【考案の詳細な説明】
(イ) 技術分野
考案は岩盤、硬土層をボーリングするためのア
ースオーガーヘツドの掘削刃の改良に関するもの
である。[Detailed explanation of the invention] (a) Technical field The invention relates to the improvement of the digging blade of an earth auger head for boring through bedrock and hard soil layers.
(ロ) 技術の背景
岩盤、硬土層の掘削するための土木機械として
ロツクビツト、アースオーガーヘツドが用いられ
ているが、この刃先には耐摩耗性の高い超硬合金
製チツプが使用されている。そしてその超硬合金
製チツプの形状には種々の工夫がなされている。
これは掘削効率の向上のためであり長寿命で取換
えサイクルの長いものが望まれている。第１図は
アースオーガーヘツドの一例を示すものであり回
転軸に沿つて回転翼があり、その先端に掘削刃２
が複数箇装着されている。このヘツドはＰの方向
に回転しつつ掘削を進めるが、最も衝撃と摩耗を
受ける掘削刃２の摩耗、破損は甚だしいものがあ
る。従来の掘削刃の形状の例として第２図イに示
すものがある。この形状の掘削刃は刃先４を介し
て岩盤、硬土盤等を掘削する場合、刃先に集中的
な荷重を与え、岩盤等にクラツクを生ぜしめつつ
掘削が行われる。そして掘削が進むにつれて先端
部の摩耗が著しく頂角部４′は丸くなり第２図ロ
の如くなつて岩盤への喰い込み効果が低下し掘削
速度が著しく低下してしまい、刃先を取換えざる
を得なくなる。(b) Background of the technology Rock bits and earth auger heads are used as civil engineering machines to excavate rock and hard soil layers, and their cutting edges are made of highly wear-resistant cemented carbide. . Various improvements have been made to the shape of the cemented carbide chip.
This is to improve excavation efficiency, and a long life and long replacement cycle is desired. Figure 1 shows an example of an earth auger head. There are rotor blades along the axis of rotation, and a cutting blade 2 at the tip.
Multiple pieces are installed. This head excavates while rotating in the direction of P, but the excavating blade 2, which receives the most impact and wear, is subject to severe wear and damage. An example of the shape of a conventional digging blade is shown in FIG. 2A. When excavating rock, hard soil, etc. through the cutting edge 4, the excavating blade having this shape applies a concentrated load to the cutting edge, causing cracks in the rock, etc. while excavating. As the excavation progresses, the tip wears out and the apex 4' becomes rounded, as shown in Figure 2 (B), resulting in a decrease in the effectiveness of biting into the rock and a significant drop in excavation speed, making it necessary to replace the cutting edge. You won't get any more.
(ハ) 考案の開示
本考案によるアースオーガー用掘削刃は第３図
にその１例を示す如く、刃先部の傾斜部３に丸み
をつけた溝６を設けたことを特徴とする。この溝
は傾斜部３のみにつけてもよく５の両方に設けて
もよい。この形状にすれば、これが硬土盤又は岩
盤に喰い込んだ状態はおよそ第５図に示す如く、
削られた土砂、掘削屑１２は刃先すくい面に沿つ
て押上げるだけでなく、矢印Ｒの方向へも押し上
げられる。この土砂、掘削屑の流れによつて刃先
の尖頭形状をシヤープに保持させることができ、
刃先の荷重集中を持続させ、その結果掘削能率を
従来のものより長く保持させることができるもの
である。傾斜面の溝の丸みのＲは土質によつて適
当に設定すればよく、従来の各種の形状の掘削刃
に適用できる。第４図は本考案による掘削刃の
種々の実施例を示す掘削刃の斜視図である。イ，
ロは刃先４がＲになつており、傾斜面（すくい
面）にイは全長にわたつて溝を設けた例。ロは全
長にいたらず途中で切上げた形である。第４図
ハ，ニは刃先４が面取した形状の掘削刃であり、
ハはＲの小さい溝、ニはＲが大きく傾斜面全体に
溝を形成したものである。以上述べた本考案の掘
削刃は、掘削土砂、岩屑の排出を利用して刃先の
シヤープニングを行わせしめ、刃先突起を長時間
保持させて掘削速度の低下を防止し、掘削時間を
短縮、取換え時間の延長などにより掘削コストを
低減する上で効果が大きい。(C) Disclosure of the Invention The excavating blade for an earth auger according to the present invention is characterized in that a rounded groove 6 is provided in the inclined portion 3 of the cutting edge, as shown in FIG. This groove may be provided only on the inclined portion 3 or may be provided on both of the inclined portions 5. With this shape, the state in which it bites into hard soil or bedrock will be approximately as shown in Figure 5.
The scraped earth and sand and excavated debris 12 are not only pushed up along the rake surface of the cutting edge, but also pushed up in the direction of arrow R. This flow of earth and sand and excavation debris allows the sharp to maintain the pointed shape of the cutting edge.
This allows the load to continue to concentrate on the cutting edge, and as a result, excavation efficiency can be maintained for a longer period of time than conventional methods. The radius R of the groove on the slope may be appropriately set depending on the soil quality, and it can be applied to conventional excavation blades of various shapes. FIG. 4 is a perspective view of a digging blade showing various embodiments of the digging blade according to the present invention. stomach,
B is an example in which the cutting edge 4 is rounded, and A is an example in which a groove is provided over the entire length on the inclined surface (rake face). B is not the full length, but rounded up in the middle. Figure 4 C and D are excavation blades with a chamfered cutting edge 4,
C is a groove with a small radius, and D is a groove with a large radius formed over the entire slope surface. The excavation blade of the present invention as described above uses the discharge of excavated soil and rock debris to perform shear-punching of the cutting edge, retains the protrusion of the cutting edge for a long time, prevents a decrease in excavation speed, and shortens excavation time. This is highly effective in reducing excavation costs by extending replacement time.
【図面の簡単な説明】[Brief explanation of the drawing]
第１図は本考案の対象であるアースオーガーヘ
ツドの正面図、第２図は従来のアースオーガーヘ
ツド用掘削刃の正面図、第３図は本考案の掘削刃
の正面図、第４図は本考案の実施例の掘削刃の斜
視図及び第５図は本考案の掘削刃による掘削状況
を示す図である。
１：回転翼、２：掘削刃、３：すくい面（傾斜
面）、４：刃先、５：傾斜面、６，７，８，９，
１０：溝、１１：岩盤、１２：掘削屑。
Figure 1 is a front view of the earth auger head that is the object of the present invention, Figure 2 is a front view of a conventional digging blade for earth auger heads, Figure 3 is a front view of the digging blade of the present invention, and Figure 4 is a front view of the earth auger head of the present invention. A perspective view of the excavation blade according to the embodiment of the present invention and FIG. 5 are diagrams showing an excavation situation by the excavation blade of the present invention. 1: Rotary blade, 2: Drilling blade, 3: Rake face (slanted surface), 4: Cutting edge, 5: Slanted surface, 6, 7, 8, 9,
10: Groove, 11: Rock, 12: Excavation debris.