JPH0432188B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a drilling bit device used for bottom-expanding excavation in a cast-in-place bottom-expanding pile of the earth drilling method.

[Prior art]

As shown in Fig. 4, the conventional earth drill type bottom-expanding drilling equipment has a drilling bit 1 mounted on a vertical shaft 4.
The method of expanding by rotating around a and 4b, and the fifth
As shown in the figure, there is a method in which an upper expanding digging bit 6 having a downward opening link mechanism and a lower expanding digging bit 7 having a vertical hinge mechanism and opening laterally are individually expanded.

[Problem that the invention seeks to solve]

When using the above-mentioned conventional bottom-expanding excavation equipment, there are the following problems.

The method shown in Fig. 4 requires a complicated link mechanism with hydraulic cylinders 5 in the horizontal direction in order to expand and contract multiple expanding excavation bits in synchronization. Since it constantly changes depending on the opening degree of the bit 1, it is difficult to perform efficient and stable excavation in the reverse sloped part at the top of the enlarged bottom shape, where the wall of the excavation hole is most unstable. On the other hand, in the method shown in FIG. 5, the bottom expanding mechanism becomes complicated because the upper and lower bits are individually operated by the respective hydraulic cylinders 9a and 9b.
It is difficult to excavate the entire surface of an expanded bottom shape at the same time. In practical use, after the excavation work of the upper expansion bit 6 is completed, the excavation work of the lower expansion bit 7 must be started, which greatly reduces excavation or work efficiency. Furthermore, in order to smoothly join the excavation trajectories of the upper expanding bit 6 and the lower expanding bit 7, the expanding operation of the lower expanding bit 7 must be controlled with high precision.

The present invention solves the problems of the prior art described above,
The present invention provides an earth drill type rotary drilling bit device for bottom expansion that realizes highly efficient and stable drilling work.

[Means for solving problems]

A drill pipe is connected to the lower end of the earth drill machine's Kerry bar, and an upper drilling bit whose upper end is fixed with a pin shaft is suspended from the top of the drill pipe, and the upper drilling bit is opened downward in an umbrella shape by the hydraulic pressure of a hydraulic cylinder. In addition to providing a link mechanism and a synchronization ring, an earth and sand bucket is provided at the bottom of the drill pipe, which is connected to the drill pipe so that it can swing around the drill pipe as a rotation axis, and the earth and sand bucket is opened laterally with a hinge whose side part is perpendicular to the earth and sand bucket. Attach the lower expanding drilling bit constructed as above, and connect the lower end of the upper expanding drilling bit and the upper part of the lower corner drilling bit with a vertically slidable pin shaft to perform the expansion/contraction operation of the upper expanding drilling bit and the lower expanding drilling bit. By interlocking the opening and closing operations of the bit, the kelly bar and drill pipe are rotated in the drilling direction, and the operation trajectory is determined by the shape of the upper expanding drilling bit and the link structure.
The entire surface of the ground is excavated in a shape determined by the shape of the lower expanding excavation bit and the motion locus of the hinge structure, and the excavated soil is taken into the earth and sand bucket at the front of the lower expanding excavating bit to form a predetermined expanded bottom shape. It is characterized by

[Effect]

Since the present invention has the above-mentioned configuration, the upper expanding drilling bit and the lower expanding drilling bit can be connected by the connecting structure at the pin shaft of the upper expanding drilling bit and the lower expanding drilling bit, and by the rocking movement of the earth and sand bucket around the drill pipe axis. are expanded in conjunction with each other to excavate the entire surface of the expanded bottom shape at the same time. Further, the entire operation of the drilling bit device is performed only by the action of a simple downward opening link mechanism and a hydraulic cylinder provided on the upper expanding drilling bit.

The upper expanding drilling bit protrudes radially around the drill pipe, and the upper expanding drilling bit penetrates into the ground while always maintaining a constant cutting angle.

As a result, an enlarged bottom shape with a smooth hole wall surface is uniquely determined, and highly efficient and stable excavation work is realized.

〔Example〕

Examples shown in the drawings will be described below.

1 and 2 show the structure and function of a drilling bit device according to the present invention. Fig. 1 shows the stored state of the bottom-expanding drilling bit, that is, the state before the start of bottom-expanding excavation, and Fig. 2 shows the expanded state of the bottom-expanding drilling bit,
In other words, it represents the state at the end of bottom-expanding excavation.

The upper end of the drill pipe 23 of the drilling bit device is connected to the Kelly bar of the earth drill machine by a connecting pin 24, and the drilling bit device is suspended from the Kelly bar.
To surely transmit the drilling rotational force of Kerryba to a drill pipe 23. A stabilizer 20 is installed on the upper part of the drill pipe 23 to enhance stability of drilling.

The upper expanding drilling bit 17 is composed of four wings.
A synchronizing ring 22 is provided which is fitted with the synchronous ring 22 and slides in the vertical direction by the operating force of the hydraulic cylinder 19, and the lower part of the upper expanding drilling bit 17 is connected with the connecting link 21 via the synchronizing ring and the pin shaft. drilling bit 17
Forms a link mechanism that opens downward using hydraulic pressure. Accordingly, as the pair of hydraulic cylinders 19 disposed on the sides of the drill pipe 23 expand and contract, the synchronizing ring 22 moves up and down, expanding and contracting the four-winged upper expanding drilling bit 17 in the radial direction with respect to the drill pipe axis. At the bottom of the drill pipe 23, there is provided an earth and sand bucket 11 connected to the drill pipe 23 so that it can swing around the drill pipe 23 as a rotation axis, and furthermore, the earth and sand bucket is configured so that a part of the side surface thereof can be opened laterally by a vertical hinge 14. A two-winged lower expanding drilling bit 13 is attached. Note that a sliding key portion 22a is provided between the synchronization ring 22 and the drill pipe 23, so that not only the drilling rotational force is directly transmitted from the drill pipe 23 to the upper expanding drilling bit 17, but also the synchronization ring 2
2 and the connecting link 21 as well.

Of the four-winged upper expanding bit 17, a swing pin 16 that can rotate around a vertical axis and slide vertically is attached to the lower end of the two opposing upper expanding bits 17. 13, and the upper expansion drilling bit 1
7 and the lower expanding drilling bit 13 are connected to each other. Therefore, as the opening/closing shaft 15 is extended in the horizontal direction as the upper expanding digging bit 17 expands, the expanding/retracting action of the hydraulic cylinder 19 causes the upper expanding digging bit 17 to expand.
and the lower expansion/excavation bit 13 are simultaneously linked and expanded/contracted. Note that the expansion and contraction of the hydraulic cylinder 19 is operated from an operation panel on the ground.

The drilling rotational force is provided by the drill pipe 23 and the connecting pin 2.
6. It is transmitted to the earth and sand bucket 11 through the synchronization ring 22, the connection link 21, the upper expansion bit 17, the swing pin 16, the opening/closing shaft 15, the lower expansion bit 13, and the hinge 14.

FIG. 3 shows the two-dimensional movement of the swing pin 16 attached to the lower end of the upper expanding bit 17, the lower expanding bit 13, and the earth and sand bucket 11. FIG. 3A shows the case where the earth and sand bucket 11 is fixed to the drill pipe 23. Since the position of the hinge 14 of the lower expanding drilling bit 13 cannot be moved, the swing pin 16 and Opening/closing shaft 1
The position of 5 is shifted. Therefore, in Figure 3B, Figure 3A
In order to eliminate the misalignment 27 between the swing pin 16 and the opening/closing shaft 15, the drill pipe 23 and the sand bucket 1 are
1 is connected by a swing shaft 18, and as the swing pin 16 is extended in the radial direction, the rock bucket 1 is connected by the swing shaft 18.
1 around the axis of the drill pipe by a predetermined swing angle 28 times to shift the hinge 14 in the drilling rotation direction to the hinge position 14a at the time of expansion, and then lower the lower expansion drilling bit 13.
open smoothly. In addition, the hydraulic cylinder 19 in FIG.
By contracting the upper expanding excavation bit 17, the earth and sand bucket 11 exhibits a reverse swinging rotational motion, and the lower expanding excavation bit 13 closes. Due to this mechanism, the operating trajectory 29 of the tip 13a of the lower drilling bit 13 exhibits a gentle arc shape extending approximately in the radial direction, and closely follows the operating trajectory of the upper drilling bit 17 expanding in the radial direction to achieve a predetermined bottom expansion. A shape is formed. Incidentally, even if the earth and sand bucket 11 is swung around the axis of the drill pipe, there will be no problem in terms of excavation work or structure.

For excavation, use the top expansion drilling bit 17 on the top of the bottom expansion shape.
By protruding in the radial direction of the excavation rotation, the reverse slope portion is excavated according to the downward opening angle of the upper expanding excavation bit 17 while keeping the cutting angle of the excavation bit relative to the ground constant at an optimal angle. on the other hand,
The lower part expanding excavation bit 13 not only excavates the lower part of the expanded bottom shape, but also functions as a scraper to guide the excavated earth and sand into the inside of the excavated earth and sand bucket 11.
The excavated earth and sand at the bottom of the pile, which has spread further, is collected into the earth and sand bucket 11. And upper expansion drilling bit 1
While closing the lower expanding excavation bit 13 together with 7, the excavated earth and sand are surely taken into the earth and sand bucket 11.

After excavating the capacity of the earth and sand bucket 11, the excavation bit device is raised above the ground, and the bottom plate opening/closing lever 25 is operated to open the bottom plate 12 downward to discharge the excavated earth and sand, sequentially until the bottom is expanded to a predetermined bottom diameter. Repeat drilling.

In the above embodiment, the upper expanding drilling bit is 4
The use of wings increases the stability of the equipment during excavation compared to the conventional technology with a two-wing configuration shown in Figs. 4 and 5, which is advantageous for pile quality.
Of course, the object of the present invention can also be achieved even if the upper expanding drilling bit has two wings.

〔Effect of the invention〕

By using the expanded bottom drilling bit device of the present invention, it is possible to excavate the entire surface of the expanded bottom shape at the same time, and always maintain the optimal cutting angle for the reverse slope at the top of the expanded bottom shape, where the wall of the borehole is most unstable. Since the drilling bit can penetrate into the ground while keeping the drilling constant, highly efficient and stable excavation can be achieved. Also,
Since the bottom expanding mechanism is simple, maintainability and durability are excellent, and the device is very easy to operate and control.

[Brief explanation of drawings]

Fig. 1A is a side view of the excavation bit in a stored state showing an embodiment of the present invention, Fig. 1B is the bottom of the previous figure, Fig. 2A is a side view of the excavation bit when it is expanded, B
is a cross-sectional view taken along the line - in the previous figure, Figure 3A is a bottom view for explaining the state of the drilling bit when the drill pipe and earth and sand bucket are fixed, and Figure 3B is a diagram showing how the earth and sand bucket is shaken around the axis of the drill pipe. FIG. 6 is an explanatory bottom view of the state of the drilling bit when it rotates. Fig. 4 is an explanatory side view of a conventional drilling rig that expands the drilling bit by rotating it around a vertical axis, and Fig. 5 is an explanatory side view of a conventional drilling rig that expands the upper and lower drilling bits individually. It is a diagram. 11 is the earth and sand bucket, 12 is the bottom plate, 13 is the lower expanding excavation bit, 13a is the tip of the lower expanding excavating bit,
14 is the hinge, 14a is the hinge position when expanded, 1
5 is an opening/closing shaft, 16 is a swing pin, 17 is an upper expansion drilling bit, 18 is a swing shaft, 19 is a hydraulic cylinder, 2
0 is a stabilizer, 21 is a connecting link, 22 is a synchronization ring, 23 is a drill pipe, 24 is a connecting pin, 25 is a bottom plate opening/closing lever, 26 is a connecting pin, 2
7 is the positional deviation between the opening/closing shaft and the swing pin, 28 is the swing angle, and 29 is the operating trajectory of the tip of the lower expanding drilling bit.

Claims (1)

[Claims] 1. When drilling a cast-in-place expansion pile to expand the shape of the pile tip using the earth drilling method, a drill pipe is connected to the lower end of the Kerry bar of the earth drill machine, and the upper end is fixed to the top of the drill pipe with a pin shaft. In addition to providing a link mechanism and a synchronization ring that allow the bit to hang down and open the upper expanding drilling bit downward in an umbrella shape using the hydraulic pressure of a hydraulic cylinder,
An earth and sand bucket is attached to the bottom of the drill pipe so that it can swing around the drill pipe as a rotating shaft.
A lower expanding excavation bit is attached to the earth and sand bucket so that a part of the side surface can be opened laterally by a vertical hinge, and the lower end of the upper expanding excavating bit and the upper part of the lower expanding excavating bit are slidable in the vertical direction. Connected by a pin shaft, the expanding/retracting operation of the upper expanding drilling bit and the opening/closing operation of the lower expanding drilling bit are linked, and the kelly bar and drill pipe are rotated in the drilling direction, and the operation trajectory is determined by the shape of the upper expanding drilling bit and the link structure. The entire surface of the ground is excavated in a shape determined by the shape of the lower expanding excavation bit and the motion locus of the hinge structure, and the excavated soil is taken into the earth and sand bucket at the front of the lower expanding excavating bit to form a predetermined expanded bottom shape. An earth drill type rotary drilling bit device for bottom expansion, which is characterized by: