PROBLEM TO BE SOLVED: To provide a coupling device for preventing damage of a locking mechanism part for locking a hook member when a tilling implement is mounted on a tractor.SOLUTION: The coupling device 40 includes hook members 55, that are arranged rotatably in the vertical direction on sides of engagement plates 49 fixedly set up at both sides in the width direction of a connection frame 41 connected to a three-point link connection mechanism 91 arranged at the rear of a tractor 90 and capable of engaging with hitch pins 26. A lock mechanism part 60 is provided to lock the hook members 55 at positions for engaging with and releasing the hitch pins 26. Rotation fulcrums O of the hook members 55 are arranged on extensions in the action directions of external force in which the hitch pins 26 are contacted with the tip parts of the hook members 55 in locked states of the hook members 55 at engaged positions, and contact surfaces which pass through contact points in which external force is in contact with the tip parts of the hook members 55 and are perpendicular to the direction of external force are arranged on the tip parts of the hook members 55.COPYRIGHT: (C)2011,JPO&INPIT【課題】耕耘作業機をトラクタに装着する際に、フック部材をロック可能なロック機構部の損傷を防止可能な連結装置を提供する。【解決手段】連結装置40は、トラクタ90後部に設けられた三点リンク連結機構91に連結される連結枠41の幅方向両側に配設された係合プレート49の側面に上下方向に回動自在に設けられてヒッチピン26を係止可能なフック部材55がヒッチピン26を係止及び係止解除する位置にフック部材55をロック可能なロック機構部60を備え、フック部材55の回動支点Oを、フック部材55が係止位置にロックされた状態で、ヒッチピン26がフック部材55の先端部に当接する外力の作用方向延長線上に設け、フック部材55の先端部に、外力がフック部材55の先端部に接する接点を通って外力の方向に直交する当接面を設ける。【選択図】 図1
