JPH0316954Y2 - - Google Patents
Info
- Publication number
- JPH0316954Y2 JPH0316954Y2 JP7620486U JP7620486U JPH0316954Y2 JP H0316954 Y2 JPH0316954 Y2 JP H0316954Y2 JP 7620486 U JP7620486 U JP 7620486U JP 7620486 U JP7620486 U JP 7620486U JP H0316954 Y2 JPH0316954 Y2 JP H0316954Y2
- Authority
- JP
- Japan
- Prior art keywords
- bit
- hole
- gravel
- ground
- drilling
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000005553 drilling Methods 0.000 claims description 18
- 230000007423 decrease Effects 0.000 claims description 7
- 239000004576 sand Substances 0.000 claims description 5
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- VNTLIPZTSJSULJ-UHFFFAOYSA-N chromium molybdenum Chemical compound [Cr].[Mo] VNTLIPZTSJSULJ-UHFFFAOYSA-N 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000004570 mortar (masonry) Substances 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
Landscapes
- Earth Drilling (AREA)
Description
〔産業上の利用分野〕
この考案は砂礫地盤に孔を穿設するための削孔
用ビツトに関するものである。
〔従来技術〕
地盤の垂直法面を安定させる工法として、その
垂直法面から地盤にほぼ水平な孔を穿設し、その
孔にロツクボルトを挿入すると共に、そのロツク
ボルトと孔壁との間にモルタルを注入充填する工
法が知られている。
従来、地盤に40〜60mmの孔径の孔を穿設する場
合、地盤が軟質であるときは、オーガースクリユ
ーによる削孔を行ない、また地盤が砂礫質や岩質
であるときは、第10図および第11図に示すよ
うに、ビツト先端側が拡大しているビツト本体6
の前端部に超硬合金の切削用チツプ7を埋込固定
して構成したクローラー用ビツト8を、レツグ付
きドリルまたはクローラードリル等の回転衝撃式
ドリルのロツドに取付けて、そのクローラー用ビ
ツト8により削孔するのが通例である。
〔考案が解決しようとする問題点〕
しかし、砂礫質の地盤にオーガースクリユーに
よる削孔を行なう場合、孔径以上の大きさの礫に
遭遇したときはその礫を排出することができない
ので削孔が不可能になる。また前記クローラー用
ビツト8を使用して砂礫地盤に対する削孔を行な
う場合、そのビツト8の前端部が砂礫地盤中にあ
る30〜200mmの大径の礫に突き当たつたとき、そ
の礫はビツト8により破砕されるが、第12図に
示すように、破砕された礫が孔外に排出されない
で、ビツト8により回転されながら孔の前部また
は周囲に押付けられるので、孔壁が乱されると共
に孔径が拡大されるという問題がある。
また第13図に示すように、礫9の一部がビツ
ト8の前端縁部に接触した場合、その礫9が破砕
されないで、逆に地山に密着していた礫9の周囲
がビツト8の回転により緩められ、第14図に示
すようにビツト8が通過したのちその礫9および
砂が孔内に崩落して孔詰まりが発生し、そのため
削孔終了後にビツトを引き抜くとき、崩落した砂
礫により引抜きが困難あるいは不可能になること
がある。
さらにまた、削孔長が長い場合例えば2m以上
である場合、第15図を示すように、ビツトの前
端部に礫が接触すると、削孔速度が一時的に低下
して、回転衝撃式ドリルに大きな負荷が作用し、
かつ第15図に鎖線で示すようにロツド10に撓
みが発生してビツト8に方向の狂いが生じ、第1
6図に示すようにビツト8がこれに接触している
礫9を避けて蛇行しながら削孔することになる。
したがつて、穿設された孔は上下あるいは左右方
向に彎曲するので、削孔終了後のビツトの引抜き
が困難あるいは不可能になり、かつロツクボルト
やグラウト注入用パイプの挿入も困難あるいは不
可能になる。
〔考案の目的、構成〕
この考案は前述の問題を有利に解決できる砂礫
地盤削孔用ビツトを提供することを目的とするも
のであつて、この考案の要旨とするところは、ロ
ツドの先端に連結されるビツト本体1が、中間部
から前端に向かつて縮径する前部テーパー部分2
と中間部から後端に向かつて縮径する後部テーパ
ー部分3とを備え、ビツト本体1の前端部に半径
方向に延長する複数の超硬合金の切削用チツプ4
が埋込固定され、前記前部テーパー部分2の側面
に、前後方向に延長する側面噴気溝5が設けら
れ、前記ビツト本体1には、前部テーパー部分2
の前端中央および側面噴気溝5内に開口する送気
孔が設けられていることを特徴とする砂礫地盤削
孔用ビツトにある。
〔実施例〕
次にこの考案を図示の例によつて詳細に説明す
る。
第1図ないし第4図はこの考案の一実施例に係
る砂礫地盤削孔用ビツト17を示すものであつ
て、クロムモリブデン鋼(SCM435)などの特殊
合金からなるビツト本体1が、中間部から前端に
向かつて縮径する前部テーパー部分2と、中間部
から後端に向かつて縮径する後部テーパー部分3
とを備え、前部テーパー部分2の前端部の直径は
ビツト本体1の中間部の最大径の約1/2に設定さ
れ、かつ後部テーパー部分3の後端部の直径は、
ビツト本体1の中間部の最大径と前部テーパー部
分2の前端部の直径との中間値に設定されてい
る。
前記ビツト本体1の後部中央には、回転衝撃式
さく岩機のロツド10の先端部に螺合される雌ね
じ孔11が設けられ、かつビツト本体1の前端部
には、半径方向に延長しかつV字状刃を有する複
数の超硬合金の切削用チップ4が等間隔で配置さ
れて埋込固定され、さらに前部テーパー部分2の
側面には、前後方向に延長する複数の超硬合金の
ビツト本体摩耗防止用チツプ12が等角度間隔で
配置されて埋込固定されている。
前記ビツト本体1に、後端部がロツド10の送
気孔13に連通すると共に前端部がビツト本体1
の前端中央部に開口している噴気孔14が設けら
れ、かつ前部テーパー部分2の周囲には、隣り合
うビツト本体摩耗防止用チツプ12の中間におい
て前後方向に延長する側面噴気溝5が設けられ、
前記噴気孔14と各側面噴気孔14と各側面噴気
溝5の前端側の溝底部とは傾斜送気孔15を介し
て接続され、その傾斜送気孔15は噴気孔14か
ら離れるにしたがつて後方に偏位するように傾斜
している。また前部テーパー部分2の前端部に
は、隣り合う切削用チツプ4の中間において半径
方向に延長する溝16が設けられ、その溝16の
外端部は前記側面噴気溝5に連通している。
第5図に示すように、この考案のビツト17を
回転式衝撃式ドリルのロツド10に取付けて、そ
のビツトに回転および衝撃を与えながら、ビツト
を砂礫地盤中に推進して横孔を穿設する場合、ビ
ツト本体1の前端部の切削用チツプ4により砂礫
地盤が切削され、切削された砂礫は、側面噴気溝
5内に侵入し、次いで傾斜送気孔15から側面噴
気溝5内に供給される圧縮空気により側面噴気溝
5内をビツト本体1の中間最大径部分に向かつて
移送されると共に、回転されながら前進移動され
るビツト本体1により孔壁に押付けられ、さらに
前部テーパー部分2の前端側の周囲の地山は回転
されながら前進移動される前部テーパー部分2に
より外周方向に圧縮され、孔壁が圧密されるの
[Industrial Application Field] This invention relates to a drilling bit for drilling holes in sandy and gravel ground. [Prior art] As a construction method for stabilizing the vertical slope of the ground, a substantially horizontal hole is drilled into the ground from the vertical slope, a locking bolt is inserted into the hole, and mortar is placed between the locking bolt and the hole wall. A method of injecting and filling is known. Conventionally, when drilling a hole with a diameter of 40 to 60 mm in the ground, if the ground is soft, an auger screw is used to drill the hole, and if the ground is sandy or rocky, the hole in Figure 10 is used. As shown in FIG. 11, the bit body 6 has an enlarged tip end.
A crawler bit 8 consisting of a cemented carbide cutting tip 7 embedded and fixed in the front end of the drill is attached to the rod of a rotary impact drill such as a leg drill or a crawler drill, and the crawler bit 8 It is customary to drill a hole. [Problem that the invention aims to solve] However, when drilling a hole in sandy and gravelly ground using an auger screw, if gravel larger than the hole diameter is encountered, the gravel cannot be ejected, so the drilling is stopped. becomes impossible. Furthermore, when drilling a hole in sandy and gravel ground using the crawler bit 8, when the front end of the bit 8 hits a large diameter gravel of 30 to 200 mm in the sandy and gravel ground, the gravel will become a bit. However, as shown in Fig. 12, the crushed gravel is not discharged from the hole, but is rotated by the bit 8 and pressed against the front part of the hole or around the hole, disturbing the hole wall. At the same time, there is a problem that the pore diameter is enlarged. Further, as shown in FIG. 13, when a part of the gravel 9 comes into contact with the front edge of the bit 8, the gravel 9 is not crushed, and on the contrary, the surrounding area of the gravel 9 that was in close contact with the ground becomes the bit 8. As shown in Fig. 14, after the bit 8 passes, the gravel 9 and sand collapse into the hole, clogging the hole. Therefore, when the bit is pulled out after drilling, the collapsed sand and gravel This may make extraction difficult or impossible. Furthermore, when the drilling length is long, for example 2 m or more, as shown in Figure 15, if gravel comes into contact with the front end of the bit, the drilling speed will temporarily decrease and the rotary impact drill will A large load acts on the
In addition, as shown by the chain line in FIG. 15, the rod 10 is bent, causing the bit 8 to become misoriented.
As shown in FIG. 6, the bit 8 is drilled in a meandering manner, avoiding the gravel 9 that is in contact with it.
Therefore, the drilled hole is curved vertically or horizontally, making it difficult or impossible to pull out the bit after drilling, and also making it difficult or impossible to insert a lock bolt or grouting pipe. Become. [Purpose and structure of the invention] The purpose of this invention is to provide a bit for drilling in sandy and gravel ground that can advantageously solve the above-mentioned problems. The bit body 1 to be connected has a front tapered part 2 whose diameter decreases from the middle part toward the front end.
and a rear tapered portion 3 whose diameter decreases from the intermediate portion toward the rear end, and a plurality of cemented carbide cutting tips 4 extending in the radial direction at the front end of the bit body 1.
is embedded and fixed, and a side jet groove 5 extending in the front-rear direction is provided on the side surface of the front tapered portion 2, and the front tapered portion 2 is embedded in the bit body 1.
This bit is characterized by having an air supply hole opening in the center of the front end and in the side blower groove 5. [Example] Next, this invention will be explained in detail using illustrated examples. Figures 1 to 4 show a bit 17 for drilling in gravel ground according to an embodiment of this invention, in which a bit body 1 made of a special alloy such as chromium molybdenum steel (SCM435) is inserted from the middle part. A front tapered portion 2 whose diameter decreases toward the front end, and a rear tapered portion 3 whose diameter decreases from the middle portion toward the rear end.
The diameter of the front end of the front tapered part 2 is set to about 1/2 of the maximum diameter of the middle part of the bit body 1, and the diameter of the rear end of the rear tapered part 3 is
The diameter is set to be an intermediate value between the maximum diameter of the middle part of the bit body 1 and the diameter of the front end of the front tapered part 2. A female threaded hole 11 is provided at the center of the rear part of the bit body 1, and the female screw hole 11 is screwed into the tip of the rod 10 of a rotary impact type rock drill, and the front end of the bit body 1 is provided with a female screw hole 11 extending in the radial direction. A plurality of cemented carbide cutting tips 4 having V-shaped blades are embedded and fixed at regular intervals, and a plurality of cemented carbide cutting tips 4 extending in the front and back direction are embedded and fixed on the side surface of the front tapered portion 2. Chips 12 for preventing wear of the bit body are embedded and fixed at equal angular intervals. The bit body 1 has a rear end that communicates with the air supply hole 13 of the rod 10, and a front end that communicates with the bit body 1.
A blowhole 14 is provided which is open at the center of the front end of the bit body, and a side blowhole groove 5 is provided around the front tapered portion 2 and extends in the front-rear direction between adjacent tips 12 for preventing wear of the bit body. is,
The fumarole hole 14 , each side fumarole hole 14 , and the groove bottom on the front end side of each side fumarole groove 5 are connected through an inclined air supply hole 15 , and the inclined air supply hole 15 moves backward as it moves away from the fumarole hole 14 . It is tilted so that it deviates to . Furthermore, a groove 16 extending in the radial direction between adjacent cutting tips 4 is provided at the front end of the front tapered portion 2, and the outer end of the groove 16 communicates with the side jet groove 5. . As shown in Fig. 5, the bit 17 of this invention is attached to the rod 10 of a rotary impact drill, and while rotating and applying impact to the bit, the bit is propelled into the gravel ground to drill a horizontal hole. In this case, the gravel ground is cut by the cutting tip 4 at the front end of the bit body 1, and the cut gravel enters the side fumarole groove 5, and is then supplied into the side fumarole groove 5 from the inclined air supply hole 15. The compressed air is transferred inside the side jet groove 5 toward the middle maximum diameter part of the bit body 1, and is pressed against the hole wall by the bit body 1, which is rotated and moved forward, and is further pressed against the hole wall in the front tapered part 2. The surrounding ground on the front end side is compressed in the outer circumferential direction by the front tapered part 2, which is rotated and moved forward, and the hole wall is consolidated.
この考案によれば、ビツトに回転および衝撃を
与えながら、そのビツトを砂礫地盤中に推進して
削孔する場合、ビツト本体1の前端部の切削用チ
ツプ4により砂礫地盤が切削され、切削された砂
礫は、側面噴気溝5内に侵入し、次いで傾斜送気
孔15から側面噴気溝5内に供給される圧縮空気
により側面噴気溝5内をビツト本体1の中間最大
径部分に向かつて移送されると共に、回転されな
がら前進移動されるビツト本体1により孔壁に押
付けられ、さらに前部テーパー部分2の前端側の
周囲の地山は回転されながら前進移動される前部
テーパー部分2により外周方向の圧縮され、孔壁
が圧密されるので、ビツトの先端部の地山を攬乱
することなく、かつ孔壁に強度を増大させて孔壁
の崩落を防止しながら削孔することができ、さら
に礫の一部が前部テーパー部分2の前端縁部に接
触した場合は、回転されながら前進移動する前部
テーパー部分2により、前記礫を孔壁の地山に圧
入して、孔内への礫の崩落を防止することがで
き、そのため円形断面で直線状の孔を容易に穿設
することができ、また削孔終了後にビツトを引抜
く場合、孔内に礫の一部が突出していることがあ
つても、ビツトを回転させながら引抜くことによ
り、その礫を後部テーパー部分3により孔壁に押
込んで、円孔の孔を形成することができる等の効
果が得られる。
According to this invention, when drilling a hole by propelling the bit into gravelly ground while rotating and applying impact, the cutting tip 4 at the front end of the bit body 1 cuts the gravelly ground. The sand and gravel enters the side fumarole groove 5, and is then transported within the side fumarole groove 5 toward the middle maximum diameter portion of the bit body 1 by compressed air supplied into the side fumarole groove 5 from the inclined air supply hole 15. At the same time, the ground around the front end side of the front tapered part 2 is pressed against the hole wall by the bit body 1, which is rotated and moved forward. is compressed and the hole wall is consolidated, so the hole can be drilled without disturbing the ground at the tip of the bit and while increasing the strength of the hole wall and preventing the hole wall from collapsing. Furthermore, when some of the gravel comes into contact with the front edge of the front tapered part 2, the front taper part 2, which moves forward while being rotated, presses the gravel into the ground of the hole wall and into the hole. Therefore, it is possible to easily drill a straight hole with a circular cross section, and when the bit is pulled out after drilling, there is no possibility that some of the gravel will protrude into the hole. Even if there is some gravel, by pulling it out while rotating the bit, the rear tapered portion 3 can push the gravel into the hole wall to form a circular hole.
第1図ないし第4図はこの考案の一実施例に係
る砂礫地盤削孔用ビツトを示すものであつて、第
1図は側面図、第2図は正面図、第3図は第2図
のA−A線断面図、第4図は第2図のB−B線断
面図である。第5図はこの考案のビツトを使用し
て削孔している状態を示す縦断側面図、第6図は
この考案のビツトの前端縁部が礫に突き当たつた
状態を示す縦断側面図、第7図はそのビツトの前
部テーパー部分が礫を孔壁の地山に押込んで通過
するときの状態を示す縦断側面図、第8図はこの
考案のビツトを引抜くとき孔壁から突出している
礫がビツトの後部テーパー部分に突き当たつた状
態を示す縦断側面図、第9図はビツトの後部テー
パー部分が礫を孔壁の地山に押込んで通過すると
きの状態を示す縦断側面図である。第10図は従
来のクローラー用ビツトの正面図、第11図はそ
の側面図、第12図は従来のクローラー用ビツト
により砂礫地盤に削孔している状態を示す縦断側
面図、第13図は従来のクローラー用ビツトの前
端縁部が礫に突き当たつた状態を示す縦断側面
図、第14図は礫が孔内に崩落した状態を示す縦
断側面図、第15図は深い削孔を行なう際にクロ
ーラー用ビツトの前端縁部が礫に突き当たつた状
態を示す縦断側面図、第16図はロツドが撓み変
形すると共に孔が彎曲した状態を示す縦断側面図
である。
図において、1はビツト本体、2は前部テーパ
ー部分、3は後部テーパー部分、4は切削用チツ
プ、5は側面噴気溝、9は礫、10はロツド、1
2はビツト本体摩耗防止用チツプ、14は噴気
孔、15は傾斜送気孔、16は溝である。
1 to 4 show a sand and gravel ground drilling bit according to an embodiment of this invention, in which FIG. 1 is a side view, FIG. 2 is a front view, and FIG. 3 is a second view. FIG. 4 is a sectional view taken along line AA in FIG. 2, and FIG. 4 is a sectional view taken along line BB in FIG. Fig. 5 is a vertical side view showing a state in which a hole is being drilled using the bit of this invention, and Fig. 6 is a longitudinal side view showing a state in which the front edge of the bit of this invention is in contact with gravel. Fig. 7 is a vertical cross-sectional side view showing the state in which the front tapered part of the bit pushes gravel into the ground of the hole wall and passes through it, and Fig. 8 shows the state in which the front tapered part of the bit protrudes from the hole wall when the bit of this invention is pulled out. Fig. 9 is a vertical side view showing the state in which the gravel in the bit hits the rear tapered part of the bit, and Figure 9 is a vertical side view showing the state when the rear taper part of the bit pushes the gravel into the ground of the hole wall. It is. Fig. 10 is a front view of a conventional crawler bit, Fig. 11 is a side view thereof, Fig. 12 is a vertical side view showing a state in which a conventional crawler bit is drilling a hole in gravel ground, and Fig. 13 is a side view of the conventional crawler bit. A vertical side view showing the front edge of a conventional crawler bit hitting gravel, Figure 14 is a vertical side view showing the gravel has collapsed into the hole, and Figure 15 is a deep hole drilling. FIG. 16 is a longitudinal side view showing a state in which the front end of the crawler bit hits gravel, and FIG. 16 is a longitudinal side view showing a state in which the rod is bent and deformed and the hole is curved. In the figure, 1 is the bit body, 2 is the front tapered part, 3 is the rear taper part, 4 is the cutting tip, 5 is the side blow groove, 9 is the gravel, 10 is the rod, 1
2 is a chip for preventing wear of the bit body, 14 is a blowhole, 15 is an inclined air supply hole, and 16 is a groove.
Claims (1)
間部から前端に向かつて縮径する前部テーパー部
分2と中間部から後端に向かつて縮径する後部テ
ーパー部分3とを備え、ビツト本体1の前端部に
半径方向に延長する複数の超硬合金の切削用チツ
プ4が埋込固定され、前記前部テーパー部分2の
側面に、前後方向に延長する側面噴気溝5が設け
られ、前記ビツト本体1には、前部テーパー部分
2の前端中央および側面噴気溝5内に開口する送
気孔が設けられていることを特徴とする砂礫地盤
削孔用ビツト。 A bit body 1 connected to the tip of the rod includes a front tapered part 2 whose diameter decreases from the middle part toward the front end and a rear tapered part 3 whose diameter decreases from the middle part to the rear end. A plurality of cemented carbide cutting chips 4 extending in the radial direction are embedded and fixed in the front end portion of the bit. A sand and gravel ground drilling bit characterized in that the main body 1 is provided with an air supply hole that opens at the center of the front end of the front tapered portion 2 and into the side blowhole groove 5.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP7620486U JPH0316954Y2 (en) | 1986-05-22 | 1986-05-22 |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP7620486U JPH0316954Y2 (en) | 1986-05-22 | 1986-05-22 |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS62190779U JPS62190779U (en) | 1987-12-04 |
JPH0316954Y2 true JPH0316954Y2 (en) | 1991-04-10 |
Family
ID=30923062
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP7620486U Expired JPH0316954Y2 (en) | 1986-05-22 | 1986-05-22 |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0316954Y2 (en) |
-
1986
- 1986-05-22 JP JP7620486U patent/JPH0316954Y2/ja not_active Expired
Also Published As
Publication number | Publication date |
---|---|
JPS62190779U (en) | 1987-12-04 |
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