JPH0687701B2 - Power brush cutter over-rotation prevention device - Google Patents
Power brush cutter over-rotation prevention deviceInfo
- Publication number
- JPH0687701B2 JPH0687701B2 JP1107410A JP10741089A JPH0687701B2 JP H0687701 B2 JPH0687701 B2 JP H0687701B2 JP 1107410 A JP1107410 A JP 1107410A JP 10741089 A JP10741089 A JP 10741089A JP H0687701 B2 JPH0687701 B2 JP H0687701B2
- Authority
- JP
- Japan
- Prior art keywords
- cutting blade
- power
- output shaft
- power shaft
- shaft
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Landscapes
- Braking Arrangements (AREA)
- Harvester Elements (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 この発明は、草刈等に使用される動力刈払機において刈
刃の回転速度を許容値以下に保持する過回転防止装置に
関するものである。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an over-rotation prevention device that keeps the rotational speed of a cutting blade below a permissible value in a power brush cutter used for mowing or the like.
実開昭57-173524号公報は動力刈払機におけるブレーキ
装置を開示する。このブレーキ装置によれば、作業者
は、ブレーキレバーを手動操作することにより、ギヤ装
置の出力軸等が制動され、刈刃の回転速度が低下するよ
うになっている。Japanese Utility Model Laid-Open No. 57-173524 discloses a braking device for a power brush cutter. According to this brake device, an operator manually operates the brake lever to brake the output shaft of the gear device or the like, thereby reducing the rotation speed of the cutting blade.
このブレーキ装置は手動操作であり、刈刃に過回転が生
じたときに、刈刃の回転速度を自動的に低下させる機能
はない。This brake device is manually operated and does not have a function of automatically reducing the rotation speed of the cutting blade when the cutting blade is over-rotated.
請求項１の発明の目的は、刈刃が過回転となったとき、
刈刃の回転速度を自動的に低下させることができる動力
刈払機の過回転防止装置を提供することである。It is an object of the invention of claim 1 when the cutting blade is over-rotated,
An object of the present invention is to provide an over-rotation prevention device for a power brush cutter that can automatically reduce the rotation speed of a cutting blade.
請求項２の発明の目的は、さらに、動力刈払機における
過回転防止装置の搭載が有利となるようにすることであ
る。An object of the invention of claim 2 is to make it advantageous to mount an over-rotation preventing device in a power brush cutter.
この発明を、実施例に対応する図面の符号を使用して説
明する。The present invention will be described using the reference numerals of the drawings corresponding to the embodiments.
請求項１の動力刈払機（10）の過回転防止装置は、動力
軸（26）を介して伝達された回転動力により回転する刈
刃（18）と、動力軸（26）の半径方向へ変位自在に動力
軸（26）に取付けられ動力軸（26）と一体的に回転する
摩擦部材（48）と、この摩擦部材（48）を動力軸（26）
の方へ付勢する付勢部材（52）と、動力軸（26）の半径
方向に関して摩擦部材（48）より外側に配設され内面側
において摩擦部材（48）を圧接可能とされる静止部材
（24）とを有してなる。The over-rotation prevention device for a power brush cutter (10) according to claim 1, wherein the cutting blade (18) that is rotated by the rotational power transmitted through the power shaft (26) and the power shaft (26) are displaced in the radial direction. A friction member (48) that is freely attached to the power shaft (26) and rotates integrally with the power shaft (26), and this friction member (48) is the power shaft (26).
A biasing member (52) that biases the friction member (52) in the radial direction of the power shaft (26) and a stationary member that can be pressed against the friction member (48) on the inner surface side of the friction member (48). (24) and have.
請求項２の動力刈払機（10）の過回転防止装置では、静
止部材（24）は、操作桿（12）の先端部に取付けられて
内部にギヤ装置（16）を収容するギヤケース（24）であ
り、動力軸（26）はギヤ装置（16）の出力軸（26）であ
る。そして、刈刃（18）は出力軸（26）に一体回転的に
取付けられている。In the over-rotation prevention device for a power brush cutter (10) according to claim 2, the stationary member (24) is attached to the tip of the operating rod (12) to accommodate the gear device (16) inside the gear case (24). The power shaft (26) is the output shaft (26) of the gear device (16). The cutting blade (18) is integrally and rotatably attached to the output shaft (26).
請求項１の発明において、刈刃（18）の回転速度が許容
値以下であるとき、動力軸（26）の回転速度は低く、摩
擦部材（48）に生じる遠心力は小さい。この結果、摩擦
部材（48）は付勢部材（52）により静止部材（24）の内
面から離れており、摩擦部材（48）と静止部材（24）と
の間に摩擦力が生じず、動力軸（26）は、制動されるこ
となく、回転し、刈刃（18）の回転は制動されない。In the invention of claim 1, when the rotation speed of the cutting blade (18) is equal to or lower than the allowable value, the rotation speed of the power shaft (26) is low and the centrifugal force generated in the friction member (48) is small. As a result, the friction member (48) is separated from the inner surface of the stationary member (24) by the biasing member (52), and no frictional force is generated between the friction member (48) and the stationary member (24). The shaft (26) rotates without being braked, and the rotation of the cutting blade (18) is not braked.
これに対し、刈刃（18）の回転速度が許容値を超えて、
刈刃（18）の過回転が生じたとき、動力軸（26）の回転
速度は高く、摩擦部材（48）に生じる遠心力は大きい。
この結果、摩擦部材（48）は、付勢部材（52）に抗して
遠心力により動力軸（26）の半径方向外側へ変位し、静
止部材（24）の内面に圧接される。これにより、摩擦部
材（48）と静止部材（24）との間に大きな摩擦力が生
じ、動力軸（26）の回転は制動され、刈刃（18）の回転
速度は許容値以下へ低下する。On the other hand, the rotation speed of the cutting blade (18) exceeds the allowable value,
When the cutting blade (18) is over-rotated, the rotation speed of the power shaft (26) is high and the centrifugal force generated in the friction member (48) is large.
As a result, the friction member (48) is displaced outward in the radial direction of the power shaft (26) by the centrifugal force against the biasing member (52) and is pressed against the inner surface of the stationary member (24). As a result, a large frictional force is generated between the friction member (48) and the stationary member (24), the rotation of the power shaft (26) is braked, and the rotation speed of the cutting blade (18) is reduced to an allowable value or less. .
請求項２の発明では、摩擦部材（48）は、刈刃（18）の
支軸用の出力軸（26）と一体的に回転し、刈刃（18）の
過回転の発生時ではギヤケース（24）の内面に圧接され
る。In the invention of claim 2, the friction member (48) rotates integrally with the output shaft (26) for the spindle of the cutting blade (18), and when the cutting blade (18) is excessively rotated, the gear case ( It is pressed against the inner surface of 24).
以下、この発明を図面の実施例について説明する。 Hereinafter, the present invention will be described with reference to the embodiments of the drawings.
第３図は動力刈払機10の全体を概略的に示す斜視図であ
る。動力刈払機10は、長く延びる操作桿12と、この操作
桿12の上端部に結合するエンジン本体部14と、操作桿12
の下端部に結合するギヤ装置16と、このギヤ装置16の下
面側に配設されエンジン本体部14から操作桿12内の伝達
軸（図示せず）及びギヤ装置16のギヤ（図示せず）を経
て伝達される回転動力により回転される刈刃18とを備え
ている。ハンドル20は、左右へ張り出すように操作桿12
に固定され、スロットルレバー22は、ハンドル20の先端
部に取付けられ、エンジン本体部14のスロットル弁開度
を調整する。FIG. 3 is a perspective view schematically showing the entire power brush cutter 10. The power brush cutter 10 includes a long operating rod 12, an engine main body 14 coupled to an upper end of the operating rod 12, and an operating rod 12.
A gear device 16 coupled to the lower end of the gear device 16, a transmission shaft (not shown) in the operating rod 12 from the engine body 14 disposed on the lower surface side of the gear device 16 and a gear (not shown) of the gear device 16 The cutting blade 18 is rotated by the rotational power transmitted through the cutting blade 18. The handle 20 has a control rod 12
The throttle lever 22 is attached to the tip of the handle 20 and adjusts the throttle valve opening of the engine body 14.
第１図はギヤ装置16の下端部の内部構造図である。ギヤ
ケース24は、操作桿12の先端部に固定され、内部にベベ
ルギヤ等のギヤを収容している。出力軸26は、ギヤ装置
16の中心線に沿って延び、操作桿12内の伝達軸（図示せ
ず）からの回転動力を伝達され、ボールベアリング28に
より回転自在にギヤケース24に支持されている。Ｃワッ
シャ30は、ボールベアリング28の下端側においてギヤケ
ース24の内面に嵌着され、ボールベアリング28の脱落を
阻止している。出力軸26の先端部はスプライン嵌合用の
複数のキー溝31を形成され、巻き込み防止板32は、ギヤ
ケース24の下面側に固定され、半径方向へ張り出して、
草の茎等が刈刃18に中央部へ巻き込まれるのを防止す
る。出力軸26の軸方向へ上から順番に取付け部材34、上
側ボス36、下側ボス38及び安定板40が、配列され、出力
軸26のキー溝31にスプライン嵌合し、出力軸26と一体的
に回転するようになっている。ボルト42は、出力軸26の
先端面に螺合して、取付け部材34、上側ボス36、下側ボ
ス38及び安定板40をボールベアリング28の方へ締め付け
ている。過回転防止装置44は、取付け部材34を構成要素
として含み、ギヤケース24と出力軸26との間に設けられ
る。FIG. 1 is an internal structural diagram of the lower end portion of the gear device 16. The gear case 24 is fixed to the tip of the operating rod 12 and accommodates a gear such as a bevel gear inside. The output shaft 26 is a gear device.
It extends along the center line of 16, receives rotational power from a transmission shaft (not shown) in the operating rod 12, and is rotatably supported by the gear case 24 by a ball bearing 28. The C washer 30 is fitted to the inner surface of the gear case 24 on the lower end side of the ball bearing 28, and prevents the ball bearing 28 from falling off. A plurality of key grooves 31 for spline fitting are formed on the tip end of the output shaft 26, and the entrainment prevention plate 32 is fixed to the lower surface side of the gear case 24 and projects radially.
It prevents grass stems and the like from being caught in the center of the cutting blade 18. The mounting member 34, the upper boss 36, the lower boss 38, and the stabilizer 40 are arranged in order from the top in the axial direction of the output shaft 26, and are spline-fitted into the key groove 31 of the output shaft 26 to be integrated with the output shaft 26. It is designed to rotate. The bolt 42 is screwed onto the tip end surface of the output shaft 26 to tighten the mounting member 34, the upper boss 36, the lower boss 38, and the stabilizer 40 toward the ball bearing 28. The over-rotation prevention device 44 includes the mounting member 34 as a component, and is provided between the gear case 24 and the output shaft 26.
第２図は第１図の過回転防止装置44の詳細図である。取
付け部材34は、ギヤ装置16の出力軸26に貫通されてスプ
ライン嵌合する嵌合穴46を中心にもつ。一対のシュー48
は、所定の質量を有し、取付け部材34の両側に配設さ
れ、円弧状の外周側にはギヤケース24の円周内面に圧接
自在なライニング50が固着されている。各シュー48は引
張ばね52を介して取付け部材34に結合し、出力軸26（第
１図）の半径方向へ変位自在であるとともに、引張ばね
52により出力軸26の半径方向内側へ付勢されている。シ
ュー48は取付け部材34、したがって出力軸26と同一回転
速度で回転する。FIG. 2 is a detailed view of the over-rotation preventing device 44 of FIG. The mounting member 34 has a fitting hole 46, which penetrates the output shaft 26 of the gear device 16 and is fitted with a spline, as a center. A pair of shoes 48
Has a predetermined mass, is disposed on both sides of the mounting member 34, and has a lining 50 fixed to the inner circumferential surface of the gear case 24 so as to be press-contactable to the outer circumferential side of the arc. Each shoe 48 is coupled to the mounting member 34 via a tension spring 52, is displaceable in the radial direction of the output shaft 26 (Fig. 1), and has a tension spring.
The output shaft 26 is biased radially inward by 52. The shoe 48 rotates at the same rotational speed as the mounting member 34 and thus the output shaft 26.
実施例の作用について説明する。The operation of the embodiment will be described.
刈刃18の回転速度が許容値以下であるとき、出力軸26の
回転速度は低く、シュー48に生じる遠心力は小さい。こ
の結果、シュー48の外面側のライニング50は引張ばね52
によりギヤケース24の内面から離れており、シュー48と
ギヤケース24との間に摩擦力が生じず、出力軸26は、制
動されることなく、回転し、刈刃18の回転は制動されな
い。When the rotation speed of the cutting blade 18 is equal to or lower than the allowable value, the rotation speed of the output shaft 26 is low and the centrifugal force generated on the shoe 48 is small. As a result, the lining 50 on the outer surface of the shoe 48 has a tension spring 52
Is separated from the inner surface of the gear case 24, a frictional force is not generated between the shoe 48 and the gear case 24, the output shaft 26 rotates without being braked, and the rotation of the cutting blade 18 is not braked.
これに対し、刈刃18の回転速度が許容値を超えて、刈刃
18の過回転が生じているとき、出力軸26の回転速度は高
く、シュー48に生じる遠心力は大きい。この結果、シュ
ー48は引張ばね52に抗して遠心力により出力軸26の半径
方向外側へ変位し、シュー48のライニング50はギヤケー
ス24の内面に圧接される。これにより、シュー48のライ
ニング50とギヤケース24との間に大きな摩擦力が生じ、
出力軸26の回転は制動され、刈刃18の回転速度は許容値
以下へ低下する。On the other hand, if the rotation speed of the cutting blade 18 exceeds the allowable value,
When the over-rotation of 18 occurs, the rotation speed of the output shaft 26 is high and the centrifugal force generated on the shoe 48 is large. As a result, the shoe 48 is displaced radially outward of the output shaft 26 by centrifugal force against the tension spring 52, and the lining 50 of the shoe 48 is pressed against the inner surface of the gear case 24. This causes a large frictional force between the lining 50 of the shoe 48 and the gear case 24,
The rotation of the output shaft 26 is braked, and the rotation speed of the cutting blade 18 drops below the allowable value.
図示の実施例では、過回転防止装置44がギヤケース24内
に配設されているが、取付け部材34を操作桿12内の伝達
軸に取付け、シュー48のライニング50を操作桿12の内周
面に圧接することにより刈刃18の制動作用を得ることも
できる。In the illustrated embodiment, the over-rotation prevention device 44 is arranged in the gear case 24, but the mounting member 34 is attached to the transmission shaft in the operating rod 12, and the lining 50 of the shoe 48 is attached to the inner peripheral surface of the operating rod 12. It is also possible to obtain the braking action of the cutting blade 18 by pressing it against.
また、図示の実施例では、エンジンからの回転動力によ
り刈刃18が回転されるが、この過回転防止装置44は、電
動機の動力により刈刃18が回転される動力刈払機にも適
用可能である。Further, in the illustrated embodiment, the cutting blade 18 is rotated by the rotational power from the engine, but this over-rotation preventing device 44 is also applicable to a power brush cutter in which the cutting blade 18 is rotated by the power of the electric motor. is there.
請求項１の発明では、刈刃の過回転が生じると、摩擦部
材の回転速度が増大し、摩擦部材が静止部材の内面に遠
心力により圧接されて、動力軸が摩擦部材と静止部材と
の摩擦力により回転を自動的に制動される。したがっ
て、動力刈払機を使用した作業の安全性を向上すること
ができる。In the invention of claim 1, when the cutting blade is excessively rotated, the rotational speed of the friction member is increased, the friction member is pressed against the inner surface of the stationary member by centrifugal force, and the power shaft is separated from the friction member and the stationary member. Rotation is automatically braked by frictional force. Therefore, the safety of work using the power brush cutter can be improved.
請求項２の発明では、過回転防止装置は操作桿の先端部
のギヤ装置のギヤケース内に配設される。ギヤケース
は、刈刃の支軸用のギヤ装置の出力軸を包囲する静止部
材として既に存在し、支障なく径を増大可能であるの
で、動力刈払機における過回転防止装置の搭載部材をギ
ヤケース内とすることにより、搭載を円滑にかつ全体を
コンパクトにすることができる。According to the second aspect of the present invention, the over-rotation preventing device is arranged in the gear case of the gear device at the tip of the operating rod. The gear case already exists as a stationary member that surrounds the output shaft of the gear device for the cutting shaft of the cutting blade, and the diameter can be increased without any hindrance. By doing so, the mounting can be done smoothly and the whole can be made compact.
図面はこの発明の実施例に関し、第１図はギヤ装置の下
端部の内部構造図、第２図は第１図の過回転防止装置の
詳細図、第３図は動力刈払機の全体を概略的に示す斜視
図である。 10……動力刈払機、12……操作桿、16……ギヤ装置、18
……刈刃、24……ギヤケース（静止部材）、26……出力
軸（動力軸）、48……シュー（摩擦部材）、52……引張
ばね（付勢部材）。The drawings relate to an embodiment of the present invention. Fig. 1 is an internal structural view of a lower end portion of a gear device, Fig. 2 is a detailed view of an over-rotation preventing device of Fig. 1, and Fig. 3 is a schematic view of an entire power brush cutter. It is a perspective view which shows typically. 10 …… power brush cutter, 12 …… operating rod, 16 …… gear unit, 18
...... Mowing blade, 24 ...... Gear case (stationary member), 26 …… Output shaft (power shaft), 48 …… Shoe (friction member), 52 …… Tension spring (biasing member).
Claims (2)
により回転する刈刃（18）と、前記動力軸（26）の半径
方向へ変位自在に前記動力軸（26）に取付けられ前記動
力軸（26）と一体的に回転する摩擦部材（48）と、この
摩擦部材（48）を前記動力軸（26）の方へ付勢する付勢
部材（52）と、前記動力軸（26）の半径方向に関して前
記摩擦部材（48）より外側に配設され内面側において前
記摩擦部材（48）を圧接可能とされる静止部材（24）と
を有してなることを特徴とする動力刈払機の過回転防止
装置。1. A cutting blade (18) which is rotated by rotational power transmitted through a power shaft (26) and is mounted on the power shaft (26) so as to be displaceable in the radial direction of the power shaft (26). A friction member (48) that rotates integrally with the power shaft (26), a biasing member (52) that biases the friction member (48) toward the power shaft (26), and the power shaft ( 26) A motive power characterized by having a stationary member (24) arranged outside the friction member (48) in the radial direction and capable of press-contacting the friction member (48) on the inner surface side. Over-rotation prevention device for brush cutters.
端部に取付けられて内部にギヤ装置（16）を収容するギ
ヤケース（24）であり、前記動力軸（26）は前記ギヤ装
置（16）の出力軸（26）であり、前記刈刃（18）は前記
出力軸（26）に一体回転的に取付けられていることを特
徴とする請求項１記載の動力刈払機の過回転防止装置。2. The stationary member (24) is a gear case (24) which is attached to the tip of an operating rod (12) and accommodates a gear device (16) therein, and the power shaft (26) is the The output shaft (26) of a gear device (16), wherein the cutting blade (18) is integrally and rotatably attached to the output shaft (26). Over-rotation prevention device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1107410A JPH0687701B2 (en) | 1989-04-28 | 1989-04-28 | Power brush cutter over-rotation prevention device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1107410A JPH0687701B2 (en) | 1989-04-28 | 1989-04-28 | Power brush cutter over-rotation prevention device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02286006A JPH02286006A (en) | 1990-11-26 |
| JPH0687701B2 true JPH0687701B2 (en) | 1994-11-09 |
Family
ID=14458443
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1107410A Expired - Lifetime JPH0687701B2 (en) | 1989-04-28 | 1989-04-28 | Power brush cutter over-rotation prevention device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0687701B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5281178B2 (en) * | 2012-07-02 | 2013-09-04 | 網矢 ハル子 | Brake shoe |
| CN107736123A (en) * | 2017-11-24 | 2018-02-27 | 浙江长江机械有限公司 | Mower blade component |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5342523U (en) * | 1976-09-17 | 1978-04-12 |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5451283U (en) * | 1977-09-16 | 1979-04-09 |
-
1989
- 1989-04-28 JP JP1107410A patent/JPH0687701B2/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5342523U (en) * | 1976-09-17 | 1978-04-12 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02286006A (en) | 1990-11-26 |
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