JPH07552Y2 - Cutting tool for pipe propulsion device - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a cutting tool for a pipe propulsion device for moving a propulsion pipe and a casing rod incorporated therein from a starting shaft to a reaching shaft. is there.

[Conventional technology]

As shown in FIG. 6 and FIG. 7, a propulsion device main body 3 is mounted on a slide base 2 provided on the bottom surface of the starting shaft 1, and a propulsion jack 4 for moving the propulsion device main body 3 back and forth along the slide base 2. A motor M and a cylindrical chuck 5 rotatably driven by the motor M are attached to the propulsion device main body 3, and a spindle rod 6 having a rear end inserted inside the chuck 5 is held by the chuck 5. Then, the casing rod 7 is connected to the spindle rod 6, and the rear end portion of the propulsion pipe 8 inserted outside the casing rod 6 is brought into contact with the push ring 9 provided on the front side of the propulsion device main body 3 so that the motor 5 BACKGROUND ART A pipe propulsion device has been conventionally known in which the casing rod 7 is rotated by driving and the casing rod 7 and the propulsion pipe 8 are press-fitted into the ground by the movement of the propulsion device main body 3.

In the above-mentioned pipe propulsion device, the cutting tool A is attached to the tip of the casing rod 7, and the ground material is cut by the cutting tool A by the rotation of the casing rod 7.

FIG. 8 and FIG. 9 show a conventional cutting tool A, in which axial holes 11 are provided at required intervals in the circumferential direction of a head ring 10 fixed to the tip of a casing rod 7, and each hole 11 A shaft 13 provided on the back surface of the cutting bit 12 is rotatably inserted therein, and a state in which one end of the cutting bit 12 projects outward from the outer diameter surface of the head ring 10 at the tip surface of the head ring 10 and the head ring. A configuration is provided in which a stopper 14 that allows the cutting bit 12 to freely rotate between a state in which it is housed inside the outer diameter surface of 10 is provided.

In the above cutting tool A, cutting work is performed in a state where the cutting bit 12 abuts on the stopper 14 and one end of the cutting tool 12 projects outwardly from the outer diameter surface of the head ring 10. The cutting bit 12 is worn and needs to be replaced. In this case, rotate the head ring 10 together with the casing rod 7 in the direction of the arrow in FIG.
As shown in FIG. 10, each cutting bit 12 is rotated about the shaft 13 so as to be accommodated in the tip end surface of the head ring 10, and then the casing rod 7 is pulled out from the inside of the propulsion pipe 8 to cut the cutting bit 12. Will be exchanged.

[Problems to be solved by the device]

By the way, the conventional cutting tool A does not have a rotation preventing means for preventing the cutting bit 12 from falling inward in the cutting state. In some cases, the cutting tool 10 may be accommodated within the tip surface of the cutting tool 10, and the tilting of the cutting bit 10 causes inconvenience that the cutting process cannot be efficiently performed.

It is a technical object of the present invention to eliminate the above-mentioned inconvenience and to reliably hold a cutting bit in a cutting state.

[Means for Solving the Problems]

In order to solve the above problems, in the present invention, the shaft of the cutting bit inserted into the hole of the head ring is slidably supported by a predetermined stroke, and the outer surface of the head ring is provided on the rear surface of one end of the cutting bit. A projecting portion that can be engaged with is provided, and the projecting length of the projecting portion is smaller than the slide amount of the shaft.

[Action]

With the above configuration, it is possible to prevent the cutting bit from falling inward due to the engagement of the protruding portion with the outer diameter surface of the ring, and it is possible to reliably hold the cutting bit in the cutting state.

When exchanging the cutting bit due to wear or the like, the casing rod with the head ring fixed is pulled from the propulsion pipe, one end of the cutting bit is brought into contact with the tip of the propulsion pipe to stop the cutting bit, and The relative movement of the casing rod with respect to the cutting bit releases the engagement between the protrusion and the outer diameter surface of the ring, and then the casing rod is rotated in the direction opposite to the rotation direction during cutting to move each cutting bit inward. Tilt it down and pull out the casing rod from the propulsion pipe.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

As shown in the figure, a head ring 20 is fixed to the tip of a casing rod 7 incorporated inside the propulsion pipe 8 via means such as welding.

A plurality of holes penetrating in the axial direction in the circumferential direction of the head ring 20.
21 are formed at required intervals, and a shaft 23 provided on the back side of the cutting bit 22 is inserted into each hole 21 so as to be rotatable and slidable in the axial direction.

The rear end of the shaft 23 projects from the hole 21 to the back side of the head ring 20, and an engaging groove 24 is provided at the rear end. A retaining ring 25 for preventing the shaft 23 from coming off is attached to the engaging groove 24,
The shaft 23 is slidable within a space formed between the retaining ring 25 and the back surface of the head ring 20.
l ₁ indicates the slide amount of the shaft 23.

A small-diameter shaft portion 26 is formed in the middle of the shaft 23, and an elastic ring 27, part of which has been cut off, is fitted to the outside of the small-diameter shaft portion 26. The elastic ring 27 is in pressure contact with the inner diameter surface of the hole 21, and the pressure contact prevents the shaft 23 from moving smoothly in the axial direction. The elastic ring 27 also prevents the shaft 23 from moving smoothly in the axial direction.

The head ring 20 is provided on the rear side of one end of the cutting bit 22.
Is formed with a protrusion 28 engageable with the outer diameter surface of the
The protruding length l ₂ of 28 is smaller than the sliding amount l _{1 of the} shaft 23.

A stopper 29 is fixed to the front end surface of the head ring 20 on the back side of each cutting bit 22. The stopper 29 has two stopper surfaces 30 and 31, and one end surface of the cutting bit 22 contacts the stopper surface 30 while the cutting bit 22
Is held in a state in which one end thereof projects outward from the outer diameter surface of the head ring 20. Further, the cutting bit 22 is held in a state of being housed inside the outer diameter of the head ring 20 in a state where the rear end portion of the one side surface of the cutting bit 22 contacts the other stopper surface 31.

The cutting tool shown in the embodiment has the above-mentioned structure, and FIGS. 1 and 2 show the cutting state of the cutting tool. One end of the cutting bit 22 projects outward from the outer diameter surface of the head ring 20, and The protruding portion 28 engages with the outer diameter surface of the head ring 20 to hold the cutting bit 22 in a cutting state.

When replacing the cutting bit 22 due to wear or the like, the operation of pulling the casing rod 7 and the casing rod 7
To rotate in a direction opposite to the rotation direction during cutting.

Here, when the casing rod 7 is pulled, one end of the cutting bit 22 comes into contact with the tip of the propulsion pipe 8 and stops, and the casing rod 7 moves axially relative to the stopped cutting bit 22. , As shown in FIG. 4, the head ring 20
The back surface of the abuts against the retaining ring 25.

Since the relative movement amount of the head ring 20 and the casing rod 7 is larger than the protruding length l _{2 of} the protruding portion 28, the engagement between the protruding portion 28 and the outer diameter surface of the head ring 20 is released. In the disengaged state, when the casing rod 7 is rotated in the direction opposite to the rotating direction at the time of cutting, the cutting bit 22 that comes into contact with the ground 22
The casing rod 7 rotates relative to the cutting rod 22, and each cutting bit 22 hits the stopper surface 31, as shown in FIG.
The head ring 20 is stored inside the outer diameter surface.

Therefore, the casing rod 7 can be pulled from the propulsion pipe 8. By pulling out the casing rod 7, the cutting bit 22 can be replaced outside.

After the replacement, with one side of each cutting bit 22 in contact with the stopper surface 31, the casing rod 7 is moved to the propelling pipe 8.
Inserting the casing rod 7 into the inside of the car and inserting the casing rod 7 to the position where the cutting bit 22 at the tip comes into contact with the ground, the casing rod 7 is rotated in the cutting direction, and the cutting bit 22 comes into contact with the ground and is in a stopped state. The casing rod 7 is further rotated in the axial direction with one side surface of the cutting bit 22 abutting against the stopper surface 30 by rotating the casing rod 7 relative to the outer circumference of the head ring 20. Engage the surface.

[Effect of device]

As described above, in the cutting tool according to the present invention, the protrusion provided on the rear surface of the one end of the cutting bit is engaged with the outer diameter surface of the head ring. Therefore, the cutting work can be effectively performed.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view showing an embodiment of a cutting tool according to the present invention, FIG. 2 is an enlarged sectional view showing a main part of the same, FIG. 3 is a side view of the same, and FIG. Fig. 5 is a sectional view showing an operating state of the same as above, Fig. 5 is a side view showing a storing state of the above cutting bit, Fig. 6 is a front view of a pipe propulsion device, Fig. 7 is a vertical sectional front view of the same, and Fig. 8 is FIG. 9 is a sectional view showing a conventional cutting tool, FIG. 9 is a side view showing the same, and FIG. 10 is a side view showing an operating state of the same. 7 …… Casing rod, 20 …… Head ring, 21 ……
Hole, 22 ... cutting bit, 23 ... shaft, 25 ... retaining ring, 28 ...
… Projection, 29 …… Stopper.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Hirao 1-22-25 Teizukayama, Abeno-ku, Osaka-shi, Osaka (56) References JP-A-63-55296 (JP, A)

Claims (1)

[Scope of utility model registration request] 1. A shaft provided with a head ring fixed to the tip of a casing rod, and axially formed with insertion holes in the circumferential direction of the head ring at required intervals, each shaft being provided on the back surface of a cutting bit. Is rotatably inserted, and one end of the cutting bit projects outward from the outer diameter surface of the head ring and the entire cutting bit is housed inside the outer diameter surface of the head ring on the front surface of the head ring. In a cutting tool of a pipe propulsion device provided with a stopper that allows the cutting bit to freely rotate between a state and a state, a shaft of the cutting bit is slidably supported by a predetermined stroke, and a head ring is provided on the back side of one end of the cutting bit. Providing a protrusion that can be engaged with the outer diameter surface of
A cutting tool for a pipe propulsion device, wherein a protruding length of the protruding portion is smaller than a sliding amount of a shaft.