JPS60129390A - Drill bit for core boring - 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 [Field of Application of the Invention] The present invention relates to an improvement in a core boring drill bit used for excavating rock.

[Background of the invention]

Traditionally, when conducting geological excavation, core boring is performed to collect the core of the stratum, but this method involves rotating a drill bit attached to the tip of a boring rod, and drilling with a cutting edge formed at the tip. ing. In such a drill bit, the cutting edge wears out after digging a certain distance and reaches the end of its life, so the boring rod is pulled up and removed each time, and the worn bit is replaced with a new bit.

However, in the past, the boring rod had to be pulled up every time the bit was replaced, which wasted time raising and lowering the rod.In particular, as the depth of excavation increased, wasted consumption time increased. For this reason, bit structures that can be converted at the bottom of the hole without having to pull up the rond have been proposed, but these are mechanically complex or have structures unsuitable for core boring9, making them impractical. Ta.

[Purpose of the invention]

The present invention focuses on the above-mentioned conventional problems, and provides a bit with a multilayer structure that allows the bit to be replaced at the bottom of the hole without pulling up the iron, and has a core that can significantly increase the life of the cutting edge, especially on the outer layer side. The purpose is to provide boring drill bits.

[Summary of the invention]

In order to achieve the above object, a core boring drill bit according to the present invention includes a cylindrical bit body having a bit head provided with a cutting edge at the tip, and a tip outer surface along the circumferential direction of the bit head. A divided bit having outer layer cutting blades which are attached in an overlapping manner and are divided into a plurality of parts and each having a cutting edge area substantially equal to the cutting edge area of the bit body, and the outer layer of the divided bits is arranged every other piece. A set of cutting blades is connected with each leg to a separate ring mounted inside the bit body, and the reduced diameter outer diameter dimension of the outer layer cutting blade of each set of the split bit removed from the bit body is inserted into the bit body. It should be as large as possible.

With the above configuration, when the cutting edge of the outer bit head becomes worn, it can be removed from the inner bit head, reduced in diameter, and pulled upward through the hole in the bit body. In this case, the bit head on the outer layer side is composed of a plurality of outer layer cutting blades, but instead of having a structure that reduces the diameter uniformly in one piece, the outer layer cutting blades arranged every other bit are separated into one set. Since the bit body is removed by following the hole in the bit body, the effective area of each cutting edge can be increased accordingly, and by making it equal to the cutting edge area on the bit body side, @5
Ru. As a result, the outer layer bit head has four holes that are not auxiliary but are equivalent to the cutting edge on the bit body side, and the overall digging distance is increased by 11d, thereby increasing work efficiency.

[Embodiments of the invention]

Embodiments of the core boring drill bit according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a 9+11 plane view of the main part of the drill bit of the embodiment, and this drill bit includes a cylindrical bit body 10 that is attached to a boring rod, and a cylindrical bit body 10 that is attached to a boring rod.
The split bit head 12 is attached to the outer layer of the bit head.
The main structure is

First, the bit body 10 has a bit head 16 in which a diamond 14 is embedded in the tip on the digging side, as shown in detail at h4''1 in FIG. The bit head 16 has several water grooves 18 continuously formed on the inner and outer surfaces, and in particular, in the embodiment, there are eight water grooves 18 equally spaced along the direction of the circle 7N. #
18, eight cutting edges 20 are formed. Two rows of annular protrusions 22 and 24 are formed on the inner peripheral surface of the central part of the bit body 10 in order to fix the split pit head 12, which will be described later. There are kite grooves 26 at intervals of a number l equal to the water burial 18, and the other protrusions 24 have water grooves 18 at every other groove.
Half of the guide grooves 28 corresponding to the number of guide grooves 28 are formed. Then, between the two defects 22 and 24, and the proximal protrusion 24
The guide 7426.2 is provided on the inner circumferential surface of the proximal side 1d of the guide 7426.2.
One protrusion 30.32 parallel to 8 is provided, and this recess 30.32 is used to hold the divided bit head 12 in a fixed position. Note that a screw 34 for attachment to a boring rod is formed on the inner surface of the proximal end of the bit body 10.

Next, on the outer surface of the tip of the pit head 16 of the bit body 10, a divided pit head 12 composed of an outer cutting edge 36 divided into a plurality of parts is attached. Diamonds 38 are embedded in the surface of each outer cutting edge 36 of this split bit head 12, and the water groove 1 on the bit body 10 side described above is
It is formed so as to have the same cutting edge area as each cutting edge 20 divided by 8, and is mounted on a crown. Therefore, a groove 40 having a width equal to the water groove 18 is formed between adjacent outer layer cutting edges 36 of the split bit head 12, and the groove 40 functions as a water groove. Each of the outer layer cutting blades 36 is provided with a fitting protrusion 42 on its inner surface, and this protrusion 42 is connected to the water groove 1.
The shape is compatible with 8. And when installing,
Fitting the fitting protrusion 42 into the water groove 18 for positioning;
It is attached to the outer surface of the tip of the pit body 10 so as to straddle the adjacent cutting edges 20 . In this case, the outer layer cutting edge 36
The back surface of the bit body 10 has a shape that is a transfer of the outer surface shape of the cutting blade 18 of the corresponding bit body 10, which provides stability during installation and inner cutting edge 36 during operation. This is to prevent the cutting blade 20 on the i side from being misaligned. This transfer may be manufactured by sintering powdered metal using a mold equal to the cutting edge 20 of the inner layer.

In order to fix and hold the above-mentioned outer layer cutting blade 36 in a fixed position,
In the embodiment, the eight outer layer cutting blades 36 are fixed as a set of four pieces arranged at every other edge. Therefore, an outer layer cutting blade 36B constituting one second divided bit head 12B is arranged between each outer layer cutting blade 36A of the first divided bit head 12A constituting one set (see FIG. 3).

Furthermore, each set of outer layer cutting blades 36A, 36B is configured to operate independently. That is, as shown in FIG. 1, a long leg 44A and a short leg 44B are connected to each of the outer no-cutting blades 36A and 36B on the inner surface side of the bit body 10 in succession to the fitting protrusion 42. 44A,
44B is a ring 46 along the inner peripheral surface of the bit body 10.
A and 46B, respectively. As shown in FIG. 5, the ring 46B is an annular band plate, and is formed as an elastic piece with a cut 48 formed in a part thereof so that the diameter can be changed. Then, the cut 48 of the ring 46B is opened to expand the diameter, and the rings 46B are opened at both ends. The bit body 10 is assembled by sandwiching the protrusions 30 provided on the inner surface between the annular protrusions 22 and 24 on the inner surface of the bit body 10 from both sides.
It is designed to be placed along the inner circumferential surface of the At this time, the leg 44B connected to the ring 46B
The outer cutting edge 36B is placed in a lower layer in the guide groove 26 formed in the outer layer for positioning in the circumferential direction, and comes into contact with the edge of the ring 46B and the annular protrusion 22 to prevent the outer cutting edge 36B from falling off. Further, the other ring 46A has a similar structure, and is arranged with a phase shift of only half the pitch of the leg 44B with respect to the ring 46B on the distal end side. In this case, the legs 44A connecting the ring 46A and the outer cutting edge 36A are fitted into corresponding guide grooves 26.28 provided in each of the two rows of protrusions 22.24. The legs 44A, 44B connecting the outer cutting edges 46A, 46B and the rings 46A, 46B are given elasticity so as to position the outer cutting edge 36 in the direction of the central axis of the bit body 10. Therefore, when the outer layer cutting edge 36 is removed from the bit body 10, each set of outer layer cutting edges 36A, 36B converges in the central axis direction, and as shown in FIG. 36B) is converged so that the circumscribed circle is less than or equal to the inner diameter of the bit body 1o, so that the bit body 10 can be inserted into the bit body 10. As a result, split bit head 1
2 is removed from the bit head 16 of the bit body 10,
Each set can be removed separately through the bit body lo.

Rock excavation is carried out by attaching the split bit head 12 in a superposed state to the bit head 16 of the bit body 10, but when the cutting edge 36 of the outer layer wears out, the split bit head 12
A release mechanism 50 is provided within the bit body 10 in order to remove the bit body 10 from the bit body 10. This release mechanism 50
is formed of an annular plate 52 along the inner peripheral surface of the bit body 10 and a wedge 54 protruding from the edge of the annular plate 52 facing the bit head 16. The wedges 54 are protruded in the same number (4 wedges) as the guide grooves 28 at positions that are vertically aligned with the guide grooves 28 provided on the annular protrusion 24 on the proximal end side of the bit body 10, and their tips are connected to the inner wall of the bit body 1o on one side. ring 46A
It is possible to infiltrate between the outer surface of the Therefore, by pressing the rear end edge of the annular plate 52, the shift rust 54 acts on the mass ring 46A, releases it from the gripping state of the protrusion 32 and makes it nervous, and the corresponding outer layer cutting edge 36
It can be removed by removing A. When the wedge 54 is continued to advance, it slides within the guide groove 28 and the next stage ring 46B can be released in the same way.

Next, a recovery machine #56 that removes the divided bit head 12 including the outer layer cutting edge 36 from the bit body 10 and raises it to the ground can be installed.

The recovery mechanism 56 is shown in FIGS. 7-8. Jin collection machine 41 (t
56 hangs down toward the bottom of the hole inside the Y-opening polling rod 58 shown in the figure, and uses its own weight to operate the release mechanism 50 to release the divided bit head 12 on the outer layer side into the bit body 1.
It is removed from zero and collected on the ground. That is, the recovery mechanism 56 has a recovery jig main body 6O that is suspended within the Pauline Blond 58, and one end side of a pair of arm members is pivotally attached to this body, and the ends of the recovery jig body 6O are shaped like open legs and have their tips oriented laterally. After attaching the protruding latch part 62, the latch part 62
The edge of the annular plate 520 is pressed when hanging down. Further, a recovery jig groove 64 with a small diameter is formed on the distal end side of the recovery jig main body 60 so that the rings 46A and 46B can be held therein, followed by a tapered surface 66 which is successively tapered. A conical head 68 is formed at the tip. Therefore, when the collection jig main body 60 is hung down, the latch portion 62 presses against the annular plate 52 and the first JR
Release the eye ring 46A, remove the first stage divided bit 12A on the outer layer side from the bit body 10 as shown in FIG. It is sufficient to pull it upward in the form shown in the figure. Note that when releasing the first stage ring 46A, use the wedge 54.
A stopper ring 70 is attached in the middle of the Pauline blond 58 so that the second stage ring 46B will not be released at the same time when the position of the stopper ring 70 is reached. This stopper ring 70 is connected to the collection jig base 7 connected to the collection jig main body 60.
2 is supported, and further advancement of the recovery jig base 60 is prevented in the supported state.

After releasing the first stage ring, the divided outer layer bit is immediately collected, and then a collection jig body similar in shape to the one described above but different in length from the first collection jig body is attached and inserted into the boring rod. By hanging down, the latch part pushes the annular plate further and releases the second stage ring.

Further, the stopper ring is provided so as not to break the bit body, and the length of the recovery jig body is adjusted during the second and second recovery.

The core boring drill bit having such a configuration operates as follows. First, in order to assemble the outer layer side split bit head 12 into the bit body 10, insert the second split bit head 12B from the base end opening of the bit body, and insert the four outer layer cutting blades 36B into the bit head 16 on the main body side. The ring 46B is opened and the protrusion 30 is held between the rings 46B and 46B. Subsequently, the second divided bit head 12A is attached in the same manner, and the assembled bit body 10 is screwed onto the Pauline blond 58. Set to a position where the wedge 54 of the release mechanism 5o does not act.

Excavation is performed using such a drill bit, and in this case, the outer layer cutting edge 36 acts in advance to perform the excavation. During this excavation, a groove 40 equivalent to a water groove between the plurality of divided outer layer cutting blades 36
Since the cutting edge area of the outer layer cutting edge 36 is determined to be the same as that of the bit body side, it has the same dimensions as the water groove 18. As a result, the cooling function can be improved to the same level as the bit body 10. After that, the outer layer cutting blade 36 excavates to a certain depth and wears out.
A core tube (not shown) is used to remove the outer cutting edge 36.
is pulled up and the collection mechanism 56 is lowered into the Pauline Blond 58. By lowering this recovery mechanism 56, the latch portion 6
2 hits the current plate 52 of the WF removal mechanism 50, the wedge 54 first releases the first stage ring 46A't-protrusion 32, and the ring 46A is installed in the recovery jig groove 64. Thereafter, the wedge 54 reaches a position close to the second stage ring 46B and is prevented from further advancing by the stopper ring 20.

During this time, the recovery jig main body 60 is attached to the first divided pit head 12.
As it moves slightly along with A, the outer layer cutting blade 36A comes off from the bit body 10, and the four outer layer cutting blades 36A detach from the leg 44A.
As shown in FIG. 6, it converges at the tip of the recovery jig main body '60 due to the elastic action of the recovery jig body '60. Then, the first divided pit head 12A is pulled up to the ground together with the recovery jig main body 60. Thereafter, the second divided bit head 12B including the remaining four outer layer cutting edges 36B is recovered by the second hanging of the recovery jig.

According to this embodiment, since the outer layer split bit head 12 attached to the bit body 10 in a superposed state is removed and recovered in two stages, the cutting edge of the split bit head 12 The area can be increased to an area equal to the cutting edge area of the bit body 10. That is,
The life of the cutting edge depends on the area of the cutting edge, which is the exclusive area of the part where the diamond grains are planted, but if the outer layer cutting edge 36 is divided and removed and recovered in one step,
The cutting edge area of the outer layer cutting edge 36 is approximately 6 times larger than that of the e-t main body 10.
This can only be achieved by 4%, which makes it impossible to increase the life of the outer no-cutting blade 36. However, according to this embodiment, 2
Since it has a staged recovery structure, recovery can be made even if the effective cutting edge area of each divided outer layer cutting edge 36 is increased, and one bit body 1
It can be increased to about 96% of that of o, making it possible to significantly extend the life.

Also, the split bit head 1 superimposed on the bit body 10
Since the inner surface of 2 has a shape that copies the cutting edge shape of the bit body 1o, it is possible to prevent damage to the diamond 14 on the bit body 10 side during actual excavation, and to stabilize the state of 1 when working. It can be performed.

〔Effect of the invention〕

As explained above, according to the present invention, the cutting edge area of the outer layer bit head is increased, and the life of the inner and outer bits is made equal, thereby increasing the overall life of the drill bit. ;・ can be obtained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional side view of a main part of a drill bit according to an embodiment;
Figure 2 is a sectional view of the bit body, Figure 3 is a diagram of the split bit head arrangement of the drill bit, and Figure 4 is IV-1V of Figure 3.
Figure 5 is a perspective view of the ring, Figure 6 is a removed layout of the first split bit head, Figure 7 is a partial sectional view of the boring rod showing the recovery device, and Figures 8 and 8 are a perspective view of the ring. FIG. 3 is a partial cross-sectional view of the bit head in a removed state. 10...Bit body, 12...Divided bit head,
16... Bit head, 20... Cutting blade, 26.28
... Guide groove, 36 ... Outer layer cutting edge, 44A, 44B
...Leg, 46AJ46B...Ring, 50...Release mechanism, 54...Wedge, 5'6...Recovery mechanism, 5
8... Boring rod. Figure 1 Figure 2 Figure 3 Figure 4 SQ Figure 5 Figure 6 Figure 7 Figure 8

Claims (2)

[Claims] (1) A rectangular cylindrical bit body having a bit head with a cutting edge at the tip, which overlaps and is attached to the outer surface of the tip along the circumferential direction of the pit head, and is approximately equal to the cutting edge of the pit body. a split bit having an outer layer cutting blade divided into a plurality of parts having a cutting edge area, and the valve opening bit is a separate bit that is installed in the bit body with a set of outer layer cutting blades arranged every other piece. The core is characterized in that the diameter of the outer layer cutting blade of each set of the split bit, which is connected to the ring with each leg and the pit body or the stone plate is removed, is such that the outer diameter dimension is such that it can be inserted into the bit body. Drill bit for boring. (2) The drill bit for core boring according to claim 1, wherein the inner surface of the split bit is formed in a shape that is a transcription of the outer surface of the cutting edge of the pit body.