JPH10102965A - Vertical hole drilling machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent interference between a boom and a front frame and to improve operability and safety. SOLUTION: This vertical hole drilling machine includes a front frame, which carries a kelly-bar rotary drive, and a boom, and is designed to drill a vertical hole using a drilling bucket. In this case, a boom elevating cylinder 1 and a frame elevating cylinder 2 are installed on a self-traveling vehicle main body, and a connecting line 15 provided with operation check valve 3a, 3c and a connecting line 16 provided with operation check valves 3b, 3d are communicated to the boom elevating cylinder 1, during the expansion and contraction of the boom elevating cylinder 1, respectively, so that pressure oil in the boom elevating cylinder 1 is forced into the frame elevating cylinder 2; the connecting lines 16, 15 are communicated to each other to discharge the pressure oil in the frame elevating cylinder 2 into the boom elevating cylinder 1. Therefore, as the boom elevating cylinder 1 expands and contracts the frame elevating cylinder 2 can also be made to expand and contract without bringing the front frame into contact with the boom.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a boom mounted on a base machine so as to be able to undulate, and a front frame mounted on the base machine so as to be able to be undulated and mounted with a keriba rotary drive. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical excavator, such as an earth drill, which excavates a vertical hole by a vertical excavating means such as an excavating bucket by being lowered while being rotated.

[0002]

2. Description of the Related Art In civil engineering and construction work, in order to increase the bearing capacity of a structure to the ground, a pit is excavated to a good underground area of the ground, and reinforced concrete is poured into the pit to mount a foundation pile. The so-called cast-in-place pile method is being implemented. Conventionally, a vertical excavator called an earth drill is commonly used in such a cast-in-place pile method. This earth drill machine is equipped with a boom that can be raised on the body of the self-propelled vehicle that is the base machine, and a front frame that is installed on the base machine so that it can be raised and lowered and that has a kelly bar rotation drive device. At the same time, an excavation bucket as a pit excavation means is attached to the lower end of the keriba, and the keriba is lowered while being rotationally driven by the keriba rotary drive device, so that the pit is excavated in the ground with the excavation bucket. It was done. The present invention seeks to improve this excavator.

An example of a conventional vertical excavator to be improved by the present invention will be described with reference to FIG. FIG. 4 is a side view showing an overall image of a pit excavator according to an embodiment of the present invention. The vertical excavator shown in FIG. 4 is a general earth drill.

In FIG. 4, reference numeral 20 denotes a main body of a crawler type self-propelled vehicle serving as a base machine; 21, a boom standing upright on the self-propelled vehicle main body 20; A front frame which is supported to be capable of ascending and descending and which is equipped with a keliva rotation drive device 25 which will be described later;
Numeral 3 denotes a kerry bar which is hung on a rope 23a hung around a boom 21 and 24 is a kerry bar 2 which is hung.
An excavation bucket as a vertical excavation means attached to the lower end of 3, 25 is a kerry bar rotation drive device for rotating and driving a kerry bar 23, and 26 is a hydraulic cylinder mounted in the boom 21 and raising and lowering the front frame 22. . In addition, the earth drill machine has a crane function to perform the work of suspending the concrete pouring trummy pipe and the reinforcing steel for placing the reinforced concrete after excavating the pit, so that the suspended load can be suspended. And a winch for winding the rope.

[0005] The boom 21 is installed so as to be able to descend by pivotally supporting the self-propelled vehicle main body 20.
It can be raised by winding and rewinding a with a boom hoisting winch. Front frame 22
Is attached to one end of a frame hoisting rope 22a. The frame hoisting rope 22a is guided into the boom 21 via a pulley 22b, and is attached to a rod end of a hydraulic cylinder 26 mounted in the boom 21. 26a (sheave block). And
The other end of the frame hoisting rope 22a is fixed to the front frame 22 again after being hung around the pulley 26a.
Therefore, when the hydraulic cylinder 26 is expanded and contracted, the frame up-and-down rope 22a moves in the direction of being pulled or loosened via the pulley 26a of the hydraulic cylinder 26 to make the front frame 22 up and down.

The excavation bucket 24 has a cutter for excavation on the lower surface of the bottom cover, so that excavated earth and sand can be taken into the inside, and the excavated earth and sand can be discharged by opening the bottom cover as shown in the figure. It has become. The kelly bar rotation drive device 25 applies a rotation force to the excavation bucket 24 by inserting the kelly bar 23 into the torque transmission unit and driving the krill bar 23 to rotate. Accordingly, when the rope 23a is gradually fed out while rotating the kelly bar 23 by the kelly bar rotation drive device 25 to apply a thrust to the excavation bucket 24 by its own weight such as the kelly bar 23 and the excavation bucket 24, the excavation bucket 24 removes the excavated earth and sand. Drill into the ground while taking in and excavate the pit. Further, when a predetermined amount of excavated soil is accumulated in the excavation bucket 24 in the process of excavating underground, the rope 23a is wound up, the excavation bucket 24 is pulled up to the ground, and the excavated earth and sand is discharged. In an earth drill machine, a pit having a predetermined depth is drilled by repeating these steps.

[0007] In a vertical excavator such as an earth drill, there is a case where the boom 21 must be tilted forward, for example, when an operation of suspending a tremy tube or a reinforcing bar is performed. In such a case, if the front frame 22 is not also tilted forward in accordance with the tilt of the boom 21, the boom 21
Strikes the front frame 22 and interferes with each other. For this reason, in the conventional pit excavator, as described above, by connecting the front frame 22 to the boom 21 with the frame hoisting rope 22a, the fall of the front frame 22 is restrained by the frame hoisting rope 22a. Front frame 22 is boom 2 by its own weight
1 so as to lean forward following the forward leaning operation of the boom 21.
And the front frame 22 are prevented from interfering with each other.

On the other hand, when the excavation work is performed while the frame hoisting rope 22a connected to the front frame 22 is tensioned, various impacts and loads caused by the excavation work are transmitted from the front frame 22 to the boom 21 through the frame hoisting rope 22a. This causes the boom 21 to swing. Since the boom 21 may bend more due to this swing, when performing excavation work, the front frame 22 is set to a posture suitable for excavation work, and then the front frame 22 is connected to a separately prepared wire rope ( A hanging rope) is connected to the tip of the boom 21 to maintain its posture, and the frame hoisting rope 22a is slackened so that impact and load are not transmitted to the boom 21 via the frame hoisting rope 22a. .

[0009]

The conventional pit excavator is
By the method as described above, the boom 21 is tilted when the boom is tilted forward.
And the front frame 22 can be prevented from interfering with each other, and the impact or load during excavation work can be prevented from being transmitted to the boom 21. This was desirable in this respect, but there was a problem in workability. . That is, when working with a conventional pit excavator, two types of ropes, a frame undulating rope 22a and a wire rope (suspension rope), must be handled, and work such as connecting and disconnecting ropes must be performed. The handling was very complicated. In addition, since these operations must be performed by the operator on the upper portion of the front frame, the operations are troublesome, and the operation is performed at a high place, and there is a problem in terms of operation safety. .

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art, and its technical problem is that interference between the boom and the front frame can be prevented, and workability and safety can be improved. It is an object of the present invention to provide a vertical excavator having good operability.

[0011]

SUMMARY OF THE INVENTION The above object of the present invention is as follows.
Equipped with a boom that can be set up and down on the base machine and a front frame that can be set up and down on the base machine and equipped with a keliver rotation drive unit. In a pit excavator designed to excavate a pit by means, a boom raising / lowering cylinder for raising / lowering a boom and a frame raising / lowering cylinder for raising / lowering a front frame are installed on a base machine, respectively, and the bottom side of the boom raising / lowering cylinder and the frame A connecting line connecting the rod side of the cylinder and a discharge line discharging the pressurized oil on the bottom side of the frame up-and-down cylinder are provided, and when the boom is lowered and the boom is lowered, the connecting line is connected. And pressurized oil on the bottom side of the boom hoist cylinder to lock the frame hoist cylinder. And pressurized oil is discharged from the bottom side of the frame up-and-down cylinder by communicating with the discharge pipe, so that the front frame does not hit the boom in conjunction with the reduction of the boom up-and-down cylinder. In such a way that the frame up-and-down cylinder is reduced. "

Since the vertical excavator according to the present invention employs such technical means, when the boom raising / lowering cylinder is contracted and the boom is operated in the downward direction, the connecting pipe and the discharge pipe are connected. Thus, the pressure oil on the bottom side of the boom hoist cylinder flows into the rod side of the frame hoist cylinder through the connection pipe, and the pressure oil on the bottom side of the frame hoist cylinder is discharged through the discharge pipe. As a result, the frame up-and-down cylinder also shrinks in conjunction with the reduction of the boom up-and-down cylinder, and the front frame moves in the down direction while being driven so as not to interfere with the boom.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will now be described with reference to FIGS. 1 to 3 showing embodiments of how the present invention is actually embodied. I do. FIG. 1 is a side view schematically showing an overall image of a vertical excavator according to an embodiment of the present invention, FIG. 2 is a hydraulic circuit diagram relating to a vertical excavator according to an embodiment of the present invention, and FIG. It is an operation chart figure about a shaft excavator of an embodiment of the present invention. FIG.
In FIG. 2 and FIG. 2, the parts denoted by the same reference numerals as those in FIG. 4 represent the same parts as those in FIG. The pit excavator according to the embodiment of the present invention includes a boom 21 installed on a crawler-type self-propelled vehicle body 20 as a base machine so as to be able to undulate, and a kelly bar rotation drive device installed undulatingly on the self-propelled car body 20. And a front frame 22 on which a pit 25 is mounted. The pit is digged by a digging bucket 24 as pit digging means by lowering the keriba 23 while rotating and driving the keriba 23 by a keriba rotary driving device 25. Is the same as the conventional excavator of FIG.

Therefore, the characteristic technical contents of the vertical excavator according to the embodiment of the present invention will be described. As described above, in the conventional vertical excavator, the boom 21 is connected to the boom hoisting rope 21a and the boom hoist. While the front frame 22 is raised and lowered with the winch and the frame lifting rope 22a and the hydraulic cylinder 26, the vertical excavator according to the present embodiment, as shown in FIG. The frame 22 is raised and lowered by the boom lifting cylinder 1 and the frame lifting cylinder 2 respectively. Therefore, the boom hoist cylinder 1 is axially attached to the boom 21 and the motor vehicle body 20, and the frame hoist cylinder 2 is axially mounted to the front frame 22 and the motor vehicle body 20, and the boom hoist cylinder 1 and the frame hoist cylinder 2 was installed in the self-propelled vehicle body 20. The pit excavator of this embodiment is based on such a structure, and its hydraulic drive circuit is provided with a unique device as shown in FIG.

The technical contents of this point will be described with reference to FIG. 2. In FIG. 2, reference numeral 9 designates the direction of the flow of the pressure oil so that the boom hoist cylinder 1 expands and contracts by switching from a neutral position to a right position or a left position. A directional control valve for a boom hoist cylinder of a pilot type that controls the hydraulic pressure for controlling the direction of the flow of pressure oil so as to expand and contract the frame hoist cylinder 2 by similarly switching from a neutral position to a left position or a right position. A direction switching valve for a pilot type frame up / down cylinder, 11 is a first main line connecting the rod side of the boom up / down cylinder 1 to a secondary side of the boom up / down cylinder direction switching valve 9, and 12 is a boom up / down cylinder 1 The second main line connecting the bottom side of the cylinder and the secondary side of the direction switching valve 9 for the boom hoisting cylinder, 13 is the frame hoisting cylinder 2
Directional control valve 10 for rod side and frame up / down cylinder
A third main line 14 connects the bottom side of the frame up / down cylinder 2 to the secondary side of the direction switching valve 10 for the frame up / down cylinder. The directional control valve 9 for the boom hoisting cylinder and the primary side of the directional control valve 10 for the frame hoisting cylinder both have an oil supply passage for supplying hydraulic oil pressure and a return oil from the actuator. An oil discharge passage for discharging the pressurized oil to the oil tank is connected. The second main line 12 and the fourth main line 14 are provided with a counter balance valve 4 and a counter balance valve 5, respectively, in order to prevent the boom hoisting cylinder 1 and the frame hoisting cylinder 2 from descending by their own weights in the extended state. Provided.

The directional control valve 9 for the boom hoist cylinder is
When the supply / discharge of the pressure oil of the boom hoist cylinder 1 is stopped at the neutral position and switched to the left position, the hydraulic oil of the hydraulic pump is supplied to the rod side of the boom hoist cylinder 1 through the first main line 11 and the boom hoist cylinder When the pressure oil on the bottom side of 1 is discharged to the oil tank through the second main line 12 and switched to the right position, the pressure oil of the hydraulic pump is supplied to the bottom side of the boom hoist cylinder 1 through the second main line 12 The flow of the pressure oil is controlled so that the pressure oil on the rod side can be discharged to the oil tank through the first main line 11. Therefore, when switching to the left position, the boom hoist cylinder 1
When the boom 21 is moved down, the boom 21 is operated in the downward direction, tilted forward and switched to the right position, the boom up / down cylinder 1 is extended, and the boom 21 is operated in the upright direction. Similarly, the directional control valve 10 for the frame up / down cylinder
When the supply / discharge of the pressurized oil of the frame up / down cylinder 2 is stopped at the neutral position and switched to the right position, the third main line 1
The pressure oil is supplied and discharged through the third and fourth main lines 14, respectively, and when switched to the left position, the pressure oil is supplied and discharged so that the pressure oil can be supplied and discharged through the fourth main line 14 and the third main line 13, respectively. Control the flow. Therefore, when switching to the left position and the right position, the frame up-and-down cylinder 2 is extended and contracted to operate in the upright and forwardly inclined directions, respectively.

Reference numeral 15 denotes a connecting pipe connecting the rod side of the boom hoist cylinder 1 to the bottom side of the frame hoist cylinder 2, and reference numeral 16 denotes a connection connecting the bottom side of the boom hoist cylinder 1 to the rod side of the frame hoist cylinder 2. It is a pipeline. A hydraulic pilot-operated check valve 3a for flowing hydraulic oil only in the direction of the rod of the boom hoist cylinder 1 when not operating, and a hydraulic oil for flowing only in the bottom direction of the frame hoist cylinder 2 when not operating. Operate the check valve 3c of the hydraulic pilot operation,
It is provided on the rod side of the boom hoist cylinder 1 and on the bottom side of the frame hoist cylinder 2. An operating check valve 3 operated by a hydraulic pilot that allows pressure oil to flow only toward the bottom side of the boom hoist cylinder 1 when not operating is connected to the connection pipe line 16.
b and a hydraulic pilot-operated check valve 3d for allowing hydraulic oil to flow only in the direction of the rod of the frame up-and-down cylinder 2 when not in operation is provided on the bottom side of the boom up-and-down cylinder 1 and the rod side of the frame up-and-down cylinder 2, respectively. .

Therefore, in order to reduce the size of the boom hoist cylinder 1, the direction switching valve 9 is switched to the left position to supply the hydraulic oil of the hydraulic pump to the rod side of the boom hoist cylinder 1 through the first main line 11 and operate the hydraulic pump. When the check valve 3b is operated, the return oil on the bottom side of the boom hoist cylinder 1 is diverted to the second main pipe 12 and the connecting pipe 16, and the pressure oil diverted to the connecting pipe 16 is supplied to the frame hoist cylinder 2 Flowing into the rod side, frame undulating cylinder 2
Try to reduce. Similarly, when the directional control valve 9 is switched to the right position and the operating check valve 3a is operated to extend the boom hoist cylinder 1,
The return oil on the rod side of the boom hoist cylinder 1 is diverted to the first main pipe 11 and the connecting pipe 15, and the pressure oil diverted to the connecting pipe 15 flows into the bottom side of the frame hoist cylinder 2 to The undulating cylinder 2 is to be extended. The return oil when the boom hoist cylinder 1 expands and contracts is thus diverted to the main pipelines 11 and 12 and the connection pipelines 15 and 16. As supplied, the connecting line 15 and the first main line 11
Are provided with a variable throttle 8a and a variable throttle 8c, respectively, to adjust the flow rate of the pressure oil diverted to the connection line 15, and
The variable throttle 8b and the variable throttle 8d are provided in the sixth main pipe 12 and the second main pipe 12, respectively, so that the flow rate of the pressure oil diverted to the connection pipe 16 is adjusted. The first main line 11 and the second main line 12 serve as supply / discharge paths for pressure oil on the rod side and the bottom side of the boom hoist cylinder 1 that not only discharges return oil but also supplies pressure oil. In order to supply pressure oil to the rod side and the bottom side,
Each of the variable apertures 8c and 8d is not affected by c and 8d.
A check valve is provided in parallel with d. The same applies to the variable throttles 8a and 8b provided in the connection conduits 15 and 16, respectively.

Reference numeral 17 denotes a pilot main line for guiding the hydraulic pressure of the first main line 11 to a signal receiving portion of the operation check valve 3b.
Reference numeral 18 designates the hydraulic pressure of the second main line 12 as the operating check valve 3.
a, a pilot main pipe leading to the signal receiving portion of a, 15a is a pilot branch pipe that guides the oil pressure of the connection pipe 15 between the operating check valve 3a and the operating check valve 3c to the signal receiving portion of the operate check valve 3d, and 16a is an operating pipe. This is a pilot branch line that guides the oil pressure in the connection line 15 between the check valve 3b and the operation check valve 3d to the signal receiving portion of the operation check valve 3c. The pilot main lines 17 and 18 are provided with electromagnetic pilot operated switching valves 6 and 7 for communicating and shutting off the respective main lines 17 and 18, respectively. As shown in FIG. 2, the pilot main lines 17 and 18 are communicated with each other, and are switched to the left position only when a signal is output to the signal receiving section to shut off the pilot main lines 17 and 18. In this embodiment, the switching of the switching valves 6 and 7 is performed by a signal from a manual operating device such as an operating lever. However, when the switching valves 6 and 7 are not operated, the pilot main lines 17 and 18 are shut off. A sensor for detecting the distance between the boom 21 and the front frame 22 is provided, and the signal from this sensor switches only when the distance is approaching so that the pilot main pipelines 17 and 18 can communicate with each other. It may be. Further, a sensor for detecting the position of each of the boom 21 and the front frame 22 is provided, and the distance between them is calculated by an arithmetic device. A signal is output from the arithmetic device only when the distance is short. Then, the same may be performed.

Next, the operation of the above-described vertical excavator according to this embodiment will be described. When the directional control valve 9 for the boom hoist cylinder is switched from the neutral position to the left position in the figure, the hydraulic oil of the hydraulic pump is supplied to the rod side of the boom hoist cylinder 1 through the first main line 11, and Main line 1
The hydraulic pressure 1 is output as pilot pressure from the pilot main line 17 to the operation check valve 3b via the switching valve 6, and the operation check valve 3b is operated to release the function of the check valve. Then, a part of the return oil on the bottom side of the boom hoist cylinder 1 is diverted to the connection pipe line 16 and supplied to the rod side of the frame hoist cylinder 2 via the operation check valves 3b and 3d. The part is returned to the oil tank via the second main line 12. As a result, the boom raising / lowering cylinder 1 is contracted to operate the boom 21 in the downward direction. During this time, the pressure oil diverted to the connection pipe line 16 is output as pilot pressure to the operating check valve 3c through the pilot branch pipe line 16a, and is output to the operation check valve 3c.
In order to operate c, the pressure oil on the bottom side of the frame up-and-down cylinder 2 is returned from the connection pipe 15 to the rod side of the boom up-and-down cylinder 1 via the operation check valves 3c and 3a. As a result, the frame up / down cylinder 2 is reduced in conjunction with the reduction of the boom up / down cylinder 1, and the front frame 22 is moved in the down direction. In that case, as described above, by providing the variable throttle 8b and the variable throttle 8d in the connection pipeline 16 and the second main pipeline 12, respectively, and adjusting the flow rate of the pressure oil diverted to the connection pipeline 16, The frame up-and-down cylinder 2 is reduced so that the front frame 22 does not hit the boom 21, so that the two do not interfere with each other.

When the directional control valve 9 for the boom hoist cylinder is switched from the neutral position to the right position in the state where the boom hoist cylinder 1 and the frame hoist cylinder 2 are reduced in this manner, the hydraulic oil of the hydraulic pump is supplied to the second main line. The hydraulic pressure of the second main line 12 is supplied as a pilot pressure from the pilot main line 18 to the operation check valve 3a via the switching valve 7 through the switching valve 7, and is supplied to the bottom side of the boom hoist cylinder 1 through the operation check valve 3. 3a
Operates. Then, a part of the return oil on the rod side of the boom hoist cylinder 1 is diverted to the connection pipe 15 and supplied to the bottom side of the frame hoist cylinder 2 via the operation check valves 3a and 3c. The part is returned to the oil tank via the first main line 11. As a result, the boom raising / lowering cylinder 1 is operated in a direction in which the boom 21 is extended and raised. During this time, the pressure oil diverted to the connection line 15
The pilot pressure is output as pilot pressure to the operation check valve 3d through the pilot branch line 15a, and in order to operate the valve 3d, pressure oil on the rod side of the frame up-and-down cylinder 2 is transmitted from the connection line 16 via the operation check valves 3d and 3b. It is returned to the bottom side of the boom hoist cylinder 1.
As a result, the frame up / down cylinder 2 extends in conjunction with the extension of the boom up / down cylinder 1 and the front frame 22
In the direction that causes In this case, as described above, the connection pipe 15 and the first main pipe 12 are provided with the variable throttle 8a and the variable throttle 8c, respectively, so that the flow rate of the pressure oil diverted to the connection pipe 15 is adjusted. The frame up-and-down cylinder 2 has a front frame 22 with a boom 2
They extend so as not to hit 1 so that they do not interfere with each other.

In this embodiment, as is apparent from FIG. 2, the boom 21 is not linked to the front frame 22 when the front frame 22 is raised and lowered. This is because if the boom 21 is raised and lowered during operation of the front frame 22 during suspension, the suspended load suddenly starts moving, which is dangerous. The operation by the boom 21 involves a lot of danger and is a difficult operation, whereas the operation by the front frame 2 is difficult.
Since the operation 2 itself does not involve much danger and is not a difficult operation, the operation can be smoothly performed without providing a special interference prevention mechanism. Even if the front frame 22 comes into contact with the boom 21, no serious problem occurs even if the front frame 22 is suddenly stopped by operating the conventional automatic stop mechanism of the front frame 22 normally provided. However, the present invention does not prevent the boom 21 from being linked to the front frame 22.

The relationship between the operation of the boom hoist cylinder 1 and the frame hoist cylinder 2 described above and the operation of the boom 21 and the front frame 22 is summarized and shown in a table.
As shown in FIG. “Up” and “down” in the columns of the boom hoist cylinders and the frame hoist cylinders mean raising and lowering operations of the boom hoist cylinders 1 and the frame hoist cylinders 2, that is, extending and reducing operations of these cylinders 1 and 2. . The “raised” and “raised” in the columns of the boom undulation and the frame undulation are the boom 21 and the front frame 2.
2 means the movement in the down direction and the movement in the rising direction.
The “indirect operation” in the note below the table in FIG. 2 means that the boom hoist cylinder 1 and the frame hoist cylinder 2 operate in conjunction with one of the operations.

As described above, according to this embodiment, when the boom hoist cylinder 1 is reduced, the pressure oil on the bottom side of the boom hoist cylinder 1 flows into the rod side of the frame hoist cylinder 2 through the connection pipe 16. At the same time, the pressurized oil on the bottom side of the frame up / down cylinder 2 is discharged through the connection pipe 15, whereby the front frame 22 is moved in conjunction with the reduction of the boom up / down cylinder 1.
1 so that the cylinder 2 can be reduced so as not to hit the boom 21 and the front frame 2.
The interference between the boom 21 and the front frame 22 can be prevented when the boom hoist cylinder 1 that is likely to interfere with the boom 2 is reduced. In addition, when performing various operations with a vertical excavator, it is sufficient to simply operate the boom hoist cylinder 1 and the frame hoist cylinder 2, and handle and connect and disconnect two types of ropes as in a conventional vertical excavator. Since there is no need to perform such operations, a vertical excavator with good workability and safety can be obtained. By the way, when excavating a pit, a load is generated due to an excavation reaction force such as a pushing-up force. In the present embodiment, the frame up-and-down cylinder 2 is installed on the self-propelled vehicle body 20 as a base machine. Therefore, the load is not received only by the weight of the front frame 22 and the keriba 23 as in the conventional vertical excavator, but is transmitted through the frame up-and-down cylinder 2 to the main body 20 of the self-propelled vehicle.
And the total weight of the pit excavator including the weight of the boom 21 and the like. As a result, a load caused by an excavation reaction force such as a pushing force can be sufficiently supported, and a change in the attitude of the front frame 22 due to the load can be prevented, so that accurate excavation can be performed. Further, in the conventional vertical excavator, a vertical downward load acts on the front frame 22 by its own weight or the like, and the load is applied to the boom 21 via the frame hoisting rope 22 a and the hydraulic cylinder 26.
However, in the vertical excavator of this embodiment, since both the front frame 22 and the frame undulating cylinder 2 are installed in the self-propelled vehicle body 20, unlike the conventional vertical excavator, Such a load is not transmitted to the boom 21, and there is no need to reinforce the boom 21.

In this embodiment, when the boom hoist cylinder 1 is contracted, the connecting pipe 15 and the connecting pipe 16 are respectively connected to the pressure oil discharge path on the bottom side of the frame hoist cylinder 2 and the bottom of the boom hoist cylinder 1. Not only is used for the inflow path of the hydraulic oil on the side, but also when the boom hoist cylinder 1 is extended, the inflow path through which the rod-side hydraulic oil of the boom hoist cylinder 1 flows into the bottom side of the frame hoist cylinder 2 and It is also used as a discharge path for discharging pressure oil on the rod side of the frame up / down cylinder 2, so that the front frame 22 does not hit the boom 21, and the frame up / down cylinder is linked with the extension of the boom up / down cylinder 1. 2 is appropriately extended. As a result, when the boom 21 is raised as well as when the boom 21 is lowered, the front frame 22 can be automatically moved so as not to hit the boom 21 by operating the boom lifting cylinder 1 alone. The operation of the frame 22 can be performed more easily. In this case, the connection pipe 15 and the connection pipe 16 are effectively used in combination with both the pressure oil inflow path of the boom hoist cylinder 1 and the pressure oil discharge path of the frame hoist cylinder 2. The hydraulic circuit is simplified while the effect is added. In this embodiment, variable throttle valves 8a and 8c for adjusting the flow rate are provided in the connection pipe 15 and the first main pipe 11, respectively, so that the hydraulic oil diverted to the connection pipe 15 when the boom hoist cylinder 1 is extended. And the variable throttle valves 8b and 8d for adjusting the flow rate are provided in the connection pipe line 16 and the second main pipe line 12, respectively. Since the flow rate of the divided pressure oil is adjusted, when the frame up-and-down cylinder 2 is extended and contracted in conjunction with the boom up-and-down cylinder 1, the front frame 22 can be extended and contracted while maintaining an appropriate positional relationship with the boom 21. become.

In this embodiment, the operation check valves 3a and 3c are provided in the connection line 15 and the operation check valves 3b and 3d are provided in the connection line 16, so that the boom 2 is provided.
After setting the position of the front frame 1 and the front frame 22,
The operating check valve 3a and the operating check valve 3c can block the pressure oil on the rod side of the boom hoist cylinder 1 and the bottom side of the frame hoist cylinder 2 from flowing out through the connection line 15, respectively. The operation of the operating check valve 3b and the operating check valve 3d, respectively, indicates that the pressure oil on the bottom side and the rod side of the frame up-and-down cylinder 2 flows out through the connection pipe line 16.
Can be shut off. As a result, the boom 21 and the front frame 22 can be reliably held in the set posture, and the front and lower cylinders 2 can be independently operated to independently raise and lower only the front frame 22. In this embodiment, the pilot main lines 17, 18 for operating the operation check valves 3b, 3a are
Since the switching valves 6 and 7 for communicating and shutting off the respective pilot lines 17 and 18 are provided, the switching valves 6 and 7 are switched to the left position to shut off the pilot lines 17 and 18 so that the frame is cut off. The up-and-down cylinder 2 can also be released from expanding and contracting in conjunction with the expansion and contraction of the boom up-and-down cylinder 1. Therefore, for example, when the boom 21 and the front frame 22 are separated from each other and there is no possibility of interference, or when the operator is skilled in manual operation and does not want to link the front frame 22 to the boom 21. Only needs to switch the switching valves 6 and 7 to the left position.
Can be selectively performed as needed.

In this embodiment, the operating check valves 3a, 3c and the operating check valves 3b, 3d are provided in the connecting pipe 15 and the connecting pipe 16, respectively. However, these operating check valves 3a, 3c, 3b, 3d are provided. Is a switching means for connecting the connecting pipes 15 and 16 to allow the pressurized oil to flow between the boom hoist cylinder 1 and the frame hoist cylinder 2 when the boom hoist cylinder 1 is expanded and contracted. Other switching means, such as providing an on-off valve for opening and closing the connection pipelines 15 and 16 in conjunction with the operation of the undulating cylinder 1, may be used. In the present embodiment, the switching valves 6 and 7 are provided in the pilot main lines 17 and 18. However, the switching valves 6 and 7 may not be provided when it is desired that the front frame 22 is always linked with the boom 21. can do.

[0028]

As is apparent from the above description, the present invention comprises a boom mounted on a base machine so as to be able to be raised and lowered, and a front frame which is supported on the base machine so as to be able to be raised and lowered and on which a keriba rotary driving device is mounted. In a vertical excavator in which a pit is excavated by a pit excavating means by lowering a kelly bar while rotating it with a kelly bar rotary driving device, a "boom raising / lowering cylinder for raising / lowering a boom and a frame for raising / lowering a front frame" Each of the up-and-down cylinders is installed on the base machine, and a connection pipe for connecting the bottom side of the boom-up / down cylinder and the rod side of the frame up-and-down cylinder, and a discharge pipe for discharging pressure oil at the bottom of the frame up-and-down cylinder are provided. When the boom is lowered and the boom is lowered, the boom is lifted by connecting the connecting pipe. The pressure oil on the bottom side of the cylinder is caused to flow into the rod side of the frame up-and-down cylinder, and the discharge oil passage is connected to discharge the pressure oil on the bottom side of the frame up-and-down cylinder. In conjunction with the reduction, the frame up / down cylinder is reduced so that the front frame does not hit the boom. '' The vertical excavator obtained by the present invention can prevent interference between the boom and the front frame, and Good workability and safety. In addition, since both the frame up / down cylinder and the front frame are installed in the base machine, the load caused by the excavation reaction force such as the pushing-up force during excavation can be reduced by the total weight of the pit excavator via the frame up / down cylinder. In addition to being able to carry out accurate excavation by receiving enough, even if a vertical downward load acts on the front frame due to its own weight, the load is not transmitted to the boom, There is no need to reinforce.

When the present invention is embodied, if the technical means described in claims 2 to 6 are adopted, the following effects can be obtained in addition to the above effects. be able to. That is, when the present invention is embodied, if the technical means described in claim 2 is adopted, when the frame up-and-down cylinder is reduced in conjunction with the boom up-and-down cylinder, the front frame and the boom are appropriately It is possible to reduce the size while maintaining the positional relationship. When the present invention is embodied, if the technical means described in claim 3 is adopted, not only when the boom is lowered but also when the boom is raised, the front frame can be operated by operating the boom lifting cylinder independently. Can be automatically moved so as not to hit the boom, and the operation of the front frame can be performed more easily. Further, the hydraulic circuit is simplified while adding such excellent effects. In the case of embodying the present invention, if the technical means described in claim 4 is adopted, the vertical excavator described in claim 3 also adopts the technical means described in claim 2. It has the same effect as in the case. When the present invention is embodied, if the technical means described in claim 5 is adopted, the boom and the front frame can be reliably held in the set posture, and the frame up / down cylinder can be used. By operating alone, only the front frame can be raised and lowered independently. When embodying the present invention,
If the technical means described in claim 6 is adopted, the automatic operation of the front frame in conjunction with the boom can be selectively performed as needed.

[Brief description of the drawings]

FIG. 1 is a side view schematically showing an overall image of a pit excavator according to an embodiment of the present invention.

FIG. 2 is a hydraulic circuit diagram of a vertical excavator according to an embodiment of the present invention.

FIG. 3 is an operation chart of a vertical excavator according to an embodiment of the present invention.

FIG. 4 is a side view showing an overall image of a pit excavator according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Boom raising / lowering cylinder 2 Frame raising / lowering cylinder 3a-3d Operate check valve 4,5 Counter balance valve 6,7 Switching valve 8a-8d Variable throttle 9 Direction switching valve for boom lifting cylinder 10 Direction switching valve for frame lifting cylinder 10-10 14 Main Pipeline 15, 16 Connection Pipeline 15a, 15b Pilot Support Pipeline 17, 18 Pilot Main Pipeline 20 Self-Propelled Car Body 21 Boom 22 Front Frame 23 Kelly Bar 24 Excavation Bucket 25 Kelly Bar Rotary Drive

Claims (6)

[Claims] 1. A boom mounted on a base machine so as to be able to raise and lower, and a front frame mounted on a base machine so as to be able to be raised and lowered and mounted with a kerry bar rotation driving device, and the kerry bar is lowered while being rotationally driven by the kerry bar rotation drive device. In a pit excavator which excavates a pit by means of a pit excavation means, a boom raising / lowering cylinder for raising / lowering a boom and a frame raising / lowering cylinder for raising / lowering a front frame are respectively installed in a base machine, and the bottom of the boom raising / lowering cylinder is provided. When the boom hoisting cylinder is operated in a direction in which the boom is lowered by providing a connecting pipe connecting the side and the rod side of the frame hoisting cylinder, and a discharge pipe for discharging pressure oil on the bottom side of the frame hoisting cylinder. Through the connection pipe, and pressurized oil on the bottom side of the boom In addition, the pressure oil flows into the rod side of the cylinder and communicates with the discharge pipe to discharge the hydraulic oil on the bottom side of the frame up-and-down cylinder. A vertical excavator, characterized in that the frame up-and-down cylinder is reduced so as not to hit the pit. 2. A valve for adjusting a flow rate is provided in each of a connecting pipe connecting the bottom side of the boom hoist cylinder and the rod side of the frame hoist cylinder and a main pipe on the bottom side of the boom hoist cylinder. 3. The pit excavator according to claim 1, wherein the flow rate of the pressure oil diverted to the connection pipe when the cylinder is reduced is adjusted. 3. A discharge pipe for discharging pressure oil on the bottom side of the frame up-and-down cylinder with a connecting pipe connecting the rod side of the boom up-and-down cylinder and the bottom side of the frame up-and-down cylinder. When operating in the direction in which the boom is raised by extension, the connecting pipe is connected to allow the pressure oil on the rod side of the boom lifting cylinder to flow into the bottom side of the frame lifting cylinder and the bottom side of the boom lifting cylinder. And a connecting line connecting the rod side of the frame up-and-down cylinder to discharge pressure oil on the rod side of the frame up-and-down cylinder,
2. The pit excavator according to claim 1, wherein, in conjunction with the extension of the boom hoist cylinder, the frame hoist cylinder is extended so that the front frame does not hit the boom. 4. A valve for adjusting a flow rate is provided on each of a connecting pipe connecting the bottom side of the boom hoist cylinder and the rod side of the frame hoist cylinder and a main pipe on the bottom side of the boom hoist cylinder. Along with adjusting the flow rate of the pressure oil diverted to the connection pipe when the cylinder is reduced, the connection pipe connecting the rod side of the boom hoist cylinder and the bottom side of the frame hoist cylinder,
4. The valve according to claim 3, wherein a valve for adjusting the flow rate is provided to adjust the flow rate of the pressure oil diverted to the connecting pipe when the boom hoist cylinder is extended.
Pit excavator. 5. A first operation check valve for flowing a pressurized oil only to a bottom side of a boom-up-and-down cylinder in a connection pipe connecting a bottom side of the boom-up-and-down cylinder and a rod side of a frame-up-and-down cylinder when not in operation. Secondly, pressurized oil flows only toward the rod side of the frame up / down cylinder when not operating
Operating check valves are provided on the bottom side of the boom hoisting cylinder and the rod side of the frame hoisting cylinder, respectively, and in the connecting pipe connecting the rod side of the boom hoisting cylinder and the bottom side of the frame hoisting cylinder, A third operated check valve for flowing pressure oil only in the direction of the cylinder rod and a fourth operation check valve for flowing pressure oil only in the direction of the bottom of the frame raising / lowering cylinder when not in operation are provided on the rod side of the boom raising / lowering cylinder and the frame, respectively. Installed on the bottom side of the undulating cylinder,
When the boom hoist cylinder is contracted, the first and fourth operate check valves are operated to release the check valve function, and when the boom hoist cylinder is extended, the second operate check valve and the third operate check valve are operated. The pit excavator according to claim 3 or 4, wherein the function of the check valve is released by operating the operation check valve. 6. The first check valve, the second check valve, the third check valve, and the fourth check valve are operated check valves operated by a hydraulic pilot, and these check valves are operated. 6. The excavator according to claim 5, wherein a switching valve for communicating and shutting off the hydraulic pilot line is provided in the hydraulic pilot line.