JPH02265412A - lawn mower - Google Patents

Abstract

PURPOSE:To obtain a lawn mower capable of mowing lawn in raised state, having excellent lawn mowing properties by making rotation diameter of a discharge fan arranged above a cutter blade larger than that of the cutter blade. CONSTITUTION:During lawn mowing, lawn is mowed by rotation of a cutter blade by an engine 3. Then, the mowed lawn is transported from an outlet 19 of a cutter housing 2 to a grass bag 20 by a lower rpm discharge fan 7 of large volume. Then, during the lawn mowing, as shown in the figure, the lawn 34 is laid in the advance direction at the front part of advance of a peripheral wall 2b covering a cutter blade 6 of the housing 2. But the lawn 34 is raised by the upper fan 7 at a gap between the peripheral wall 2b and the tip of the blade 6 and mowed in a raised state by the blade 6. Therefore, the lawn 34 is excellently mowed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lawn mower equipped with a discharge fan that conveys grass cut by a cutter blade.

[Conventional technology]

A lawnmower cuts grass by rotating a cutter blade inside a cutter housing using, for example, an engine mounted on the cutter housing.

Then, the grass cut inside the cutter housing is discharged to the outside from the outlet of the cutter housing by the conveying wind generated by the twist provided in the cutter blade, or is transported and stored in the grass bag at the rear via the chute. Ru.

The cutter blade is usually a flat plate member that is rectangular in plan view.The output shaft of the engine is attached to the center of the cutter blade, and blade portions are formed on the front edges in the rotational direction at both longitudinal ends, and grass clippings are conveyed on the rear edges in the rotational direction. The structure is such that a wind generating twist is formed in an upright manner, the cutter blade is rotated to cut the grass with the cutting part, and the twist part generates conveying wind.

It is also known that a discharge fan is disposed above the cutter blade within the cutter housing. In this type, a discharge fan is fixed to the output shaft of the engine, its rotation diameter is smaller than that of the cutter blade, and it rotates at the same rotation speed as the cutter blade.

The grass cut by the cutter blade is transported to, for example, a rear grass bag by the transport wind generated by the cutter blade and the discharge fan.

[Problem to be solved by the invention]

However, in the lawn mower of this building, if the gap between both ends of the cutter blade and the peripheral wall of the cutter housing that covers it is too large, the grass clippings may blow out from the gap. Gaps are strictly regulated. Therefore, when mowing the grass, if the grass is pushed down in the traveling direction by the front part of the peripheral wall of the Kahuku housing, the grass will be cut in that state by the cutter blade. In this way, since the grass is mowed in a lying state, the grass may not be mowed well.

Further, in this type of lawn mower, wind noise is generated when the cutter blade rotates. This is thought to be due to the turbulence generated by the twisted portion of the cutter blade when the cutter blade rotates, and the collision of the cutter blade with the turbulence. In addition, those equipped with a discharge fan rotate at the same high rotational speed as the cutter blade, and thus generate wind noise like the cutter blade.

The present invention has been made in view of the above points, and an object of the present invention is to improve lawn mowing performance and reduce wind noise during lawn mowing.

(Means for Solving Ifl) The structure of the present invention provides a lawn mower including a discharge fan in the cutter housing that conveys the grass cut by the cutter blade in the cutter housing, in which the Kanthal blade has only a lawn mowing function. In addition, the discharge fan disposed above the cutter blade has a rotation diameter larger than the rotation diameter of the cutter blade.

Preferably, the rotational speed of the discharge fan is set to be faster than the rotational speed of the cutter blade.

C action] When mowing the lawn, as shown in Fig. 4, the front part of the peripheral wall of the cutter housing that covers the cutter blade pushes down the grass in the direction of travel, but the force 7 The grass is raised in the gap between the tip of the turbine blade and the tip of the blade by a discharge fan, and the grass is cut in an upright position by a cutter blade. Therefore, the mowing performance of the grass is improved.

In addition, the cutter blade does not have an upright twist to create wind to convey the cut grass, and has only the function of mowing the grass.
Wind noise can be kept low even when rotating at high speeds.
The grass clippings are transported by a discharge fan. By setting the rotation speed of the discharge fan lower than the rotation speed of the cutter blade, wind noise can be further reduced.

〔Example〕

FIG. 1 is a side view of the walk-behind lawn mower, FIG. 2 is a vertical sectional view of the main part thereof, and FIG. 3 is a plan view of the main part.

The lawn mower 1 is a walking type lawn mower, and the cutter housing 2
An engine 3 is mounted on top, and an output shaft 4 extends vertically downward through a central opening 5 in a clay wall 2a of the cutter housing 2, and a cutter blade 6 is fixed to the lower end of the output shaft 4.

The cutter blade 6 is a flat plate member with a rectangular shape in plan view.The output shaft 4 is fixed to the center, blades are formed on the side edges of both longitudinal ends, and the cross section in the width direction is a parallelogram (see Fig. 5). ), this cutter blade 6 has no upright twists formed on the side edges of both ends to generate a wind to convey the cut grass.

The rotation of the cutter blade 6 cuts the grass in the cutter housing 2, and the cut grass is conveyed by a large-capacity, low-rotation discharge fan 7 disposed above the cutter blade 6 in the cutter housing 2.

The discharge fan 7 is configured to be rotationally driven by the output shaft 4 via a speed reduction mechanism.

To explain this below, a fan holder 8 is rotatably inserted into the output shaft 4 above the cutter blade 6 via a bearing 9.

A discharge fan 7 is fixed to the fan holder 8 above the cutter blade 6 in the cutter housing 2, and the discharge fan 7 has a rotation diameter larger than that of the cutter blade 6.

The fan holder 8 passes through the center opening 5 of the cutter housing 2 and extends upward.
A pulley 10 is integrally formed in a portion above the upper surface of. One pulley 11 is fixed to the output shaft 4 above the fan holder 8, and two-stage pulleys 12 and 13 are provided above the cutter housing 2. A transmission belt 14. 15 is wound around the output shaft 4, and the power of the output shaft 4 is transmitted to the fan holder 8 through these two belts 14 and 15, and rotationally drives the discharge fan. In this case, the rotational speed of the discharge shifter 17 is transmitted to the pulley 10. at a speed lower than that of the output shaft 4.
11, 12, 13 diameters are set.

Therefore, the cutter blade 6 rotates at the same rotation speed as the output shaft 4, but the discharge fan 7 is decelerated and rotates at a lower speed than the cutter blade 6.

16 and 17 are wheels provided at the front and rear of the cutter housing 2, 18 is a handle extending rearward from the rear of the cutter housing 2, 19 is a discharge port provided at the rear of the cutter housing 2, and 20 is a cutter housing 2 It is a glass bag attached to the rear of the car.

Therefore, when mowing the lawn, the cutter blade 6 is rotated by the engine 3 to cut the lawn, and the cut grass is transported from the discharge port 19 of the cutter housing 2 into the grass bag 20 by the large-capacity, low-speed discharge fan 7. be done. When mowing the lawn, as shown in FIG. 4, the grass 34 is pushed down in the forward direction of the peripheral wall 2b covering the cutter blade 6 of the cutter housing 2, but the grass 34 is pushed down in the forward direction by the peripheral wall 2b of the cutter housing 2 and the cutter blade 6. The grass 34 is raised in the gap between the tip of the blade 6 by the discharge fan 7 above, and the grass 34 is cut by the cutter blade 6 in an upright state. Therefore, the grass 34 can be mowed well.

Note that the cutter blade 6 is not limited to the rectangular plate member shown above (see FIG. 3); for example, a parallelogram-shaped plate member (see FIGS. 6(A) and (B)), It may be a slender rod-shaped plate member (see Fig. 6 (C)), a disc with a pair of opposing round bars protruding from it (see Fig. 6 (D)), etc., and the cross-sectional shape in the width direction may be Although the parallelogram shape shown above (see FIG. 5) is preferable in terms of keeping wind noise low, it is not limited to this.

Rotation diameter, rotation speed, and blades 7a of the discharge fan 7
The number of blades 7a, twist height, etc. may be selected as appropriate, but as the rotation speed is reduced, the number of blades 7a may be increased and the twist height may be increased.
rpm, the number of blades 7a is 6, and the twist height of blade 7a is 5.
0 mm, and the twisted shape of the blade 7a is configured to form a curved surface shape with an entrance angle α of 30' and a discharge angle β of 45°, as shown in FIG.

Furthermore, the speed reduction mechanism for the discharge fan 7 is not limited to the one shown above, and the ones shown in FIGS. 8 to 10, for example, may be used as appropriate.

8 shows a case where the rotation axis 2l of the cutter blade 6 is not on the same straight line as the output shaft 4 of the engine 3, and the upper pulley 22 of the output shaft 4 and the pulley 23 of the rotation shaft 21
The cutter blade 6 is rotationally driven by a belt 24 wound between the lower pulley 25 of the output shaft 4 and the rotating shaft 21.
The belt 27 is wound between the pulleys 26 of the fan holder 8, which is rotatably attached to the fan holder 8.
The discharge fan 7 fixedly rotates at a reduced speed.

In the one shown in FIG. 9, a cutter blade 6 is fixed to the output shaft 4 of the engine 3 and driven to rotate, and a gear 29 is provided on the top of a fan holder 8 rotatably attached to the output shaft 4. The discharge fan 7 fixed to the fan holder 8 rotates at a reduced speed by being driven at a reduced speed by a gear 30 of the camshaft 28. In the one shown in FIG. 10, a cutter blade 6 is fixed to the output shaft 4 of an engine 3 and driven to rotate, and a fan holder 8 rotatably attached to the output shaft 4 is connected to a sun gear 31 fixed to the output shaft 4. A discharge fan fixed to the fan holder 8 rotates at a reduced speed by being disposed between the ring gear 32 and the surrounding ring gear 32 or connected to a reduction gear 33 to be driven at a reduced speed.

〔Effect of the invention〕

As explained above, in the present invention, the rotation diameter of the discharge fan disposed above the cutter blade is made larger than the rotation diameter of the cutter blade. Therefore, when mowing the lawn, the lawn can be cut in an upright state, and the mowing performance of the lawn is improved. In addition, the cutter blade does not have a twist to create a wind to convey the cut grass, and has only the function of cutting the grass. Therefore, even if the cutter blade rotates at high speed, wind noise can be suppressed to a low level. The function of transporting the cut grass is replaced by a discharge fan, and by lowering the rotation speed of this fan, wind noise can be further reduced.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a side view of a walk-behind lawn mower showing an example of the present invention, FIG. 2 is a vertical sectional view of the main part thereof, and FIG. Fig. 4 is a partially enlarged view of Fig. 2, Fig. 5 is a cross-sectional view in the width direction of the cutter blade, Fig. 6 is a plan view of the cutter blade, Fig. 7 is a diagram showing a part of the discharge fan, Fig. 8- FIG. 10 is a diagram showing the speed reduction mechanism. 1 is a lawn mower, 2 is a cutter housing, 2a is an upper wall, 2
b is a peripheral wall, 3 is an engine, 4 is an output shaft, 5 is an opening, 6 is a cutter blade, 7 is a discharge fan, 7a is a blade, 8 is a fan holder 9 is a bearing, 10, 11
, 12.13 is a pulley, 14.15 is a belt, 16.
17 is a wheel, 18 is a handle, 19 is an outlet, 20 is a grass bag, and 34 is a lawn.

Claims (2)

[Claims] (1) In a lawn mower that includes a discharge fan in the cutter housing that transports grass cut by a cutter blade in the cutter housing, the cutter blade has only a lawn mowing function and is arranged above the cutter blade. A lawn mower characterized in that a rotation diameter of the discharge fan is larger than a rotation diameter of the cutter blade. (2) In a lawn mower that includes a discharge fan in the cutter housing that transports grass cut by a cutter blade in the cutter housing, the cutter blade has only a lawn mowing function and is arranged above the cutter blade. A lawnmower characterized in that the rotational diameter of the discharge fan is larger than the rotational diameter of the cutter blade, and the rotational speed of the discharge fan is lower than the rotational speed of the cutter blade.