JPH0835387A - Drilling bit for boring and the like - Google Patents

Abstract

PURPOSE:To provide a drilling bit for boring and the like in which some parts of the drilling bits are formed into movable bits which can expand and move to restore freely. CONSTITUTION:While movable bits 1b are engaged and provided allowable /to expand and to move to restore at the left side and the right side positions of a main bit 1a by making the center 3 of the main bit 1a as the center, an eccentrical circular arc form of cam A (a recesses groove or a projecting line) provided to the lower end face of a main shaft 2, or to the lower side of a disk 4 fixed to the lower end of the main body 2; and a circular arc form of cam B (a projection or a recessed groove) provided on the upper surface of both movable bits 1b and 1d; are engaged. By the rotation of the cam A by rotating the main shaft 2 regularly, both movable bits 1b and 1b integral with the cam B engaged with the cam A move expanding at the eccentric size of the cam A to the outer side, and by the reverse rotation of the cam A by the reverse rotation of the main shaft 2, both movable bits 1b and 1b integral with the cam B engaged with the cam A move to restore at the eccentric size of the cam A to the inner side.

Description

Detailed Description of the Invention

[0001]

[Industrial field of use] Attached to the tip of a main shaft and involved in a drill bit for drilling and drilling various types of ground, especially in the method of burying a protective pipe (steel pipe) in parallel with the drilling. By expanding a part of the machining bit to form a moving bit that can be restored and moved freely, the moving bit is expanded and machined during machining, and when the machining bit is pulled out through a protective tube for replacement. Provides a cutting bit for boring, etc., in which the moving bit can be restored and reduced so that it can be easily pulled out and replaced.

[0002]

2. Description of the Related Art A cutting bit (a large number of bits projecting on the front surface) is attached to the tip of a rotationally driven main shaft, and boring of various types of ground such as rock and gravel stone layer, and various types of pipe burial cutting Etc., and particularly when performing long-distance excavation, the excavation bit is worn and damaged, so it is necessary to replace the excavation bit during the excavation.

In this case, the main axis is external (starting point / ground surface,
It is necessary to remove the excavation bit at the tip and replace it, but it is not easy to pull it out through the excavation hole due to friction with the inner wall of the hole, etc. In the case of the method of burying the protection pipe (steel pipe) in parallel with the progress of the progress of the burial of the pipe,
Naturally, since the inner diameter of the protection tube is smaller than the outer diameter of the machining bit at the tip, it is impossible to pull out the machining bit through the protection tube.

Therefore, in order to pull out through the protection tube for exchanging the machining bit, it is necessary to reduce the outer diameter of the machining bit as compared with that during machining.

Regarding the solution of the above-mentioned problems, in the past, for example, although not shown in the figure, the cutting bit is divided and
When the main shaft is pressed and rotated forward (cutting), a wedge-like object moves forward to open the split bit to the surroundings for cutting, and when pulling out the cutting bit for replacement, reverse rotation of the spindle causes the wedge to rotate. Something like is going backwards and shrinking bits are shrinking, so
Those that can be pulled out and replaced through the protective tube,
In addition, various trials have been made, but in any case, the expansion bit of the cutting bit cannot be expanded and contracted smoothly, and in particular, there is a problem that excavation earth and sand enter the gap generated during the operation and malfunction occurs. The current situation is that, with frequent occurrence, effective means are not yet provided.

From the above, the expansion / reduction operation of the cutting bit can be variously designed, but in consideration of the use condition of the cutting bit, the operating components are sealed, closely contacted, or closed. One of the challenges is to make sure that there is no gap for the entry of earth and sand.

Therefore, the present invention effectively solves all the above-mentioned conventional problems.

[0008]

SUMMARY OF THE INVENTION That is, the present invention relates to a circular cutting machine which is detachably and replaceably attached to the tip of a main shaft which is driven to rotate and which performs drilling and drilling of the ground such as boring and various pipe burials. In the advance bit, the movable bit is expanded and restored to the left and right positions around the center of the main bit, and the eccentricity is provided on the lower end surface of the main spindle or the bottom surface of the disk fixed to the lower end of the main spindle. An arcuate cam A (concave groove or ridge) and an arcuate cam B (projection or groove) provided on the upper surfaces of both moving bits are provided in engagement with each other, and the cam A is formed by forward rotation of the main shaft. Rotation, the two moving bits integrated with the cam B engaged with the cam B expand outward by the eccentric dimension of the cam A, and the reverse rotation of the main shaft causes the reverse rotation of the cam A to cause the cam B to engage with the cam B. Both moving bits move inward by the eccentric dimension of cam A. Characterized by comprising as,
The problem has been solved by using the cut bits for boring and the like.

[0009]

EXAMPLES Next, an example of the present invention will be described. The main shaft 2 which is rotationally driven is detachably attached to the tip of the main shaft 2 so as to be used for boring, various pipe burial and other ground drilling. In circular cutting bit 1 to be performed,

The movable bit 1b is opened and restored at the right and left positions around the central portion 3 of the main bit 1a so that the movable bit 1b can be restored and moved, and the lower end surface of the main spindle 2 or the lower surface of the disk 4 fixed to the lower end of the main spindle is installed. The eccentric arcuate cam A (concave groove or ridge) provided in the above and the arcuate cam B (projection or concave groove) provided on the upper surfaces of both moving bits 1b, 1b are engaged and provided,

When the cam A is rotated by the forward rotation of the main shaft 2, both moving bits 1b and 1b integrated with the cam B engaged with the main shaft 2 are expanded outward by the eccentric dimension of the cam A, and the main shaft 2 is rotated in the reverse direction. By the reverse rotation of the cam A by the cam, the both moving bits 1b, 1b integrated with the cam B engaged with the cam B are provided so as to restore and move inward by the eccentric dimension of the cam A. is there.

A more specific embodiment of the above embodiment will be described with reference to the drawings. The outer diameter of the main bit 1a is smaller than the inner diameter of the protective tube 5, and the lower end of the main shaft 2 has an eccentric arc shape on the lower surface. Of the moving bits 1b and 1b, to which the cam disk 4 having the cam A (concave groove) formed therein is fixed, and the cam A can be moved to the left and right positions around the central portion 3 of the main bit 1a.
A cover disc 6 fitted over the disc 4 is fixed to the upper surface of the main bit 1a in a state of being engaged with the disc 4, and the disc 4 is rotatably provided in the cover disc 6 formed in a sealed state. ,

The moving bits 1b and 1b are installed on the main bit 1a by placing the moving bits 1 and 2 in the left and right positions of the central portion 3 of the main bit 1a.
Of the moving bits 1b, 1b are provided with convex rails 8 (or concave rails) on the inner side surfaces of the left and right sides thereof.
(Or ridge) to engage both moving bits 1b, 1b
Is provided at the left and right positions of the central portion 3 of the main bit 1a so as to be freely opened and restored.

The cam A on the spindle 2 side and the moving bit 1b
When one of the side cams B is formed as a grooved cam, the other side cam B is formed as a convex ridge (protrusion), and both cams A and B are provided so as to engage with each other.

The excavation bit 1 is exchanged, for example, by removing the connecting portion 10 of the main shaft 2 or by removing the cover disk 6 from the main bit 1a.

[0016]

Operation: When performing the retraction, the main shaft 2 is rotated forward. The cam A of the disk 4 at the tip of the main shaft 2 rotates by the forward rotation, and the cam B (moving bits 1b, 1b) engaged with the cam A rotates by the rotation of the cam A by the eccentric dimension at the central portion 3 of the main bit 1a.
From the left to the right in the expanding direction, and the cutting bit 1 as a whole rotates in the expanding moving position to perform the cutting. Therefore, the moving bits 1b and 1b rotate in the expanding position to the hole 11 ( In parallel with the cutting, the outer diameter of the protection tube that is sequentially buried in the cutting hole is larger than the outer diameter).

.. When it is necessary to continue the cutting as described above and replace the cutting bit 1 at the tip, when the main shaft 2 is rotated in the reverse direction, the cam B (moving bits 1b, 1b) engaged with the cam A in the opposite manner to the above is reversed. ) Is restored and moved from the left and right toward the central portion 3 by the eccentric dimension, and thus fits within the outer diameter of the main bit 1a which is smaller than the inner diameter of the protective tube. After exchanging with the cutting bit 1, insert it into the protective tube to reach the cutting portion.

Again, the spindle 2 is rotated in the forward direction, and the moving bits 1b, 1b are moved to the expanded position in the same manner as above, and the cutting is continued.

[0019]

[Effect] When the main shaft is rotated forward, the moving bits are moved to the expanded position by the action of the cams A and B, and the moving bit can be machined in that state. When the main shaft is rotated backward, the moving bits are restored and reduced by the action of the cams A and B. Since it can be moved, a hole with a diameter larger than the outer diameter of the progress bit (larger than the outer diameter of the protection tube) can be excavated, and when it is necessary to replace the progress bit, it can be moved. Restore the bit and restore it to its original outer diameter by moving it
It has an extremely excellent feature that it can be easily pulled out to the outside through the protection pipe (steel pipe) and can be replaced with a new bit, which allows for ground excavation and long distances that require exchanging the bit. The efficiency of cutting can be significantly improved.

The engagement operation of the cams A and B is performed from the outside in a cover disk which is hermetically sealed, and the engagement operation of the main bit and the moving bit is performed by the engagement of the concave groove and the ridge. Since the operation is performed in a state where it does not occur, there is an advantage that the operation can be surely performed at all times without the risk of the operation being disturbed by the intrusion of earth and sand or the like.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional front view of an embodiment of a cutting bit according to the present invention.

FIG. 2 is a bottom view of FIG.

FIG. 3 is a side view of FIG.

FIG. 4 is a front view, a plan view, a bottom view, and a right side view of a moving bit.

FIG. 5 is an explanatory view of the operation of cam A and cam B. When the spindle (disk) is rotated in the normal state in (a), the moving bit expands and moves as shown in (a) → (b), When the rotation is reversed in the state of (b), the moving bit is restored and moved as shown in (b) → (a).

FIG. 6 is an explanatory view showing a state in which a protection pipe (steel pipe) is fitted and installed in parallel with the carving by the carving bit of the present invention.

[Explanation of symbols]

 A CAM B CAM 1 Recessing Bit 1a Main Bit 1b Moving Bit 2 Main Axis 3 Central Part 4 Disc 5 Protective Tube (Steel Pipe) 6 Cover Disc 7 C-shaped Recess 8 Convex Rail 9 Recessed Groove 10 Coupling 11

Claims (5)

[Claims] Claim: What is claimed is: 1. In a circular machining bit, which is detachably and removably attached to the tip of a main shaft that is rotationally driven to perform boring machining, various pipe burial machining, etc. The eccentric arcuate cam A (concave groove) provided on the lower end surface of the main shaft or the lower surface of the disk fixed to the lower end of the main shaft, while the movable bit is expanded and restored to the right and left positions centering on the center of the shaft. Or convex ridges) and arcuate cams B (protrusions or concave grooves) provided on the upper surfaces of both moving bits are engaged with each other, and the cam A is rotated by the forward rotation of the main shaft to engage with it. Both moving bits integrated with the cam B expand and move outward by the eccentric dimension of the cam A, and the reverse rotation of the main shaft causes the reverse rotation of the cam A.
A cutting bit for boring etc., characterized in that both moving bits integrated with the cam B engaged therewith are provided so as to restore and move inward by the eccentric dimension of the cam A. 2. An outer diameter of the main bit is formed to be smaller than an inner diameter of the protective tube, and a cam disk having an eccentric arcuate cam A (concave groove) formed on the lower surface is fixed to the lower end of the main shaft. With the cam A engaged with the cam B of the moving bit that is movably provided at the left and right positions around the center of the main bit, the cover disk fitted over the cam disk is fixed to the upper surface of the main bit. The cutting bit for boring etc. according to claim 1, wherein the cam disc is rotatably provided in a cover disc formed in a hermetically sealed state. 3. A convex rail (or concave rail) is provided on the left and right inner side surfaces of a U-shaped concave portion for installing and fitting a moving bit formed at the right and left positions of the central portion of the main bit, and the concave portions on the left and right side surfaces of the moving bit are provided therein. The cutting bit for boring or the like according to claim 1, wherein both moving bits are provided so as to open and restore freely to the left and right positions of the central portion of the main bit by engaging with the groove (or the ridge). 4. A cam A on the spindle side and a cam B on the moving bit side.
When one of the two is formed as a concave groove cam, the other cam is formed as a convex ridge (protrusion) so that both A and B are engaged in concave and convex. Cut bits for 5. The excavation bit for boring etc. according to claim 1, wherein the excavation bit is exchanged by removing the connecting portion of the main shaft or by removing the cover disk from the main bit.