JPH116381A - Enlargement head for excavation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To excellently perform preparation of a bulb by surely widening an enlargement blade at the time of enlarging excavation. SOLUTION: An enlargement head for excavation is provided with an enlargement head body 6 vertically and movably connected on the lower end of an excavation rod 2 over a required stroke for the rod. The enlargement blade 12 is expandably provided on the lower outer peripheral part of the enlargement head body 6 in a horizontal plane, when the excavation rod 2 is lifted for the enlargement head body 6, it is connected thereto, and the enlargement blade 12 is expanded more outward than the outside diameter of the excavation rod 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an enlarged head in an excavator.

[0002]

2. Description of the Related Art Conventionally, when constructing a pile in the ground or constructing a ready-made hollow pile, a method of forming a bulb having a diameter larger than that of the pile with a mortar at the lower end of the pile and using the pile as a foundation is known. Is being done.

[0003] As means for forming the above-mentioned bulbs, an enlarged head having an enlarged blade is attached to the lower end of a drilling rod, and enlarged and dug by this enlarged head to produce a bulb.

In the conventional enlargement head, a pair of enlargement blades are pivotally supported on a drilling head connected to a lower end of the drilling rod at a position symmetrical on the diameter line in a substantially horizontal plane, and the drilling rod is rotated in a reverse direction. The blade is turned so that it protrudes due to the resistance of the earth and sand, and the reverse rotation causes the ground to be excavated, or Japanese Utility Model No. 58-17835.
As disclosed in Japanese Unexamined Patent Publication, there is a method in which the expanding blade is provided with a spreading behavior by a spring, and the diameter of the expanding blade is reduced by using an inner peripheral surface of a hollow pile.

[0005]

However, in the former method, since the enlarging blade is housed within the outer diameter of the enlarging head when the diameter is reduced, the resistance of the earth and sand cannot be effectively received. However, there is a problem that the operation does not protrude outwardly and the reliability of the operation is lacking. This is remarkable when excavating highly self-sustaining ground.

In the latter method, since the inner peripheral surface of the hollow pile is used when the diameter of the enlarged blade is reduced, the method is used for a method of constructing a hollow pile after excavation without excavating the hollow pile. There was a problem that can not be.

Further, in the former case, the diameter of the enlarged blade is reduced at the time of drawing after the work is completed, so it was not possible to confirm whether or not the enlarged blade was expanded at the time of bulb formation.

[0008]

SUMMARY OF THE INVENTION According to the present invention, it is possible to satisfactorily open a magnifying blade by expanding a magnifying blade at the time of magnifying digging, thereby making it possible to satisfactorily form a bulb and to reduce the diameter without relying on a hollow pile. As a solution to this problem, as a means for solving the problem, the excavating rod has an enlarged head body connected to the lower end of the excavating rod so as to be able to move up and down over a required stroke. The blade is provided so as to be expandable and contractible in a horizontal plane, and when the drilling rod is raised with respect to the expanding head main body, the expanding blade is expanded outward from the outer diameter of the drilling rod in connection with the drilling rod. It is in.

If the magnifying blade of the magnifying head body is provided with a shear pin that is sheared when the magnifying blade is expanded, the magnifying blade is expanded to a predetermined position by checking whether or not the shaping pin is cut at the end of work. It is possible to confirm whether or not the excavation has been performed.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments shown in the drawings.

FIG. 1 shows a front view of a portion of an enlarged excavating head 1 according to the present invention, and FIG. 2 shows a view taken in the direction of arrows AA in FIG. The enlarged head 1 is slidably connected to a lower end of the excavating rod 2 in a vertical direction over a required stroke L.

The enlarged head 1 has an enlarged head main body 6 having a screw blade 4 on the outer periphery of the central shaft portion 3 and a screw blade 4 on the outer periphery of the excavating rod 2, and an upper end of the enlarged head main body 6. Is inserted into a connection hole 8 having the same cross-sectional shape as the connection portion 7 at the lower end of the drilling rod 2.
Pins 9, 9 inserted into the enlarged head body 6 so as to traverse both sides inside the head are fitted into vertically extending elongated holes 10, 10 formed in the side surface of the connecting portion 7, and the enlarged head body is The range of vertical movement of 6 (a stroke of about 30 mm) is determined and is prevented.

A pair of left and right enlarged blade holders 11 are fixedly mounted on the enlarged head main body 6.
The base of the enlarged blades 12 and 12 is near the outer end of the shafts 1 and 11.
The cutting edges 12a, 12a of the expanding blades 12, 12 face in opposite directions to each other, and when the drilling rod 2 rotates forward (arrow a), the expanding blades 12, The 12 cutting edges 12a, 12a are oriented so as to be on the rear side in the rotational direction.

At the base of the enlarged blade holders 11, 11,
A cutting groove 14 is formed to extend toward a position closer to the cutting edge 12a of the magnifying blade 12 with respect to a line connecting the axis of the magnifying head main body 6 and the center of the shaft 13 of the magnifying blade 12. A slide piece 15 is slidably fitted in the inside.

Between the slide pieces 15, 15 and the central shaft portion 3 of the enlarged head body 6, left and right operation rods 17, suspended from both lower ends of the excavating rod 2 via connecting brackets 16, are provided. The lower end of 17 is inserted. The inner surfaces of the operating rods 17, 17 are arranged along the outer surface of the central shaft portion 3 of the enlarged head main body 6, and the lower outer surfaces of the operating rods 17, 17 are inclined obliquely upwardly facing inclined surfaces 18, 18 (FIG. 4). ) Are formed, and the inclined surfaces 18, 18 are
The sliding surfaces 5 and 15 are in sliding contact with each other.

The operating rods 17, 17 and the slide piece 1
When the excavating rod 2 is lowered and the enlarged head main body 6 is at a relatively elevated position, the operating rods 17, 17 do not push the slide pieces 15, 15, and the excavating rod 2 When ascending over the required stroke L with the enlarged head 1 left, the operating rods 17, 17 also ascend and slide pieces 15, 15 on the inclined surfaces 18, 18.
, And the extruded blades 12 and 12 are pushed to push the blades 12a and 1a of the enlarged blades 12 and 12 as shown in FIG.
2 a is slightly projected from the outer diameter of the drill rod 2.

At the outer ends of the enlarged blades 12, shear pins 19 are inserted so as to be kept at a reduced diameter position with respect to the enlarged head main body 6.
In the process of turning into the maximum protruding state by turning in the direction in which the a and 12a protrude, the shear pins 19, 19
It is designed to be sheared by the earth pressure on the tips of the first and the first.

In FIGS. 1, 3 (A) and 3 (B), reference numeral 20 denotes an excavating blade provided at the lower end of the enlarged head body 6, and in FIGS. 4 and 5, numeral 21 denotes a pipe for injecting a chemical such as mortar. This is for discharging a chemical solution through a spout (not shown) at the lower end of the main body 6.

Next, the operation of the above embodiment will be described.

At the start of excavation, the magnifying blades 12
(A), as shown in FIG.
The ground is excavated by the excavating blade 20 of the enlarged head 1, and excavated earth and sand is carried upward by the screw blade 5 and the screw blade 4 of the excavating rod 2 and discharged.

When a predetermined depth is reached and the lower end of the excavation hole is to be excavated, the excavating rod 2 is pulled upward with the enlarged head 1 in contact with the unexcavated bottom. Then, the operating rods 17, 17 are pulled up together with the excavating rod 2, and the inclined surfaces 18, 18 at the lower ends of the operating rods 17, 17 slide the slide pieces 15, 15 outward, and the slide pieces 15, 15 are enlarged blades. Press the side of 12,12,
The expanding blades 12 are slightly expanded (FIG. 3B, FIG. 5).
(B)).

Thus, the cutting edges 12 of the enlarged blades 12
The a and 12a are in a state where they can penetrate into the unexcavated surrounding ground and sufficiently receive the resistance of the earth and sand. Therefore, if the drill rod 2 is reversed in this state, the enlarged blade 1
Due to the resistance of the surrounding ground, Nos. 2 and 12 realize the maximum enlarged diameter as shown by the chain line in FIG. In the process of reaching this state, the shear pins 19, 19
It hits the tip of 1, 11 and is cut by shearing action.

With the expanding blades 12 and 12 expanded in this way, the drilling rod 2 is pulled upward while driving in the reverse direction, and at the same time, a chemical such as cement milk is injected through the chemical injection pipe 21. An enlarged bulb pile is formed at the excavated portion, that is, at the lower end of the pile.

When the excavated rod 2 is recovered after the formation of the enlarged bulb pile, if the excavated rod 2 is pulled up while being driven to rotate in the normal direction, the outer ends of the enlarged blades 12, 12 are pushed by the ground to reduce the diameter. You can just pull it up.

After the excavating rod 2 is pulled up to the ground, the state of the shear pins 19, 19 is checked, and if the shear pins 19, 19 are sheared, the enlarging blades 12, 12 are expanded to a predetermined opening to perform enlarging excavation. It is possible to confirm whether or not enlarged digging has been performed after construction.

[0026]

As described above, according to the present invention, at least the outer diameter of the excavating rod (when the excavating rod has a screw blade) is formed by the relative vertical movement of the excavating rod and the magnifying head connected to the lower end thereof. The outer diameter is larger than its outer diameter), so it is sure to receive the resistance of earth and sand,
Thereafter, the diameter can be enlarged to the maximum diameter without any trouble, and the expanded digging in the ground can be performed reliably.

Further, if a shear pin which is cut when the enlarging blade is expanded is provided as in claim 2, it is possible to confirm whether or not the enlarging blade has been expanded at the time of construction.

[Brief description of the drawings]

FIG. 1 is a front view of a state in which an enlarged excavating head according to the present invention is connected to a lower end of a drilling rod.

FIG. 2 is a view taken in the direction of arrows AA in FIG. 1;

FIGS. 3A and 3B are side views showing a state in which the excavating rod is lowered and FIG.

4A is a cross-sectional view of a main part of FIG. 3A, and FIG.

FIG. 5 (A) is a view in the state of FIGS. 3 (A) and 4 (A);
(B) is an explanatory view showing the state of each enlarged blade in the state of FIGS. 3 (B) and 4 (B).

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 enlarged head 2 excavating rod 4, 5 screw blade 6 enlarged head main body 7 connection portion 8 connection hole 9 pin 10 long hole 11 enlarged blade holder 12 enlarged blade 15 slide piece 17 operating rod 18 inclined surface 19 shear pin

Claims (2)

[Claims] An enlarged head body is connected to a lower end of a drilling rod so as to be vertically movable with respect to the rod over a required stroke, and an enlarged blade is provided on an outer peripheral portion of a lower portion of the enlarged head body so as to be able to expand and contract in a horizontal plane. The excavating head for excavation, wherein when the excavating rod rises with respect to the magnifying head main body, the enlarging blade is expanded outward from the outer diameter of the excavating rod in connection with the excavating rod body. 2. The magnifying head for excavation according to claim 1, wherein the magnifying blade of the magnifying head body has a shear pin that is sheared when the magnifying head is expanded.