JP2000060262A - Bush cutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bush cutter capable of safely carrying out cutting works and making it possible to easily perform a work for exchanging a worn centrifugal blade with a new blade. SOLUTION: A rotation shaft 14 is disposed in a housing 13 fixed to the tip of an operation bar 11. A rotary disk 21 is rotatably supported on the spline portion 14a of the rotary shaft 14. Centrifugal blades 29 are supported on the rotary disk 21 through connection pins 28. A cover 36 is attached to the housing 13 through a support arm 35 so that the outermost portions of the revolution loci of the centrifugal blades 29-29 are surrounded using the lateral U-shaped portion K of the cover 36. A plurality of depressions for the approach of grasses to be cut are formed on the outer peripheral side of the cover 36. The rotary disk 21 is formed in a smaller outer diameter than the diameter of a circle C1 on the inner peripheral edge of the lower plate 36c. Thereby, the rotary disk 21 can be taken out together with the centrifugal blades 29.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brush cutter.

[0002]

2. Description of the Related Art As a conventional brush cutter, an actual utility model 3-858
The one shown in Japanese Patent Publication No. 20 has been proposed. This brush cutter supports a rotary shaft via a housing with respect to the tip of an operating rod grasped by an operator, and the circular saw is rotated by the rotary shaft. Further, the circular saw is almost entirely covered with an upper cover and a lower cover, and recesses are provided on both left and right sides of the upper cover and the lower cover so that a weed or the like to be cut can enter.

On the other hand, as a conventional brush cutter, Japanese Patent Application Laid-Open No. 51-5
The one disclosed in Japanese Patent No. 5086 is also proposed. In this brush cutter, the center parts of a pair of upper and lower rotating discs are fitted and fixed to a rotating shaft supported by a housing, and a centrifugal blade is interposed between both rotating discs to rotatably support them by a connecting pin. A protective cover is provided to cover the rotating disk from above and below.

[0004]

In the former brush cutter, since the circular saw is covered by the upper cover and the lower cover, it is possible to prevent the circular saw from hitting the circular saw even when there are empty bottles, empty cans and the like in the weeds. Therefore, the circular saw can be protected and the safety can be improved. However, this brush cutter has a problem that if a thin material to be mowed such as wire enters through the recesses provided in the upper and lower covers, the circular saw or the cover is damaged in an attempt to cut it. It was

On the other hand, in the latter brush cutter, since the centrifugal blade is tiltably connected to the rotary disk, when an empty can, a wire or the like hits the centrifugal blade, the impact can be mitigated. However, since a pair of upper and lower protective covers are provided corresponding to the rotating disc, the centrifugal blade protrudes more than the outer peripheral edge of the cover when in use, and therefore the edge of the concrete, stone, or standing tree is cut by the centrifugal blade. Moreover, pebbles, empty cans, etc. may scatter and damage the workers' feet. Also, when replacing a worn centrifugal blade,
After removing the lower protective cover, it is necessary to remove the rotary disk with the centrifugal blade attached from the rotary shaft, which causes a problem that the replacement work is troublesome.

The present invention has been made by paying attention to the problems existing in such conventional techniques, and the purpose thereof is to minimize the possibility that the body directly touches the centrifugal blade,
Accidents due to scattering of pebbles, empty cans, wires, etc. can be prevented, and safety can be improved during mowing work.
An object of the present invention is to provide a brush cutter capable of preventing damage to the centrifugal blade and the cover.

Another object of the present invention is to provide a brush cutter capable of easily replacing the centrifugal blade in addition to the above object.

[0008]

In order to achieve the above object, according to the invention as set forth in claim 1, a housing is attached to the distal end portion of the operating rod, and the rotary shaft is projected downward from the housing to rotate the rotary shaft. A rotating disk is detachably fitted to the lower end of the shaft, and a plurality of centrifugal blades are connected to the outer peripheral portion of the rotating disk by a connecting pin so as to be tiltable along the plane of the rotating disk and detachably. The housing is provided with a cover for covering the tip edges of the centrifugal blades in the maximum protruding state, and a concave portion is formed on the outer periphery of the cover so that the object to be mowed can enter the swirl locus of the centrifugal blades.

According to a second aspect of the present invention, in the first aspect, the outer peripheral portion of the cover is provided with an upper plate portion, an outer peripheral plate portion, and a lower plate so as to cover the outermost peripheral portion of the turning locus of each centrifugal blade. A horizontal U-shaped portion is formed, and a predetermined gap is formed in the horizontal direction between the outer peripheral edge of the rotating disk and the inner peripheral edge of the lower plate portion forming the horizontal U-shaped portion. With the centrifugal blade on the rotary disk retracted to the non-acting position, the rotary disk can be removed together with the centrifugal blade from the rotary shaft.

According to a third aspect of the present invention, in the second aspect, the inner peripheral edge of the lower plate portion is formed in an annular shape.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 6, a handle 12 is attached to the middle part of the operating rod 11 of the brush cutter. As shown in FIG. 1, a cylindrical housing 13 with a lid is connected downward to the tip of the operating rod 11 so that the lower end is opened. In the housing 13, a rotary shaft 14 is rotatably supported by radial ball bearings 15 at a predetermined position.

The rotary shaft 14 is a drive shaft 16 penetrating the inside of the operating rod 11, a drive bevel gear 17A provided at the tip of the drive shaft 16, and a driven bevel gear provided on the rotary shaft 14 so as to mesh with the drive bevel gear 17A. It is rotated by 17B. The drive shaft 16 includes an engine 18 attached to a base end portion of the operating rod 11 shown in FIG.
Are connected via.

As shown in FIGS. 1 and 3, a disc-shaped rotating disk 21 is supported on the spline portion 14a of the rotating shaft 14. A hole 21a through which the spline portion 14a is loosely formed is formed at the center of the rotary disk 21. A flange portion 1 is provided at an intermediate portion of the rotary shaft 14.
4b is formed, and between the lower surface of the flange portion 14b and the upper surface of the rotary disk 21, a mounting plate 22 fitted to the spline portion 14a so as to be integrally rotatable is interposed. As shown in FIG. 1, a bulge 22a is integrally formed on the lower surface of the mounting plate 22, and the bulge 22a is fitted into the hole 21a of the rotary disk 21. The lower surface of the rotary disk 21 is also provided with a spline portion 14a.
The mounting plate 23, which is fitted so as to be able to rotate integrally, is in contact with. The mounting plate 23 includes a bolt 24 and a spring washer 2 screwed into the lower end surface of the spline portion 14a.
The rotary disk 21 is pressed against the lower surfaces of the rotary disk 21 and the bulge portion 22a by means of 5, and the rotary disk 21 is clamped and fixed between the rotary disk 21 and the upper mounting plate 22.

A protective ring 26 having a function as a flywheel and a function for protecting a connecting pin and a screw, which will be described later, is brought into contact with the lower surface of the rotary disk 21 near the outer periphery, and a plurality of screws 27 and nuts 27a are provided. Is fixed to the rotary disk 21 by tightening. The protection ring 2
6 and the rotary disc 21 are penetrated upward by a plurality of connecting pins 28 (three places in this embodiment), and each connecting pin 28-28 has a centrifugal blade 29-29 around the pin 28. It is tiltably supported along the surface. The centrifugal blade 29 is prevented from coming off the pin 28 from the nut 32 screwed into the threaded portion 28a of the connecting pin 28.

On the lower surface of the protection ring 26, annular projections 26a and 26b are concentrically formed by press molding. Heads of the screws 27 to 27, connecting pins 28 to 28
Is located between the two ridges 26a and 26b so that it does not project downward.

As shown by the solid line in FIG. 4, the centrifugal blade 29 has a rotary disk 21 which is rotated about its center O1.
The center of gravity W is moved to the outside of the center O2 of the connecting pin 28 by the centrifugal force. In the maximum protruding state of the centrifugal blade 29, the centrifugal blade 2 with respect to the straight line R connecting the centers O1 and O2.
The arcuate blade portions 29a and 29b of 9 are formed symmetrically. Further, the centrifugal blade 29 shown by the solid line in FIG.
When it is inverted by 180 degrees about the center O2 of the center of FIG.

The outer periphery of the housing 13 is shown in FIGS.
As shown in FIG.
A cover 31 that covers 9 is attached. This cover 31
The cover supporting cylinder 32 constituting the above is fitted to the outer peripheral surface of the housing 13 so that the vertical position thereof can be adjusted. Nuts 33 are welded and fixed at a plurality of locations on the outer peripheral surface of the cylinder 32, and cylinder up / down adjusting screws 34 are screwed into these nuts 33. Then, while the cylinder 32 is fitted to the desired height, the cylinder 32 is fastened and fixed to the housing 13 with the screw 34.

A plurality of support arms 35 to 35 are radially mounted on the outer peripheral surface of the cover supporting cylinder 32, and a cover portion 36 is welded to the tip ends of the arms 35 to 35 by spot welding.

The cover portion 36 is formed in a plane annular shape as shown in FIGS. 2, 3 and 5, and is laterally formed by an upper plate portion 36a, an outer peripheral plate portion 36b and a lower plate portion 36c as shown in the cross section of FIG. A U-shaped portion k is formed. Further, as shown in FIGS. 3 and 5, arcuate concave portions 36d to 36d are formed on the outer periphery of the cover portion 36.
Are formed at a plurality of locations. As shown in FIG. 5, the recesses 36d to 36d are symmetrically formed on both left and right sides.

As shown in FIG. 5, the circle C2 formed by the inner peripheral edge of the upper plate portion 36a of the cover portion 36 has a center O3 at a displacement point which is displaced forward from the rotation center O1 of the rotary shaft 14 by a predetermined distance. It is a circle. Also, the lower plate portion 36
A circle C1 formed by the inner peripheral edge of c is a circle centered on the rotation center O1 of the rotation shaft 14. Furthermore, FIG.
As shown in FIG.
It is formed slightly smaller than.

As shown in FIG. 6, the engine 18 provided at the base end portion of the operating rod 11 is composed of an engine body 41 and a fuel tank 42 mounted on the upper portion of the body 41. As shown in FIG. 7, a mounting cylinder portion 42a is integrally formed with the fuel tank 42. The cap 43 is screwed into the mounting cylinder portion 42a. An inner lid 44 is fitted inside the mounting cylinder portion 42a. A tapered oil-proof packing 45 is housed inside the inner lid 44, and an inner top surface thereof is formed into a conical sloped surface 45a having a smaller diameter toward the upper end, and an intake pin hole 45b and a steel ball 46 are formed at the inner top portion thereof. Is formed with a recess 45c through which

Therefore, when the engine 18 is turned upside down and the fuel tank 42 is turned upside down as shown in FIG. 8, the steel ball 46 enters the recess 45c of the inner lid 44 and closes the intake pin hole 45b. Therefore, the fuel in the fuel tank 42 is suppressed from leaking to the outside.

As shown in FIG. 6, the handle 12 is constructed by attaching a handle main body 51 formed by bending a cylindrical pipe to the outer peripheral surface of the operating rod 11 by a bracket 52. The handle body 51 is at the rear (engine 18
Side) and a first bending portion 51a, and a second bending portion 5 that is bent upward at the rear end portions of both the first bending portions 51a.
1b and a handle portion 51c bent forward so as to be continuous with the second curved portion 51b. Reference numeral 53 is a throttle lever of the engine 18.

Next, the operation of the brush cutter constructed as described above will be described. Now, when the engine 18 is started and the number of revolutions becomes higher than the set number of revolutions by the throttle lever 53, the clutch in the clutch box 19 is put into the engaged state, and the rotational movement of the engine 18 is driven by the drive shaft 16, the drive bevel gear 17A, and the driven bevel gear. It is transmitted to the rotating shaft 14 via 17B. Therefore, the rotary disc 21 is rotated within the cover portion 36, and at the same time, the rotary disc 21 is rotated.
Centrifugal blades 29 to 29 connected to each other via a connecting pin 28 are swung. At this time, the center of gravity W of the centrifugal blades 29 to 29 is outside the connecting pin 28, that is, the blade portion 29, as shown in FIG.
Since they are located near the tips of a and 29b, the centrifugal blades 29 to 29 are displaced by centrifugal force so that the blade portions 29a and 29b on the left and right sides are directed outward.

While the centrifugal blades 29 to 29 are rotated, when the cover portion 36 approaches, for example, the weeding start portion of the weeds, the weeds enter the recess 36d of the cover portion 36. It is cut by 29a. During the mowing operation, when wire or pebbles enter the recess 36d, pebbles or the like are caught between the cover portion 36 and the blade portion 29a. However, due to the reaction at this time, the centrifugal blade 2
Since 9 is separated from foreign matter such as pebbles around the connecting pin 28, the cover 36 or the centrifugal blade 29 is not damaged.

Next, the effects of the brush cutter constructed as described above will be listed together with the structure. (1) The centrifugal blade 29 is rotatably attached to the rotary disk 21 by the connecting pin 28, and the centrifugal blades 29 to 29 are covered by the cover portion 36 of the cover 31. Therefore, even if foreign matter such as pebbles enters the recess 36d of the cover 36, damage to the cover 36 and the centrifugal blade 29 can be prevented.

(2) As shown in FIG. 2, the lower plate portion 36c forming the lateral U-shaped portion K of the cover portion 36 is attached to the rotary disc 21.
A slight gap G is arranged outward from the outer peripheral edge of.
Therefore, the rotary disk 21 can be easily removed from the cover part 36 together with the centrifugal blade 29 by simply removing the bolt 24, and the centrifugal blades 29 to 29 can be easily replaced.

(3) The centrifugal blade 29 has a blade portion 29a which is symmetrical with respect to a radial straight line R passing through the rotation center O1 of the rotary disk 21 and the center O2 of the connecting pin 28,
29b was constructed. Therefore, when one of the blade portions 29a is worn, the rotary disc 21 is removed and the centrifugal blade 29 is removed.
By reversing upside down, the blade portion 29b can be newly used as a cutting blade.

(4) As shown in FIG. 2, the width and depth are increased stepwise as the recess 36d of the cover 36 moves from the apex of the outer periphery to the left and right. For this reason,
The recess 36d to be used can be selected according to the size of the material to be cut. Since the recess 36d at the most dangerous apex portion is the narrowest and shallowest, it is possible to enhance safety.

(5) Since the protective ring 26 is attached to the outer periphery of the rotary disc 21, the weight on the outer peripheral side of the rotary disc 21 becomes large, and the rotary disc 21 functions as a flywheel, so that it is slower than a conventional brush cutter. Work can be performed by rotation, and vibration and noise can be suppressed.

(6) Since the lower plate portion 36c of the cover portion 36 is connected in an annular shape, the operation in the horizontal direction is smoothly performed with respect to the ground, and the mowed grass is not wrapped around. (7) In the above-described embodiment, since the cover portion 36 is supported by the support arms 35 to 35 extending in three directions with respect to the housing 13, long grass does not directly contact the rotating disc 21 during the mowing work, It is possible to suppress wrapping such as.

(8) As shown in FIG. 5, the center O3 of the circle C2 at the inner peripheral edge of the upper plate portion 36a constituting the cover portion 36 is
The position of the center O1 of the circle C1 on the inner peripheral edge of the lower plate portion 36c is displaced forward. Therefore, the support arm 3 extending in three directions
Two arms 35, 35 located on the rear side among 5 to 35
It is possible to widen the welding area of the tip of the. If Yen C
Assuming that 2 is the same as the circle C1, the recess 36a is formed so as to become deeper toward the rear side, so that the arm 35 is formed.
It is not possible to increase the area of the tip welded part.

Further, the two arms 35, 3 located on the rear side
The length from the center O1 of 5 can be shortened, and the strength of the support structure of the cover portion 36 can be easily ensured. (9) Since the fuel leakage prevention packing 45 and the steel balls 46 are provided on the inner lid 44 of the cap 43 of the fuel tank 42, it is possible to prevent the fuel from leaking from the tank 42 when the engine body is tilted by 130 degrees or more. .

(10) The first bending portion 15a directed rearward and the second bending portion 5 directed upward on the handle main body 51.
1b and the handle portion 51c that points to the front are provided, so that the handle portion 51c of the handle is a support point, that is, the bracket 52.
Will be located behind the position of the engine 18
It is possible to stabilize the weight balance between the brush cutter and the brush cutter (rotating disk 21 side). Therefore, operability can be improved.

The above embodiment can be modified and embodied as follows. As shown in FIG. 9, for cutting soft grass or grass, the recess 36d is formed in a U shape that opens outward in the radial direction, and a plurality of recesses 3 are formed at the bottom of the recess 36d.
It is also possible to form 6e so as to open radially outward.

The shape of the centrifugal blade 29 may be a linear blade, a single blade, or a circular blade. In FIG. 5, the diameter of the circle C2 may be further reduced, and the center O3 of the circle C2 may be concentric with the center O1 of the circle C1.

In this case, since the length of the support arm 35 located in the front can be shortened, the support strength of the cover portion 36 can be further improved. Other technical ideas understood from the above embodiment will be described below.

(Technical idea 1) The brush cutter according to any one of claims 1 to 3, wherein each of the recesses is formed in an arc shape opening toward both left and right sides. (Technical idea 2) In any one of claims 1 to 3, each of the recesses is formed in a recessed shape that opens outward in the radial direction, and a plurality of recesses are further opened outward in the radial direction at the bottom of the recess. A brush cutter that is configured to do.

(Technical idea 3) In any one of claims 1 to 3, the centrifugal blade is arranged on the left and right with respect to a radial center line passing through the rotation center of the rotating disk and the tilting center of the centrifugal blade in a protruding state by centrifugal force. A brush cutter having blades formed in a symmetrical shape.

(Technical idea 4) The brush cutter according to any one of claims 1 to 3, wherein a protective ring having a function as a flywheel is attached to the rotary disc. (Technical idea 5) In any one of claims 1 to 3, the center O3 of the circle C2 at the inner peripheral edge of the upper plate portion 36a forming the cover portion 36 is the center O1 of the circle C1 at the inner peripheral edge of the lower plate portion 36c.
A bush cutter that is displaced forward of the position of.

(Technical idea 6) In any one of claims 1 to 3, the diameter of the circle C2 at the inner peripheral edge of the upper plate portion 36a constituting the cover portion 36 is the same as the diameter of the circle C1 at the inner peripheral edge of the lower plate portion 36c. A brush cutter that is smaller than the above and has both circles C1 and C2 concentric.

(Technical idea 7) An inner lid 44 having a vent hole 44a is housed in a mounting tubular portion 42a of a fuel tank 42, and a cap 43 is screwed onto the tubular portion 42a so as to cover the inner lid 44. Tapered oil-proof packing 4 inside lid 44
5, a fuel tank lid structure in which an intake hole 45b is formed at the top of an inverted conical taper slope 45a formed in the packing 45, and a sphere is housed between the bottom plate of the inner lid 44 and the packing 45.

(Technical idea 8) A handle main body 51 is attached to the middle of the operating rod 11 via a bracket 52, and a first curved portion 15a directed rearward, a second curved portion 51b directed upward, and the handle main body 51. An operation handle structure of a brush cutter provided with a handle portion 51c directed forward.

[0044]

Since the invention according to claim 1 is configured as described above, it is possible to enhance the safety during the cutting operation and prevent the centrifugal blade from being damaged.

Further, according to the invention described in claim 2, in addition to the effect of the invention described in claim 1, the centrifugal blade can be easily replaced.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a central portion of a brush cutter according to the present invention.

FIG. 2 is a plan sectional view showing a main part of the brush cutter.

FIG. 3 is an exploded perspective view showing a bush cutting portion of the bush cutter.

FIG. 4 is an enlarged plan view of a centrifugal blade.

FIG. 5 is a plan view of a cover part.

FIG. 6 is a perspective view showing the entire brush cutter.

FIG. 7 is an exploded cross-sectional view showing a lid structure of a fuel tank of an engine.

FIG. 8 is a partial cross-sectional view of the fuel tank in the opposite direction.

FIG. 9 is a plan view of a cover part showing another embodiment of the present invention.

[Explanation of symbols]

11 ... Operation rod, 12 ... Handle, 13 ... Housing, 1
4 ... Rotating shaft, 16 ... Drive shaft, 18 ... Engine, 21 ... Rotating disk, 26 ... Protective ring, 28 ... Connecting pin, 29
Centrifugal blade, 31 ... Cover, 32 ... Cover support cylinder, 35 ... Support arm, 36 ... Cover part, 36a ... Upper plate part, 36b ... Outer peripheral plate part, 36c ... Lower plate part, 36d ... Recessed part, K ... Side U-shaped part.

Claims (3)

[Claims] 1. A housing is attached to the tip of the operating rod,
The rotary shaft is projected downward from the housing, the rotary disc is detachably fitted to the lower end of the rotary shaft, and a plurality of centrifugal blades are tilted along the plane of the rotary disc by connecting pins on the outer peripheral portion of the rotary disc. The housing is provided with a cover that covers the distal edges of the centrifugal blades that are in the maximum protruding state, and is connected to the housing in a detachable manner. A brush cutter having a recess that can enter the inside. 2. The horizontal U-shape formed by an upper plate portion, an outer peripheral plate portion and a lower plate portion on the outer peripheral portion of the cover so as to cover the outermost peripheral portion of the turning trajectory of each centrifugal blade. Is formed, a predetermined gap is formed in the horizontal direction between the outer peripheral edge of the rotary disc and the inner peripheral edge of the lower plate portion forming the horizontal U-shaped portion, and the centrifugal blade on the rotary disc is A brush cutter configured such that the rotary disk can be removed together with a centrifugal blade from a rotary shaft in a state of retracting to a non-acting position. 3. The brush cutter according to claim 2, wherein an inner peripheral edge of the lower plate portion is formed in an annular shape.