JP2020125646A - Drilling tool - Google Patents

Abstract

To provide a drilling tool capable of drilling hard bedrock, even if it is a small drilling tool to be attachable to a pole electing vehicle.SOLUTION: A drilling tool has a bit shaft, a tip bit having a cemented carbide tip provided at the tip of the bit shaft, and an auxiliary bit provided at a lower position apart from the tip bit, and the tip bit has a pyramid shape with a cemented carbide tip as a side at its tip, and has drilled soil discharge groove for discharging drilled soil on a triangular pyramid surface forming its pyramid, and the auxiliary bit is the drilling tool composed of an inner auxiliary bit and an outer auxiliary bit, which are provided on the outer periphery of the bit shaft at equal intervals and alternately. In addition, a diameter-expanding drilling member that has a block for a mounting base, a plurality of side surface bits mounted on the front surface or both front and rear surfaces in the rotational direction of the block, and the carbide cemented tip at the tip of a side bit is combined to the drilling tool.SELECTED DRAWING: Figure 7

Description

The present invention relates to an excavating tool used for excavation work for utility pole holes, support piles, and the like.

Conventionally, in order to install utility pole hole excavation and support piles, work is carried out by large excavating machines such as percussion, breakers, and excavating machines. However, if the work place is a narrow place such as a residential area, there is a risk of damaging nearby buildings and electric wires, and it is difficult to use a large excavating machine. Even if a large excavator could be used, the large vibration, noise, and dust generated by excavation adversely affect the living environment of the residents, so a small excavation tool that can excavate hard rock is required. There is.

For example, Patent Document 1 relates to an excavating tool that is a small excavating machine and is capable of excavating hard rock, and has a small diameter bit at the tip, a medium diameter bit at the middle, and a large diameter at the base end. There is described a vertical hole excavating bit in which the diameter bits are detachably assembled and connected.

Further, Patent Document 2 describes a bit device that is intended for excavation of hard ground and that includes a large number of bit units including at least trench bits and hole down bits.

Further, in Patent Document 3, a cutter having a center shaft for discharging a drilling fluid for reducing frictional resistance and cooling, and a plurality of cone-shaped cutters in which a plurality of chips are planted on a peripheral wall revolving around the center shaft are provided. The head is listed.

JP-A-11-50773 JP, 2014-237947, A JP, 2011-236560, A

The vertical hole excavating bit described in Patent Document 1 has a problem in that it is necessary to mount three bits for changing the excavation diameter, and the mounting requires time and effort. Further, since there is no bit for excavating the hole wall and the interval between the bits is wide, there is a problem that the rock of the hole wall comes into contact with a place other than the bit and it is difficult to excavate the hard rock.

The bit device described in Patent Document 2 is capable of excavating hard rock, but since it has two types of cutting bits, a trench bit and a hole down bit, its structure is complicated and manufacturing costs increase. Besides, there is a problem that a torque of 10 to 18 kN·m is required for rock excavation, which cannot be used by a small excavating machine that can be mounted on a column.

The cutter head described in Patent Document 3 is very effective for excavating a large diameter in soft ground, but in excavation of hard rock, small stones and rock fragments are caught in the gap between the conical cutter heads. However, there is a problem that smooth excavation is difficult because the cutter head produces frictional heat.

Then, this invention aims at providing the small excavation tool which can excavate a hard rock.

As a result of earnest studies, the inventors of the present invention can excavate hard rock even if the excavation tool is small enough to be mounted on a building column car by devising the shape of the tip bit or the like. The present invention has been achieved based on the knowledge that

The present invention is
“(1) A drilling tool having a bit shaft, a tip bit having a carbide tip provided at the tip of the bit shaft, and an auxiliary bit provided at a lower position apart from the tip bit. The tip bit is in the shape of a pyramid whose tip is the carbide tip, and the triangular pyramid surface forming the pyramid has an excavated soil discharge groove for discharging excavated soil, and The auxiliary bit comprises an inner auxiliary bit and an outer auxiliary bit, which are provided on the outer periphery of the bit shaft at equal intervals and alternately, and are provided.
(2) The drilling tool according to (1), wherein the pyramid of the tip bit is any one of a quadrangular pyramid and an octagonal pyramid.
(3) The excavated soil discharge groove is provided on at least one pair of opposing surfaces of the pyramidal surface, and has a curved shape toward the lower side of the bit axis, (1) or (2) The drilling tool described in.
(4) The excavation tool according to any one of (1) to (3), wherein the excavated soil discharge groove is two to four.
(5) The inner auxiliary bit and the outer auxiliary bit are provided in a cross shape in the cross direction of the bit shaft, and a cemented carbide tip is attached to the tip thereof, (1) to () The excavating tool according to any one of 4).
(6) The inner auxiliary bit is arranged such that the excavation track of the cemented carbide tip is inside the excavation track of the cemented carbide tip of the outer auxiliary bit. ) A drilling tool according to any one of (1) to (4).
(7) The tool for excavation according to any one of (1) to (6), wherein the inner auxiliary bit is disposed below the excavated soil discharge groove.
(8) A drilling tool comprising the drilling tool according to any one of (1) to (7) in combination with a diameter expanding drilling member, wherein the diameter expanding drilling member is a mounting block. And a plurality of side surface bits attached to the front surface or both front and rear surfaces of the block in the rotation direction, and a carbide tip is attached to the tip of the side bit. Tools.
(9) The excavating tool according to (8), wherein the diameter-expanding excavating member has an inclined block front plate with an inclined surface attached to a front surface in the rotation direction of the block. ..
(10) The diameter-expanding excavation member has an outer diameter bit attached outside the left and right ends of the block, or outside the left and right ends of the block and the inclined block front plate. The tool for excavation according to (8) or (9) above, wherein a carbide tip is attached to the tip of the outer diameter bit.
(11) The excavating tool according to any one of (8) to (10), wherein a plurality of the side surface bits are arranged on both left and right sides of the block while changing center radii thereof.
(12) In the above (11), a plurality of side surface bits arranged on both left and right sides of the block are arranged so that loci in a rotation direction around the bit axis overlap. Excavation tool as described.
(13) The side bits are arranged such that the vertical height of the side bits is high in the inside close to the center of the bit axis and gradually decreases toward the outside. The excavating tool according to any one of (12). "
Is.

According to the present invention, it is possible to excavate hard rock even if the excavation tool is small enough to be mounted on a column.

It is a front view of one embodiment of the drilling tool of the present invention. It is a left side view of one embodiment of the drilling tool of the present invention shown in Drawing 1A. 1B is a plan view of an embodiment of the excavation tool of the present invention shown in FIG. 1A. FIG. It is the figure which added the shade to the top view of one Embodiment of the drilling tool of this invention shown in FIG. 1C. It is a perspective schematic diagram of one Embodiment of the drilling tool of this invention shown to FIGS. 1A-1D. It is a perspective schematic diagram of other embodiment of the drilling tool of this invention. It is one embodiment of the member for diameter expansion drilling of the present invention, and is a schematic perspective view in which a side surface bit, an outside diameter bit, and an inclined block front plate are arranged. In one embodiment of the member for diameter expansion excavation of the present invention, it is an explanatory view of the position which provides a side bit and an outside diameter bit based on the top view of the member for diameter expansion excavation. FIG. 5 is a diagram showing excavation trajectories of a side bit and an outer diameter bit in the embodiment of the member for expanding diameter drilling of the present invention shown in FIG. FIG. 3 is a schematic perspective view of an embodiment in which the drilling tool of FIGS. 1A to 1D or FIG. 2 of the present invention and the diameter-expanding drilling member of FIG. 4 are combined. It is a front view of other embodiment of the member for diameter expansion drilling of the present invention. It is a top view of the member for diameter expansion excavation shown in FIG. 8A. It is a front view of other embodiment of the member for diameter expansion drilling of the present invention. It is a top view of the member for diameter expansion excavation shown in FIG. 9A. It is a front view of other embodiment of the member for diameter expansion drilling of the present invention. It is a top view of the member for diameter expansion excavation shown in FIG. 10A. It is a front view of other embodiment of the member for diameter expansion drilling of the present invention. It is a top view of the member for diameter expansion excavation shown in FIG. 11A. It is a front view of other embodiment of the member for diameter expansion drilling of the present invention. It is a top view of the member for diameter expansion excavation shown in FIG. 12A.

Hereinafter, description will be given based on an embodiment of the present invention. The present invention is not limited to this one embodiment. Various modifications can be made to the following embodiments within the same and equivalent scope as the present invention.

The excavating tool of the present invention is the excavating tool 2 of the embodiment shown in FIGS. 1A to 1D and FIGS. 2 and 3. Further, the excavating tool of the present invention is the excavating tool 1 shown in FIG. 7 in which a diameter-expanding excavating member 5 is detachably combined with the excavating tool 2 as required. Is used when excavating a hole having a size exceeding the excavation diameter of the excavation tool 2.

Hereinafter, first, the excavation tool 2 and the diameter-expanded excavation member 5 will be described with reference to the drawings.

1. Excavation tool 2
The excavating tool 2 includes a bit shaft, a tip bit having a cemented carbide tip provided at the tip of the bit shaft, an auxiliary bit provided at a lower position apart from the tip bit, and an excavated soil discharge groove for discharging excavated soil. Have.
Hereinafter, these will be sequentially described with reference to FIGS. 1A to 1D and FIG. 2.

(1) Bit shaft 21
The bit shaft 21 serves as a base for fixing the tip bit 3 and the auxiliary bits 4, 4'(inner auxiliary bit 4 and outer auxiliary bit 4'). The bit shaft base 26 is provided with a bit shaft connecting port 27 so that the tip bit 3 and the auxiliary bits 4, 4'can be excavated, and this serves as a bolt hole for connecting to a ground auger or the like. Further, when combined with the member 5 for expanding the diameter, the bit shaft connecting port 27 becomes a bolt hole which is housed in the non-penetrating hole 61 in the center of the block 6 and connected to the block 6.
The size of the bit shaft 21 (the size from the tip to the block mounting surface 29) can be, for example, 75 mm in diameter and 200 mm in length.

(2) Tip bit 3
The tip bit 3 has a cemented carbide tip 31 provided at the tip of the bit shaft 21, and by the rotation of the bit shaft 21, comes into contact with the ground at the beginning of excavation and excavates a hole having a small diameter. In order to excavate the rock solidly, it is necessary to excavate from a small hole to a gradually larger hole, so that the tip bit 3 has a smaller excavation diameter. Since the tip bit 3 excavates the rock bed first and precedes it, deviation of the excavation position such as skidding does not occur.

The shape of the tip bit 3 is a pyramid in which the tip of the axial center 22 of the bit shaft is the apex and each side (side) is provided with a cemented carbide tip 31 serving as an excavating blade made of cemented carbide. The pyramid may be a triangular pyramid or an octagonal pyramid, but a quadrangular pyramid is particularly preferable. The reason is that the more the sides of the pyramid (the larger the number of the carbide tips 31), the faster the rock can be ground, but on the other hand, the expensive carbide tips 31 increase and the manufacturing cost increases. This is because the excavated soil adheres to the cemented carbide chip 31 and the excavation becomes difficult.

Hereinafter, a case of a quadrangular pyramid (four carbide tips 31) will be described. The four carbide tips 31 have their cutting edges facing the excavation direction (rotational direction of the bit shaft 21), and as shown in FIGS. 1A to 1C, viewed from the tip of the bit shaft 21 (hereinafter, “bit shaft tip view”). It is arranged on the side (side) of the quadrangular pyramid cross. The angle (φ) formed by the center lines of the adjacent cemented carbide chips 31 is preferably 85 to 95 degrees, more preferably 90 degrees. The reason is that within this angle range, the cement-like excavated soil, which will be described later, is avoided from sticking to the cemented carbide chip 31, and the excavated soil is easily discharged.

The angle (ψ) formed by the carbide tip 31 and the axis 22 of the bit shaft is preferably 50 to 70 degrees, more preferably 55 to 65 degrees. The reason is that if it is less than 50 degrees, the cemented carbide tip 31 is likely to be broken, and if it exceeds 70 degrees, the excavation speed is reduced.

(3) Auxiliary bits 4, 4'
The auxiliary bits 4 and 4 ′ are arranged at a lower position apart from the tip bit 3 so as to be separated by a predetermined length, and expand the diameter of the excavation hole formed by the tip bit 3. If this predetermined length is too long, a wasteful time occurs in which the auxiliary bits 4, 4'do not contribute to excavation. On the other hand, if it is too short, excavation by the tip bit 3 and excavation by the auxiliary bits 4, 4'will be performed almost at the same time, making it difficult to excavate the diameter gradually. Therefore, for example, the upper ends of the cemented carbide tips 41, 41' of all the auxiliary bits 4, 4'are located at a position approximately half the length from the tip of the bit shaft 21 to the lower end of the block mounting surface 29, It is preferable to arrange the auxiliary bits 4, 4'.

The auxiliary bits 4 and 4 ′ are composed of the inner auxiliary bit 4 and the outer auxiliary bit 4 ′, and are arranged on the outer periphery (side surface) of the bit shaft 21 at equal intervals and alternately. Here, the inner auxiliary bit 4 is preferably attached at a position below the excavated soil discharge groove 24, which will be described later.

If the number of the auxiliary bits 4 and 4'is larger, the excavation speed is improved. On the other hand, if the number of the auxiliary bits 4 and 4'is too large, the cost is increased and it is not preferable for discharging the excavated soil from the excavated soil discharging groove 24 described later. Therefore, it is preferable that the number of each of the inner auxiliary bit 4 and the outer auxiliary bit 4′ is two.

The inner auxiliary bit 4 and the outer auxiliary bit 4 ′ are mounted in a swastika shape in the cross direction of the bit shaft 21. That is, the inner cemented carbide tip 41 and the outer cemented carbide tip 41 ′ are at the cutting edge of the cemented carbide tip 31 of the tip bit 3 rather than the positions where the inner fixed base 42 and the outer fixed base 42 ′ are attached to the outer periphery of the bit shaft 21. It is provided so as to project in the direction. By doing so, the auxiliary bits 4, 4'become more stressed in the rotational direction.

The inner auxiliary bit 4 has an inner carbide tip 41 attached to the inner fixed base 42, and the outer auxiliary bit 4'has an outer carbide tip 41' attached to the outer fixed base 42'. ..

The carbide tips 41, 41' provided at the tips of the inner auxiliary bit 4 and the outer auxiliary bit 4'are arranged so that the excavation can be easily performed in a direction of approximately 90 degrees with respect to the excavation surface. The wear on the carbide tips 41, 41' is reduced by lightening the load on 4, 4'.

Then, the center of the inner cemented carbide tip 41 constitutes the excavation trajectory of the inner circle (for example, diameter 120 mm), and the center of the outer carbide tip 41 ′ constitutes the excavation trajectory of the outer circle (for example, diameter 160 mm). I am configuring. Further, the inner auxiliary bit 4 is arranged such that the excavation track of the carbide tip (inner carbide tip 41) is inside the excavation trajectory of the outer carbide tip 41' of the outer auxiliary bit 4'. As a result, even if the bit shaft 21 is touched by vibration, the inner auxiliary bit 4 does not enter the excavation track of the outer cemented carbide tip 41', and excavation can be continued.

The inner auxiliary bit 4 is provided with notches B and C, and the outer auxiliary bit 4'is provided with notches A and D, respectively, in order to reduce the resistance to sediment and facilitate the discharge of excavated soil. Further, as shown in FIGS. 1A and 1B, it is preferable that almost half of the slopes of the notches C and D be flush with the center line of the cemented carbide tip 31 of the tip bit 3.

Further, the outer notch 43' is made wider than the inner notch 43 to facilitate excavation of excavated soil.

(4) Excavation soil discharge groove 24
The excavated soil discharge groove 24 is for discharging excavated soil. The tip bit 3 is heated by the progress of excavation and is cooled by water, but at that time, the excavated soil excavated by the cemented carbide tip 31 and water are mixed to form cement-like excavated soil. However, this may stick to the cemented carbide tip 31 and make excavation difficult. Therefore, in order to discharge the cement-like excavated soil, an excavated soil discharge groove 24 is provided on the triangular pyramid surface 23 between the adjacent cemented carbide chips 31 of the tip bit 3. The excavated soil discharge groove 24 preferably has a curved surface 25 in the downward direction, as shown in FIG.

The excavated soil discharge groove 24 may be provided, for example, on only one set of the triangular pyramid surfaces 23 facing each other, or two or more sets of the triangular pyramid surfaces 23, as long as the strength of the bit shaft 21 itself is not adversely affected. It may be provided in two, and it is preferable to provide two to four.

Next, an example of the excavated soil discharge groove 24 provided on the pair of opposed pyramid surfaces will be described in detail.

In one example of the excavated soil discharge groove 24 shown in FIGS. 1A to 1D and FIG. 2 (in FIG. 1D, the excavated soil discharge groove 24 is highlighted by shading), the excavated soil discharge groove 24 is symmetrical with respect to the axis 22 of the bit axis. Is provided as one set (two in total). The excavated soil discharging groove 24 is provided above the inner auxiliary bit 4 and is a groove in which opposing triangular pyramid surfaces are cut off in a curved shape toward the lower side of the bit shaft 21.

That is, as shown in FIG. 2, the excavated soil discharge groove 24 has a left side P of a triangular pyramid surface 23 forming a part of the excavated soil discharge groove 24 that is planar up to a position near the upper end of the cemented carbide tip 41 ′. Is formed on. In addition, the right side Q of the upper end is formed in a planar shape up to a position near the upper end of the cemented carbide tip 41, and the lower end thereof extends from the lower end position Q′ of the flat part to the lower end position P′ of the left side P. And has a shape that is scraped off to form a curved surface 25 (for example, a spherical surface having a curvature radius of 40 mm).

In addition, in the example of the excavated soil discharge groove 24 shown in FIG. 3, a total of four excavated soil discharge grooves 24 are provided on all opposing triangular pyramid surfaces. The excavated soil discharge groove 24 has a length that does not reach the upper end positions of the inner cemented carbide tip 41 and the outer upper tip 41 ′, and has a curved surface 25 at the lower portion thereof.

Further, in the present invention, the excavated soil discharging groove 24 is formed to have such a curved surface 25 so that the excavated soil generated by excavating the tip bit 3 is discharged from the tip bit 3 by the rotation of the bit shaft 21. An excellent effect is obtained in that the fluid flows through the groove 24 to the space formed by the outer cutout portion 43 ′ and can be easily discharged.

2. Expanding excavation member 5
Next, the expanded diameter excavation member 5 used in combination with the excavation tool 2 will be described.
The diameter-expanding excavation member 5 has a block 6 which is a mounting base, and a plurality of side surface bits 7 on the front side or both front and rear sides in the rotation direction of the block 6, and at the tip of the side surface bit. It has a carbide tip 71. In addition, if necessary, the block 6 has a block front plate 9 on the front side in the rotation direction, and if necessary, the outside of the left and right end portions of the block 6 and the sloped block front plate 9 may be formed. It has an outer diameter bit 8 on the outer side.
Hereinafter, these members constituting the member for excavating the enlarged diameter 5 will be described in order with reference to the drawings.

(1) Block 6
The block 6 is for inserting and fixing the bit shaft base portion 26 of the excavating tool 2, and is also connected to an earth auger or the like, and includes a side surface bit 7, an outer diameter bit 8 and an inclined block front plate 9. It also has the function of a fixed base (mounting base).

An example of the schematic shape is as shown in FIG. 4, which is a substantially rectangular parallelepiped in which the vicinity of the non-penetrating hole 61 in the central portion is swollen, and a block which is concentric with the non-penetrating hole 61 at the lower part of the substantially rectangular parallelepiped A shaft 64 is provided. A block shaft connecting port 62 is provided below the non-penetrating hole 61. When the bit shaft base portion 26 of the excavation tool 2 is inserted into the non-penetrating hole 61, the block shaft connection port 62 is integrated with the bit shaft communication port 27 provided in the bit shaft base portion 26 of the excavation tool 2. A bolt hole (for example, φ16) can be formed, and the drilling tool 2 and the block 6 can be fixed by the bolt 28.

Further, the block shaft 64 is provided with a block shaft connecting hole 63. The block 6 and the earth auger or the like of the building car are connected by a bolt inserted into the connection hole 63, the rotational force of the earth auger or the like is transmitted to the block 6, and the side bit 7 of the member 5 for expanding the diameter and the excavating tool. 2. Rotate the tip bit 3, the inner auxiliary bit 4, the outer auxiliary bit 4′, the outer diameter bits 8 and 8′, and the inclined block front plate 9 which are provided as necessary about the same rotation axis. Can be made

The block 6 is made of an alloy having a strength capable of withstanding excavation of hard rock, and is preferably solid. Since the size of the block 6 is determined according to the size of the excavating diameter to be expanded, prepare a block having a size corresponding to a plurality of excavating diameters (for example, 300 mm, 380 mm, 450 mm, 500 mm). Is required.

(2) Side bit 7 and carbide tip 71
The side surface bit 7 is for further expanding the diameter of the hole excavated by the excavation tool 2, and is provided in plural in the block 6, and is provided on the front surface in the rotation direction of the block 6 or both front and rear surfaces in the rotation direction. It is provided by welding, and a carbide tip 71 is attached to its tip. The cemented carbide tip 71 is oriented in the rotation direction (digging direction) and is arranged so that the excavation can be performed in a direction of approximately 90 degrees with respect to the excavation surface.

It is preferable that the number of the side surface bits 7 is large because the excavation speed can be expected to be improved, but the cost is high because the expensive cemented carbide tip 71 is used in large numbers. In addition, it may be difficult to discharge excavated soil. Therefore, it is preferable to determine the number of side-face bits 7 and the mounting position on the block 6 in consideration of the excavation speed, the manufacturing cost, the wear reduction of the cemented carbide tip 71, the easiness of discharging excavated soil, and the like.

Table 1 exemplifies the relationship between the hole diameter for diameter expansion drilling and the number of side surface bits 7. The side surface bits 7 should be provided at the mounting positions "<1> to <4>" shown in FIG. Is preferred. The arrow in the figure indicates the rotation direction of the block 6.

As is apparent from Table 1 and FIG. 5, it is preferable that a plurality of side surface bits 7 are arranged on the left and right sides of the front surface of the block 6 in the rotation direction or both the front and rear surfaces of the block 6 with different center radii. .. By disposing the side surface bits 7 on both front and rear sides of the block 6 in the rotation direction, a distance between the adjacent side surface bits 7 can be secured and the excavated soil can be easily discharged.

Further, in order to reduce the wear of the cemented carbide tip 71 of the side surface bit 7, as shown in FIG. 6, the side surface bit 7 of each of the cemented carbide chips 71 centered on the rotation axis (bit shaft 21) of the block 6 is provided. It is preferable to dispose the excavation track (trajectory) 10 so that there is a slight overlap, for example, about 3 to 5 mm and a non-overlap part. With this arrangement, wear of the cemented carbide tip 71 is reduced in the portion where the excavation track (trajectory) 10 overlaps, and new ground can be excavated in the non-overlapped portion.
Note that FIG. 6 is an example showing the excavation trajectory (trajectory) 10 of “Hole diameter of expanded diameter excavation is φ380” in Table 1, and also illustrates the excavation trajectory of the outer diameter bit 8.

As shown in FIGS. 8A and 9A, etc., the vertical height of the side surface bit 7 is high in the inner side close to the center of the rotary shaft (bit shaft 21) and gradually decreases toward the outer side. Is preferably arranged (the side bit 7 is arranged in an inclined manner). In this way, during excavation, the inner side bit 7 first contributes to excavation, and thereafter the outer side bit 7 sequentially contributes to excavation. The digging surface becomes a mortar shape by expanding the diameter.
When excavating relatively soft ground, the vertical height of the side surface bits 7 may be the same as shown in FIG. 10A.

Since the excavation surface is formed in a mortar shape by the side surface bit 7 of the present invention, when the excavation tool 1 is taken in and out of the excavation hole in order to discharge the residual soil in the excavation hole, the rotary shaft (excavation shaft) is slightly inclined. Even if it is, since it is immediately restored along the mortar-shaped surface, it is possible to prevent the excavation surface from being excavated obliquely (prevention of inclination of the excavation hole).

(3) Outer diameter bit 8, 8'
The outer diameter bits 8 and 8'determine the outer diameter of the excavation hole, and are provided as necessary when excavating while shaving the wall of the excavation hole. Basically, it is possible to excavate a drilling hole of a required size only with the side bit 7, but when the outer diameter bits 8 and 8'are provided, as shown in FIG. It is placed outside the left and right ends of the. If the excavation of the side bit 7 leaves a sufficient gap between the block 6 and the wall of the drill hole so that the block 6 does not contact the hole wall, the outer diameter bit 8 may not be provided.

Specifically, as shown in FIG. 5, when there are two pieces, one piece is attached to each of the left and right end portions of the block 6, and the pieces are attached to the positions shown in the member numbers 8 so that the excavation tracks are substantially the same. You can When the number is three, it is attached to the position 8'outside the inclined block front plate 9 in the position of <2>, and when it is four, it is attached to the outside of the remaining inclined block front plate 9 It can be attached at the position indicated by reference numeral 8'.

Then, cemented carbide tips 81 and 81' are attached to the tips of the outer diameter bits 8 and 8', respectively, and the cemented carbide tips 81 and 81' are excavated in the rotation direction (digging direction) of the block 6. It is preferable to attach it at an angle of approximately 90 degrees with respect to the surface. As a result, the block 6 can rotate with a sufficient clearance with respect to the wall of the drill hole inside the drill track of the outer diameter bits 8 and 8'during drilling. There is no contact with the slab and it will not be impossible to excavate.

(4) Sloped block front plate 9
The sloping block front plate 9 has a horizontal surface and an inclined surface, as shown in FIG. The horizontal plane projects at the positions of <2> and <4> shown in FIG. 5 so as to be flush with the upper surface of the block 6 and further in the cutting edge direction of the cemented carbide tip 71 (the rotation direction of the block 6 (digging direction)). Is formed. The inclined surface is formed so as to incline downward from this horizontal plane.
The inclined block front plate 9 has a function of discharging the excavated soil to the ground and can reduce the load applied to the block 6, and thus is provided as necessary.

Next, examples will be described with reference to the drawings.

<Example 1>
The excavating tool 2 of the first embodiment is shown in FIGS. 1A to 1D and FIG.
That is, the size of the bit shaft 21 is diameter: 75 mm, length: 200 mm, and the tip bit 3 of the quadrangular pyramid is provided with four cemented carbide chips 31 in a cross shape with φ=90 degrees and ψ=60 degrees. Has been. Further, the inner auxiliary bit 4 and the outer auxiliary bit 4′, which are provided at equal intervals and alternately have the notches A to D, respectively form excavation trajectories with diameters of 120 mm and 160 mm around the axis 22 of the bit shaft. Are arranged so that the upper ends of the carbide tips 41, 41 ′ at their tips are located 100 mm from the tip of the bit shaft 21. The inner auxiliary bit 4 is arranged below facing the excavated soil discharge groove 24, and the excavated soil discharge groove 24 is provided at two locations on the pyramidal surface of a quadrangular pyramid with the axis 22 of the bit axis symmetrical. Then, both side surfaces of the quadrangular pyramid are cut into a flat plate shape, and the lower part thereof is cut into a curved surface shape, and the curvature radius of the curved surface portion 25 is set to 40 mm.

Next, when an earth auger was connected to the bit shaft connection port 27 of the excavating tool 2, excavation was performed, and since the tip bit 3 precedes excavation, the excavating position is fixed. Dislocation of excavation position due to skidding did not occur. Further, since the outer auxiliary bit 4′ excavates the outer wall of the excavation hole, even if the bit shaft 21 shakes due to vibration, the inner auxiliary bit 4 does not enter the excavation track of the outer auxiliary bit 4′. Was able to continue. Then, the excavated soil passes through the excavated soil discharge groove 24 and is discharged through the outer cutout portion 43'.

<Example 2>
As shown in FIG. 7, Example 2 uses the excavating tool 1 in which the excavating tool 2 of Example 1 is combined with the enlarged diameter excavating member 5 (the diameter diameter of excavating hole is φ380) shown in FIG. 4. It was what I had.
The arrangement of the side surface bit 7 of the member 5 for diameter expansion drilling is the arrangement when the hole diameter of the diameter expansion drilling of Table 1 is "φ380", and the side surface bit 7 is closer to the bit shaft 21. The higher and the farther away, the lower the slope is, and the mortar-shaped excavation is possible. Further, each side bit 7 is arranged so as to overlap the excavation track within a range of 3 to 5 mm, and the block 6 is provided with two outer diameter bits 8 and an inclined block front plate 9.

According to the excavating tool 1 of the second embodiment, the tip bit 3, the inner auxiliary bit 4, the outer auxiliary bit 4′, the side surface bit 7, and the outer diameter bit 8 are excavated in order from the small diameter to the small diameter. , There was no skidding of the excavation axis. Also, since it is possible to form a mortar-shaped excavation surface, even if the excavation axis tilts during excavation, the inclination will be immediately restored along the mortar-shaped surface and the excavation will proceed. There was no tilt caused by the tilt of the excavation axis. Further, the excavated soil was easily discharged from the excavated soil discharge groove 24 to the ground through the inclined block front plate 9.

In addition, according to the excavating tool 1 of the second embodiment, as is clear from its structure, the side surface bits 7 are arranged so that the excavating trajectories (trajectories) overlap each other in the range of 3 to 5 mm, and therefore, the cemented carbide It was possible to suppress the abrasion of the chip 71. Further, according to the second embodiment, excavation of various diameters can be made compact by combining one excavation tool 2 and several types of diameter-enlarged excavation members 5 selected according to the excavation diameter. Therefore, unlike the prior art, it is not necessary to prepare various types of excavating tools of various sizes according to the excavation diameter each time. Therefore, there are advantages that the number of types of excavating tools to be prepared is small and the cost is low, and that even a small excavating tool that can be mounted on a building column vehicle can excavate hard rock.

<Example 3>
The third embodiment uses the excavating tool 1 in which the excavating tool 2 of the other embodiment shown in FIG. 3 is combined with the expanded diameter excavating member 5 used in the second embodiment. In the drilling tool 2 shown in FIG. 3, four cemented carbide tips 31 of the tip bit 3 are arranged in a cross shape, and the inner cemented carbide is formed from all of the pyramidal surfaces 23 at the tip of the bit shaft along the axis 22 of the bit shaft. The excavated soil discharge groove 24 is provided over a length that does not reach the upper ends of the tip 41 and the outer upper tip 41'.

The excavated soil discharge groove 24 has a width of 25 mm, a length of 55 mm, and a shape of 20 mm at the deepest depth. The groove is smoothly connected to the outer peripheral portion of the bit shaft via the curved surface 25. The other points of the excavating tool 2 of FIG. 3 are the same as those of the excavating tool 2 of the first embodiment. When excavation was performed using the excavating tool 1 of Example 3, it was confirmed that the same effect as that of Example 2 was exhibited.

<Examples 4 to 8>
Examples 4 to 8 relate to a drilling tool 1 in which a diameter-expanding drilling member 5 whose front view and plan view are shown in FIGS. 8A to 12B are combined with the drilling tool 2 of Example 1. .. Specifically, in Examples 4 to 8, the number of side surface bits 7 shown in “φ450 (No. 1)” of Table 1 is arranged, whether or not the side surface bits 7 are inclined, and the outer diameter bit 8 is formed. It is an example corresponding to the embodiment depending on the presence/absence and the presence/absence of the inclined block front plate 9, and the correspondence relationship of the embodiment is as shown in Table 2.

In any of Examples 4 to 8, even when excavating in combination with the small-sized excavating tool 2 of Example 1, the same effects as those of Examples 2 and 3 were exhibited, and therefore, they were mounted on a building column vehicle. It was confirmed that even a small drilling tool that can be used is applicable to drilling hard rock.

1, 2 Excavation Tool 21 Bit Shaft 22 Bit Shaft Center 23 Triangular Pyramid Surface 24 Excavation Soil Discharge Groove 25 Curved Surface 26 Bit Shaft Base 27 Bit Shaft Connection Port (Bolt Hole)
28 Bolt 29 Block Mounting Surface 3 Tip Bit 31 Carbide Tip (For Tip Bit)
4 Inner Auxiliary Bit 4'Outer Auxiliary Bit 41 Inner Carbide Tip 41' Outer Carbide Tip 42 Inner Fixing Base 42' Outer Fixing Base 43 Inner Notch 43' Outer Notch 5 Expanding Diameter Excavation Member 6 Block 61 Non Through hole 62 Block shaft connection port (bolt hole)
63 Block Shaft Connecting Hole 64 Block Shaft 7 Side Bit 71 Carbide Tip (for Side Bit)
8 Outer diameter bit (provided on the block)
81 Carbide Tip (for Outer Diameter Bit (provided on block))
8'outer diameter bit (provided on inclined block front plate)
81' Carbide Tip (for Outer Diameter Bit (provided on inclined block front plate))
9 Block front plate with inclined surface 10 Excavation trajectory (trajectory)
A notch A
B cutout B
C notch C
D cutout D
P Left side P'Left side lower end position Q Right side Q'Right side lower end position

Claims (13)

A drilling tool having a bit shaft, a tip bit having a carbide tip provided at the tip of the bit shaft, and an auxiliary bit provided at a lower position apart from the tip bit, the tip comprising: The bit has the shape of a pyramid whose tip is the side of the cemented carbide tip, and the triangular pyramid surface forming the pyramid has an excavated soil discharge groove for discharging excavated soil, and the auxiliary bit, A tool for excavation, comprising an inner auxiliary bit and an outer auxiliary bit which are alternately provided at equal intervals on the outer periphery of the bit shaft. The excavating tool according to claim 1, wherein the pyramid of the tip bit is one of a quadrangular pyramid and an octagonal pyramid. The excavation tool according to claim 1 or 2, wherein the excavated soil discharge groove is provided on at least one pair of opposing surfaces of the pyramidal surface, and has a curved shape toward the lower side of the bit shaft. .. The excavating tool according to any one of claims 1 to 3, wherein the excavated soil discharging groove is two to four. The inner auxiliary bit and the outer auxiliary bit are provided in a cross shape in the cross direction of the bit shaft, and a cemented carbide tip is attached to the tip thereof, according to any one of claims 1 to 4. Excavation tool as described. The said inner auxiliary bit is arrange|positioned so that the excavation track of the cemented carbide tip may be inside the excavation track of the cemented carbide tip of the said outer auxiliary bit. Drilling tools. The excavating tool according to any one of claims 1 to 6, wherein the inner auxiliary bit is disposed below the excavated soil discharge groove. It is a drilling tool which combines the drilling tool in any one of Claim 1 thru|or 7 with the diameter expansion drilling member, Comprising: The said diameter expansion drilling member is a block which is a mount, and rotation of this block. A drilling tool having a plurality of side surface bits attached to a front surface or both front and rear surfaces in a direction, and a cemented carbide tip attached to a tip of the side bit. The excavating tool according to claim 8, wherein the diameter-expanding excavating member includes an inclined block front plate having an inclined surface attached to a front surface in the rotation direction of the block. The enlarged diameter excavation member has an outer diameter bit attached to the outside of the left and right ends of the block, or the outside of the left and right ends of the block and the outside of the inclined block front plate. The drilling tool according to claim 8 or 9, wherein a carbide tip is attached to the tip of the diameter bit. The excavating tool according to any one of claims 8 to 10, wherein a plurality of the side bits are arranged on both left and right sides of the block while changing center radii thereof. 12. The excavating tool according to claim 11, wherein a plurality of side surface bits disposed on both left and right sides of the block are disposed so that loci in a rotation direction around the bit axis overlap each other. tool. 13. The side bit is arranged such that the vertical height of the side bit is high inside near the center of the bit axis and gradually decreases toward the outside. The drilling tool described in.

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