PROBLEM TO BE SOLVED: To provide a combine responding to the recently increasing demand of cost reduction by simplifying a structure for the reduction of a tertiary loss as much as possible.SOLUTION: The combine is provided by constituting a linking means 390 linking an actuator 391 with an opening/closing mechanism 264 for a chaff sieve 261 by a rotary member 394 rotating forward and backward by the drive of the actuator 291 and a pair of rotation-detecting members 400, 401 capable of making a contact with a cam part 396 formed at the outer peripheral side of the rotary member 394. By the command of a control means 310, the rotary member 394 is kept waiting while one of the rotation-detecting means 400 is ON state, and on detecting that there is no straw to be discharged by a discharging straw-detecting means 317, the rotary member 394 is rotated forward until the other rotary-detecting member 401 becomes ON state to forcefully open the chaff sieve 261 through the opening/closing mechanism 264. After the lapse of a predetermined time, the forceful opening is released by rotating the rotary member 394 backward until one side rotation-detecting member 400 becomes ON state.COPYRIGHT: (C)2011,JPO&INPIT【課題】コンバインにおいて、3番ロス低減のための構造をできるだけ簡素化し、近年高まっているコストダウンの要請に応える。【解決手段】チャフシーブ261用の開閉機構264にアクチュエータ391を関連付ける連係手段390を、アクチュエータ291の駆動にて正逆回動する回動部材394と、回動部材394の外周側に形成されたカム部396に当接可能な一対の回動検出部材400,401とで構成する。制御手段310の指令にて、一方の回動検出部材400が入りの状態で回動部材394を待機させ、排藁検出手段317が排藁なしを検出すれば、他方の回動検出部材401が入りの状態になるまで回動部材394を正回動させて、開閉機構264を介してチャフシーブ261を強制開放させ、所定時間経過後に、一方の回動検出部材400が入りの状態になるまで回動部材394を逆回動させて強制開放を解除する。【選択図】図6
