PROBLEM TO BE SOLVED: To provide a mechanical linkage unit capable of performing draft control and automatic tillage depth control.SOLUTION: A tractor includes: a hydraulic lifting/lowering drive unit 17 and a mechanical linkage unit 18 converting a change amount of traction load or change amount of tillage depth into a lifting/lowering operation amount to be transmitted to the lifting/lowering drive unit 17. A change amount conversion mechanism 33 of the mechanical linkage unit 18 can be switched between a first conversion state and second conversion state and includes: a load detection member 36 oscillating according to traction load and an oscillation member 38 oscillating according to tillage depth. When the change amount conversion mechanism 33 is switched into the first conversion state, the change amount conversion mechanism 33 can convert a change amount of traction load obtained by forward/rearward oscillation of the load detection member 36 into a lifting/lowering operation amount. When the change amount conversion mechanism 33 is switched into the second conversion state, the change amount conversion mechanism 33 can convert a change amount of tillage depth obtained by oscillation of the oscillation member 38 into a lifting/lowering operation amount.SELECTED DRAWING: Figure 3COPYRIGHT: (C)2018,JPO&INPIT【課題】ドラフト制御と自動耕深制御とを行える機械式連係ユニットを提供する。【解決手段】トラクタは、油圧式の昇降駆動ユニット17と、牽引負荷の変化量又は耕深の変化量を昇降操作量に変換して昇降駆動ユニット17に伝える自動昇降用の機械式連係ユニット18とを備え、機械式連係ユニット18の変化量変換機構33は、第1変換状態と第2変換状態とに切り替え可能で、牽引負荷に応じて揺動する負荷検出部材36と、耕深に応じて揺動する揺動部材38とを備え、変化量変換機構33が第1変換状態に切り替えられると、変化量変換機構33は、負荷検出部材36の前後揺動で得られる牽引負荷の変化量を昇降操作量に変換可能であり、変化量変換機構33が第2変換状態に切り替えられると、変化量変換機構33は、揺動部材38の揺動で得られる耕深の変化量を昇降操作量に変換可能である。【選択図】図3
