| 摘要 |
PROBLEM TO BE SOLVED: To prevent the free rotation of respective pipes constituting a multistage type freely extendible and contractible shaft for which a slide guide is not made to appear and to smoothly extend and contract the shaft. SOLUTION: The plurality of pipes 4, 6 and 8 are fitted and inserted slidably in a nesting shape. At the inner diameter parts of the respective pipes 4 and 6 excluding the pipe 8 on the innermost side of the shaft among the plurality of pipes, recessed grooves 10 and 12 are formed over the entire length in a longitudinal direction. At the outer diameter parts of the rear end parts of the respective pipes 6 and 8 excluding the pipe 4 on the outermost side of the shaft among the plurality of pipes, projecting lines 14 and 16 are formed. The projecting lines 14 and 16 are fitted freely slidably in an axial direction to the recessed grooves 10 and 12 at the inner diameter parts of the pipes on the outer side, and the relative rotation of the pipes on the outer side and on the inner side is blocked. COPYRIGHT: (C)2005,JPO&NCIPI
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