JPS615194A - Earth auger bit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] The present invention enables efficient excavation in hard rock excavation,
This relates to an earth auger bit that can shorten working time and has a long tool life.

The earth auger has a drive mechanism such as a motor installed on the top.
The earth auger bit, which has an auger head that is generally installed at the tip, is used to excavate foundation holes for buildings and holes for continuous underground walls in the ground. Improvements have been made, such as increasing the chamfer on the cutting edge and shaping the entire bottom of the blade into a digging blade. However, when these earth auger bits are used for long periods of time during rock excavation and are subjected to repeated impacts, contact heat is generated due to contact with the rock due to abrasion of the tip of the cutting edge, and the temperature reaches 200℃ to 800℃, resulting in the contact between the shank and tip. There were many accidents where the soldered parts were misaligned or detached, or due to increased distortion due to heat generation, large parts were damaged and fell off, rendering them unusable.

The present invention has been made to solve the above-mentioned problems, and its gist is that a required number of cemented carbide cylindrical tips are fixed in the longitudinal direction of the shank at the tip of the inclined shank, and the outer insertion tips are attached to the shank. This is an earth auger bit that is inserted from the corner toward the center of the shank.

Note that the number of cylindrical chips is usually plural, but in the case of small-sized chips, it may be one.

Hereinafter, the present invention will be described in detail with reference to the drawings.

Figure 1 shows a schematic diagram of the swagger head part.
The earth auger bit of the present invention is provided at the tip of the earth auger head.

The main part is shown in Figure 2.The tip of the shank (1) is counterbore, and two cylindrical tips made of cemented carbide, typically made of tungsten carbide with cobalt or nickel as a binder, are installed in this counterbore. These cylindrical tips (2) are placed at required intervals in the longitudinal direction of the shank (1), and those placed on the outside are closer to the center of the shank than the shank corners (1a). The other cylindrical tip (2) is inserted from the tip of the shank (1) parallel to the longitudinal direction of the shank, and the periphery of these cylindrical tips (2) is welded with a high hardness welding rod. It is fully welded. The cylindrical chip (2) is fixed by either a press-fit method or a shrink-fit method as described above to eliminate the influence of distortion caused by brazing.

The earth auger bit of the present invention is constructed as described above, and the outer tip (2) of the cylindrical tips (2) is inserted from the shank corner (1a) toward the center of the shank. The cylindrical tips (2) are made to bite smoothly into the rock, and the cylindrical tips (2) are not exposed even if the tip of the shank (1) wears out, extending the life of the tips (2). By welding the ridge, even if the shank (1) is heavily worn, the chip (
2) is designed so that the shank (1) wears out in accordance with the wear of the tip (2) so that the tip (2) does not become exposed.

Furthermore, Figures 5 and 6 are perspective views of conventional earth auger bits, and since the front surface of the bit is the cutting edge (3), as wear progresses, the surface pressure applied to the entire surface of the cutting edge decreases. , drilling efficiency decreases. In addition, if used for a long time, thermal cracks will occur, and this generated heat will reduce the adhesive strength of the brazed portion, causing the chip to separate. Also, if the tool is reversed, the chip is likely to separate.

In contrast, in the earth auger bit of the present invention, the cylindrical tip (2) is firmly fixed to the tip of the shank (1) by press-fitting or shrink-fitting, so there is no effect of distortion due to brazing, and the The power of the hard alloy can be fully demonstrated, and the contact surface with the rock is small, so even if it wears out, sufficient surface pressure will be applied, improving excavation efficiency. In addition, even if the auger screw is reversed, the cylindrical tip (2) is embedded in the shank (1) so it will not come off, and the shank itself can be heat treated on its entire surface, increasing its hardness. Quality and durability can be improved.

As described above, according to the present invention, since the auger bit is formed with a cylindrical tip embedded in the tip of the shank, hard rock layers can be excavated efficiently, the working time can be shortened, and the durability is improved. It exhibits excellent curing properties such as improved hardening.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of the earth auger head, Figure 2 is a perspective view of the earth auger bit of the present invention, Figures 3 and 4 are sectional views taken along lines I-III and II-■ in Figure 2, respectively, and Figure 5 6 and 6 are explanatory diagrams of main parts of a conventional earth auger bit, respectively. In the figure, (1): Shank (2); Cylindrical chip patent applicant Nippon Tungsten Co., Ltd. Agent Noriharu Ariyoshi Procedural amendment (self-restraint)

Claims (1)

[Claims] 1. An earth auger bit in which the required number of cemented carbide cylindrical tips are fixed in the longitudinal direction of the shank at the tip of the slanted shank, and the outer insertion tip is inserted from the corner of the shank toward the center of the shank.