JPH0554696U - bit - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the biting property of the cutting edge for a long period of time. [Structure] An insert tip 3 having a band-shaped edge 6 is embedded in a tip end head portion 2 of a bit body 1. The strip-shaped edge 6 is a truncated cone shape that a basic, apex angle theta ₁ of the conical surface and is formed by the apex angle theta ₂ by the inclined plane 5. When implanting the insert chip 3 having the strip-shaped edge 6 in the bit body 1, the strip-shaped edge 6 is located in the radial direction of the bit body 1 to improve the biting property.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to an inner type bit, a ring type bit and the like, and particularly, the biting property thereof is improved over a long period of time.

[0002]

[Prior Art]

 Conventionally, as this kind of bit, a button bit in which the protruding end of the insert tip has a spherical shape, a conical bit in a conical shape, and the like are known.

[0003]

[Problems to be solved by the device]

 However, the button bit does not have a good biting property at the cutting edge, and the konica rub bit has a good biting property at the initial stage, but has a problem that it wears quickly and the excavation speed drops sharply.

In view of the above, the present invention seeks to provide a bit having a cutting edge shape with improved biting property and wear resistance.

[0005]

[Means for Solving the Problems]

The present invention has been made in view of the above point, and the excavating cutting edge of the insert tip has a frustoconical shape as a basic shape, and the apex angle of the conical surface is 90 ° to the circumferential side surface with respect to the conical surface. By forming an inclined plane having an apex angle θ ₂ larger than θ ₁ , a band-shaped edge is formed at the truncated portion. When the insert tip is implanted in the bit body, the strip-shaped edge is located in the radial direction of the bit body.

[0006]

[Action]

 In the bit of the present invention, the band-shaped edge forming the cutting edge is located in the radial direction of the bit body. Therefore, the excavation blade edge has a good bite property and the edge length is large, so that it has excellent wear resistance.

[0007]

【Example】

 An embodiment of the bit of the present invention will be described below with reference to the drawings.

In FIGS. 1 and 2, reference numeral 1 denotes a cylindrical bit body, and an insert tip 3 made of cemented carbide is implanted in a tip head portion 2 thereof. The projecting end of the insert tip 3 constitutes the excavating blade edge 4.

As clearly shown in FIGS. 3A to 3C, the excavating cutting edge 4 has a frustoconical shape as a basic shape, and has a 90 ° circumferential side surface with respect to the conical surface. Shows that the inclined plane 5 having the apex angle θ ₂ larger than the apex angle θ ₁ of the conical surface is formed. Therefore, the strip-shaped edge 6 is formed in the truncated portion.

When the insert tip 3 having such a cutting edge 4 is implanted in the bit body 1, the strip-shaped edges 6 are located in the radial direction of the bit body 1.

Further, the bit body 1 is provided with a powder discharge groove 7 on the outer peripheral portion thereof, and a drain port 8 is formed in the central portion thereof. The bit shown in FIG. 4 is such that a groove 9 is added to the central drainage port 8.

Furthermore, in FIG. 5, down-the-hole bits are applied, and in FIG. 6, ring bits are applied respectively.

[0013]

[Effect of the device]

 In the present invention, as described above, the band-shaped edge 6 is formed on the excavating cutting edge 4 of the insert tip 3 to be implanted in the bit body 1, and the band-shaped edge 6 is positioned in the radiation direction of the bit body 1. Is. Therefore, the bit of the present invention has the advantages that, due to the existence of the band-shaped edge 6, the biting property and the wear resistance are improved, and the excavation performance and the life can be expected to be extended.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a bit of the present invention.

FIG. 2 is a perspective view.

FIG. 3 is a view showing an insert tip, (a) is a front view,
(B) is a side view and (c) is a plan view.

FIG. 4 is a perspective view showing a modified example of the inner bit.

FIG. 5 is a perspective view showing a modified example applied to a down the hole bit.

FIG. 6 is a perspective view showing a modified example applied to a ring bit.

[Explanation of symbols]

 1 bit main body 2 tip head 3 insert tip 4 excavation edge 5 inclined plane 6 strip edge 7 milling dust discharge groove 8 drainage port 9 groove

Claims (1)

[Scope of utility model registration request] 1. A bit in which an insert tip 3 made of cemented carbide is implanted in a tip head portion 2 of a bit body 1 and a protruding edge of the insert tip 3 constitutes an excavating edge 4, wherein the excavating edge 4 is The basic shape is a truncated cone, and the inclined flat surface 5 having an apex angle θ ₂ larger than the apex angle θ _{1 of the} conical surface is formed on the circumferential side surface of 90 ° with respect to the conical surface. , The strip-shaped edge 6 is formed on the truncated portion, and when the strip-shaped edge 6 is implanted in the bit body 1, the strip-shaped edge 6 is positioned in the radial direction of the bit body. bit.