JP2003310028A - Bush cutter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bush cutter having a reduced exhausted feeling of the hands of an operator for handling a lever for a throttle operation. <P>SOLUTION: The bush cutter with which a throttle operation is linked to the release of a damping device for controlling the idling of a reaping blade has a shaking member which is laid in the middle of a throttle wire extending between the lever for the throttle operation and a carburetor and is shaken around a first pivot by handling the lever for the throttle operation. The bush cutter has a lever for another operation for carrying out the operation different from the throttle operation, a pulley which is pivoted on a second pivot arranged above the first pivot for the shaking member and a tensile elastic member for energizing the shaking member to an initial position. The tensile elastic member is installed in the lateral direction between the first pivot and the second pivot. When the shaking member is shaken from the initial position to a shaking position, the shaking member is shaken from a separation position separated from the first pivot around one end to an adjoining position close to the first pivot. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brush cutter for cutting grass and the like, and more particularly to a brush cutter in which the throttle operation of a carburetor and the release of a braking device for controlling idling of a cutting blade are interlocked. .

[0002]

2. Description of the Related Art A brush cutter for cutting grass, which is driven by an internal combustion engine such as a small air-cooled two-cycle gasoline engine, has been conventionally known, which has a braking device for controlling idling of a cutting blade. For example, Japanese Patent Laid-Open No.
There is a brush cutter disclosed in Japanese Patent Laid-Open No. 1-196648. The braking device of the brush cutter has a friction member arranged around a centrifugal clutch clutch drum for transmitting the motion of the internal combustion engine to the cutting blade. Further, the brush cutter is swingable between a braking position where one end of the friction member is connected and a pressing position where the friction member is pressed against the clutch drum and a release position where the friction member is separated from the clutch drum. It has a rocking member. Further, a tension spring for urging the friction member to the braking position is attached to the swing member.
A throttle wire extending to the brake release lever is attached to the swing member. When the operator operates the brake release lever, a tensile force is applied to the throttle wire, and the swing member swings against the tensile force of the tension spring. Along with this, the friction member moves from the braking position to the release position.

[0003]

In such a brush cutter, an operator needs to work while holding the brake release lever in order to hold the brake device in a released state during the brush cutting operation. is there. Since the spring force of the tension spring acts on the swinging member, the force of the tension spring always acts on the hand of the operator. Is very tired. Therefore, an object of the present invention is to provide a brush cutter in which the operator who operates the operating lever is less tired.

[0004]

SUMMARY OF THE INVENTION The above object of the present invention is a brush cutter in which the throttle operation and the release of a braking device for controlling the idling of the cutting blade are interlocked, and a throttle operating lever and a carburetor are provided. A throttle wire extending between the two, and a swinging member that is interposed in the middle of the throttle wire and swings about the first pivot axis by the pulling force of the throttle wire by operating the throttle operating lever. The throttle wire includes a first wire portion extending between the throttle operating lever and the swing member, and a second wire portion extending between the swing member and the carburetor. The first operation transmission path from the throttle operation lever to the carburetor is configured by these, and the braking device is located at the initial position of the swing member. The cutting blade is prevented from idling, and the braking is released at the swing position. Further, another operation lever for performing an operation different from the throttle operation, and the first member on the swing member. A pulley pivotally mounted on a second pivot arranged at a position spaced from the pivot, the second wire portion extending through the pulley between the carburetor and the separate operating lever. A second operation transmission path different from the first operation transmission path is configured by these, and one end is attached to the body housing and the other end is attached to the swing member. The elastic tension member has an elastic tension member for urging the rocking member to the initial position, and the elastic tension member includes the first pivot shaft and the first pivot shaft when the plane in which the rocking member rocks is viewed in a plan view. Disposed laterally across the pivot, and The member is moved from the initial position to the swinging position, and is moved from the initial position to the swinging position. This can be achieved by a brush cutter characterized by swinging to a close position.

In the present invention, a first operation transmission path through which an operation of the throttle operating lever is transmitted to the carburetor to open and close (the throttle valve of) the carburetor,
Two operation transmission paths, which are the second operation transmission path different from the first operation transmission path, in which the operation of the separate operation lever acts only on the second wire portion, are provided. More specifically, in the first operation transmission path, when the throttle operating lever is operated, a tensile force is applied to the first wire portion, and the swing member resists the tensile force of the elastic tension member. Is pulled to swing from the initial position to the swing position, the pulling force applied to the second wire portion is transmitted to the throttle valve, and the throttle valve changes the operation amount of the throttle operating lever. Accordingly, the braking device is released and the braking device is released. In addition,
When the separate operation lever is operated in the initial position, only the second wire portion is pulled and the throttle valve is opened to a position suitable for starting the internal combustion engine.

With the swinging motion of the swinging member from the initial position to the swinging position, the elastic tension member has the one end between the first pivot shaft and the second pivot shaft as a center. , Oscillating from a spaced position away from the first pivot to a close position proximate to the first pivot, thereby extending the elastic tension member along with the vertical distance to the line of tension of the elastic tension member. The amount changes.

Since the force for operating the throttle operating lever is given through the first wire portion connected to the swing member, the force applied to the swing member by the elastic tension member varies. Change. The value of the moment M of force by the elastic tension member is obtained by the following formula. M = F · r = k · x · r where F: tensile force by the elastic tension member k: elastic coefficient of the elastic tension member x: elongation amount of the elastic tension member r: up to the action line of force of the elastic tension member The vertical distance (the vertical distance from the first axis to the axis of the elastic tension member).

Before and after the swing of the elastic tension member, since x and r change, the magnitude of the moment M of force also changes. However, the elastic tension member has the first pivot axis and the second pivot axis. Is laterally arranged between the first and second pivots, and moves between the first pivot axis and the second pivot axis, so that the change in the extension amount x of the elastic tension member is relatively small, and The distance r is also very small because the elastic tension member moves from the separated position separated from the first pivot to the close position. Therefore, the moment M of the force also becomes small after the swinging of the swinging member. Therefore, it is possible to reduce the fatigue of the hand of the worker who continues to hold the throttle operating lever during work.

Further, in the embodiment of the present invention, the first pivot axis and the second pivot axis project from the main body portion of the swing member toward the inside of the machine body housing, and the elastic tension member is provided. Are arranged in a space between the first pivot and the second pivot. Therefore, since the elastic tension member is arranged using the space, the housing can be downsized as a whole, and the brush cutter can be downsized.

[0010]

DETAILED DESCRIPTION OF THE INVENTION Referring to the accompanying drawings,
An embodiment of the brush cutter according to the present invention will be described. FIG. 1 is an overall view of the brush cutter according to the present embodiment. In addition, FIG. 2 and FIG. 3 show II-II (III
FIG. 6 is a sectional view taken along the line III-III) showing an initial position state and a swinging position state of the internal structure of the main body of the brush cutter according to the present embodiment. In the brush cutter 2 according to the present embodiment, the throttle operation and the release of the braking device 60 that controls the idling of the cutting blade 8 are interlocked. The structure will be described in detail below.

As shown in FIG. 1, the brush cutter 2 basically has an internal combustion engine 10 such as a small air-cooled two-stroke gasoline engine provided at the rear end, and a straight line extending forward from the internal combustion engine 10. It has an operating rod 6 and a cutting blade 8 provided at the tip of the operating rod 6. Further, a transmission shaft 12 for transmitting the rotational power from the internal combustion engine 10 to the cutting blade 8 extends straight inside the operating rod 6.
In addition, a U-shaped handle portion 14 is provided at an intermediate portion of the operating rod 6. A throttle operating lever 18 is provided on the right grip portion 16 of the handle portion 14.

A centrifugal clutch 22 (see FIG. 4) is interposed between the internal combustion engine 10 and the transmission shaft 12. The centrifugal clutch 22 includes a circular disc-shaped clutch drum 24 (see FIG. 2) having a peripheral wall portion 24a, and a centrifugal force generated by rotation of the crankshaft 10b of the internal combustion engine 10 causes the peripheral wall portion 24a of the clutch drum 24 to rotate. A shoe member 23 (see FIG. 4) that is pressed against the inner peripheral surface and transmits the rotation to the clutch drum 24. On the outer surface side of the clutch drum 24, a friction member 26 of a braking device 60 that is pressed against the outer peripheral surface of the peripheral wall portion 24a to suppress rotation is provided. More specifically, the friction member 26 is composed of a brake band 26 extending along the outer peripheral surface of the peripheral wall portion 24a. The brake band 26 is movably provided between a braking position (shown in FIG. 2) clamped around the outer peripheral surface of the peripheral wall portion 24a and a relaxed release position (shown in FIG. 3). There is. More specifically, one end 2 of the brake band 26
6a is locked in the housing 10a of the internal combustion engine 10 that constitutes the airframe housing, and the other end 26
b is the second connecting point 30 of the swinging member 30, as described later.
B is connected to the peripheral wall 24a of the clutch drum 24 by the swinging motion of the swinging member 30.

The carburetor 50 of the internal combustion engine 10 is located above and to the side of the clutch drum 24 in a state parallel to the rotation axis O of the clutch drum 24, that is, in the state shown in FIG. positioned.

Further, the brush cutter 2 according to the above embodiment is
As shown in FIG. 2, a throttle wire 28 including a Bowden cable extending between the throttle operating lever 18 and the carburetor 50, and the throttle wire 28.
And the swing member 30 that swings by the pulling force of the throttle wire 28. The throttle wire 28 extends between the first wire portion 29 extending between the throttle operating lever 18 and the swing member 30, and between the swing member 30 and the carburetor 50 (throttle valve thereof). A second wire portion 32,
It is composed of. These constitute a first operation transmission path P ₁ from the throttle operation lever 18 to the carburetor 50. More specifically, one end of the first wire portion 29 of the throttle wire 28 is connected to the throttle operating lever 18, and the other end is
It is connected to the first connection point 30 a of the swing member 30. The first wire portion 29 is the housing 10
The vaporizer 5 is attached to the clutch drum 24 in a.
It extends vertically in the lateral space opposite to 0.

As shown in FIG. 2, the swing member 30 is
An intermediate portion of the storage space in the housing 10a above the clutch drum 24 is pivotally fixed to the housing 10a at a first pivot shaft 39. The swinging member 30 has a first connecting point 30a arranged laterally on the opposite side of the carburetor 50 around the first pivot 39 and a second connecting point 3 arranged below.
0b, and the pulley 34 rotatably provided on the second pivot 35 arranged above the first pivot 39. The rocking member 30 has a fan-shaped portion in the upper portion and a bar-shaped portion extending in the lower portion in the lower portion, and has a substantially ginkgo leaf shape as a whole. The first connection point 30a is located near the side edge of the fan-shaped portion. The pulley 34 is located near the upper corner, and the carburetor 5 is
It is located to the side of 0. Further, the second connecting point 30b is located at the lower end of the rod-shaped portion.

The oscillating member 30 is urged to the initial (braking) position B by a first tension spring 38 including a coil spring or the like as an elastic tension member for urging the oscillating member 30 to the initial position B shown in FIG. Has been done. One end 38a of the first tension spring 38 is attached to the housing 10a, and
The other end 38b is attached to the swing member 30. The first tension spring 38 traverses between the first pivot shaft 39 and the second pivot shaft 35 when the plane in which the swing member 30 swings is viewed in plan (see FIGS. 2 and 3). It is arranged horizontally.

FIG. 4 is a partial sectional view taken along the line IV-IV shown in FIG. 1, showing the internal structure of the main body of the brush cutter according to the present embodiment. As shown in FIG. 4, the first pivot 3
9 and the second pivot 35 project from the main body of the swinging member 30 toward the inside of the housing 10a, and the tension spring 38 connects the first pivot 39 and the second pivot 35 with each other. It is located in the space between.

Referring again to FIG. 2, in the brush cutter 2 according to the present embodiment, in order to facilitate starting of the internal combustion engine 10, for idle up operation for slightly opening the throttle valve at the time of starting. A lever 41 is provided as a separate operation lever by protruding outward from the housing 10a. Further, in the present embodiment,
A second swing arm member 42 that swings by the operation of the idle-up operation lever 41 is provided between the swing member 30 and the throttle valve. The second swing arm member 42 has a generally elongated shape in the vertical direction, and a pivot 42a is provided at the lower end thereof. The idle-up operation lever 41 provided outside the housing 10a is integrally connected to the pivot 42a. By operating the idle-up operation lever 41, the second swing arm member 42 moves between the initial position B shown in FIG. 2 and the swing position F shown in FIG. 3 about the pivot 42a. Swing with. The second swing arm member 42 is normally urged to the initial position by a throttle valve return spring (not shown) of the carburetor 50, but if necessary, it may be used as urging means. The second spring 45 may urge the initial position B.

A third connecting point 42b, which is a connecting point of the other end 32b of the second wire portion 32, is provided at the upper end of the second swing arm member 42. The one end 32a of the second wire portion 32 is connected to the throttle valve. The second wire portion 32 extends laterally from the throttle valve, is wound around the pulley 34 from the upper side to the lower side, and is deflected by being folded back in a U shape. The other end 32b is the second swing. It is connected to the third connection point 42b of the arm member 42. The second wire portion 32 extending from the idle-up operation lever 41 to the throttle valve constitutes the second operation transmission path P ₂ . The second operation transmission path P ₂ is operationally independent of the first operation transmission path P ₁ .

The brush cutter 2 according to the embodiment shown in FIG.
It works as follows. In the initial (braking) position B, the swing member 30, the pulley 34, and the second swing arm member 42 are in the positions shown in FIG. First, before starting the internal combustion engine 10, the idle-up operation lever 41 protruding to the outside of the housing 10a is pushed down and rotated to move the second swing arm member 42 from the position shown in FIG. Move to the position shown in 3 in the counterclockwise direction. Due to the swing of the second swing arm member 42, the second wire portion 32 is slightly pulled, and the throttle valve is slightly opened from the idle position. In this state, the internal combustion engine 10 is started by the recoil starter 10c or the like. Subsequently, when the throttle operating lever 18 is squeezed and operated, the swing member 30 is swung from the initial position B to the swing position F shown in FIG. 3 via the throttle wire 28. The pulley 34 moves from the position shown in FIG. 2 to the position shown in FIG. In response to this, the throttle valve is opened to an opening degree corresponding to the grip amount of the throttle operating lever 18.

FIG. 5 is a schematic diagram for explaining the moment of force by the tension spring. The value of the moment M of the force by the tension spring 38 is obtained by the following equation, as described above. M = Fr = kxr Here, F: spring force of the tension spring 38 k: spring coefficient of the tension spring 38 x: extension amount of the tension spring 38 r: up to the line of action of the force of the tension spring 38 The vertical distance (the vertical distance from the first pivot 39 to the axis of the tension spring 38).

When the swing member 30 swings from the initial position B to the swing position F, as shown in FIG. 5, the tension spring 38 has the first pivot shaft 39 centered on the one end 38a. The separated position (shown by the solid line) separated from
From the state in which the free length L at A is stretched by x1 to the proximity position C (shown by a chain line), the state is further stretched by Δx. Before and after the swing of the tension spring 38, the x and the r change, but the tension spring 38 is arranged laterally between the first pivot 39 and the second pivot 35. Moreover, since the first pivot shaft 39 and the second pivot shaft 35 move between the first pivot shaft 39 and the second pivot shaft 35, the change Δx in the amount of extension x of the tension spring 38 is relatively small, and with respect to r, the tension spring 38 is Since it changes from r1 at the separated position A separated from the first pivot 39 to r2 at the close position C, it becomes very small. Therefore, the moment M of force is also very small. When the swinging member 30 is in the swinging position F, the tension spring 38 is close to the first pivot shaft 39, so the value of r, that is, r2, is very small. However, since the tension spring 38 requires an initial force for returning the swinging member 30 to the initial position B, r2 must be configured to be appropriately larger than zero. When the internal combustion engine 10 is started, the partial-up operation lever 41 may be released by manually operating in the opposite direction.

According to this embodiment, the tension spring 38 is
Is laterally disposed between the first pivot 39 and the second pivot 35 and is configured to move between the first pivot 39 and the second pivot 35. Therefore, the moment M of force becomes extremely small after the swinging of the swinging member 30. Therefore, it is possible to reduce the fatigue of the hand of the worker who continues to hold the throttle operating lever 18 during the work. The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the invention described in the claims, and those modifications are also included in the scope of the present invention. Needless to say.

In the braking device 60 of the brush cutter 2 according to the above embodiment, the braking member is constituted by the brake band 26 arranged around the outer peripheral surface of the clutch drum 24. The member may be another member that brakes the rotation of the clutch drum 24 and can be released by the swing motion of the swing member 30. Further, the tension spring 38 in the present embodiment may be any elastic member that applies a tensile force to the swing member 30, and may be a rubber material or another elastic member.

[0025]

As described above, according to the present invention, it is possible to provide a brush cutter in which the operator who operates the throttle operating lever feels little fatigue.

[Brief description of drawings]

FIG. 1 is an overall view of a brush cutter according to the present embodiment.

FIG. 2 is a sectional view taken along the line II-II in FIG. 1 showing an initial position state of the internal structure of the main body of the brush cutter according to the present embodiment.

FIG. 3 is a sectional view taken along the line III-III shown in FIG. 1, showing a swinging position of the internal structure of the main body of the brush cutter according to the present embodiment.

FIG. 4 is a partial cross-sectional view taken along the line IV-IV shown in FIG. 1, showing the internal structure of the main body of the brush cutter according to the present embodiment.

FIG. 5 is a schematic diagram illustrating a moment of force by a tension spring.

[Explanation of symbols]

2 Brush cutter 8 Cutting blade 10a Machine housing 18 Throttle operating lever 28 Throttle wire 29 First wire portion 30 Swing member 32 Second wire portion 34 Pulley 35 Second pivot 38 Tension spring (elastic tension member) 38a One end 38b The other end 39 1st axis 41 Idle-up operation lever (separate operation lever) 50 Vaporizer (throttle valve) 60 Braking device P ₁ First operation transmission path P ₂ Second operation transmission path B Initial position F Swing position A Separated position C proximity position

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Jun Kashima             Matsunosato, Kukizaki-cho, Inashiki-gun, Ibaraki 1 Independent Administrative Law             Human Forest Research Institute (72) Inventor Masaki Jinkawa             Matsunosato, Kukizaki-cho, Inashiki-gun, Ibaraki 1 Independent Administrative Law             Human Forest Research Institute (72) Inventor Tatsuya Sasaki             Matsunosato, Kukizaki-cho, Inashiki-gun, Ibaraki 1 Independent Administrative Law             Human Forest Research Institute F term (reference) 2B083 AA02 BA02 CA07 DA02 HA23

Claims (2)

[Claims] 1. A throttle operation and a cutting blade (8) idling are controlled.
Which is linked with the release of the braking device (60)
(2) Between the throttle operating lever (18) and the carburetor (50)
A throttle wire (28) extending between and the throttle
The slot is provided in the middle of the wire (28) and
The slot by operating the lever (18) for
The pulling force of the twin wire (28) causes the first pivot (3
And a swinging member (30) swinging about 9) as a center.
The throttle wire (28) is connected to the throttle
Between the operating lever (18) and the swing member (30)
A first wire portion (29) extending and the rocker member (3)
0) and the second wire portion extending between the vaporizer (50)
The minute (32) and the
Tottle operation lever (18) to the vaporizer (50)
First operation transmission path (P₁) Is configured,
The moving device (60) is the initial position of the rocking member (30).
In (B), the cutting blade (8) is prevented from idling and shaken.
Braking is released at the moving position (F), In addition, another operation for performing an operation different from the throttle operation
The lever (41) and the swing member (30) for the first
A second pivot located at a position spaced from the pivot (39)
A pulley (34) pivotally attached at (35),
The second wire portion (32) is routed through the pulley (34).
Then, the vaporizer (50) and the separate operation lever (41)
The first operation transmission by these.
Route (P ₁) Different from the second operation transmission path (P₂) Is composed
Has been done, Further, one end (38a) is attached to the body housing (10a),
The other end (38b) is attached to the swing member (30).
The swinging member (30) to the initial position (B).
An elastic tension member (38) for biasing the elastic tension member.
The tension member (38) causes the swinging member (30) to swing.
When viewed in plan, the first pivot (39) and the first axis (39)
Arranged laterally across the two pivots (35)
The elastic tension member (38) is connected to the swing member (3).
0) from the initial position (B) to the swing position (F)
The one end (38a) is moved to the center with the movement when swinging.
As a core, a separated position separated from the first pivot (39)
Proximity position close to the first pivot (39) from (A)
A brush cutter characterized by swinging to (C). 2. The first pivot (39) and the second pivot (35) from the body portion of the rocker member (30),
The elastic tension member (38) projects inwardly of the body housing (10a), and the elastic tension member (38) includes the first pivot shaft (3).
9. The brush cutter according to claim 1, characterized in that it is arranged in the space between 9) and the second pivot (35).