JPH08312293A - Shield excavator - Google Patents

Abstract

PURPOSE: To retract a front bit when it is not necessary so as to prevent damage such as wear by enabling the tip end of the front bit to longitudinally move back and forth past the tip end of another cutter bit. CONSTITUTION: In a shield excavator 10, some of plural cutter bits are used as front bits 30..., which are made to break natural ground prior to other cutter bits. The front bits 30 are secured to a mounting portion whose area is larger than the width of each front bit 30, and the mounting portion is slid by a jack or the like against the inside surface of a guide portion provided at a cutter head 12, and is driven so as to move back and forth in its longitudinal direction. Therefore, the tip end of the front bit 30 can longitudinally move back and forth past the end of another cutter bit. Therefore, the front bit 30 is retracted when not in use so as to prevent damage such as wear.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield excavator equipped with a preceding bit and excavating while performing landslide.

[0002]

2. Description of the Related Art Conventionally, as one of the shield construction methods, there is known a construction method in which a cutting face is mechanically and continuously excavated by a cutter head provided in a shield machine. There is. Specifically, the cutting face is excavated by a cutter bit attached to the cutter head.

It is also known to attach a preceding bit to a cutter head as one of the cutter bits. The preceding bit is intended to cut ground before the other cutter bits to facilitate excavation and reduce wear of the other cutter bits.

By the way, the soil quality of the ground excavated by the shield machine is not uniform and generally changes as the excavation proceeds. The soil layer structure includes, for example, a consolidated silt layer and a gravel layer.

Since the consolidated silt layer is a layer in which clay is consolidated by consolidation and dehydration, the preceding bit is effective when excavating the ground of such a layer. .

On the other hand, the gravel layer is a layer made of stone fragments larger than sand, and is not consolidated like the consolidated silt layer. Therefore, when a shield machine advances through such a layer, it is relatively easy to excavate a face, and another problem arises only how to crush and incorporate gravel having a large diameter into small pieces. . Therefore, in this case, the preceding bit is unnecessary.

However, although there is no need, according to the conventional shield machine, since the preceding bit is always attached, there is a problem that the wear is accelerated. Further, in order to avoid this problem, the leading bit must be attached and detached every time the soil layer changes, which is not troublesome.

Japanese Unexamined Patent Publication (Kokai) No. 6-272487 discloses a technique of providing a retractable second cutter bit in addition to the fixed first cutter bit. The bit is extruded when the first cutter bit is worn to enable continuous long-distance excavation. Therefore, the second cutter bit is provided as a spare when the first cutter bit is worn, is not used as a preceding bit as in the present invention, and prevents wear itself. It is not a means to

The present invention has been made in view of the above problems, and an object thereof is to provide a shield machine capable of preventing damage to a preceding bit.

[0010]

In order to achieve the above object, the invention according to claim 1 is a shield machine,
A part of the multiple cutter bits is used as a leading bit to perform ground collapse ahead of other cutter bits, and the leading bit is driven so that its tip moves forward and backward relative to the tips of other cutter bits. It is characterized by being done.

According to a second aspect of the present invention, in the shield machine according to the first aspect, the leading bit is fixed to a mounting portion having an area larger than its width, and the mounting portion is moved forward and backward by a driving means. The leading bit is driven by doing so, and the mounting portion slides on the inner surface of the hole provided in the cutter head.

According to a third aspect of the present invention, in the shield machine according to the second aspect, a plurality of the preceding bits are fixed to the mounting portion, and the plurality of preceding bits are driven forward and backward simultaneously. And

[0013]

According to the present invention, the leading bit projects or retracts with respect to the other cutter bits.

Therefore, when the leading bit is required, the leading bit is projected to break the ground, and when the leading bit is not required, the leading bit can be retracted to prevent damage such as abrasion.

According to the second aspect of the present invention, the preceding bit is attached to the attaching portion which is a relatively large member, and the attaching portion moves back and forth. Therefore, since the driven member is a large member, the excavated soil is less likely to be clogged when sliding on the inner surface of the hole. In this respect, when only the leading bit is projected and slid from the hole or slit, the leading bit is a relatively small member and cannot be driven because the soil is clogged, so the present invention avoids this. it can.

Further, according to the third aspect of the invention, since the plurality of leading bits are fixed to the mounting portion, it is possible to drive the plurality of leading bits by one driving means.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing the entire shield machine according to the embodiment. Referring to FIG. 1, a shield machine 10 mechanically and continuously excavates a face using a cutter head 12 provided on a front surface of the shield jack 1.
At 4, a segment (not shown) receives a reaction force to dig forward. In addition, the segment is the elector device 1
Assembled by 6.

The cutter head 12 is supported by a swivel base bearing 20 and is rotated by a motor 22. The driving power for advancing and retracting the preceding bit is supplied by the rotary joint 18. When the cutter head 12 rotates, various cutter bits provided on the cutter head 12 excavate the natural ground. FIG. 2 is a front view of the cutter head 12. As shown in FIG. 2, the cutter bit includes a center bit 12a and a tooth bit 12 as a cutter bit.
b, a roller bit 12c, an overcut roller bit 12d, and a preceding bit 30 are provided. Here, the preceding bit 30 has a characteristic configuration of the present embodiment, but as the other cutter bits other than this, known ones are used, and a detailed description thereof will be omitted.

Further, the shield machine 10 employs a muddy water type shield construction method, and the cutter chamber 2
A mud sending pipe 26 for sending mud water and a mud discharging pipe 28 for sending discharged mud water containing excavated earth and sand are provided.

Next, the preceding bit 30 will be described.
The feature of the preceding bit 30 is, in short, that it is driven in the front-rear direction. In FIG. 1, the retracted state is shown by a solid line, and the protruding state is shown by a broken line. Here, the retracted state means another cutter bit (center bit 1
2a, teeth bit 12b, roller bit 12c,
The leading edge of the leading bit 30 is retracted rearward from the leading edge of the overcut roller bit 12d), and the protruding state is the leading edge of the leading bit protruding more than the leading edge of another cutter bit.

3A and 3B are views for explaining the driving means of the preceding bit 30, specifically, FIG. 3A is a cross-sectional view seen from the lateral direction, and FIG. 3B is seen from the vertical direction. FIG.

As shown in these figures, the leading bit 30
Is fixed to the mounting portion 32, and the mounting portion 32 is moved back and forth by the jack 34. Specifically, the mounting portion 32 has a columnar box shape including the front plate 32a, the side plate 32b, and the rear plate 32c (see FIG. 2), and the reinforcing plate 32d is mounted on the rear plate 32c. Then, the two leading bits 30 are attached to one front plate 32a, the jack 34 is attached to the rear plate 32c and the reinforcing plate 32d, and the drive rod 34a of the jack 34 projects rearward from the rear plate 32c and the reinforcing plate 32d. Shield machine 1
The drive rod 34a is attached to the rotary plate 36 of 0 (see FIG. 1).

With such a structure, if the jack 34 is driven and the drive rod 34a is projected, the leading bit 3 is pushed as the mounting portion 32 is pushed forward.
If 0 projects forward and retracts the drive rod 34a,
As the mounting portion 32 retracts, the leading bit 30 also retracts. When the preceding bit 30 is needed, it can be projected to collapse the ground, and when the preceding bit 30 is not needed, it can be retracted to prevent damage such as abrasion. The case where the preceding bit 30 is necessary and the case where the preceding bit 30 is not necessary are as described in the section of the problem to be solved by the conventional technology and the invention.

Further, in the present embodiment, since the two leading bits 30 are attached to the one mounting portion 32, the two leading bits 30 can be driven by one driving means.

Further, the mounting portion 32 slides in the guide portion 38. The guide portion 38 is formed by forming a cylindrical outer wall on the rotary plate 36 and forming a cylindrical hole inside. The guide portion 38 is provided with a packing 38a, and the mounting portion 32 is provided with the packing 38a.
The guide portion 38 is slid so that earth and sand do not enter inside due to a. Here, the mounting portion 32 is a member that is larger than the leading bit 30, as is clear from the fact that the two leading bits 30 are mounted. Therefore, compared with the case where a single preceding bit 30 is driven, the sliding portion is less likely to be clogged with earth and sand.

Next, FIG. 4 is a diagram for explaining the action of cutting the ground by the preceding bit. In this embodiment, two leading bits 30 are attached to each of the four mounting portions 32, so that a total of eight leading bits are provided. And
When the cutter head 12 is rotated with the preceding bits 30 projected, eight scoring 40 can be performed as shown in FIG.

As a premise for this, it is necessary to arrange the preceding bits 30 so that the distance from the center of rotation of the cutter head 12 is different.

[0028]

As described above, according to the present invention,
When the leading bit is needed, the leading bit can be projected to collapse the ground, while when the leading bit is not needed, the leading bit can be retracted, so that damage such as wear can be prevented in this case. it can.

[0029]

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an entire shield machine according to an embodiment.

FIG. 2 is a front view of a cutter head.

3A and 3B are views for explaining a driving unit of a preceding bit, FIG. 3A is a cross-sectional view seen from the lateral direction, and FIG. 3B is a cross-sectional view seen from the vertical direction.

FIG. 4 is a diagram for explaining the action of cutting off the ground with a preceding bit.

[Explanation of symbols]

 10 shield machine 30 leading bit 32 mounting portion 34 jack (driving means) 38 guide portion (hole portion)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasutomo Katori 1-7-1, Kyobashi, Chuo-ku, Tokyo Toda Construction Co., Ltd.

Claims (3)

[Claims] 1. In a shield machine, a part of a plurality of cutter bits is used as a leading bit to perform ground breaking prior to another cutter bit, and the leading bit has a tip end of another cutter bit. A shield excavator characterized by being driven to move forward and backward from the tip. 2. The shield machine according to claim 1, wherein the leading bit is fixed to a mounting portion having an area larger than a width of the leading bit, and the mounting portion is moved forward and backward by a driving means. The shield machine according to claim 1, wherein the attachment portion slides on an inner surface of a hole provided in the cutter head. 3. The shield machine according to claim 2, wherein a plurality of the preceding bits are fixed to the mounting portion,
A shield machine, which drives the plurality of preceding bits forward and backward simultaneously.