JP3497696B2 - Split unit structure of pipe propulsion tip device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a divided portion of a pipe propulsion tip device for laying a cable laying pipe, a water and sewer pipe, a gas pipe, etc. in the soil by non-excavation in a compaction-free and soil-free system. Is.

[0002]

2. Description of the Related Art A procedure for laying a pipe in a compaction-free soil-free system by a small diameter pipe propulsion method will be described with reference to FIGS. This is a construction method of digging from the starting shaft A toward the reaching shaft B by the tip device C and laying the pipe E by pushing it while adding it. The tip device C can be divided into a front structure C2 and a rear structure C3 at a joint surface C4, has a head C1 for digging at the tip of the front structure C2, and uses this head C1 with a built-in tip jack. Can be extended / retracted.

(1) A starting push device D having a pushing push jack D1 and a tip device C for propelling a pipe are arranged in a starting shaft A (FIG. 7A). At this time, the rear end of the rear structure C3 is arranged so that it can be pressed by the original push jack D1.

(2) The original push jack D1 is extended to press the tip device C into the reaching shaft side (FIG. 7B). (3) Pull back the jack D1 and secure a space corresponding to the length of the pipe E between the rear end of the tip device C and the pressing surface of the original push jack D1 (FIG. 7C). (4) Insert the tube E into this space (Fig. 7D).

(5) The head C1 of the tip device is extended by a tip jack to dig into the soil (FIG. 8A). (6) The original push jack D1 is extended, and the tip device C and the pipe E are pushed toward the reaching shaft by the length of the excavation (Fig. 8).
B). (7) In this way, pipe E is laid while adding pipe E by repeating the steps of "digging → pushing pipe E and tip device C → retracting original push jack D1 → arrangement of next pipe → digging." . The head C1 can be slightly swung with respect to the front structure C2 (FIG. 8C), and the digging is performed while correcting the deviation in the propulsion direction (FIG. 8D).

(8) When the tip device C reaches the reaching shaft B (FIG. 9A), the front structure C2 and the rear structure C3 are separated at the joint surface C4, and the front structure C2 is reached to the reaching shaft B. (Fig. 9B). (9) The rear structure C3 is pushed by the original push jack D1 until it is completely exposed in the reaching shaft (Fig. 9C). (10) Then, the rear structure C3 is removed (FIG. 9D).

When a pipe is laid by the above-mentioned compaction-free soil-removal method, the resistance to press-fitting into the soil is very large because the soil is not excavated and discharged when the pipe is propelled. In particular, a large bending moment acts on the device itself when controlling the direction of the tip device. Two structures shown in FIG. 10 and FIG. 11 are known as the divided part structure of the tip device in consideration of such bending moment.

The structure shown in FIG. 10 is a divided part structure in which a front structure C2 and a rear structure C3 are joined by using a bolt G and a nut H. Plural bolts G are passed through the flanges at the joint ends of the front structure C2 and the rear structure C3, and the nuts H are tightened to bond the two structures C2 and C3.

On the other hand, the structure of FIG. 11 is a divided portion structure in which the front structure C2 and the rear structure C3 are joined by using a cap nut J. A male screw N is formed at the joint end of the front structure C2, and a flange O is formed at the joint end of the rear structure. Then, both structures are joined by a cap nut J having one end engaged with the flange O and the other end having a female screw M screwed into the male screw N.

[0010]

However, the above-mentioned division structure has the following problems. The split structure of FIG. 10 is not sufficient to withstand large bending moments. When a bending load is applied to the lower part of the front structure shown in FIG. 10A, a tensile force acts on the upper part of the joint surface and a compressive force acts on the lower part. At this time, the tensile force applied to the joint surface is not advantageous in terms of strength because it must be supported only by the bolts attached to the upper half of the pipe (FIG. 10B) instead of all the bolts.

Although the divided portion structure of FIG. 11 is advantageous in terms of strength against bending moment, it requires a large working space when dividing and removing the tip device. This structure is advantageous in terms of strength because the tensile force applied to the upper part of the joint surface is supported by the upper half of the cross section of the cap nut when a bending load is applied below the front structure of FIG. However, as shown in FIG. 12, when the tip device is divided, it is necessary to rotate the cap nut to release the screw engagement with the front structure. At that time, since the front structure is moved in a direction away from the rear structure, an extra divided work space is required by a length corresponding to the screwing length. Therefore, if the inside of the reaching shaft is narrow, it may be difficult or impossible to divide the tip device.

[0012] Therefore, a main object of the present invention is to provide a dividing structure of a tip device having a sufficient bending resistance and capable of facilitating dividing work even in a narrow shaft.

[0013]

The present invention achieves the above object by providing a flange portion at the joint end portion of the front / rear structure and attaching a split ring to the flange portion to join the flange portion. That is, the split ring has a groove that fits into the flange portion and is configured to be separable into a plurality of divided pieces, and each divided piece has a coupling mechanism with an adjacent divided piece. When the tip device is divided, the divided pieces of the split ring may be disconnected and the divided pieces may be removed in the outer peripheral direction.

Here, the shapes of the flanges in both the front and rear structures are not particularly limited. However, it is preferable that the vertical cross-sectional shape of the flange portion when the two structures are joined is trapezoidal. When such a flange is tightened from the outer circumference with a split ring, the structures are pressed against each other in the direction of joining to each other, so that higher bending resistance can be obtained.

The groove of the split ring has a shape corresponding to the above flange. In addition, the number of divided pieces forming the split ring is not particularly limited. As a connecting mechanism of each divided piece,
A rotary shaft attached to one end of each divided piece, a rotatable bolt screwed to the rotary shaft, and a bolt head of an adjacent divided piece formed at the other end of each divided piece. The one with a notch is mentioned.

When a washer is used under the neck of the above bolt,
The washer preferably has a non-uniform thickness and a wedge-shaped cross section. Further, it is desirable that the engagement surface of the notch with which the washer under the bolt neck abuts is inclined at an acute angle with respect to the bottom surface of the notch. With these configurations, when the split ring is attached to the flange and the bolt is tightened, the operation of rotating the bolt as the diameter of the split ring decreases can be made smooth.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIG.
4 to 4. FIG. 1 (A) is a plan view showing a joined state of the split portion structure of the present invention, FIG. 1 (B) is a vertical sectional view thereof, and FIG. 2 is a lateral sectional view taken along the line XX of FIG. 1B. 3 (A) is a plan view showing a separated state of the dividing portion structure of the present invention, FIG. 3 (B) is a longitudinal sectional view thereof, and FIG. 4 is a state in which the split ring is removed.
FIG. 7 is a lateral cross-sectional view taken along line YY of FIG.

The split portion structure of the present invention has a structure in which the front structure C2 and the rear structure C3 of the tip device are butted against each other, and the butted portions are joined together by tightening the split ring 1 from the outer periphery.

The joint ends of the front structure C2 and the rear structure C3 have substantially the same structure, and a flange 2 and a groove 3 are formed (FIGS. 1A and 3). The flange 2 is an annular projection that is continuous with the joint surface C4 and projects to the outer periphery, and the groove 3 is an annular recess that is continuous with the flange 1. In this example, the outer diameter of the groove 3 is the smallest, the outer diameter of the flange 2 is the largest, and the outer diameter of the front / rear structure other than the joint ends is the largest. A circular groove is formed on the joint surface C4 of the front structure, and an O-ring 4 is inserted in this groove to prevent water from entering from the divided portion.

Here, the vertical cross-sectional shape of the flange 2 when the two structures C2 and C3 are joined together is a trapezoid (FIG. 1B). That is, the joined flange 2 has a wedge shape having an angle θ1, and has a configuration in which the width is narrower on the outer peripheral side and wider on the inner peripheral side. As will be described later, this wedge shape makes it possible to form a divided portion having a higher bending resistance.

A split ring 1 is mounted on the joint ends of the two structures C2 and C3 (FIGS. 1B, 2 and 4). The split ring 1 is formed into an annular shape by connecting three arc-shaped divided pieces, and a groove 5 (FIG. 1B) into which the flange 2 is fitted is formed on the inner circumference, and both ends are adjacent to each other. It has a mechanism for connecting with the split pieces.

A rotatable hexagon socket head cap bolt 6 is used for this connecting mechanism. Two grooves 7 are formed along the circumferential direction on the outer peripheral surface on one end side of each divided piece, and a rotary shaft 8 is bridged in the grooves. A bolt 6 is screwed onto the rotary shaft 8 in the orthogonal direction. On the other hand, the other end side of each divided piece has a notch 9 with which the head of the bolt 6 is engaged. The notch 9 has an L-shaped cross section formed by leaving the other end surface of the divided piece, and is formed on both sides of each divided piece so as to face each other and form an engagement surface 9A with the bolt head. The engaging surface 9A is provided with an inclination of an angle θ2 (Fig. 2). That is, the inner peripheral edge of the engagement surface 9A is inclined near the other end surface 1A of the divided piece and the outer peripheral edge is inclined so as to be separated from the other end surface 1A of the divided piece. And the engagement surface
A groove 10 into which the shaft portion of the bolt 6 is fitted is provided between 9A and the other end surface 1A of the split piece (FIG. 1B).

Further, in this example, a square washer is provided under the neck of the bolt 6.
I put on 11. The square washer 15 is not uniform in thickness and has a wedge-shaped cross-sectional shape (FIGS. 2 and 4). The angle formed by the wedge-shaped cross section corresponds to the inclination angle θ2 of the engaging surface 9A. When the split ring 1 is attached to the flange 2 and the bolt 6 is tightened by the wedge-shaped square washer 11 and the inclination of the engagement surface 9A, the bolt head is rotated in the inner circumferential direction to ensure the tightening. To

Although not shown, the front structure C2 has a swingable head at the tip and a tip jack inside, and the head is extended and retracted by this jack to dig ahead.

The procedure and operation for joining / dividing the above-mentioned divided portions are as follows. (1) When joining, the joining ends of the front structure C2 and the rear structure C3 are butted, and the groove 5 of each divided piece is fitted into this flange 2 (FIGS. 1 and 2). (2) Rotate each bolt 6 to engage the notch 9 of the adjacent divided piece. At this time, the square washer 11 has a larger thickness on the engaging surface.
The inner side of 9A is aligned with the smaller side to the outer side of engagement surface 9A.

(3) The bolts 6 are screwed into the rotary shaft 8 to tighten the adjacent divided pieces. Although the diameter of the split ring 1 decreases as the bolt 6 is tightened, the bolt 6 rotates around the rotary shaft 8 to follow this change in diameter.

(4) At the same time, the square washer 11 slides along the engaging surface 9A so that the head of the bolt 6 is smoothly fed to the inner peripheral side, facilitating tightening. After tightening the bolt 6,
The engagement between the inclined engagement surface 9A and the wedge-shaped square washer 11 prevents the head of the bolt 6 from rotating to the outer peripheral side, so that the bolt 6 is unlikely to come off the notch 9.

(5) When the trapezoidal flange 2 is tightened from the outer periphery with the split ring 1 in this way, both structures C2 and C3 are pressed against each other, and sufficient bonding strength is obtained even if a bending load acts on the bonding ends. Can be secured.

(6) On the other hand, when the bolts are to be separated, each bolt 6 is loosened from the state shown in FIGS. 1 and 2 (FIGS. 3 and 4). (7) After loosening the bolt 6 sufficiently, the head of the bolt 6 is rotated to the outer peripheral side to release the engagement with the notch 9, and the split ring 1 is divided into divided pieces.

(8) Then, the divided pieces are removed in the outer peripheral direction to separate the two structures C2 and C3. In this way, when the split ring 1 is removed, the two structures C2 and C3 can be separated and the front structure C2 can be pulled directly above, so that the tip device can be divided even when the reaching shaft is narrow. it can.

(Test Example) In order to confirm the strength of the above-mentioned divided portion structure, a prototype was prepared and a strength test was conducted. As shown in FIG. 5, the test method supported both ends of the tip device joined by the split part structure of the present invention, and applied a load to the central split part to examine the presence or absence of deformation or breakage.

Distance between supporting points (L1): 2 m Operating point distance (L1 / 2): 1 m Load (P1): 48 TON When tested under the above conditions, no deformation or breakage was observed in the prototype. , The normal morphology was retained. The bending moment (M1) at the point of action at this time is: M1 = (1/4) * P1 * L1 = (1/4) * 48 * 2
= 24 TON · m.

For comparison, the bending moment (M2) acting on the divided portion of the tip device when the head of the tip device is extended by the tip jack to control the direction is determined (FIG. 6).

[0034]   Tip jack built-in tip device (F2): 100TON   Direction control angle (θ3): 1.5 °   Distance from head to joint of advanced device (L2): 2m     Bending direction component force (P) = 100TON × sin1.5 ° × cos1.5 °                       = 2.6 TON     Bending moment (M2) acting on the joint of advanced equipment = 2.6TON x 2m                                                     = 5.2TON ・ m

From the above, the split structure of the present invention has a bending moment of about 4.
It was confirmed to have an extremely high strength of 6 times or more.

[0036]

As described above, according to the split structure of the present invention, the flange at the joint end is tightened from the outer periphery by the split ring, so that the split work can be performed even if the reaching shaft is narrow with high bending resistance. be able to.

Further, by making the shape of the flange trapezoidal, the front structure and the rear structure can be pressed against each other, and higher bending resistance can be obtained.

Furthermore, the washer attached to the bolt has a wedge-shaped cross section, and the engaging surface of the notch with which the washer is engaged is also inclined to reduce the diameter of the split ring that occurs when the bolt is tightened, thereby allowing the bolt to rotate. It can be easily followed.

[Brief description of drawings]

FIG. 1A is a plan view showing a joined state of a split portion structure of the present invention, and FIG. 1B is a longitudinal sectional view thereof.

FIG. 2 is a partial cross-sectional view taken along line XX of FIG. 1B.

FIG. 3 (A) is a plan view showing a separated state of the dividing portion structure of the present invention, and FIG. 3 (B) is a longitudinal sectional view thereof.

FIG. 4 is a transverse cross sectional view taken along the line YY of FIG. 3B, showing a state in which the split ring is removed.

FIG. 5 is an explanatory view showing a test method of a strength test of the split portion structure of the present invention.

FIG. 6 is an explanatory diagram for obtaining a bending moment acting on a divided portion of the tip device.

7A and 7B are explanatory views of a pipe laying process of a compaction-free soil-free system using a pipe propulsion tip device, in which (A) is before excavation, (B) is the original push jack extension, and (C) is the original push jack. When retreating,
(D) shows when the tube is attached to the original pushing device.

8A and 8B are explanatory views of a pipe laying process of a compaction-free earth-removal method using a tip device for pipe propulsion, where FIG. 8A is for digging, FIG. 8B is for pushing the original push jack, and FIG. When controlling the direction of
(D) shows when the tip device and the tube are pushed in.

FIG. 9 is an explanatory view of a step of removing the tip device after reaching the reaching shaft, (A) when the tip device reaches the reaching shaft,
(B) shows the removal of the front structure, (C) shows the extrusion of the rear structure into the reaching shaft, and (D) shows the removal of the rear structure.

FIG. 10 shows a conventional structure of a split portion using bolts,
(A) is a longitudinal sectional view and (B) is a lateral sectional view.

FIG. 11 shows a conventional structure of a split portion using a cap nut,
(A) is a longitudinal sectional view and (B) is a lateral sectional view.

12 is a vertical cross-sectional view showing a state in which the tip device of FIG. 11 is divided.

[Explanation of symbols]

1 Split ring 2 Flange 3 Groove 4 O ring
5 groove 6 bolt 7 groove 8 rotary shaft 9 notch 9A engaging surface 10 groove
11 Square washer A Start vertical shaft B Reach vertical shaft C Tip device C1 Head C2 Front structure C3 Rear structure C4 Joining surface D Source pusher D1 Source push jack E Pipe G Bolt H Nut I O ring J Cap nut K O ring M Female thread N Male thread O Flange

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Akio Takashi 1 Taya-cho, Sakae-ku, Yokohama Sumitomo Electric Industries, Ltd. Yokohama Works (72) Inventor Minoru Tanaka 3-19-2 Nishishinjuku, Shinjuku-ku, Tokyo Nihonhon Telegraph and Telephone Corp. (72) Inventor Tetsuya Asano 3-19-2 Nishishinjuku, Shinjuku-ku, Tokyo Japan Telegraph and Telephone Corp. (72) Inventor Junichi Shirakawa 3-18-10 Moto-Asakusa, Taito-ku, Tokyo Within Airec Giken Co., Ltd. (72) Inventor Toshio Akiyama 3-18-10 Moto-Asakusa, Taito-ku, Tokyo Inside Airec Giken Co., Ltd. (56) References: 60-148396 (JP, U) Actual Kaihei 4-73088 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) E21D 9/06

Claims (4)

(57) [Claims] 1. A split part structure of a pipe propulsion tip device for joining and separating a front structure and a rear structure, wherein each structure has a flange portion at a joint end thereof, and is fitted to the flange portion. joining both structures with split ring having a groove for engagement, the split ring is constructed to be freely separated into a plurality of divided pieces, the divided pieces are equipped with a coupling mechanism between the split pieces adjacent coupling mechanism , The rotary shaft attached to one end of each divided piece, and this rotary shaft
A rotatable bolt that is screwed into the
A notch with which the bolt heads of the contacting pieces engage.
The structure of the split part of the tip device for pipe propulsion, characterized by 2. The vertical cross-sectional shape of the flange portion when the front structure and the rear structure are joined together is trapezoidal, and the groove of the split ring has a shape corresponding to this flange portion. 1. The structure of the divided part of the tip device for pipe propulsion according to 1. 3. A washer is fitted under the neck of the bolt,
The washers are not of uniform thickness and have a wedge-shaped cross section.
The divided part structure of the tip device for pipe propulsion according to claim 1, wherein: 4. A washer is fitted under the neck of the bolt,
The engaging surface of the notch with which the washer of
The divided part structure of the tip device for pipe propulsion according to claim 1 .