JP4652183B2 - Excavator and underground continuous groove excavator - Google Patents

Description

  The present invention relates to an excavating tool and an underground continuous groove excavating apparatus for excavating a continuous groove in the ground.

Conventionally, a trencher type excavator having a chain cutter for excavating a continuous groove in the ground is known. In a chain cutter of this type of excavator, for example, as disclosed in Patent Document 1, a bit plate is attached to a chain link, and a bit for excavation is attached to the bit plate. Then, by rotating the chain cutter, a natural groove can be excavated with a bit to form a continuous groove.
JP 2003-301477 A

  By the way, when excavating, the bit excavates while maintaining a posture corresponding to the load received from the ground to be excavated. At this time, since the cutting edge of the bit easily bites into the natural ground, the continuous groove can be excavated at an economical excavation speed. However, when excavating rocks and other high-strength grounds with the drilling device, the cutting edge of the bit becomes difficult to bite into the ground and the drilling speed decreases, and the continuous groove is drilled at an economical drilling speed. There is a problem that it cannot be done. In this case, the wear of the bit becomes severe.

  Then, this invention is made | formed in view of this point, The place made into the objective is to provide an excavation tool suitable for a natural strength excavation with high intensity | strength.

  In order to achieve the above-mentioned object, the present inventor has paid attention to the fact that a natural mountain is liable to collapse when a natural crack is generated. That is, if a crack can be efficiently generated in a natural ground with a bit, it is considered that ground excavation can be performed on a hard natural ground without lowering the excavation speed.

  Therefore, the present invention presupposes an excavator used for a chain cutter of an underground continuous groove excavating apparatus for excavating the ground to create a continuous groove, and a base having a structure that can be attached to the chain link of the chain cutter, A rotating bit provided with a blade portion having a pointed shape when viewed in the circumferential direction at an outer peripheral end, and a bit attaching means for attaching the rotating bit to the base so as to be rotatable about an axis along the excavation width direction. It is characterized by having.

  In this configuration, since the rotating bit is arranged so as to be rotatable around an axis along the excavation width direction, a streak-like groove is formed in the ground by the rotating bit, and a crack caused by this streak-like groove is ground. It can be easily generated in a mountain. And since it can excavate in the state where the strength of the natural ground was reduced by generation | occurrence | production of this crack, the fall of excavation speed can be suppressed. In addition, since the rotating bit is rotatable, the load received from the natural ground by the rotating bit rotating can be released, and the durability of the excavator can be suppressed from being lowered.

  Here, as a specific structure, the bit mounting means may include a support member that has a shaft support portion that supports the rotating bit and is configured to be detachable from the base. In this configuration, the rotating bit can be replaced by removing the support member from the base. As a result, when the blade is worn or damaged, only the rotating bit can be replaced, which is economical.

  The rotating bit may be arranged at a central portion of the base in the excavation width direction. In this configuration, since a crack can be induced at the center in the excavation width direction, the entire ground of the excavation width can be easily broken. Further, since the crack is generated at one place in the excavation width direction, the crack is easily generated.

  The rotating bits may be arranged on both sides of the base in the excavation width direction, respectively. In this configuration, since the load applied to each rotating bit can be reduced, wear of each rotating bit can be suppressed and the life can be extended.

The rotating bit may be arranged in a posture capable of rotating around an axis extending in a direction parallel to the excavation width direction, and may be supported at both ends in the axial direction by the shaft support portion. In this configuration, since the rotating bit is supported at both ends by the shaft extending in the direction orthogonal to the excavation direction, the load applied to the bearing portion can be made uniform, the support rigidity of the rotating bit can be improved, and the excavation capability can be improved. . Thereby, a continuous groove | channel can be efficiently created also in a hard ground.

  The rotating bit may be disposed on the outer side in the excavation width direction than the base. In this configuration, the corner of the natural ground can be broken ahead and the excavation efficiency can be improved. In addition, since the rotating bit protrudes outward in the excavation width direction from the base, it is possible to prevent the base from coming into contact with the ground and wear, and to increase the excavation speed.

  In this case, the rotating bit may be arranged in a posture capable of rotating around an axis extending in a direction inclined with respect to the excavation width direction. In this configuration, compared to the case where the axis of the rotating bit is parallel to the excavation width direction, the blade portion can be positioned on the outer side in the excavation width direction, so that the excavation width can be increased.

  If a plurality of the blade portions are arranged at intervals in the circumferential direction of the rotating bit, the manufacturing cost of the rotating bit can be reduced compared to a configuration in which the blade portion is formed over the entire circumference of the rotating bit. it can.

  Further, the present invention uses the excavator for the chain cutter on the premise of an underground continuous groove excavating apparatus that includes a chain cutter and circulates the chain cutter to create a continuous groove by excavating the ground. It can be configured.

  In this case, an excavation base on which an excavation bit is mounted is attached to the chain link of the chain cutter, and the blade portion of the excavation bit is closer to the ground than the blade portion of the rotating bit. It is preferable to be mounted on the excavation base in a retracted state. In this configuration, the excavation bit can be excavated with the rotary bit while the crack is effectively generated in the natural mountain, so that excavation efficiency can be improved.

  The base is provided with a support portion to which the support member can be attached, the excavation base is provided with a support portion to which the excavation bit can be attached, and both the support portions are shared. It is good also as composition which has. In this configuration, the support and the excavation base can be made versatile by sharing the support portion, and the rotation bit and the excavation bit can be appropriately arranged according to the characteristics of the natural ground. become able to.

The present invention also relates to a bit attached to an excavating tool for a chain cutter of an underground continuous groove excavator, the bit body having a shaft hole formed therethrough, and attached to an outer peripheral end of the bit body. A blade portion having a pointed shape when viewed in the direction, and is attached to the excavator so as to be rotatable about an axis along the excavation width direction, and the blade portion projects toward the excavation surface in this state; Is a rotating bit.

  As described above, according to the present invention, since the rotating bit is arranged so as to be rotatable about the axis along the excavation width direction, it is possible to suppress the excavation speed from being reduced even in high-strength excavation. It is possible to suppress the decrease in durability of the excavator.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, the underground continuous groove excavating apparatus 1 according to the embodiment of the present invention includes a crawler type traveling carriage 2, and the traveling carriage 2 extends vertically downward and can be raised and lowered. A post 3 is attached. The cutter post 3 includes an endless chain cutter 4. The chain cutter 4 is wound around sprockets (not shown) and idlers (not shown) provided at the upper and lower ends of the cutter post 3, and is configured to be driven by a hydraulic motor with a reduction gear (not shown). ing. FIG. 1 shows a state in which a continuous groove is excavated. This continuous groove is formed by sequentially excavating the ground by the horizontal traveling of the traveling carriage 2 and the vertical traveling of the chain cutter 4. It is.

  FIG. 2 shows a chain unit 5 as one unit constituting the chain cutter 4. One chain cutter 4 is configured by connecting a large number of chain units 5. As shown in FIGS. 2A and 2B, the chain unit 5 is configured by attaching the first to third excavation tool groups 10, 20, and 30 to the chain link 6.

  The first excavation tool group 10 includes a plurality (four in the illustrated example) of first excavation tools 11,. Each first excavation tool 11 includes a first bit plate 13 as a excavation base and a first bit 14 as an excavation bit. In the illustrated first excavation tool group 10, four first bit plates 13 are provided, and each of the first bit plates 13 is disposed at equal intervals with the interval holding plate 8 interposed therebetween. .

  The first bit plate 13 is provided with a support portion 16 for fixing the first bit 14 while positioning it. The support portions 16 are provided at both end portions of each first bit plate 13 so that the first bits 14 can be attached to the respective support portions 16. A plurality of (four in the illustrated example) engagement grooves 16a are formed on the upper surface of each support portion 16 at intervals in the excavation width direction, and the first bit 14 is formed in the engagement groove 16a. It can be installed accordingly.

  The second excavation tool group 20 includes a plurality of (two in the illustrated example) second excavation tools 21 and 21. Each of the second excavating tools 21 includes a bit plate (second bit plate) 23 as a base for excavation and a second bit 24 as a bit for excavation. Each of the second bit plates 23 is disposed on both sides of the first excavation tool group 10 with the spacing plate 8 interposed between the second bit plate 23 and the first excavation tool group 10.

  Each second bit plate 23 includes a plate main body formed in a rectangular flat plate shape, and a support portion 26 for fixing the second bit 24 while positioning the second bit 24 is provided on the plate main body. . One support portion 26 is provided at the center of the first bit plate 13 so as to be between the two support portions 16 of the first bit plate 13 when viewed in the excavation direction. A plurality of (four in the illustrated example) engagement grooves 26a are formed on the upper surface of the support portion 26 at intervals in the excavation width direction, and the second bit 24 corresponds to the engagement grooves 26a. Can be installed.

  The support portion 26 of the second bit plate 23 is the same as the support portion 16 of the first bit plate 13. Therefore, the same second bit 24 and first bit 14 can be used.

  The third excavation tool group 30 includes a plurality (two in the illustrated example) of third excavation tools 31 and 31. Each of the third excavating tools 31 includes a bit plate (third bit plate) 33 as a base, a rotating bit 34, and a bit mounting means 45. Each third bit plate 33 is disposed adjacent to the end side of each second excavation tool 21. The reason why the third bit plates 33 are arranged on both sides of the second excavating tool 21 in this way is that the chain cutter 4 can circulate in both directions as well as in one direction. is there.

  The first bit 14 and the second bit 24 are arranged so that almost the entire excavation width can be excavated as shown in FIG. 3 when viewed in the rotational direction of the chain cutter 4, that is, in the moving direction of each chain unit 5. Yes. That is, the first bit 14 and the second bit 24 are disposed so as to cover almost the entire excavation width direction except for the central portion, and the rotation bit 34 is arranged at the central portion in the excavation width direction as will be described later. It is installed. Note that the second bit 24 may also be disposed at the center in the excavation width direction.

  Blade portions 14 a and 24 a having a shape extending in a specific direction are provided at the distal ends of the first bit 14 and the second bit 24. The blade portions 14a and 24a are constituted by a cemented carbide tip. The 1st bit 14 and the 2nd bit 24 are arranged in the posture where each blade part 14a and 24a extends in the excavation width direction, and each blade part 14a and 24a is approximately parallel to the excavation surface of the natural ground. As a result, the first bit 14 and the second bit 24 can excavate the natural ground.

  In the present embodiment, the first bit plate 13 and the third bit plate 33 have substantially the same configuration. Therefore, hereinafter, the configuration of the third bit plate 33 will be described in detail, and a detailed description of the first bit plate 13 will be omitted.

  As shown in FIGS. 4 and 5, each third bit plate 33 includes a flat plate body 36 that is long in the excavation width direction, and each of these plate bodies 36 is in the length direction of the chain unit 5, that is, The chain cutter 4 is attached to the chain unit 5 side by side in the rotational direction.

  The plate main body 36 is provided with support portions 37 erected at both ends in the length direction, and bolt insertion holes 39 (see FIG. 6) formed between the support portions 37. The bolt insertion hole 39 is for screwing a bolt 38 for fastening the bit plate 13 to the chain link 6.

  Each support portion 37 is formed so as to extend from the longitudinal end portion of the plate body 36 toward the center portion. That is, each support portion 37 has a shape extending in the excavation width direction.

  As shown in FIG. 6, each support portion 37 includes a leg portion 41 erected on the upper surface of the plate body 36 which is a surface on the outer peripheral side of the chain cutter 4 and faces the excavation surface, and the leg portion. The guide part 43 provided at the upper end of 41 is provided, and the cross section is formed in T shape. On the upper surface of the guide portion 43, a plurality of (three in the illustrated example) engagement grooves 43a arranged at intervals in the excavation width direction are provided. The engagement groove 43a is formed in a semicircular cross section having the same inner diameter as that of a pin hole 46b described later. As shown in FIGS. 2A and 3, the first bit plate 13 is provided with four engagement grooves 16a. The first bit plate 13 and the third bit plate 33 are connected to each other. Only the number of joint grooves 16a and 43a is different. By matching the number of engaging grooves 16 a of the first bit plate 13 with that of the third bit plate 33, both the bit plates 13 and 33 can be shared.

  The bit attachment means 45 of the third excavation tool 31 includes a support member 46 configured to be detachable from the support portion 37 of the third bit plate 33. The support members 46 are respectively attached to the support portions 37, and both ends of the shaft member 50 are supported by the support members 46 (see FIG. 4). The shaft member 50 spans between the support members 46 and supports the rotating bit 34 so as to be rotatable.

  A guide groove 46 a having a T-shaped cross section is formed on the lower end surface of the support member 46. The guide groove 46 a is provided over the entire pair of opposing surfaces, and the guide groove 46 a is configured to be able to pass through the support portion 37. Thereby, the support member 46 is configured to be detachable from the plate body 36.

  A pin hole 46 b is formed in the support member 46. The pin hole 46b passes through the support member 46 in a direction perpendicular to the guide groove 46a. The pin hole 46 b is arranged such that the pin 49 inserted through the pin hole 46 b is inserted through the engagement groove 43 a of the support portion 37. The support member 46 is attached to the support portion 37, and the pin 49 is inserted into the pin hole 46b so that the support member 46 is positioned and prevented from coming off.

  The bit attachment means 45 is provided with a detent means 52 for the shaft member 50. The anti-rotation means 52 is for preventing the shaft member 50 from rotating about its axis, and includes a prismatic shaft end portion 52a provided at the end of the shaft member 50, and the shaft end portion 52a. And a shaft hole 52b having a rectangular cross section. As shown in FIG. 7, the shaft hole 52 b is formed across the support member 46 and the guide portion 43. That is, the shaft hole 52 b includes a square groove 52 c on the support member 46 side that is formed above the guide groove 46 a on one end surface of the support member 46, and a square groove on the guide portion 43 side that is formed on one end portion of the guide portion 43. 52d is formed together. The square groove 52 c of the support member 46 constitutes a shaft support portion that supports the rotating bit 34. Note that the shaft hole 52b may be formed by a square hole provided in the support member 46 instead of the structure formed by combining the two corner grooves 52c and 52d.

  As shown in FIGS. 4 and 5, the rotating bit 34 includes a bit body 55 and a blade portion 57 attached to the outer peripheral end of the bit body 55. The bit body 55 is integrally provided with a cylindrical boss portion 55b protruding in the axial direction, and a shaft hole 55c through which the shaft member 50 is inserted penetrates the bit body 55 including the boss portion 55b. Is formed. Bearing members 59 are fitted into both ends of the shaft hole 55c, and the shaft member 50 is inserted into the bearing members 59, so that the rotating bit 34 can be rotated with respect to the shaft member 50. Yes.

  The shaft member 50 is supported at both ends by inserting both ends of the shaft member 50 into the shaft hole 52b. Then, sleeves 61 are fitted on the shaft member 50 on both sides of the rotating bit 34. Since the sleeve 61 is interposed between the support member 46 and the rotating bit 34, the rotating bit 34 is positioned and arranged at the center of the third bit plate 33.

  The blade portion 57 has a pointed shape when viewed in the circumferential direction. By inserting the rotating bit 34 into the shaft member 50 disposed so as to extend in the excavation width direction, the blade portion 57 protrudes toward the excavation surface. And as shown in FIG. 3, the blade part 57 of the rotation bit 34 is arrange | positioned so that it may protrude toward the excavation surface rather than the blade parts 14a and 24a of the 1st bit 14 and the 2nd bit 24. As shown in FIG. In other words, the blade portions 14 a and 24 a of the first bit 14 and the second bit 24 are in a state of being retracted from the natural ground than the blade portion 57 of the rotating bit 34.

  The blade portion 57 is made of a cemented carbide tip, and as shown in FIG. 8, a plurality of blade portions 57 are arranged at intervals in the rotation direction. The blade portion 57 is attached to the bit body 55 so as to protrude radially outward from the bit body 55.

  In the underground continuous groove excavating apparatus 1 according to the present embodiment, the chain cutter 4 circulates in, for example, the direction indicated by the arrow in FIG. 1 while the traveling carriage 2 moves in the direction indicated by the arrow in FIG. Create a groove. At the time of this construction, the ground bit having a width corresponding to the width of the chain cutter 4 is excavated by the first bit 14 and the second bit 24 as the chain cutter 4 rotates. A streak-like groove is formed at the center in the excavation width direction, and a crack caused by this streak-like groove can be easily generated in the natural ground. And since it can excavate in the state where the strength of the natural ground was reduced by generation | occurrence | production of this crack, the fall of excavation speed can be suppressed. In addition, since the rotating bit 34 is rotatable, the rotating bit 34 can release the load received from the natural ground by rotating, and the durability of the excavating tool can be prevented from being lowered.

  Furthermore, in this embodiment, since it is set as the structure which arrange | positions the rotation bit 34 only in the center part of the excavation width direction, it becomes the structure which is easy to induce a crack. Moreover, since the shaft member 50 that supports the rotating bit 34 has a both-ends support structure, the supporting rigidity of the rotating bit 34 can be improved, which contributes to the improvement of the excavation ability. Thereby, a continuous groove | channel can be efficiently created also in a hard ground.

  And in this embodiment, since it is set as the arrangement structure which the rotation bit 34 protruded toward the excavation surface rather than the 1st bit 14 and the 2nd bit 24, generating a crack in a natural ground with the rotation bit 34, The natural bit can be excavated by the first bit 14 and the second bit 24, and the excavation efficiency can be improved.

  In the present embodiment, since the blade portions 57 of the rotating bit 34 are arranged at intervals in the circumferential direction, the rotating bit is compared with the configuration in which the blade portion is formed over the entire circumference of the rotating bit 34. The manufacturing cost of 34 can be reduced.

  In the present embodiment, since the support member 46 that supports the rotating bit 34 is configured to be detachable from the third bit plate 33, only the rotating bit 34 is attached when the blade portion 57 is worn or damaged. It can be exchanged and is economical.

  Moreover, in this embodiment, the support part 16 of the 1st excavation tool 11 and the support part 37 of the 3rd excavation tool 31 can be shared, and the bit plates 13 and 33 can have versatility, and the third bit Since the excavating bit (first bit 14 and second bit 24) can be attached to the plate 33 and the rotating bit 34 can be attached to the first bit plate 13, the bit plate is used to attach the rotating bit 34 and the excavating bit. 13 and 33 need not be replaced, and the rotation bit 34 and the excavation bit can be appropriately arranged according to the characteristics of the natural ground.

  In the present embodiment, one rotating bit 34 is arranged at the center of each third bit plate 33. Instead, the rotating bit 34 is shown in FIGS. As such, a configuration may be adopted in which two are arranged on each third bit plate 33. In this configuration, in addition to the support portions 37 at both ends in the length direction of the plate main body 36, support portions 37A are also formed in the center portion in the length direction. A shaft member 50 is bridged between the support portion 37 at one end and the support portion 37A at the central portion, and another shaft member is provided between the support portion 37 at the other end portion and the support portion 37A at the central portion. 50 is spanned, and the rotation bit 34 is rotatably supported on each shaft member 50. By setting it as such a structure, each rotation bit 34 will be arrange | positioned on both sides on both sides of the center part of the excavation width direction. In this case, as shown in FIG. 11, the rotating bit 34 may have a configuration in which the boss portion 55 b is not provided in the bit body 55. According to this configuration, since the load applied to each rotating bit 34 can be reduced, wear of each rotating bit 34 can be suppressed, and the life can be extended.

  Moreover, as a structure by which the rotation bit 34 is arrange | positioned at both sides, as shown in FIG.12 and FIG.13, it can also be set as the arrangement | positioning which the rotation bit 34 protruded to the outer side of the excavation width direction rather than the 3rd bit plate 33. In this configuration, the guide groove 46a of the support member 46 is configured to extend from one end surface to an intermediate portion between the opposing surfaces instead of being provided over the entire pair of opposing surfaces, and the shaft member 50 can be inserted. A simple shaft hole 52 b is formed on the other end surface of the support member 46. The shaft member 50 is inserted into the shaft hole 52b of the support member 46 from the outside in the excavation width direction. A head 50a having a diameter enlarged in a flange shape is provided at the distal end of the shaft member 50, while a retaining pin inserted through the support member 46 at the proximal end of the shaft member 50 inserted through the shaft hole 52b. The pin hole 50b for inserting the is formed. This pin has a function of preventing the shaft member 50 from coming off and a function of preventing the shaft member 50 from rotating. According to this structure, the corner of a natural ground can be made to break ahead and excavation efficiency can be improved. Moreover, since the rotating bit 34 protrudes outward in the excavation width direction from the third bit plate 33, the third bit plate 33 can be prevented from being in contact with the ground and worn, and the excavation speed can be increased. be able to.

  In this configuration, the guide portion 43 of the third bit plate 33 may be configured to be parallel to the plate body 36 or may be inclined with respect to the plate body 36 as shown in FIG. By inclining the guide portion 43, the blade portion 57 of the rotary bit 34 facing the excavation surface can be configured to face outward in the excavation width direction. Therefore, the blade portion 57 is disposed on the outer side by inclining the guide portion 43. And the excavation width can be made wider.

  Further, in the present embodiment, the configuration in which the blade portion 57 is arranged at the central portion in the thickness direction of the rotating bit 34 is shown, but instead, the blade portion 57 has a thickness of the rotating bit 34 as shown in FIG. It is good also as a structure biased and arrange | positioned at the end of a direction. In this configuration, the blade portion 57 can be further arranged outside in the excavation width direction.

  Further, in the present embodiment, the rotation preventing means 52 is configured by forming the shaft end portion 52a in a prismatic shape and forming the shaft hole 52b by a square hole, but instead, as shown in FIG. The shaft end portion 52a of the shaft member 50 may be formed in a cylindrical shape, and a pin hole 52e for inserting a pin inserted through the through hole 46c of the support member 46 may be provided in the shaft end portion 52a.

  Further, as shown in FIG. 16, the shaft end portion 52a of the shaft member 50 is formed in a columnar shape without providing a detent means, and can be lubricated with respect to the shaft hole 52b formed of a round hole of the support member 46. Any configuration may be used.

It is a side view which shows roughly the whole structure of the underground continuous groove excavation apparatus which concerns on embodiment of this invention. The chain unit which comprises the chain cutter of the said underground continuous groove excavation apparatus is shown, (a) is a top view, (b) is a side view. It is the figure seen from the III-III line of FIG. 2 in the arrow direction. It is a front view which shows the 3rd excavation tool of the said underground continuous groove excavation apparatus as a partial cross section figure. It is a top view which shows the 3rd bit plate which comprises the 3rd excavation tool of FIG. It is a perspective view which shows the said 3rd bit plate, a supporting member, and a shaft member. It is sectional drawing which shows the state which the supporting member is mounted | worn with the said 3rd bit plate, and is supporting the shaft member. It is a front view which shows the structure of the rotation bit of a said 3rd excavation tool. FIG. 5 is a view corresponding to FIG. 4 and showing the configuration of another embodiment. FIG. 6 is a view corresponding to FIG. 5 showing a configuration of another embodiment. It is sectional drawing which shows the structure of the rotation bit in other embodiment. FIG. 5 is a view corresponding to FIG. 4 and showing the configuration of another embodiment. FIG. 6 is a view corresponding to FIG. 5 showing a configuration of another embodiment. It is sectional drawing which shows the structure of the rotation bit in other embodiment. It is a perspective view which shows the structure of the rotation prevention means in other embodiment. It is a perspective view which shows other embodiment which does not provide a rotation prevention means.

Explanation of symbols

4 Chain cutter 6 Chain link 13 1st bit plate (example of excavation base)
14 First bit (example of excavation bit)
14a Blade part 23 2nd bit plate (an example of a base for excavation)
24 Second bit (example of excavation bit)
24a Blade 31 Third Excavator 33 Third Bit Plate (Example of Base)
34 Rotating Bit 34a Cutting Edge 45 Bit Mounting Means 46 Support Member 50 Shaft Member

Claims (12)

An excavator used for a chain cutter of an underground continuous groove excavator that excavates the ground to create a continuous groove,
A base having a structure attachable to a chain link of the chain cutter;
A rotating bit provided with a blade having a pointed shape when viewed in the circumferential direction at the outer peripheral end,
An excavating tool comprising: a bit attaching means for attaching the rotating bit to the base so as to be rotatable about an axis along the excavation width direction.   The excavator according to claim 1, wherein the bit attachment means includes a support member that has a shaft support portion that supports the rotating bit and is configured to be detachable from the base.   The excavator according to claim 1 or 2, wherein the rotating bit is disposed at a central portion of the base in the excavation width direction.   The excavator according to claim 1 or 2, wherein the rotating bits are respectively disposed on both sides of a center portion of the base in the excavation width direction. The rotating bit, while being arranged in a rotatable posture about an axis extending in the excavation width direction parallel to the direction, in claim 2, characterized in that it is supported at both ends in the axial direction by the shaft support The drilling tool described.   The excavator according to claim 1 or 2, wherein the rotating bit is disposed outside the base in the excavation width direction.   The excavator according to claim 6, wherein the rotating bit is arranged in a posture capable of rotating around an axis extending in a direction inclined with respect to the excavation width direction. The excavator according to any one of claims 1 to 7, wherein a plurality of the blade portions are arranged at intervals in the circumferential direction of the rotating bit. An underground continuous groove excavating apparatus that includes a chain cutter and circulates the chain cutter to excavate the ground to create a continuous groove,
The excavation tool of any one of Claim 1 to 8 is used for the said chain cutter, The underground continuous groove excavation apparatus characterized by the above-mentioned. An excavation base to which an excavation bit is attached is attached to the chain link of the chain cutter,
10. The underground continuous groove excavation according to claim 9, wherein the blade portion of the excavation bit is attached to the excavation base in a state where the blade portion of the excavation bit is retracted from a natural ground than the blade portion of the rotating bit. apparatus. The base is provided with a support portion to which the support member can be attached,
The excavation base is provided with a support portion to which the excavation bit can be attached,
The underground continuous trench excavation apparatus according to claim 10, wherein the both support portions are shared. A bit attached to an excavating tool for a chain cutter of an underground continuous groove excavator,
A bit body having a shaft hole formed therethrough;
It is attached to the outer peripheral end of the bit body, and has a blade portion having a pointed shape when viewed in the circumferential direction,
A rotating bit that is attached to the excavator so as to be rotatable about an axis along the excavation width direction, and in which the blade portion is arranged to protrude toward the excavation surface.

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