JPH07238785A - Head cutter for propulsion - Google Patents

Abstract

PURPOSE:To prevent damage to an auger screw by a method wherein the size of stones taken in is made equal to or less than a specific dimension with respect to the inner diameter of a cutter casing by causing a head cutter for propulsion to push aside stones larger than a predetermined dimension. CONSTITUTION:A helical protruding strip 31 of a cutter axis 9 and a cutter casing 35 rotate together with an auger screw 21 so that the strip 31 cuts into earth and sand to excavate it. Next, stones smaller than the pitch of the strip 31 are taken into the bottom of valley of the strip together with the earth so as to be carried by the screw 21 and discharged to the side of a starting shaft, wherein large stones 17 are pushed aside. The leading edge 37 of the casing 35 becomes parallel to the rearmost portion 31' of the strip 31 and the interval between the edge 37 and the portion 31' becomes nearly equal to the pitch of the strip 31, so that a stone 42 larger than the pitch of the strip 31 can not get into the casing 35 from the gap between the edge 37 and the portion 31'. The pitch of the strip 31 is made 1/3 or less of the inner diameter of the casing 35.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a propulsion head cutter in a propulsion device in which a vinyl chloride pipe or other pipe is buried in the ground without cutting the ground surface.

[0002]

2. Description of the Related Art In a conventional propulsion device, FIGS.
As shown in, a head cutter 5 for propulsion is attached to the front end of the shaft 3 of the auger screw 1. That is, the cutter shaft 9 is connected to the front end of the shaft 3 of the auger screw 1 (referred to as the left end in FIG. 2) via the connecting means 7, and the head cutter 5 is attached to the front end of the cutter shaft 9. The head cutter 5 has a large number of chips (blades) 11 at its front end. Reference numeral 12 is a buried pipe such as a vinyl chloride pipe, and reference numeral 13 is a casing of the head cutter 5. The head cutter 5 in such a conventional propulsion device excavates the earth and sand, and the earth and sand excavated by the head cutter 5 is carried out by the auger screw 1 to the starting shaft side. Therefore, there are various shapes of the head cutter 5, but each has a large opening 15 for guiding the earth and sand excavated by the head cutter 5 to the auger screw 1.

[0003]

However, since the conventional head cutter 5 has the large opening 15 for guiding the excavated earth and sand to the auger screw 1 as described above, a large stone in the earth is present. 17 is often passed through the opening 15 and caught in the auger screw 1. When large stones are taken in as described above, the auger screw 1 may be damaged, and the buried pipe 12 may be damaged. The present invention has been made in order to solve such a problem.

[0004]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a head cutter for propulsion, which limits the intake of large stones. That is,
The present invention provides a taper portion at the front end of a cutter shaft attached to the front end of the shaft of an auger screw (referred to as the left end in FIG. 1), and forming a spiral ridge on the surface of the taper portion. Has a pitch corresponding to the size of the largest stone that can be taken in, and the rear of the spiral ridge (Fig. 1
Refers to the right side. ) Is fixed to the cutter casing, the front edge of the cutter casing is parallel to the rear end of the spiral ridge, and the distance from the rear end is substantially equal to the pitch of the spiral ridge. A head cutter for propulsion is provided. (Claim 1)

The pitch of the spiral ridges is preferably 1/3 or less of the inner diameter of the cutter casing. (Claim 2)

[0006]

[Action]

[Propulsion head cutter according to claim 1] In the propulsion head cutter according to claim 1, the spiral protrusion provided on the cutter shaft and the cutter casing fixed to the cutter shaft rotate together with the auger screw. The spiral ridge of the cutter shaft is cut into the sand and excavated. At this time, stones smaller than the pitch of the spiral ridges are taken into the valley bottom between the spiral ridges along with the soil, sent to the auger screw, and carried out to the starting shaft side by the auger screw. On the other hand, stones larger than the pitch of the spiral ridges are excluded laterally without being trapped between the spiral ridges. Further, since the front edge of the cutter casing is parallel to the rearmost portion of the spiral ridge and the distance to the rearmost portion is substantially equal to the pitch of the spiral ridge, stones larger than the pitch of the spiral ridge are spiraled. It does not enter the cutter casing through the gap between the rearmost portion of the ridge and the front edge of the cutter casing. In this way, since stones larger than the pitch of the spiral protrusions are prevented from being taken in, the auger screw is not damaged or the buried pipe is not damaged.

[Propulsion head cutter according to claim 2] In the propulsion head cutter according to claim 2, the pitch of the spiral projections is 1/3 or less of the inner diameter of the cutter casing. Therefore, the size of the stone taken in by the head cutter is also 1/3 or less of the inner diameter of the cutter casing. When the size of the taken-in stone is 1/3 or less of the inner diameter of the cutter casing, damage to the auger screw or damage to the buried pipe due to the taken-in stone is more completely prevented.

[0008]

Embodiments of the present invention will now be described with reference to the accompanying drawings. Reference numeral 21 is an auger screw of the propulsion device in the present invention, and 23 is a shaft of the auger screw 21.
A connecting means 25 is provided at the front end of the shaft 23 of the auger screw 21.
The cutter shaft 27 is connected via. A tapered portion 29 is provided at the front end of the cutter shaft 27, and a spiral ridge 31 is formed on the surface of the tapered portion 29. The spiral ridge 31 has a pitch a corresponding to the size of the largest stone that can be taken in. Further, the support member 3 is provided on the cutter shaft 27 behind the spiral protrusion 31.
The cutter casing 35 is fixed via 3. The front edge 37 of the cutter casing 35 is the rearmost portion 3 of the spiral ridge 31.
1 ', and the distance a'from the rearmost portion 31' is made substantially equal to the pitch a of the spiral ridges 31. In addition, the spiral ridge 31 and the front edge 37 of the cutter casing 35.
A tip (blade) 39 is attached to each. Reference numeral 41
Is a buried pipe, and reference numeral 42 is a large stone that is removed laterally. In the present invention, the lead tube 43 may be previously propelled, the lead tube 43 may be connected to the tip of the cutter shaft 27, and the lead tube 43 may be propelled as a guide tube. Alternatively, a one-step method that does not use the lead tube 43 may be adopted. The propulsion head cutter according to the present invention is particularly effective for a gravel layer, a soft rock layer, a cobblestone layer, and the like.

The pitch a of the spiral ridges 31 is preferably 1/3 or less of the inner diameter b of the cutter casing 35. That is, a ≦ b / 3.

[0010]

As described above, the head cutter for propulsion according to the first aspect of the invention eliminates stones of a certain size or more laterally and prevents such stones from being caught in the auger screw. Damage the auger screw,
Or the buried pipe will not be damaged.

Particularly, in the propulsion head cutter of the second aspect, since the size of the stone taken in is 1/3 or less of the inner diameter of the cutter casing, the auger screw is damaged by the taken stone or the buried pipe is buried. Is more completely prevented from being damaged.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a propulsion head cutter according to the present invention.

FIG. 2 is a cross-sectional view showing an example of a conventional propulsion head cutter.

FIG. 3 is a front view of a conventional propulsion head cutter.

[Explanation of symbols]

 1 Auger Screw 3 Shaft 5 Head Cutter 7 Connecting Means 9 Cutter Shaft 11 Tip 12 Buried Pipe 13 Casing 15 Opening 17 Large Stone 21 Auger Screw 23 Shaft 25 Connecting Means 27 Cutter Shaft 29 Tapered Part 31 Spiral Ridge 31 'Last Part 33 Support member 35 Cutter casing 37 Front edge 39 Tip 41 Buried pipe 42 Large stone 43 Reed pipe

Claims (2)

[Claims] 1. A taper portion is provided at a front end of a cutter shaft attached to a front end of an auger screw shaft, and a spiral ridge is formed on a surface of the taper portion. It has a pitch corresponding to the dimensions, and the cutter casing is fixed to the rear of the spiral ridge on the cutter shaft,
A head cutter for propulsion, wherein a front edge of the cutter casing is parallel to the rearmost portion of the spiral ridge, and a distance from the rearmost portion is substantially equal to a pitch of the spiral ridge. 2. A cutter shaft attached to a front end of an auger screw shaft is provided with a taper portion at a front end thereof, and a spiral projection is formed on a surface of the taper portion, and the cutter shaft is provided with a cutter behind the spiral projection. The casing is fixed, the spiral ridge has a pitch of 1/3 or less of the inner diameter of the cutter casing, the front edge of the cutter casing is parallel to the rear end of the spiral ridge, and the interval between the rear end and the spiral protrusion is spiral. A head cutter for propulsion, which is characterized in that the pitch is substantially equal to the pitch.