JP2633998B2 - Casing bit with removable insert cutter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casing bit with a detachable insert cutter for excavating ground used in an all-casing method which is one of foundation pile driving methods.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 62-2285 discloses a casing bit used in an all-circumference rotary all casing method.
As disclosed in Japanese Unexamined Patent Publication No. 91-91, as shown in a vertical sectional view of FIG. 2 and an inner cutter 3 in which the inner surface of the excavated portion protrudes inward from the inner peripheral surface 1b of the casing pipe 1 in the circumferential direction.
In addition to 3, an insert cutter 4 for excavating the inner peripheral side of the casing pipe 1 is provided.

Here, one of the roles of the insert cutter 4 is to form a groove 5 on the inner peripheral surface 1b of the casing pipe 1 for facilitating discharge of cuttings excavated by the outer cutter 2 and the inner cutter 3. To do
Another function of the insert cutter 4 is to insert a hammer club into the groove 5 when a hammer club for excavating earth and sand 6 in the casing pipe 1 is inserted into the casing pipe 1. Another object of the present invention is to increase the depth of the shell and improve the discharge efficiency.

A conventional mounting structure of the insert cutter 4 is shown in FIG. 6A and its EE view.
As shown in (B), the inner peripheral surface 1b of the casing pipe 1
The holder 7 is welded (8) to form a cutter mounting portion 7a by removing the inner and outer surfaces at the center of the holder 7, and the upper fork portion 4a of the insert cutter 4 is attached to the cutter mounting portion 7a.
Are fitted and fixed by bolts 9.

[0005]

In the conventional casing bit, the groove 5 is formed by excavating earth and sand by the insert cutter 4, but the holder 7 comes into contact with the excavated earth and sand to generate friction. Therefore, in order to avoid this friction, even if the holder 7 is slightly inclined to make a relief, it is only a slight relief, and wear due to earth and sand cannot be prevented. In addition, rotational resistance is also generated due to friction between the earth and sand and the holder 7. For this reason, a tapered portion 7b is provided around the holder 7 so as to reduce the rotational resistance to some extent. In addition, the top of the holder 7 may occasionally hit the upper surface of the holder 7 with an impact.
In order to reduce the impact, a tapered portion 7c is also formed on the upper portion of the holder 7. From these points, there is a problem that the holder 7 becomes unnecessarily large.

When an earth auger is used as an excavator, the insert cutter 4 becomes an obstacle, but even if the insert cutter 4 can be removed, the holder 7 is welded (8) to the casing pipe 1 so that it can be easily obtained. There was a problem that cannot be removed.

SUMMARY OF THE INVENTION In view of the above problems, the present invention has a small excavating resistance, is compact, and does not obstruct the holder of the insert cutter even when an earth auger is used in the excavator. By shavings
Fluidization is not hindered, and the
In the middle, the shell of the digging hammer club fell,
Reducing the impact of contact with the inner surface of the cutter
It is an object of the present invention to provide a casing bit with a detachable insert cutter having a structure capable of performing the following.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides an excavating part at a lower end of a casing pipe.
Outside surface of the casing pipe is outer than the outer peripheral surface of the casing pipe.
The outer cutter protruding and the excavated part
Provided protruding inward from the inner peripheral surface of the casing pipe
The inner cutter and its excavated part
Is also provided to protrude inward.
And a casing bit formed by the inner peripheral surface of the casing pipe at the lower end of the casing pipe .
Welding the holder insert cutter as not to protrude into remote inner peripheral side, only detachably attached by bolts insert cutter to the holder, the insert cutter has its
When mounting, lower half or more of the total height inside the insert cutter.
To the slope that protrudes inward,
The top of the lower end of the carbide tip on the bottom of the
It is located on the inner peripheral side of the pipe, and its lower surface is outside the top.
It is characterized in that it is formed in a shape inclined upward toward the side .

Further, as a preferable structure in practicing the present invention, the thickness of the holder is adjusted to the thickness of the casing pipe.
And the lower end of the holder is
Tilt within the range that does not protrude inward from the inner peripheral surface of the
A structure is adopted in which the casing pipe is inclined and attached to the lower end of the casing pipe .

[0010]

In the present invention, since the insert cutter holder is welded to the lower end of the casing pipe so as not to protrude to the inner peripheral side of the casing pipe, the holder is provided with the outer cutter and the inner cutter at the lower end of the casing pipe.
As a result, the trajectory passes after the excavated trajectory, and the excavation resistance is reduced. Further, when the insert cutter is removed, the holder does not protrude toward the inner peripheral surface of the casing pipe, so that the holder does not hinder the use of the earth auger in the excavator. In addition, insert cap
The cutter is installed at its full height inside the insert cutter.
When forming more than half on the inclined surface that protrudes inward toward the bottom
In both cases, the top of the lower end of the carbide tip on the underside of the insert cutter
Is located on the inner peripheral side of the casing pipe, and
It is formed in a shape inclined upward from the top to the outside.
The insert cutter hinders the fluidization of cuttings
And facilitates the discharge of swarf.
The Maglab shell falls and falls on the inner surface of the insert cutter.
Even if it abuts , the inner surface is formed on an inclined surface,
The shell escapes inside and softens the impact of falling from above.
Can be.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 2 is a front view showing the entire casing bit according to the present invention. The casing bit 10 is fitted to a holder 11 welded to the lower end of the casing pipe 1 and is fixed to an inner cutter 13 by bolts 12.
And an outer cutter 16 fitted to a holder 14 also welded to the lower end of the casing pipe 1 and fixed by bolts 15, and a holder 1 at the lower end of the casing pipe 1.
An insert cutter 20 is fitted to the holder 18 welded between the holders 1 and 14 or between the holders 14 and 14 and fixed and attached by bolts 19.

The outer cutter 16 and the inner cutter 13 are alternately mounted at a ratio of 1: 1 or 2: 1 as shown in the figure, so that the cuttings are fluidized and the cutting resistance is reduced.
It has the effect of preventing clogging.

FIG. 3 is a sectional view taken along line FF of FIG. 2 showing the mounting structure of the outer cutter 16.
The inner and outer surfaces of the center lower portion of the holder 14 to be welded to the lower end of the outer cutter 16 are cut into a square to form a cutter mounting portion 14a, the upper fork portion 16a of the outer cutter 16 is fitted to the mounting portion 14a, and the bolt 15 is 16a and mounting part 1
4a, and is screwed into a screw hole 16c provided in the fork portion 16a to form the outer cutter 1.
6 is fixed to the holder 14. The thickness of the holder 14 is made slightly smaller than the thickness of the casing pipe 1, and the lower part is slightly inclined outward, so as to reduce frictional resistance due to contact with the ground. The lower excavation part protrudes by a width W1 slightly smaller than 1a. 16d is a carbide tip. The inner cutter 13 also employs the same mounting structure of the holder 11 (inclined to the opposite side) and the mounting structure of the cutter 13 to the holder 11 to reduce frictional resistance due to contact with the ground. Slightly smaller than the inner peripheral surface 1b
Only W2 protrudes inward. The outer cutter 16
Alternatively, the inner cutter 13 may be attached by welding.

As shown in FIG. 1 which is a sectional view taken along the line GG of FIG. 2, and FIG. 4 (A) which is a view of the holder 18 from the inside, the holder 18 of the insert cutter 20 extends from the upper center to the lower end. It has a mounting portion 18a formed by cutting the inner and outer surfaces to be thin, and the bolt insertion hole 1 is formed in the mounting portion 18a.
8b. As shown in FIG. 1, the holder 18 has a thickness slightly smaller than the thickness of the casing pipe 1, and is thinned by welding (8) by inclining the lower end of the holder 18 to be slightly inside. It is shaped. Also,
By tilting the rudder 18, the insert cutter 2
0 without increasing the thickness of the insert cover shown in FIG.
Of the inclined surface 20c inside the
The inclination angle can be easily obtained, and the insert cutter 20 can be used.
Need not be formed thicker than necessary. The lower end 18c of the holder 18 does not protrude from the inner peripheral surface 1b of the casing pipe 1.

On the other hand, as shown in the perspective view of FIG.
The insert cutter 20 is attached to the mounting portion 1 of the holder 18.
8a, a fork portion 20a to be fitted to the fork portion 8a is formed at an upper portion, and a reinforcing portion 20b that is integral with the fork portion 20a and has a wider left and right width than the fork portion 20a is formed inside the fork portion 20a. The inner side is formed on an inclined surface 20c that protrudes inward toward the lower side, and the outer side surface 20d is formed on the holder 1.
8 as the contact surface. In addition, a carbide tip 20f projecting downward in a mountain shape is welded to a portion of the insert cutter 20 which is a front surface in the rotation direction during excavation. The lower part of the fork part 20a has a jaw part 20 to be brought into contact with the lower surface 18c of the holder 18.
g. A bolt insertion / head receiving hole 20h is formed in an outer portion of the fork portion 20a, and a screw hole 20i is formed in an inner portion of the fork portion 20 as shown in FIG. Also, as shown in FIG. 1, a portion inside the top 20j of the carbide tip 20f forms a steeply inclined surface 20p,
Outside the apex 20j, an inclined surface 20q having a large difference in height is formed over a wider area that is gentler than the inclined surface 20p.

The insert cutter 20 is shown in FIG. 1 and FIGS. 5 (A) and 5 (B), which are views as viewed from arrows A and B, respectively.
As shown in the figure, the fork 20a is fitted to the mounting portion 18a of the holder 18, the jaw 20g of the insert cutter 20 is brought into contact with the lower surface 18c of the holder 18, and the bolt 19 is inserted into the hole 18b of the fork 20a and the mounting portion 18a. The insert cutter 20 is detachably attached to the holder 18 by being inserted and screwed into a screw hole 20i provided inside the fork portion 20a. Thus, the insert cutter 2
By contacting the lower jaw 20g with the lower surface 18c of the holder 18, the load applied to the carbide tip 20f during excavation is supported to reduce the size of the holder 18. In addition, at the time of mounting, the outer surface 20d of the reinforcing portion 20b of the insert cutter 20 comes into contact with the inner surface of the holder 18 and receives a force acting on the insert cutter 20 from inside. Also, in this mounting state, by reducing the thickness of the mounting portion 18a from the gap between the fork portions 20a, the outer portion of the fork portion 20a is bent by tightening the bolt 19, and a spring effect is generated to prevent the bolt 19 from loosening. doing.

At the time of excavation work, the casing bit 10 is rotated by a carbide tip in a direction in which the ground can be excavated, and a vertical force is applied from above. Thereby, the outer cutter 16, the inner cutter 13, and the insert cutter 20 bite into the ground, and scrape the ground little by little. The shaved swarf flows backward and is fluidized by being pushed laterally by a rear cutter. At this time, the top 20j of the lower surface of the insert cutter 20 is located inside the inner peripheral surface 1b of the casing pipe 1 and forms the inclined surface 20q over a wide range from the top 20j to the outside. The cutter 20 does not hinder, the excavation of the excavation is easy, and an increase in excavation resistance due to the insert cutter 20 can be prevented.

Further, since a groove is formed in the inner peripheral surface of the casing pipe 1 by the insert cutter 20, excavation is discharged upward from a place where the flow resistance is small. By discharging the cuttings, the resistance object is eliminated, and the casing bit 10 can be further pushed down.

The upper portion of the insert cutter 20 is formed on an inclined surface 20c (preferably, the inclined surface 20c is formed to be at least about half of the entire length inside the insert cutter 20). Even if the shell of the hammer club that excavates the abutment comes into contact with the inner surface of the insert cutter 20, the shell escapes inward, softens the impact of falling from above, and can avoid damage. Also,
By forming the tapered shape having the inclined surface 20c, the frictional resistance is reduced and the loss of the excavating force can be reduced.

When an earth auger is used instead of a hammer grave as an excavator, the insert cutter 20 is removed. However, if the bolt 19 is loosened, it can be easily removed. Further, since the holder 18 does not protrude inward, the holder 18 does not come into contact with the earth auger, so that damage can be prevented. Although the holder 18 does not protrude inside the casing pipe 1, the place where the insert cutter 20 is attached is protruded inside the casing pipe 1 in order to prevent the place where the insert cutter 20 is attached from being washed or damaged by earth and sand. A cap manufactured in a range that does not exist may be attached instead of the insert cutter 20.

[0021]

According to the first aspect of the present invention, since the insert cutter is bolted to the holder, the insert cutter can be easily attached and detached, and the holder protrudes from the inner peripheral surface of the casing pipe. Since it was welded to the casing pipe so that it does not, when excavating by removing the insert cutter, such as when drilling with a ground auger, the holder does not interfere,
It is not damaged by auger contact. Further, when excavating with the insert cutter removed, the holder can be reduced in size because it does not increase the excavating resistance and does not need to have rigidity to withstand the excavating resistance.

In addition , at least half of the total height inside the insert cutter is formed on an inclined surface with the lower part projecting inward, and the lower surface of the insert cutter is positioned such that the lower end top of the carbide tip is located on the inner peripheral side of the casing pipe; Since it is formed in a shape inclined upward from the top to the outside, the fluidization of the cuttings is not hindered by the insert cutter, and the discharge of the cuttings is facilitated. In addition, since at least half of the total height inside the insert cutter is formed on an inclined surface with the lower part projecting inward, even if the shell of the Hamamaglab that excavates inside the casing pipe abuts against the inner surface of the insert cutter, the inner surface is formed.
Since the shell is formed on the inclined surface, the shell escapes to the inside, so that a drop impact from above can be relieved and damage to the insert cutter can be avoided . In addition,
When installing an insert cutter on the inner wall of a cutting pipe
Requires a predetermined mounting length, and inserts
Insert cutter to extend the
In the case of the present invention, the casing pipe is enlarged.
Provide a holder at the lower end and insert a cutter into the holder.
Since it is mounted, the insert cutter can be downsized. Claim
According to Item 2, the thickness of the holder is adjusted to the thickness of the casing pipe.
Slightly narrower, so that the lower end of the holder is slightly inside
Since the holder is mounted at an angle, the holder can be made thinner. Ma
Also, by inclining the holder, insert cutter
Without increasing the thickness of the insert cutter.
Easily obtain the desired inclination angle with respect to the vertical line of the inclined surface
And make the insert cutter thicker than necessary
No need.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view taken along line GG of FIG. 2 showing one embodiment of a casing bit with a removable insert cutter according to the present invention.

FIG. 2 is a front view showing one embodiment of a casing bit according to the present invention.

FIG. 3 is an enlarged sectional view taken on line FF of FIG. 2;

FIG. 4A is a front view of a holder according to the present embodiment, and FIG. 4B is a perspective view of an insert cutter.

5 (A) and 5 (B) are views as viewed from an arrow A in FIG. 1 and FIG.
It is an arrow view.

FIG. 6A is a longitudinal sectional view showing a conventional cutter mounting portion, and FIG. 6B is a view taken along the line EE of FIG. 6A.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Casing pipe 1a Outer peripheral surface 1b Inner peripheral surface 10 Casing bit 11, 14, 18 Holder 12, 15, 19 Bolt 13 Inner cutter 16 Outer cutter 20 Insert cutter 20a Hawk part 20g Jaw part 20c, 20p, 20q Inclined surface 20f Carbide tip

Claims (2)

(57) [Claims] An excavating part is provided at a lower end of a casing pipe.
Outside surface of the casing pipe is outer than the outer peripheral surface of the casing pipe.
The outer cutter protruding and the excavated part
Provided protruding inward from the inner peripheral surface of the casing pipe
The inner cutter and its excavated part
Is also provided to protrude inward.
In the casing bit constituted by the jitter, the lower end of the casing pipe, of the casing pipe
Welding the holder insert cutter as not to protrude on the inner peripheral side of the peripheral surface, only detachably attached by bolts insert cutter to the holder, the insert cutter insert cut at the time of mounting
Tilt more than half of the total height inside the
Formed on a slope, and carbide on the lower surface of the insert cutter
The top of the lower end of the tip is located inside the casing pipe
And tilt the lower surface upward from the top to the outside.
A casing bit with a detachable insert cutter, which is formed in an inclined shape . 2. The method according to claim 1, wherein the thickness of the holder is
The holder is formed to be thinner than the wall thickness of the casing pipe, and the lower end of the holder has an inner peripheral surface of the casing pipe.
The casing is inclined so that it does not protrude inward.
A casing bit with a detachable insert cutter attached to a lower end of a pipe .