JP2008179971A - Pile hole excavation head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pile hole excavation head which can visually keep the track of an excavating radius on the ground based on a shaking angle of an excavation arm by recognizing the height of a stopper receiver. <P>SOLUTION: The pile hole excavation head 50 is set up by mounting the excavation arm 30 having a stopper 35 arranged on the upper edge thereof so as to be shakable on a horizontal shaft 27 of a head body 1. Then the stopper receiver 27 having a first holding notch 20 and a second holding notch 22 is ascendably and descendably mounted to an elevation shaft 10 of the head body 1. During the forward rotation of the excavation rod 50, the first holding notch 20 is engaged with the stopper 35 at a descended location of the stopper receiver 17, and the excavation arm 30 carries out excavation in the range of a small radius D<SB>1</SB>(a). On the other hand during backward rotation, the second holding notch 22 is engaged with the stopper 35 at an ascended location, and the excavation is carried out in the range of a large radius D<SB>2</SB>(b). Thus based on a mark line 29 of an operation rod 28 mounted to the stopper receiver 27, a difference H<SB>0</SB>between the ascended location and the descended location can be checked. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a drilling head for excavating a pile hole, and relates to a pile hole drilling head capable of excavating with different diameters, such as a shaft portion of a pile hole and an expanded bottom portion of the pile hole.

  A drilling head that rotates and drills a pile hole. Apart from a drilling blade for shaft excavation, a drilling blade for expansion drilling is prepared. A method has been adopted in which an excavation blade for excavation is moved to perform an enlarged excavation (Patent Documents 1 and 2). In this case, since the excavation head is in a pile hole filled with excavated soil or mud soil, in the case of a mechanism that expands, it is necessary to devise in order to surely open depending on the contents of the excavated soil. In the case of the hydraulic type, the apparatus is large and complicated.

  The applicant has also proposed a drilling head in which drilling arms are swingably mounted on both sides of the head body (for example, Patent Document 3). With this excavation head, the same excavation arm is used for forward rotation and reverse rotation, and shaft excavation and bottom expansion excavation are made possible. When the excavating rod connected to the excavating head was rotated forward, the excavating arm was opened at a small angle by earth pressure, and the shaft part of the pile hole was excavated. In addition, when the excavation rod was rotated in reverse, the excavation arm that had been closed once was swung to the opposite side by the earth pressure, and was swung at a large angle, and the bottom of the pile hole could be excavated. In this case, stoppers for limiting the swing angle were attached to the forward rotation side and the reverse rotation side, respectively, and the excavation diameter could be changed reliably with a simple mechanism.

  In addition, an invention has also been proposed in which a stopper is formed by changing the relative position (height and rotation angle) between an outer rod and an inner rod by rotating and raising the outer rod from the ground on the inner and outer double rods (Patent Document). 4).

There is also proposed a drilling head that swings the drilling arm by the rotation of the drilling rod, and an operation rod provided at the upper end of the drilling arm that opens and closes the kneading rod in the upper pile hole (patent) Reference 5).
JP 63-184612 A JP-A-3-221697 JP-A-3-260279 JP-A-8-326457 7-10092

  With a drilling head using a drilling arm, it was confirmed that excavation was performed with an enlarged diameter by measuring the excavation resistance, but it was required to visually confirm that the expanded excavation was performed more reliably from the ground. It was done. In addition, if the swing angle is fixed to the enlarged diameter, the excavation head cannot be recovered on the ground, so the excavation arm can be expanded more reliably, and then the excavation arm is closed and the diameter of the excavated pile hole shaft It was required to collect the excavation head on the ground in the following manner.

However, the present invention forms a stopper on the excavating arm, forms a holding portion corresponding to the excavating diameter on the stopper receiver that can be moved up and down by a lifting operation from the ground, and associates the holding portion with the stopper. In other words, the present invention is a pile hole excavation head characterized by comprising all the following requirements.
(1) The base end portion of the excavating arm having the excavating blade at the distal end portion was swingably attached to both sides of the head main body having the connecting portion with the excavating rod at the upper end portion via a horizontal shaft.
(2) A stopper protruding upward is formed on the upper part of the base of the excavating arm.
(3) At the upper end of the head body, an elevating shaft portion is formed between the horizontal shaft and the connecting portion, and a stopper receiver having at least two holding portions is attached to the elevating shaft portion so as to be movable up and down. did.
(4) The first holding portion of the stopper receiver is configured to be able to hold a swinging swinging angle in cooperation with the stopper during excavation at the first swinging angle of the excavating arm,
The second holding portion is configured to be able to hold a swinging swinging angle in cooperation with the stopper during diameter excavation at a second swinging angle different from the first swinging angle.
(5) Elevating operation means that can visually check whether the stopper receiver is in the ascending position or the descending position from the ground is connected to the stopper receiver.

Moreover, in the above, it is a pile hole excavation head characterized by comprising all the following requirements.
(1) An operation protrusion is formed between the first holding part and the second holding part at the lower end of the stopper receiver.
(2) A first guide slope and a second guide slope on which the operation protrusion abuts are formed on the upper edge of the stopper of the excavating arm.
(3) The second rocking angle is the rocking angle for large-diameter excavation, the first rocking angle is the rocking angle for small-diameter excavation, and the first guide slope is the rocking side for small-diameter excavation. The second guide slopes were respectively formed so as to guide to the rocking side of the large-diameter excavation.

  In the above, the first height of the stopper when the first holding portion of the stopper receiver is locked to the stopper, and the second height of the stopper when the second holding portion of the stopper receiver is locked to the stopper. It is a pile hole excavation head characterized by setting the shape of the 1st holding part and the 2nd holding part so that it may become height different from height. Further, the first holding part of the stopper receiver regulates at least the maximum swing angle in cooperation with the stopper during the small-diameter excavation arm, and the second holding part during the large-diameter excavation of the excavating arm, A pile hole excavation head characterized in that the maximum swing angle and the minimum swing angle can be maintained in cooperation with the stopper.

When the excavating rod is rotated, the excavating arm swings to one side or the other side according to the rotation direction, and the stopper angle is held by the stopper receiver to maintain the preset swing angle of the one side or the other side. Pile hole excavation can be reliably performed at a predetermined excavation diameter set at one swing angle and the second swing angle. In addition, when the height of the stopper receiver is set using the first holding portion and the second holding portion, and the locking height with the stopper is set differently, for example, the excavating arm is
・ If the excavating rod is rotating forward and the stopper receiver is in the lowered position,
Drilling diameter at the first swing angle (small-diameter drilling condition, etc.)
・ If the excavation rod rotates in the reverse direction and the stopper receiver is in the lowered position,
Drilling diameter at the second swing angle (large-diameter drilling condition, etc.)
-If the excavation rod does not rotate and the stopper holder is in the raised position,
Therefore, there is an effect that the state of the excavating arm can be surely visually observed from the ground by the lifting operation means connected to the stopper receiver.

  By changing the shape of the stopper holder according to the shape of the stopper, the restriction of the maximum diameter, the restriction of the minimum shape, both restrictions, etc. can be arbitrarily set, and the optimum excavation head according to the construction method can be set There is an effect that can be configured. Therefore, for example, three different excavation diameters can be set at the time of forward rotation, and two different excavation diameters can be set at the time of reverse rotation, so that various excavation diameters can be set by combining the holding portion and the stopper.

  The pile hole excavation head 50 according to the present invention has excavation blades 34 and 34 at the front end portion thereof via the horizontal shaft 27 on both sides of the base portion 2 of the head body 1 having the connection portion 15 with the excavation rod 50 at the upper end portion. The base 31 of the excavating arms 30 and 30 is configured to be swingably mounted (FIG. 1). A stopper 35 protruding upward is formed on the upper edge of the base 31 of the excavating arm 30. An elevating shaft portion 10 is formed below the connection portion 15 at the upper end portion of the head body 1. The elevating shaft portion 10 is located above the mounting position of the horizontal shaft 27. A stopper receiver 27 having two first holding cutouts 20 (holding portions) and second holding cutouts 22 (holding portions) is attached to the lifting shaft portion 10 so as to be movable up and down. The elevating shaft portion 10 passes through the vertical center opening 24 formed in the stopper receiver 17, and the stopper receiver 17 can be moved up and down along the elevating shaft portion 10.

  The first holding notch 20 of the stopper receiver 17 is configured to be able to hold a swinging swinging angle in cooperation with the stopper 35 when the excavating arm 30 is drilled at the first swinging angle (small diameter) (FIG. 2 ( a)), the second holding notch 22 is configured to be able to hold the swinging swinging angle in cooperation with the stopper 35 during the diameter excavation at the second swinging angle (large diameter) (FIG. 2 ( b)). Here, the first swing angle and the second swing angle can be set regardless of the rotation direction of the excavation head 40 (excavation rod 50) as long as they are different as long as they are different.

Also, the height of the upper surface 17a of the stopper receiver 17 when the stopper 35 is locked to the second holding notch 22 is higher by H ₀ than when the stopper 35 is locked to the first holding notch 20. Thus, the shapes of the first holding notch 20 and the second holding notch 22 are determined. At this time, the lower end of the operating rod 28 (elevating operation means) is connected to the stopper receiver 17 so that the height difference H ₀ can be recognized from the ground, and the upper end of the operating rod 28 is exposed to the ground. Since the mark line 29 is attached to the upper end of the operation rod, the difference in the position of the stopper receiver 17 can be recognized from the ground (FIG. 2). It is also possible to raise and lower the operation rod 28 to raise and lower the stopper receiver 17.

  An embodiment of the excavation head 40 according to the present invention will be described with reference to FIGS.

[1] Configuration of the excavation head 40

  (1) The head main body 1 is formed with an elevating shaft portion 10 having an outer diameter smaller than that of the base portion 2 at the upper end 2a of the quadrangular columnar base 2 so that the axes coincide with each other. A base disk 14 having a connection portion 15 is continuously provided, and a flat bulge portion 5 is formed continuously with the lower end of the base portion 2. The base 2 has one side surfaces 3 and 3 that face each other, and other side surfaces 4 and 4 that are adjacent to the side surface 3 and face each other.

  The base 2 is set to such a size that the one side surfaces 3 and 3 approach toward the lower side (the width of both the other side surfaces 4 and 4 is reduced), and reaches the bulging portion 5 continuously from the lower end of the base portion 2. . The surface of the bulging portion 5 that is continuous with one side surface 3 of the base 2 is defined as one side surface 6, and the bulging portion 5 bulges in the horizontal direction so that the width of the one side surface 6, 6 is increased. . The lower edge 7 of the bulging portion 8 is formed in an arc along the swinging orbit of the excavating arm 30, and the fixed excavating blades 8 and 8 are attached to the lower edge 7 downward.

  A stopper receiver 17 is fitted to the elevating shaft portion 10 of the head body 1 so as to be movable up and down. The stopper receiver 17 has a quadrangular prism shape and a central opening 24 (circular shape) that can be moved up and down by inserting the operation shaft portion 10 in the center. The surface of the stopper receiver 17 corresponding to the one side surfaces 3 and 3 of the base 2 of the head body 1 is defined as one side surface 18 and 18, and the first holding notch (first holding portion) 20 is formed on the side surface 18 side of the stopper receiver 17. A second holding notch 22 is formed. The remaining portion between the holding cutouts 20 and 22 is referred to as a central protrusion 19. The edge of the first holding notch 20 on the side of the central protrusion 19 is referred to as a locking edge 21, and the edge of the second holding notch on the side of the central protrusion 19 is referred to as a locking edge 23 (FIGS. 1A and 3).

  At the upper end 2a of the base 2 of the head main body 1, guide rods 12 are provided so as not to protrude from the other side surface 4 on the other side surfaces 4 and 4 side. The guide rods 12 and 12 are formed in parallel with the operation shaft portion 10 and are inserted into the guide vertical holes 25 and 25 of the stopper receiver 17, respectively.

  Further, an operation rod 28 is attached to the upper surface 17a (or one side surface 18) of the stopper receiver 17 to operate the stopper receiver 17 from the ground to move up and down. Further, a mark line 29 is formed on the ground portion of the operating rod 28 so that the relative height of the stopper receiver 17 can be recognized (FIG. 2).

  (2) The horizontal shaft 27 protrudes from the side surfaces 3 and 3 of the base 2 of the head body 1. The horizontal axis 27 can be either an integral axis or a divided axis as long as the axes coincide with each other on the side surfaces 3 and 3. The base end portion 31 of the excavating arm 30 is attached to the horizontal shaft 27 so as to be swingable. Further, since the horizontal shaft 27 only needs to be an axis capable of rotating the excavating arm 30, the horizontal shaft 27 may be provided on the excavating arm 30 and a bearing may be provided on the head body 1 (not shown).

  (3) The excavating arm 30 has a base end portion 31 that has a large diameter around the horizontal axis 27, a middle portion 32 that has a small width, and a wide tip portion 33. The excavation arm 30 is deformed along the deformation of the surface shape of the one side surface 3, 3 of the head main body 1, and the shape change of the base 2 and the bulging portion 5 of the head main body 1 (the one side surface 3, 3 is directed downward). (Both of the excavating arms 30, 30 are formed so as to be close to each other) and bent in such a manner that the excavating arms 30, 30 approach each other. Bend away) Excavation blades 34, 34 project from the distal end portion 33 of the excavation arm 30 in a direction toward the outside (so that the distal ends of the excavation arms 30, 30 are separated).

  Further, a stopper 35 is projected from the upper end of the base 31 of the excavating arm 30 upward (that is, on the opposite side of the excavating blade 34 across the horizontal shaft 27 in the length direction of the excavating arm 30). . An edge 36 on one side of the stopper 35 can be locked with the locking edge 21 of the first holding notch 20, and an edge 36 a on the other side of the stopper 35 can be locked with the locking edge 23 of the second holding part 22. To form. Further, the distal end portion 37 of the stopper 35 is formed to have a pointed end, and a guide slope 38 is formed on the edge 36 side, and a guide slope 38a is formed on the edge 36a side (FIGS. 1A and 3).

  The excavation head 40 is configured as described above (FIGS. 1A and 1B).

[2] Use of excavation head 40

  Subsequently, the use of the excavation head 40 of the present invention will be described.

  (1) The excavation rod 50 is attached to an excavator (not shown), the connecting portion 15 of the excavation head 40 is attached to the lower end of the excavation rod 50, and the operation rod 28 is extended upward along the excavation rod 50. At this time, the operation rod 28 is appropriately added, and the tip of the operation rod 28 is positioned on the ground (not shown). Further, the operating rod is pulled, and the lower edge of the stopper receiver 17 is located below the upper end of the stopper 35 of the excavating arm.

  When the excavation rod 50 is rotated forward, the excavation arm 30 swings to one side of the arrow 42. When the operating rod 28 is lowered in this state, the stopper receiver 17 is lowered and the stopper 35 enters the first holding cutout 20. Even if the excavating arm 30 swings (in the direction of arrow 42) is small, the central protrusion 19 of the stopper receiver 17 hits the guide slope 38 of the stopper 35 of the excavating arm 30, and the stopper 35 is the first holding notch. The stopper 35 can be securely held by entering the inside 20.

If the operating rod 28 is lowered as it is, the stopper 35 enters the first holding notch 20, and the edge 36 is locked to the locking edge 21. Further, since the other guide inclined surface 38a is engaged with the holding engagement edge 21a of the first holding notch 20, the stopper 35 is held by the first holding notch 20 of the stopper receiver 17, and the swing angle is maintained. . Therefore, the pile hole shaft portion 45 is excavated with a predetermined excavation diameter (D ₁ ) (FIG. 2A).

Accordingly, the drill rod 50 in the forward rotation state, on the ground, that if it is confirmed that the operating rod 28 (marker line 29) is lowered, the pile hole shaft 45 at a predetermined drilling diameter D ₁ is drilled Can be confirmed.

  If there is an underground fault or the like during excavation, once the operation rod 28 is pulled up and the stopper receiver 17 is raised by an operation from the ground, the first holding notch 20 and the stopper 35 are locked. Since it is canceled, appropriate measures can be taken. If the operation rod 28 is then lowered while the excavation rod 50 is rotated forward, the stopper 35 is accommodated in the first holding cutout 20 of the stopper receiver 17 and can be excavated with a predetermined excavation diameter.

(2) If the pile hole shaft portion 44 is excavated to a predetermined depth (with the formation depth of the root consolidation portion), the rotation of the excavating rod 50 is stopped, and the operation rod 28 is pulled upward, the stopper receiver 17 is raised. Thus, the excavating arm 30 can swing freely. In this state, if the excavating rod 50 is rotated in the reverse direction, the excavating arm 30 is swung in the direction indicated by the arrow 43 due to earth pressure generated on the excavating blade 34 or the like. Therefore, when the operating rod 28 is lowered, the stopper receiver 17 is lowered and the stopper 35 enters the second holding notch 22, and the edge 36 a is locked to the locking edge 23. In addition, since the guide slope 38 on the other side of the stopper 35 is locked to the holding locking edge 23a of the second holding notch 22, the stopper 35 is held by the second holding notch 22 of the stopper receiver 17, and the swing angle is increased. Maintained. Therefore, the pile hole widening portion is excavated with a predetermined excavation diameter (D ₂ ) (FIG. 2B).

  Even if the excavation arm 30 swings in the direction indicated by the arrow 43 in a small amount, the central protrusion 19 of the stopper receiver 17 hits the guide slope 38a of the stopper 35 of the excavation arm 30, and the stopper 35 is in the second holding notch 22. The stopper 35 can be securely held inside.

Thus, while the reverse rotation of the drill rod 50, on the ground that if it is confirmed that the operating rod 28 (marker line 29) is lowered, the Kuiana拡底unit 46 at a predetermined drilling diameter D ₂ has been drilled I can confirm.

At this time, when the stopper 35 is locked to the second holding notch 22 from the upper surface height 17a of the stopper receiver 17 when the stopper 35 is locked to the first holding notch 20 (FIG. 2A). since more of the stopper receiving 17 of the upper surface height 17a (FIG. 2 (b) is is formed to be higher by H _0, if confirmed mark line 29 on the ground, the stopper 35 is engaged with the first holding notches 20 It can be recognized whether it is stopped or locked to the second holding notch 22 (FIGS. 2 (a) and 2 (b)). It can also be formed higher than the state in which it is locked to the holding notch 22 (not shown), and the difference is that the height H ₀ differs depending on the locking position of the first holding notch 20 or the second holding notch 22. As long as this occurs.

  Cement milk is discharged from the cement milk discharge port of the excavation head 40 and stirred in the root consolidation part 45 to form a root consolidation layer, and the excavation head 40 is pulled up to the ground.

  When the excavation of the predetermined pile hole widening portion 46 is completed, if the excavation rod 50 is stopped and the operation rod 28 is pulled from the ground, the stopper receiver 17 rises to release the holding of the stopper 35 and excavate. The arm 30 is in a state of hanging downward (a state in which the arm 30 can freely swing) (FIG. 1A). If the excavating rod 50 is not rotated and the operating rod 28 is in the raised state, it can be confirmed from the ground that the excavating arm 30 is in a suspended state.

  (3) As described above, the excavating arm 30 is in the swing range (first position) during small-diameter excavation (FIG. 2 (a)) or in the swing range (second position) during large-diameter excavation. Whether it is (FIG. 2 (b) or in a state of hanging down (FIG. 1 (a)) is determined by checking the direction of rotation of the excavating rod 50 and whether the operating rod 28 is in the up or down state. Therefore, by grasping the state of the operation rod 28 on the ground, the state of the excavating arm 30 can be recognized more reliably.

[3] Other embodiments

  In the above embodiment, the stopper receiver 17 is moved up and down by one operating rod 28. However, if the stopper receiver 17 can be moved up and down in a pile hole filled with excavated soil, a combination of a plurality of wires, etc. These means can also be used (not shown).

  In the above-described embodiment, the operation rod 28 is exposed, but can be accommodated in the excavation rod 50 so as to be movable up and down (not shown).

  In the above-described embodiment, as the means for confirming the height of the mark rod 29 on the operating rod 28, a lifting operation means such as a rod or a wire for raising and lowering the stopper receiver 27 can be used in addition to the operating rod 28 (FIG. Not shown).

  In the above embodiment, the display rod corresponding to the mark line 29 is formed on the excavation rod 50 so that the operation rod 28 corresponds to the mark line 29 so that the relative position (depth) of the mark line 29 can be confirmed on the ground by visual observation or the like. (Not shown). If the sensor corresponding to the position (depth) of the mark line 29 is provided corresponding to the display gauge of the excavation rod 50, the position of the mark line 29 can be confirmed electrically (not shown).

  Moreover, in the said Example, although the outer cross section of the raising / lowering axial part 10 was formed circularly, it can also be set as other cross-sectional shapes, such as square shape (not shown). In this case, the stopper receiver 17 is also formed in a shape that can be fitted and raised and lowered. In the case of a shape other than circular, since the stopper receiver 17 does not rotate with respect to the excavating arm 30 (stopper 35), the guide rod 12 and the guide vertical hole 25 are unnecessary.

  In the embodiment, the shape of the stopper 35 is not limited to the illustrated shape as long as the swing angle of the excavating arm 30 can be regulated in cooperation with the first and second holding cutouts 20 and 22.

In the above embodiment, the stopper holder 17 is provided with the first holding notch 20 during forward rotation and the second holding notch 22 during reverse rotation.
-One, two, or three or more holding notches can be set only during forward rotation (not shown). Thereby, it can also be set as a different excavation angle also in the same rotation direction.

    -Two or more holding cutouts can be set during forward rotation and two or more holding cutouts during reverse rotation, and four or more different excavation angles can be set (not shown).

Therefore, in these cases, a single excavation head can excavate pile holes having a plurality of excavation diameters set in advance by using one excavation head. Further, in these cases, when the shape of the holding notch is set so that the height of the stopper receiver 17 is different when the stopper is locked to each holding notch, the locked state can be easily recognized from the ground.

  In the embodiment, a conventional stopper for forming a protrusion on the head main body 1 can be used together (not shown).

  Moreover, in the said Example, a stirring blade can be formed in the other side surfaces 4 and 4 of the base 2 of the head main body 1, and it can also comprise so that excavation soil may be conveyed upwards, crushing and stirring (illustrating). Absent).

In the embodiment of the present invention, (a) is a front view and (b) is a left side view. Similarly, in the front view of the embodiment, (a) represents a small diameter excavation, and (b) represents a large diameter excavation. It is an enlarged front view showing the structure of a stopper receptacle and a stopper.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Head main body 2 Base part 3 of head main body One side surface 4 of base part of head main body Other side surface 5 of head main body bulging part 8 Head body fixed excavation blade 10 Head body raising / lowering shaft part 15 Connection part 17 Head Stopper receiver 17a Upper surface 19 of the stopper receiver Center protrusion 20 of the stopper receiver First holding notch 21 of the stopper receiver Locking edge 21a of the first holding notch of the stopper receiver Holding edge 22 of the first holding notch of the stopper receiver Stopper Second holding cutout 23 of the receiving stopper Locking edge 23a of the second holding cutout of the stopper receiver Pressing holding edge 24 of the second holding cutout of the stopper receiver Central opening 27 of the stopper receiver Horizontal shaft 28 Operating rod (elevating operation means)
30 Excavation Arm 34 Excavation Arm Excavation Blade 35 Excavation Arm Stopper 36, 36a Stopper Edge 38, 38a Guide Slope 40 Excavation Head 45 Pile Hole Shaft 46 Pile Hole Widening 50 Excavation Rod

Claims (4)

A pile hole excavation head characterized by comprising all the following requirements.
(1) The base end portion of the excavating arm having the excavating blade at the distal end portion was swingably attached to both sides of the head main body having the connecting portion with the excavating rod at the upper end portion via a horizontal shaft.
(2) A stopper protruding upward is formed on the upper part of the base of the excavating arm.
(3) At the upper end of the head body, an elevating shaft portion is formed between the horizontal shaft and the connecting portion, and a stopper receiver having at least two holding portions is attached to the elevating shaft portion so as to be movable up and down. did.
(4) The first holding portion of the stopper receiver is configured to be able to hold a swinging swinging angle in cooperation with the stopper during excavation at the first swinging angle of the excavating arm,
The second holding portion is configured to be able to hold a swinging swinging angle in cooperation with the stopper during diameter excavation at a second swinging angle different from the first swinging angle.
(5) Elevating operation means that can visually check whether the stopper receiver is in the ascending position or the descending position from the ground is connected to the stopper receiver. The pile hole excavation head according to claim 1, comprising all the following requirements.
(1) An operation protrusion is formed between the first holding part and the second holding part at the lower end of the stopper receiver.
(2) A first guide slope and a second guide slope on which the operation protrusion abuts are formed on the upper edge of the stopper of the excavating arm.
(3) The second rocking angle is the rocking angle for large-diameter excavation, the first rocking angle is the rocking angle for small-diameter excavation, and the first guide slope is the rocking side for small-diameter excavation. The second guide slopes were respectively formed so as to guide to the rocking side of the large-diameter excavation. The first height of the stopper when the first holding portion of the stopper receiver is locked to the stopper is different from the second height of the stopper when the second holding portion of the stopper receiver is locked to the stopper. The pile hole excavation head according to claim 1, wherein the shapes of the first holding part and the second holding part are set so as to be. The first holding portion of the stopper receiver regulates at least the maximum swing angle in cooperation with the stopper when excavating the small diameter of the excavating arm,
The second holding portion is configured to be able to hold a maximum swing angle and a minimum swing angle in cooperation with the stopper when excavating a large diameter of the excavating arm. Pile hole drilling head.

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