JPH04327687A - Excavator for soil - Google Patents

Abstract

PURPOSE:To prevent the clogging of stone, gravel, etc., having large grain size in a suction path, and to increase suction force in an excavator for soil constituted so as to suck up crushed soil and sand by negative-pressure suction force generated in the hollow cylinder of an excavating cylinder and transfer and discharge crushed soil and sand. CONSTITUTION:A cutting tip 46 is mounted and blowholes 45 for compressed air are formed on the circumferential section of the lower end of an excavating cylinder port 40a formed at the lower end of a rotated and driven hollow excavating cylinder 40. The negative-pressure suction force of a blower for vacuum suction is introduced into the internal opening 40c of the excavating cylinder port 40a by a vacuum duct 15, and compressed air from a blast source is introduced into the blowholes 45 by a hose 53. The cutting tip 46 and the blowholes 45 are turned with the revolution of the excavating cylinder port 40a and soil and sand are crushed, and crushed soil and sand are sucked into the hollow cylinder 42 of the excavating cylinder 40 by strong suction force extending over a wide range in an elliptical suction opening section in the internal opening 40c of the excavating cylinder port 40a revolved to the axis of rotation.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a soil excavation device that pneumatically crushes the soil surface using pressurized air and sucks and discharges the crushed soil by sucking up the crushed soil using vacuum suction force. In a soil excavation device that is capable of simultaneously performing air crushing of soil and suction and removal of crushed soil through an upright hollow excavation cylinder, the air intake path is clogged with large-sized soil clods. The present invention relates to a soil excavation device that can prevent such problems and has good suction efficiency.

0002

[Prior Art] When excavating soil under roads, etc.,
Because piping such as gas piping, water piping, or cable passages are buried in the soil, the bucket is moved into the soil using mechanical force like a generally known shovel-type excavator. With excavators of the type that plunge into the soil, problems occur during excavation work, such as the bucket being driven into the soil crushing and damaging buried objects, or digging up and destroying buried objects.

[0003] As an excavator that does not damage or destroy objects buried in the ground, there has been a conventional excavator, for example, disclosed in Japanese Patent Application Laid-Open No. 58-22222.
A vacuum excavator shown in the prior art described in Publication No. 8 is known. This vacuum excavator is equipped with an earth and sand suction port at the tip of a vacuum hose connected to a suction blower, and the operator points the earth and sand suction port of the hose to face the soil surface to be excavated. According to this type of vacuum excavator, excavation progresses by sucking up the earth and sand using the suction force from the blower. Problems such as damage or destruction of buried structures will not occur.

0004

[Problem to be Solved by the Invention] Conventionally known vacuum excavators only have the function of sucking up earth and sand using the vacuum suction force from a blower, and do not have the function of crushing the soil surface to be excavated. Therefore, before excavation work, it is necessary for the worker to break down the soil surface at the excavated location using a separately prepared excavation rod or the like and crush the soil to a state that can be sucked and removed in advance.

[0005] For this reason, excavation work not only requires another worker, but also has the inconvenience of linking the work process of breaking down the soil surface in advance, and the work of breaking down the soil surface must be done manually. Not only does this involve very hard labor, but manual soil breaking work has limited capacity and requires a great deal of time.

In view of these problems, the present invention is based on a vacuum excavation method that does not damage or destroy buried objects.
In addition to simultaneously and efficiently performing the function of breaking down the soil surface and suctioning and discharging soil, it also narrows the entrance of the suction path to prevent large particles of soil from entering and blocking the suction path. Furthermore, it is an object of the present invention to provide a soil excavation device that can strengthen the vacuum suction force at the earth and sand suction port.

[0007]

[Means for Solving the Problems] In order to achieve this object, an apparatus according to the present invention includes a vacuum suction blower, a sediment collection chamber provided in communication with a suction path of the blower, and a vacuum pump in the sediment collection chamber. The excavation tube has a hollow excavation tube that communicates with the excavation tube through a duct. In a soil excavation device configured to air-freak air to crush the soil surface, the crushed soil is sucked into a hollow excavation tube communicating with a vacuum duct, and the soil is transferred and discharged. has an excavation tube mouth with a larger diameter at its lower end, and the excavation tube mouth has a blowhole at its lower circumference that communicates with a blowing source and blows pressurized air toward the soil surface, and a lower circumferential edge. The cutting tip protrudes further downward and is fixed, and means for rotating the excavation tube in one direction or in a reciprocating direction in the circumferential direction, and the internal opening of the excavation tube mouth has an upper end that serves as a suction passage for earth and sand. The hollow cylinder has a circular shape with the same diameter as the inner diameter of the hollow cylinder, and the suction port at the lower end is opened in an oval shape extending in the radial direction of the excavation cylinder opening with a width smaller than the diameter of the circular cylinder at the upper end. . Further, the internal opening of the excavation tube mouth described above is characterized in that the suction port at the lower end thereof is opened in an oval shape deviated in the radial direction of the excavation tube mouth.

[0008]

[Operation] According to the excavation device configured as described above, the hollow excavation tube that stands upright on the soil surface can be accessed from the circumference of the excavation tube opening formed at the lower end of the excavation tube. Pressurized air is blown towards the soil surface of the enclosed compartment area,
The air pressure is used to break down the soil surface. In addition, at this time, a cutting tip is provided on the circumference of the lower end of the above-mentioned excavation tube mouth, which is attached to the blowhole and projects downward. Since it rotates in the direction, the cutting tip mentioned above rotates while disturbing the stones, etc. that are interposed in the soil, and this disturbance effect, combined with the effect of air pressure, causes the soil to collapse extremely. This is effectively accomplished and the crushed soil can be broken down into fine particles that are easy to transport by air current.

In this process, a negative pressure suction force is applied to the lower end of the excavation tube opening through the hollow tube of the excavation tube leading to the vacuum duct, so that the above-mentioned crushed earth and sand flows from the internal opening of the excavation tube mouth into the hollow tube. The soil is sucked up into the soil collection chamber from its upper end via a vacuum duct.

[0010] At this time, the internal opening of the excavation tube mouth has a circular shape whose upper end has the same diameter as the inner diameter of the hollow cylinder of the excavation tube, which serves as a suction passage for earth and sand, and the suction opening at the lower end is smaller in diameter than the circular diameter at the upper end. Since the opening is oval in width and extends in the radial direction of the excavation tube mouth, it will not suck in large-sized earth clods that may get caught in the suction path such as the earth and sand suction path or vacuum duct. Further, the negative pressure for suction is increased because the suction port at the lower end is formed to have a width smaller than the diameter of the circular hole at the upper end, and the suction force at the suction port becomes strong. Further, since the suction port at the lower end is an oblong hole extending in the radial direction of the excavation tube mouth, earth and sand can be sucked in from a wide range as the excavation tube mouth rotates. Furthermore, if the hole in the suction port has an oval shape that is offset in the radial direction of the excavation tube mouth, the hole in the suction port revolves around the rotation center of the excavation tube mouth, so that a wide area of the earth and sand can be sucked. Although it has a large area, it can have a narrow opening area, so the suction efficiency is even better and it does not suck in clods with large particle sizes. As a result, the suction and transfer action of the crushed earth and sand is smoothed, and the action of pushing down the soil and suction and discharging of the crushed earth and sand are simultaneously and efficiently carried out by the excavation cylinder mouth that is set upright on the soil surface, and the excavation cylinder is Soil excavation is carried out in such a way that it penetrates deeply into the soil and forms holes of the required depth on the soil surface.

[0011]

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings. In FIG. 1, 1 is a low-floor truck that serves as the main body of the vacuum excavator, and the front part is equipped with a driver's seat 2. On the chassis 3 of the truck 1, there is an engine 4 and
It is equipped with a vacuum suction blower 5 driven by a vacuum suction blower 5, a box-shaped filter chamber 6 installed on the suction path of the blower 5, and a sediment collection chamber 7 communicated with this. This is a more well-known one.

The vacuum suction blower 5 is communicated with the filter chamber 6 via a communication pipe 8 connected to its suction path. The filter chamber 6 is vertically partitioned by a partition plate 6c into an exhaust chamber 6a at the upper part and a suction chamber 6b at the lower part, and the communication pipe 8 is communicated with the exhaust chamber 6a divided at the upper part. A plurality of bellows-shaped filter bags 9 are suspended from the partition plate 6c and are suspended in the lower suction chamber 6b. The support plate 10 is connected and fixed, and the support plate 10 is elastically supported on the bottom wall surface of the filter chamber 6 via a tension coil spring 11. The suction airflow in the filter chamber 6 enters the filter bag 9 through the opening provided in the support plate 10 as shown by the arrow, passes through the cylindrical wall of the filter bag 9, and passes through the outlet opening provided in the upper partition plate 6c. The structure is such that fine dirt particles mixed into the airflow in the process of flowing into the upper exhaust chamber 6a are removed by a filtering action, and the bottom of the filter chamber 6 is connected to the dirt collection chamber 7 through a communication path 12. It is connected to the top of the.

The earth and sand collection chamber 7 has an earth and sand inlet 7a opened at a high position on the rear wall, and a flexible vacuum duct 15 is connected to this. Above earth and sand inlet 7
Collision plate 1 disposed obliquely in collection chamber 7 opposite to a
3 is elastically supported to be movable up and down using one end as a fulcrum, and when the earth and sand that is suctioned and injected from the earth and sand inlet 7a through the vacuum duct 15 collides with this collision plate 13, the earth and sand with high specific gravity collide. The dirt falls downward and accumulates at the bottom of the collection chamber 7, and a light air flow bypasses the upper part of the collection chamber 7 and flows from the communication passage 12 to the bottom of the filter chamber 6. The bottom of the earth and sand collection chamber 7 has a door 14 that can be opened and closed, and by opening this door, the collected earth and sand accumulated at the bottom can be discharged to the outside.

In the present invention, a connecting fitting 1 having a U-shaped cross section extending in the left-right direction is provided at the rear of the chassis 3 of the truck 1.
8, and a boom 20 extending in the front-rear direction is connected to this connecting fitting 18 via a hitch pin 19. The boom 20 has an inner cylinder 2 with respect to an outer cylinder 20a so as to be able to expand and contract.
A mounting plate 21 is fixedly installed at the end of the inner cylinder 20b, and a boot is inserted through the mounting plate 21 into the inner cylinder 20b.
A support pedestal 22 for the excavation device is removably fixed to the end of the ram 20. The support frame 22 is connected to the mounting plate 21.
A vertical frame with a mounting plate 23 bonded and fixed to the
A lifting guide column 27 is installed vertically through support members 25 and 26 attached to the upper and lower ends of the vertical frame 24, and a hydraulic cylinder mechanism 28 is connected to the lower part of the vertical frame 24. It has a pair of left and right outriggers 29 that can be extended and retracted up and down, and a moving wheel 30.
By bringing the support frame 22 into contact with the soil surface, the support frame 22 can be grounded and fixed to the soil surface.

FIG. 2 is a cross-sectional view showing a first embodiment of the excavation apparatus according to the present invention, in which a lifting guide column 27 provided on a support frame 22 has a rack 27a formed on one side of the column made of square pipe material. The guide column 27 has an elevating body 35 that moves up and down along the guide column 27.
The support 27 is supported by a pinion 32 meshing with the pinion 7a and a pair of rollers 33 and 34 provided opposite to the support 27 so as to be raised and lowered. A handle 36 for lifting and lowering is provided at the end of the shaft of the pinion 32, and by rotating this handle 36, the lifting body 35
can be raised and lowered along the guide column 27, and although not shown, the elevating body 35 is equipped with a locking mechanism that restricts the rotation of the pinion 32, so that the elevating body 35 can be fixed at an appropriate position in the raised position. That's what I do. The above-mentioned elevating body 35
In this case, a hollow cylinder 42 is inserted into the excavation cylinder 40 via a fixture 35a provided therein, and is fixed vertically so that the axis of the cylinder stands upright on the soil surface. The hollow cylinder 42 has a double wall including an inner wall 42a and an outer wall 42b, and an annular air passage 43 is formed between both walls 42a and 42b.
The inside of the cylinder of the inner wall 42a is a hollow earth and sand suction passage 42c extending vertically, and the tip of the vacuum duct 15 is connected to the upper end of the hollow earth and sand suction passage 42c.

An excavation cylinder 40 is rotatably fitted on the outside of the hollow cylinder 42, and the excavation cylinder 40 is prevented from coming off in the axial direction of the hollow cylinder 42, and a cylinder is attached to the lower end of the excavation cylinder 40. A large-diameter excavation tube mouth 40a is formed. This excavation tube mouth 40a does not necessarily have to have a larger diameter than the excavation tube 40, but a larger diameter will reduce the contact area between the peripheral wall of the excavation tube 40 and the soil during excavation, which will be described later. This is preferable because the excavation tube mouth 40a can be easily rotated, and furthermore, it can be easily pulled out after excavation. This excavation tube mouth 4
As shown in FIG. 3, which is a view taken along the line A-A in FIG. Further, cutting tips 46 as disturbance blades having a required width protrude downward at four locations in the circumferential direction at the outer peripheral edge of the lower end of the excavation cylinder mouth 40a, out of phase with the jet nozzle 45. Fixed. Further, an internal opening 40b is opened at the center of the excavation tube mouth 40a. This internal opening 40
b is a circular hole whose upper end has the same diameter as the inner diameter of the hollow cylinder 42 which becomes the earth and sand suction passage 42c;
2c, and transforms into an oblong hole that extends in the radial direction as it reaches the suction port at the lower end, as shown in the figure. The width W of the oval hole (suction port) is as shown in FIG.
The length L is smaller than the passage diameter of the earth and sand suction passage 42.
Make it larger than the passage diameter of c. And the earth and sand suction passage 42c
The area of the hole in the suction port is slightly smaller than the cross-sectional area of the hole. In this way, (cross-sectional area) x (flow velocity) = (
(constant), the flow velocity in the suction part becomes faster, and the suction efficiency improves. Furthermore, since large-sized soil clods are regulated by the width W of the hole in the suction port, there is no risk of them clogging the suction path.

In this embodiment, the elevating body 35 is provided with a hydraulic motor 48 fixed via a support fitting 47, and this hydraulic motor 48 is driven by the hydraulic system installed in the truck 1. A pinion gear 49 attached to the drive shaft of the hydraulic motor 48 and a drive gear 5 that meshes with the pinion gear 49
0, the excavation cylinder 40 is rotated at a reduced speed in one circumferential direction or in a reciprocating direction. Further, an air hose 51 is connected to the upper part of the hollow cylinder 42 in communication with an air passage 43 formed between the inner wall 42a and the outer wall 42b of the hollow cylinder 42, and in the illustrated embodiment, the tip of the air hose 51 is , is connected to the exhaust system of the vacuum suction blower 5 mounted on the chassis 3 of the truck 1, and the exhaust from the blower 5 is connected to the hose 5.
1 to the air passage 43, and the blowing means is configured to direct the air to the air passage 43 and blow it as pressurized air from the blowhole 45 onto the soil surface.

FIG. 4 is a cross-sectional view showing a second embodiment of the excavation apparatus according to the present invention, and FIG. 5 is a view taken along the line B--B in FIG. In this embodiment, an internal opening 40c provided at the center of the excavation tube mouth 40a has a circular shape at its upper end having the same diameter as the earth and sand suction passage 42c, and communicates with the earth and sand suction passage 42c smoothly and rotatably. The hole deforms into an oblong hole as it reaches the suction port at the lower end, and is further opened offset in the radial direction of the excavation tube opening 40a. In this second embodiment, the internal opening 40b is inclined compared to the first embodiment shown in FIGS. 2 and 3,
The only difference is that the hole in the suction port at the lower end is offset, and the rest is the same, so corresponding components are given the same reference numerals and explanations are omitted. In this embodiment, the internal opening 4
0b revolves around the center of rotation as the excavation tube opening 40 rotates because the hole of the suction port at the lower end thereof is offset in the radial direction of the excavation tube opening 40a. Therefore, the hole of the suction port at the lower end of the internal opening 40b comes into contact with the orbit and sucks the earth and sand. Therefore, even if the length L' of the oval hole is short, the effective area for suctioning the earth and sand does not decrease, and earth and sand can be efficiently sucked from the entire area surrounded by the lower end of the excavation tube mouth 40a. Moreover, compared to the first embodiment, there is less risk of suctioning elongated foreign objects, and the suction force becomes even stronger.

Next, an example of use and operation of the excavating apparatus constructed as described above will be explained. During excavation work, the truck 1 is moved to the place to be excavated, and the support pedestal 22 installed at the end of the boom 20 is first placed on the soil surface to be excavated so that the excavation cylinder 40 stands upright above it. is fixed to the ground by a pair of left and right outriggers 29. In this state, the lifting body 35 is moved by operating the handle 36.
The lifting guide column 27 is lifted to the raised position, thereby raising the excavation tube 40 and setting the excavation tube mouth 40a at the lower end thereof to be in contact with the soil surface level. At this time of setting, the excavation tube 40 has a lower end of the excavation tube opening 40a exerting a required pressing force against the soil surface due to the weight of the hollow tube 42, the elevating body 35, etc. that support it, and the guide column 27.
It is in a state of falling under its own weight along . If the above-mentioned pressing force is insufficient in terms of weight, add a separate weight, and if a larger pressing force is required due to hard or soft soil, rotate the handle 36 as necessary during the excavation operation. Alternatively, the excavation tube mouth 40a may be pressed and biased in the downward direction.

After the above-mentioned setting is completed, the engine 4 is started and the vacuum suction blower 5 is operated, and at the same time, the hydraulic motor 48 is driven by the hydraulic system installed in the truck 1 to move the excavation tube 40 in one direction or in a reciprocating direction. Rotate at a reduced speed. As a result, the vacuum suction force from the suction blower 5 is transferred from the communication pipe 8 to the filter chamber 6 to the sediment collection chamber 7 to the vacuum duct 1.
5→ acts on the earth and sand suction passage 42c in the cylinder of the hollow cylinder 42 that rotatably supports the excavation cylinder 40, and a suction upward airflow is generated in the cylinder. Meanwhile, at the same time, exhaust air (pressure air) from the suction blower 5 is passed through the hose 51 to the hollow cylinder 42.
The pressurized air is introduced into an air passage 43 formed between an inner wall 42a and an outer wall 42b, and the pressurized air is emitted from a blowhole 45 of an excavation cylinder mouth 40a opened in communication with the air passage 43.

At this time, the above-mentioned pressurized air is atomized against the soil surface divided by the excavation tube opening 40a at the lower end of the excavation tube 40, and the fume of the pressurized air is concentrated in the soil surface to be excavated. Therefore, the air pressure efficiently contributes to the crushing action of the soil surface, and the soil surface is broken down by the air pressure. Further, in this case, the excavation tube 40 is rotated at a reduced speed in the circumferential direction, and the cutting tip 46 fixed to the outer peripheral edge of the lower end of the excavation tube mouth 40a rotates while disturbing stones, etc. interposed in the soil. Therefore, together with this disturbance effect, the above-mentioned soil upheaval by air pressure is effectively carried out. This air-crushed earth and sand floats within the internal opening 40b of the excavation tube mouth 40a due to the reaction of the pressurized airflow ejected onto the soil surface, and this floating process promotes the finer grains of the earth and sand, while the excavation tube 40 It flows so as to be immediately sucked up by the negative pressure suction force generated in the rotating internal opening 40b connected to the earth and sand suction passage 42c in the hollow cylinder 42, and there is no risk of clogging the earth and sand suction passage 42c or the vacuum duct 15. The suction of soil clods with a certain large particle size is prevented by the oval hole at the lower end of the suction port, so the flow of the soil is smooth and without clogging, and the suction of the soil is prevented. The soil is collected and discharged from the upper part of the hollow cylinder 42 into the soil absorption chamber 7 through the vacuum duct 15.

Further, in the case of the second embodiment in which the internal opening 40b is an oblong hole with an inclined lower end, as described above, the suction port at the lower end of the internal opening 40b is Despite the short length L' of the hole, the suction action area is wide, and the possibility of clogging the suction path by suctioning large-sized earth clods is further reduced, and moreover, the suction force is improved. As a result, the action of crushing the soil surface and the suction action of the crushed earth and sand proceed simultaneously through the hollow excavation tube 40 that is erected on the soil surface, and as this progresses, the excavation tube 40 , the excavation work is performed so that the excavation tube mouth 40a penetrates deeply into the soil by sequentially descending along the elevating guide column 27 to form a hole of the required depth. During this excavation work, if various types of piping such as gas pipes and water pipes are buried in the soil to be excavated, the excavation tube 40 is moved to the guide support 27 via the elevating body 35 by its own weight or by human power. Since it is configured to descend and stop descending when it comes into contact with a buried object, there is no problem of damaging or destroying the buried object.

[0023]

[Effects of the Invention] As explained above, according to the excavation device according to the present invention, the function of crushing (breaking down) the soil surface using air pressure and the function of suctioning and discharging crushed earth and sand using vacuum force are as follows.
Since the excavation tube 40 is placed upright on the soil surface, it is simultaneously carried out, so that it does not damage buried objects existing in the soil to be excavated.
Compared to vacuum excavators that have been used in the past as non-destructive excavators, excavation work can be carried out extremely efficiently. Further, the excavation tube 40 includes a cutting tip 46 that is provided at the lower circumference of the excavation tube opening 40a and protrudes downward along with a blowhole 45.
An excavation tube 40 provided with an excavation tube opening 40a.
Since this rotates in the circumferential direction about the cylindrical shaft, the above-mentioned cutting tip 46 rotates while disturbing stones, etc. interposed in the soil, and this disturbing action is also mutually effective. As a result, the above-mentioned soil upheaval action by air pressure is achieved extremely effectively, and the disturbance action turns the crushed earth and sand into fine particles that are easily transported by airflow, so the above-mentioned suction and removal action of the earth and sand can also be facilitated. . In particular, the suction port at the internal opening 40b of the excavation tube mouth 40a described above is formed into an oval hole, so that it does not suck in large-sized earth clods that may become clogged in the suction path. Since the flow path is narrowed at the suction port of the route, the flow velocity at the suction port increases and a strong negative pressure suction force is obtained, which facilitates the suction of crushed earth and sand. The transport of earth and sand becomes smoother, and the suction and removal of crushed earth and sand becomes much more efficient. Furthermore, if the hole in the suction port is opened offset in the radial direction of the excavation tube mouth, even though the length of the hole in the suction port is short,
The suction area does not decrease, the holes can be made smaller, and the suction of large-grained clods is reduced, and the suction power is further improved.

[Brief explanation of drawings]

FIG. 1 is an overall side view, partially in section, of an embodiment of a drilling device according to the present invention.

[Fig. 2] A side view of the first embodiment of the soil surface excavation device, enlarged and partially shown in cross section.

[Figure 3] A-A arrow view in Figure 2

FIG. 4 is an enlarged side view showing a part of the second embodiment of the soil surface excavation device in cross section.

[Figure 5] B-B arrow view in Figure 4

[Explanation of symbols]

1 truck 2 driver seat
3 Chassis 4 Engine 5 Blower
6 Filter chamber 6a Upper exhaust chamber 6b Lower suction chamber
6c Partition plate 7 Sediment collection chamber 7a Sediment inlet 8 Communication pipe 9 Filter bag 10 Support plate
11 Tension coil spring 12 Passage 13 Collision plate 14 Door 15 Vacuum duct
18 Connecting fittings 19 Hitch pin 20 Boom
21, 23 Mounting plate 22 Support frame 24 Vertical frame
27 Elevating guide column 27a Rack 28 Hydraulic cylinder mechanism 29 Outrigger 32 Pinion 33, 34 Roller 35 Elevating body 36 Elevating handle 40 Excavation tube 40a Excavation tube mouth 40b Internal opening
42 Hollow cylinder 42c Sediment suction passage 43 Air passage
45 Fumarole

Claims (2)

[Claims] 1. A vacuum suction blower, an earth and sand collection chamber provided in communication with a suction path of the blower, and a hollow excavation cylinder connected to the earth and sand collection chamber via a vacuum duct, The excavation tube is supported by a support member so as to be able to rise and fall vertically with its hollow axis standing upright on the soil surface, and pressurized air is blown from the bottom end of the excavation tube to air crush the soil surface while crushing the crushed earth and sand. In a soil excavation device configured to transfer and discharge soil by suction into a hollow excavation tube connected to a vacuum duct, the hollow excavation tube has an excavation tube opening with a large diameter at its lower end. The opening of the excavation tube includes a blowhole that communicates with a blowing source and blows pressurized air toward the soil surface at the lower circumference, a cutting tip that protrudes downward from the lower circumference and is fixed, and a cutting tip that extends around the circumference of the excavation tube. The internal opening of the excavation tube mouth is circular with the same diameter as the inner diameter of the hollow cylinder of the excavation tube whose upper end serves as a suction passage for earth and sand, and the suction port at the lower end. 1. A soil excavation device characterized in that the opening has an oval opening extending in the radial direction of the excavation tube mouth with a width smaller than the diameter of the circular shape at the upper end. 2. The soil excavation device according to claim 1, wherein the internal opening of the excavation tube opening has an oval shape with a lower end suction port deviated in the radial direction of the excavation tube opening.