JP3916747B2 - Ground improvement agitation head - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a ground improvement stirring head for improving excavated ground.
[0002]
[Prior art]
The upper and lower stirrer blades are attached to the lower end of a rod that is connected to the output shaft of a drive unit that is supported so as to be able to move up and down along the tower of the work machine. Conventionally, a ground improvement stirring head that stirs and kneads an agent (chemical solution) to strengthen the ground is generally used.
[0003]
[Problems to be solved by the invention]
Therefore, when the conventional stirring head is used in the ground containing a lot of viscous soil, as shown in FIG. 4, the earth and sand c adhere to the stirring blades b and b of the excavating rod a, and this attached earth and sand c gradually grows. As a result, the space between the stirring blades b and b is filled up, and finally becomes a dumpling, so that there is a problem that the mixing and stirring function of the excavated earth and sand is lost.
[0004]
[Means for Solving the Problems]
Even if excavated earth and sand adhere to the periphery of the rod between the stirrer blades of the plurality of stages, the present invention eliminates this in a timely manner in the ground and prevents the adhering earth and sand from growing in a dump shape between the agitator blades. An object of the present invention is to provide a ground improvement stirring head capable of continuously maintaining a stirring function.
[0005]
As a means for solving the above-mentioned problems, the present invention provides a ground improvement stirring head in which a plurality of stirrer blades are attached to the lower end of a rod that is coupled to a drive unit and is freely suspended. A mud removal plate is attached to the outer periphery of the rod between the blades so as to be capable of swiveling, and an operating claw is provided at the outer end of the stirring blade that can be expanded by receiving the resistance of earth and sand due to the reverse rotation of the rod. An exclusion plate is connected by an interlocking mechanism, and when the operating claw is expanded, the mud exclusion plate is pivoted in a direction away from the rod via the interlocking mechanism.
[0006]
Since the interlocking mechanism can be configured with a configuration in which a position eccentric with respect to the pivot of the operation claw and a position separated from the pivot of the mud removal plate are connected by a link, a reliable operation can be achieved with a simple configuration. This is a preferred form.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below with reference to embodiments shown in the drawings.
FIG. 1 shows a front view of an embodiment of the agitation head according to the present invention, and FIG. 2 shows a cross-sectional view taken along the line AA in FIG. ing.
[0008]
The upper end of the rod 1 is connected to a drive unit (not shown), and when excavated, the rod 1 is rotated in the direction of arrow (forward rotation) to excavate a pit. Inside, a ground improver (cement milk) or the like is provided. A chemical solution supply path 3 for supplying the chemical solution is provided, and the chemical solution supply path 3 is opened at the front end of the central portion of the excavation head 2 so that the chemical solution is discharged into the excavation soil.
[0009]
On the rod 1 above the excavation head 2, a plurality of stirrer blades 4A, 4B,... These agitating blades 4A and 4B are blade-shaped with a flat rectangular shape as seen in FIG. 2, and the length thereof is substantially equal to the diameter of the excavation hole (excavation diameter D) by the excavation head 2. Has been.
[0010]
Among the stirring blades 4A, 4B,..., A pair of mud removal plates 5 and 5 are provided on the outer peripheral surface of the rod 1 between the same-phase stirring blades (indicated by reference numerals 4A and 4A).
[0011]
The mud removal plates 5 and 5 are formed on a circular arc surface whose side in contact with the outer peripheral surface of the rod 1 is equal to the radius of the outer periphery of the rod 1, and one end thereof corresponds to the stirring blades 4A and 4A of the rod 1 Are supported by shafts 7 and 7 on bearings 6 and 6 projecting on both sides of the position where the mud removal plates 5 and 5 can pivot in the direction away from the rod 1. Installed on.
[0012]
On the other hand, at the tips of the stirring blades 4A and 4A, the bases of the operating claws 8 and 8 are arranged in a horizontal plane in the direction in which the shafts 9 and 9 have the tips 8a and 8a on the rear side with respect to the rotational direction when the rod 1 rotates forward. It is attached so that it can rotate freely. The operating claws 8, 8 take a position (referred to as a retracted position) that is retracted to the inside of the excavation diameter D of the excavation hole by the excavation head 2 when the actuating claws 8 and 8 are rotated at right angles to the longitudinal direction of the agitating blades 4A, 4A. The blades 4A, 4A are formed so as to project outward from the excavation diameter D (referred to as projecting positions) when the blades 4A and 4A are rotated in such a posture, and thus actuate when the rod 1 is reversed. The tips 8a and 8a of the claws 8 and 8 can contact the surrounding ground and rotate to the protruding state by the resistance.
[0013]
The mud removal plates 5 and 5 and the operating claws 8 and 8 are connected via interlocking mechanisms 10 and 10 at the positions of the upper and lower stirring blades 4A and 4A, and the operating claws 8 and 8 receive resistance to the ground. The mud removal plates 5 and 5 are swung in a direction away from the outer peripheral surface of the rod 1 when rotated in the protruding direction.
[0014]
In the illustrated example, when the operating claws 8, 8 are placed in the retracted position (the position shown in FIG. 2), the bearings 11, 11 projecting at the position on the rod 1 side, and the mud removal plates 5, 5 The links 13 and 13 are rotatably connected to the bearings 12 and 12 protruding from the outer surfaces of the free ends 5a and 5a by pins 14 and 15, and the operating claws 8 and 8 are in the protruding position (the position shown in FIG. 3). ), The mud removal plates 5 and 5 are configured to turn in a direction away from the rod 1 with the shafts 7 and 7 as fulcrums.
[0015]
In the illustrated embodiment, since the stirring blade 4B having a phase difference of 90 ° exists between the stirring blades 4A and 4A, the intermediate stirring is performed from the free ends 5a and 5a of the mud removal plates 5 and 5. A cutout 5b (shown in FIG. 1) for avoiding the wing 4B is formed.
[0016]
Next, the work procedure will be described.
[0017]
The rod 1 is driven to rotate forward by a drive unit (not shown), and the ground is drilled by the excavation head 2 at the lower end thereof. At this time, the chemical solution is supplied through the chemical solution supply path 3 in the rod 1, the chemical solution is discharged from the lower end of the excavation head 2, and mixing and agitation of the excavated sediment and the chemical solution is performed by the stirring blades 4 </ b> A, 4 </ b> B.
[0018]
When the ground is viscous soil, it grows gradually by adhering to a member (stirring blade) protruding outward due to the viscosity of the excavated earth and sand, and finally includes a dumpling shape including the stirring blades 4A, 4B. In order to prevent this situation from occurring, the excavation operation is interrupted in a timely manner and the rod 1 is driven in reverse rotation. Do.
[0019]
When the rod 1 is reversed, the operating claws 8, 8 at the tips of the stirring blades 4a, 4a rotate in the direction of arrow B in FIG. 3 due to the resistance when the tips 8a, 8a hit the surrounding ground. The links 13 and 13 are pulled by the movement, and the mud removal plates 5 and 5 are forcibly swiveled in the direction away from the rod 1 with the shafts 7 and 7 as fulcrums, and the earth and sand surrounding the rod 1 are moved by the movement. The earth and sand that has been made into a dumpling shape as a result of shearing is divided and subdivided, and the stirring blades 4A, 4A, and 4B are exposed again, and the original stirring and mixing function is restored. Thus, when excavating the viscous ground, the ground can be improved satisfactorily by performing the above operation intermittently several times.
[0020]
If the rod 1 is returned to the normal rotation again and the excavation work is resumed, the working claws 8 and 8 are forcibly returned to the retreated position with the tips 8a and 8a coming into contact with the surrounding ground excavated by the excavation head 2. The mud removal plates 5 and 5 are returned to the outer periphery of the rod 1 through the links 13 and 13 as shown in FIG.
[0021]
The mud removal plates 5 and 5 are not limited to plate-like ones but may be comb-like ones.
[0022]
【The invention's effect】
As described above, according to the present invention, when the ground of the viscous geology is improved, the earth and sand adhering to and around the stirring blade can be eliminated by simply reversing the rod in a timely manner. The stirring and mixing action can be performed satisfactorily, and the ground improvement accuracy can be remarkably increased.
[Brief description of the drawings]
FIG. 1 is a front view of a main part showing an embodiment of a stirring head according to the present invention.
FIG. 2 is a cross-sectional view taken along the line AA in FIG.
FIG. 3 is an operation explanatory diagram when the rod is reversed from the state of FIG. 2;
FIG. 4 is an explanatory diagram showing a conventional defect.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Rod 2 Excavation head 3 Chemical solution supply path 4A, 4B Agitation blade 5 Mud removal plate 8 Actuation claw 10 Interlocking mechanism 13 Link

Claims (2)

In a ground improvement stirring head having a plurality of stirrer blades attached to the lower end of a rod that is coupled to a drive unit and is rotatably suspended, a mud removal plate is disposed on the outer periphery of the rod between the stirrer blades provided in the plurality of steps. It is mounted so that it can swivel, and an operating claw that can be expanded by receiving the resistance of earth and sand due to the reverse rotation of the rod is provided at the outer end of the stirring blade, and this operating claw and the mud removal plate are connected by an interlocking mechanism. The ground improvement agitation head characterized in that when the operating claw is expanded, the mud removal plate pivots in a direction away from the rod via the interlocking mechanism. 2. The ground improvement stirring head according to claim 1, wherein the interlocking mechanism is configured such that a position eccentric with respect to a pivot of the operating claw and a position separated from the pivot of the mud removal plate are connected by a link.

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