JP2003278473A - Excavating tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an excavating tool preventing a center member 9 from being easily dropped out during the excavation to easily separate it from a tool body 1 after the completion of excavation. <P>SOLUTION: The center member 9 is inserted from the front end side and is mounted on the inner circumference 6 of the front end of the cylindrical tool body 1 in a detachable manner, and a circular elastic member 10 elastically deformable in the direction of a diameter is provided between the inner circumferential surface of the front end of the tool body 1 and the outer circumferential surface of the center member 9 opposed thereto along the circumferential direction of the inner and outer circumferential surfaces. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a center member removably mounted on the inner periphery of the tip of a cylindrical tool body, and excavates while the center member is mounted during excavation.
After the end of excavation, the present invention relates to an excavating tool for projecting and dropping a center member by a rod inserted from the rear end side of a tool body, and pulling out only the tool body from a drilled hole.

[0002]

2. Description of the Related Art As an excavating tool of this type, the inventors of the present invention have disclosed, for example, in Japanese Unexamined Patent Publication No. 7-217356, a bit main body (tool main body) which is cylindrical and has a blade portion on the outer peripheral portion of the tip surface. A taper surface whose inner diameter is gradually reduced at a constant angle in the base end direction is formed on the inner peripheral surface of the tip end part of the bit body, and a cylindrical shape is formed on the inner end part of the tip part of the bit body at the base end part of the bit body. It has been proposed that a center bit (center member) having a tapered surface that comes into contact with the tapered surface is fitted from the tip end side, and these tapered surfaces are brought into close contact with each other so as to be detachably supported. Further, as an anchoring method using such an excavating tool, the bit body is attached to the tip of the driving force transmitting means such as a cylindrical rod to perform excavation, and after the excavation is completed, the anchor is placed in the driving force transmitting means. There is also proposed a method of inserting and pressing the center bit to separate it from the bit main body, and pulling out the driving force transmitting means and the bit main body from the excavation hole and collecting them. Therefore, according to such an excavating tool and anchor construction method, the bit body is disposable by pulling out the driving force transmitting means and the bit body while filling the excavation hole with cement milk or the like through the inside of the driving force transmitting means. It is possible to perform efficient anchor construction without

[0003]

However, in the above-described drilling tool, since the center bit is attached to the bit body by the frictional force due to the close contact between the tapered surfaces as described above, one of these tapered surfaces is used. However, if there is a molding error or the like, the two tapered surfaces may not surely come into close contact with each other, and the center bit may drop during excavation. On the other hand, when excavating, since the excavating load acts on the center bit in the direction of the base end where the tapered surface is gradually reduced in diameter, both the tapered surfaces are too precisely formed so that they can adhere to each other over the entire surface. When the center bit is pushed into the inner circumference of the bit body by the excavation load as if pushing a wedge, the center bit is firmly held by the bit body due to the frictional force acting on the entire surfaces of the taper surfaces that are in close contact, and the excavation ends. There is also a problem that when the anchor is inserted later and the center bit is pressed, the center bit cannot be separated from the bit body unless it is pressed with a strong force.

The present invention has been made under such a background, and in the above-described drilling tool, the member such as the center bit is not easily dropped off during the drilling, however, the drilling is completed. The aim is later to provide a drilling tool which can be easily separated from the body.

[0005]

In order to solve the above-mentioned problems and to achieve such an object, the present invention inserts a center member into the inner circumference of the tip of a tool body having a tubular shape from the tip side. Detachably attached, an annular elastic member elastically deformable in the radial direction between the inner peripheral surface of the tool body tip and the outer peripheral surface of the center member facing the inner peripheral surface of the inner peripheral surface of the tool. It is characterized by being inserted along. Therefore, in the excavating tool having such a configuration, the elastic force of the elastic member during excavation can securely hold the center member on the inner circumference of the tool body to prevent the center member from falling off. By pressing the center member with a force sufficient to resist it, it is possible to easily separate and remove from the tool body.

Further, the inner peripheral surface of the tip end portion of the tool body and the outer peripheral surface of the center member are provided with a mounting groove into which the elastic member is inserted and the elasticity of the elastic member inserted into the mounting groove. The bottom surface of the groove is formed so as to face each other with a pressing groove, and on the bottom surface of the pressing groove, when the pressing groove is on the tool body side, the tip side of the tool body approaches the tip side. A center member is formed by forming an inclined surface toward the inner peripheral side and, if the pressing groove is on the center member side, an inclined surface toward the outer peripheral side toward the rear end side of the tool body. When pressing from the rear end side (base end side) when separating, the elastic member pressing the groove bottom surface of the pressing groove elastically deforms in the direction opposite to the pressing direction so as to be guided by this inclined surface. , The center part from such a tool body It can be a separate more surely and easily.

On the other hand, if at least a part of the inner peripheral surface of the tip end portion of the tool body and the outer peripheral surface of the center member are formed in a polygonal cross-section capable of fitting with each other, excavation is performed while rotating the tool body. In this case, the fitted portion can transmit the rotational force to the center member, and the center member can also be provided with a blade to enable excavation. In addition, if at least a part of the inner peripheral surface of the tool body tip portion and the outer peripheral surface of the center member are formed with taper portions that can be intimately contact with each other and gradually increase in diameter toward the tip end side, the elastic force of the elastic member is generated. Together with the holding, the center member can be more reliably prevented from falling off during excavation.

Further, a plurality of elastic members are provided between the inner peripheral surface of the tool body tip and the outer peripheral surface of the center member.
If the tool main body is interposed so as to be aligned in the front-rear end direction, higher holding strength can be secured. Further, at this time, the diameter of the inner peripheral surface of the tool body tip portion and the outer peripheral surface of the center member at the portion where the elastic member is interposed on the tip side of the tool body is set to the elastic member on the rear end side of the tool body. If the diameter is larger than the diameter of the portion in which the center member is inserted, it is possible to prevent a situation where the elastic member on the rear end side hinders smooth separation when the center member is removed.

[0009]

1 to 6 show a first embodiment of the present invention.
FIG. In the present embodiment, the tool body 1 has a tip end side (see FIG. 1,
The right side in FIG. 2 has a substantially multi-stage cylindrical shape centered on the axis O having a diameter one step larger than the rear end side (left side in FIGS. 1 and 2), and the front end surface 2 thereof is made of carbide. A large number of chips 3 made of a hard material such as an alloy are implanted to form a cutting edge portion 4, and a male screw portion 5 is formed on the outer periphery of the rear end portion. The male screw portion 5 is hollow. By being engaged with a female screw portion formed on the inner periphery of the tip end portion of a driving force transmission means (not shown) such as a cylindrical rod,
The excavating tool is attached to the tip of the driving force transmitting means, is rotated around the axis O, and receives a striking force on the tip side in the direction of the axis O so that the cutting edge portion 4 of the tip surface 2 forms an excavation hole. Do it. It should be noted that the tip end surface 2 is a cone from the opening in the tip end surface 2 of the inner peripheral portion 6 of the tool body 1 having a substantially cylindrical shape toward the outer peripheral side, once toward the front end side, and then toward the rear end side. It is formed in a plane-inclined "V" shape as shown in FIG. 3, so that the inner peripheral side of the tip surface 2 is formed in a concave shape.

Further, on the outer periphery of the large diameter tip portion of the tool body 1, there are a plurality of articles (four articles in this embodiment) extending from the tip surface 2 in the direction of the axis O with a substantially arcuate cross section. The concave grooves 7 are formed at substantially equal intervals in the circumferential direction, and some of the concave grooves 7 (in this embodiment, two concave grooves located on the opposite sides of the axis O in FIG. Groove 7,
7) ... The groove depth is constant, that is, the groove bottom surface is formed to extend substantially parallel to the axis O, while the remaining groove 7 is formed.
(In this embodiment, the two recessed grooves 7, 7 on the upper and lower sides in FIG. 2, which are also located on the opposite sides of the axis O), have groove depths that gradually become shallower toward the rear end side. That is, the groove bottom surface is formed so as to face the outer peripheral side toward the rear end side.

Further, from the inner peripheral portion 6 of the tool body 1 toward the outer periphery of the tip portion, a plurality of branch holes 8 are formed obliquely with respect to the axis O so as to be directed toward the outer peripheral side toward the tip side. The branch holes 8 ... Are opened on the bottom surface of some of the grooves 7. Then,
In the present embodiment, the compressed air is supplied to the tool body 1 through the driving force transmission means during excavation, and the compressed air thus supplied is supplied from the inner peripheral portion 6 through the branch hole 8. The chips which are ejected from some of the above-mentioned recessed grooves 7 in which the branch holes 8 are opened and which are generated by the cutting blade portion 4 excavating the ground at the time of excavation are not recessed in the branch holes 8. It is configured to be discharged to the rear end side through 7.

A center member 9 is removably attached to the distal end side of the inner peripheral portion 6 of the tool body 1 by inserting it from the distal end side. An annular elastic member 10 that is elastically deformable in the radial direction is interposed between the opposing outer peripheral surface of the center member 9 along the peripheral direction of the inner and outer peripheral surfaces. Here, most of the inner peripheral portion 6 on the rear end side is a large diameter portion 6A having a circular cross-section with a constant inner diameter centered on the axis O, and the branch hole 8 is formed on the tip side of the large diameter portion 6A. And the tip side thereof is slightly reduced in diameter to form a small diameter portion 6B having a circular cross section with a constant inner diameter centered on the axis O, and the elastic member 10 has an inner circumference of the small diameter portion 6B. It is interposed between the outer peripheral surface of the center member 9 and the outer peripheral surface of the center member 9 facing each other.

Further, on the tip side of the small diameter portion 6B, there is a conical taper portion 6C which is gradually centered on the axis O and which gradually increases in diameter with a constant taper angle toward the tip side. The inner peripheral portion 6 on the tip side of the tapered portion 6C, which is open to the tip surface 2, has a substantially square cross section with one side larger than the inner diameter of the small diameter portion 6B. It is a joint 6D. In addition, in the cross section orthogonal to the axis O, each corner of the square formed by the fitting portion 6D is smoothly in contact with the side by a quarter concave arc centered at a position eccentric to the outer circumference from the axis O. As a result, a flat surface extending in the direction orthogonal to the axis O is formed around the opening edge of the tapered portion 6C to the fitting portion 6D, particularly in the periphery of this corner portion. Will be done.

On the other hand, the center member 9 attached to the inner peripheral portion 6 is fitted into the small-diameter portion 6B from the rear end side which is the insertion direction side into the inner peripheral portion 6 toward the front end side. A columnar portion 9A having a circular cross section having a possible outer diameter, and a conical taper portion 9 having a short width capable of closely adhering to the tapered portion 6C which gradually expands at a constant taper angle toward the tip side.
B, and a fitting portion 9C having a substantially square cross-section that can be fitted to the fitting portion 6D (however, each corner portion thereof is formed by a 1/4 convex arc so as to smoothly contact the side portion). And are integrally formed so that the center lines of the respective cross sections are coaxial with each other, and the center lines are attached so as to coincide with the axis O. Therefore, the elastic member 10 is interposed between the outer peripheral surface of the columnar portion 9A and the small diameter portion 6B.

Further, in the state of being attached to the tool body 1 as described above, the front end surface of the fitting portion 9C and the portion of the rear end surface around the tapered portion 9B are flat surfaces extending in the direction orthogonal to the axis O. When the tapered portions 9B and 6C are formed in close contact with each other, the flat surface portion of the rear end surface of the fitting portion 9C and the flat surface portion of the fitting portion 6D can be brought into contact with each other, and the fitting is performed. The thickness of the portion 9C in the direction of the axis O is substantially equal to the depth of the fitting portion 6D. Therefore, the tip end surface of the fitting portion 9C is located at the deepest portion in the center of the tip end surface 2 of the tool body 1 which is concave. Located. Further, a tip 3 made of a hard material is also planted on the tip surface of the fitting portion 9C, and the cutting blade portion 4 is configured with the tip 3 ...

Further, in this embodiment, in this embodiment, the inner peripheral surface of the small diameter portion 6B of the inner peripheral portion 6 of the tool body 1 and the outer peripheral surface of the columnar portion 9A of the center member 9 are opposed to each other in the present embodiment. As shown in FIG. 5, a mounting groove 11 having a substantially U-shaped cross section is provided on the side of the columnar portion 9A, and a small diameter portion 6B.
Pressing grooves 12 each having a depth smaller than that of the mounting groove 11 are formed annularly around the axis O, and the elastic member 10 is inserted into the mounting groove 11 to press the bottom surface of the pressing groove 12. It is possible to install. Here, this elastic member 1
0 is made of an elastically deformable material such as rubber, resin, or metal. When made of rubber or resin, it has an annular shape as shown in FIG. 6 (a), or when made of metal or resin. Figure 6
As shown in (b), it is C-shaped and its cross section is shown in FIG.
As shown in FIG. 3, the circular shape is obtained by inserting the center member 9 into the inner peripheral portion 6 of the tool body 1 after being inserted into the mounting groove 11 in a compressed state on the inner peripheral side with respect to the axis O. By the elastic force of returning to the original state, it is possible to extend to the outer peripheral side and press the groove bottom surface of the pressing groove 12.

When the elastic member 10 is formed of rubber or resin into an annular shape, the elastic member 10 is compressed so as to be crushed toward the inner peripheral side in the mounting groove 11 and the elastic force of the material itself is applied. When the elastic member 10 is expanded to the outer peripheral side and is C-shaped by a metal or a resin, the elastic member 10 is compressed so as to be reduced in diameter and expanded to the outer peripheral side by its repulsive force. Therefore, in the latter case, a shrinkage allowance for allowing the diameter reduction of the elastic member 10 is given to the groove bottom side of the mounting groove 11, and the elastic member 10 expands to the outer peripheral side to press the pressing groove 12, A slight gap is defined between the groove bottom of the mounting hole 11 and the elastic member 10.

Further, in this embodiment, the pressing groove 12 on the tool body 1 side has a cross section along the front-rear direction of the tool body 1 on the bottom surface of the groove, that is, a cross section along the axis O direction shown in FIG. Thus, the groove bottom side has a concave arc shape with a large radius, and the small diameter portion 6B is formed from the pressing groove 12 on both sides thereof.
The open groove edge side to the inner peripheral surface is formed to have a convex arc shape having a smaller radius than the concave arc smoothly connecting to the groove bottom side and the inner peripheral surface of the small diameter portion 6B. As a result, on the tip side (right side in FIG. 5) of the tool body 1 in the pressing groove 12, an inclined curved surface 12A is formed which is concave and convex toward the inner peripheral side of the tool body 1 as it goes toward the tip side. Become.

As described above, the pressing groove 12 is formed in the tool main body 1.
Instead of forming the above-mentioned cross section of the bottom surface of the groove so as to have the concavo-convex arc shape as described above when located on the side, for example, as in the modification shown in FIG. The portion of the rear end side (left side in FIG. 7) extending to the edge of the open groove has a concave arcuate cross section at the groove bottom surface, and the tip side of the tool body 1 in the pressing groove 12 (FIG. The right side) has a linear sectional shape in which a tangent line contacting the concave arc extends toward the inner peripheral side toward the tip side, and this portion is formed on the inclined surface 12A.
You may ask.

Therefore, in the excavating tool constructed as described above, the excavating tool is rotated around the axis O by the driving force transmitting means such as a rod during excavation as described above, and receives a striking force on the tip side in the axis O direction. When forming the drill hole, the elastic member 10 interposed between the inner peripheral surface of the inner peripheral portion 6 of the tool body 1 and the outer peripheral surface of the center member 9 is not elastic in this embodiment due to its elastic force. Since the pressing groove 12 on the inner peripheral surface is pressed, the center member 9 can be securely held on the inner peripheral portion 6 and its falling can be prevented.
In this way, it is possible to prevent a situation in which the center member 9 is lost during excavation and chips enter the tool body 1 to hinder smooth excavation. On the other hand, after excavation, the center member 9 is attached to the tool body 1
When separating from the above, the rear end of the center member 9 is pushed by an anchor or the like to project the center member 9 toward the tip side, so that the elastic member 10 is elastically deformed and pushed out from the pressing groove 12 in this embodiment. The outer diameter of the center member 9 is reduced, so if you push it out, the center member 9
Can be dropped from the inner peripheral portion 6 of the tool body 1 to be separated.

Further, in this embodiment, the elastic member 10 is used.
The elastic member 10 is inserted on the inner peripheral surface of the inner peripheral portion 6 of the tool body 1 and the outer peripheral surface of the center member 9, in which the elastic member 10 is disposed on the outer periphery of the columnar portion 9A. The mounting groove 11 to be attached is attached to the inner circumference of the small diameter portion 6B of the inner circumference 6 of the tool body 1 side.
2 are formed so as to face each other in the attached state. Further, on the groove bottom surface of the pressing groove 12, an inclined surface 12A is formed on the tip side of the tool body 1 toward the inner peripheral side toward the tip side, and the center member 9 is formed.
When the elastic member 10 is elastically deformed and pushed out from the pressing groove 12 when separating the
Since the outer diameter of the elastic member 10 is gradually reduced and extruded so as to be guided along 2A, elastic deformation of the elastic member 10 at the time of this separation is facilitated and the center member 9 is removed. It becomes possible to separate more reliably and easily. On the other hand, in the present embodiment, the inner peripheral portion 6 and the center member 9 are formed with taper portions 6C and 9B which have a small width in the direction of the axis O but which gradually expand in diameter toward the tip side and which can be in close contact with each other. Therefore, the holding strength of the center member 9 at the time of excavation can be more reliably ensured.

In this embodiment, the mounting groove 11 is formed on the side of the center member 9 as described above, and the tool body 1
The pressing groove 12 is formed on the side, and the annular or C-shaped elastic member 10 is inserted into the mounting groove 11 in a contracted state and is expanded to the outer peripheral side by its elastic force and repulsive force to press the pressing groove 12. The center member 9 is held on the inner peripheral portion 6 of the tool body 1 by pressing 12. However, conversely, the mounting groove 11 is pressed on the tool body 1 side and the center member 9 side is pressed. The groove 12 is formed, and the annular or C-shaped elastic member 10 is attached to the attachment groove 11 in a state where the elastic member 10 is elastically deformed so that the inner diameter is enlarged, and the elastic member 10 contracts to the inner peripheral side by the elastic force and the repulsive force. Thus, the pressing groove 12 may be pressed to hold the center member 9. Then, in this case, the inclined surface 12A of the pressing groove 12 formed on the center member 9 side is directed to the rear end side portion of the tool body 1 in the pressing groove 12 and to the outer peripheral side toward the rear end side. Thus, it is formed to be inclined.

On the other hand, in this embodiment, a fitting portion 6D having a larger cross section than the small diameter portion 6B or the tapered portion 6C on the rear end side is formed on the tip side of the inner peripheral portion 6 of the tool body 1, and A fitting portion 9C capable of fitting to the fitting portion 6D is formed on the tip end side of the center member 9, and the center member 9 includes the columnar portion 9A on the rear end side of the fitting portion 9C and the small diameter portion 6B.
The taper portion 9B and the taper portion 6C.
Then, the fitting portion 9C is fitted to the fitting portion 6D and attached to the inner peripheral portion 6. Since these fitting portions 6D and 9C are formed in a polygonal shape whose cross section orthogonal to the axis O is substantially square, the rotational force transmitted from the driving force transmitting means to the tool body 1 is It is also transmitted to the center member 9 via the side surfaces (peripheral surfaces around the axis O) of the fitting portions 6D and 9C having a polygonal shape. Therefore, according to the present embodiment, even when the cutting edge portion 4 is configured by implanting the tips 3 on the tip surface of the center member 9 as described above, the tip 3 of the center member 9 ensures the reliability. In comparison with the case where the center member and the inner peripheral part of the tool body are circular in cross section as a whole, the direction of rotation that acts on the center member during excavation is opposite It is also possible to prevent a situation in which the center member is rotated and is disengaged from the inner peripheral portion due to a directional load.

Further, in this embodiment, the flat surface of the rear end surface of the fitting portion 9C of the center member 9 and the flat surface of the fitting portion 6D of the inner peripheral portion 6 of the tool body 1 are brought into contact with each other in the mounted state. Therefore, the impact force to the tip side in the direction of the axis O of the tool body 1 transmitted by the driving force transmission means at the time of excavation can be surely transmitted to the center member 9 through these flat surfaces. Drilling can be encouraged. In this embodiment, the fitting portion 6 is
Although D and 9C have a substantially square cross-section, other shapes such as regular triangles and regular pentagons or other polygons may of course be used, and they may not be regular polygons. In addition, some or all of the corners and the like may be curved such as arcs.

Next, FIGS. 8 and 9 show a second embodiment of the present invention, in which the same parts as those of the first embodiment shown in FIGS. 1 to 7 are designated by the same reference numerals. The description is omitted here. Thus, in the present embodiment, the small diameter portion 6B in the inner peripheral portion 6 of the tool body 1 has a circular cross-section with a constant inner diameter that communicates with the large diameter portion 6A in order from the rear end side to the tip side. The first small diameter portion 6a, the second tapered portion 6b having a conical surface shape centered on the axis O that gradually expands at a constant taper angle toward the tip side in the direction of the axis O, and the first small diameter portion 6a.
Second small-diameter portion 6 having a circular cross section with a constant inner diameter larger than
c and the second small diameter portion 6 is the small diameter portion 6
The taper angle of the second taper portion 6b is made equal to the taper angle of the second taper portion 6b while being communicated with the above-mentioned taper portion (first taper portion with respect to the second taper portion 6b) 6C on the tip side of B.

In accordance with this, the columnar portion 9A of the center member 9 also has a columnar shape (circular shape) of a constant outer diameter which can be fitted into the first small diameter portion 6a in order from the rear end side to the front end side. (A plate-like) first columnar section 9a and a second truncated cone section 9b of a truncated cone shape capable of closely contacting the second tapered section 6b.
And a second columnar portion 9c having a constant outer diameter and having a larger outer diameter than the first columnar portion 9a and which can be fitted into the second small diameter portion 6c are integrally and coaxially. Formed and configured. Further, the tapered portion (first tapered portion with respect to the second tapered portion 9b) 9B is provided on the tip side of the second columnar portion 9c, and the taper angle of the second tapered portion 9b is equal to that of the first tapered portion 9B. Therefore, the tapered portions 6C and 6b of the inner peripheral portion 6 are also equal.

In the present embodiment, the first and second columnar portions 9a, 9a of the columnar portion 9A of the center member 9 among them are used.
Mounting grooves 11 and 11 are formed on the outer peripheral surface of c, respectively, and at the inner peripheral portion 6 of the tool body 1, the small diameter portion 6 is formed.
On the inner peripheral surfaces of the first and second small diameter portions 6a, 6c of B, pressing grooves 12, 12 are formed at positions corresponding to the mounting grooves 11, 11 in the direction of the axis O, and the mounting grooves 11, 11 are formed. The elastic members 10, 10 inserted in the inner peripheral surface of the inner peripheral portion 6 of the tool body 1 and the outer peripheral surface of the center member 9 are interposed so as to press the groove bottom surfaces of the pressing grooves 12, 12. ing. That is, a plurality of elastic members 10 ... Are interposed between the inner peripheral surface of the inner peripheral portion 6 of the tool body 1 and the outer peripheral surface of the center member 9 so as to be aligned in the front-rear end direction jamming axis O direction of the tool body 1. Has been done.

The individual elastic members 10, mounting grooves 11,
The shape of the pressing groove 12 may be the same as that of the first embodiment. However, each diameter is the first and second
Of the small diameter portions 6a, 6c and the first and second columnar portions 9a, 9c are different from each other, that is, a portion in which the elastic member 10 is interposed on the tip side of the tool body 1. The diameter of the inner peripheral surface of the inner peripheral portion 6 and the outer peripheral surface of the center member 9 is
The diameter is made larger than the diameter of the portion where the elastic member 10 is interposed on the rear end side of the tool body 1.

Therefore, according to the excavating tool of the second embodiment having the above-mentioned structure, the center member 9 has the tool body 1
The inner peripheral surface 6 of the first and second small diameter portions 6a and 6c of the small diameter portion 6B and the first and second columnar portions 9a and 9c of the columnar portion 9A of the center member 9, respectively. Since it is held by the above-mentioned two elastic members 10 and 10 interposed between the two, it is possible to secure a higher holding strength than that of the first embodiment, and to more reliably prevent the center member 9 from falling off during excavation. Can be prevented. In addition, in the present embodiment, the taper portion also includes the first and second taper portions 6C on the inner peripheral portion 6 side,
6b and the first and second tapered portions 9 on the side of the center member 9
Since each of B and 9b can be brought into close contact with each other, it is possible to further secure the holding strength.

On the other hand, by providing the second tapered portions 6b and 9b in this way, the inner peripheral surface of the inner peripheral portion 6 of the tool body 1 in which the elastic members 10 and 10 are interposed is Since the outer peripheral surface of the columnar portion 9A of the center member 9 is formed so as to be gradually expanded in diameter toward the front end side, when the center member 9 is pushed out from the rear end side and pulled out, The elastic member 10 attached to the first columnar portion 9a on the end side may be caught in the pressing groove 12 of the second small diameter portion 6c on the front end side of the inner peripheral portion 6 to hinder smooth extraction of the center member 9. This is not the case, and it is possible to maintain easy and reliable separability.

[0031]

As described above, according to the present invention,
By inserting an elastic member between the inner peripheral surface of the tool body and the outer peripheral surface of the center member, the center member can be easily and reliably separated when the center member is removed after the end of excavation, while the center member is being excavated during excavation. It is possible to reliably hold the member and prevent it from falling off.

[Brief description of drawings]

FIG. 1 is a side view showing a first embodiment of the present invention.

FIG. 2 is a front view of the first embodiment shown in FIG. 1 viewed from the tip side.

FIG. 3 is a sectional view taken along line ZOZ in FIG.

FIG. 4 is a center member 9 of the first embodiment shown in FIG.
(A) rear view seen from the rear end side, (b) side view,
(C) It is a front view.

5 is an elastic member 10 of the first embodiment shown in FIG.
FIG. 3 is an enlarged cross-sectional view showing the periphery of the mounting groove 11 and the pressing groove 12.

6A is a front view showing the elastic member 10 of the first embodiment shown in FIG. 1, and FIG. 6B is a front view showing a modified example of the elastic member 10.

FIG. 7 is an enlarged cross-sectional view showing the periphery of the elastic member 10, the mounting groove 11, and the pressing groove 12 in the modified example of the first embodiment shown in FIG.

FIG. 8 is a sectional view showing a second embodiment of the present invention and corresponding to the ZOZ section in FIG.

FIG. 9 is a center member 9 of the second embodiment shown in FIG.
(A) rear view seen from the rear end side, (b) side view,
(C) It is a front view.

[Explanation of symbols]

1 Tool body 4 cutting edge 6 Inner circumference of the tool body 1 6B, 6a, 6c Small diameter part 6C, 6b Tapered part 6D fitting part 9 Center member 9A, 9a, 9c Columnar part 9B, 9b Tapered part 9C fitting part 10 Elastic member 11 mounting groove 12 Press groove 12A inclined surface

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hitoya Hisada             1528, Nakashinden, Yokoi, Kobe-cho, Anpachi-gun, Gifu Prefecture             Address Ryotech Co., Ltd. Construction Tool Factory             Within (72) Inventor Kazuyoshi Nakamura             1528, Nakashinden, Yokoi, Kobe-cho, Anpachi-gun, Gifu Prefecture             Address Ryotech Co., Ltd. Construction Tool Factory             Within

Claims (6)

[Claims] 1. A center member is removably attached to the inner periphery of the tip of a tool body having a tubular shape by inserting it from the tip side, and the center of the inner periphery of the tip of the tool body is opposed to the inner surface. An excavating tool, wherein an annular elastic member that is elastically deformable in the radial direction is interposed between the outer peripheral surface of the member and the inner peripheral surface of the member. 2. A mounting groove into which the elastic member is inserted and an elasticity of the elastic member inserted into the mounting groove are provided on the inner peripheral surface of the tip end portion of the tool body and the outer peripheral surface of the center member. A pressing groove whose bottom surface is pressed is formed to face each other, and when the pressing groove is on the tool body side, the tip is located on the tool body tip side on the groove bottom surface of the pressing groove. The inclined surface toward the inner peripheral side toward the side, and the inclined surface toward the outer peripheral side toward the rear end side is formed on the tool body rear end side when the pressing groove is on the center member side. The excavating tool according to claim 1, wherein the excavating tool is provided. 3. The tool according to claim 1, wherein at least a part of an inner peripheral surface of the tool body tip portion and an outer peripheral surface of the center member are formed in a polygonal cross-section capable of fitting with each other. The drilling tool according to claim 2. 4. A taper portion capable of adhering to each other and having a diameter gradually increasing toward the tip side is formed on at least a part of an inner peripheral surface of the tip portion of the tool body and an outer peripheral surface of the center member. The excavating tool according to any one of claims 1 to 3, wherein: 5. A plurality of elastic members are provided between the inner peripheral surface of the tool body tip and the outer peripheral surface of the center member.
The excavating tool according to any one of claims 1 to 4, wherein the excavating tool is interposed so as to be aligned in a front-rear end direction of the tool body. 6. The diameter of the inner peripheral surface of the tip end portion of the tool body and the outer peripheral surface of the center member at the portion where the elastic member is interposed on the tip end side of the tool body is the same as the rear end side of the tool body. The excavating tool according to claim 5, wherein a diameter of the elastic member is larger than a diameter of a portion of the excavating tool.