PROBLEM TO BE SOLVED: To facilitate maintenance work by forming a wide maintenance space by rotating a plurality of raising devices upward.SOLUTION: An intermediate raising frame (58) integrated with a center raising device (61) is rotatably supported by a rotating shaft (49) on an upper part of an intermediate upper raising transmission shaft (45b). A second upper side gear (43a) provided on the intermediate upper raising transmission shaft (45b) and a second lower side gear (50a) on an intermediate raising input transmission shaft (53) provided on the intermediate raising frame (58) are arranged to face each other. As power is transmitted to transmit power to the center raising device (61), and when the intermediate raising frame (58) is rotated downward around the rotating shaft (49), the second upper side gear (43a) and the second lower side gear (50a) are engaged to make a power transmission state. As an upper raising transmission cylinder member (46) is rotated upward, engagement of the second upper side gear (43a) and the second lower side gear (50a) is released to make a non-power transmission state.COPYRIGHT: (C)2012,JPO&INPIT【課題】複数の引起装置を上方へ回動させて広いメンテナンス空間を形成し、メンテナンス作業を容易にする。【解決手段】中央の引起装置(61)と一体の中間引起フレーム(58)を中間上部引起伝動軸(45b)上部の回動軸(49)で回動自在に支持し、中間上部引起伝動軸(45b)に設けた第2上手側ギア(43a)と中間引起フレーム(58)に設けた中間引起入力伝動軸(53)の第2下手側ギア(50a)とを対向配置して動力を伝達して中央の引起装置(61)に動力を伝達し、回動軸(49)回りに中間引起フレーム(58)を下方に回動すると、第2上手側ギア(43a)と第2下手側ギア(50a)が噛み合って動力伝達状態になり、上部引起伝動筒体(46)を上方に回動すると、第2上手側ギア(43a)と前記第2下手側ギア(50a)との噛合いが離脱して非動力伝達状態となる構成とした。【選択図】図11
