JPH0242795Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an earth auger used for constructing foundation piles, and particularly to an earth auger having a tapered shaft head at its tip.

(Prior art and its problems) This type of earth auger is disclosed in Japanese Patent Publication No. 57-44794. In other words, according to this publication, the auger head consists of a tapered shaft portion and a screw protruding spirally from the circumferential surface of this shaft portion, and this tapered shaft portion allows the soil excavated during excavation to be The soil is pushed outward and compressed to minimize or eliminate soil removal, thereby greatly reducing soil removal work. However, such an auger head has the problem of being difficult and expensive to manufacture.

(Technical means for solving the problems) In view of the above problems, the present invention provides an earth auger that is easy to manufacture and can be made at low cost. A plurality of substantially sector-shaped block pieces 3a ₁ , 3b ₁ , 3a ₂ , 3 whose side surfaces engage with the circumferential surface of the auger shaft and whose outer surfaces form inclined surfaces and whose outer diameters sequentially vary.
b ₂ , 3a ₃ , 3b ₃ , and 3a ₄ are continuously fitted and arranged along the spiral groove 4 of the screw 2, and bolts 5 are secured to the auger shaft 1 to form a tapered shaft head 3. It is characterized by the fact that it has been formed.

(Example) Examples of the present invention will be described below based on the drawings.

FIG. 1 shows an earth auger according to an embodiment of the present invention. In this figure, 1 is a hollow auger shaft, and a screw 2 is provided along its entire length. Reference numeral 3 denotes a tapered shaft head formed at the tip of the auger shaft 1, and each of the shaft heads 3 has an inner surface that engages with the outer circumferential surface of the auger shaft 1, and an outer circumferential surface that is a downwardly inclined surface. A plurality of substantially sector-shaped block pieces 3a ₁ , 3b ₁ , 3a ₂ , 3b ₂ , 3a ₃ , 3b ₃ , which have sequentially different outer diameters and have different outer diameters.
3a and ₄ are continuously fitted and arranged along the spiral groove 4 of the screw 2, and the bolt 5 is connected to the auger shaft 1.
formed by stopping. Reference numeral 6 denotes an auger head, the upper end of which has a mounting shaft 6a fitted into the tip of the auger shaft 1, and a pin hole 7a connected to the shaft head 3 and the auger shaft 1 and the mounting shaft 6.
It is attached by a pin (not shown) that is engaged across a pin hole 7b provided in a.

The block pieces 3a ₁ , 3b ₁ , . . . 3a ₄ are made of cast iron or steel, and these are made up of three pairs of half-split bodies formed for each pitch of the screw 2 and a pair of halves. (Block piece 3 at the tip)
a ₄ ), and among these, the uppermost block pieces 3a ₁ and 3b ₁ consisting of a pair of half-pieces are shown in FIG. As is clear from FIG. 2, these block pieces 3a ₁ and 3b ₁ are formed in a downwardly inclined shape with inner surfaces 8a and 8b formed to engage with the outer circumferential surface of the auger shaft 1 by half a circumference, respectively. The upper and lower end surfaces of these block pieces 3a ₁ and 3b ₁ are respectively formed to engage with the upper and lower surfaces of the screw 2. . When installing, these block pieces 3a ₁ and 3b ₁ are fitted into the spiral groove 4 of the screw 2 and the inner surfaces 8a and 8 are fitted.
With b engaged with the auger shaft 1, insert the bolt 5 through the bolt hole 10 of each block piece, screw it into the threaded hole (not shown) of the auger shaft 1 previously provided at a predetermined position, and fasten and secure. do it.

The block pieces 3a ₁ and 3b ₁ form a pair of halves, and each of these block pieces is further divided into two to form a block piece 3a ₁ consisting of four halves as shown in FIG. '3a ₁ '3b ₁ '3b ₁ ' can also be used.

In using the earth auger having the above-described construction, the auger head 6 is attached to the tip of the auger shaft 1, and the auger shaft 1 is rotated by the auger drive device to excavate underground. During this drilling, the soil excavated by the auger head 6 is pulled up slightly by the screw 2 at the tip of the auger shaft 1, and is moved outward in a radial direction by the shaft head 3, which is tapered at the end. The material is expanded and compressed to form a firm peripheral wall surface of the hole.

4 to 6 show other embodiments of the present invention. First, according to the embodiment shown in FIG.
While the tapered shaft head 3 in the previous embodiment shown in the figures is provided directly on the tip of one auger shaft 1, the tapered shaft head 13 in this embodiment of FIG. The shaft head 13 is formed on a short auger shaft 11' with a screw 12' attached to the tip of the auger shaft 11 with Block pieces 13a ₁ , 13b ₁ , 13
This is done by continuously combining a ₂ , 13b ₂ , 13a ₃ , 13b ₃ along the spiral groove. 15 in FIG. 4 indicates a bolt. FIG. 5 shows an auger shaft 21 having a screw 22 only at its tip, and a tapered shaft head 23 formed at the tip where the screw 22 is located. Shaft head 1 in the diagram
Similarly to 3, block pieces 23a ₁ , 23b ₁ , 23a ₂ ,
It consists of 23b ₂ , 23a ₃ , and 23b ₃ . In FIG. 5, reference numeral 25 indicates a bolt, and reference numeral 26 indicates a screw hole provided in the auger shaft 21. Furthermore, FIG. 6 shows a short auger shaft 31 with a screw 32 similar to the auger shaft 11' with a screw in the embodiment shown in FIG. This is an example of an earth auger that is integrally connected.

(Effect of the invention) The earth auger of the present invention has a plurality of block pieces that are successively fitted and arranged along the spiral groove of the screw and bolted to the auger shaft, thereby creating a tapered shaft head. Because the shaft head is formed, it is much easier to manufacture than conventional ones, and costs can be reduced. On the other hand, the shaft head can be easily disassembled and removed by removing the bolts. In the event of damage, at least the shaft head only needs to be replaced, and if the shaft head is removed, it can be used as a normal screw auger.

[Brief explanation of the drawing]

Fig. 1 is an elevational view of the main part of an earth auger showing an embodiment of the present invention, Fig. 2 is an exploded perspective view of a pair of two-part block pieces forming the tapered shaft head in Fig. FIG. 3 is an exploded perspective view similar to FIG. 2 illustrating a four-part block piece, and FIGS. 4, 5, and 6 are elevational views showing various other embodiments of the present invention. 1, 11, 11', 21, 31...auger shaft,
2, 12, 12', 22, 32...screw,
3, 13, 23, 33...Tapered shaft head, 3a ₁ to 3a ₄ , 3b ₁ to 3b ₃ , 3a ₁ ′, 3b ₁ ′,
13a ₁ to 13a ₃ , 13b ₁ to 13b ₃ , 23a ₁ to 23
a ₃ , 23b ₁ to 23b ₃ ... block piece, 4 ... spiral groove, 5, 15, 25 ... bolt.

Claims (1)

[Scope of utility model registration request] A plurality of substantially fan-shaped block pieces in cross section, each of which has an inner surface that engages with the circumferential surface of the auger shaft and whose outer surface forms an inclined surface and whose outer diameters are successively different, are continuously inserted along the spiral groove of the screw. What is claimed is: 1. An earth auger characterized in that the earth auger is fitted into the auger shaft and bolted to the auger shaft to form a tapered shaft head.