JP2020114613A - Core drill bit - Google Patents

Abstract

To provide a core drill bit in which a core that is a cut remainder material can be easily taken out from the inside of a cylinder and thus workability is improved.SOLUTION: When a through hole is formed in a Hume pipe 20, a tip of a core drill bit 100 is placed to a cutting hole part of the Hume pipe 20 and is rotationally driven by a motor or the like. Then, cutting is performed by a top place tip 110. When cutting is going on and the top place tip 110 penetrates the Hume pipe 20, an outer diameter on a front face side of the cut columnar core 22 becomes larger than an inner diameter of a cylinder 102 since the tip of the top place tip 110 wears. However, a side face of the core 22 is cut by an inside tip 130, thereby reducing the diameter of the core 22. Therefore, even if the core 22 enters the cylinder 102, the core is caught by the inside tip 130 and does not enter the cylinder 102.SELECTED DRAWING: Figure 1

Description

The present invention relates to a core drill bit that is a cutting tool that uses a diamond tip or the like, and more specifically, to improvement in taking out a concrete core or the like generated in a cylinder.

As a conventional core drill bit, for example, there is one shown in Patent Document 1 below, in which a cylinder has a diameter corresponding to a hole formed in a cutting target such as a fume tube and a diamond tip for cutting is attached. The diamond tip is a sintered body of metal powder containing diamond, and a plurality of diamond tips are attached to the peripheral edge on the opening side of the cylinder at predetermined intervals. Specifically, first, a brazing filler metal is placed around the opening at a predetermined interval, and diamond chips are placed on the brazing filler metal. Then, by heating, the brazing material is melted, and the diamond tip is brazed and joined.

Utility model registration No. 3068416

FIG. 4A shows a state at the time of cutting, and the fume tube 20 is cut by the diamond tip 12 as the cylinder 10 rotates. In this case, when the cutting operation is repeated, the tip of the diamond tip 12 is worn and the corners are rounded off as shown in FIG. Then, the outer diameter on the surface side of the cut cylindrical core 22 becomes larger than the inner diameter of the cylinder 10, which may enter the cylinder 10 for some reason. Then, the state shown in FIG. 3C is obtained, and the core 22 is caught in the cylinder 10 and cannot be removed.

The present invention focuses on the above points, and it is possible to easily take out a core, which is a cut residual material, from a cylinder, and to provide a drill bit capable of improving workability. To aim.

The present invention is a core drill bit in which a plurality of upright chips for cutting an object are provided at a predetermined interval at the tip of a cylinder, and a plurality of inner tips are provided inside the tip of the cylinder. Is characterized by. According to one of the main aspects, a surface position of the inner chip is higher than an inner surface position of the heavenly chip inside the cylinder. According to another aspect, the inner tip is provided inside the portion sandwiched by the top field tips of the tip of the cylinder, or is provided at a constant interval. According to still another aspect, the top chip and the inner chip are brazed to the cylinder. According to still another aspect, a coupling tool with the rotation driving means is provided at the rear end of the cylinder. The above and other objects, features and advantages of the present invention will be apparent from the following detailed description and the accompanying drawings.

According to the present invention, the inner chip is provided inside the cylinder in addition to the heavenly chip, so that the core after cutting does not get caught in the cylinder and is easily caught by the core remaining in the cylinder. It can be taken out and the workability can be improved.

1 shows an embodiment of the present invention, (A) is a perspective view showing a main portion, and (B) is an overall sectional view. It is a figure which shows the mode at the time of cutting by the said Example. It is a figure which shows the principal part of the other Example of this invention. It is a figure which shows the mode at the time of cutting with the conventional core drill bit.

Hereinafter, the best mode for carrying out the present invention will be described in detail based on examples.

FIG. 1 shows a core drill bit according to a first embodiment of the present invention. The main part is shown in FIG. 7A, and the cross section along the rotational axis direction is shown in FIG. In these figures, diamond tips 110 are attached to the tip of the cylinder 102 of the core drill bit 100 at appropriate intervals. The diamond tip 110 is attached to the tip of the cylinder 102 by a method such as brazing similar to the background art described above. In order to distinguish the diamond tip 110 at the tip of the cylinder from the inner tip described later, it will be referred to as "heavenly tip" hereinafter.

A connecting portion 120 is provided at the rear end of the cylinder 102. The connecting portion 120 is configured by a diametrically enlarged portion 122 on the rear end side of the cylinder 102, a drive shaft 124 inserted into the diametrically enlarged portion 122, and a connecting pin 126 penetrating the diametrically enlarged portion 122 and the drive shaft 124. Has been done. The drive shaft 124 is rotationally driven by power means such as a motor (not shown). When the drive shaft 124 rotates, the cylinder 102 rotates via the connecting pin 126. In this example, the enlarged diameter portion 122 is formed, but the reduced diameter portion is formed depending on the diameter of the hole to be cut and the diameter of the drive shaft 124. Various structures are known as the structure of the connecting portion 120.

By the way, in the present embodiment, the inner tip 130 is provided inside the tip end side of the cylinder 102. The inner tip 130 is, like the above-mentioned heavenly tip 110, formed into a curved and thin plate shape by a sintered body of metal powder containing diamond, and is provided inside the cylinder 102 by a method such as brazing. There is. The curved surface has a shape along the inner diameter of the cylinder 102, and the degree thereof is slight. In the illustrated example, the inner chip 130 is provided between the upper field chips 110, and the inner chips 130 are provided downward from the tip end position of the cylinder 102. The distance between the upper field chips 110 and the width dimension of the inner chip 130. Are almost the same. Thus, the heavenly chips 110 and the inner chips 130 are alternately arranged. In addition, as shown in FIG. 1B, the inner surface 130S of the inner tip 130 is higher than the inner side surface 110S of the top chip 110 in the radial direction of the cylinder 102. In other words, when the inner space of the cylinder 102 is viewed in the radial direction, the distance between the inner chips 130 is smaller than the distance between the heavens chips 110.

Next, the operation of this embodiment will be described with reference to FIG. Similar to the background art described above, when forming a through hole in the fume tube 20, the tip of the core drill bit 100 is applied to the hole-drilled portion of the fume tube 20 and rotationally driven by a motor or the like. Then, cutting is performed by the overhead chip 110 as shown in FIG. As the cutting progresses and the top chip 110 penetrates the fume tube 20, the result becomes as shown in FIG. Also in this embodiment, as shown in FIG. 4(B), when the corners of the top end of the heavenly chip 110 are removed due to wear and become round, the diameter of the surface side of the cut cylindrical core 22 becomes smaller. It is larger than the inner diameter of the cylinder 102 (see 22H). According to the above-mentioned conventional technique, when the large diameter portion 22H enters the cylinder 102, the large diameter portion 22H is caught in the cylinder and cannot be removed.

However, in this embodiment, the side surface of the core 22 is cut by the inner tip 130, and the diameter of the core 22 is smaller than that of the background art described above. Therefore, even if the core 22 tries to enter the cylinder 102, the core 22 is caught by the inner tip 130, and the core 22 does not enter the cylinder 102.

As described above, according to the present embodiment, since the core drill bit 100 is provided with the inner chip 130 inside the cylinder 102 in addition to the ceiling insert 110, the core 22 after cutting is placed inside the cylinder 102. The core 22 in the cylinder 102 can be easily taken out without getting in and getting caught, and the workability is improved.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIG. In the above-described embodiment, as shown in FIG. 1A, the space between the heavenly chips 110 and the width of the inner chip 130 are the same, but the inner chip 132 of FIG. The width is narrower than the interval between the chips 110. In the above-described embodiment, the inner chips 130 are provided between the heavenly chips 110, but in the example of FIG. 3B, one inner chip 132 is provided for every two heavenly chips 110. As shown in these examples, if it is possible to prevent the core 22 after cutting from entering the cylinder 102 and being caught therein, the number, shape, and arrangement of the inner chips 130 may be appropriately changed.

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. For example, the following are also included.
(1) The shapes and dimensions shown in the above embodiment are examples, and may be appropriately changed as necessary. The number of mounted top chips and inner chips and the intervals between them may also be appropriately set as necessary.
(2) Diamond chips are generally used as the ceiling chips and the inner chips shown in the above-mentioned examples, but various known chips used for cutting reinforced concrete can be used.
(3) In the above embodiment, the case of drilling holes in reinforced concrete has been described as an example, but the core drill bit of the present invention is applicable to various types of cutting.

According to the present invention, in addition to the heavenly chip, the inner chip is provided inside the cylinder, so the core after cutting does not get caught in the cylinder and is easily caught. You can take it out. Therefore, it is possible to improve workability, and it is suitable for drilling a fume tube.

10: Cylinder 12: Diamond tip 20: Fume tube 22: Core 100: Core drill bit 102: Cylinder 110: Tenba tip (diamond tip)
110S: inner side surface 120: connecting portion 122: expanded diameter portion 124: drive shaft 126: connecting pin 130: inner tip 130S: inner surface 132: inner tip

Claims (5)

A core drill bit in which a plurality of heavenly chips for cutting an object are provided at predetermined intervals at the tip of a cylinder,
A core drill bit, characterized in that a plurality of inner tips are provided inside the tip of the cylinder. The core drill bit according to claim 1, wherein a surface position of the inner tip is higher than an inner surface position of the heavenly tip inside the cylinder. The core drill bit according to claim 1 or 2, wherein the inner tip is provided inside a portion of the tip of the cylinder sandwiched by the heavenly tip, or provided at regular intervals. .. The core drill bit according to any one of claims 1 to 3, wherein the top chip and the inner chip are brazed to the cylinder. The core drill bit according to any one of claims 1 to 4, characterized in that a connecting tool with a rotation driving means is provided at a rear end of the cylinder.

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