JP2527984Y2 - Lawn mower cutting blade device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mowing blade device for a lawn mower, and more particularly to a structure of a mowing blade portion of an upper and lower cutter blade that rotates substantially horizontally.

[0002]

2. Description of the Related Art In a lawn mower in which a cutter blade that rotates substantially horizontally is housed in a cutter housing having an open lower surface, two upper and lower cutter blades are stacked, and the cutting blade of an upper cutter blade is used as a lower blade. A technique for cutting lawn grass twice by being positioned in the rotation direction forward with respect to the cutting blade is disclosed in U.S. Pat. No. 2,760,32.
No. 7 discloses it.

[0003]

Conventionally, in order to position the upper cutting blade in front of the lower cutting blade in the rotational direction as described above, the upper and lower cutter blades are previously overlapped by changing the angle in plan view in advance. Since it is troublesome to assemble and superimpose at different angles, the upper and lower cutter blades may be overlapped in the longitudinal direction. However, if the upper and lower cutter blades having the same longitudinal direction and the upper and lower cutter blades have the same width in the rotational direction and the upper and lower front end surfaces and the rear end surfaces thereof are aligned with respect to the rotational direction, the upper and lower cutter blades are aligned in the rotational state, and Wind noise is generated by the front end face that is thicker in the direction,
There is also a problem that a vortex of air is generated behind the rear end face which is similarly aligned and becomes thicker in the vertical direction, so that noise is easily generated.

Accordingly, an object of the present invention is to provide a lawn mower in which two upper and lower cutter blades whose upper cutting blades are located forward in the rotation direction are stacked in the longitudinal direction for simplicity of assembly. An object of the present invention is to provide a cutting blade device that makes it difficult to generate wind noise at the front end face and air vortices at the rear, thereby suppressing generation of noise.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a cutter blade which rotates substantially horizontally, provided at a lower end portion of a substantially vertical rotating shaft which is vertically overlapped , and a cutting blade of an upper cutter blade. In the lawn mower in which the upper and lower cutter blades are positioned in front of the lower cutter blade in the rotation direction, the upper and lower cutter blades are aligned in the longitudinal direction, and the relationship between the upper and lower cutter blades is determined.
Near the center of rotation of the blade, the width of the upper cutter blade
Is larger than the width of the lower cutter blade, and
At the cutting blade part of the cutter blade,
The width of the blade is smaller than the width of the lower cutter blade .

[0006]

[Function] By assembling the upper and lower cutter blades in the longitudinal direction, assembling can be performed more easily as compared with the case where the upper and lower cutter blades are overlapped at different angles, and the width of the upper cutter blade is smaller than that of the upper cutter blade. Since the lower cutter blade is superimposed, the front end face and rear end face become uneven, making it difficult for wind noise to occur at the front end in a rotating state and for air vortices at the rear to be less likely to occur. It is difficult to get out.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cutaway view of a cutter housing 1 together with a cutting blade device to which the present invention is applied, 2 is a wheel, 3 is an engine case, 4 is a rotating shaft, 5 is a blade holder,
6 and 7 are cutter blades. As shown also in FIG. 2, an upper cutter blade 6 and a lower cutter are provided at the lower end of a substantially vertical rotating shaft 4 driven by an engine through the center of the upper wall of the cutter housing 1 via a blade holder 5. The blades 7 are aligned in the longitudinal direction, overlapped at the center, and fixed by bolts and nuts. Thereby, both cutter blades 6 and 7 are driven to rotate substantially horizontally.

The upper cutter blade 6 is shown in FIGS.
As shown in FIG. 5, the cutting blades 61 are formed at both ends of the cutting blades, and the rear portions in the rotation direction of the cutting blades 61 are formed as oblique cut portions 62. It is a pressed plate-like member that is lowered one step through step portions 63, 63 bent downward from the center. Here, the cutting blade 61 is formed over the step portion 63, and the oblique cut portion 62 is formed as large as the step portion 63 and the center. The step 63 is for reducing impact on both ends, and the step 63 is formed with a concave groove 64 for securing rigidity bulging downward toward the center.

The lower cutter blade 7 is shown in FIGS.
As shown in FIG. 5, the cutting blades 71, 71 are formed at both ends of the cutting blades 71, and the rear portions in the rotation direction of the cutting blades 71, 71 are raised upward along diagonal lines to form a substantially triangular shape. It is a press plate formed in the blast portions 72, 72 and lowered by one step through step portions 73, 73 whose both ends are bent downward from the center. Here, both the cutting blade 71 and the draft part 72 are formed over the step part 73. Similarly to the above, the step portion 73 is for reducing impact on both ends, and the step portion 73 is formed with a concave groove 74 for securing rigidity which swells downward toward the center.

As shown in FIGS. 3, 4 and 6, the upper and lower cutter blades 7 have a width W1 lower than the width W1. The width W2 is smaller, and the cutting blade 61 of the upper cutter blade 6 is positioned ahead of the cutting blade 71 of the lower cutter blade 7 by a predetermined dimension a in the rotation direction R. As shown in FIG. 1, a predetermined clearance b is secured between the upper and lower cutting blades 61 and 71, and the blast portion 72 of the lower cutter blade 7.
Is formed sufficiently higher than the cutting blade 61 portion of the upper cutter blade 6 by a predetermined dimension c, and as shown in FIG.
Oblique cutting part 6 on the rear side in the rotation direction of upper cutting blade 61
2 is almost in a state of approach.

According to the cutting blade device having the above configuration, in the rotating state of the blade, first, the upper cutting blade 61 cuts the upper part of the turf grass, and after a short time delay, the lower cutting blade 71 cuts the turf grass further. . This lower cutting blade 7
1 and the second cutting is performed, the upper cutting blade 6
The turfgrass is pulled up by the negative pressure suction effect of the increased wind flowing upward along the wind generating portion 72 formed sufficiently higher than 1, and the lower cutting blade 71 reliably cuts the grass in a short time.
Moreover, the cut turf is blown upward, falls on the rotating cutter blades 6, 7, and is finely cut again by the upper and lower cutting blades 61, 71, and is finally dispersed on the turf ground.

The upper and lower cutter blades 6, 7 are
Because of the structure in which the longitudinal directions are aligned, the assembly can be performed more easily than in the conventional case where the angles are different from each other. Further, as shown in FIG. 8, the front end face and the rear end face have a width W1 of the upper cutter blade 6 and a lower cutter blade 7 having a width W2 smaller than the width W1. Compared with the case where the air flow is aligned, the change of the air flow is small, and it is difficult to generate the wind noise at the front end, and it is also hard to generate the vortex of the air at the rear, thereby suppressing the generation of noise.

Further, as shown in FIG. 9, the blast portion 72 of the lower cutter blade 7 which is sufficiently higher than the cutting blade 61 of the upper cutter blade 6 by the dimension c so as to increase the air volume is moved upward. Diagonal cut part 6 of cutter blade 6
2, because of the structure that is substantially in the proximity state along the
And the gap between the front and the oblique cut portion 62 is minimized, and it becomes difficult for air vortex to be generated at that portion, so that noise can be suppressed.

The cutting blade device according to the present invention is not limited to the walking lawn mower and the closed type cutter housing as in the embodiment, but can be applied to a riding lawn mower, a discharge type cutter housing, a storage in a glass bag, and the like. is there.

As described above, according to the present invention, in a lawn mower including two upper and lower cutter blades in which the upper cutting blade is positioned forward in the rotation direction, the upper and lower cutter blades are overlapped in the longitudinal direction. The assembly can be simplified as compared with the conventional case in which the angles are different from each other, and the relationship between the upper and lower cutter blades can be reduced.
Near the center of rotation of the cutter blade.
The width of the blade is larger than the width of the lower cutter blade,
At the cutting blades of the upper and lower cutter blades,
The width of the blade is smaller than the width of the lower cutter blade.
Therefore, the front end face and the rear end face are made irregular, so that wind noise at the front end in a rotating state can be made less likely to occur, and at the same time, air vortices at the rear can be made less likely to occur. Occurrence can be suppressed.

[Brief description of the drawings]

FIG. 1 is a cutaway side view of a cutter housing together with a cutting blade device to which the present invention is applied.

FIG. 2 is an exploded perspective view of the cutting blade device according to the present invention.

FIG. 3 is a plan view of the same assembled state.

FIG. 4 is a plan view of a single item of the upper cutter blade.

FIG. 5 is a side view of the same.

FIG. 6 is a plan view of a single piece of the lower cutter blade.

FIG. 7 is a side view of the same.

FIG. 8 is an essential part cross-sectional view for explaining the operation of the present invention along the line AA of FIG. 3;

9 is a sectional view taken along the line BB of FIG. 3;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cutter housing, 4 ... Rotating shaft, 5 ... Blade holder, 6 ... Upper cutter blade, 7 ... Lower cutter blade.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Minami Hanafusa 1-4-1 Chuo, Wako-shi, Saitama Pref. Honda Technology Research Institute Co., Ltd. (56) References Japanese Utility Model No. 4-55226 (JP, U) 1931-12436 (JP, Y1)

Claims (1)

(57) [Scope of request for utility model registration] 1. A cutter blade rotating substantially horizontally ,
A lawn mower that is provided at the lower end of a substantially vertical rotation shaft overlapped vertically and the cutting blade of the upper cutter blade is positioned forward in the rotation direction with respect to the cutting blade of the lower cutter blade. , together with the superimposed aligned longitudinally, the relationship of the upper and lower cutter blades, the cutter blade
Near the center of rotation of the blade, the width of the upper cutter blade is
Make it larger than the width of the lower cutter blade.
Cutter blade, the upper cutter blade
A cutting blade device for a lawn mower , wherein the width is smaller than the width of the lower cutter blade .