JPH0726106U - Core bit - Google Patents

Abstract

(57) [Summary] [Purpose] To find a means that can effectively discharge the chips generated during the perforation of pebbles, reinforcing bars, etc. with a relatively simple structure. [Structure] In a core bit in which a segment chip 2 is fixed in the circumferential direction of the tip of a cylindrical base metal 1, a through hole 3 for discharging chips is formed in a peripheral wall of the cylindrical base metal. The chips, which are generated during drilling and cause clogging, are taken into the through holes 3 formed in the peripheral wall of the base metal 1 by rotating the core bit, and the cleaning water or cooling gas is efficiently transferred to the outer peripheral surface of the base metal. Will also be supplied.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a core bit used for perforating reinforced concrete, blocks, gypsum board, reinforced foam concrete, and the like.

[0002]

[Prior art]

 Conventionally, as such a core bit, one in which a segment tip is fixed in the circumferential direction of the tip of a cylindrical base metal is known, and by rotating this core bit, a circular opening can be formed in a concrete structure or the like. it can.

In recent years, in such core bits, for example, in Japanese Utility Model Laid-Open No. 4-2562, Japanese Utility Model Laid-Open No. 4-89614, and Japanese Utility Model Laid-Open No. 1-95304, the withdrawability from the object to be drilled and the perforation property are improved. A structure aimed at is proposed.

In Japanese Utility Model Laid-Open No. 4-2562, among diamond tips that are intermittently fixed to the tip of a cylindrical base metal, some diamond tips are arranged to have an inner diameter substantially equal to the inner diameter of the base metal. In Japanese Utility Model Laid-Open No. 4-89614, a core bit has an arrangement inner diameter of a part of a diamond tip substantially equal to an inner diameter of a base metal, and further an arrangement outer diameter of another diamond chip equal to an outer diameter of the base metal. The core bit is described in Japanese Utility Model Laid-Open No. 1-95304, and a diamond bit fixed to the tip of a base metal is composed of a chip slightly protruding from the inner surface of the base metal and a chip not protruding from the inner surface of the base metal. It is said that by adopting such a chip structure, it is possible to improve the drawability after perforation without causing clogging.

[0005]

[Problems to be solved by the device]

 However, in the above-mentioned core bit, when a small chip is bitten, the core bit can be extracted from the hole, but the chip remains in the groove. In many cases, chips that are larger than the gap between the bit and the object to be drilled are generally generated.The above bits are not effective enough to prevent chips from getting caught in pebbles, rebar, etc. In this case, the rotation of the core bit may stop and drilling work may not be possible.

Further, in recent years, as represented by Japanese Utility Model Laid-Open No. 63-193608, for example, a base metal main body has a double structure and an introduction passage for cooling gas or the like is provided, and compressed air, nitrogen gas, etc. are introduced from the introduction passage. A so-called dry core bit has been developed that supplies cooling gas to the cutting point and does not require cooling water.

In such a dry-type core bit, chip discharge is more problematic than in the above-described core bit using cooling water, but in the present situation, no promising technology has been established yet.

Therefore, the problem to be solved in the present invention is to find a means capable of effectively discharging the chips generated at the time of boring a small stone piece, a reinforcing bar piece or the like with a relatively simple structure.

[0009]

[Means for Solving the Problems]

 As a result of various studies on the biting that occurs during perforation, the present inventor has found that the cause of the trouble caused by biting is mainly due to chips that are harder than the chips generated during perforation. The present invention has been completed based on the knowledge.

That is, according to the present invention, in a core bit in which a segment tip is fixed in the circumferential direction of the tip of a cylindrical base metal, a circular or elliptical through hole for discharging chips is formed in the peripheral wall of the cylindrical base metal. It is characterized by

Here, the through hole may be circular and have an inner diameter in the range of 5 to 25 mm, or may be formed at least 5 mm or more from the tip end of the cylindrical base metal toward the base end. .

If the inner diameter of the circular through hole is less than 5 mm, the chip discharging effect is poor, and if it exceeds 25 mm, the strength of the base metal is reduced, which may cause deformation during use. In addition, the strength of the tip of the base metal can be particularly maintained by separating it from the tip of the cylindrical base metal by at least 5 mm or more.

Further, by forming the through hole for discharging chips from the tip of the cylindrical base metal continuously, the rotation speed of the core bit increases the speed of discharging chips.

[0014]

[Action]

 The chips that are generated during drilling and cause clogging are taken into the through holes formed in the peripheral wall of the base metal by rotating the core bit, and cleaning water or cooling gas is efficiently applied to the outer peripheral surface of the base metal. Will also be supplied.

[0015]

【Example】

 The features of the present invention will be specifically described below based on the embodiments shown in the drawings.

FIG. 1 is a perspective view showing a diamond core bit according to a first embodiment of the present invention.

In the figure, reference numeral 1 denotes a cylindrical base metal having a mounting portion 1a for mounting on a punching machine formed at an upper end thereof, and a diamond segment tip 2 is fixed to a tip end portion thereof at regular intervals in a circumferential direction. Has been done. Further, a circular through hole 3 is formed at one location on the peripheral wall near the tip of the base metal 1. This through hole 3 is for discharging chips generated during drilling, and its inner diameter is preferably in the range of 5 to 25 mm from the viewpoint of the chip discharging effect and the strength of the base metal. Further, the formation position of the through hole 3 is separated from the tip of the cylindrical base metal 1 by at least 5 mm or more from the standpoint of strength of the base metal.

FIG. 2 is a vertical cross-sectional view for explaining the operation of the diamond core bit shown in FIG. 1. As shown in FIG. 2, the chips K of the reinforcing bar pieces and the like generated by perforation are generated by the rotation of the diamond core bit. Since it does not fall into the through holes 3 provided in the peripheral wall of the base metal 1 and remain in the perforations, it is possible to effectively prevent clogging due to the chips K. In addition, even if biting occurs, the core bit can be rotated with a wrench to drop chips such as rebar pieces into the through hole 3, and the core bit can be easily pulled up, and at the same time, the chip K in the through hole 3 is also discharged to the outside. be able to.

FIG. 3 is a perspective view showing another embodiment of the core bit. In this embodiment, the through hole 5 has an elliptical shape. Such an elliptical shape is particularly effective when the chips K generated at the time of perforation are long-sided, as compared with the circular through-hole.

FIG. 4 is a perspective view showing still another embodiment of the core bit, and in this embodiment, the through hole 6 has a shape continuous from the tip of the cylindrical base metal. With such a shape, it is particularly effective for continuous chips.

In the above embodiments, the diamond core bits 2 are arranged at the tip of the base metal 1 at intervals, but the present invention can also be applied to the one in which a so-called straight type segment tip is fixed. it can. Further, it is of course applicable to the dry type core bit described in the prior art.

[0022]

[Effect of device]

 The present invention has the following effects.

(1) Chips are taken into the through holes formed in the peripheral wall of the base metal, and cleaning water or cooling gas is efficiently supplied also to the outer peripheral surface of the base metal, which is effective with a simple structure. It is possible to prevent clogging.

(2) When taking out the work material remaining in the core bit after drilling, by pressing a chisel or an iron rod into the through hole and hitting it with a hammer, the remaining core can be easily removed. .

[Brief description of drawings]

FIG. 1 is a perspective view showing a diamond core bit according to a first embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view for explaining the operation of the diamond core bit shown in FIG.

FIG. 3 is a perspective view showing another embodiment of the core bit.

FIG. 4 is a perspective view showing still another embodiment of the core bit.

[Explanation of symbols]

 1 base metal 1a mounting part 2 diamond tip 3, 5, 6 through hole

Claims (4)

[Scope of utility model registration request] 1. A core bit in which a segment chip is fixed in the circumferential direction of the tip of a cylindrical base metal, wherein a through hole for discharging chips is formed in the peripheral wall of the cylindrical base metal. 2. The through hole is circular and has an inner diameter of 5
The core bit according to claim 1, wherein the core bit is in the range of 25 mm. 3. The core bit according to claim 1, wherein the through hole has a shape continuous from the tip of the cylindrical base metal. 4. The core bit according to claim 1, wherein the through hole is formed at least 5 mm or more from the tip end of the cylindrical base metal toward the base end.