PROBLEM TO BE SOLVED: To provide a compact multistage expansion device which reduces a difference in external dimension between stages, increases design flexibility of a device cylindrical body, increases stiffness of the device, and improves assemblability and maintainability of components in the device.SOLUTION: The multistage expansion device comprises an outermost stage cylindrical body, an intermediate stage cylindrical body, and an innermost cylindrical body. The cylindrical bodies can be protruded successively from the inside of the outermost stage cylindrical body. In the multistage expansion device, a pulley around which a wire for pulling the intermediate cylindrical body is wound and which is movable integrally with the intermediate cylindrical body is disposed in the innermost stage cylindrical body.COPYRIGHT: (C)2012,JPO&INPIT【課題】多段伸縮装置において、各段の外形寸法差を小さくして装置の小型化・装置筒状体の意匠自由度の向上・装置の剛性を向上、さらには装置内部にある部品の組立保守性を改善した多段伸縮装置を提供すること。【解決手段】最外段筒状体、中間段筒状体、最内段筒状体とからなり、最外段筒状体内から順次次段の筒状体が出没可能になされた多段伸縮装置において、中間段筒状体を牽引するワイヤが巻回され、前記中間段筒状体と一体として移動可能になされたプーリが、最内段筒状体内部に配設されるようにした。【選択図】図2
