PROBLEM TO BE SOLVED: To prevent formation of tillage mark, while keeping ground leveling function depending on a rear cover.SOLUTION: A tillage part 15 is set at the lower part of a machine frame F, an upper cover 17 covering the upper side of the tillage part 15 is set at the machine frame F, and on the rear-end side of an upper part 17, a rear cover 18 is supported vertically swingingly, a spring push-down device 40 for impelling the rear cover 18 downward, with a spring element 53 and a resisting means 43, giving resistance against at least downward movement of vertical movement of the rear cover 18 are provided.COPYRIGHT: (C)2009,JPO&INPIT【課題】後部カバーによる整地性を確保しつつ耕耘跡ができることを防止する。【解決手段】機枠Fの下部側に耕耘部15が設けられると共に、当該機枠Fに耕耘部15の上方側を覆う上部カバー17が設けられ、この上部カバー17の後端側に上下揺動自在に支持された後部カバー18が設設けられ、バネ部材53により後部カバー18を下方に付勢する弾下装置40が設けられ、後部カバー18の上下動のうち少なくとも下動に対して抵抗を与える抵抗手段43が設けられている。【選択図】図2
