JPH0522683U - Cutting bit - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent wear of the excavation head 2 of the cutter bit. [Construction] The cutter bit 1 comprises an excavation head 2 and a shank 3, and the excavation head 2 is provided with an excavation blade tip 4 made of cemented carbide and a central tip 5 for wear prevention. The central tip is on the flank 6 side, is substantially orthogonal to the central back portion of the excavating blade tip 4, and reaches the rear of the flank 6. The rake face 7 and the flank face 6 of the excavation head 2 are often V-shaped protrusions, and a side tip 9 made of a cemented carbide is provided on the flank face 6 side of the excavation blade tip 4 on the flank face 6 side. If it is made to be substantially orthogonal to the back, wear prevention will function more reliably. The cutting blade tip 4 is mounted by brazing in the mounting groove 8 formed by the flank surface 6 and the rake surface 7 in the direction of the bisector of the apex angle. It is also possible to braze into the mounting recess 10 of the rake face 7.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a cutter bit mounted on a tunnel excavator or the like, and particularly to prevent wear of the excavation head of the cutter bit.

[0002]

[Prior Art]

 Conventionally, this type of cutter bit has an excavating blade made of cemented carbide brazed to the excavating head. Then, the excavating blade performs the excavating action while pushing away the earth and sand. At that time, the wear of the steel portion progresses, and especially when the excavator reverses, the wear of the steel portion progresses further because the earth and sand are scraped from the rear end. For this reason, the steel portion of the excavation head is subjected to welding hardening overlay, or a spare tip is provided behind the excavation blade as in Japanese Utility Model Publication 60-19199.

[0003]

[Problems to be solved by the device]

 However, in the case of welding hardfacing, the wear resistance of the hardfacing is limited, and in the case of a backup tip at the rear, there is the problem that the wear of the steel part behind the drilling blade cannot be prevented. It was

In view of the above, the present invention seeks to provide a cutter bit capable of reducing wear of the excavating head and maintaining an effective excavating function for a long period of time.

[0005]

[Means for Solving the Problems]

 The present invention has been made in view of the above-mentioned points, and on the flank side of the excavating blade provided on the excavating head, at least in the center back portion, it extends to the rear of the flank substantially orthogonal to the excavating blade. It is configured to have a central tip made of cemented carbide for wear prevention. In this case, the digging blade is located in the mounting groove provided in the direction of the bisector of the apex angle by the rake face and the flank, or in the mounting recess on the rake face side. The flank of the excavation head should be a V-shaped protrusion with a convex center, and both sides of the flank should be equipped with cemented carbide side tips to prevent wear more reliably. Is.

[0006]

[Action]

 In the cutter bit of the present invention, not only the excavating blade but also the central chip and the side tip are exposed on the flank of the excavating head, so that the wear of the steel portion is reduced. In particular, it has the function of reducing the progress of wear due to the ingestion of earth and sand when the excavator is reversed.

[0007]

【Example】

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

1 to 3, reference numeral 1 denotes a cutter bit composed of a drill head 2 and a shank 3, and the drill head 2 has a drill blade tip 4 and a central chip 5 made of cemented carbide. It is equipped. In this case, the flank 6 of the excavation head 2 has a V-shaped roof shape with a convex center. Therefore, the digging blade tip 4 is brazed in the mounting groove 8 provided in the direction of the approximately bisector of the apex angle by the flank surface 6 and the rake surface 7. Further, the central tip 5 for wear prevention is on the flank 6 and extends substantially orthogonal to the central back portion of the cutting blade tip 4 and reaches the rear of the flank 6. The contact relationship with the digging blade tip 4 is not limited to the case shown in FIG. 2, but can be changed as shown in FIGS. 4 and 5.

The cutter bit configured as described above is attached to an excavator (not shown) using the attachment holes 3 a provided in the shank 3. In this attachment, two cutter bits are usually attached so that the excavating blade tip 4 is located on the left and right, and forward and reverse rotation excavation is possible.

FIG. 6 shows a cutter bit 1 according to another embodiment, in which, besides the central tip 5, side tips 9 made of cemented carbide are provided on both sides of the V-shaped protrusions. Is arranged substantially orthogonally behind the drilling blade tip 4. This results in less exposed surface of the steel and better protection against wear.

Further, FIGS. 7 and 8 show another embodiment, in which the drilling blade tip 4 is located in a mounting recess 10 provided on the rake face 7 side. In this case, the flank 6 is provided with the central tip 5, and the flank 6 and the rake face 7 are flat.

[0012]

[Effect of the device]

 As described above, according to the present invention, the central tip 5 for preventing wear, and the side tip 9 if necessary, are located on the flank 6 side of the excavation head 2, so that the wear of the steel portion is prevented. In particular, the progress of wear due to the ingestion of earth and sand during reverse rotation is reduced. Therefore, it is expected that the drilling efficiency and tool life will be extended.

[Brief description of drawings]

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

FIG. 2 is a plan view.

FIG. 3 is a side view.

FIG. 4 is a cross-sectional view showing a modified example.

FIG. 5 is a cross-sectional view showing another modification.

FIG. 6 is a plan view showing another embodiment of the cutter bit of the present invention.

FIG. 7 is a front view showing another embodiment of the cutter bit of the present invention.

FIG. 8 is a plan view.

[Explanation of symbols]

 1 Cutter Bit 2 Excavation Head 3 Shank 4 Excavation Blade Tip 5 Center Tip 6 Relief Surface 7 Rake Face 8 Mounting Groove 9 Side Tip 10 Mounting Recess

Claims (3)

[Scope of utility model registration request] 1. A cutter bit in which a cutting blade tip 4 made of a cemented carbide is provided at the tip of a drilling head 2, wherein the cutting blade tip 4 has an apex angle substantially defined by a rake face 7 and a flank face 6. In the mounting groove 8 provided in the bisector direction, or in the mounting recess 8 on the rake face side 7 in which the length on the rake face 7 side is longer than the length on the flank face side,
Moreover, on the flank 6 side of the drilling blade tip 4, at least a central back portion is provided with a central tip 5 made of a cemented carbide for wear prevention that extends substantially orthogonal to the drilling blade tip 4 and reaches the rear of the flank 6. A cutter bit that is designed to be used. 2. The cutter bit according to claim 1, wherein the flank 6 of the excavation head 2 has a V-shaped projection shape having a convex center. 3. The V-shaped projection flank 6 according to claim 2 is provided on both sides of which the flank 6 is distributed so as to prevent wear from reaching the rear of the flank 6 substantially orthogonal to the drilling blade tip 4. A cutter bit with a side tip 9 made of hard alloy.