JPH06313394A - Detecting method for excavated diameter by underwater excavator vertical and equipment thereof - Google Patents

Abstract

PURPOSE:To enhance working accuracy by measuring the quantity of a working pressured liq. sent to a hydraulic cylinder for oscillation by means of an excavated diameter detector and by calculating the moving degree of the cylinder based on a change in the quantity of pressured liq. by means of a computer to detect excavated diameter. CONSTITUTION:Driving a hydraulic pump feeds an operating pressured liq. in a first synchronous cylinder 37a through a hose 36 to move a piston, actuating a second synchronous cylinder 37b. The pressured liq. passes through the hose 36 from the cylinder 37b and enters a hydraulic cylinder 9 for oscillation at its (A) side port through the pressured liq. passage 39a of a rotating coupler part 38 in excavator body 2 and returns to a tank through a hose 40. The pressured liq. passes through a pressured liq. passage 39b from the cylinder 9 at its B side port and returns to the cylinder 37b through the hose 40. A variation in flow rate is converted into an electric signal by means of a converter corresponding to the quantity of detection from the excavated diameter detector 16 of the cylinder 37b and is sent to a control device. In addition, a computer in the control unit calculates the moving degree of the cylinder 9 to display the calculated value on an excavated diameter display panel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting, displaying, and controlling a diameter of an underwater excavator for a vertical hole used for a vertical hole excavation work when a foundation of a bridge or a jetty is constructed on the seabed or the waterbed.

[0002]

2. Description of the Related Art Conventionally, when constructing a foundation for a bridge or jetty on the seabed or waterbed, a steel pipe pile (casing pipe) is driven into a relatively soft stratum with a hydraulic hammer or the like to form a relatively hard rock layer at the tip of the steel pipe pile. After reaching, the steel pipe pile is excavated and the relatively hard bedrock layer under the steel pipe pile is also excavated, and concrete is poured into the pit to consolidate the steel pipe pile and the rock mass. There is. As a pit excavator for excavating the pit, an earth auger, a pit underwater excavator, or the like is used. In general, an underwater excavator for pits performs excavation work at the bottom of piles on the sea floor, but the operation was performed by remote control on a pier on the sea.

In order to perform the above remote control, the excavation diameter,
It is necessary to detect the amount of expansion and contraction of the rocking arm and the turning angle (turning position) of the turning support member. Among them, accurate detection of the excavation diameter is necessary in the excavation work on the pile bottom of the seabed by the underwater excavator for vertical holes. This is a mandatory condition. Therefore, when it becomes impossible to accurately detect the diameter of the excavation, the excavation work may have to be interrupted.

As disclosed in Japanese Utility Model Publication No. 4-17661, a conventional underwater excavator for a vertical hole has a supporting frame suspended in a steel pipe pile and a turning drive fixed to the supporting frame. A swivel support member swiveled by the swivel drive device is attached to the lower part of the excavator main body including a device, and the upper end of the swing arm having the swing hydraulic cylinder built in is attached to the swivel support member by a horizontal axis. In a vertical hole underwater excavator in which a drum cutter rotated by a drive device is attached to the lower part of the swing arm, the excavation diameter is changed by swinging the swing arm by expanding and contracting the swing hydraulic cylinder. It is designed to be used.

In the above-mentioned conventional underwater excavator for vertical holes, a steel pipe pile 1 is supported by a leader of a pile driving ship as shown in FIG. It is hung down to the seabed by a rope. The underwater excavator K for pit has two upper and lower grippers 3 and 4 for detachably fixing the excavator body 2 to the inner wall of the steel pipe pile 1, and the excavator body 2 has its inner cylinder. A hydraulic motor and a speed reducer for turning are provided for driving the turning of the gear 5, and an output gear of the turning speed reducer meshes with a gear fixed to the upper part of the inner cylinder 5. On the other hand, a swivel support member 6 is attached to the lower end of the inner cylinder 5, and the swivel arm 8 equipped with an excavating portion 7 such as a drum cutter is attached to the swivel support member 6.
The upper end of the rocking arm 8 is pivotally attached by a horizontal shaft 8a.
A hydraulic cylinder 9 for swinging an arm is mounted between the swivel support member 6 and the swivel support member 6 so that the swing arm 8 can be swung with respect to the swivel support member 6 together with the excavation unit 7. Reference numeral 10 is a suction hose.

In the above-mentioned conventional underwater excavator K for pit detection, the excavation diameter is detected by determining the swing angle of the swing arm 8 which swings together with the swing support member 6 as shown in FIGS. Via lever 12 and link 13 attached to
A linear movement amount is converted by a striker 15 supported by a striker guide 14 provided on the swivel support member 6, and the movement amount is changed by a roller 18 at a tip of a rod 17 of an excavation diameter detector 16 of the striker 15 sliding surface 19. When rolling on the slope, the rod 17 is pushed up into the excavation diameter detector 16 against the biasing force of the spring 20. At that time, the rod 17
The rack 21 which is integrated with is attached to the shaft 23 of the converter 22 according to the amount of movement thereof, and rotates the pinion 24, and at the same time, rotates the shaft 23 of the converter 22. This rotation amount is converted into an electric signal and sent to the control device on the sea by the cable 25, and displayed as an excavation diameter on the instrument on the operation desk.

[0007]

However, in the above-mentioned conventional excavation diameter detecting device, the swing support in which the devices 15 and 19 for converting the swing angle of the swing arm into a linear movement amount are constantly swinging during excavation work. Since the excavation diameter detector 16 is attached to the side of the member 6 and the excavation diameter detector 16 is attached to the fixed support frame side, the striker 15 and the rod 17 can detect the excavation diameter only at one point where they are in the same turning position. There was a drawback that I could not. Moreover, since the excavation diameter can be detected only at one point, there is a serious drawback that the excavation diameter cannot be changed at any position during excavation.

In addition, normally, the scraps scraped off by the excavating portion 7 such as a drum cutter at the pile bottom P are suction hoses 1.
Since it is sucked in by 0 and discharged to the sediment carrier on the sea, the gap does not float around the excavation diameter detector 16 on the pile bottom P. However, when the suction hose is clogged, if the excavation work is continued without noticing the failure, the gap is filled in the vicinity of the pile bottom P and the periphery of the excavation diameter detector 16 also has a gap. In such a case, as a result, a gap is caught between the roller 18 at the tip of the rod 17 and the striker sliding surface 19. In addition, there is a risk that the rod will be bent or broken and it will be impossible to detect the excavation diameter.

The present invention has been made in view of the above circumstances, and is provided at any position during excavation of a rocking arm equipped with an excavating portion such as a drum cutter, and is not affected by a bite of a slip or the like. It is an object of the present invention to provide a method and a device for detecting an excavation diameter of an underwater excavator for a vertical hole, which can accurately detect the excavation diameter.

[0010]

In order to achieve the above object, the present invention is formed in the lower part of a swivel inner cylinder in a body of an underwater excavator for pits suspended from above water through a steel pipe pile. In the method for detecting the excavation diameter of an underwater excavator for a vertical shaft, in which the excavation part is swingably provided with respect to the excavator body by a swingable arm provided on a swivel support member, the swing arm is driven. The excavation diameter detector provided in the second synchronous cylinder measures the amount of the working pressure liquid sent to the oscillation hydraulic cylinder for changing the excavation diameter by swinging the excavation portion, and the change in the amount of the hydraulic fluid is measured. The excavation diameter is detected by calculating the moving amount of the rocking hydraulic cylinder using a computer using the electric signal, and the amount and flow direction of the working pressure liquid sent to the rocking hydraulic cylinder are detected. Controlled by the first synchronous cylinder The excavation is swung out diameter detection drilling vertical holes underwater excavator characterized by changing the drilling diameter is controlled method.

Further, excavation is performed by a swing arm provided swingably on a swivel support member formed below a swivel inner cylinder in a main body of an underwater excavator for a vertical hole suspended through water through a steel pipe pile. In the excavation diameter detection display control device of the underwater excavator for pits, which is swingably provided with respect to the excavator body,
An oscillating hydraulic cylinder that changes the rotary excavation diameter of the excavating portion is provided between the swivel support member and the oscillating arm, and the working hydraulic fluid to the oscillating hydraulic cylinder is sent by the second synchronous cylinder, The change in the amount of pressure fluid measured by the excavation diameter detector provided in the synchronous cylinder 2 is converted into an electric signal, and the movement amount of the rocking hydraulic cylinder is calculated using a computer by the electric signal, and the excavation diameter is calculated. An operating device for controlling the amount and the flow direction of the working pressure liquid sent to the rocking hydraulic cylinder is provided while displaying it on the drilling diameter display panel,
The operation device operates the first synchronous cylinder to control the amount and flow direction of the working pressure liquid sent to the rocking hydraulic cylinder to rock the excavating portion to change the excavating diameter. Is a display control device for detecting and displaying an excavation diameter of an underwater excavator for a pit.

[0012]

Next, the operation of the excavation diameter detecting device for a submersible excavator for a pit according to the present invention will be described. Pressure fluid is discharged from a hydraulic pump constantly driven by an electric motor, and a swing hydraulic cylinder. If the electromagnetic directional control valve is kept in a state as shown in FIG. 2 when is not operated, the pressurized liquid is returned to the tank as it is. Then, first, when increasing the excavation diameter during turning excavation, one solenoid of the electromagnetic directional control valve is energized and excited to switch the port of the electromagnetic directional control valve to the state shown in FIG. Operation pressure liquid is first
When the piston is moved to the synchronous cylinder, the second synchronous cylinder is actuated via the connecting rod, and the operating pressure liquid is sent to the A side port of the rocking hydraulic cylinder through the rotary joint of the excavator body. Then, the rocking hydraulic cylinder is extended to increase the angle of the rocking arm to increase the excavation diameter.

On the contrary, when the excavation diameter during the swivel excavation is reduced, the other solenoid of the electromagnetic directional control valve is energized and excited to switch the port of the electromagnetic directional control valve, and the hydraulic pump is operated. When the operating pressure liquid is sent to the first synchronous cylinder, the piston moves, the second synchronous cylinder operates via the connecting rod, and the operating hydraulic liquid passes through the rotary joint of the excavator body to the B side of the hydraulic cylinder. It is sent to the port and the rocking hydraulic cylinder is contracted to reduce the angle of the rocking arm and the excavation diameter can be reduced.

At this time, the amount of working pressure liquid moving in the second synchronizing cylinder is proportional to the expansion and contraction amount of the swinging hydraulic cylinder, and the amount of working pressure liquid moving in the second synchronizing cylinder is proportional. The expansion / contraction amount of the rocking hydraulic cylinder can be calculated by measuring That is, the excavation diameter with respect to the expansion / contraction amount of the rocking hydraulic cylinder can be measured, and if this numerical value is input as data to the computer in the control device, the excavation diameter and the operating pressure moving in the second synchronous cylinder can be measured. Since a proportional relationship is established with the amount of liquid, it is possible to detect the excavation diameter by measuring the amount of working pressure liquid sent to the rocking hydraulic cylinder and calculating the amount of movement of the rocking hydraulic cylinder. .

Therefore, the change in the working fluid pressure measured by the excavation diameter detector provided in the second synchronous cylinder is converted into an electric signal, and the electric signal causes the computer to swing the swing hydraulic cylinder. Let me calculate the amount of movement,
The excavation diameter currently being excavated is displayed on the excavation diameter display panel, and the first synchronous cylinder is operated by the operating device which controls the amount and the flow direction of the working hydraulic fluid sent to the rocking hydraulic cylinder by the displayed numerical value. It is also possible to control the amount and the flow direction of the operating pressure liquid sent to the rocking hydraulic cylinder by the second synchronizing cylinder, and rock the excavation part during excavation to change the excavation diameter.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for detecting an excavation diameter of an underwater excavator for pits and an apparatus therefor according to the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional explanatory view of an essential part of this embodiment, and FIG. 2 shows a hydraulic control circuit diagram and an electric signal circuit diagram. In the figure, the same or equivalent parts as those in the conventional example are designated by the same reference numerals, and detailed description thereof will be omitted.

In the underwater excavator K for pits of this embodiment shown in FIG. 1, the steel pipe pile 1 is supported by a leader of a pile driving ship, like the conventional underwater excavator for pits. The underwater excavator K for pits is hung by a wire rope to the seabed. The underwater excavator K for a vertical hole is a top and bottom 2 for detachably fixing the excavator body 2 to the inner wall of the steel pipe pile 1.
The excavator main body 2 is provided with two grippers 3 and 4, and a hydraulic motor for driving the inner cylinder 5 of the excavator and a speed reducer for turning are disposed, and an output gear of the speed reducer for turning is provided. Engages with a gear fixedly provided on the upper portion of the inner cylinder 5. On the other hand, a swivel support member 6 is attached to the lower end of the rotating inner cylinder 5, and the swivel support member 6 is provided with an upper end of a swing arm 8 equipped with an excavation unit 7 such as a drum cutter. 8a is pivotally mounted, and an arm rocking hydraulic cylinder 9 is mounted between the rocking arm 8 and the swivel support member 6 to rock the rocker arm 8 together with the excavation unit 7 with respect to the swivel support member 6. It is configured to be movable.

As shown in FIG. 1, the excavation diameter detecting device for the underwater excavator for vertical holes according to the present embodiment rotates the excavation portion 7 such as a drum cutter between the swivel support member 6 and the swing arm 8. A rocking hydraulic cylinder 9 for changing the excavation diameter is provided, and the working hydraulic fluid sent to the rocking hydraulic cylinder 9 is as shown in FIG. First, the electric motor 3 of the operating device 34 including the electric motor 31, the hydraulic pump 32, and the electromagnetic directional control valve 33.
The operating pressure liquid is discharged from the hydraulic pump 32 that is constantly driven by 1. If the rocking hydraulic cylinder 9 is not operated, the electromagnetic directional control valve should be in the state shown in FIG. For example, the pressurized liquid is returned to the tank 35 as it is and circulated.

When the working hydraulic fluid is sent to the swinging hydraulic cylinder 9, the electromagnetic directional control valve 33 of the operating device 34 is energized by energizing the solenoid on the side a to excite the electromagnetic directional control valve 33.
When the ports of the hydraulic pump are switched to the state of FIG. 3, the operating pressure liquid from the hydraulic pump is transferred to the first synchronous cylinder 3 by the hose 36.
7a, the piston is moved to the right, and the second synchronizing cylinder 37b is operated via the connecting rod 43.
Since the second synchronizing cylinder 37b and the swinging hydraulic cylinder 9 are filled with the pressurized liquid via the two hoses 36 and 40, respectively, the second synchronizing cylinder 37
The working hydraulic fluid from b passes through the hose 36 and the hydraulic fluid passage 39a provided in the rotary joint portion 38 of the excavator main body 2 and is sent to the A-side port of the swing hydraulic cylinder 9.

On the other hand, B on the opposite side of the swing hydraulic cylinder 9
The working pressure liquid from the side port returns to the second synchronizing cylinder 37b by the hose 40 through the pressure liquid passage 39b provided in the rotary joint portion 38. In addition, the first synchronizing cylinder 3
The operating pressure liquid from 7a is returned to the tank 35 by the hose 40 through the electromagnetic directional control valve 33.

The converter 22 converts the change in the flow rate into an electric signal according to the detection amount of the excavation diameter detector 16 provided in the second synchronous cylinder 37b, and the electric signal is set in the control device 41. The computer operates to calculate the movement amount of the swing hydraulic cylinder 9, and the calculated value is displayed on the excavation diameter display panel 42. At this time, if the cross-sectional areas of the swing hydraulic cylinder 9 and the second synchronizing cylinder 37b are the same, the amount of working hydraulic fluid moving in the second synchronizing cylinder 37b and the expansion and contraction of the swing hydraulic cylinder 9 are increased. The expansion / contraction amount of the rocking hydraulic cylinder can be calculated by measuring the amount of the working pressure liquid moving in the second synchronizing cylinder 37b in proportion to the amount.

That is, the excavation diameter with respect to the expansion and contraction amount of the rocking hydraulic cylinder can be measured, and this value is used as the control device 4.
If it is input as data to the computer in 1, the relationship of D∝Q is established. Here, D: excavation diameter (mm), Q: amount (cc) of working hydraulic fluid moving in the second synchronous cylinder 37b. Then, by measuring the amount of the working pressure liquid sent to the rocking hydraulic cylinder 9, the moving amount of the rocking hydraulic cylinder 9 can be calculated by the computer in the control device 41 to calculate the excavation diameter. Further, based on the current numerical value displayed on the excavation diameter display panel 42, the amount and the flow direction of the working pressure liquid sent to the rocking hydraulic cylinder 9 are operated by the operation device 34 to the first synchronizing cylinder 37a. By sending the pressurized liquid, the second synchronous cylinder 37b is operated, and the swing arm 8 provided with the excavating portion 7 which is driven to swing is swung to accurately change the excavation diameter.

In the present embodiment, when the excavation diameter of the excavating portion 7 such as the drum cutter being swiveled is increased based on the numerical value displayed on the excavation diameter display panel 42, the electromagnetic directional control valve 33 is used. The solenoid on the side a is energized and excited to switch the port of the electromagnetic directional control valve 33 to the state shown in FIG. 3, and the operating pressure liquid from the hydraulic pump 32 is transferred to the first position by the hose 36. When sent to the synchronous cylinder 37a of No. 1, the piston moves to the right, the second synchronous cylinder 37b is actuated via the connecting rod 43, and the working pressure liquid is supplied from the hose 36 of the second synchronous cylinder 37b to the excavator. It is sent to the A side port of the rocking hydraulic cylinder 9 through the rotary joint portion 38 of the main body 2, and is fed to the rocking hydraulic cylinder 9
To increase the angle of the swing arm 8 to increase the excavation diameter.

On the contrary, when the excavation diameter of the excavating portion 7 such as the drum cutter being swiveled is reduced, the solenoid on the side b of the electromagnetic directional control valve 33 is energized to excite the electromagnetic directional control. When the port of the valve 33 is switched and the operating pressure liquid from the hydraulic pump 32 is sent to the first synchronizing cylinder 37a through the hose 40, the piston moves to the left, and the second synchronizing member moves through the connecting rod 43. Cylinder 37
When b is actuated, the working hydraulic fluid is sent to the B side port of the hydraulic cylinder through the rotary joint 6 of the excavator main body 2, and the rocking hydraulic cylinder 9 is contracted to reduce the rocking arm angle to reduce the excavation diameter. Can be made smaller.

[0025]

According to the present invention described above, the amount of the working pressure liquid sent to the rocking hydraulic cylinder for driving the rocking arm to rock the excavating portion to change the excavating diameter is set to the second amount. The excavation diameter is measured by the excavation diameter detector provided in the synchronous cylinder, and the change in the amount of pressure fluid is converted into an electric signal, and the excavation diameter is detected by using the computer to calculate the movement amount of the rocking hydraulic cylinder. At the same time, it is possible to always accurately know the diameter of the excavation during the swivel excavation on the seabed, and at the same time, it is possible to control the amount and the flow direction of the working hydraulic fluid sent to the rocking hydraulic cylinder by the second synchronous cylinder, whereby the Since the excavation part can be continuously swung, the excavation diameter can be freely changed at any position during the swivel excavation, and the excavation work on the pile bottom driven into the sea bottom can be accurately performed.

Further, the change in the working fluid pressure measured by the excavation diameter detector provided in the second synchronizing cylinder which operates in synchronization with the rocking hydraulic cylinder is converted into an electric signal, and the electric signal causes the computer to operate. Since the amount of movement of the rocking hydraulic cylinder is accurately calculated using, the drilling diameter during turning excavation can always be accurately displayed on the drilling diameter display panel, and the rocking hydraulic pressure can be displayed based on the displayed numerical value. As for the control of the amount and the flow direction of the working pressure liquid sent to the cylinder, the operating device operates the first synchronizing cylinder to continuously control the second synchronizing cylinder. It is possible to accurately form the diameter of the drill hole in the excavation performed on the driven pile bottom.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view of a main part of this embodiment.

FIG. 2 is a circuit explanatory diagram of a control device and an operating device.

FIG. 3 is a circuit diagram of an electromagnetic directional control valve.

FIG. 4 is a side view of a conventional example.

FIG. 5 is a cross-sectional explanatory view of a conventional excavation diameter detecting device.

FIG. 6 is an explanatory diagram of a converter used in a conventional excavation diameter detecting device.

[Explanation of symbols]

 1 Steel Pipe Pile 2 Excavator Main Body 5 Inner Cylinder 6 Swiveling Support Member 7 Excavator 8 Swing Arm 8a Horizontal Axis 9 Hydraulic Cylinder for Swing 10 Suction Hose 31 Electric Motor 32 Hydraulic Pump 33 Electromagnetic Directional Change Valve 34 Operating Device 35 Tank 36 Pressure Liquid Hose 37a First Synchronous Cylinder 37b Second Synchronous Cylinder 38 Rotating Joint 39a Pressure Liquid Passage 39b Pressure Liquid Passage 40 Pressure Liquid Hose 41 Controller 42 Excavation Diameter Display Board 43 Connecting Rod K Underwater Excavator for Downhole

Claims (4)

[Claims] 1. Excavation by a swing arm provided swingably on a swivel support member formed under a swivel inner cylinder in a main body of an underwater excavator for pits suspended from the water through a steel pipe pile. In a method for detecting an excavation diameter of a vertical hole underwater excavator in which a portion is swingably provided with respect to the excavator main body, for excavating the excavation portion by swinging the excavation arm by swinging the excavation portion. The amount of working hydraulic fluid sent to the hydraulic cylinder is measured by an excavation diameter detector provided in the second synchronous cylinder, the change in the hydraulic fluid amount is converted into an electric signal, and the swing signal is converted by the computer using the electric signal. A method for detecting an excavation diameter of an underwater excavator for a pit, characterized in that an excavation diameter is detected by calculating a moving amount of a pressure cylinder. 2. Excavation by a swing arm provided swingably on a swivel support member formed below a swivel inner cylinder in a main body of an underwater excavator for pits suspended from the water through a steel pipe pile. In the method for controlling the excavation diameter of an underwater excavator for a vertical hole in which the excavation unit is swingably provided with respect to the excavator main body, a swing for driving the swing arm to swing the excavation unit to change the excavation diameter. The amount of working hydraulic fluid sent to the hydraulic cylinder for operation is measured by the excavation diameter detector provided in the second synchronous cylinder, the change of the hydraulic fluid quantity is converted into an electric signal, and the swinging is performed by the computer using the electric signal. The excavation part is rocked by calculating the moving amount of the hydraulic cylinder to detect the excavation diameter, and controlling the amount and the flow direction of the working pressure liquid sent to the rocking hydraulic cylinder by the first synchronous cylinder. Characterized by changing the excavation diameter Excavation diameter detection control method for underwater excavator for vertical holes. 3. Excavation by a swing arm provided swingably on a swivel support member formed at the lower part of a swivel inner cylinder in a main body of an underwater excavator for pits suspended from the water through a steel pipe pile. In the excavation diameter detecting and displaying device of the underwater excavator for a vertical hole in which a portion is swingably provided with respect to the excavator body, a swing for changing the rotary excavation diameter of the excavating portion between the swivel support member and the swing arm. A dynamic hydraulic cylinder is provided, and the working hydraulic fluid to the rocking hydraulic cylinder is sent by the second synchronous cylinder to change the amount of the hydraulic fluid measured by the excavation diameter detector provided in the second synchronous cylinder. An underwater excavator for a pit, characterized in that the excavation diameter is displayed on an excavation diameter display panel by calculating the movement amount of the rocking hydraulic cylinder using a computer based on the electrical signal Excavation diameter detection display device. 4. Excavation by a swing arm provided swingably on a swivel support member formed below a swivel inner cylinder in a main body of an underwater excavator for pits suspended from the water through a steel pipe pile. In an excavation diameter detection and display control device for an underwater excavator for a vertical hole in which a portion is swingably provided with respect to the excavator body, the rotary excavation diameter of the excavation portion is changed between the swivel support member and the swing arm. An oscillating hydraulic cylinder is provided, and the working hydraulic fluid to the oscillating hydraulic cylinder is sent by a second synchronous cylinder,
The change in the amount of pressure fluid measured by the excavation diameter detector provided in the second synchronous cylinder is converted into an electric signal, and the movement amount of the rocking hydraulic cylinder is calculated using a computer by the electric signal, and the excavation is performed. The diameter is displayed on the excavation diameter display panel, and an operating device for controlling the amount and the flow direction of the working pressure liquid sent to the rocking hydraulic cylinder is provided, and the first synchronizing cylinder is operated by the operating device. The excavation of an underwater excavator for a vertical hole, characterized in that the excavating portion is swung to change the excavating diameter by controlling the amount and flow direction of the working hydraulic fluid sent to the swing hydraulic cylinder. Diameter detection display control device.