The transmission mechanism includes a tow pushing member having a distal end portion connected to the elevator base and a base end portion connected to the elevating operation portion, a storage portion for storing the tow pushing member by projecting the distal end portion of the tow pushing member . The transmission mechanism further includes a telescopic member into which the distal end side of the tow pushing member protruding from the accommodating portion is inserted.伝達機構は、起上台に連結される先端部と起上操作部に連結される基端部とを有する牽引押圧部材と、牽引押圧部材の先端部を突出させて牽引押圧部材を収納する収納部とを有する。伝達機構は、収納部から突出される牽引押圧部材の先端部側が挿入される伸縮部材をさらに有する。
