JP2557509Y2 - Cutting device for casing head - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting device fixed to the tip of a case head for drilling.

[0002]

2. Description of the Related Art A cutting device is attached to a tip end of a casing head used for drilling a hole such as a pile hole at predetermined intervals along a circumferential direction. This cutting device comprises a holder to be welded to a casing head and a cutting bit detachably attached to the holder, and rotates the casing head while pressing the cutting device against a surface of a hole to be ground such as the ground. Accordingly, an annular cutting is performed (for example, Japanese Utility Model Laid-Open No. 64-14293, and Japanese Utility Model Laid-Open No. 1-6).
9894). 2. Description of the Related Art Conventionally, this type of cutting device has two kinds of bits for outer side cutting (outer blade bit) and inner side cutting (inner blade bit) in the thickness direction of a casing head alternately attached in a staggered manner. A groove slightly wider than the thickness of the casing head was drilled. When any bit was damaged, the bit was removed from the holder and a new bit prepared separately was attached.

[0003]

[Problems to be solved by the invention] However, the mounting ratio of the bits for the outer side cutting and the inner side cutting is as follows.
It is difficult to prepare two types of bits with different arbitrariness in an appropriate number because they differ depending on the soil properties and other conditions at the site and the degree of wear of the bits. Must be arranged extra, which increases inventory and is uneconomical. Therefore, the present invention
An object of the present invention is to make it possible to use one type of bit for both an outer cutter and an inner cutter.

[0004]

In order to solve the above problems, the present invention employs the following configuration. That is,
The cutting device according to the present invention comprises a combination of a holder fixed to the tip of a cylindrical drilling case head and a detachable cutting bit attached to the holder.
The cutting bit is obtained by implanting a hard blade at the head of a steel base having fixing means for the holder at the base, and the cutting blade portion of the blade has a front shape viewed from the cutting direction, A chevron having a top deviated to either the left or right, and the side surface shape viewed from both left and right sides is formed in a chevron having a top in the center, and the holder is inclined in the cutting direction to move the bit back and forth. It is characterized in that it can be fixedly supported in any direction.

[0005]

The holder of the cutting device is oriented such that the cutting edge of the bit is inclined at a predetermined angle in the direction of rotation of the casing head, that is, in the direction of cutting. Are fixed at predetermined intervals by welding or the like. A bit is attached to this holder, but when the bit is attached in such a direction that the top of the mountain-shaped cutting edge is biased toward the outer surface side, it functions as an outer blade bit, and the opposite direction, that is, the top of the blade edge portion is biased toward the inner surface. When installed in an appropriate orientation, it functions as an inner blade bit. Therefore, one kind of bit can be used for both the inner cutter and the outer cutter.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments shown in the drawings will be described below. FIG. 1 and the following drawings show one embodiment of the present invention.
This cutting device 1 includes a holder 2 and a cutting bit 3.
In the cutting bit 3, a hard blade 7 having a sharp-edged cutting edge is implanted in a left-right groove 6 provided in the head of a steel base 5 in the form of a cutting edge. The hard blade 7 is made of a cemented carbide tip and has a top 9 when viewed from the cutting direction or the opposite side.
Are deviated to the left or right, and when viewed from the left and right side surfaces, both have a mountain shape in which the top is located at the center in the width direction. It is preferable that the position of the top 9 in the front view is within a range of １ ／ or less of the entire width from either the left or right end.

[0007] When viewed from the front, the base metal 5 is bifurcated at its lower part, and the interval is a square groove 10. A bolt hole 11 penetrating left and right is formed in the forked portion. A hardfacing layer 12 is provided around the hard blade 7.

The holder 2 is provided with a square groove 1 of the base metal of the bit 3.
A thin portion (bit fixing portion) 15 into which 0 is fitted is provided obliquely from the upper end, and a bolt hole 17 is formed in the center of the thin portion. The inclination angle θ of the bit fixing portion, that is, the thin portion 15 is such that an appropriate scooping angle is synthesized with the cutting edge of the attached bit.
Degrees or less. The ridge 19 of this portion is chamfered. The holder 2 has a cylindrical casing head 2.
Are welded to the notches 21,... The direction of the holder 2 is such that the thin portion 15 is inclined in the cutting direction, that is, the rotating direction of the casing head.

In this manner, the cutting bits 3,... Are attached to the multiple holders 2,.
Can be attached by fitting the gap portion 10 to the thin portion 15 of the holder and inserting and screwing a bolt 25 into the bolt holes 11 and 17 of both. Multiple cutting bits 3, ...
In general, the inner blade and the outer blade are alternately mounted with the front and rear reversed, but the ratio and arrangement thereof are appropriately adjusted according to soil conditions and other conditions. If the bolt is loosened, the bit 3 can be removed from the holder. In this way, the casing head in which a large number of cutting bits are alternately attached to the inside and outside is rotated by a driving device (not shown) and pressed against the surface to be excavated to perform annular excavation. Since the cutting bit is inclined in the rotation direction, an appropriate scoop angle is formed on the angled cutting edge. The core remaining on the core may be separately broken and removed. If any bit is damaged by drilling,
The damaged bit may be removed and a new bit may be attached.

[0010]

As is apparent from the above description, the cutting device according to the present invention can be used as either an inner blade or an outer blade by reversing one type of bit on a holder attached to a casing hesso. Can be made to function, so that the number of required parts is reduced and the number of stocks can be reduced as compared with the conventional case, which is extremely economical.

[Brief description of the drawings]

FIG. 1 is a front view of a cutting bit.

FIG. 2 is a left side view thereof.

FIG. 3 is a right side view thereof.

FIG. 4 is a front sectional view of a holder.

FIG. 5 is a side view thereof.

FIG. 6 is a plan view thereof.

FIG. 7 is a side view of the cutting device.

FIG. 8 is a front view thereof.

FIG. 9 is an external view of a cutter head.

[Description of Signs] 1 Cutting device 2 Holder 3 Cutting bit 7 Blade 9 Top

Claims (1)

(57) [Scope of request for utility model registration] 1. A combination of a holder fixed to a tip of a cylindrical drilling head and a detachable cutting bit attached to the holder, wherein the cutting bit is provided at a base with respect to the holder. A hard blade is implanted in the head of a steel base having fixing means, and the cutting edge of the blade has a top portion whose front shape viewed from the cutting direction is deviated left or right. In the shape of a chevron, the side shapes viewed from the left and right side surfaces are both formed in a chevron having a top in the center, and the holder is tilted in the cutting direction so that the bit can be fixedly supported in any of the front and rear directions. A cutting device for a casing head, which is formed.