PROBLEM TO BE SOLVED: To provide a ground work implement-supporting device which can assist the rotation of a holder at a proper speed and with a proper biasing force, when the ground work implement is mounted, and can control a rotation speed biased with the first biasing tool with the second biasing tool to reduce the rotation speed to the upper side of a holder when the ground work implement is dismounted.SOLUTION: A holder 5 for upward or downward rotatably mounting the ground work implement 4 is supported by the rear support frame 2 of a working machine K. The first biasing tool 7 and the second biasing tool 8 for rotating the holder 5 in an identical biasing direction are disposed on a rotation assist mechanism 6 for biasing the holder 5 in a direction for rotating the upper side to reduce the lifting force of the ground work implement 4. A speed for rotating the holder 5 due to the biasing of the second biasing tool 8 is lower than that by the first biasing tool 7.COPYRIGHT: (C)2011,JPO&INPIT【課題】対地作業具の装着時には適正な速度及び付勢力でホルダの回動をアシストしながら、対地作業具を外した状態では、第1付勢具の付勢による回動速度を第2付勢具が抑え、ホルダの上方への回動速度を遅くすることができる。【解決手段】作業機K後部の支持フレーム2に上下回動可能に対地作業具4を装着するホルダ5を支持し、このホルダ5を上方側に回動させる方向に付勢して対地作業具4の持ち上げ力を軽減する回動アシスト機構6に、ホルダ5を回動させる付勢方向が同一である第1付勢具7と第2付勢具8とを設け、この第2付勢具8の付勢によるホルダ5を回動させる速度が第1付勢具7より遅くしている。【選択図】図1
