Expanding Drilling Rig

Abstract

To provide an enlarging excavator having a simple structure composed only of mechanical elements, having high strength, and having a higher enlarging excavation rate than a conventional enlarging excavator.SOLUTION: An enlarging excavator 100 comprises a drilling shaft 10 that can be integrally connected to a tip of a drilling rod, a plurality of support shafts 13 that are arranged on an outer periphery of the drilling shaft 10, parallel to the axis 10c of the drilling shaft 10, and arranged at equal intervals along the circumferential direction of the drilling shaft 10, and enlarging blades 11 rotatably attached to each support shaft 13. During pile hole excavation work in which the drilling rod rotates forward in the direction of arrow R, the enlarging blade 11 that receives earth pressure maintains a reduced diameter state. During the enlarging excavation work in which the enlarging rod rotates in the direction of the arrow L in the opposite direction, the enlarging blade 11 receives earth pressure and rotates around the support shaft 13 to enlarge the diameter. In this state, the drilling shaft 10 and the plurality of enlarging blades 11 rotate in the direction of the arrow L to enlarge and drill the surrounding ground.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an expansion excavation device used in construction work for expanding and excavating the tip of a pile hole formed in the ground to form a root-hardening bulb portion. [Background technology]

[0002] Various structures and functions have been proposed for excavation expansion devices that expand and excavate the tip of a pile hole formed in the ground to form a root-hardening bulb portion. One example of a device related to the present invention is the "extraction expansion device" described in Patent Document 1.

[0003] 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 that are attached along the spiral of each drilling blade and are configured to be switchable between an expanded diameter state and a contracted diameter state.

[0004] 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, the soil pressure causes the expansion wings to be in a reduced diameter state, with most of them contained within the rotation path of the drilling wings. When the drilling rod is rotated backward, the soil pressure causes the expansion wings to swing around the pins and expand, protruding radially outward from the rotation path of the drilling wings. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-214366 Summary of the Invention [Problem to be solved by the invention]

[0006] 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, since the size of the expansion blades (the radial size of the rotation surface of the drilling rod) is smaller than that of the drilling blades, there is a problem in that the expansion drilling rate is low.

[0007] Furthermore, in the above-mentioned "expansion excavation device," if the size of the expansion wing is increased in order to increase the expansion excavation rate, the load applied to the vicinity of the bracket by earth pressure during the expansion excavation work becomes excessive, increasing the possibility of damage, and therefore, in reality, it is difficult to increase the expansion excavation rate by increasing the size of the expansion wing.

[0008] Therefore, the problem that the present 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. [Means for solving the problem]

[0009] 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.

[0010] In the expansion drilling device, a plurality of the expansion wings can be arranged so as to overlap along the axial direction of the drilling shaft.

[0011] The expansion drilling device may be provided with a diameter expansion confirmation member that is sheared when the expansion wing rotates to the diameter expanded state.

[0012] In the expansion drilling device, at least one conical bit can be provided on at least one of the upper surface and the lower surface of the expansion wing. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide an expansion drilling device which has a simple structure composed only of mechanical elements, is strong, and has a higher expansion drilling rate than conventional expansion drilling devices. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a partially omitted front view showing an expansion drilling device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a partially omitted horizontal cross-sectional view taken along line AA in FIG. 1, showing the expansion wing in a contracted state. [Figure 3] FIG. 2 is a partially omitted horizontal cross-sectional view taken along line AA in FIG. 1, showing the expansion wing in a state where its diameter is expanded. [Figure 4] 2 is a partially omitted front view showing a state in which a drilling head is being connected to the expansion drilling device shown in FIG. 1. FIG. [Figure 5] 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). [Figure 6] 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. [Figure 7] FIG. 7 is a partially omitted vertical cross-sectional view showing the expansion drilling device shown in FIG. 6 in use (with the expansion wings contracted). [Figure 8] 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. [Figure 9] FIG. 9 is a partially omitted perspective view showing the vicinity of a diameter expansion confirmation member in FIG. 8. [Figure 10]FIG. 10 is a partially omitted perspective view showing an expansion drilling device according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] An expansion drilling device 100 according to an embodiment of the present invention will be described below with reference to Figures 1 to 5. The expansion drilling device 100 shown in Figures 1 to 3 comprises, as shown in Figure 5, a drilling rod 1 having 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 provided on 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 arranged at equal intervals along the circumferential direction of the drilling shaft 10, and expansion blades 11 rotatably attached to each support shaft 13.

[0016] As shown in Fig. 1, each support shaft 13 is fixed at a position away from the outer circumferential surface 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 blade 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 a protrusion 11b protruding in a direction away from the tip 11d and a recess 11c adjacent to the protrusion 11b and recessed in a direction toward the tip 11d. The expansion blades 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 blades 11 are not limited to the configuration shown in Figs. 2 and 3.

[0017] An expansion confirmation bolt 18 is arranged on the outer periphery of the multiple brackets 16, closer to the drilling shaft 10 than the support shaft 13. The structure and function of the expansion confirmation bolt 18 and its vicinity will be described in detail later with reference to Figures 8 and 9.

[0018] As shown in Figure 1, a hexagonal prism-shaped connector 14a protrudes from the upper end of the drilling shaft 10 for connecting to the lower end portion 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 a connector 22 protruding from the upper end of the drive shaft 21 of the drilling head 20 shown in Figure 4 can be inserted.

[0019] When using the enlargement drilling device 100 shown in Fig. 1, the drilling head 20 is connected to the lower end side of the enlargement drilling device 100 as shown in Fig. 4. The drilling head 20 comprises a cylindrical drive shaft 21, a hexagonal column-shaped connector 22 protruding from the upper end side of the drive shaft 21, and a spiral drilling blade 23 provided on the outer periphery of the drive shaft 21. The connector 22 on the upper end side of the drilling head 20 is fitted into the connector hole 14b on the lower end side of the drilling shaft 10 of the enlargement drilling device 100 and fixed by a predetermined fixing means, whereby the enlargement drilling device 100 and the drilling head 20 are connected together.

[0020] Next, as shown in Figure 4, the enlargement 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 as to rotate integrally with the drilling rod 1. Specifically, the connector 14a on the upper end side of the drilling shaft 10 of the enlargement drilling device 100 is fitted 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 with the enlargement drilling device 100 and the drilling head 20. As a result, the enlargement drilling device 100 and the drilling head 20 are connected to the drilling rod 1 so as to rotate integrally with the drilling rod 1.

[0021] Here, the functions, actions, and effects of the expansion wing 11 constituting the expansion drilling device 100 will be described with reference to FIGS.

[0022] As shown in Fig. 5, during pile hole excavation work, the drilling rod 1 is rotated forward in the direction of the arrow R. At this time, as shown in Fig. 2, the tip end 11d of the expansion blade 11, which is subjected to earth pressure, is kept 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 the arrow R, pile hole excavation work can be carried out smoothly.

[0023] On the other hand, during enlarged excavation work, the drilling rod 1 is rotated in the reverse direction in the direction of the arrow L. At this time, as shown in Fig. 3, the multiple expansion wings 11 that receive earth pressure rotate around the support shafts 13, and expand until the protrusions 11b of the expansion wings 11 abut against the outer periphery of the drilling shaft 10, and are maintained in an expanded diameter state in the shape of a shuriken, as shown in Fig. 3. Therefore, the multiple expansion wings 11 that rotate in the direction of the arrow L with a larger rotation radius than the excavation blades 23 (see Fig. 5) excavate the ground around the expansion wings 11 of the pile hole H formed in the ground shown in Fig. 5, and form a foot protection bulb (not shown) with an inner diameter larger than that of the pile hole H.

[0024] As described above, the expansion wing 11 of the expansion drilling device 100 shown in Fig. 3 rotates in the direction of arrow L with a large rotation radius to expand and excavate the ground around the pile hole H (see Fig. 5), thereby enabling a higher expansion excavation rate than conventional expansion drilling devices. In addition, when the expansion wing 11 rotates in the direction of arrow L to excavate the ground, the reaction force of the earth pressure generated in 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 exhibiting high strength despite its simple structure.

[0025] Furthermore, as shown in FIG. 3, the support shaft 13 is positioned away from the outer periphery of the drilling shaft 10, so that the soil and sand accumulated between the support shaft 13 and the reaction point (the protrusion 11b) does not get caught when the expansion blade 11 expands, ensuring smooth expansion operation.

[0026] After the enlargement excavation work is completed, when the drilling rod 1 (see Figure 5) is rotated forward in the direction of arrow R, the multiple expansion wings 11 that have received earth pressure each return to the contracted diameter state shown in Figures 1 and 2, so that the enlargement excavation device 100 and the drilling head 20 can be easily pulled up to the ground together with the drilling rod 1.

[0027] The expansion wing 11 constituting the expansion drilling device 100 expands or contracts in diameter simply by rotating the drilling shaft 10 forward or backward via the drilling rod 1, so no hydraulic or electrical operating system is required. Therefore, the expansion drilling device 100 can be constructed only with mechanical elements, and the structure is simple.

[0028] Next, another embodiment of the excavation device 200 will be described with reference to Figures 6 to 9. In the excavation device 200, parts common to the excavation 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.

[0029] Figure 6 shows the state in which the drilling head 20 is 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 at 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 on top of the other along the axis 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.

[0030] The upper and lower expansion wings 11 and 12 can rotate around support shaft 13 without interfering with each other. The shapes and functions 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.

[0031] 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 used by connecting it to the tip of the drilling rod 1 so that it rotates integrally with the drilling rod 1.

[0032] 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 reverse or forward direction via the drilling rod 1. This eliminates the need for hydraulic or electrical operating systems. Therefore, the expansion drilling device 200 can be constructed using only mechanical elements, and its structure is simple.

[0033] The upper expansion wing 11 and the lower expansion wing 12 share a support shaft 13 and are arranged so as to overlap along the axis 10c of the drilling shaft 10. Since the upper expansion wing 11 and the lower expansion wing 12 have similar structures, functions, etc., they are effective in improving the efficiency of expansion drilling work.

[0034] 8 and 9, in the expansion drilling device 200, a nut 17 is fixed to the outer periphery of the bracket 16 at a portion closer to the drilling shaft 10 than the support shaft 13. The nut 17 is fixed so that its axial direction is parallel to the support shaft 13, and a synthetic resin expansion confirmation bolt 18 is screwed onto the nut 17.

[0035] When the upper expansion wing 11 and the lower expansion wing 12 are in the reduced diameter state, the tip 18a of the diameter expansion confirmation bolt 18 is separated from the upper expansion wing 11 and the lower expansion wing 12, but the tip 18a of the diameter expansion confirmation bolt 18 is located within the operating range when the upper expansion wing 11 and the lower expansion wing 12 rotate to the expanded diameter state. Therefore, when the upper expansion wing 11 and the lower expansion wing 12 rotate to the expanded diameter state, the tip 18a side of the diameter expansion confirmation bolt 18 is sheared.

[0036] 9, as the upper expansion wing 11 rotates to the expanded state, when the recess 11c of the upper expansion wing 11 passes under the nut 17, the tip 18a of the expansion confirmation bolt 18 is sheared off by a shearing action that occurs between the recess 11c and the nut 17. This shearing action also occurs in the lower expansion wing 12.

[0037] Therefore, after the enlargement excavation work is completed and the enlargement excavation device 200 is raised to the ground, by visually checking whether the upper expansion wing 11 and the lower expansion wing 12 have expanded during the enlargement excavation work, it is possible to check whether a root protection bulb of a predetermined size has been formed at the tip of the pile hole H. If the expansion confirmation bolt 18 with the sheared tip 18a side is removed from the nut 17 and a new expansion confirmation bolt 18 is screwed onto the nut 17, the function as the expansion confirmation means is restored.

[0038] In addition, the expansion confirmation bolt 18 shown in Figures 2 and 3 is provided in the same manner as the nut 17 and expansion confirmation bolt 18 shown in Figures 8 and 9, and exerts the same effect as the expansion confirmation bolt 18 in Figures 8 and 9.

[0039] After the expansion drilling operation is completed, by rotating the drilling rod 1 (see Figure 7) in the direction of arrow R, the upper expansion wing 11 and the lower expansion wing 12 return to the reduced diameter state shown in Figures 6 and 7, making it easy to pull up the expansion drilling device 200.

[0040] Next, based on Figure 10, we will explain another embodiment of the expansion excavation device 300, but parts of the expansion excavation device 300 that are common to the expansion excavation device 200 described above will be assigned the same reference numerals as those shown in Figures 6 to 9 and will not be explained further.

[0041] 10, in the expansion drilling device 300, a plurality of conical bits 19 are provided on the upper surface 11a of the upper expansion wing 11 and the lower surface 12b of the lower expansion wing 12. Each of the conical bits 19 is welded via a pedestal 19a.

[0042] The tip ends 19b of the multiple conical bits 19 on the upper surface 11a of the upper expansion wing 11 are arranged at an angle so that when the drilling shaft 10 rotates in the reverse direction of the arrow L, they face upward along the arrow L and away from the drilling shaft 10.

[0043] The tip ends 19b of the multiple conical bits 19 on the lower surface 12b of the lower expansion wing 12 are arranged at an angle so that when the drilling shaft 10 rotates in the reverse direction of the arrow L, they point downward along the arrow L and away from the drilling shaft 10.

[0044] As shown in FIG. 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.

[0045] The expansion drilling devices 100, 200, and 300 described based on Figures 1 to 10 are examples of the expansion drilling device according to the present invention, and the expansion drilling device according to the present invention is not limited to the expansion drilling devices 100, 200, and 300 described above. [Industrial Applicability]

[0046] The enlarged excavation device according to the present invention can be widely used in fields such as civil engineering and construction as a device for carrying out construction work to enlarge and excavate the tip of a pile hole formed in the ground to form a root-hardening bulb portion. [Explanation of symbols]

[0047] 1 drilling rod 2,21 Drive shaft 3,23 Drilling blade 4,14b Connector hole 10 Drilling shaft 10c axis center 11. Expansion wing (upper expansion wing) 11a Top side 11b Protrusion 11c Recess 11d Tip 12 Lower expansion wing 12b Bottom side 13 Spindle 14a,22 connector 16 Bracket 17 Nut 18 Expansion confirmation bolt 18a Tip 19 Conical Bit 19a Pedestal 19b Tip 20 Drilling Head 100, 200, 300 Expansion Drilling Rig

Claims

1. 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.

2. 2. 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.

3. 3. The expansion drilling device according to claim 1, further comprising a diameter expansion confirmation member that is sheared when the expansion wing rotates to the expanded diameter state.

4. 4. The expansion drilling device according to claim 1, wherein at least one conical bit is provided on at least one of the upper surface and the lower surface of the expansion wing during expansion drilling work.

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