JP3608981B2

JP3608981B2 - Riding lawn mower

Info

Publication number: JP3608981B2
Application number: JP15927299A
Authority: JP
Inventors: 和夫鮫島; 義和戸越; 善幸江崎
Original assignee: Kubota Corp
Current assignee: Kubota Corp
Priority date: 1999-06-07
Filing date: 1999-06-07
Publication date: 2005-01-12
Anticipated expiration: 2019-06-07
Also published as: JP2000342039A

Description

【０００１】
【発明の属する技術分野】
本発明は、左右一対の遊転自在な前車輪及び駆動自在な後車輪と、運転座席とを備える走行車体の前後輪間に芝刈り装置を連結してある乗用型芝刈機に関する。
【０００２】
【従来の技術】
上記乗用型芝刈機において、従来、たとえば図６に示すものがあった。
すなわち、前車輪１と後車輪２とを備える走行車体の前後輪間に、車体によって上下揺動自在に支持される前揺動リンク３１及び後揺動リンク３２を設け、前揺動リンク３１が一体揺動自在に備えているアーム部と、後揺動リンクが一体揺動自在に備えているアーム部とにわたって連動杆Ｒを連結するとともに、前揺動リンク３１及び後揺動リンク３２の遊端側をチェーンＣを介して芝刈り装置２０のモアーデッキ２１に連結したものがあった。
つまり、前揺動リンク３１又は後揺動リンク３２を揺動操作することにより、前揺動リンク３１と後揺動リンク３２とが連動杆Ｒによる連動作用のために連動して揺動し、芝刈り装置２０が走行車体に対して昇降するものでる。
【０００３】
【発明が解決しようとする課題】
従来、走行し始めたり、走行停止するなどの際、前揺動リンクや後揺動リンクを芝刈り装置に連結しているチェーンのために芝刈り装置が走行車体に対して前後や左右方向に揺れ動きやすくなっていた。このため、芝刈り装置が前後や左右に揺れ動いても前輪や後輪に当たらないように、前後輪の間隔を芝刈り装置の大きさの割りには大にする必要があった。
本発明の目的は、前揺動リンクや後揺動リンクの揺動操作によって芝刈り装置を昇降操作できながら、前後輪間隔を芝刈り装置の大きさの割りには狭くでき、さらに、芝刈り装置を昇降操作する機構や運転部を強度面や構造面で有利に得られる芝刈機を提供することにある。
【０００４】
【課題を解決するための手段】
請求項１による発明の構成、作用、効果はつぎのとおりである。
【０００５】
〔構成〕
左右一対の遊転自在な前車輪及び駆動自在な後車輪と、運転座席とを備える走行車体の前後輪間に芝刈り装置を連結してある乗用型芝刈機において、
前記走行車体の左右一対の車体フレーム部の一方と他方とに各別に上下揺動自在に支持される左右一対の前揺動リンク、前記左右一対の車体フレーム部の一方と他方とにわたって配設された回動自在な車体横向きの１本の回転支軸に一体回動するように支持された左右一対の後揺動リンクを備えるとともに、前記左右一対の前揺動リンクと左右一対の後揺動リンクを、それぞれ前記左右一対の車体フレーム部の上下幅間の位置を揺動軸芯として左右一対の車体フレーム部の左右方向横外側に配設し、前記左右一対の前揺動リンクの遊端側に前記芝刈り装置の前端側を、前記左右一対の後揺動リンクの遊端側に前記芝刈り装置の後端側をそれぞれ相対回動自在に連結し、昇降操作機構によって前記回転支軸に連結された左右一対の後揺動リンクを揺動操作することにより、左右一対の前揺動リンクを後揺動リンクと共に揺動させて芝刈り装置を走行車体に対して昇降操作するように構成してある。
【０００６】
〔作用〕
車体フレーム部と前揺動リンクと後揺動リンクと芝刈り装置とが四連リンク機構を構成する。これにより、前揺動リンクと後揺動リンクとの一方を車体フレーム部に対して揺動操作すれば、他方も連動して揺動し、芝刈り装置が走行車体に対して上昇したり下降する。しかも、芝刈り装置と揺動リンクとの連結部やその他の連結部における融通などに起因して芝刈り装置が車体フレーム部に対して前後や左右に揺れ動くことがあっても、その揺れ動きは従来の連結チェーンによる揺れ動きよりも小さくなるようにして、芝刈り装置を走行車体に昇降自在に連結できる。
【０００７】
走行車体の前揺動リンクを支持する部分は、運転者の足元付近に位置する。このため、左右の車体フレーム部の一方と他方とにわたって１本の支軸を支持させ、この支軸によって左右の前揺動リンクを支持させると、その支軸が足元の下方を車体横方向に通り、足置きスペースの形状が支軸のために複雑になりやすい。支軸の上方に床板を設ける場合でも、床板の上面形状が支軸のために複雑になりやすい。すなわち、足置きスペースや床面が足を置きにくいとか歩行しにくいなど使用しにくいものになりやすい。これに対し、左右の前揺動リンクが左右の車体フレーム部に各別に支持されるものだから、左の前揺動リンクのための支軸と、右の前揺動リンクのための支軸とを別々の支軸にして左右の車体フレーム部に各別に支持させ、足元や床板の下方を車体横方向に通る支軸を無くし、足置きスペースや床板を簡素な形状のものにしながら左右の前揺動リンクを車体に揺動自在に支持させられる。
【０００８】
左右の後揺動リンクが左の車体フレーム部と右の車体フレーム部とにわたって支持される回動自在な車体横向きの１本の回転支軸によって支持されるものだから、左右用別々の支軸で左の車体フレーム部と右の車体フレーム部とに各別に支持させるに比し、支軸が左と右の両側の車体フレーム部に支持されて後揺動リンクを強固に支持するようにしながら後揺動リンクを車体フレーム部に揺動自在に支持させられる。また、芝刈り装置を車体に対して昇降操作するための操作機構を回転支軸に連結するとともに、この回転支軸と左右一対の後揺動リンクが一体回動するように支持することにより、操作機構の操作力が回転支軸によって左右の後揺動リンクに伝達され、左の揺動リンクの動きと右の後揺動リンクの動きにズレが出ないようにしながら左右の後揺動リンクを一挙に揺動操作し、芝刈り装置を左右に傾斜するとかこじれたりする作動不良が発生しないようにスムーズに昇降させられる。回転支軸は運転座席の下方に位置するものだから、この回転支軸のための足置きスペースや床板が複雑な形状になることを防止しながらできる。
【０００９】
〔効果〕
したがって、前揺動リンク又は後揺動リンクを揺動操作することによって芝刈り装置を車体に対して昇降操作できる。しかも、芝刈り装置を従来よりも前後や左右に揺れ動きにくくして前後輪間隔を芝刈り装置の大きさの割りには小さくし、芝刈機全体を運転しやすいとか取扱やすいようにコンパクト化できる。
その上、運転部を足が置きやすいとか歩行しやすいなど使用しやすい状態に形成し、運転や乗り降りなどを行いやすくできる。さらに、後揺動リンクが車体に強固に支持されて芝刈り装置が強固に支持されるように耐久性の面でも優れた状態に得られるとともに、後揺動リンクの回転支軸に操作機構を連結するだけの比較的簡単な操作構造によって芝刈り装置をスムーズに昇降操作できるように構造面や操作面でも優れた状態に得られる。
【００１０】
請求項２による発明の構成、作用、効果はつぎのとおりである。
【００１１】
〔構成〕
請求項１による発明の構成において、前記左右一対の前揺動リンク及び後揺動リンクそれぞれと、前記芝刈り装置との一方に、芝刈り装置が揺動リンクに対して車体上下方向に移動することを許容する状態で揺動リンクと芝刈り装置とを連結する連結用長孔を備えてある。
【００１２】
〔作用〕
車輪が凹入部に入り込むとか芝刈り装置が隆起部に乗り上がるとかして芝刈り装置に押し上げ力が作用すると、芝刈り装置が連結用長孔のための揺動リンクに対して上昇し、芝刈り装置に地面側から掛かる衝撃力の緩和を図りながら作業できる。
【００１３】
〔効果〕
芝刈り装置が地面に衝突するなどしてそれに掛かる衝撃力が緩和され、芝刈り装置が前後や左右に揺れ動きにくいものでありながら、芝刈り装置の衝突による変形や破損が回避しやすくなる。
【００１４】
請求項３による発明の構成、作用、効果はつぎのとおりである。
【００１５】
〔構成〕
請求項１又は２による発明の構成において、前記回転支軸に昇降操作機構を連結するとともに、この昇降操作機構によって回転支軸を回転操作して左右一対の後揺動リンクを揺動操作することにより、左右一対の前揺動リンクを後揺動リンクと共に揺動させて芝刈り装置を走行車体に対して昇降操作するように構成してある。
【００１６】
〔作用〕
昇降操作機構を操作すると、回転支軸が回転して左右の後揺動リンクを両揺動リンクの動きにズレが出ないように一挙に揺動操作し、左右の前揺動リンクが芝刈り装置を介して後揺動リンクに連動していることによって後揺動リンクと共に揺動し、芝刈り装置が上昇したり下降するものである。
【００１７】
〔効果〕
昇降操作機構を後揺動リンクの回転支軸に連結するだけの比較的簡単な操作構造により、左右の後揺動リンク及び前揺動リンクを揺動操作して芝刈り装置をスムーズに昇降操作できる。
【００１８】
請求項４による発明の構成、作用、効果はつぎのとおりである。
【００１９】
〔構成〕
請求項１〜３のいずれか１項による発明の構成において、前記後揺動リンクに上昇付勢力を与える付勢手段を前記回転支軸に取り付けてある。
【００２０】
〔作用〕
芝刈り装置を上昇操作する際、付勢手段によって回転支軸を介して左右の後揺動リンクに上昇付勢力を与えてこの付勢力を上昇操作のための補助力とし、昇降操作機構によって加える上昇操作力の軽減化を図りながら上昇操作するものである。
【００２１】
〔効果〕
芝刈り装置を上昇操作するに当たり、付勢手段による付勢力を補助力として楽に上昇操作できる。
【００２２】
請求項５による発明の構成、作用、効果はつぎのとおりである。
【００２３】
〔構成〕
請求項１〜４のいずれか１項による発明の構成において、前記左右一対の前揺動リンクに、この前揺動リンクの車体フレーム部に対する連結点と、芝刈り装置に対する連結点との間隔を変更する長さ調節部を備えてある。
【００２４】
〔作用〕
左右の前揺動リンクが備えている長さ調節部を調節すると、各前揺動リンクの車体フレーム部に対する連結点と、芝刈り装置に対する連結点との間隔が変化し、芝刈り装置が後揺動リンクに対する連結点を揺動中心として車体に対して上下に揺動して芝刈り装置の車体に対する連結姿勢が変化する。
後揺動リンクに長さ調節部を備えさせ、この長さ調節部を調節して後揺動リンクの連結点間隔を調節することによっても、芝刈り装置が前揺動リンクに対する連結点を揺動中心として車体に対して上下に揺動し、芝刈り装置の車体に対する連結姿勢が変化するが、後揺動リンクの付近には後輪フェンダーなど、長さ調節部を操作する際の障害物になりやすい車体用部品が存在することが多く、調節操作が行いにくくなる。これに対し、前揺動リンクの場合にはその付近に存在する車体用部品が比較的少ないことから、長さ調節部を比較的容易かつ楽に操作して芝刈り装置の連結姿勢を調節できる。
【００２５】
〔効果〕
揺動リンクなどの製作や組付け誤差があるとか作業や格納上の都合とかによって芝刈り装置の連結姿勢に不具合が発生したり、連結姿勢の変更が必要になった場合、前揺動リンクの連結点間隔を変更して芝刈り装置の連結姿勢を所望のものに変更し、芝刈り装置をガタ付きやこじれのないようにスムーズに昇降するとか所望どおりの連結姿勢になって上昇するように調節できる。しかも、この調節を行うに当たり、長さ調節部を操作障害の受けにくい車体前部で容易かつ楽に操作して迅速に行える。
【００２６】
【発明の実施の形態】
図１及び図２に示すように、左右一対の前車輪１，１を前端部に遊転自在に備え、左右一対の後車輪２，２を後端側に駆動自在に備える走行車体１０の後部に、後車輪２の車軸芯よりもやや後側に位置するエンジン３を有する原動部を設け、前記走行車体１０の原動部よりも前側に、後車輪２の車軸芯よりもやや前側に位置する運転座席４、走行車体１０の前端側に支持される運転部床板６などを有する運転部を設け、前記走行車体１０の前後輪間に、モーアデッキ２１などを備える芝刈り装置２０をリンク式連結機構３０を介して昇降操作するように連結するとともに、左右後輪２，２の間に位置する伝動装置６から回転軸７を介して芝刈り装置２０に回転動力を伝達するように構成して、乗用型芝刈機を構成してある。
【００２７】
前記芝刈り装置２０には、前記モーアデッキ２１の他に、このモーアデッキ２１の内部に車体横方向に並んで位置する複数枚の回転刈り刃２２、モーアデッキ２１の前後側に取り付けたゲージ輪２３を備えてある。すなわち、リンク式連結機構３０の下降操作によって芝刈り装置２０を走行車体１０に対して下降作業状態にして車体を走行させる。すると、前記複数枚の回転刈り刃２２それぞれがエンジン３からの駆動力によって車体上下向きの軸芯まわりで回動し、ゲージ輪２３のモーアデッキ２１に対する取り付け高さ、あるいは、芝刈り装置２０の走行車体１０による吊り上げ高さによって決まる刈り高さで芝刈りを行っていく。
【００２８】
図２などに示すように、前記走行車体１０は、左右一対の車体前後向きの車体フレーム部１１ａ，１１ａ、この左右の車体フレーム部１１ａ，１１ａの前端部どうしを連結している前連結フレーム部１１ｂ、前記左右一対の車体フレーム部１１ａ，１１ａの後端部どうしを連結している後連結フレーム部１１ｃのそれぞれを備える前部車体フレーム１１と、この前部車体フレーム１１の前記後連結フレーム部１１ｃに前端側が連結している左右一対の車体前後向きの後部メインフレーム部１２ａ，１２ａ、及び、この左右の後部メインフレーム部１２ａ，１２ａの前端部どうしにわたって架設した座席支持フレーム部１２ｂなどを備える後部車体フレーム１２とによって構成してある。前部車体フレーム１１の左右の車体フレーム部１１ａは、車体上下方向視で両端側部分が車体前後向きになり、中間部分が車体横向きになるように屈曲成形した溝型板金材の端側部分で作成し、前部車体フレーム１１の後連結フレーム部１１ｃは、前記屈曲溝型板金材の中間部分で作成してある。後部車体フレーム１２の左右の後部メインフレーム部１２ａは、横幅方向が車体上下方向に、板厚方向が車体横幅方向にそれぞれなるように配置した平板形状の板金材で作成し、座席支持フレーム部１２ｂは、溝型や平板形状の板金材を組み合わせて作成してある。
【００２９】
前記左前輪１を遊転自在に支持する前輪支持体１３が一端側に、前記右前輪１を遊転自在に支持する前輪支持体１３が他端側にそれぞれ連結していることによって、左前輪１を一端側に、右前輪１を他端側にそれぞれ遊転自在に支持する前輪支持フレーム１４の中間部を、前記前部車体フレーム１１の前記前連結フレーム部１１ｂに連結してある。左前輪１の方の前記前輪支持体１３も、右前輪１の方の前記前輪支持体１３も、前輪支持フレーム１４のボス部１４ａに前車輪１の車軸芯１ａに対して水平方向に位置ずれしたキャスタ軸芯１３ａのまわりで自由に回動するように連結してある。これにより、左右前輪１，１は、前輪支持体１３及び前輪支持フレーム１４を介して走行車体１０の前端部に支持されているとともに、前輪支持フレーム１４に対する取り付け向きがキャスタ軸芯１３ａのまわりで自由に変化するキャスタ車輪になっている。
【００３０】
前記伝動装置６に、エンジン３の回転出力を左後輪２と右後輪２とに各別に伝達する一対の無段変速装置を備えてある。左後輪２に動力伝達する無段変速装置も、右後輪２に動力伝達する無段変速装置も、エンジン３によって駆動される油圧ポンプと、この油圧ポンプからの圧油によって駆動されて後輪２に回転動力を出力する油圧モータとで成る静油圧式の無段変速装置に構成してあり、油圧ポンプの斜板角を変更操作することにより、後輪２を前進側や後進側に駆動したり、動力伝達を断って後輪駆動を停止したりするとともに、前進側と後進側のいずれに駆動する場合も、伝達回動力を無段階に変速できる。すなわち、後輪２を前進側に駆動する場合も、後進側に駆動する場合も、無段階に変速して駆動できる。
【００３１】
図３などに示すように、左後輪２の前記無段変速装置の操作部に連係させた左走行レバー８ａと、右後輪２の前記無段変速装置の操作部に連係させた右走行レバー８ｂとを、運転部の運転座席４の前端側の左横側と右横側とに振り分けて設けてある。
すなわち、左走行レバー８ａを車体前後方向に揺動操作して無段変速装置を変速操作することによって左後輪２を前進側や後進側に駆動及び変速操作したり、停止操作し、右走行レバー８ｂを車体前後方向に揺動操作して無段変速装置を変速操作することによって右後輪２を前進側や後進側に駆動及び変速操作したり、停止操作する。このように左走行レバー８ａと右走行レバー８ｂを操作して左右後輪２，２を前進側又は後進側に等速度で駆動するとともに変速すると、左右前輪１，１が接地と後輪２による推進とのために直進前進又は直進後進の取り付け向きになり、車体が前進側又は後進側に直進するとともに変速走行する。そして、左右後輪２，２を前進側又は後進側に異なる速度で駆動したり、左右後輪２，２の一方を前進側で他方を後進側に駆動すると、左右前輪１，１が接地と後輪２による推進とのためにキャスタ軸芯１３ａのまわりで回動して横向き走行の取り付け向きになり、車体が左右後輪２，２の速度差や駆動方向によって決まる方向に、その速度差や駆動方向によって決まる旋回半径で向き変更する。
尚、左右の走行レバー８ａ，８ｂは、運転者が運転座席４に着座するとか、運転座席４から離れる際に座席４の前方を開放するように、図３に二点鎖線で示す如く運転座席４の前方から横外側に退避させられる。
【００３２】
図２などに示すように、前記リンク式連結機構３０は、走行車体１０の前記前部車体フレーム１１の前端部の両横外側に別れて位置する左右一対の前揺動リンク３１，３１と、前記前部車体フレーム１１の後端部の両横外側に別れて位置する左右一対の後揺動リンク３２，３２とによって構成してある。
【００３３】
図１、図２、図５などに示すように、左右一対の前揺動リンク３１，３１それぞれの基端側に筒体を溶接して作成したボス部３１ａを備えさせ、それぞれの遊端側にヨークを溶接して作成した連結部３１ｂを備えさせてある。そして、左側の前揺動リンク３１の基端側のボス部３１ａは、前部車体フレーム１１の前記左右一対の車体フレーム部１１ａ，１１ａのうちの左側の車体フレーム部１１ａの前端部に筒体を溶接して作成したボス部１１ｄに、両ボス部３１ａ，１１ｄを挿通する車体横向きの連結軸１５によって相対回動自在に連結してある。左側の前揺動リンク３１の遊端側の連結部３１ｂは、芝刈り装置２０の前記モーアデッキ２１の上面側の前端部に立設された左右一対の前連結ブラケット２４，２４のうちの左側の前連結ブラケット２４に、この連結ブラケット２４と連結部３１ｂとを挿通する車体横向きの前連結ピン３３によって相対回転自在に連結してある。右側の前揺動リンク３１の基端側のボス部３１ａは、前部車体フレーム１１の前記左右一対の車体フレーム部１１ａ，１１ａのうちの右側の車体フレーム部１１ａの前端部に筒体を溶接して作成したボス部１１ｄに、両ボス部３１ａ，１１ｄを挿通する車体横向きの連結軸１５によって相対回動自在に連結してある。右側の前揺動リンク３１の遊端側の連結部３１ｂは、芝刈り装置２０の前記モーアデッキ２１の前記左右一対の前連結ブラケット２４，２４のうちの右側の前連結ブラケット２４に、この連結ブラケット２４と連結部３１ｂとを挿通する車体横向きの前連結ピン３３によって相対回転自在に連結してある。左側の前揺動リンク３１を左側の車体フレーム部１１ａに連結している連結軸１５と、右側の前揺動リンク３１を右側の車体フレーム部１１ａに連結している連結軸１５とは別々の連結軸に作成してある。左右一対の後揺動リンク３２，３２それぞれの基端側に筒体を溶接して作成したボス部３２ａを備えさせ、それぞれの遊端側にヨークを溶接して作成した連結部３２ｂを備えさせてある。そして、左側の後揺動リンク３２の基端側のボス部３２ａは、前部車体フレーム１１の前記左右一対の車体フレーム部１１ａ，１１ａのうちの左側の車体フレーム部１１ａの後端部に筒体を溶接して作成したボス部１１ｅと、右側の車体フレーム部１１ａの後端部に筒体を溶接して作成したボス部１１ｅとにわたって相対回転自在に取り付けるとともに運転座席４の前端部の下方に位置するように配置した車体横向きの１本の回転支軸１６の左側の車体フレーム部１１ａのボス部１１ｅから車体横外側に突出する支軸端部に外嵌するとともに連結ボルトによって一体回転するように、かつ、抜け止めされるように係止させてある。左側の後揺動リンク３２の遊端側の連結部３２ｂは、芝刈り装置２０の前記モーアデッキ２１の上面側の後端部に立設された左右一対の後連結ブラケット２５，２５のうちの左側の後連結ブラケット２５に、この連結ブラケット２５と連結部３２ｂとを挿通する車体横向きの後連結ピン３４によって相対回転自在に連結してある。右側の後揺動リンク３２の基端側のボス部３２ａは、前記回転支軸１６の前記右側の車体フレーム部１１ａのボス部１１ｅから車体外側に突出する軸端部分に外嵌するとともに連結ボルトによって一体回転するように、かつ、抜け止めされるように係止させてある。右側の後揺動リンク３２の遊端側の連結部３２ｂは、芝刈り装置２０の前記モーアデッキ２１の前記左右一対の後連結ブラケット２５，２５のうちの右側の後連結ブラケット２５に、この連結ブラケット２５と連結部３２ｂとを挿通する車体横向きの後連結ピン３４によって相対回転自在に連結してある。
【００３４】
これにより、リンク式連結機構３０の左右一対の前揺動リンク３１，３１は、走行車体１０の左側の車体フレーム部１１ａの前端部と右側の車体フレーム部１１ａの前端部とに各別に別々の前記連結軸１５を支軸として上下揺動自在に支持されていて、芝刈り装置２０のモーアデッキ２１の前端側を前部車体フレーム１１に昇降自在に連結しており、左右一対の後揺動リンク３２，３２は、走行車体１０の左右一対の車体フレーム部１１ａ，１１ａの後端部どうしによって１本の回転支軸１６を介して上下揺動自在に支持されていて、芝刈り装置２０のモーアデッキ２１の後端側を前部車体フレーム１１に昇降自在に連結している。したがって、走行車体１０の前部車体フレーム１１と、前揺動リンク３１と、後揺動リンク３２と、芝刈り装置２０のモーアデッキ２１とが四連リンク機構を構成している。
【００３５】
図４に示すように、前記回転支軸１６の前記右側の車体フレーム部１１ａよりも車体内側に位置する部分に一体回転するように連結した扇型の支軸ギヤ４１と、この支軸ギヤ４１に噛み合っている扇型のレバーギヤ４２と、このレバーギヤ４２に一端側が一体回転自在に連結していてレバーギヤ４２を支持している支軸４３の他端側に基端部が一体回転自在に連結しているとともに運転部の右横側に位置する昇降レバー４４とにより、芝刈り装置２０を走行車体１０に対して昇降操作する昇降操作機構４０を構成してある。前記操作レバー４４がこの操作レバー４４の稈身方向に摺動自在に支持しているロックピン４５と、このロックピン４５が係脱する複数個の切欠き部４６ａを備えているとともに前記前部車体フレーム１１の車体フレーム部１１ａに支持されているロック部材４６とによって操作レバー４４を所定の操作位置に固定するロック機構を、前記昇降操作機構４０に備えさせてある。
【００３６】
前記回転支軸１６の長手方向での中心部に基端部が一体回動自在に連結している操作アーム４７の遊端側と、前記後部車体フレーム１２の左右の後部メインフレーム部１２ａ，１２ａどうしにわたって連結している連結フレーム１２ｃが支持するスプリング受け具４８とにわたってガススプリング４９を取り付けてある。このガススプリング４９は、前記スプリング受け具４８に一端側が相対回動自在に連結しているシリンダチューブ４９ａと、このシリンダチューブ４９ａに一端側が摺動自在に内嵌するとともに他端側が前記操作アーム４７に相対回動自在に連結しているシリンダロッド４９ｂとを備えるとともに、前記シリンダチューブ４９ａの内部に充填してあるガスなどを備えており、この充填ガスがシリンダロッド４９ｂをシリンダチューブ４９ａから突出する側に摺動付勢し、この付勢力により回転支軸１６を回転付勢することによって左右の後揺動リンク３２，３２を芝刈り装置２０が走行車体１０に対して上昇する側に揺動付勢している。芝刈り装置２０を走行車体１０に対して下降操作する際、ガススプリング４９のシリンダロッド４９ｂがシリンダチューブ４９ａに対して入り込む側に摺動操作される。これにより、ガススプリング４９は、芝刈り装置２０の下降操作を可能にする。
【００３７】
すなわち、芝刈り装置２０を走行車体１０に対して昇降操作するに当たり、操作レバー４４の頭部から突出しているロック解除ボタン４５ａを押し操作することにより、ロックピン４５がロック部材４６の切欠き部４６ａから抜け外れて長孔部４６ｂに入り込み、ロック機構がロック解除状態になる。このようにロック機構をロック解除状態に操作しながら、操作レバー４４を、前記支軸４３を回転自在に支持する部材に兼用してある前記ロック部材４６に対して支軸４３の軸芯まわりで揺動操作する。すると、このレバー操作力のためにレバーギヤ４２が支軸４３の軸芯まわりで回動し、支軸ギヤ４１がレバーギヤ４２によって回動操作されて回転支軸１６を回転操作することによって左右の後揺動リンク３２，３２を車体フレーム部１１ａに対して下降側や上昇側に揺動操作する。すると、左右の前揺動リンク３１，３１がモーアデッキ２１を介して後揺動リンク３２に連動していることから、後揺動リンク３２と共に後揺動リンク３２と同じ方向に揺動し、芝刈り装置２０が走行車体１０に対して上昇したり下降する。芝刈り装置２０を上昇操作する際、前記ガススプリング４９による上昇付勢力によって上昇操作が補助され、操作レバー４４に加える操作力を比較的軽く済ませながら操作できる。芝刈り装置２０が所定の上昇位置や下降位置になると、ロック解除ボタン４５ａの押し操作を解除し、ロックピン４５を操作レバー４４の内部に位置するロックバネ４５ｂの操作力によってロック部材４６の前記複数個の切欠き部４６ａのいずれか一つに入り込ませる。すると、ロック機構が操作レバー４４を芝刈り装置２０の重量によって下降側に操作されないように固定するロック作用状態になり、このレバーロックのために、芝刈り装置２０を操作した持ち上げ高さにロックできる。
【００３８】
図４及び図５に示すように、前記左右一対の前揺動リンク３１，３１それぞれの基端側に、長さ調節部３５を備えてある。この長さ調節部３５は、前揺動リンク３１のうちの前記ボス部３１ａを備える車体側リンク部にねじ筒体を溶接して作成したねじ筒部３５ａと、前揺動リンク３１のうちの前記連結部３１ｂを備える芝刈り側リンク部に備えさせたねじ軸部３５ｂとによって構成してある。すなわち、ねじ軸部３５ｂとねじ筒部３５ａとを相対回転させて、ねじ軸部３５ｂがねじ筒部３５ａに入り込んで連結する長さを調節することにより、前揺動リンク３１の長さを変更し、前揺動リンク３１の車体フレーム部１１ａに対する連結点としての前記連結軸１５の軸芯と、芝刈り装置２０のモーアデッキ２１に対する連結点としての前記前連結ピン３３の軸芯との間隔Ｄを変更する。前記ねじ軸部３５ｂには、前揺動リンク３１の調節した長さを振動などで変化しないように固定するロックナット３６を備えてある。
【００３９】
すなわち、左右の前揺動リンク３１，３１それぞれの長さ調節部３５を操作してそれぞれの前記連結点間隔Ｄを変更することにより、モーアデッキ２１が後揺動リンク３２に対する連結点を揺動中心として車体に対して上下に揺動し、芝刈り装置２０の車体に対する連結姿勢を調節できる。
【００４０】
図４に示すように、芝刈り装置２０のモーアデッキ２１が備える前記左右一対の前連結ブラケット２４，２４及び前記左右一対の後連結ブラケット２５，２５のそれぞれに連結用長孔２４ａ，２５ａを備えてある。各連結用長孔２４ａ，２５ａは、前記連結ピン３３，３４を摺動自在に入り込ませており、芝刈り装置２０が前揺動リンク３１や後揺動リンク３２に対して連結用長孔２４ａ，２５ａの長さによって決まるストローク範囲で車体上下方向に昇降することを許容しながら、モーアデッキ２１と前揺動リンク３１や後揺動リンク３２とを連結している。
【００４１】
これにより、前車輪１や後車輪２が地面の凹入部に入り込むとか芝刈り装置２０の前記ゲージ輪２３やモーアデッキ２１の前端側に備えてある障害物乗り越えローラ２６が隆起部などに乗り上がるとかして芝刈り装置２０に押し上げ力が作用しても、芝刈り装置２０が前連結ブラケット２４や後連結ブラケット２５の連結長孔２４ａ，２５ａのために前揺動リンク３１や後揺動リンク３２に対して上昇して芝刈り装置２０に地面側から掛かる衝撃力の緩和を図りながら作業できる。
【００４２】
〔別実施形態〕
前連結ブラケット２４や後連結ブラケット２５の方に連結用長孔２４ａ，２５ａを設けるに替え、前揺動リンク３１や後揺動リンク３２の連結部３１ｂの方に連結ピン３３，３４が摺動自在に入り込む連結用長孔を設けて実施してもよい。この場合も、芝刈り装置２０に地面側から操作力が作用した際、芝刈り装置２０が前揺動リンク３１や後揺動リンク３２に対して上昇し、芝刈り装置２０に掛かる衝撃力の緩和を図りながら作業できる。
【００４３】
前記ガススプリング４９に替え、コイルスプリングや、コイルスプリングとガススプリングとを併用したものを採用して後揺動リンク３２を芝刈り装置２０の上昇側に揺動付勢するように構成して実施してもよいのであり、これらガススプリング４９やコイルスプリングなどを総称して付勢手段４９と呼称する。
【図面の簡単な説明】
【図１】乗用型芝刈機全体の側面図
【図２】車体及び連結機構の平面図
【図３】運転部の正面図
【図４】連結機構及び昇降操作機構の側面図
【図５】連結機構の左側部分の平面図
【図６】従来の乗用型芝刈機全体の側面図
【符号の説明】
１前車輪
２後車輪
４運転座席
１０走行車体
１１ａ車体フレーム部
１６回転支軸
２０芝刈り装置
２４ａ，２５ａ連結用長孔
３５長さ調節部
４０昇降操作機構
４９付勢手段[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a riding lawn mower in which a lawn mower is connected between front and rear wheels of a traveling vehicle body that includes a pair of left and right freely rotatable front and rear wheels and a driving seat.
[0002]
[Prior art]
Conventionally, there is a conventional lawn mower as shown in FIG.
That is, a front swing link 31 and a rear swing link 32 that are supported by the vehicle body so as to be vertically swingable are provided between the front and rear wheels of the traveling vehicle body including the front wheel 1 and the rear wheel 2. The interlocking rod R is connected between the arm portion provided so as to be swingable integrally and the arm portion provided so that the rear swing link is freely swingable, and the free swing of the front swing link 31 and the rear swing link 32 is also achieved. There was one in which the end side was connected to the mower deck 21 of the lawn mower 20 via a chain C.
That is, by swinging the front swing link 31 or the rear swing link 32, the front swing link 31 and the rear swing link 32 swing in conjunction with each other due to the interlocking action by the interlocking rod R, The lawn mowing device 20 moves up and down with respect to the traveling vehicle body.
[0003]
[Problems to be solved by the invention]
Conventionally, when the vehicle starts running or stops traveling, the lawn mowing device is moved back and forth or left and right with respect to the traveling vehicle body because of the chain connecting the front swing link and the rear swing link to the lawn mower device. It was easy to shake. For this reason, it is necessary to increase the distance between the front and rear wheels relative to the size of the lawn mowing device so that the lawn mowing device does not hit the front or rear wheels even if the lawn mowing device swings back and forth or from side to side.
The object of the present invention is to reduce the distance between the front and rear wheels relative to the size of the lawn mowing device, while the lawn mowing device can be moved up and down by swinging the front swinging link and the rear swinging link. An object of the present invention is to provide a lawn mower that can advantageously obtain a mechanism and an operating unit for raising and lowering the apparatus in terms of strength and structure.
[0004]
[Means for Solving the Problems]
The configuration, operation, and effect of the invention according to claim 1 are as follows.
[0005]
〔Constitution〕
In a riding lawn mower in which a lawn mower is connected between front and rear wheels of a traveling vehicle body that includes a pair of left and right free-wheeling front and rear wheels that can be driven, and a driving seat,
A pair of left and right front swing links supported on one and the other of the pair of left and right body frame portions of the traveling vehicle body so as to be swingable up and down separately, and disposed between one and the other of the pair of left and right body frame portions. A single rotating support shaft that can be turned horizontally Supported to rotate integrally A pair of left and right rear swing links are provided, and the pair of left and right front swing links and the pair of left and right rear swing links are respectively left and right with the position between the vertical widths of the pair of left and right body frame portions as the swing axis. A pair of vehicle body frame portions are disposed laterally laterally outside, the front end side of the lawn mower device is on the free end side of the pair of left and right front swing links, and the free end side of the pair of left and right rear swing links. The rear end side of the lawn mower is connected to each other so as to be relatively rotatable. The lawn mowing device is moved by swinging the pair of left and right rear swing links connected to the rotary support shaft by the lifting operation mechanism so that the pair of left and right front swing links are swung together with the rear swing link. Configured to move up and down with respect to the vehicle body It is.
[0006]
[Action]
The vehicle body frame portion, the front swing link, the rear swing link, and the lawn mowing device constitute a four-link mechanism. As a result, if one of the front swing link and the rear swing link is swung with respect to the vehicle body frame portion, the other swings in conjunction with each other, and the lawn mower moves up or down with respect to the traveling vehicle body. To do. Moreover, even if the lawnmower swings back and forth or left and right with respect to the vehicle body frame due to the connection between the lawnmower and the swing link and other joints, the swinging motion is conventional. The lawn mowing device can be connected to the traveling vehicle body so as to be able to move up and down in such a manner that the lawn mowing device becomes smaller than the swinging motion of the connecting chain.
[0007]
The portion of the traveling vehicle body that supports the front swing link is located near the driver's feet. For this reason, when one support shaft is supported over one and the other of the left and right body frame portions, and the left and right front swing links are supported by the support shaft, the support shaft extends in the lateral direction of the vehicle body under the feet. As you can see, the shape of the footrest space tends to be complicated due to the support shaft. Even when a floor plate is provided above the support shaft, the top surface shape of the floor plate tends to be complicated due to the support shaft. That is, the footrest space and the floor surface are likely to be difficult to use, such as difficult to place feet or to walk. On the other hand, since the left and right front swing links are respectively supported by the left and right body frame parts, the left front swing link and the right front swing link Are supported separately on the left and right body frame parts, and the support shaft that passes under the feet and the floor plate in the lateral direction of the vehicle body is eliminated. The swing link is swingably supported by the vehicle body.
[0008]
Since the left and right rear swing links are supported by a single rotation support shaft that is supported by the left and right body frame portions and that can be rotated horizontally. Compared to supporting the left and right body frame parts separately, the support shafts are supported by the left and right body frame parts so that the rear swing link is firmly supported. The swing link is swingably supported on the body frame portion. In addition, an operation mechanism for raising and lowering the lawn mowing device with respect to the vehicle body is connected to the rotary spindle. In addition, the rotating support shaft and the pair of left and right rear swing links are supported so as to rotate integrally. As a result, the operating force of the operating mechanism is transmitted to the left and right rear swing links by the rotation support shaft, and the left and right rear swing links are moved so that there is no deviation between the left swing link and the right rear swing link. The swing link can be swung up and down smoothly so as not to cause a malfunction that may be caused when the lawnmower is tilted to the left or right. Since the rotating support shaft is located below the driver's seat, it is possible to prevent the footrest space for the rotating support shaft and the floor board from becoming a complicated shape.
[0009]
〔effect〕
Therefore, the lawnmower can be lifted and lowered with respect to the vehicle body by swinging the front swing link or the rear swing link. Moreover, the lawn mower is less likely to swing back and forth and left and right than before, and the distance between the front and rear wheels is made smaller than the size of the lawn mower so that the entire lawn mower can be easily operated and handled.
In addition, the driving part can be formed in a state that is easy to use, such as easy to put on a foot or to walk, so that driving and getting on and off can be performed easily. Furthermore, the rear swing link is firmly supported by the vehicle body, and the lawnmower is firmly supported, so that the durability can be improved and an operation mechanism is provided on the rotation support shaft of the rear swing link. It is possible to obtain an excellent structure and operation surface so that the lawnmower can be lifted and lowered smoothly by a relatively simple operation structure that is simply connected.
[0010]
The structure, operation, and effect of the invention according to claim 2 are as follows.
[0011]
〔Constitution〕
In the configuration of the invention according to claim 1, the lawnmower moves in one of the pair of left and right front swing links and the rear swing link and the lawn mowing device in the vertical direction of the vehicle body with respect to the swing link. A long slot for connection is provided for connecting the swing link and the lawn mower in a state that allows this.
[0012]
[Action]
When a pushing force is applied to the lawn mower, such as when a wheel enters a recessed part or the lawn mower rides on a raised part, the lawn mower rises with respect to the swing link for the connecting long hole, and the lawn mower Work can be done while reducing the impact force applied to the device from the ground side.
[0013]
〔effect〕
The impact force applied to the lawnmower when it collides with the ground is alleviated, and the lawnmower is less likely to swing back and forth and from side to side, but it is easy to avoid deformation and breakage due to the collision of the lawnmower.
[0014]
The structure, operation, and effect of the invention according to claim 3 are as follows.
[0015]
〔Constitution〕
In the configuration of the invention according to claim 1 or 2, a lifting operation mechanism is coupled to the rotating support shaft, and the rotating support shaft is rotated by the lifting operation mechanism to swing the pair of left and right rear swing links. Thus, the pair of left and right front swing links is swung together with the rear swing link so that the lawnmower is moved up and down with respect to the traveling vehicle body.
[0016]
[Action]
When the lifting mechanism is operated, the rotation support shaft rotates and the left and right rear swing links are swung at once so that the movement of both swing links does not shift. By interlocking with the rear swing link via the device, it swings with the rear swing link, and the lawnmower moves up and down.
[0017]
〔effect〕
The lawn mowing device can be moved up and down smoothly by swinging the left and right rear swing links and the front swing link with a relatively simple operation structure that simply connects the lifting mechanism to the rotation support shaft of the rear swing link. it can.
[0018]
The configuration, operation, and effect of the invention according to claim 4 are as follows.
[0019]
〔Constitution〕
In the configuration of the invention according to any one of claims 1 to 3, urging means for applying a rising urging force to the rear swing link is attached to the rotary support shaft.
[0020]
[Action]
When raising the lawn mower, the urging means applies an upward urging force to the left and right rear swing links via the rotation support shaft, and this urging force is used as an auxiliary force for the upward operation and is applied by the elevating operation mechanism. The ascending operation is performed while reducing the ascending operation force.
[0021]
〔effect〕
In raising the lawn mower, the raising operation can be easily performed using the urging force of the urging means as an auxiliary force.
[0022]
The configuration, operation, and effect of the invention according to claim 5 are as follows.
[0023]
〔Constitution〕
In the configuration of the invention according to any one of claims 1 to 4, the distance between a connection point of the front swing link with respect to the vehicle body frame portion and a connection point with respect to the lawn mowing device is set on the pair of left and right front swing links. A length adjuster to be changed is provided.
[0024]
[Action]
Adjusting the length adjusters provided on the left and right front swing links will change the distance between the connection point of each front swing link to the vehicle body frame and the connection point to the lawn mower, and the lawn mower will The connection position of the lawn mowing device with respect to the vehicle body changes by swinging up and down with respect to the vehicle body with the connection point with respect to the rocking link as the rocking center.
The lawn mowing device swings the connection point with respect to the front swing link by providing the rear swing link with a length adjustment unit and adjusting the length adjustment unit to adjust the connection point interval of the rear swing link. It swings up and down with respect to the vehicle body as the center of movement, and the connection posture of the lawn mower to the vehicle body changes, but there are obstacles when operating the length adjustment part such as a rear wheel fender near the rear swing link There are many car body parts that tend to become so that adjustment operations are difficult. On the other hand, in the case of the front swing link, since there are relatively few vehicle body parts in the vicinity thereof, it is possible to adjust the connecting posture of the lawn mower device by operating the length adjusting unit relatively easily and easily.
[0025]
〔effect〕
If there is a problem with the connection position of the lawn mower due to manufacturing or assembly errors of the swing link, or work or storage, or if it is necessary to change the connection position, the front swing link Change the connection position of the lawn mower device to the desired one by changing the connection point interval, so that the lawn mower device moves up and down smoothly so that it does not rattle or twist, or rises to the desired connection posture Can be adjusted. In addition, when performing this adjustment, the length adjustment unit can be quickly and easily operated easily and easily at the front of the vehicle body, which is less susceptible to operational obstacles.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIGS. 1 and 2, the rear portion of the traveling vehicle body 10 is provided with a pair of left and right front wheels 1 and 1 freely swinging at the front end portion and a pair of left and right rear wheels 2 and 2 being driven rearwardly. A driving part having an engine 3 positioned slightly rearward of the axle center of the rear wheel 2 is provided, and is positioned in front of the driving part of the traveling vehicle body 10 and slightly forward of the axle core of the rear wheel 2. A driving section having a driving seat 4 and a driving section floor plate 6 supported on the front end side of the traveling vehicle body 10 is provided, and a lawn mower 20 including a moor deck 21 is connected between the front and rear wheels of the traveling vehicle body 10 by a link type coupling mechanism. 30 is connected so as to be moved up and down, and is configured to transmit rotational power from the transmission device 6 located between the left and right rear wheels 2 and 2 to the lawn mowing device 20 via the rotary shaft 7, A riding lawn mower is constructed.
[0027]
In addition to the mower deck 21, the lawn mowing device 20 includes a plurality of rotary mowing blades 22 arranged in the mower deck 21 in the lateral direction of the vehicle body, and gauge wheels 23 attached to the front and rear sides of the mower deck 21. It is. That is, the lawn mowing apparatus 20 is lowered with respect to the traveling vehicle body 10 by the lowering operation of the link type coupling mechanism 30 to cause the vehicle body to travel. Then, each of the plurality of rotary mowing blades 22 is rotated around the axis of the vehicle body in the vertical direction by the driving force from the engine 3, and the mounting height of the gauge wheel 23 with respect to the mower deck 21 or the travel of the lawn mowing device 20. Lawn mowing is performed at a cutting height determined by the lifting height of the vehicle body 10.
[0028]
As shown in FIG. 2 and the like, the traveling vehicle body 10 includes a pair of left and right vehicle body frame portions 11a and 11a facing front and rear, and a front connection frame portion that connects the front end portions of the left and right vehicle body frame portions 11a and 11a. 11b, a front vehicle body frame 11 having a rear connection frame portion 11c connecting the rear end portions of the pair of left and right vehicle body frame portions 11a, 11a, and the rear connection frame portion of the front vehicle body frame 11. 11c includes a pair of left and right rear main frame portions 12a and 12a facing the front end of the vehicle body connected to the front end side, and a seat support frame portion 12b constructed over the front end portions of the left and right rear main frame portions 12a and 12a. The rear body frame 12 is configured. The left and right vehicle body frame portions 11a of the front vehicle body frame 11 are end portions of grooved sheet metal members that are bent so that both end portions are directed to the front and rear of the vehicle body and the intermediate portion is lateral to the vehicle body as viewed in the vertical direction of the vehicle body. The rear connecting frame portion 11c of the front body frame 11 is formed at an intermediate portion of the bent groove sheet metal material. The left and right rear main frame portions 12a of the rear body frame 12 are made of a plate-shaped sheet metal material arranged so that the lateral width direction is in the vertical direction of the vehicle body and the plate thickness direction is in the lateral width direction of the vehicle body, and the seat support frame portion 12b. Is made by combining grooved or flat sheet metal materials.
[0029]
A front wheel support body 13 that supports the left front wheel 1 in a freely swingable manner is connected to one end side, and a front wheel support body 13 that supports the right front wheel 1 in a freely swingable manner is connected to the other end side. An intermediate portion of a front wheel support frame 14 that supports 1 on one end side and the right front wheel 1 on the other end side is connected to the front connection frame portion 11 b of the front body frame 11. Both the front wheel support 13 toward the left front wheel 1 and the front wheel support 13 toward the right front wheel 1 are displaced in the horizontal direction with respect to the axle core 1a of the front wheel 1 at the boss portion 14a of the front wheel support frame 14. The caster shaft core 13a is connected so as to freely rotate. As a result, the left and right front wheels 1 and 1 are supported on the front end of the traveling vehicle body 10 via the front wheel support 13 and the front wheel support frame 14, and the mounting direction with respect to the front wheel support frame 14 is around the caster shaft core 13a. It is a caster wheel that changes freely.
[0030]
The transmission 6 is provided with a pair of continuously variable transmissions that separately transmit the rotational output of the engine 3 to the left rear wheel 2 and the right rear wheel 2. Both the continuously variable transmission that transmits power to the left rear wheel 2 and the continuously variable transmission that transmits power to the right rear wheel 2 are driven by the hydraulic pump driven by the engine 3 and the pressure oil from the hydraulic pump. It is configured as a hydrostatic continuously variable transmission composed of a hydraulic motor that outputs rotational power to the wheel 2, and the rear wheel 2 can be moved forward or backward by changing the swash plate angle of the hydraulic pump. In addition to driving or stopping the transmission of power by stopping the transmission of the rear wheel, it is possible to steplessly change the transmitted rotational power when driving forward or backward. In other words, the rear wheel 2 can be driven in a stepless manner regardless of whether the rear wheel 2 is driven forward or driven backward.
[0031]
As shown in FIG. 3 and the like, the left travel lever 8a linked to the operation part of the continuously variable transmission of the left rear wheel 2 and the right travel linked to the operation part of the continuously variable transmission of the right rear wheel 2 The lever 8b is provided so as to be distributed between the left side and the right side on the front end side of the driver seat 4 of the driver.
That is, the left traveling wheel 8a is swung in the longitudinal direction of the vehicle body to change the speed of the continuously variable transmission, thereby driving and shifting the left rear wheel 2 forward or backward, or stopping the left rear wheel 2 By swinging the lever 8b in the longitudinal direction of the vehicle body and shifting the continuously variable transmission, the right rear wheel 2 is driven and shifted to the forward side or the reverse side, or stopped. When the left and right rear wheels 2 and 2 are driven at the same speed to the forward side or the reverse side by operating the left traveling lever 8a and the right traveling lever 8b as described above and the gears are shifted, the left and right front wheels 1 and 1 are brought into contact with the ground and the rear wheel 2. Due to the propulsion, the mounting direction is straight forward or straight backward, and the vehicle body moves straight forward or backward and travels at a variable speed. When the left and right rear wheels 2 and 2 are driven at different speeds forward or backward, or when one of the left and right rear wheels 2 and 2 is driven forward and the other is driven backward, the left and right front wheels 1 and 1 are grounded. For propulsion by the rear wheel 2, it rotates around the caster shaft core 13 a so as to be mounted in the lateral direction, and the vehicle body has a speed difference in a direction determined by the speed difference between the left and right rear wheels 2, 2 and the driving direction. Or change the direction with the turning radius determined by the driving direction.
Note that the left and right traveling levers 8a and 8b are arranged so as to open the front of the seat 4 when the driver is seated on the driver seat 4 or away from the driver seat 4, as shown by a two-dot chain line in FIG. 4 is retracted from the front side to the lateral side.
[0032]
As shown in FIG. 2 and the like, the link type coupling mechanism 30 includes a pair of left and right front swing links 31 and 31 that are positioned separately on both lateral outer sides of the front end portion of the front body frame 11 of the traveling vehicle body 10; A pair of left and right rear swing links 32, 32 located separately on both lateral outer sides of the rear end portion of the front body frame 11 are configured.
[0033]
As shown in FIGS. 1, 2, 5, etc., a boss portion 31 a formed by welding a cylindrical body is provided on the base end side of each of the pair of left and right front swing links 31, 31, A connecting portion 31b formed by welding a yoke is provided. A boss portion 31a on the base end side of the left front swing link 31 is cylindrical at the front end portion of the left body frame portion 11a of the pair of left and right body frame portions 11a, 11a of the front body frame 11. Is connected to a boss portion 11d formed by welding the boss portions 31a and 11d so as to be relatively rotatable by a connecting shaft 15 extending in the lateral direction of the vehicle body. The free end side connecting portion 31b of the left front swing link 31 is located on the left side of the pair of left and right front connecting brackets 24, 24 erected on the front end portion on the upper surface side of the mower deck 21 of the lawn mower 20. The front connection bracket 24 is connected to a front connection pin 33 in a lateral direction of the vehicle body through which the connection bracket 24 and the connection portion 31b are inserted so as to be relatively rotatable. A boss portion 31a on the base end side of the right front swing link 31 welds a cylindrical body to a front end portion of the right body frame portion 11a of the pair of left and right body frame portions 11a, 11a of the front body frame 11. The boss portion 11d created in this manner is connected to the boss portion 31a and 11d so as to be relatively rotatable by a connecting shaft 15 which is laterally inserted through the vehicle body. The connecting portion 31 b on the free end side of the right front swing link 31 is connected to the right front connecting bracket 24 of the pair of left and right front connecting brackets 24, 24 of the mower deck 21 of the lawn mower 20. 24 and the connecting portion 31b are connected in a relatively rotatable manner by a front connecting pin 33 in the lateral direction of the vehicle body. The connecting shaft 15 that connects the left front swing link 31 to the left body frame portion 11a and the connecting shaft 15 that connects the right front swing link 31 to the right body frame portion 11a are different. Created on the connecting shaft. A boss portion 32a formed by welding a cylindrical body is provided on the base end side of each of the left and right rear swing links 32, 32, and a connecting portion 32b formed by welding a yoke is provided on each free end side. It is. A boss portion 32a on the base end side of the left rear swing link 32 is cylindrical at the rear end portion of the left body frame portion 11a of the pair of left and right body frame portions 11a, 11a of the front body frame 11. The boss portion 11e created by welding the body and the boss portion 11e created by welding the cylinder to the rear end portion of the right body frame portion 11a are attached so as to be relatively rotatable and below the front end portion of the driver seat 4. The vehicle body frame portion 11a on the left side of the single rotation support shaft 16 that is disposed so as to be located on the left side of the vehicle body frame portion 11a is externally fitted to the end portion of the support shaft that protrudes laterally outside the vehicle body and is integrally rotated by a connecting bolt. And is locked so as to be prevented from coming off. The connecting portion 32b on the free end side of the left rear swing link 32 is a left side of a pair of left and right rear connecting brackets 25, 25 erected at the rear end portion on the upper surface side of the mower deck 21 of the lawn mowing device 20. The rear connecting bracket 25 is connected to the rear connecting bracket 25 and the connecting portion 32b so as to be rotatable relative to each other by a rear connecting pin 34 which is lateral to the vehicle body. A boss portion 32a on the base end side of the right rear swing link 32 is externally fitted to a shaft end portion that protrudes outward from the boss portion 11e of the right body frame portion 11a of the rotating support shaft 16 and a connecting bolt. So as to rotate together and be prevented from coming off. The connecting portion 32 b on the free end side of the right rear swing link 32 is connected to the right rear connecting bracket 25 of the left and right rear connecting brackets 25, 25 of the mower deck 21 of the lawn mower 20. 25 and the connecting portion 32b are connected to each other by a rear connecting pin 34 that faces the vehicle body so as to be relatively rotatable.
[0034]
As a result, the pair of left and right front swing links 31 of the link type connecting mechanism 30 are separately provided on the front end portion of the left body frame portion 11a and the front end portion of the right body frame portion 11a. The connecting shaft 15 is supported so as to be swingable up and down, and the front end side of the mower deck 21 of the lawn mowing device 20 is connected to the front body frame 11 so as to be movable up and down, and a pair of left and right rear swing links. 32 and 32 are supported by a pair of left and right vehicle body frame portions 11 a and 11 a of the traveling vehicle body 10 so as to be swingable up and down via a single rotation support shaft 16. The rear end side of 21 is connected to the front body frame 11 so as to be movable up and down. Therefore, the front body frame 11 of the traveling vehicle body 10, the front swing link 31, the rear swing link 32, and the mower deck 21 of the lawn mower 20 constitute a four-link mechanism.
[0035]
As shown in FIG. 4, a fan-shaped support shaft gear 41 that is connected so as to rotate integrally with a portion located on the inner side of the vehicle body frame 11 a on the right side of the rotation support shaft 16, and the support shaft gear 41. A fan-shaped lever gear 42 meshing with the lever gear 42, and one end side of the lever gear 42 is connected to the lever gear 42 so as to be integrally rotatable. In addition, an elevating operation mechanism 40 for elevating the lawnmower 20 with respect to the traveling vehicle body 10 is configured by an elevating lever 44 positioned on the right side of the driving unit. The operation lever 44 includes a lock pin 45 that is slidably supported in the slimming direction of the operation lever 44, and a plurality of notches 46a with which the lock pin 45 is engaged and disengaged. The elevating operation mechanism 40 is provided with a lock mechanism that fixes the operation lever 44 at a predetermined operation position by a lock member 46 supported by the vehicle body frame portion 11a of the vehicle body frame 11.
[0036]
The free end side of the operation arm 47 whose base end portion is connected to the central portion in the longitudinal direction of the rotating support shaft 16 so as to be integrally rotatable, and the left and right rear main frame portions 12a, 12a of the rear body frame 12. A gas spring 49 is attached over the spring receiver 48 supported by the connecting frame 12c connected over the two. The gas spring 49 has a cylinder tube 49a, one end of which is connected to the spring receiver 48 so as to be relatively rotatable, and one end of the gas spring 49 is slidably fitted into the cylinder tube 49a. And a cylinder rod 49b coupled to the cylinder tube 49a so as to be relatively rotatable, and a gas filled in the cylinder tube 49a. The filled gas projects the cylinder rod 49b from the cylinder tube 49a. The left and right rear swing links 32 and 32 are swung to the side where the lawn mowing device 20 is lifted with respect to the traveling vehicle body 10 by urging and slidingly urging the rotation support shaft 16 by this urging force. Energized. When the lawnmower 20 is lowered with respect to the traveling vehicle body 10, the cylinder rod 49b of the gas spring 49 is slid to the side where it enters the cylinder tube 49a. Thereby, the gas spring 49 enables the lawnmower 20 to be lowered.
[0037]
That is, when the lawn mower 20 is moved up and down with respect to the traveling vehicle body 10, the lock pin 45 is notched in the lock member 46 by pushing the lock release button 45 a protruding from the head of the operation lever 44. The lock mechanism comes out of 46a and enters the slot 46b, and the lock mechanism is unlocked. While operating the lock mechanism in the unlocked state in this way, the operation lever 44 is moved around the axis of the support shaft 43 with respect to the lock member 46 that also serves as a member that rotatably supports the support shaft 43. Swing operation. Then, due to this lever operating force, the lever gear 42 rotates around the axis of the support shaft 43, and the support shaft gear 41 is rotated by the lever gear 42 to rotate the rotating support shaft 16, thereby rotating the left and right rear. The swing links 32 are operated to swing downward or upward with respect to the vehicle body frame portion 11a. Then, since the left and right front swing links 31, 31 are interlocked with the rear swing link 32 via the mower deck 21, the rear swing link 32 swings in the same direction as the rear swing link 32, and the grass The mowing device 20 is raised or lowered with respect to the traveling vehicle body 10. When raising the lawn mower 20, the raising operation is assisted by the raising urging force of the gas spring 49, and the operation force applied to the operation lever 44 can be operated relatively lightly. When the lawnmower 20 reaches a predetermined ascending position or descending position, the pushing operation of the lock release button 45 a is released, and the plurality of the lock members 46 are operated by the operation force of the lock spring 45 b positioned inside the operation lever 44. Any one of the notches 46a is inserted. Then, the lock mechanism enters a lock operation state in which the operation lever 44 is locked so as not to be operated to the lowering side due to the weight of the lawn mowing device 20, and for this lever lock, the lawn mowing device 20 is locked at the lifting height operated. it can.
[0038]
As shown in FIGS. 4 and 5, a length adjuster 35 is provided on the base end side of each of the pair of left and right front swing links 31, 31. The length adjusting portion 35 includes a screw cylinder portion 35 a formed by welding a screw cylinder body to a vehicle body side link portion including the boss portion 31 a of the front swing link 31, and the length of the front swing link 31. The screw shaft portion 35b provided in the lawn mowing side link portion provided with the connecting portion 31b. That is, the length of the front swing link 31 is changed by adjusting the length of the screw shaft portion 35b entering and connecting the screw shaft portion 35a by relatively rotating the screw shaft portion 35b and the screw tube portion 35a. The distance D between the axial center of the connecting shaft 15 as a connecting point of the front swing link 31 with respect to the vehicle body frame portion 11a and the axial center of the front connecting pin 33 as a connecting point with respect to the mower deck 21 of the lawn mower 20. To change. The screw shaft portion 35b is provided with a lock nut 36 for fixing the adjusted length of the front swing link 31 so as not to change due to vibration or the like.
[0039]
That is, by operating the length adjusting portions 35 of the left and right front swing links 31 and 31 to change the connection point interval D, the mower deck 21 sets the connection point with respect to the rear swing link 32 as the swing center. The lawn mowing device 20 can be adjusted in the connecting posture with respect to the vehicle body.
[0040]
As shown in FIG. 4, the pair of left and right front connection brackets 24, 24 and the pair of left and right rear connection brackets 25, 25 provided in the mower deck 21 of the lawn mower 20 are provided with long connecting holes 24a, 25a, respectively. is there. Each of the connecting long holes 24a and 25a allows the connecting pins 33 and 34 to be slidably inserted, and the lawn mowing device 20 connects the front swing link 31 and the rear swing link 32 with the connection long holes 24a. The mower deck 21 is connected to the front swing link 31 and the rear swing link 32 while allowing the vehicle to move up and down in the vertical direction within a stroke range determined by the length of 25a.
[0041]
As a result, the front wheel 1 and the rear wheel 2 enter the recessed portion of the ground, or the obstacle climbing roller 26 provided on the front end side of the gauge wheel 23 or mower deck 21 of the lawn mower 20 rides on the raised portion or the like. Even if a pushing force is applied to the lawn mowing device 20, the lawn mowing device 20 is connected to the front swing link 31 and the rear swing link 32 because of the connection long holes 24 a and 25 a of the front connection bracket 24 and the rear connection bracket 25. On the other hand, it is possible to work while reducing the impact force applied to the lawn mowing device 20 from the ground side.
[0042]
[Another embodiment]
Instead of providing the long connecting holes 24a and 25a on the front connecting bracket 24 and the rear connecting bracket 25, the connecting pins 33 and 34 slide toward the connecting portion 31b of the front swing link 31 and the rear swing link 32. You may implement by providing the long hole for a connection which penetrates freely. Also in this case, when an operating force is applied to the lawn mowing device 20 from the ground side, the lawn mowing device 20 rises with respect to the front swing link 31 and the rear swing link 32, and the impact force applied to the lawn mowing device 20 is reduced. Work while relaxing.
[0043]
In place of the gas spring 49, a coil spring or a combination of a coil spring and a gas spring is used, and the rear swing link 32 is configured to swing and urge toward the ascending side of the lawn mowing device 20. These gas springs 49, coil springs and the like are collectively referred to as urging means 49.
[Brief description of the drawings]
FIG. 1 is a side view of the entire riding lawn mower.
FIG. 2 is a plan view of the vehicle body and a coupling mechanism.
FIG. 3 is a front view of a driving unit.
FIG. 4 is a side view of a coupling mechanism and a lifting operation mechanism.
FIG. 5 is a plan view of the left side portion of the coupling mechanism.
FIG. 6 is a side view of the entire conventional riding lawn mower.
[Explanation of symbols]
1 front wheel
2 Rear wheels
4 Driver's seat
10 Traveling body
11a Body frame
16 Rotating spindle
20 Lawn mower
24a, 25a long hole for connection
35 Length adjuster
40 Lifting mechanism
49 Energizing means

Claims

A lawnmower (20) is connected between the front and rear wheels of a traveling vehicle body (10) comprising a pair of left and right free-wheeling front wheels (1) and a rear wheel (2) that can be driven, and a driving seat (4). A riding lawn mower
A pair of left and right front swing links (31) that are supported by one and the other of the pair of left and right body frame portions (11a) of the traveling vehicle body (10) so as to freely swing up and down, and the pair of left and right body frame portions. A pair of left and right rear swing links (32) supported so as to rotate integrally with a single rotation support shaft (16) that is horizontally movable and is disposed across one and the other of (11a). And the pair of left and right front swing links (31) and the pair of left and right rear swing links (32), respectively, with the position between the vertical widths of the pair of left and right body frame portions (11a) as the swing axis. A pair of left and right vehicle body frame portions (11a) are disposed laterally laterally outside, and the front end side of the lawn mower (20) is placed on the free end side of the pair of left and right front swing links (31). The lawn mower on the free end side of the rear swing link (32) (20) a rear end respectively connected relatively rotatably in the coupled to a rotary shaft (16) a pair of left and right rear swing links (32) of the tilting operation by an elevating operation mechanism (40) By doing so, the pair of left and right front swing links (31) is swung together with the rear swing link (32) so that the lawnmower (20) is moved up and down with respect to the traveling vehicle body (10). A riding lawn mower.

One of the pair of left and right front swing links (31) and rear swing links (32) and the lawn mowing device (20) includes a lawn mowing device (20) and a swing link (31) (32). In addition, there are provided connecting long holes (24a) (25a) for connecting the swing links (31) (32) and the lawnmower (20) in a state in which they are allowed to move in the vertical direction of the vehicle body. Item 1. A riding lawn mower according to item 1.

Together with the coupling the elevating operation mechanism to the rotary shaft (16) (40), with the elevation operating mechanism (40) by rotating the support shaft (16) rotational operation to right and left pair of rear swing links (32) The riding lawn mower according to claim 1 or 2, wherein the lawn mower (20) is moved up and down relative to the traveling vehicle body (10) by swinging the pair of left and right front swing links (31). .

The riding lawn mower according to any one of claims 1 to 3, wherein an urging means (49) for applying an upward urging force to the rear swing link (32) is attached to the rotary support shaft (16).

A length for changing the distance between the connection point of the front swing link (31) to the vehicle body frame portion (11a) and the connection point to the lawn mowing device (20) between the pair of left and right front swing links (31). The riding lawn mower according to any one of claims 1 to 4, further comprising an adjustment unit (35).