JPH0133633B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a pawl attached to the head of an earth auger drill, and more specifically, the present invention relates to a pawl that is attached to the head of an earth auger drill. Concerning shape.

(Prior Art) FIG. 6 is a diagram showing a conventional earth auger drill head with claws 1A and 1B attached, in which two screw plates 3A and 3 are attached to a head shaft (casing) 2.
Weld B to the lower ends of these screw plates 3A and 3B, one or more each (two in the illustrated example).
The claws 1A and 1B are arranged and welded in the inner and outer directions. These claws 1A, 1B are shown in FIGS. 7 and 8.
As shown in the figure, cemented carbide is welded or brazed to the prismatic tip 1a and the outer surface 1b, which are sharply formed, and the tip 1a is attached to the upper surface so that the width gradually becomes smaller. An inclined surface 1c is formed.

In such a conventional structure, as shown in FIG. 8, the tips of the outer claws 1A protrude outward from the rotation locus 4 of the outer surface 1b that accompanies the rotation of the drill. As the period of use progresses, the outer part of the tip 1a wears out in a triangular shape as shown by the shaded area 5, and every 2 to 3 months the head is transported from the site to the factory to remove the old nail 1A. The screw plates 3A and 3B have to be melt-cut and new claws 1A are welded to the screw plates 3A and 3B. This requires replacement frequently and is expensive as it uses a lot of cemented carbide. The problem is that it is uneconomical.

Therefore, the inventor of the present invention
As proposed in No. 59-26178 and Utility Model Application No. 59-30077, the shape of the claws 6A and 6B is such that both the inner and outer surfaces or the outer surface thereof has an arc shape along the rotation locus 4 shown in FIG. We have already developed something shaped like this. With this shape, as the usage period passes, the claw 6A will wear from the outer surface 6a, and the degree of wear of the tip 6b, which plays the role of biting during hole drilling, will decrease, reducing the wear. Experiments have shown that when this structure is adopted, the lifespan can be extended by about four times compared to conventional methods.

However, if these claws are made to have a simple square or rectangular cross-sectional shape when cut in the transverse direction, it is difficult to form them without casting, and if by forging, a complex mold with a composite shape is required. It cannot be molded without it.

(Problems to be Solved by the Invention) The present invention has been made in view of the above-mentioned points, and it is possible to reduce the wear due to the passage of a period of use, reduce the frequency of replacement, and to make it easier and cheaper. The purpose of the present invention is to provide a claw for a drill head that can be manufactured.

(Means for Solving the Problems) In the present invention, the shape of the claw is such that when the claw is installed, the outer surface of the claw has an arc shape along the entire length along the rotation locus accompanying the rotation of the drill, and the shape is vertical. It is characterized by being formed in a twisted shape so that the tips of the claws are horizontal, and the cross-sectional shape cut in the transverse direction is tapered so that the width becomes narrower toward the bottom. do.

(Function) With such a shape of the claw, when forging is used, die cutting can be easily performed, and the claw can be manufactured by forging using a die having a simple shape.

(Example) Figures 1 and 2 show an embodiment of the claw of the present invention. As shown in the figures, the cross-sectional shape of the claw when cut in the transverse direction is tapered so that the width becomes narrower toward the bottom. It is formed into a shape. Further, as shown in FIG. 3, the overall shape of the claw 8 in this embodiment is not only curved in an arc along the side surface 7A of the excavated hole, but also has a sharp tip. The inner side 8b of 8a is twisted so that it is slightly lowered.

As mentioned above, if the claw 8 is shaped so that its bottom is narrow, the shape of the lower mold 10 having the groove 10a corresponding to the upper surface shape of the claw and the shape of the claw material 8A will be changed as shown in FIG. The claw material 8A is formed by forging by setting the material between it and an upper mold 9 having a corresponding recess 9a and compressing it or striking it with a hammer, and then lowering the upper mold 9 together with the material 8A. It can be removed from the mold 10 by hooking the burr 8e on a hook (not shown) and pulling it out from the recess 9a of the upper mold 9. The taken-out material 8A has its peripheral burr 8e removed and the tip 8a
The product is manufactured by welding cemented carbide to necessary parts such as the upper corner of the outer surface 8 and the like.

Further, in this embodiment, since the claw 8 has a twisted shape, when the claw is attached to the lower end of the screw plate 3A (3B) by welding, as shown in FIG. 8a can be made horizontal, thereby making the tip 8 of the claw 8
a can be made to bite into the bottom surface 7 of the excavated hole as a whole, so that wear does not concentrate on the outside of the tip 8a, and furthermore, the screw plate 3A (3
B), as shown in FIG. 3A (3B), that is, when the tip is tilted downward, the outer surface of the claw (the upper part of the tip of the claw protrudes outward), so the entire outer surface is attached to the wall of the excavation hole. 7A, it is possible to prevent the occurrence of a phenomenon in which the outer upper part of the tip portion 8a wears out, which would occur if the tip portion 8a were simply curved into an arc. According to experiments, in the case of the structure of this example, compared to conventional nails, the nail
It was able to last twice as long.

There are various twist structures when carrying out the present invention. For example, it is also possible to form three or more discontinuous surfaces on the upper and lower surfaces of the nail so that the twist is formed as a whole. .

(Effects of the Invention) According to the present invention, the shape of the pawl is formed so that the outer surface of the pawl forms an arc along the rotation locus accompanying the rotation of the drill when the pawl is attached. Prevents uneven wear from front to back,
In addition, since the outer surface of the claw is vertical, it is possible to prevent uneven wear in the vertical direction of the claw, and since the tip of the claw is formed horizontally, it is also possible to prevent uneven wear on the tip of the claw. This makes it possible to extend the lifespan of the nails far more than that of conventional nails, eliminating wasted materials, creating economical nails, and reducing the frequency of nail replacement, making it easier for the user to use the nails. It can provide nails that are extremely beneficial to people.

Furthermore, unlike casting, the claw of the present invention does not require a large-scale heating device or heating time for materials, and can be manufactured easily and inexpensively by forging using a simple die. In addition, when a claw formed in the shape of the present invention is used in the head at the lower end of a drill, it becomes possible to excavate rock, which was previously difficult, and rock excavation can be performed approximately 4.5 times more efficiently than before. Confirmed.

[Brief explanation of drawings]

Figures 1A, B, and C are a side view, plan view, and front view showing one embodiment of the claw of the present invention, respectively, and Figures 2A, B, and C are EE and F of Figure 1B, respectively.
F, GG sectional view, Fig. 3 is a front view showing the claw of this embodiment in the attached state, Fig. 4 is a sectional view showing the molding method of this embodiment, and Fig. 5 is the mounted state of the claw of this embodiment. Fig. 6 is a front view showing the head with a conventional claw attached, Fig. 7 is a perspective view showing the outer claw, Fig. 8 is a partial plan cross-sectional view of Fig. 6, FIG. 9 is a plan view illustrating problems with conventional nails. 2...Head shaft, 3A, 3B...Screw plate, 4...Rotation locus, 8...Claw.

Claims (1)

[Claims] 1. For the claws attached to the head of the earth auger drill, the shape of the claws is such that when the claws are installed, the outer surface of the claws has an arc shape along the entire length along the rotation locus accompanying the rotation of the drill, and has a vertical surface. A drill characterized in that the tip of the claw is twisted so that it is horizontal, and the cross-sectional shape when cut in the transverse direction is tapered so that the width becomes narrower toward the bottom. Nails for the head.