JPS6238516B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a trench bit for forming a groove toward a fracture boundary line in a charge hole drilled in rock.

Generally, when excavating tunnels, gunpowder is loaded into a charge hole drilled with a rock drill and detonated, but this explosive force acts equally on the entire circumference of the charge hole. As shown in Fig. 11, it is not always possible to obtain a fracture line along the fracture boundary line a in the nominal charge hole b located on the fracture boundary line a of the tunnel, but it is possible to obtain a fracture line that forms a large angle with the fracture boundary line a. There is a problem that cracks occur in the rock.

For this reason, conventionally, for the charging hole b located at the crushing boundary line a, a high-pressure water injection nozzle equipped with a pair of injection ports oriented 180 degrees apart from each other has been used, for example, as described in Japanese Utility Model Application No. 119404/1983. By forming a groove c along the fracture boundary line a in the charge hole b using a drilling machine such as A substantially approximate fracture line is obtained.

However, the fracture boundary line a of the tunnel is usually
Although the curve is close to a circle, if grooves c are formed in different directions at 180 degrees, the actual fracture line will be a polygon that circumscribes the planned fracture boundary line a, so extra cement will be added after blasting. Even if it is necessary to fill the tunnel with concrete and there is only a slight error between the planned fracture boundary line a and the actual fracture line, a large amount of cement concrete will have to be wasted if one long tunnel is dug. The current situation is that there is no such thing.

In addition, when excavating a tunnel, hexagonal or square-shaped fracture boundaries d and e are placed inside the fracture boundary line a, as shown in FIG. 12 or 13.
A method has also been adopted in which holes are drilled, conductive holes, etc., and the holes are enlarged step by step.However, in the conventional drilling machine, the hole b is crushed into the charging hole b at each apex of a hexagonal or square shape. It was difficult to form grooves f and g along boundary lines d and e.

In view of this, the present invention consists of a front part structure, an intermediate part structure, and a rear part structure that can be divided in the axial direction. A groove digging tip is provided to protrude outward in the radial direction, and the intermediate structure and the front or rear structure are engaged with each other so that the angle between the two tips can be changed. The present invention provides a trench bit that can be set at an appropriate angle toward the fracture boundary line to dig a trench, thereby solving the problems of the conventional art.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below based on embodiments with reference to the drawings.

<Example 1> This example is shown in FIGS. 1 to 4, in which 1 is a drilling bit, and the bit body 2 has a front structure 3, an intermediate structure 4, and a rear structure that can be divided in the axial direction. body 5
Grooving chips 6 and 7 are provided on the front structure 3 and the intermediate structure 4, respectively, protruding outward in the radial direction. The angle can be changed.

The front, middle and rear structures 3, 4, 5 are
They have the same diameter and are formed to be slightly smaller than the charging hole 80 drilled in the bedrock 79. The intermediate structure 4 has a cylindrical shape. A screw hole 10 is opened in the front structure 3 in the axial direction from the rear end.
has a shaft portion 11 protruding from its front end, and the shaft portion 11 passes through the intermediate structure 4 and is screwed into the screw hole 10 of the front structure 3.
and the intermediate structure 4 are engaged with each other by engagement means 12 .

The engagement means 12 is composed of engagement teeth 13 and 14 formed in a concave and convex shape with the same pitch in the circumferential direction on the mating surfaces of the front structure 3 and the intermediate structure 4, respectively.
By displacing the meshing position of both engaging teeth 13, 14 in the circumferential direction, the angle formed by the groove digging tips 6, 7 of each of the front structure 3 and the intermediate structure 4 can be changed. .

The trench digging chips 6 and 7 are each made of three button-shaped chip pieces 6a to 6c and 7a to 7c.
It consists of a group of Each chip piece 6a to 6c and 7a
7c are press-fitted into the fitting holes 9 formed at intervals in the axial direction on the outer periphery of the front structure 3 and the intermediate structure 4, respectively, in one row and axially rearward. It is provided so that the height gradually increases as one goes towards the top. Each of these chip pieces 6a
~6c and 7a~7c are preferably made of cemented carbide.

Note that the rear structure 5 is provided with a screw hole 15 in the axial direction from the rear end, and the rear structure 5 is screwed into a threaded portion provided at the tip of a rock drill rod (not shown). As a result, the drilling bit 1 is fixed to the rod. Further, the shaft portion 11 is provided with a high-pressure water supply hole 16 having one end opened in the screw hole 15 and the other end opened in the front end surface of the shaft portion, and a shallow and shallow water supply hole 16 is provided on the outer peripheral portion of the shaft portion into which the intermediate structure 4 is fitted. A wide groove 17 is formed, and the high pressure water supply hole 16 and the groove 17 are connected to the communication path 1.
It is communicated at 8.

Furthermore, one end of the front structure 3 is provided with a screw hole 10.
A high-pressure water injection hole 19 is provided at the other end of the groove-drilling tip 6 just before the frontmost tip piece 6a. This connection allows communication with the high-pressure water supply hole 16. Further, the intermediate structure 4 is provided with a high-pressure water injection hole 20 that penetrates the structure wall inside and outside at an intermediate position between each of the chip pieces 7a to 7c. 1
1 so as to communicate with the groove 17.

When using the above-mentioned trench bit 1, first, the front structure 3 and the intermediate structure 4 are aligned so that the trench drilling tips 6 and 7 correspond to the direction of the crushing boundary line in the charging hole 80. The two structures 3 and 4 are fixed to the shaft portion 11 of the rear structure 5 by adjusting the angle and engaging with each other. When the drilling bit 1 is fixed to the rod of a rock drill and moved forward while repeating the striking motion, a pair of grooves toward the fracture boundary line are formed in the hole wall of the charging hole 80 for each of the chip pieces 6a to 6c. 7a~
7c, the hole is dug deeper in stages. When trenching, the cuttings adhering to each of the chip pieces 6a to 6c and 7a to 7c are discharged by high pressure water injected from high pressure water injection holes 19 and 20.

In this example, the engagement teeth 13 and 14 as engagement means are provided on the mating surfaces of the front structure 3 and the intermediate structure 4, but If the screw end position of is always constant,
The engagement teeth can also be provided on the mating surface between the rear end surface of the intermediate structure 4 and the rear structure 5 to serve as an engagement means. Regarding the formation of these engaging teeth on the mating surfaces of the intermediate and rear structures 4 and 5, the coil spring of Example 2 described later is interposed between the front structure and the intermediate structure. It can also be applied to groove bits.

Embodiment 2 This embodiment is shown in FIGS. 5 to 8, and relates to a trench bit 21 in which the engaging means for changing the angle of the trench drilling tip is different from that of the first embodiment.

That is, the intermediate structure 24 of the bit body 22
is formed into a cylindrical shape with a hexagonal shape 28, while the shaft portion 31 of the rear structure 25 has a range l of its base end portion.
is formed in a hexagonal part 29 with a hexagonal cross section corresponding to the hexagonal hole 28, and a circular part 33 and a threaded part at the tip are connected to the hexagonal part 29, and the hexagonal hole 28 and the hexagonal part 29 are engaged with each other. A combining means 32 is configured.

The front structure 23 is attached to the rear structure 25 by screwing the threaded portion of the shaft 31 into the screw hole 30 formed in the same manner as in Example 1 until the bottom of the screw hole abuts the tip end surface of the shaft. fixed against, and
The intermediate structure 24 is biased toward the rear structure by a coil spring 34 inserted through the shaft 31 between the intermediate structure 24 and the front structure 23 .

The angles formed by the groove digging tips 26 and 27 provided on the front structure 23 and the intermediate structure 24, respectively, can be changed by moving the intermediate structure 24 into the coil spring 34.
By moving forward against the force, the intermediate structure 24 and the rear structure 25 are disengaged, and the intermediate structure 24 is rotated by a predetermined angle and the rear structure 25 is moved again. This can be done by engaging the

Note that the groove digging tips 26 and 27 are composed of three pieces of tips 26a to 26c and 27a to 27c, respectively, as in the first embodiment, and each of the tips 26a to 26c and 27a to 27c has a fitting hole. 3
It is attached to 7. Further, in FIG. 5, 35 is a screw hole, 36 is a high-pressure water supply hole, and 39 is a high-pressure water injection hole.

Incidentally, when trenching, the intermediate structure 24 is always pressed against the rear structure, so the engagement between the hexagonal hole 28 and the hexagonal part 29 is never released.
The groove digging tips 26 and 27 maintain the set angle.

Further, in this example, the engaging means 32 is formed of the hexagonal hole 28 and the hexagonal part 29, but it may be formed into other polygonal shapes such as a pentagonal shape or an octagonal shape.

<Example 3> This example is shown in FIG. 9, and is an example in which the tips 46 and 47 of the drilling bit 41 are different from those of Examples 1 and 2.

That is, the trench digging tips 46, 47 of this example
The bit has a rectangular plate shape with a cutting blade formed on the front edge and the upper edge, and the back and bottom surfaces are respectively the front structure 43 or the intermediate structure 44 of the bit body 42.
Mounting seats 54 on the front surfaces of the supporting parts 50, 51 provided in the outer circumferential axial direction and on the outer circumferential surfaces of both structures 43, 44,
55 by silver brazing. Also, just before the chips 46 and 47, there is a high pressure water supply hole 5.
High-pressure water injection holes 57 and 58 communicating with 6 are open. Other structures such as the rear structure 45 and the engagement means 52 are the same as in the first embodiment.

Note that the trench digging tips 46 and 47 of this example are as follows:
The same can be applied to the drilling bit 21 of the second embodiment.

<Embodiment 4> This embodiment is shown in FIG. 10, and is an example in which the tips 66 and 67 of the trench bit 61 are different from those of the previous embodiments.

That is, the groove digging tips 66 and 67 are rectangular plate-shaped with a digging blade formed on the upper edge, and have mounting holes formed in the front structure 63 and the intermediate structure 64 of the bit body 62 in the axial direction, respectively. The cutting blade is fitted into the groove and fixed by silver brazing or the like, and the height of the cutting blade gradually increases as it moves rearward in the axial direction. Also, trench digging chips 66, 67
High-pressure water injection holes 77 and 78 communicating with the high-pressure water supply hole 76 are opened immediately in front of the high-pressure water supply hole 76 . Rear structure 6
5. Other structures such as the engaging means 72 are the same as in the first embodiment.

It goes without saying that the groove drilling tips 66 and 67 of this embodiment can also be applied to the groove drilling bit 21 of the second embodiment.

As described above, according to the present invention, the intermediate structure is engaged with the front structure or the rear structure by the engagement means, and the angle formed by the pair of trenching tips can be changed. This makes it possible to form a crushing groove facing the appropriate direction by changing the angle of the chip each time according to the shape of the crushing boundary line, improving work efficiency when excavating tunnels, and improving the shoring and lining becomes easier.

[Brief explanation of the drawing]

1 to 10 illustrate embodiments of the present invention, FIG. 1 is a partially sectional plan view showing a drilling bit of Example 1, and FIG. 2 is an A-A in FIG. 1. Line sectional view, Figure 3 is a BB line sectional view of Figure 1, Figure 4
The figure is a sectional view taken along the line CC in Figure 1, and Figure 5 is Example 2.
Figure 6 is similar to Figure 1 in Figure 5.
-D cross-sectional view, Figure 7 is a cross-sectional view taken along line E--E in Figure 5, Figure 8 is a cross-sectional view taken along line F--F in Figure 5, and Figure 9 shows the essentials of the drilling bit of Example 3. A plan view showing the part;
FIG. 10 is a diagram similar to FIG. 9 in Example 4,
FIGS. 11 to 13 are diagrams showing the arrangement of charging holes on the fracture boundary line, respectively. 1, 21, 41, 61...Drilling bit,
2, 22, 42, 62... Bit body, 3, 2
3, 43, 63...Front structure, 4, 24, 4
4, 64... intermediate structure, 5, 25, 45, 6
5... Rear structure, 6, 26, 46, 66... Chip, 7, 27, 47, 67... Chip, 12,
32, 52, 72... engaging means, 13, 14...
Engaging tooth, 28...hexagonal hole, 29...hexagonal part.

Claims (1)

[Scope of Claims] 1. A groove is formed in a charging hole drilled in rock toward a fracture boundary line, and the bit body that can be inserted into the charging hole has a front structure that can be divided in the axial direction. ,
Consisting of an intermediate structure and a rear structure, the intermediate structure is cylindrical, and is inserted into either the front structure or the rear structure by penetrating the intermediate structure and fitting into the other. a shaft portion, the front structure and the rear structure are fixed to the shaft portion, and groove digging chips are provided on the front structure and the intermediate structure, respectively, protruding outward in a radial direction; A drilling bit characterized in that the intermediate part structure and the front part structure or the rear part structure are engaged with each other by means of an engaging means so that the angle of the tips seen from the axial direction can be changed. 2. The engaging groove according to claim 1, wherein the engaging means is constituted by engaging teeth formed in a concave and convex shape in the circumferential direction on the mating surfaces of the front structure and the intermediate structure, respectively. Bits for use. 3. The engaging means is such that the shaft of the front structure or the rear structure and the hole of the intermediate structure have the same polygonal cross-section, and the shaft and the hole fit together. The drilling bit described in item 1.