JP2002300816A - Tool for digging - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tool for digging, suitable for uses such as digging a shrub forest and waste land, cutting the roots of trees for a cultivation to make an arable land, and also for removing anti-personal mines. SOLUTION: This tool for digging is equipped with a holder fixed at a cylindrical base body supported by a traveling device and forcefully rotated, a pit mounted to the above holder as freely demountable, and an axial fixing tool for fixing these pit and holder. At the base part of one of the above pit and holder, a recessed part for engaging, and at the other part, a plate state part for engaging with the above recessed part is installed. These recessed part and plate state part for the engagement are equipped with a sloped surface having a low front side and high rear side in digging as a contacting surface with each other, and also installed with each of penetrating holes for inserting a fixing tool and overlapping each other in engaging state of both of them, and the above pit has its tip end part which is formed as a forward tilting shape tilting forward by a prescribed angle based on its base part in the rotating direction of the cylindrical base body in its fixed state to the holder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to excavating shrub forests and wasteland, cutting tree roots and the like, and clearing and cultivating the land.
The present invention relates to a drilling tool suitable for use in removing antipersonnel mines.

[0002]

2. Description of the Related Art Excavation in which a plurality of rows of bit mounting portions are provided on an outer peripheral portion of a cylindrical base body provided with a rotating mechanism at both ends in a horizontal axis direction, and a plurality of bits are mounted on each row by a fixing method such as welding. The device has been put to practical use. This excavator excavates the ground or the like with a bit protruding from the outer peripheral surface thereof while rotating a cylindrical base body. As the bit, a bit whose edge is hardened and hardened, or a bit in which a hard blade such as a carbide tip is fixed to the edge of a steel shank by brazing or the like is used.

[0003]

In the above conventional apparatus, when a bit fixed to a cylindrical base by welding or the like is worn, it is difficult to replace the bit, and the entire apparatus becomes unusable. It was economic. Therefore, a bit has been developed in which the bit can be attached to and detached from the base so that only the worn bit can be replaced.
At the time of use, a large reaction force acts on the bit, so that the mounting portion of the bit is often damaged or loose.

In order to solve this problem, an engaging recess is provided at one base of the bit or the holder, and a plate-like portion is provided at the other to engage with the recess. The excavator is shaped such that the front side is low and the rear side is high on the inclined surface at the time of excavation, and the bit and the holder are fixed to each other by a fixing tool comprising a shaft body on which a plastically deformable bush is fitted. A drilling tool configured to be fixed by being inserted into a drilling tool has been developed, and a patent application has already been filed (see JP-A-11-196610).

It has been confirmed that the newly developed excavating tool has a longer life than conventional ones, and that it is easy to change bits. Had a problem and sometimes spilled excavation during rotation. Further, since the bit is fixed to the holder with one fixture, the fixing is slightly unstable, and the holder may be deformed in long-term use. Further, there is also a problem that the holding strength of the cemented carbide tip fixed to the tip of the bit is not sufficient, and the tip is easily broken or dropped.

[0006]

In order to solve the above problems, the present invention employs the following configuration. That is, the excavating tool according to the first aspect of the present invention fixes a holder fixed to a cylindrical body that is forcibly rotated, a detachable bit attached to the holder, and the bit and the holder. A shaft-shaped fixing tool, wherein one of the bit and the holder is provided with a concave portion for engagement at a base portion, and the other is provided with a plate-shaped portion which engages with the concave portion. And the plate-shaped portion, the front side at the time of excavation is provided with an inclined surface having a low rear side as a contact surface with each other, and provided with through holes for fixing tool insertion overlapping each other in the engagement state of both, the bit is In a state in which the cylindrical base is fixed to the holder, the distal end thereof is formed in a forwardly inclined shape that is inclined forward by a predetermined angle in the rotation direction of the cylindrical base body with respect to the base.

Further, in the invention described in claim 2, two through holes are respectively provided in the plate-shaped portion and the concave portion, and a fixture is inserted into each of the through holes.

Further, according to the invention described in claim 3, the tip of the bit is provided with a groove extending in the axial direction of the bit, and a carbide tip protruding forward and upward is fitted into the groove and the wax is inserted. And a hardfacing layer is formed around the chip.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a preferred embodiment of the present invention.

This excavating tool 1 comprises holders 5 fixed to a cylindrical base 2 of a rotary excavator, and bits 7 individually attached to the holders. The base 2 is
As shown in FIG. 11, rotating devices 1 are provided at both left and right ends in the axial direction.
0 and 10 are provided, and during the excavation, the rotary device is forcibly rotated in a predetermined direction.

An arc-shaped bottom surface 5a is formed at the base of the holder 5 and is fixed to the circular outer peripheral surface of the base 2 by welding. Chamfers 5 for welding are provided on both sides of the bottom surface 5a.
b, 5b are given. At the time of welding, a round bar-shaped projection 5c provided on the bottom surface of the holder 5 is inserted into a hole provided on the outer peripheral surface of the base 2 for positioning, so that the arrangement of the holder is set as an efficient arrangement as set in advance. Is easy.
Instead of such projections, other positioning means may be employed, and in some cases, the holder need not be provided with positioning means. Note that the holders 5 for the base 2 are.
The number and arrangement may be optimized according to the conditions of use, and may be such as to provide a desired excavation efficiency, for example, by arranging spirally along the outer peripheral surface of the base 2.

The upper portion of the holder 5 has a substantially mountain shape in a side view, and the thick support portions 1 are provided on the front side and the rear side in the rotation direction, respectively.
2 and 13 are provided, and a thin plate-like portion 15 having an inclined surface having a low front side as an upper surface 15a is formed at an intermediate portion between the two. The height of the front support portion 12 is considerably lower than the height of the rear support portion 13, and the rear surface 12 a of the front support portion 12 and the front surface 13 a of the rear support portion 13 are provided.
Are each formed as a flat support surface inclined forward by an angle α with respect to the center axis CL of the holder 5. Both sides of the front portion of the front support portion 12 are formed as inclined surfaces 12b, 12b such that the front side is sharp in a plan view, and a narrow width rib 13b is formed on the rear portion of the rear support portion 13. I have.

At a position near the lower part of the plate-like portion 15 of the holder 5, two insertion holes 19, 19 penetrating right and left are provided at appropriate intervals, for example, at intervals of 10 to 20 mm. A fixture for fixing the bit is inserted into these two insertion holes 19, 19.

The bit 7 is a steel shank (metal) 2
A blade 23 of a carbide tip is fixed to the head 22 by brazing. A fitting groove 25 is cut into the shank portion 21 upward from the base bottom surface.
5 are bifurcated legs 21a and 21b. The fitting groove 25 is shallow on the front side and deeply cut on the rear side, and the surface 25a forming the groove bottom is an inclined surface corresponding to the plate-like portion 15 of the holder in a side view.
The base of the shank 21 is provided with the legs 21a, 2a.
1b, two insertion holes 27, 27 for inserting a fixture.
Is provided. Of these insertion holes 27, a portion formed on one leg portion 21a side with the fitting groove 25 interposed therebetween is a dish-shaped portion 27a in which a head 30a of a bolt 30 as a fixing tool is embedded. , The screws are not cut.
Further, a hole portion provided in the leg portion 21b on the opposite side with respect to the fitting groove 25 is a screw hole 27b into which the bolt 30 is screwed.

The head 22 of the bit 7 is inclined forward by an angle β with respect to the axis (n) of the base of the shank. A line (m) representing this inclination is an inclined surface 2 at the groove bottom of the shank portion.
It is a line connecting the intersection of 5a and the axis (n) of the shank with the point P of the head. The back surface 22a of the head 22 is also inclined forward by γ with respect to the axis (n). Although these inclination angles β and γ depend on the shape of the head, it is usually preferable to be about 15 to 45 degrees in consideration of the cutting property and the scraping property of the excavated object. In addition, the upper surface 22b of the head is
The rear side has a slightly low slope to prevent resistance to rotary excavation. The fixing portion of the blade body 23 is formed with a groove 24 which opens vertically in the vertical direction from the upper end of the bit head, and the blade body (carbide chip) 23 is fitted into this portion and brazed. . The front surface and the upper surface of the blade body 23 of the carbide tip are formed in a mountain shape in cross section by inclined surfaces from both sides, and protrude forward and upward from the base metal portion.

A hardfacing layer (hard facing) 28 is formed from the front surface to the side surface at the corner immediately below the bit edge where the blade body 23 of the carbide tip is implanted.
Abrasion resistance is enhanced. As described above, since the hardfacing layer is formed on the corner portion on the front side of the blade edge portion, where wear is particularly severe, the life of the bit can be greatly improved without increasing the cost so much.

The fixture 30 for fixing the bit 7 to the holder 5 is a hexagon socket head bolt having a dish-shaped head in the illustrated example. In addition, bolts of other shapes as fixtures,
Screws, pins, etc. can be used, but if they protrude to the side of the bit, they will wear quickly during excavation. It is preferable not to protrude from the surface. A plastically deformable bush 31 made of nylon is fitted around the head of the fixing device 30, and the lower screw portion is exposed. The bush 31 may be made of any material that can be plastically deformed to some extent and can hold the fixture firmly without play or play when the fixture is inserted into the engagement portion. A cylindrical body made of a soft metal such as copper or aluminum can be appropriately used. In some cases, this type of bush may not be used.

The excavating tool 1 is used by fixing holders 5,... To an outer peripheral portion of a cylindrical base body 2 in an appropriate arrangement.
The holders 5,... Are preferably arranged in rows at appropriate intervals on a plurality of lines along the axial direction of the base 2. In this case, it is effective to arrange the holders of the adjacent holder rows in a staggered shape in a plan view by shifting the positions in the front-back direction in the horizontal direction. The arrangement of the holder is not limited to this, but may be any as long as effective excavation is performed over a wide range by rotation of the base.

Bits 7,... Are respectively attached to the holders 5,. In this attachment, the plate-like portion 15 of the holder is fitted into the fitting groove 25 of the bit, and the two bolts 30, 30 serving as fixing tools are inserted into the insertion holes 27, 27 of the two leg portions 21 a, 21 b of the bit. This is performed by inserting and screwing into the insertion holes 19, 19 of the portion 15, respectively. The attachment and detachment of this bit is easy. In this case, the bush 31 fitted to the outer peripheral portion is forcibly fitted into the insertion hole so that the bolt 30 which is the shaft of the fixture is not loosened.

When a large number of bits 7,... Are mounted on the outer peripheral portion of the base 2, the base is mounted on an arm 41 of a crawler type traveling device (or a wheel type traveling device) 40 as shown in FIG. In a pressed state (in some cases, it may be simply placed), the rotating devices 10 and 10 using a hydraulic motor as a driving source are forcibly rotated in a predetermined direction. By this rotation, the excavation is performed by the bits 7, while the base 2 rolls in a predetermined direction. Since the hard blade 23 is planted at the tip of the bit, excavation can be performed well even if there is a tree root or a stone. Since the head of the bit 7 is tilted forward with respect to the axis of the shank, excavated earth and sand, excavated land mines, etc. can be successfully scooped up by the head of the bit along the rotation direction, and effective excavation can be performed. Done.

Most of the forces acting on the bit during excavation are caused by the contact surfaces of the support portions 12 and 13 with the bit 7, the inclined surface 15a of the plate-like portion 15 of the holder, and the inclined surface 25b of the bit fitting groove 25. Is supported by the contact portion. The traveling device 40 in the illustrated example includes a cover 43 instead of a shovel of a hydraulic shovel.
The excavated material, which is provided with the attached base 2 and is scraped up by the bit 7, is prevented from being scattered by the inside of the cover 43.

In this excavating tool 1, the bit 7 is
However, since the height of the front portion (supporting portion 12) in the rotation direction of the base 2 in the exposed portion of the holder is low and the height of the front exposed surface of the bit 7 is high, During the operation, the bit 7 is mainly worn and the holder 5 is hardly worn. Therefore, when a bit is worn, it can be reused by replacing only the bit. The bit 7 is provided with a vertical groove at the cutting edge thereof, and a hard blade body (carbide tip) 23 having a front end pointed in a mountain shape.
Is fitted and brazed, so that the cutting property of the bit head is good. The front side immediately below the cutting edge of the bit 7 is liable to be worn during use, particularly at the corners thereof, but the bit 7 has a hardfacing layer 28 as shown in FIG.
Is formed, early wear of this portion can be prevented, and the life of the bit is greatly improved.

In the excavating tool 1, two bits 27 and 27 are provided in the bit 7 and the holder 5, respectively, and the bit is fixed by two fixing tools 30 and 30 inserted into the respective holes. As a result, the torque acting on the bit 7 during rotary cutting is also supported by these two fixtures,
Wear and damage of the support surfaces 12a and 13a of the holder are less likely to occur.

When this excavator is used for removing antipersonnel mines, it is preferable from a safety viewpoint that the excavator be moved on the target ground by remote control or the like. Further, in the above description, the case where the holder is used by attaching to the cylindrical base 2 is exemplified, but the shape of the base is not limited to this, and the holder can be used by attaching to a base of another shape. .

[Brief description of the drawings]

FIG. 1 is a side view in an assembled state showing a specific example of the present invention.

FIG. 2 is a front view (a) and a side view (b) of a holder.

FIG. 3 is a plan view of a holder.

FIG. 4 is a view of the holder as viewed from an arrow X.

FIG. 5 is a sectional view taken along the line YY of the holder.

FIG. 6 is a front view (a), a side view (b), and a rear view (c) of a bit.

FIG. 7 is a plan view of a bit.

FIG. 8 is an explanatory view of a fixture.

FIG. 9 is a cross-sectional view illustrating a state in which a fixture is inserted into a bit.

FIG. 10 is a side view showing a state where the holder is fixed.

FIG. 11 is a front view (a) and a side view (b) of a main part of the excavator.

FIG. 12 is an overall view of a drilling rig.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Excavation tool 2 Base 5 Holder 7 Bit 10 Rotating device 12 Front support part 13 Rear support part 15 Plate part 19 Insertion hole 21 Shank part 22 Head 23 Blade body (carbide chip) 25 Fitting groove 27 Insertion hole 30 Bolt (adhesion means) 31 Bush

Claims (3)

[Claims] A holder fixed to a cylindrical substrate that is forcibly rotated, a detachable bit attached to the holder, and a shaft-shaped fixture for fixing the bit and the holder. One of the base of the bit and the holder is provided with a concave portion for engagement, and the other is provided with a plate-shaped portion which engages with the concave portion. The lower rear side is provided with a high inclined surface as a contact surface with each other, and through holes for fixing tool insertion overlapping each other in an engagement state of both are provided,
An excavating tool, wherein the bit is formed in a forwardly inclined shape in which a tip portion thereof is inclined forward by a predetermined angle with respect to a base in a rotation direction of the cylindrical base when fixed to a holder. 2. The excavating tool according to claim 1, wherein two through holes are provided in each of the plate-shaped portion and the concave portion, and a fixture is inserted into each of the through holes. 3. A bit is provided at the tip of the bit along the axial direction of the bit, and a carbide tip projecting forward and upward is fitted into the groove and brazed. The excavating tool according to claim 1, wherein a hardfacing layer is formed in the portion.