JP2004183378A - Blades for steel pipe pile, and the steel pipe pile employing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide blades for a steel pipe pile, which have sufficient contact strength with respect to the steel pipe, and to provide the steel pipe pile employing the blades. <P>SOLUTION: The blades 21, 31 each have an intimate contact structure which allows an inner peripheral edge thereof to make intimate contact with an outer peripheral surface of the steel pipe. Specifically the inner peripheral edge of the blade 21 has slant surfaces 26a, 26b, and the inner peripheral edge of the blade 31 has slant surfaces 36a, 36b. Then an inclined angle of each of the slant surfaces 26a, 26b, 36a, 36b is set to a predetermined value so that each of the slant surfaces 26a, 26b, 36a, 36b makes intimate contact with the outer peripheral surface of the steel pipe when the blades 21, 31 are mounted on the same. Therefore even if the thickness of the blades 21, 31 is made larger, the inner peripheral edges of the respective blades 21, 31 make intimate contact with the outer peripheral surface of the steel pipe, to thereby ensure the sufficient contact strength of the blades with respect to the steel pipe. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a screw-type blade for a steel pipe pile used as a foundation of a building and a steel pipe pile using the same.
[0002]
[Prior art]
Conventionally, the following steel pipe piles are known. That is, as shown in FIG. 9A, the steel pipe pile 51 includes a steel pipe 52 and a pair of blades 53a and 53b fixed to the outer peripheral surface near the tip of the steel pipe 52 so as to be inclined at a predetermined angle. I have. When a rotational force and a pressing force in the screwing direction are applied to the steel pipe pile 51 by a construction device (not shown) installed on the ground, the steel pipe pile 51 is screwed into the ground by the screw action of the blades 53a and 53b (for example, And Patent Document 1.).
[0003]
[Patent Document 1]
JP-A-10-292370
[0004]
[Problems to be solved by the invention]
However, the conventional steel pipe pile has the following problems. That is, as shown in FIG. 9 (b), the blades 53a and 53b receive a reaction force (ground reaction force) from the ground as the steel pipe pile 51 is screwed into the ground, and the blades 53a and 53b Bending moment is applied. As a result, the blades 53a and 53b warp upward, and the ground supporting force of the steel pipe pile 51 is reduced.
[0005]
To solve this problem, it is conceivable to increase the thickness t of the blades 53a and 53b. By doing so, the rigidity of the blades 53a, 53b is increased, and the blades 53a, 53b are less likely to be deformed. However, as shown in FIG. Is increased. For this reason, rattling occurs between the inner peripheral edges of the blades 53a and 53b and the outer peripheral surface of the steel pipe 52, and the gap between the inner peripheral edges of the blades 53a and 53b and the outer peripheral surface of the steel pipe 52 is temporarily forcibly welded. Even if the blades 53a and 53b are fixed to the steel pipe 52, there is a possibility that the joining strength of the blades 53a and 53b to the steel pipe 52 cannot be secured.
[0006]
SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a steel pipe pile blade capable of securing joint strength to a steel pipe and a steel pipe pile using the same.
[0007]
[Means for Solving the Problems]
According to the first aspect of the present invention, the lower outer peripheral surface of the steel pipe is inclined downward at a predetermined mounting angle with respect to a plane perpendicular to the central axis of the steel pipe and in the rotation direction of the steel pipe when screwed into the ground. The gist of the present invention is to provide a blade for a steel pipe pile which is mounted so as to be provided with a close-contact structure on an inner peripheral edge of the blade for a steel pipe pile so as to closely contact the inner peripheral edge with an outer peripheral surface of the steel pipe.
[0008]
According to a second aspect of the present invention, in the first aspect of the present invention, the close structure includes an inclined surface formed on the inner peripheral edge of the steel pipe pile so that an inner peripheral edge of the blade is closely contacted with an outer peripheral surface of the steel pipe. The gist is that there is.
[0009]
According to a third aspect of the present invention, in the second aspect of the present invention, when the mounting angle of the steel pipe pile blade to the outer peripheral surface of the steel pipe is θ (θ <90 degrees), the surface of the steel pipe pile blade and The gist is that the inclined surface is formed so as to form a predetermined inclination angle (90 degrees-θ) with respect to an imaginary plane parallel to the back surface.
[0010]
According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, at least the starting end edge of the steel pipe pile blade is provided at the starting end edge and the steel pipe pile blade. The gist is that an inclined plane having a predetermined inclination angle with respect to a virtual plane parallel to the front surface and the back surface is formed.
[0011]
The invention according to claim 5 is a steel pipe pile according to any one of claims 1 to 4, wherein the steel pipe pile is screwed into the ground using a plurality of blades attached to a lower part of the steel pipe. The gist is that the wings are used.
[0012]
(Action)
According to the first aspect of the invention, when the steel pipe pile blade is attached to the outer peripheral surface of the steel pipe at a predetermined mounting angle, the inner peripheral edge of the steel pipe pile blade comes into close contact with the outer peripheral surface of the steel pipe. For this reason, rattling between the inner peripheral edge of the steel pipe pile blade and the outer peripheral surface of the steel pipe is suppressed.
[0013]
According to a second aspect of the present invention, in addition to the operation of the first aspect, the blade for a steel pipe pile comes into close contact with the outer peripheral surface of the steel pipe via an inclined surface formed on an inner peripheral edge thereof.
According to the invention described in claim 3, in addition to the effect of the invention described in claim 2, the inclined surface formed on the inner peripheral edge of the steel pipe pile blade is parallel to the front and back surfaces of the steel pipe pile blade. Make a predetermined inclination angle (90 degrees-θ) with respect to the virtual plane. For this reason, when the blade for steel pipe piles is mounted at an angle of θ with respect to the outer peripheral surface of the steel pipe pile, the inclined surface formed on the inner peripheral edge of the blade for steel pipe piles comes into close contact with the outer peripheral surface of the steel pipe pile.
[0014]
The invention according to claim 4 provides, in addition to the function of the invention according to any one of claims 1 to 3, at least the starting edge of the starting edge and the terminating edge of the steel pipe pile blade. An inclined surface that forms a predetermined inclination angle with respect to an imaginary plane that is parallel to the front surface and the back surface of the steel pipe pile blade is formed. For this reason, the resistance of the ground applied to the steel pipe pile blade is reduced.
[0015]
According to the invention as set forth in claim 5, the blade for steel pipe pile according to any one of claims 1 to 4 is used for the steel pipe pile.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment in which the present invention is embodied in a screw-in type steel pipe pile used as a foundation of a building, for example, will be described with reference to FIGS.
[0017]
(Overall configuration)
As shown in FIGS. 1, 2 and 7, the steel pipe pile 11 is a tubular steel pipe 12 having both ends opened, a plate-shaped closing member 13 for closing the lower end opening of the steel pipe 12, and a lower surface of the closing member 13. That is, it has a tip bit 14 provided on the tip face of the steel pipe 12 and a pair of blades 21 and 31 also provided on the lower peripheral face of the steel pipe 12.
[0018]
(Occlusion member)
The closing member 13 is fixed to the lower end opening of the steel pipe 12 by welding. When the steel pipe pile 11 is screwed into the ground, the closing member 13 pushes out the earth and sand or gravel on the lower end side of the steel pipe pile 11 to the outer peripheral side of the steel pipe pile 11, and after the screwing is completed, a reaction force from the ground (hereinafter, referred to as “the ground”). In response to "ground reaction force."
[0019]
(Tip bit)
The tip bit 14 (digging blade) is formed in a pentagonal shape by a plate material. The height of the tip bit 14 from the lower surface of the closing member 13 becomes higher toward the center of the lower surface of the closing member 13, and the height of the protrusion from the lower surface of the closing member 13 becomes lower toward the outer peripheral edge. It is fixed to be orthogonal to the lower surface of the closing member 13. When the steel pipe pile 11 is screwed into the ground, the tip bit 14 functions as an excavation guide that excavates and softens soil and gravel on the lower end side (tip side) of the steel pipe pile 11 and guides the screwing of the steel pipe pile 11 into the ground. .
[0020]
(Feather)
Next, the blades 21 and 31 will be described in detail with reference to FIG. FIG. 4 shows the blades 21 and 31 in a state cut out from one plate material by a laser beam L described later, and does not show a state where the blades 21 and 31 are attached to the steel pipe 12. In FIG. 4, the blade 21 has a lower surface on the near side of the drawing, and the blade 31 has an upper surface on the near side of the drawing. In the present embodiment, the upper surface and the lower surface refer to the upper surface and the lower surface when the blades 21 and 31 are attached to the outer peripheral surface of the steel pipe 12.
[0021]
As shown in FIG. 4, the blades 21 and 31 are formed by dividing a donut-shaped plate having an outer diameter larger than the outer diameter of the steel pipe 12 and having an inner diameter substantially equal to the outer diameter of the steel pipe 12 into two parts. It is formed in a fan shape. The blades 21 and 31 are fixed to the outer peripheral surface of the distal end of the steel pipe 12 at the respective inner peripheral edges by welding. The blades 21 and 31 have the same mounting angle θ with respect to a plane S1 (see FIG. 1) orthogonal to the central axis of the steel pipe 12, and rotate the steel pipe 12 when screwing it into the ground (see FIGS. 1 and 2). It is attached to the outer peripheral surface of the steel pipe 12 so as to incline downward in the direction indicated by arrow A).
[0022]
The range in which the mounting angle θ of the blades 21 and 31 can be taken is more than 0 degree and 15 degrees or less, and is set to 15 degrees in the present embodiment. If the mounting angle θ exceeds 15 degrees, the ground support force of the blades 21 and 31 cannot be secured, and the steel pipe pile 11 may sink. When the mounting angle θ is set to 0 °, the screwing of the steel pipe pile 11 into the ground may not be performed smoothly.
[0023]
The start ends 22a and 32a of the blades 21 and 31 are also located on the lower end side (downward in FIG. 1) of the steel pipe 12 with respect to the end parts 22b and 32b. The starting ends 22a and 32a of the blades 21 and 31 refer to the ends of the blades 21 and 31 on the rotation direction A side of the steel pipe pile 51, and the terminating ends 22b and 32b similarly indicate the ends of the steel pipe pile 51 of the blades 21 and 31. The end opposite to the rotation direction A is referred to.
[0024]
(Outer edge)
(Outer peripheral edge of the blade 21)
As shown in FIG. 3, FIG. 4 and FIG. 5 (c), on the outer peripheral edge of the blade 21, an inclined surface 23a is formed in the half on the side of the starting end 22a by cutting the upper surface thereof at an acute angle, and similarly the terminal end. An inclined surface 23b is formed in a half of the portion 22b by cutting the lower surface thereof at an acute angle. The inclined surface 23a and the inclined surface 23b are continuous with each other at the center of the outer peripheral edge of the blade 21.
[0025]
That is, as shown in FIG. 4, when the blade 21 is viewed from the lower surface side or the upper surface side, the width of the inclined surface 23 a is the maximum at the starting end edge 24 a of the blade 21 and goes toward the center of the outer peripheral edge of the blade 21. As the width of the inclined surface 23a gradually decreases, the width of the inclined surface 23a becomes 0 (zero) at the center of the outer peripheral edge. The width of the inclined surface 23b gradually increases from the center of the outer peripheral edge toward the terminal end portion 22b of the blade 21 and becomes maximum at the terminal end edge 24b of the blade 21.
[0026]
(Outer peripheral edge of the blade 31)
As shown in FIG. 3, FIG. 4 and FIG. 5 (d), on the outer peripheral edge of the blade 31, the inclined surface 33a is formed in the half on the side of the starting end 32a by cutting the upper surface thereof at an acute angle, and similarly the terminal end. An inclined surface 33b is formed in a half of the portion 32b by cutting the lower surface thereof at an acute angle. The inclined surface 33a and the inclined surface 33b are mutually continuous at the center of the outer peripheral edge of the blade 21.
[0027]
That is, as shown in FIG. 4, when the blade 31 is viewed from the lower surface side or the upper surface side, the width of the inclined surface 33 a is the maximum at the starting edge 24 a of the blade 31 and goes toward the center of the outer peripheral edge of the blade 31. As the width of the inclined surface 33a gradually decreases, the width of the inclined surface 33a becomes 0 (zero) at the center of the outer peripheral edge. Then, the width of the inclined surface 33b gradually increases from the center of the outer peripheral edge toward the terminal end portion 32b of the blade 31, and becomes maximum at the terminal edge 34b of the blade 31.
[0028]
As shown in FIGS. 3 and 5C, the inclined surfaces 23a and 23b form a predetermined inclination angle θ2 at the outer peripheral edge of the blade 21 with respect to a virtual plane S2 parallel to the front surface and the back surface of the blade 21. It is formed as follows. Also, as shown in FIGS. 3 and 5D, the inclined surfaces 33a and 33b each have a predetermined inclination angle θ2 at the outer peripheral edge of the blade 31 with respect to a virtual plane S2 parallel to the front surface and the back surface of the blade 31. Is formed. The inclination angle θ2 is set in accordance with the mounting angle θ of the blades 21 and 31, and the inclination angle θ2 is (90−θ) degrees. In the present embodiment, since the attachment angle θ is set to 15 degrees, θ2 is set to 75 degrees.
[0029]
Therefore, when the blades 21 and 31 are mounted on the outer peripheral surface of the steel pipe 12 at a predetermined mounting angle θ, the outer peripheral edges of the blades 21 and 31, that is, the plane including the inclined surfaces 23 a and 33 b and the plane including the inclined surfaces 33 a and 23 b. Are perpendicular to a plane S1 perpendicular to the central axis of the steel pipe 12, respectively.
[0030]
(Starting edge / ending edge)
As shown in FIG. 4 and FIG. 5A, an inclined surface 25a is formed at the starting end 24a of the blade 21 by cutting the upper surface thereof at an acute angle. As shown in FIG. 4 and FIG. 5B, an inclined surface 25b is formed at the terminal edge 24b of the blade 21 by cutting the upper surface thereof at an acute angle. Further, as shown in FIGS. 4 and 5A, an inclined surface 35b is formed at the terminal edge 34b of the blade 31 by cutting the upper surface thereof at an acute angle. As shown in FIG. 4 and FIG. 5B, an inclined surface 35a is formed at the starting edge 34a of the blade 31 by cutting the upper surface thereof at an acute angle.
[0031]
The inclined surfaces 25a and 25b are formed so as to form a predetermined inclination angle θ3 with respect to a virtual plane S2 parallel to the front surface and the back surface of the blade 21, respectively. The inclined surfaces 35a and 35b are formed so as to form a predetermined inclined angle θ3 with respect to a virtual plane S2 parallel to the front surface and the back surface of the blade 31, respectively. The range that the inclination angle θ3 can take is 20 degrees or more and less than 90 degrees, a desirable range is 30 to 60 degrees, and an optimal range is 35 to 90 degrees, and is 45 degrees in the present embodiment. Exceeding this range makes it difficult to machine the inclined surfaces 25a, 25b, 35a, 35b. This is because it exceeds the tiltable range of the table 42 of the laser processing device 41 described later. Below this range, the blades 21 and 31 will have insufficient strength.
[0032]
(Inner periphery)
(Inner periphery of the blade 21)
As shown in FIG. 4 and FIG. 5 (c), an inclined surface 26a is formed by cutting the lower surface side of the half of the inner peripheral edge of the blade 21 on the side of the start end 22a at an acute angle, and similarly, on the side of the end 22b. An inclined surface 26b is formed in the half by cutting the upper surface thereof at an acute angle. The inclined surfaces 26a and 26b are continuous with each other with the center of the inner peripheral edge of the blade 21 as a boundary.
[0033]
That is, as shown in FIG. 4, when the blade 21 is viewed from the lower surface side or the upper surface side, the width of the inclined surface 26 a is the largest at the starting edge 24 a of the blade 21 and goes toward the center of the inner peripheral edge of the blade 21. As the width of the inclined surface 26a gradually decreases, the width of the inclined surface 26a becomes 0 (zero) at the center of the outer peripheral edge. The width of the inclined surface 26b gradually increases from the center of the inner peripheral edge toward the terminal end portion 22b of the blade 21 and becomes maximum at the terminal edge 24b of the blade 21.
[0034]
(Inner edge of blade 31)
As shown in FIGS. 4 and 5 (c), an inclined surface 36a is formed by cutting the lower surface side of the half of the inner peripheral edge of the blade 31 at the start end portion 32a at an acute angle, and similarly at the end portion 32b side. An inclined surface 36b is formed in the half by cutting the upper surface thereof at an acute angle. The inclined surface 36a and the inclined surface 36b are continuous with each other at the center of the inner peripheral edge of the blade 31.
[0035]
That is, as shown in FIG. 4, when the blade 31 is viewed from the lower surface side or the upper surface side, the width of the inclined surface 36 a is maximum at the terminal edge 34 b of the blade 31 and goes toward the center of the inner peripheral edge of the blade 31. As a result, the width of the inclined surface 36a gradually decreases, and the width of the inclined surface 36a becomes 0 (zero) at the center of the outer peripheral edge. Then, the width of the inclined surface 36b gradually increases from the center of the inner peripheral edge toward the start end portion 22a of the blade 31 and becomes maximum at the start end edge 24a of the blade 31.
[0036]
The inclined surfaces 26a and 26b are formed so as to form a predetermined inclination angle θ4 with respect to a virtual plane S2 parallel to the front surface and the back surface of the blade 21, respectively. The inclined surfaces 36a and 36b are formed so as to form a predetermined inclination angle θ4 with respect to a virtual plane S2 parallel to the front surface and the back surface of the blade 31, respectively. The inclination angle θ4 is set according to the mounting angle θ of the blades 21 and 31, and the inclination angle θ4 is (90−θ) degrees. In the present embodiment, since the mounting angle θ is set to 15 degrees, θ4 is set to 75 degrees.
[0037]
Therefore, when the blades 21 and 31 are mounted on the outer peripheral surface of the steel pipe 12 at a predetermined mounting angle θ, the inner peripheral edges of the blades 21 and 31, that is, the inclined surfaces 26 a and 26 b and the inclined surfaces 36 a and 36 b, Close to the surface.
[0038]
Now, when screwing the steel pipe pile 11 into the ground, the blades 21 and 31 bite into the unexcavated ground (soil and sand and gravel) on the outer peripheral side of the steel pipe pile 11 due to the rotation of the steel pipe pile 11. The strength of earth and sand and gravel acts as a reaction force. Therefore, a driving force in the screwing direction acts on the steel pipe pile 11. After the screwing of the steel pipe pile 11 is completed, the steel pipe pile 11 receives the ground reaction force together with the closing member 13 to exhibit the ground supporting force.
[0039]
(Production method of feather)
Next, a method of manufacturing the blades 21 and 31 will be described. In the present embodiment, the flat plate-shaped workpiece is cut out into a predetermined shape (for example, a donut shape) by a laser beam irradiated from a nozzle of a laser processing apparatus, and the plate member having the predetermined shape is cut in half at the center thereof, thereby making the blade 21 , 31 are formed.
[0040]
That is, as shown in FIG. 6, first, a flat work W is placed on a table 42 of a laser processing apparatus 41, and the work W is immovably fixed to the table 42 by a work fixing jig (not shown). .
[0041]
Here, the table 42 is swingable in the left-right direction in FIG. 6 around the shaft 43 by the operation of a table driving mechanism (not shown). Further, the laser processing device 41 includes a movable processing head 44, and the processing head 44 is provided with a nozzle 45 for irradiating the laser beam L. The nozzle 45 is provided on the processing head 44 such that the laser beam L emitted from the nozzle 45 is orthogonal to the horizontal plane Sh.
[0042]
Next, the table drive mechanism is operated to tilt the table 42 by a predetermined table tilt angle θt with respect to the horizontal plane Sh. At this time, the table inclination angle θt is set according to the desired inclination angle of the cut edge (for example, the inclination angles θ2, θ3, θ4). In this state, while irradiating the workpiece W with the laser beam L from the nozzle 45 of the laser processing device 41, the nozzle 45 is moved in accordance with the processing shape (for example, a circular motion or a linear motion is performed). As a result, the inclination angle of the cut edge of the work W is (90-θt) degrees with respect to the virtual plane S2.
[0043]
More specifically, when forming the outer peripheral edges of the blades 21 and 31, the table inclination angle θt is set to 15 degrees. In this state, the nozzle 45 is moved so as to draw a circle while irradiating the work W with the laser beam L so as to be orthogonal to the horizontal plane Sh. Then, as shown in FIG. 4, a circular plate member is cut out from the work W, and its outer peripheral edge (corresponding to the outer peripheral edges of the blades 21 and 31) forms an angle of 75 degrees with the virtual plane S2. An inclined surface is formed. That is, the inclined surfaces 23a and 23b and the inclined surfaces 33a and 33b having the inclination angle θ2 = 75 degrees are formed collectively (first step).
[0044]
Next, when forming the inner peripheral edges of the blades 21 and 31, the table 42 is inclined to the side opposite to the case where the outer peripheral edge is formed, and the table inclination angle θt is set to 15 degrees. In this state, the nozzle 45 is moved so as to draw a circle while irradiating the work W with the laser beam L so as to be orthogonal to the horizontal plane Sh. Then, as shown in FIG. 4, a donut-shaped plate member is cut out, and its inner peripheral edge (corresponding to the inner peripheral edge of the blades 21 and 31) has an inclined surface forming 75 degrees with respect to the virtual plane S <b> 2. Is formed. That is, the inclined surfaces 26a and 26b and the inclined surfaces 36a and 36b having the inclination angle θ4 = 75 degrees are formed collectively (second step).
[0045]
Finally, when forming the start edge and the end edge of the blades 21 and 31, the table inclination angle θt is set to 45 degrees. In this state, the donut-shaped plate member is cut in half at its center so as to be orthogonal to the horizontal plane Sh. Then, as shown in FIG. 4, an inclined surface that forms 45 degrees with respect to the virtual plane S2 is formed on the cut edges (corresponding to the start edges 24a and 34a and the end edges 24b and 34b). That is, the inclined surfaces 25a and 25b and the inclined surfaces 35a and 35b having the inclination angle θ3 = 45 degrees are formed collectively (third step).
[0046]
Thus, the manufacture of the blades 21 and 31 is completed. As described above, since the respective inclined surfaces are formed together with the formation of the blades 21 and 31, the respective inclined surfaces are formed when the respective inclined surfaces are separately formed or after the blades 21 and 31 are fixed to the steel pipe 12. The manufacture of the blades 21 and 31 is simpler than in the case where the above-described case is adopted. Further, the number of manufacturing steps for the blades 21 and 31 can be reduced.
[0047]
(Operation of the embodiment)
Next, an operation at the time of construction of the steel pipe pile configured as described above will be described.
When the steel pipe pile 11 is buried in the ground, the steel pipe pile 11 is erected on the ground where the steel pipe pile 11 is to be buried by a construction device (not shown) installed on the ground, and in this state, the steel pipe pile 11 is turned in the rotational direction and the screwing direction. Of pressing force. Then, the steel pipe pile 11 is screwed into the ground (underground) by the screw action of the blades 21 and 31 while excavating and softening the ground with the tip bit 14. That is, the blades 21 and 31 bite into the ground on the outer peripheral side of the steel pipe pile 11, and rotate and propel the steel pipe pile 11 into the ground as a reaction force with the strength of the earth and sand or gravel acting on the upper surfaces of the blades 21 and 31. The earth and sand and gravel on the lower end side of the steel pipe pile 11 are pushed out to the outer peripheral side of the steel pipe pile 11 as the steel pipe pile 11 is screwed. When the lower end (tip) of the steel pipe pile 11 reaches a predetermined support layer (not shown), the screwing of the steel pipe pile 11 into the ground is completed.
[0048]
(Effects of the embodiment)
Therefore, according to the present embodiment, the following effects can be obtained.
(1) The inner peripheral edges of the blades 21 and 31 are provided with a close contact structure for bringing the inner peripheral edge into close contact with the outer peripheral surface of the steel pipe 12. Specifically, the inclined surfaces 26a and 26b are continuously formed on the inner peripheral edge of the blade 21, and the inclined surfaces 36a and 36b are continuously formed on the inner peripheral edge of the blade 31. When the blades 21 and 31 are attached to the outer peripheral surface of the steel pipe 12, the inclined surfaces 26a and 26b and the inclined surfaces 36a and 36b are so closely contacted with the inclined surfaces 26a and 26b and the inclined surfaces 36a and 36b, respectively. The inclination angle θ4 is set.
[0049]
For this reason, even if the thickness t of the blades 21, 31 is increased in order to suppress the deformation of the blades 21, 31 due to the screwing of the steel pipe pile 11 into the ground, the inner peripheral edges of the blades 21, 31 are formed by the steel pipe 12. And the rattle does not occur between the inner peripheral edges of the blades 21 and 31 and the outer peripheral surface of the steel pipe 12. Therefore, the joining strength (welding strength) of the blades 21 and 31 to the outer peripheral surface of the steel pipe 12 can be ensured. In addition, the rigidity of the blades 21 and 31 is increased as the thickness t increases, and the upward curling of the blades 21 and 31 due to the screwing of the steel pipe pile 11 into the ground is suppressed. As a result, the ground support force of the blades 21 and 31 can be secured, and the outer diameter d (see FIG. 2) of the blades 21 and 31 can be reduced.
[0050]
(2) Assuming that the angle of attachment of the blades 21 and 31 to the outer peripheral surface of the steel pipe 12 is θ (θ <90 degrees), the inclined surfaces 26a and 26b and the inclined surfaces 36a and 36b are formed on the front and back surfaces of the blades 21 and 31. It was formed so as to form a predetermined inclination angle (90 degrees-θ) with respect to the parallel virtual plane S2. Therefore, the inner peripheral edges of the blades 21 and 31 can be brought into close contact with the outer peripheral edge of the steel pipe 12 in accordance with the mounting angle θ of the blades 21 and 31 with respect to the outer peripheral surface of the steel pipe 12.
[0051]
(3) On the start edge 24a and the end edge 24b of the blade 21, an inclined surface 25a and an inclined surface 25b are respectively formed at a predetermined inclination angle θ3 with respect to a virtual plane S2 parallel to the front surface and the back surface of the blade 21. I did it. In addition, inclined surfaces 35a and 35b that form a predetermined inclination angle θ3 with respect to a virtual plane S2 that is parallel to the front surface and the back surface of the blade 21 are formed on the start edge 34a and the end edge 34b of the blade 31, respectively. I made it. For this reason, when the steel pipe pile 11 is screwed into the ground, the resistance of the ground applied to the start edge 24a and the end edge 24b of the blade 21 and the start edge 34a and the end edge 34b of the blade 31 is reduced. Therefore, the torque required when screwing the steel pipe pile 11 into the ground is reduced, and the steel pipe pile 11 can be easily screwed into the ground.
[0052]
(4) On the outer peripheral edge of the blade 21, inclined surfaces 23a and 23b forming a predetermined inclined angle θ2 with respect to a virtual plane S2 parallel to the front surface and the back surface of the blade 21 are formed continuously. Further, on the outer peripheral edge of the blade 31, inclined surfaces 33a, 33b are formed continuously at a predetermined inclination angle θ2 with respect to a virtual plane S2 parallel to the front surface and the back surface of the blade 31. For this reason, the resistance from the ground on the outer peripheral side of the steel pipe pile 11 is reduced, and the blades 21 and 31 can easily bite into the ground. Therefore, when the steel pipe pile 11 is screwed into the ground, the rotation of the steel pipe pile 11 can be made smoother.
[0053]
(5) The doughnut-shaped plate member is cut out from the plate-shaped work W by the laser beam L, and the plate member is cut in half at the center thereof to form the blades 21 and 31. At this time, the work W is irradiated with the laser beam L so as to be orthogonal to the horizontal plane Sh while the work W is inclined with respect to the horizontal plane Sh by a predetermined table inclination angle θt. The table tilt angle θt is changed in accordance with the processing part on the blades 21 and 31.
[0054]
Therefore, simultaneously with the formation of the blades 21 and 31, the respective inclined surfaces 23a, 23b, 33a, 33b, 25a, 25b, 35a, 35b, 26a, 26b, 36a, and 36b are respectively formed. Therefore, the manufacture of the blades 21 and 31 is simplified. Further, the number of manufacturing steps of the blades 21 and 31 can be reduced, and the manufacturing efficiency of the blades 21 and 31 can be improved. As a result, the man-hour for manufacturing the steel pipe pile 11 can be reduced, and the manufacturing efficiency of the steel pipe pile 11 can be improved.
[0055]
(Another example)
The above-described embodiment may be modified and implemented as follows.
In the present embodiment, the slopes 25a and 25b are formed at the start edge 24a and the end edge 24b of the blade 21, respectively, and the slopes 35a and 35b are respectively formed at the start edge 34a and the end edge 34b of the blade 31. Is formed, but may be formed as follows. That is, the inclined surfaces 25a and 35a may be formed only on the starting edges 24a and 34a of the blades 21 and 31. In other words, the inclined surfaces 25b, 35b of the terminal edges 24b, 34b are not formed.
[0056]
In the present embodiment, the slopes 25a and 25b are formed at the start edge 24a and the end edge 24b of the blade 21, respectively, and the slopes 35a and 35b are respectively formed at the start edge 34a and the end edge 34b of the blade 31. Is formed, but may be formed as follows. That is, the inclined surfaces 25a, 25b, 35a, 35b are not formed.
[0057]
In the present embodiment, the inclined surfaces 23a and 23b are formed on the outer peripheral edge of the blade 21 and the inclined surfaces 33a and 33b are formed on the outer peripheral edge of the blade 31. However, each of the inclined surfaces 23a, 23b and 33a is formed. , 33b may not be formed. In this case, for example, the outer peripheral edges of the blades 21 and 31 are formed so as to be orthogonal to the virtual plane S2.
[0058]
In the present embodiment, the outer peripheral edges of the blades 21 and 31 are formed, and then the inner peripheral edges of the blades 21 and 31 are formed. However, they may be formed in the reverse order. That is, after the inner peripheral edges of the blades 21 and 31 are formed, the outer peripheral edges of the blades 21 and 31 are formed.
[0059]
In the present embodiment, at the time of manufacturing the blades 21 and 31, the work W is inclined with respect to the horizontal plane Sh by a predetermined table inclination angle θt, and in this state, the laser beam L is irradiated so as to be orthogonal to the horizontal plane Sh. Then, the work W is processed, but the following may be performed. That is, as shown in FIG. 8, the workpiece W may be processed in a state where the nozzle 45 is inclined by a predetermined angle with respect to the horizontal plane Sh.
[0060]
(Note)
Next, technical ideas that can be grasped from the embodiment and other examples will be additionally described below.
(A) The steel pipe is mounted so as to be inclined downward at a predetermined mounting angle with respect to a plane perpendicular to the central axis of the steel pipe with respect to a lower outer peripheral surface of the steel pipe in a rotation direction of the steel pipe when screwed into the ground. In the method of manufacturing a blade for a steel pipe pile, a plate-shaped work is inclined by a predetermined angle with respect to a horizontal plane, and in this state, the work is processed by irradiating a laser beam orthogonally to the horizontal plane. A method for manufacturing blades for steel pipe piles. According to this configuration, the inclined surface is formed together with the formation of the blade for the steel pipe pile.
[0061]
(B) A plate member having a predetermined shape is cut out from the work by the laser beam, and the plate member is cut in half at the center thereof to form a blade for a steel pipe pile. The predetermined shape is a donut shape. The manufacturing of the steel pipe pile blade according to the above item (a), wherein the work is inclined by a predetermined inclination angle (θt) with respect to the horizontal plane when forming at least the inner peripheral edge of the peripheral edge and the inner peripheral edge. Method. According to this configuration, an inclined surface is formed at least on the inner peripheral edge together with the formation of the steel pipe pile blade.
[0062]
(C) A method of manufacturing a blade for steel pipe piles, wherein the work is inclined at a predetermined inclination angle (θt) with respect to a horizontal plane even when the donut-shaped plate member is cut in half at its center. According to this configuration, together with the formation of the plurality of blades for steel pipe piles, the inclined surfaces are respectively formed at the start edge and the end edge of each blade for steel pipe piles.
[0063]
(D) any one of the above (a) to (c), wherein the work is inclined by a predetermined inclination angle (θt) with respect to the horizontal plane even when cutting a plate member of a predetermined shape from the work. The method for producing a blade for a steel pipe pile according to any one of the preceding claims. According to this configuration, the inclined surface is formed on the outer peripheral edge of the steel pipe pile blade together with the formation of the steel pipe pile blade.
[0064]
(E) The blade for a steel pipe pile according to claim 4, wherein the inclination angle of the inclined surface at the starting end is set in a range of 20 degrees or more and less than 90 degrees.
(F) An inclined surface having a predetermined inclination angle with respect to an imaginary plane parallel to the front surface and the back surface of the steel pipe pile blade is continuously formed on the outer peripheral edge of the steel pipe pile blade. The blade for a steel pipe pile according to claim 4. According to this configuration, the resistance of the ground on the outer peripheral side of the steel pipe pile is reduced, and the blades for the steel pipe pile can easily bite into the ground.
[0065]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the joining intensity | strength with respect to a steel pipe of the said blade for steel pipe piles can be ensured by the inner peripheral edge of the blade for steel pipe piles being close to the outer peripheral surface of a steel pipe.
[Brief description of the drawings]
FIG. 1 is a front view of a steel pipe pile according to an embodiment.
FIG. 2 is a bottom view of the steel pipe pile according to the embodiment.
FIG. 3 is a front sectional view of a main part of the steel pipe pile according to the embodiment.
FIG. 4 is a front view at the time of processing the blade for the steel pipe pile according to the embodiment.
FIG. 5A is a sectional view taken along line 1-1 in FIG. 4;
(B) is a sectional view taken along line 2-2 in FIG.
(C) is a sectional view taken along line 3-3 in FIG.
(D) is a sectional view taken along line 4-4 in FIG.
FIG. 6 is a schematic configuration diagram of a laser processing apparatus showing a processing state of a blade for a steel pipe pile according to the present embodiment.
FIG. 7 is a side view of the steel pipe pile according to the embodiment.
FIG. 8 is a schematic configuration diagram of another laser processing apparatus showing a processing state of a steel pipe pile blade in the present embodiment.
FIG. 9A is a front view of a main part of a conventional steel pipe pile,
(B) is a principal part front view which shows the curvature of the conventional blade for steel pipe piles.
FIG. 10 is an enlarged front sectional view of a main part of a conventional steel pipe pile.
[Explanation of symbols]
11 ... steel pipe pile, 12 ... steel pipe, 21, 31 ... blade (blade for steel pipe pile),
23a, 23b: inclined surfaces formed on the outer peripheral edge of the steel pipe pile blade,
24a, 34a: Starting edge of blade for steel pipe pile,
24b, 34b: terminal edge of blade for steel pipe pile,
25a, 35a: inclined surface formed at the starting edge of the blade;
25b, 35b ... inclined surface formed at the terminal edge of the blade,
26a, 26b: inclined surfaces forming a close structure,
33a, 33b: inclined surfaces formed on the outer peripheral edge of the steel pipe pile blade,
36a, 36b: inclined surfaces forming a close structure;
A: rotating direction of steel pipe, L: laser beam, S1: plane perpendicular to the central axis of steel pipe,
S2: an imaginary plane parallel to the front and back surfaces of the blade,
Sh: horizontal plane, W: workpiece, θ: mounting angle of blade for steel pipe pile,
θ2: the inclination angle of the inclined surface formed on the outer peripheral edge of the steel pipe pile blade,
θ3: the inclination angle of the inclined surface formed at the starting edge of the blade,
θ4: the inclination angle of the inclined surface formed on the inner peripheral edge of the blade,
θt: Table tilt angle.

Claims (5)

A steel pipe pile mounted on a lower outer peripheral surface of a steel pipe so as to form a predetermined mounting angle with respect to a plane orthogonal to a central axis of the steel pipe and to incline downward in a rotation direction of the steel pipe when screwed into the ground. In the wings,
A blade for a steel pipe pile, wherein an inner peripheral edge of the blade for a steel pipe pile is provided with a close structure for closely contacting the inner peripheral edge with an outer peripheral surface of the steel pipe. The blade for a steel pipe pile according to claim 1, wherein the close contact structure is an inclined surface formed on the inner peripheral edge of the steel pipe pile so that the inner peripheral edge of the blade closely contacts the outer peripheral surface of the steel pipe. When the attachment angle of the steel pipe pile blade to the outer peripheral surface of the steel pipe is θ (θ <90 °), a predetermined inclination angle (90 ° − The blade for a steel pipe pile according to claim 2, wherein the inclined surface is formed so as to satisfy θ). At least the starting edge of the starting edge and the terminating edge of the steel pipe pile blade has a slope formed at a predetermined angle with respect to an imaginary plane parallel to the front and back surfaces of the steel pipe pile blade. The blade for steel pipe piles according to any one of claims 1 to 3. In a steel pipe pile that was screwed into the ground using multiple blades attached to the bottom of the steel pipe,
A steel pipe pile using the steel pipe pile blade according to any one of claims 1 to 4.

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