PROBLEM TO BE SOLVED: To prevent a ground leveling device or a lifting link mechanism from being broken when the ground leveling device is subjected to overload in a rising direction.SOLUTION: In a riding rice transplanter 1 wherein a ground leveling device 6 for performing a ground leveling operation between a traveling machine body 3 and a planting machine 5 is connected to the front part of the planting machine 5 via a lifting link mechanism 30 and wherein the height of the ground leveling device 6 is adjustable according to the operation of an operating lever 21, the lifting link mechanism 30 includes a swing arm 32 which hangs the ground leveling device 6 via a rod 33 and which swings up and down according to the operation of the operating lever 21. The rod 33 is connected to the swing arm 32 in such a manner as to freely move in and out vertically. The rod 33 is biased downward by the biasing force of a spring 40. When the ground leveling device 6 is subjected to overload in a rising direction, the rod 33 is retreated upward against the biasing force of the spring 40.COPYRIGHT: (C)2014,JPO&INPIT【課題】整地装置が上昇方向の過負荷を受けたとき、整地装置や昇降リンク機構の破損を防止する。【解決手段】走行機体3と植付作業機5との間で整地作業を行なう整地装置6を、植付作業機5の前部に昇降リンク機構30を介して連結するとともに、操作レバー21の操作に応じて整地装置6の高さを調節可能な乗用田植機1において、昇降リンク機構30は、ロッド33を介して整地装置6を吊持し、かつ、操作レバー21の操作に応じて上下に揺動する揺動アーム32を備え、該揺動アーム32に対してロッド33を上下方向に進退自在に連結するとともに、スプリング40の付勢力でロッド33を下方に付勢し、整地装置6が上昇方向の過負荷を受けたときは、スプリング40の付勢力に抗してロッド33を上方に退避させる。【選択図】図4
