JPH10229722A - Cutter for mower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a vibration or a wavy phenomenon accompanying with the rotation of rotary cutter for mower. SOLUTION: The disk-shaped cutter is rotated by motive force, and grass is mown by rotating this cutter. Concerning such a mower, the cutter 20 is formed into round saw equipped with a mowing blade around its outer peripheral part, and a loop-shaped projecting part 23 is integrally provided on the lower surface of cutter 20 so as to be protruded downward.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutter for a brush cutter, which is provided with a cutter which is rotated by power, which is gripped by an operator by hand, and a rotating cutter at the tip of the cutter faces the grass to cut the grass. It is about.

[0002]

2. Description of the Related Art A rotary cutter driven by an engine is provided, an engine portion is carried by a shoulder, a shaft member is provided with a handle portion, and a rotary cutter at a tip end portion of the shaft member faces a weed or the like. The power-type mower that reaps is actually open flat 5-7.
No. 4224 and others.

The cutting cutter of this type of brush cutter is generally of a disk shape and has a plurality of cutting blades on the outer periphery in many cases. There is also a type in which two brush cutters project symmetrically outward in the radial direction.

[0004]

In the above-mentioned rotary cutter of the bush cutter, the disk-shaped rotary cutter has a circular saw shape having a plurality of cutting blades circumferentially separated from each other on an outer peripheral portion thereof. Weeds are cut by a cutting blade and cut off. In conventional cutters, only a plurality of cutting blades are provided on the outer periphery of a disk-shaped cutter body, so that when the cutting blade rotates, the cutting blade comes into direct contact with the weeds and the like. Cutting and mowing work.

[0005] Incidentally, the cutter is formed in a disk shape and made of a steel plate material, and its outer diameter needs to be large to some extent, and the cutter at the tip of the brush cutter tends to be heavy. As the weight of the cutter increases, the weight of the tip of the brush cutter also increases, and since the cutter rotates at a high speed, the rotational inertia of the cutter increases, and it is desirable that the cutter be light in operation. It is desired that

When the cutter is made of a thin steel plate material in order to reduce the weight, the rigidity is low, and the high speed rotation at the time of the cutting operation may cause the entire cutter to swing and generate a waving phenomenon. Performance decreases.

On the other hand, the bush cutter carries a heavy engine by a shoulder, grips a handle provided on a long shaft-like member, and performs a cutting operation with a rotary cutter facing the tip of the shaft-like member facing a weed or the like. . For this reason, there is a distance between the cutter and the operator, the tip of the bush cutter including the cutter swings because the cutter is rotating, and it is necessary to operate the engine part while carrying it. Therefore, it is difficult to accurately follow the weeds of the cutter part.

[0008] Therefore, when obstacles such as pebbles and garden stones are mixed in weeds and the like, the cutting blade may come into contact with these obstacles and damage the cutting blade.

The present invention has been made to solve the above problems. It is an object of the present invention to provide a rotary cutter for a brush cutter, wherein the rotary cutter has a preferable diameter for the cutting function of weeds, the thickness of the cutter is reduced, the weight of the cutter is reduced, and the operability of the cutter is improved. To improve the rigidity of the cutter while satisfying these requirements, to prevent runout and waving of the cutter due to the thinning of the cutter, to provide a thin and lightweight cutter with excellent cutting performance, and to provide a cutting blade for the cutter. An object of the present invention is to provide a cutter for a brush cutter that can prevent the contact of a part with an obstacle and improve the durability and life of the cutter.

[0010]

According to a first aspect of the present invention, there is provided a brush cutter in which a disk-shaped cutter is rotated by power and grass is cut by the rotation of the cutter. The cutter has a circular saw shape with a cutting blade, and the cutter has an annular convex portion integrally provided on the lower surface thereof so as to protrude downward.

In the first aspect, the annular convex portion is integrally provided so as to protrude from the lower surface of the disk-shaped cutter, so that the annular convex portion functions as a reinforcing rib, and the vertical deflection of the disk-shaped cutter. And waving phenomena. In addition, when there is an obstacle below the cutter when weeding, it is possible to detect and sense that the annular convex portion first contacts the obstacle and interferes with the obstacle.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings should be viewed in the direction of reference numerals. 1 is a perspective view showing an example of a brush cutter, FIG. 2 is an enlarged vertical sectional side view of a cutter portion of the brush cutter, FIG. 3 is a plan view of the cutter, and FIG. 4 is a longitudinal sectional view of the cutter.

FIG. 1 shows an example of a brush cutter 1, in which an engine 3 is provided at an upper end of a straight pipe 2, the engine 3 is provided with a crankcase 4, a cylinder head 5, and a cylinder head 5 is provided. The outside is covered by a cylinder head cover 5a, and a recoil starter 6 is provided at the rear of the crankcase 4 in the embodiment.

A cylindrical extension 7 is provided on the front of the crankcase 4 to hold and cover the outer periphery of the output shaft, and the upper end of the tube 2 is joined to the cylindrical extension 7 by fitting or the like. A drive shaft 8 having an upper end connected to an output shaft in the tube 2 is fitted and held. The output end of the drive shaft 8, that is, the lower end 8a is shown in FIG.

A bar-type handle 9 is provided at an upper intermediate portion of the tube 2.
The handle 9 is substantially U-shaped, has grip portions 9a at both ends, and is fixed to the tube 2 by a handle bracket 9b at the center. A throttle lever 10 for controlling the number of revolutions of the engine is provided near one grip portion of the handle 9.

As shown in FIG. 2, the lower end 2a of the tubular body 2 is fitted and fixed to a cylindrical one end 10a which is inclined upward and rearward of a substantially L-shaped gear case 10 as viewed from the side. A spline engaging portion 8b extends from a lower end portion 8a of the drive shaft 8 facing the shaft, and engages a base 11a of a drive bevel gear 11 disposed in the gear case 10 via the engaging portion 8b. The outer periphery of the shaft 11 a of the bevel gear 11 is rotatably held by a bearing 12 provided in the base of one end 10 a of the gear case 10.

The other vertical cylindrical end portion 10 of the gear case 10
A rotating shaft 13, which is a driven shaft, is accommodated and disposed in a vertical direction in b, and the upper and lower portions of the rotating shaft 13 are rotatably supported by bearings 14 and 15. A driven bevel gear 16 is provided. The bevel gear 16 of the rotating shaft 13 and the bevel gear 11 at the lower end of the driving shaft 8 are meshed with each other, and the power of the driving shaft 8 is transmitted to the rotating shaft 13.

The lower end of the rotating shaft 13 projects below the cylindrical other end 10a to form a mounting boss 13a. The mounting boss 13a has a step 13b having a small diameter. 13c, a mounting hole 21 provided in the center of the cutter 20
Is fitted from below, and a bolt 18 is screwed from below into a screw hole 13 d provided in the axial direction of the rotating shaft 13 via a washer 17, and the cutter 20 is detachably fixed to the rotating shaft 13.

A guard plate 19 is provided in front of the case 10 at the end of the tubular body 2 provided with the cutter 20 described above. The guard plate 19 has a width in the left-right direction slightly larger than the diameter of the cutter 20. The dimension in the direction is small, and the cutter 20 is configured so that the cutter 20 can be easily checked from above.
Is a boss portion 19a provided at the upper part of the center and divided into two pipes.
Can be moved in the axial direction of the tube body 2 by loosening the tightening, and the position of the guard plate 19 can be adjusted.

FIGS. 3 and 4 show the cutter 20, and FIGS. 2 and 3 each show a longitudinal sectional view of the cutter. In order to facilitate understanding, the thickness of the cutter 20 is shown larger than the actual thickness. I have. The cutter 20 is formed in a disc shape from a steel plate material, and has a mounting hole 21 at the center.

The outer peripheral portion is provided with a large number of cutting blades 22. In the embodiment, the cutting blade has a circular saw shape having a large number of blades. The above-mentioned cutter 20 is provided with an annular projection 23 integrally.

The annular projection 23 has an annular shape centered on the center of the cutter, has a predetermined width in the radial direction, and is provided so as to project downward. As shown in FIGS. 4 and 2, the cutter 20 is formed as an annular concave groove 23a on the upper surface 20a and protrudes as an annular convex portion 23b on the lower surface 20b.

The annular convex portion 23 is provided on the circumference of about 2/3 from the center of the cutter 20. The reason why the annular convex portion 23 is provided on the circumference of approximately 2/3 from the center of the cutter 20 is that the annular convex portion 23 contributes to increase the rigidity of the disk-shaped cutter made of a steel plate, and If the position is close to the cutting blades 22, the annular convex portion 23 on the lower surface of the cutter may lay down the weeds and the like to be cut down, and may reduce the function of cutting the weeds and the like by the cutting blades 22. Therefore, the annular convex portion 23 is approximately 2/3 from the center of the cutter 20.
It is preferable to provide it on the circumference of the order.

As described above, the annular convex portion 23 is
The rigidity of the cutter 20 is remarkably improved by providing it at the zero disk portion. In practice, as shown in FIG. 2, the cutter 20 is attached to the rotating shaft 18 at the center at the mounting hole 21, thereby increasing the rigidity. Even if it is provided in the deviated portion, the overall rigidity can be increased.

Since the annular convex portion 23 projects below the disk-shaped cutter 20, if there is an obstacle such as a stone below the cutter 20 when weeds or the like are cut by the cutter, the cutting blades 22. Before that, the lower protruding portion 23b of the annular convex portion 23 comes into contact with the obstacle. As a result,
The contact of the annular projection 23 with the obstacle is transmitted to the handle 9 via the gear case 10 and the tube 2, and it is found that the cutter 20 interferes with the obstacle. That is, the obstacle is detected and sensed. Can be. Further, when the annular projection 23 comes into contact with the obstacle, abnormal noise is generated, and it can be detected and sensed that the cutter 20 interferes with the obstacle.

[0026]

According to the present invention, the following effects are exhibited by the above configuration. According to claim 1, in a brush cutter in which a disk-shaped cutter is rotated by power and grass is cut by the rotation of the cutter, the cutter has a circular saw shape having a cutting blade on an outer peripheral portion. Since the annular convex portion is integrally provided on the lower surface so as to protrude downward, the rigidity of the disc-shaped cutter can be increased by the annular convex portion.

[0027] Accordingly, sufficient rigidity can be secured even if the thickness of the cutter is reduced in order to facilitate the operation of the tip of the brush cutter. It is possible to prevent run-out and waving of the rotating cutter, improve the cutting performance of the cutter, and efficiently cut weeds and the like.

Further, the present invention can reduce the thickness and weight of the cutter, so that the tip of the brush cutter can be reduced in weight, which contributes to obtaining a brush cutter which is easy to operate and controls the tip. And also contributes to obtaining a brush cutter excellent in handling and usability.

Further, according to the present invention, the annular convex portion is provided so as to protrude from the lower surface of the cutter. Therefore, when there is an obstacle such as a stone below the cutter when cutting weeds or the like, first, the annular convex portion is moved to the obstacle. This makes it possible to detect and sense that the cutter is interfering with obstacles, prevent damage to the cutter, and prevent damage to the cutting blade during mowing. Also, the life and durability of the cutter can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a brush cutter.

FIG. 2 is an enlarged longitudinal sectional side view of a cutter portion of the brush cutter.

FIG. 3 is a plan view of a cutter.

FIG. 4 is a longitudinal sectional view of a cutter.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Brush cutter, 3 ... Engine which is a power source, 20 ... Cutter, 22 ... Cutting blade, 23 ... Annular convex part.

Claims (1)

[Claims] 1. A brush cutter in which a disk-shaped cutter is rotated by power to cut grass by rotation of the cutter, wherein the cutter has a circular saw shape having a cutting blade on an outer peripheral portion. A cutter for a brush cutter, wherein an annular convex portion is integrally provided on a lower surface thereof so as to protrude downward.