JPH0426560Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to cutter bits used in the shield construction method.

The shield tunneling machine used for subway construction, sewerage construction, etc. has a cylindrical main body 1 as shown in Figure 1.
A rotating body 2 is provided at the front end of the rotating body 2, and cutter bits 5 and leading bits 6 are attached in a row to the front surface of the rotating body 2. The rotating body 2 is provided with an intake port 3 for discharging rock debris, earth and sand, etc. scraped off by the cutter bit 5.

As shown in FIG. 2, the cutter bit 5 is made by brazing a carbide tip 9 to the tip of a steel base metal 7, and its cutting edge ridgeline 9a is formed in a straight line. Further, a pin hole 11 for attachment is bored in the shank portion 10 of the base metal, and the base metal is fixed to the rotating body 2 by a pin inserted through the pin hole. In addition to the pin-fixing type, there are also types that have bolt holes in the base metal and are fixed to the rotating body with bolts, and types that are directly welded to the rotating body. This cutter bit 5 excavates the excavated surface while moving in the direction of arrow A by the rotation of the rotating body 2, but as mentioned above, the cutting edge is formed in a wide straight line, so that
In the case where earthen floors, pine piles, reinforcing bars, etc. are present, excavation cannot be carried out efficiently using only the cutter bit 5. For this reason, as shown in FIG. 3, a carbide tip 1 with a sharp cutting edge is attached to the protruding portion of the base metal 12 whose both end portions protrude forward.
A leading bit 6 formed by soldering 3 is placed side by side with the cutter bit 5 by directly welding it to the rotating body or by providing a shank with a pin hole similar to the cutter bit 5 and fixing it with a pin. According to bit 6, the above-mentioned Dotan, stake,
The reinforcing bars were cut, but using two types of bits with different shapes was uneconomical and undesirable in terms of parts management.

This invention was made in view of the above circumstances, and is intended to provide a cutter bit that can efficiently cut rocks, earth and sand, and cut old piles, reinforcing bars, etc.

In other words, the cutter bit according to the present invention is
A cutter bit that is attached to a rotating body provided at the tip of a shield tunneling machine and performs cutting while moving in the direction of rotation of the cutter bit, and has a main cutting edge made of cemented carbide having a straight front end ridgeline, and the cutting edge. A leading cutting edge made of cemented carbide exhibiting a wedge shape with an acute angle in plan view and projecting forward from the ridge line of the cutter bit, the protruding direction of the leading cutting edge being substantially perpendicular to the moving direction of the cutter bit. There is. The embodiments shown in the drawings will be described below.

FIG. 4 shows an example of a cutter bit according to the present invention, and this cutter bit 20 has a cemented carbide chip 22 on the cutting edge of a base metal 21 made of special steel.
A shank portion 24 having a pin hole 23 for attachment is integrally provided at the rear of the base metal 21. The cutting edge E of the cemented carbide chip includes a main cutting edge ME having a linear ridgeline, and a main cutting edge ME having a linear ridgeline.
It consists of a leading cutting edge PE that has a pointed tip (with a chamfer C) that is triangular in plan view and protrudes forward from the center of the ME. The lower portion of the cutting edge E, which is the front end surface of the base metal 21, is formed as an inclined surface whose lower side escapes rearward. FIG. 5 shows a different embodiment from the above, in which two leading cutting edges PE each having a sharp tip are provided.
A shank portion 24 similar to the previous example is provided at the rear of the base metal, and a pin hole 23 is bored through this.

The cutter bit 20 according to the present invention has a shank portion 2 attached to a groove-shaped seat 36 of a holder 35 as shown in FIG.
4 and inserting a pin 37 made of, for example, stainless steel into the pin hole 39 of the holder 35 and the pin hole 23 provided in the shank portion 24, the rotating body 2
can be attached to. FIG. 7 is an external view of a shield excavator in which a plurality of cutter bits 20 are installed in a row on the frame 2a of the rotating body 2 in this way, and the leading bit 6 as shown in FIG. 1 is not attached. do not have. By pressing the rotating body 2 of this excavator against the excavation surface while rotating, the cutter bit moves in a predetermined direction and excavation is performed. During excavation, Katsutabitsu is shown in Figure 4a,
It moves upward in FIG. 5a, and the direction of movement is approximately perpendicular to the direction in which the leading cutting edge PM protrudes. Dotan, old piles, etc. are scratched and cut by this leading cutting blade part PM. The earth and sand scraped off by Katsuturbit 20 are removed from the intake port 3.
It is taken into the main body 1 and sequentially discharged to the rear. As is clear from the above explanation, the cutter bit according to the present invention has, in addition to the main cutting edge ME having a linear ridgeline for scraping off dirt and the like and sending it to the intake port, Leading cutting edge made of cemented carbide that has a wedge shape with an acute angle when viewed from above.
Equipped with a PE, the protruding direction of the leading cutting edge is almost perpendicular to the direction of movement of the cutter bit, making it possible to easily cut clay, old piles, reinforcing bars, etc., if present on the excavation surface. Therefore, it has become possible to proceed with the excavation work efficiently without having to specially provide a leading bit as in the past. The shape of the leading cutting edge PE is not limited to the illustrated example, but may be of any shape as long as it can efficiently cut piles and the like.

[Brief explanation of the drawing]

Figures 1 and 7 are perspective views of the shield tunneling machine, and Figures 2 and 3 are explanatory views of conventionally used cutter bits, where a is a side view, b is a plan view, and c is a front view. It is a diagram. FIG. 4 is a side view showing an example of the cutter bit according to the present invention;
FIG. 5 is a side view, b is a plan view, and c is a front view showing different embodiments. Further, FIG. 6 is a perspective view of the cutter bit mounting portion. 1...Main body, 2...Rotating body, 3...Intake port, 6
...Advance bit, 20...Katsuter bit, 21
...Base metal, 22...Cemented carbide chip, 23...Pin hole, 24, 24'...Shank part, E...Cutting edge part, ME...Main cutting edge part, PE...Preceding cutting edge part .

Claims (1)

[Scope of utility model registration request] A cutter bit that is attached to a rotating body provided at the tip of a shield tunneling machine and performs cutting while moving in the direction of rotation of the cutter bit, and has a main cutting edge made of cemented carbide having a straight front end ridgeline, and the main cutting edge. A leading cutting edge made of cemented carbide having a wedge shape with an acute angle in plan view and projecting forward from the ridgeline of the cutter bit, and the projecting direction of the leading cutting edge is substantially perpendicular to the moving direction of the cutter bit. Katsutabitsuto.