JP2002250193A - Bit for impact excavation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an economical bit for impact excavation of which only easily abrasive cutting edge can be replaced, and the composition of the cutting edge can be easily changed according to the earth layer at site so that excavation efficiency can be improved. SOLUTION: This invention relates to a bit to be used for a down-the-hole hummer, or a rotary percussion drill to which a bit body, a base body of the bit and a chip made of a hard material having the same shape or a different shape is attached to the front end. It is equipped with a plurality of small diameter bits to be fixed to the excavation face in such a way that they can be freely fixed or removed. At least a small diameter bit comprising of an outer most diameter is fixed to the bit body in such a way that it can be rotated and even rotates round on its own axis according to the rotation of the bit body. A bit body that is arranged to the rotational center axis of the bit body has a feature that it protrudes in the excavation direction against the small diameter bits arranged around its periphery.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bit for impact drilling such as a down-the-hole hammer (hereinafter, referred to as DTH) or a rotary percussion drill (hereinafter, referred to as RPD), and more particularly to an arrangement of cutting blades.

[0002]

2. Description of the Related Art A conventional impact drill bit such as DTH or RPD is an integrated bit in which a chip 4 such as a cylindrical or plate-shaped cemented carbide is directly attached to a bit body 1. 4 and 5. Usually, in the DTH, one hammer is attached to the hammer, but in the case of a large DTH bit having a diameter of about 1 m, a multi-hammer in which a plurality of small-diameter hammers constitute a digging diameter may be used.

FIG. 4A is a side view of a conventional cross-type impact drilling bit (one example for RPD), and FIG. 4B is a plan view of the bit surface. FIG. 5A is a side view of a conventional button-type impact drill bit (one example),
(B) is a plan view of the bit plane. Each of them is an integrated bit in which a chip 4 such as a plate-shaped (FIG. 4) or cylindrical (FIG. 5) cemented carbide is directly implanted in the bit body 1.

[0004]

Such a conventional technique has the following disadvantages. In normal use, the wear of the tip 4 forming the cutting edge is greater than that of the bit body 1,
Since the excavation efficiency decreases, even if the expensive bit body 1 is slightly worn, it must be disposed of, which is uneconomical and has a high environmental load. In addition, the cutting edge of the bit is composed of a large number of inserts, but the outer peripheral insert has a higher peripheral speed and travel distance, so it wears faster, and it must be discarded even when the wear at the center is minimal. Uneconomical and high environmental impact. In addition, the life of the bit increases in proportion to the number of chips on the outermost periphery. However, since the space for implanting the chip is limited, for example, a bit of a drilling diameter φ445 mm class has a limit of about 16 bits. It is difficult to extend the life.

Furthermore, it is necessary to change the shape and arrangement of chips in response to changes in the geological formation during construction on site. In this case, a large-diameter DTH having an excavation diameter of over 400 mm is replaced by a large disassembly facility. Not only is it necessary, but it is also very uneconomical and impractical because several kinds of expensive large bits are prepared and a long-time replacement is required.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems by replacing only the easily worn cutting edge, economical, and easily changing the configuration of the cutting edge according to the on-site stratum. It is another object of the present invention to provide an impact drilling bit configured to enhance drilling efficiency.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a bit used in DTH or RPD, wherein a bit body as a base of the bit and a chip or a chip of the same shape made of a hard material are used. And / or a plurality of small-diameter bits that are detachably mounted on the excavation surface of the bit body so that tips having different shapes are attached to the distal end portion and are located at positions required for excavation. Features.

[0008] At least a small-diameter bit constituting the outermost diameter of the bit is rotatably mounted on the bit body so that each of the bits rotates on the rotation of the bit body. The arranged small diameter bit is mounted so that it cannot rotate.

Further, the small-diameter bit disposed on the rotation center axis of the bit body projects in the excavation direction with respect to the small-diameter bit disposed therearound.

[0010]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a longitudinal sectional view showing an impact drill bit (for DTH) according to an embodiment of the present invention. FIG. 2 (a) is a plan view of a lower bit surface of FIG. 1, and FIG. It is a partial side view of arrow A of a). As shown in FIG. 1 and FIG. 2, an impact excavation bit according to an embodiment of the present invention is a bit used for DTH, and a bit body 1 which is a base of the bit;
The bit body 1 comprises a plurality of small-diameter bits 2 which are removably mounted in a substantially vertical direction on an excavation surface and have tips 4 made of a hard material at the distal end. As shown in FIG. 2A, the small-diameter bit 2 has a plurality of chips each having the same or different cylindrical shape such as a plate-like shape or a cylindrical shape such as an HS or a button. The small-diameter bit 2 which is arranged and implanted and has a different cutting edge shape can be configured in a necessary arrangement so that good excavation efficiency can be obtained.

As shown in FIG. 1, the bit body 1 is spline-coupled to a DTH (not shown) by a spline portion 1b provided on an upper pivot portion, and a lock groove (not shown) provided around an upper end thereof. It is fixed by a fixing member such as a plate. As shown in FIG. 2B, at least on the outermost peripheral side surface of the bit body 1 is a wear resistant treatment 1 such as hard welding or implantation of a wear resistant material tip.
0 is given.

In addition, a small-diameter bit 2b which is an impact excavation bit having an excavation diameter of 200 mm or more and which constitutes at least the outermost diameter of the cutting edge of the plurality of small-diameter bits 2 is:
The bit body 1 is rotatably mounted on the bit body 1 so that each of them rotates on its own axis. As shown in FIG. 1, the rotatable small-diameter bit 2b has a mounting hole 1a drilled in a substantially vertical direction in a lower end surface of the bit body 1.
The small-diameter bit 2b and the bearing member 3 are fixed by a shaft member 8 such as a spring pin, and both rotate integrally. The bearing member 3 is disposed so as to mesh with the rotation guide groove 3a provided horizontally on the outer periphery of the upper end portion thereof, and is fixed to the side surface of the bit body 1 by a bolt 7.
It is rotatably locked (removed) by the pin 6 of the book. A lubricant such as grease is applied around the bearing member 3 such as the space 3b provided on the upper end surface of the bearing member 3 and the rotation guide groove 3a and sealed in the bit body 1. In addition, a seal 9 such as an O-ring is provided on a rotational sliding surface of the lower end of the bearing member 3 with the bit body 1 to prevent foreign matter such as earth and sand from entering.

The small-diameter bit 2a disposed on the rotation center axis of the bit body 1 is screw-connected to a female screw portion 5 provided in the direction of the center axis of the bit body 1, and is mounted so as not to rotate. Further, the small-diameter bit 2a disposed on the rotation center axis is smaller than the small-diameter bit 2b disposed around the rotation center axis.
It protrudes ahead of the downward excavation direction as appropriate. This is because the small-diameter bit 2a at the center portion is always excavated with a small rotational resistance on a new excavation surface, and thereafter the small-diameter bit 2b at the outer peripheral portion can easily be excavated.

In the bit body 1, as shown in FIG.
A fluid flow path 30 is formed along the axial direction of the bit body 1, and a branch flow path 30 a branched from the fluid flow path 30 and bent to extend downward is formed by opening to the excavation surface. ing. The opening of the branch channel 30a provided horizontally on the side surface of the bit body 1 for processing is
Is closed by FIG.
(A), at least two fluid passages 2c are formed to penetrate along the axial direction of the small-diameter bit 2 and communicate with the fluid passage 30 at least in the small-diameter bit 2a of the rotation center axis. ing. Thereby, the fluid flows out to the excavation surfaces of the bit body 1 and the small-diameter bit 2a via the fluid flow path 30, the branch flow path 30a, and the fluid flow path 2c, and cools the excavation surfaces. The lubrication is good.

FIG. 3A is a longitudinal sectional view showing an impact excavation bit (for RPD) according to another embodiment of the present invention, and FIG. 3B is a plan view of a lower bit surface thereof. As shown in FIG. 3A, the bit body 1 is screwed to an RPD (not shown) by a screw portion 1d provided at the upper end of the upper pivot portion. Other configurations are exactly the same as those of the DTH impact excavation bit of FIG. 2 described above, and a detailed description thereof will be omitted.

[0016]

According to the present invention described in detail above,
The following excellent effects are provided. (1) The bit body can be used a plurality of times for a long period of time by exchanging the small-diameter bit, and a small-diameter bit mass-produced can be used. For this reason, the cost of reproducing the bit is extremely low, and the excavation performance after the reproduction can be maintained at the high performance state at the time of new production, so that the economic effect is extremely high.

(2) Since the small-diameter bit constituting at least the outermost diameter of the cutting edge of the bit rotates by the rotation (revolution) of the bit body, the position where the chip is implanted with respect to the excavation surface is not fixed. Since the chips are worn evenly, the resources can be consumed evenly and the resource value can be sufficiently consumed, and if the number of chips is equal to that of the conventional bits, the effect of extending the life is great. (3) Since the small-diameter bit located at the outermost periphery is rotatable, the number of outermost excavated chips can be regarded as the sum of the outermost chips of the outermost small-diameter bit. For example,
8 in the bit according to the present invention of the drilling diameter φ445mm class
X 4 = 32, whereas conventional bits have 16
The life is about twice as long as the conventional one.

(4) Since the exchange of small diameter bits can be easily performed in a short time with a tool such as a standard wrench, change of the optimum cutting edge type in accordance with the bit wear at the construction site, changes in the formation and the geology. Such measures can be easily taken, high excavation efficiency can be obtained, and it is economical.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an impact excavation bit (for DTH) according to an embodiment of the present invention.

FIG. 2A is a plan view of a lower bit surface of FIG. 1;
(B) is a partial side view as viewed in the direction of arrow A in (a).

FIG. 3A is a longitudinal sectional view showing an impact drill bit (for RPD) according to another embodiment of the present invention, and FIG.
Is a plan view of the lower bit surface.

FIG. 4A is a side view of an example of a conventional cross-type impact drilling small-diameter bit (for RPD), and FIG. 4B is a plan view of a lower bit surface thereof.

FIG. 5A is a side view of an example of a conventional button-type impact digging bit, and FIG. 5B is a plan view of a lower bit surface thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bit body 1a Mounting hole 2 Small diameter bit 2a Small diameter bit of rotation center axis 2b Small diameter bit around (or outer circumference) 3 Bearing member 3a Rotation guide groove 3b Space 4 Chip (blade tip) 5 Screw 6 Pin 7 Bolt 8 (Spring Shaft member (such as pin) 9 Seal (such as O-ring) 10 Wear-resistant treatment 30 Fluid flow path 30a Branch flow path 31 Plug

Claims (3)

[Claims] 1. A bit used for a down-the-hole hammer or a rotary percussion drill, wherein a bit body as a base of the bit and a tip of a same shape made of a hard material and / or a tip having a different shape are attached to a tip portion. And a plurality of small-diameter bits removably mounted on the excavation surface of the bit body so as to be located at a position required for excavation. 2. A small-diameter bit constituting at least the outermost diameter of the bit is rotatably mounted on the bit body so that each bit rotates on the rotation of the bit body. The impact excavation bit according to claim 1, wherein the arranged small-diameter bit is mounted so as not to rotate. 3. The small-diameter bit arranged on the rotation center axis of the bit body projects in the excavation direction with respect to the small-diameter bit arranged around the small-diameter bit. The impact drill bit as described.