The shredding device comprises a rectangular housing a rotating shaft which penetrates the lateral the walls of the rectangular housing, a driving unit which rotates said rotating shaft, a plurality of disk-shaped cutters which are detachably mounted on the rotating shaft, each of the disk-shaped cutter has a plurality of cutter U-shaped concaves and which have predetermined-depth at every predetermined interval, a plurality of disk-shaped spacers which are detachably mounted on said rotating shaft, mounted between neighboring two of said disk-shaped cutters and which have a diameter smaller than a diameter of said disk-shaped cutter, and scrapers each of which is mounted on each of longitudinal side walls of said rectangular housing, and is arranged with predetermined gap against circumferences of the disc cutters and circumference of said disk-shaped spacers; wherein each of the disk-shaped cutters has a cutter groove running along its circumference.

TECHNICAL FIELD

This invention relates to a single-shaft shredding device, and especially relates to the single-shaft shredding device particularly suitable for crushing soft garbage such as used paper diaper.

BACKGROUND OF THE INVENTION

To recycle soft garbage such as used paper diaper, it is essential to crush it as small as possible and below a predetermined size.

A dual-shaft shredding device shown in Patent Literature 1 has been used previously to crush soft garbage.

The dual-shaft shredding device has two rotating shafts on which cutters and spacers are mounted alternately, and crushes soft garbage by trapping it in the gap between the cutter mounted on one rotating shaft and the spacer mounted on the other.

However, the dual-shaft shredding device shown in Patent Literature 1 has the unavoidable problem that the size of the shredding device will become large because the shredding device requires two rotating shafts.

Furthermore, the gap becomes easily clogged with soft garbage, when the gap between the cutter and the spacer is narrowed for crushing the soft garbage into thinner pieces.

When clogging occurs, not only the shredding device cannot continue operating, because pressing pressure which works against the cutter and the spacer becomes excessively, but also it becomes difficult to uniformly crush garbage into smaller size.

Even though Patent Literature 2 shows a shredding device having a screen at the discharge port to prevent the discharge of soft garbage that has not been crushed enough, this type shredding device becomes difficult to continuously operate due to screen clogging when the shredding device is applied for crushing soft garbage such as paper diaper.

PRIOR ART LITERATURE

Patent Literature

Patent literature 1: Japanese unexamined patent application No.2007-209932

Patent literature 2: Japanese patent publication No. 6476532

SUMMARY OF THE INVENTION

Problem to be solved by the invention

The purpose of this invention is to solve the above problem, and to provide a single-shaft shredding device that can continuously crush soft garbage equal to or less a predetermined size.

Means for solving the above problems

A single-shaft shredding device according to the first invention comprises,a rectangular housing,a rotating shaft which penetrates the rectangular housing,a driving unit which rotates the rotating shaft,a plurality of disk-shaped cutters which are detachably mounted on the rotating shaft, and each of them has a plurality of U-shaped cutter concaves having predetermined depth at every predetermined interval, a plurality of disk-shaped spacers which are detachably mounted on the rotating shaft, and mounted between adjacent two of the disk-shaped cutters, and each of them has a diameter smaller than a diameter of the disk-shaped cutter, anda plurality of scrapers each of which is mounted on each of side walls of the rectangular housing having predetermined gaps between circumferences of the disc cutters and between circumference of the disk-shaped spacers,wherein each of the disk-shaped cutters has a cutter groove running along its circumference.

The single-shaft shredding device according to the second invention, wherein each of the spacers has at least one spacer concave on its circumference.

The single-shaft shredding device according to the third invention, wherein the circumferences of the spacers exist outside the bottoms of the U-shaped cutter concave.

The single-shaft shredding device according to the fourth invention, wherein the driving unit rotates the rotating shaft to positive direction and negative direction.

Effect of the invention

According to the single-shaft shredding device of the first invention, it is possible to miniaturize the size of the shredding device.

Furthermore, even when soft garbage is caught in the gap between the cutter and the scraper, it is possible to suppress the pressing pressure against the housing, and overload of the driving unit. Therefore, the shredding device can continue its stable operation.

According to the single-shaft shredding device of the second invention, it becomes possible to prevent soft garbage from winding to the spacer and piling up on the spacer and the scraper.

According to the single-shaft shredding device of the third invention, it becomes possible to discharge soft garbage which wound to the spacer and piled up on the spacer and the scraper to the cutter concave.

According to the single-shaft shredding device of the fourth invention, it becomes possible to easily continue its operation by switching the rotating direction even when garbage is caught in the gap between the cutter and the scraper and the pressing pressure against the housing increases.

EMBODIMENT FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the single-shaft shredding device according to this invention will be described with reference to the drawings.

At first, the configuration of the single-shaft shredding device according to this invention will be described.

FIG.1is a block diagram of the single-shaft type shredding device according to said invention.

FIG.2is a top view of the inside of the housing andFIG.3is a vertical sectional view of the inside of the housing.

A single-shaft shredding device according to this invention comprises, a rectangular housing1, a rotating shaft2which penetrate the rectangular housing1, a driving unit3which rotates the rotating shaft2, disk-shaped cutters4which are detachably mounted on the rotating shaft2in the housing1, disk-shaped spacers5which are detachably mounted on the rotating shaft2in the housing1, scrapers6which are mounted on side walls of the housing1, and provide predetermined gaps between the circumference of the cutters4and between the circumference of the spacers5at the level of the center of the rotating shaft2.

FIG.3(a)is cross section of the cutter4and the scraper6.FIG.3(b)is a cross section of the spacer5and the scraper6.

The scraper6has a triangular protrusion facing the cutter4and a flat base facing the spacer5.

As shown inFIG.3(a), a predetermined gap is provided between the base portion of the scraper6and the outer circumference of the cutter4.

Further, as shown inFIG.3(b), a predetermined gap is provided between the top of the projection portion of the scraper6and the outer circumference of the cutter4.

The cutter4has U-shaped cutter concaves having predetermined depth at every predetermined interval on the circumference.

The spacer5is mounted between two adjacent cutters4.

That is, the cutters4and the spacers5are alternately mounted on the rotating shaft2.

In the embodiment shown inFIG.1, an electric motor is used as the driving unit3, but another driving unit such as a hydraulic motor may be applied.

It is desirable that the driving unit can switch between forward rotation and reverse rotation.

FIG.4is an oblique figure of the cutter used in the single-shaft shredding device according to the invention.

That is, as shown inFIG.4(a), the cutter4has a disk-shaped, a fitting hole in the center thereof that is aligned with the rotating shaft2at the center, and a plurality of U-shaped cutter concaves at every predetermined interval.

Convex part between two adjacent cutter concaves41works as cutter hooks42.

As shown inFIG.4(b), a cutter groove43running along the circumference is formed on the upper surface of the cutter hook42, that is, the circumference of the cutter4.

The outside edges of the cutter groove43may have a sharp shape as shown inFIG.4(c)or a shape that leaves the circumference surface of the cutter as shown inFIG.4(d).

The cutter groove43may be V-shaped in which both walls form an acute angle at the bottom, or may be U-shaped in which the bottom forms a gentle surface.

FIG.5is a front view and a side view of the spacer used in the single-shaft shredding device according to the invention.

Namely, as shown inFIG.5(a), the spacer5is of the disc-shaped having an outer diameter smaller than that of the cutter4and has a fitting hole in the center thereof that is aligned with the rotating shaft2.

Further, at least one spacer concave51, which is a groove having a rectangular cross section, is formed on the outer circumference of the spacer5.

The shape of the spacer concave51may be a trapezoidal shape having a short side at the bottom and a long side at the circumference as shown inFIG.5(b), or a groove shape as shown inFIG.5(c).

Further, the spacer concave51may be formed parallel to the rotation axis direction as shown inFIG.5(d) or diagonally to the rotation axis direction as shown inFIG.5(e).

FIG.6is an oblique figure in which the cutter and the spacer are stacked.

Namely, the fitting hole of the cutter4and the hole of the spacer5have the same shape, and the cutters4and the spacers5are alternately mounted on the rotating shaft2.

The outer diameter of the spacer5is smaller than the outer diameter of the cutter4, but the circumference of the spacer5is set to be outside the bottom of the cutter groove43formed in the cutter4.

FIG.7is an oblique figure of a rotating body in which cutters4and spacers5are alternately arranged, and it is desirable that the cutter hook42are arranged in a spiral shape in direction of the rotating shaft2. Next, the operation of the single-shaft shredding device according to the invention will be described.

FIG.8is an explanatory figure of an operating method of the single-shaft shredding device according to the invention.

First, a case where the rotating shaft2of the single-shaft shredding device is rotated clockwise (positive direction) by the driving unit3will be described.

Soft garbage8such as a paper diaper is charged from the charging port provided in the upper part of the housing1(FIG.8(a)).

The soft garbage8is carried to the right side of the housing1by the cutter hook42(FIG.8(b)).

The soft garbage8is caught in a gap between the base part of the scraper6mounted on the right wall of the housing1and the cutter4, and a shearing of the soft garbage is started (FIG.8(c)).

Since a V-shaped cutter groove43is provided on the outer circumferential surface of the cutter hook42, the shredding device can finely crush the soft garbage while suppressing the pressing pressure against the housing1even when soft garbage is caught in the gap between the base part of the scraper6and the cutter4(FIG.8(d)).

When the cutter4is continuously rotated clockwise to continue crushing of the soft garbage8, it may become difficult for the driving unit3to rotate the rotating shaft2, because the soft garbage8clogs the gap between the cutter4and the base part of the scraper6and the pressing pressure increases.

In order to prevent the rotating shaft2from stopping, the rotating shaft2is rotated counterclockwise (negative direction) after rotated clockwise for a time (FIG.8(e)).

Then, the soft garbage8is carried to the left side of the housing1by the cutter hook42(FIG.8(f)).

The soft garbage8is pressed against the base part of the scraper6mounted on the left wall of the housing1(FIG.8(g)), and shearing is started (FIG.8(h)).

The rotation direction of the rotating shaft2is generally switched at predetermined time intervals.

When the driving unit2is an electric motor, the rotation direction may be switched when the current flowing through the electric motor exceeds a predetermined threshold current.

Further, when the driving unit2is a hydraulic motor, the rotation direction may be switched when the hydraulic pressure supplied to the hydraulic motor exceeds a predetermined threshold hydraulic pressure.

Namely, by operating the single-shaft shredding device according to the invention as described above, it is possible to continue the operation even when the amount of the soft garbage8increases, while suppressing the pressing pressure on the housing1from becoming excessive.

Further, by the single-shaft shredding device according to the invention, it is possible to prevent the soft garbage from winding around the spacer5and from accumulating on the spacer5and the scraper6, by providing the spacer5with at least one spacer concave51.

As the outer diameter of the spacer5is decided so that the outer circumferential edge of the spacer5is outside the bottom of the cutter concave41provided in the cutter4, the soft garbage wrapped around the spacer5and accumulated on the spacer5and the scraper6can easily move to the cutter concave41, and accumulating and winding of the soft garbage8can be suppressed.

INDUSTRIAL APPLICABILITY

The single-shaft shredding device according to the invention can continuously crush soft garbage such as paper diapers to a uniform size, and accordingly has industrial applicability.

DESCRIPTION OF FIGURES