devices 1,
The arm 23 is prevented from extending unless the horizontal distance of 1 is wide enough for stable excavation work, and the traveling devices 1, 1 are extended when the arm 23 is extended.
I also try not to be able to shorten the left-right spacing.

It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a hydraulic circuit for raising and lowering a dozer, adjusting a horizontal distance of a traveling device, and extending and contracting an arm.

FIG. 2 is a cross-sectional plan view showing a structure for adjusting the horizontal distance of the traveling device.

FIG. 3 is an overall side view showing a backhoe.

FIG. 4 is a circuit diagram showing a hydraulic circuit for lifting and lowering a dozer, adjusting a left-right distance of a traveling device, and extending and retracting an arm according to another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Traveling device 2 Dozer 3 Machine stand 4 Revolving platform 7 Excavation work device 11 Hydraulic actuator for adjusting the horizontal distance 12 Hydraulic actuator for lifting operation 14 Rotary joint 15 Control valve 16 Flow path switching valve 23 Arm 25 Arm actuator hydraulic actuator 26 Lever

Claims (1)

[Claims] 1. A machine base (3) provided with a pair of left and right traveling devices (1), (1) whose left and right distances can be adjusted, and a revolving base (4) mounted so as to be revolvable around a longitudinal axis. A hydraulic actuator (12) for raising and lowering a dozer (2) provided on the machine base (3) and a hydraulic actuator (11) for adjusting the left-right spacing of the traveling devices (1), (1). , One lever (2) from the swivel base (4) side
A backhoe configured to supply and discharge pressure oil via a common control valve (15) operated in 6), a flow path switching valve (16) and a rotary joint (14), the swivel base (4) Arm (23) for excavation work equipment (7)
Is configured to be extendable and retractable, and the arm extension / contraction hydraulic actuator (25) extends / contracts the arm (23), and the flow path switching valve (16) is configured to move up / down the hydraulic actuator (12) and the left / right spacing adjustment. A backhoe configured such that only one of the hydraulic actuator (11) for use and the hydraulic actuator (25) for extending and contracting the arm is selected so that an oil passage can be connected to the control valve (15).