JPH0434233Y2 - - Google Patents

Description

[Detailed description of the invention] "Industrial application field" This invention relates to an enlarged drilling device for the bit part at the tip of a drilling rod, mainly for use in pre-boring type embedded pile construction methods such as the Rodex construction method. .

``Problems to be solved by conventional techniques and ideas'' As shown in Fig. 5, this type of conventional expanding drilling equipment has upper and lower brackets B on the upper outer periphery of a cylindrical bit body A connected to the drilling rod. An enlarged blade D whose base end is rotatably attached to a vertical shaft C supported by
is provided, and by rotating the excavation rod from the base end to the distal end of this enlarged blade D (reverse rotation), the earth and sand riding on the screw excavation blade E below it flows back to the inner surface of the enlarged blade, increasing earth pressure. acts, or the tip of the enlarged blade D bites into the ground around the drilling hole, and due to the resistance, the enlarged blade is rotated in the direction of expanding outward, thereby making it possible to perform enlarged excavation. By rotating toward the rear end of D (forward rotation), normal excavation by the excavating blade E becomes possible, and earth pressure acts on the outer surface of the enlarged blade D to close the enlarged blade D inward. (Utility Model Publication No. 60-91691, Publication of Utility Model Application Publication No. 57-8)
(See Publication No. 16948 and Special Publication No. 56-596).

However, with such a conventional expanding blade D, it is expected that the blade will spread naturally due to earth pressure resistance, so if it is immediately after excavating a clay layer or if the supporting layer is solidified silt, etc., the head part of the bit body A will have viscosity. There was a drawback that the soil with a high height was stuck and formed into a dango-like shape, and even if the excavation rod was reversed in this state, there was no backflow of soil and the expanding blade D could not be expanded.

In addition, in conventional expansion excavation equipment, the expansion blade D is expanded by earth pressure resistance, so the area that receives the earth pressure of the expansion blade D needs to be widened, and the resistance during expansion excavation is correspondingly large, which increases the rotational drive of the excavation rod. We also need to increase our strength.

Therefore, conventionally, a connecting tube with a spiral threaded hole attached to the tip of the piston rod of a hydraulic cylinder installed around the tip of the auger shaft is moved forward and backward, and the excavator blade rotating shaft with the tip screw inserted into the connecting tube is adjusted in the correct direction. There is also a known device that rotates in the opposite direction and expands and contracts by rotating an expanding digging blade fixed to it.
(Japanese Patent Publication No. 57-53514), this expansion excavation equipment is mechanically complex because it requires a hydraulic drive mechanism and hydraulic piping for expanding and contracting the expansion excavation blade in addition to the rotary power mechanism such as the auger shaft. However, the overall size is large, the manufacturing cost is high, and there are problems such as the possibility that sand and gravel may get caught between the excavator blade rotating shaft and the connecting cylinder portion with a spiral screw hole, making the rotating shaft unable to rotate.

Furthermore, there has been a known device in which the expanding blade is rotated for expansion and contraction using a gear mechanism that is provided on the excavating rod and the expanding blade rotating shaft and that mesh with each other (Japanese Patent Laid-Open No. 1983-1989-1).
37031, Japanese Patent Application Laid-Open No. 55-19370), it is easy for sand and gravel to get stuck between the gears, making them unrotatable.
In order to prevent this, a device in which the periphery of the gear is hermetically covered with a casing has problems such as an extremely complicated structure and an enormous manufacturing cost.

"Means for solving the problem" This invention aims to solve the above-mentioned conventional problem.
A bit body 3 with excavation blades 4 attached to its outer periphery is attached to the lower end of the joint rod 2 so as to be rotatable at a predetermined angle, and the middle part of the bit body 3 is rotatable at a predetermined angle around a vertical shaft 6 supported by upper and lower brackets 5, 5 on the outer periphery of the bit body 3. An enlarged excavation device is proposed, which is provided with an enlarged blade 7 attached to the enlarged blade 7, a pressing knob 10 whose distal end protrudes toward the rear end of the enlarged blade 7, and whose proximal end is fixed to the outer periphery of the joint rod 2. It is.

``Operation'' First, when performing normal diameter-reducing excavation, the excavator rod 1 is rotated in the forward rotation direction, the pressing knob 10 is locked to the stopper 8, and the bit body 3 is rotated together with the joint rod 2. Excavation is performed by the excavation blade 4.

In this state, earth pressure acts on the outside of the enlarged blade 7, so that the enlarged blade 7 is pressed against the circumferential surface of the bit body 3 and closed.

Next, when performing expanded excavation, the excavation blade 4
bit body 3 by digging into the ground at the bottom of the drilling hole.
The rotation of the expanding blade 7 is restrained, and then the drilling rod 1 is reversed, and the tip of the pressing notch 10 is pushed out toward the rear end of the expanding blade 7 to press it.
The excavator rod 1 is forcibly rotated outward to be expanded, and the excavation rod 1 continues to be rotated in the reverse direction to perform expanded excavation with the expanded enlarging blade 7.

In this case, immediately after excavating a clay layer or when the supporting layer is made of consolidated silt, even if highly viscous soil is stuck to the head of the bit body 3 and forms a lump shape, the excavation blade 4 can be moved to the ground below. A pressing knob 10 is pushed into a mountain to restrain the rotation of the bit body 3, and then rotates following the reversal of the drilling rod 1.
Since the enlarging blade 7 is pressed and forcibly expanded, the enlarging blade 7 can be reliably expanded.

After enlarged excavation, when retracting and closing the expanded enlarging blade 7, the excavating blade 4 bites into the ground at the bottom of the drilling hole to restrain the rotation of the bit body 3, and then the excavating rod 1 is rotated in the forward direction to remove the surrounding area. "Example" in which the expanding blade 7 is rotated inward by the earth pressure of earth and sand to contract and close it.The following describes an example of this invention shown in the drawings. A bit body 3 is attached to the bit body 3 so as to be rotatable by a predetermined angle, and a spiral excavation blade 4 is attached to the outer periphery of the bit body 3 for performing normal excavation by rotating the excavation rod 1 in the normal direction.

A vertical shaft 6 is provided on the upper outer periphery of the bit body 3 and is vertically supported by upper and lower brackets 5, 5.
An enlarged blade 7 is rotatably attached to the vertical shaft 6 at the intermediate portion thereof, and an enlarged blade 7 is provided at a predetermined interval from the mounting position of the enlarged blade 7 in the normal rotation direction of the excavation rod 1 to regulate the rotation angle of the bit body 3. A stopper 8 is attached.

The expanding blade 7 is normally stationary in a state where the tip of the expanding blade 7 faces in the opposite direction (reverse direction) to the forward rotation direction of the drilling rod 1 and is fitted to the periphery of the bit body 3.
When the rear end is pressed in the reverse direction of the drilling rod 1, it rotates so as to expand outward from the bit body 3, and at the maximum expansion position, stoppers 9 are provided on the upper and lower brackets 5, etc. to engage the front or rear end of the expansion blade 7 to restrict further rotation.

A pressing notch 10 is fixed at its upper base end to the outer circumference of the lower part of the joint rod 2, and the lower part is inserted between the enlarged blade 7 and the stopper 8 on the outer circumference of the bit body 3 with its tip facing the rear end of the enlarged blade 7. When the joint rod 2 is rotated in the reverse direction together with the excavation rod 1, the tip of the pressing notch 10 presses the rear end of the enlarged blade 7 and removes the enlarged blade 7, as shown in FIGS. 2 and 4. The enlarged blade 7 is forcibly rotated in the direction of expansion.
Accordingly, the excavating rod 1 continues to rotate in the reverse direction to carry out enlarged excavation.

In addition, along with drilling rod 1, joint rod 2 is also provided.
When the bit body 3 is rotated in the normal rotation direction, the tip of the press knob 10 is separated from the rear end of the enlarged blade 7 and the rear end is stopped by the stopper 8, as shown in FIGS. At the same time, the excavating blade 4 rotates in the normal rotation direction, and the excavating blade 4 performs ordinary excavating.

In this case, in order to rotate the bit body 3 together with the joint rod 2 in the forward rotation direction, the press knob 10 was locked to the stopper 8, but it is also possible to fix the stopper to the joint rod 2 separately from the press knob 10. This may be secured to a stopper 8 of the bit body 3.

``Effect of the invention'' As described above, according to this invention, by rotating the drilling rod and the joint rod connected to it in the reverse direction with the drilling blade biting into the ground at the bottom of the borehole, the drilling blade can be rotated in the opposite direction. The knob rotates toward the rear end of the enlarging blade and presses the rear end of the enlarging blade.
The expanding blade can be rotated using the principle of a lever to forcibly and reliably spread outwards, and can be used to remove highly viscous soil at the head of the bit body immediately after digging through a clay layer or when the supporting layer is solidified silt. Even if the material is stuck and becomes lumpy, it is possible to reliably spread the enlarging blade and perform enlarged excavation.

In addition, since the expanding blade does not expand due to earth pressure resistance, by reducing the area of the expanding blade and reducing the earth pressure resistance during expanded excavation, the excavation rod can be rotated with a small rotational driving force, making it more efficient. It is true.

Furthermore, it is mechanically extremely simple and compact, does not cause differential failure due to sand and gravel getting stuck, and can be manufactured economically at low cost.

[Brief explanation of the drawing]

Figure 1 is a front view showing an embodiment of this invention, Figure 2 is a front view showing an embodiment of this invention.
3 is a front view showing the state during normal excavation, FIG. 4 is a front view showing the state during enlarged excavation, and FIG. 5 is a front view of the conventional enlarged bit. 1...Drilling rod, 2...Joint rod,
3...Bit body, 4...Drilling blade, 5...Bracket, 6...Vertical shaft, 7...Enlarged blade, 8...Stopper, 9...Stopper, 10...Press notch.

Claims (1)

[Scope of utility model registration request] A bit body with a digging blade attached to its outer periphery is attached to the lower end of the joint rod so as to be rotatable at a predetermined angle, and an enlarged blade is provided on the outer periphery of the bit body, the middle part of which is attached to a vertical shaft supported by upper and lower brackets so as to be rotatable at a predetermined angle. . An enlarged excavation device, characterized in that the enlarged blade is provided with a pressing knob whose distal end protrudes toward the rear end and whose proximal end is fixed to the outer periphery of the joint rod.