JP7743326B2 - Expanding Drilling Rig - Google Patents

Description

The present invention relates to an expansion drilling device used in construction work to expand and excavate the tip of a pile hole formed in the ground to form a root-hardening bulb.

A variety of structures and functions have been proposed for enlarging and excavating the tip of a pile hole formed in the ground to form a root-hardening bulb. One example of a device related to the present invention is the "enlargement excavation device" described in Patent Document 1.

The "expansion drilling device" described in Patent Document 1 is used by connecting it to the tip of a drilling rod so that it rotates integrally with the drilling rod. This expansion drilling device is equipped with a hollow drive shaft connected to the drilling rod, two spiral drilling blades attached to the outer periphery of the drive shaft, drilling blades attached to the tip of each drilling blade, and two expansion blades attached along the spiral of each drilling blade and configured to be switchable between an expanded and a contracted diameter state.

The two expansion wings are supported by pins on brackets connected to the drilling wings so that they can swing freely. When the drilling rod is rotated forward to excavate a pile hole, soil pressure causes the majority of the wings to be contained within the rotational path of the drilling wings, resulting in a reduced diameter state. When the drilling rod is rotated backward, the expansion wings are subjected to soil pressure and swing around the pins, expanding their diameter and protruding radially outward from the rotational path of the drilling wings.

JP 2011-214366 A

The "expansion drilling device" described in Patent Document 1 performs expansion drilling using two expansion blades that are arranged along the spiral of two spiral drilling blades and are configured to be switchable between an expansion state and a contraction state. However, because the size of the expansion blades (the radial size of the rotation surface of the drilling rod) is smaller than the drilling blades, there is a problem in that the expansion drilling rate is low.

Furthermore, in the case of the above-mentioned "expansion excavation device," if the size of the expansion wings is increased in order to increase the expansion excavation rate, the load applied to the area near the bracket by earth pressure during expansion excavation work becomes excessive, increasing the possibility of damage, so the reality is that it is difficult to increase the expansion excavation rate by increasing the size of the expansion wings.

The problem that this invention aims to solve is to provide an expansion drilling device that has a simple structure composed only of mechanical elements, is strong, and has a higher expansion drilling rate than conventional expansion drilling devices.

The expansion drilling device according to the present invention is
a drilling shaft that can be connected to the tip of the drilling rod so as to rotate integrally with the drilling rod;
A plurality of support shafts are arranged on the outer periphery of the drilling shaft, parallel to the axis of the drilling shaft, and equally spaced along the circumferential direction of the drilling shaft;
an expansion wing rotatably attached to the support shaft,
During pile hole excavation work in which the drilling rod rotates forward, the expansion wings, which are subjected to earth pressure, maintain a contracted diameter state.
During enlarged excavation work in which the drilling rod rotates in the reverse direction, the expansion blades, subjected to earth pressure, rotate around the support shaft and maintain an expanded diameter state until a portion of the expansion blades abuts against the outer periphery of the drilling shaft.

In the expansion drilling device, multiple expansion wings can be arranged so that they overlap along the axial direction of the drilling shaft.

The expansion drilling device may be provided with an expansion confirmation member that is sheared when the expansion wing rotates to the expanded diameter state.

In the expansion drilling device, at least one conical bit can be provided on at least one of the upper and lower surfaces of the expansion wing.

The present invention makes it possible to provide an expansion drilling device that has a simple structure consisting only of mechanical elements, is highly strong, and has a higher expansion drilling rate than conventional expansion drilling devices.

1 is a partially omitted front view showing an expansion drilling device according to an embodiment of the present invention. FIG. 2 is a partially omitted horizontal cross-sectional view taken along line AA in FIG. 1, showing the expansion vane in a contracted state. FIG. 2 is a partially omitted horizontal cross-sectional view taken along line AA in FIG. 1, showing the expansion vane in a state where its diameter is expanded. 2 is a partially omitted front view showing a state in which a drilling head is connected to the expansion drilling device shown in FIG. 1. [0023] FIG. FIG. 2 is a partially omitted vertical cross-sectional view showing the expansion drilling device shown in FIG. 1 in use (with the expansion blades contracted in diameter). FIG. 10 is a partially omitted front view showing a state in which a drilling head is connected to an expansion drilling device according to another embodiment. FIG. 7 is a partially omitted vertical cross-sectional view showing the expansion drilling device shown in FIG. 6 in use (with the expansion blades contracted in diameter). FIG. 7 is a partially omitted perspective view showing the vicinity of a diameter expansion confirmation member of the expansion drilling device shown in FIG. 6 . FIG. 9 is a partially omitted perspective view showing the vicinity of a diameter expansion confirmation member in FIG. 8 . FIG. 10 is a partially omitted perspective view showing an expansion drilling device according to another embodiment.

The following describes an embodiment of the present invention, an expansion drilling device 100, with reference to Figures 1 to 5. As shown in Figure 5, the expansion drilling device 100 shown in Figures 1 to 3 comprises a drilling rod 1 equipped with a drive shaft 2 that is driven to rotate in forward and reverse directions by a drive means (not shown) and a spiral drilling blade 3 attached to the outer periphery of the drive shaft 2; a drilling shaft 10 that can be connected to the tip of the drive shaft 2 so as to rotate integrally with the drilling rod 1; a plurality of support shafts 13 that are parallel to the axis 10c of the drilling shaft 10 on the outer periphery of the drilling shaft 10 and are equally spaced around the periphery of the drilling shaft 10; and expansion blades 11 rotatably attached to each support shaft 13.

As shown in FIG. 1, each support shaft 13 is fixed at a position away from the outer periphery of the drilling shaft 10 via a pair of brackets 16, 16 spaced apart in a direction parallel to the axis 10c. As shown in FIGS. 2 and 3, the expansion wing 11 has a tapered shape in plan view that continuously narrows with increasing distance from the support shaft 13, and its tip 11d has a planar shape parallel to the vertical direction (the direction of the axis 10c), with the base end provided with a protrusion 11b that protrudes away from the tip 11d and a recess 11c adjacent to the protrusion 11b and recessed toward the tip 11d. The expansion wings 11 are arranged at three locations at 120-degree intervals around the outer periphery of the drilling shaft 10, but the shape, number, and spacing of the expansion wings 11 are not limited to the configuration shown in FIGS. 2 and 3.

A diameter expansion confirmation bolt 18 is located on the outer periphery of each of the brackets 16, closer to the drilling shaft 10 than the support shaft 13. The structure and function of the area around the diameter expansion confirmation bolt 18 will be described in detail later with reference to Figures 8 and 9.

As shown in Figure 1, a hexagonal prism-shaped connector 14a protrudes from the upper end of the drilling shaft 10 for connection to the lower end of the drive shaft 2 of the drilling rod 1, and a connector hole 14b is drilled in the direction of the axis 10c from the lower end of the drilling shaft 10, into which the connector 22 protruding from the upper end of the drive shaft 21 of the drilling head 20 shown in Figure 4 can be fitted.

When using the enlarged drilling device 100 shown in Figure 1, as shown in Figure 4, the drilling head 20 is connected to the lower end of the enlarged drilling device 100. The drilling head 20 comprises a cylindrical drive shaft 21, a hexagonal prism-shaped connector 22 protruding from the upper end of the drive shaft 21, and a spiral drilling blade 23 attached to the outer periphery of the drive shaft 21. The connector 22 on the upper end of the drilling head 20 is inserted into the connector hole 14b on the lower end of the drilling shaft 10 of the enlarged drilling device 100 and fixed using a predetermined fixing means, thereby connecting the enlarged drilling device 100 and the drilling head 20 together.

Next, as shown in Figure 4, the enlarged drilling device 100 integrated with the drilling head 20 is connected to the tip of the drive shaft 2 of the drilling rod 1 so that it rotates integrally with the drilling rod 1. Specifically, the connector 14a on the upper end of the drilling shaft 10 of the enlarged drilling device 100 is inserted into the connector hole 4 (see Figure 5) drilled at the tip of the drive shaft 2 and fixed with a predetermined fixing means, thereby integrally connecting the drilling rod 1 to the enlarged drilling device 100 and drilling head 20. As a result, the enlarged drilling device 100 and drilling head 20 are connected to rotate integrally with the drilling rod 1.

Here, the functions, effects, etc. of the expansion wing 11 that constitutes the expansion drilling device 100 will be explained based on Figures 2 to 5.

As shown in Figure 5, when drilling a pile hole, the drilling rod 1 is rotated forward in the direction of arrow R. At this time, as shown in Figure 2, the tip 11d of the expansion blade 11, which is subjected to earth pressure, remains close to the drilling shaft 10, so the expansion blade 11 is kept in a reduced diameter state. Therefore, by rotating the drilling rod 1 forward in the direction of arrow R, pile hole drilling can be carried out smoothly.

On the other hand, during enlargement excavation work, the drill rod 1 is rotated in the reverse direction of arrow L. At this time, as shown in Figure 3, the multiple expansion wings 11, under soil pressure, rotate around the support shaft 13, expanding until the protrusions 11b of the expansion wings 11 abut the outer periphery of the drilling shaft 10, and are maintained in an expanded, shuriken-shaped state as shown in Figure 3. Therefore, the multiple expansion wings 11 rotating in the direction of arrow L with a larger rotation radius than the drilling blades 23 (see Figure 5), enlarge and excavate the ground around the expansion wings 11 of the pile hole H formed in the ground as shown in Figure 5, forming a root compaction bulb (not shown) with an inner diameter larger than that of the pile hole H.

As mentioned above, the expansion wing 11 of the expansion drilling device 100 shown in Figure 3 rotates in the direction of arrow L with a large radius of rotation to expand and excavate the ground around the pile hole H (see Figure 5), thereby achieving a higher expansion excavation rate than conventional expansion drilling devices. Furthermore, when the expansion wing 11 rotates in the direction of arrow L to excavate the ground, the reaction force of the earth pressure generated on the protrusion 11b is supported by the outer periphery of the drilling shaft 10 (the portion where the protrusion 11b abuts), making it less susceptible to damage and providing high strength despite its simple structure.

Furthermore, as shown in Figure 3, the support shaft 13 is positioned away from the outer periphery of the drilling shaft 10, so that soil and sand accumulated between the support shaft 13 and the reaction point (protrusion 11b) does not get caught when the expansion blade 11 expands, ensuring smooth expansion operation.

After the expansion drilling operation is completed, the drilling rod 1 (see Figure 5) is rotated forward in the direction of arrow R, causing the multiple expansion wings 11, which have received earth pressure, to return to the reduced diameter state shown in Figures 1 and 2, allowing the expansion drilling device 100 and drilling head 20, together with the drilling rod 1, to be easily raised to the ground.

The expansion blades 11 that make up the expansion drilling device 100 expand or contract in diameter simply by rotating the drilling shaft 10 in the forward or reverse direction via the drilling rod 1, so no hydraulic or electrical operating systems are required. Therefore, the expansion drilling device 100 can be constructed solely from mechanical elements, and its structure is simple.

Next, another embodiment of the expansion drilling device 200 will be described with reference to Figures 6 to 9. Note that parts of the expansion drilling device 200 that are common to the expansion drilling device 100 described above will be assigned the same reference numerals as those shown in Figures 1 to 5, and descriptions thereof will be omitted.

Figure 6 shows the drilling head 20 integrally connected to the expansion drilling device 200. As shown in Figure 6, in the expansion drilling device 200, an upper expansion wing 11 and a lower expansion wing 12 are arranged in the position of the expansion wing 11 of the expansion drilling device 100 shown in Figure 1. The upper expansion wing 11 and the lower expansion wing 12 are arranged one above the other along the axial center 10c of the drilling shaft 10, and are attached to the outer periphery of the drilling shaft 10 via a support shaft 13 and a bracket 16.

The upper and lower expansion wings 11 and 12 can rotate around the support shaft 13 without interfering with each other. The shape and function of the upper and lower expansion wings 11 and 12 are similar to those of the expansion wings 11 shown in Figures 2 and 3, and the upper and lower expansion wings 11 and 12 have similar structures, functions, etc.

The expansion drilling device 200 is used in the same way as the expansion drilling device 100 shown in Figure 5. As shown in Figure 7, the expansion drilling device 200, together with the drilling head 20, is connected to the tip of the drilling rod 1 so that it rotates integrally with the drilling rod 1.

The upper and lower expansion wings 11 and 12 that make up the expansion drilling device 200 expand or contract in diameter in the same way as the expansion wings 11 shown in Figures 2 and 3, simply by rotating the drilling shaft 10 in the forward or reverse direction via the drilling rod 1, so no hydraulic or electrical operating systems are required. Therefore, the expansion drilling device 200 can be constructed using only mechanical elements, and its structure is simple.

The upper expansion wing 11 and the lower expansion wing 12 share a support shaft 13 and are arranged so that they overlap along the axis 10c of the drilling shaft 10. The upper expansion wing 11 and the lower expansion wing 12 have similar structures, functions, etc., which is effective in improving the efficiency of expansion drilling work.

As shown in Figures 8 and 9, in the expansion drilling device 200, a nut 17 is fixed to the outer periphery of the bracket 16, closer to the drilling shaft 10 than the support shaft 13. The nut 17 is fixed so that its axis is parallel to the support shaft 13, and a synthetic resin expansion confirmation bolt 18 is threaded onto the nut 17.

When the upper expansion wing 11 and lower expansion wing 12 are in a reduced diameter state, the tip 18a of the expansion confirmation bolt 18 is separated from the upper expansion wing 11 and lower expansion wing 12, but the tip 18a of the expansion confirmation bolt 18 is located within the operating range when the upper expansion wing 11 and lower expansion wing 12 rotate to their expanded diameter state. Therefore, when the upper expansion wing 11 and lower expansion wing 12 rotate to their expanded diameter state, the tip 18a of the expansion confirmation bolt 18 is sheared.

That is, as shown in Figure 9, as the upper expansion wing 11 rotates to its expanded state, when the recess 11c of the upper expansion wing 11 passes under the nut 17, a shearing action occurs between the recess 11c and the nut 17, shearing the tip 18a of the expansion confirmation bolt 18. This shearing action also occurs in the lower expansion wing 12.

Therefore, after the enlargement excavation work is completed and the enlargement excavation device 200 is raised to the ground, visually checking for shearing of the expansion confirmation bolt 18 makes it possible to confirm whether the upper expansion wing 11 and the lower expansion wing 12 have expanded during the enlargement excavation work. This makes it possible to confirm whether a root protection bulb of the specified size has been formed at the tip of the pile hole H. By removing the expansion confirmation bolt 18 with its tip 18a sheared from the nut 17 and screwing a new expansion confirmation bolt 18 into the nut 17, the function as an expansion confirmation means is restored.

The aforementioned diameter expansion confirmation bolt 18 shown in Figures 2 and 3 is provided in the same manner as the nut 17 and diameter expansion confirmation bolt 18 shown in Figures 8 and 9, and exhibits the same effects as the diameter expansion confirmation bolt 18 in Figures 8 and 9.

After the expansion drilling operation is completed, the drilling rod 1 (see Figure 7) is rotated forward in the direction of arrow R, causing the upper expansion wing 11 and lower expansion wing 12 to return to the reduced diameter state shown in Figures 6 and 7, making it easy to pull up the expansion drilling device 200.

Next, another embodiment, the expansion drilling device 300, will be described with reference to Figure 10. However, parts of the expansion drilling device 300 that are common to the expansion drilling device 200 described above will be assigned the same reference numerals as those shown in Figures 6 to 9, and descriptions thereof will be omitted.

As shown in Figure 10, the expansion drilling device 300 has multiple conical bits 19 on the upper surface 11a of the upper expansion wing 11 and the lower surface 12b of the lower expansion wing 12. Each conical bit 19 is welded via a pedestal 19a.

The tips 19b of the multiple conical bits 19 on the upper surface 11a of the upper expansion wing 11 are inclined so that when the drilling shaft 10 rotates in the reverse direction of arrow L, they point upward along arrow L and away from the drilling shaft 10.

The tips 19b of the multiple conical bits 19 on the underside 12b of the lower expansion wing 12 are inclined so that when the drilling shaft 10 rotates in the reverse direction of arrow L, they point downward along arrow L and away from the drilling shaft 10.

As shown in Figure 10, by providing multiple conical bits 19 on the upper surface 11a of the upper expansion wing 11 and the lower surface 12b of the lower expansion wing 12, the expansion and contraction movements of the upper expansion wing 11 and the lower expansion wing 12 can be made faster and more reliable, which is also effective in improving the efficiency of expansion excavation work.

Note that the expansion drilling devices 100, 200, and 300 described based on Figures 1 to 10 are examples of expansion drilling devices according to the present invention, and the expansion drilling devices according to the present invention are not limited to the expansion drilling devices 100, 200, and 300 described above.

The excavation device according to the present invention can be widely used in fields such as civil engineering and construction as a device for excavating and enlarging the tip of a pile hole formed in the ground to form a root-hardening bulb.

1 Drilling rod 2, 21 Drive shaft 3, 23 Drilling blade 4, 14b Connector hole 10 Drilling shaft 10c Axis center 11 Expansion blade (upper expansion blade)
11a Upper surface 11b Protrusion 11c Recess 11d Tip 12 Lower expansion wing 12b Lower surface 13 Support shaft 14a, 22 Connector 16 Bracket 17 Nut 18 Expansion confirmation bolt 18a Tip 19 Conical bit 19a Base 19b Point 20 Drilling head 100, 200, 300 Expansion drilling device

Claims (4)

a drilling shaft that can be connected to the tip of the drilling rod so as to rotate integrally with the drilling rod;
A plurality of support shafts are arranged on the outer periphery of the drilling shaft, parallel to the axis of the drilling shaft, and equally spaced along the circumferential direction of the drilling shaft;
an expansion wing rotatably attached to the support shaft and having a protrusion on the base end side that protrudes in a direction away from the tip end,
During pile hole excavation work in which the drilling rod rotates forward, the expansion wing, which receives earth pressure, abuts against the drilling shaft, and the tip of the expansion wing maintains a reduced diameter state in which it is close to the drilling shaft,
During enlarged excavation work in which the drilling rod rotates in the reverse direction, the expansion wing rotates around the support shaft under the influence of earth pressure, and expands until the protrusion of the expansion wing abuts the outer peripheral surface of the drilling shaft , thereby supporting the reaction force of the earth pressure with the outer peripheral surface of the drilling shaft and maintaining the expanded diameter state. The expansion drilling device according to claim 1, wherein a plurality of the expansion wings are arranged so as to overlap along the axial direction of the drilling shaft. The expansion drilling device according to claim 1 or 2, further comprising an expansion confirmation member that is sheared when the expansion wing rotates to the expanded diameter state. The expansion drilling device described in any one of claims 1 to 3, wherein at least one conical bit is provided on at least one of the upper and lower surfaces of the expansion wing during expansion drilling operations.