JP2020006670A - Bit for hammer drill - Google Patents

Abstract

To provide a bit for a hammer drill having a simple blade structure, in which the correction of the blade after use is easy to be performed, and initial performance can be maintained.SOLUTION: A bit for a hammer drill can maintain high performance over a long period by optimizing the blade edge angle of the bit for the hammer drill, and further, elongating a bit head for the hammer drill.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a tool used for drilling concrete.

  Conventionally, there is a hammer drill bit used for drilling various types of concrete, but there is no hammer drill bit that has a simple blade structure, makes it easy to modify the blade after use, and can maintain the initial performance for a long time. .

JP-A-10-369830 Japanese Patent Application No. 2001-55938 Japanese Patent Application No. 2004-511019

  It is often said that the hammer drill bit is made of cemented carbide for the head, so it is impossible to modify the blade.However, in recent years there is a high-performance diamond grindstone that can be set in a small grinder and the cemented carbide blade However, since it can be easily corrected, it is desired to realize a hammer drill bit having high drilling performance in consideration of blade correction.

  In order to achieve the above object, the present invention sets the inner angle of the front blade of the hammer drill bit head (1) to 60 ° to 65 ° (7), (8) from the hammer drill bit center line (6), respectively. ), The hammer drill bit head (1) the entire inner angle of the front blade is set to 120 ° to 130 °, and the inner angle of the hammer drill bit head (1) the side blade in the rotational direction plane. 20 ° to 25 ° (9) from the center line of the hammer drill bit (6) and 30 ° to 35 ° (10) from the center line of the hammer drill bit (6). The angle inside the entire blade on the side surface of the hammer drill bit head (1) is set to 50 ° to 60 °. In addition, the length of the hammer drill bit head (1) is set to about 1.5 times the diameter of the hammer drill bit head, and even if the worn edge is corrected, it can withstand long-term use while maintaining the initial performance. A hammer drill bit is realized.

  As described above, the hammer drill bit of the present invention exhibits a high level of performance in drilling concrete, and at the same time, is easy to use because the blade after use is easily corrected and can withstand long-term use.

The front view of the bit for hammer drills which shows embodiment of this invention. Side view of the same hammer drill bit Enlarged sectional view of the front of the hammer drill bit head Enlarged sectional view of the side of the head of the hammer drill bit

Embodiments for carrying out the invention

  Hereinafter, embodiments of the present invention will be described.

  The smaller the internal angle of the blade at the front of the head of the hammer drill bit, the sharper the tip of the blade, and the more stable the positioning of drilling in concrete. However, if it is too sharp, the depth at the center of the tip of the hole becomes large, and the driving strength of the outer cone anchor may decrease. From these facts, it is considered optimal to set the inner angle of the front face of the hammer drill bit head to 120 ° to 130 °.

  The smaller the inner angle of the side face of the head of the hammer drill bit, the sharper the tip of the blade, and the higher the ability to drill into concrete. However, if the edge is made too sharp, the blade edge may be damaged when it hits a hard aggregate such as a reinforcing bar inside the concrete at the time of drilling. From these facts, it is considered optimal to set the inner angle of the blade on the side surface of the head for the hammer drill to 50 ° to 60 °.

  Since the hammer drill bit is used for drilling concrete, even if a cemented carbide is used for the head, the cutting edge wears down with the progress of the drilling operation and the drilling ability decreases, so the cutting edge needs to be corrected. In recent years, there is a high-performance diamond grindstone that can be set in a small grinder, and even a cemented carbide blade can be easily corrected. From the above, even if the number of times of blade correction is increased, it is possible to withstand long-term use by extending the length of the hammer drill bit head. The optimal length of the hammer drill bit head is considered to be about 1.5 times the head diameter.

  As described above, the normal two-blade method is most suitable for easily correcting the cutting edge of the hammer drill bit with the diamond grindstone, and the three-flute delta method is extremely difficult. Further, there is a method of stabilizing the drilling position by providing a projection at the center of the cutting edge with a two-blade type hammer drill bit, but it is impossible and impractical to correct the cutting edge while leaving the projection.

Explanation of number

DESCRIPTION OF SYMBOLS 1 Hammer drill bit head 2 Carbide alloy part 3 Hammer drill bit main body 4 Chip discharge groove 5 Shank 6 Hammer drill bit center line 7 Cutting angle from hammer drill bit center line 8 From hammer drill bit center line 9 Angle of cut from hammer drill bit center line 10 Angle of cut from hammer drill bit center line

  In order to achieve the above object, the present invention sets the inner angle of the front blade of the hammer drill bit head (1) to 60 ° to 65 ° (7), (8) from the hammer drill bit center line (6), respectively. ), And the entire inner angle of the front blade of the hammer drill bit head (1) is set to 120 ° to 130 °, and the inner angle of the hammer drill bit head (1) side blade in the rotational direction plane. The hammer drill is set at 20 ° to 25 ° (9) from the center line of the hammer drill bit (6), and the inner angle of the blade on the other surface is set to 30 ° to 35 ° (10) from the center line of the hammer drill bit. The internal angle of the blade on the side surface of the tool bit head (1) is set to 50 ° to 60 °. Also, the length of the hammer drill bit head (1) is 1.5 times the diameter of the hammer drill bit head, so that even if the worn edge is modified, the hammer that can withstand long-term use while maintaining the initial performance. Realize a drill bit.

  Since the hammer drill bit is used for drilling concrete, even if a cemented carbide is used for the head, the cutting edge wears down with the progress of the drilling operation and the drilling ability decreases, so the cutting edge needs to be corrected. In recent years, there is a high-performance diamond grindstone that can be set in a small grinder, and even a cemented carbide blade can be easily corrected. From the above, even if the number of times of blade correction is increased, it is possible to withstand long-term use by extending the length of the hammer drill bit head. It is considered that the optimal length of the hammer drill bit head is 1.5 times the head diameter.

Claims (3)

  The inside angle of the front edge of the hammer drill bit head (1) is set to 60 ° to 65 ° (7) and (8) from the center line of the hammer drill bit (6), respectively, and the front edge of the head (1) is set. Hammer drill bit with an angle within the entire range of 120 ° to 130 °.   The inside angle of the blade on the side of the hammer drill bit head (1) is set to be 20 ° to 25 ° (9) from the center line of the hammer drill bit (6) in the rotational direction, and The angle is set to 30 ° to 35 ° (10) from the center line of the hammer drill bit (6), and the entire internal angle of the blade on the side surface of the head (1) is set to 50 ° to 60 °. Bit for hammer drill.   The hammer drill bit according to claim 1 or 2, wherein the length of the hammer drill bit head (1) is about 1.5 times the diameter of the hammer drill bit head (1). .

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