| 摘要 |
PROBLEM TO BE SOLVED: To provide a sufficient telescopic holding force even after extremely long elapsed time from an initial state. SOLUTION: The top of a bead 4c of a clamp part 4a of an outer column 4 is formed in a shape in which the top contacts through a surface (surface abutting) with an outer peripheral surface of an inner column 3 with a circumferential predetermined width spaced, so that the top of the bead 4c abuts on the inner column 3 through a surface to reduce bearing pressure to the inner column 3. As a result, the inner column 3 hardly plastically deforms, and the sufficient holding force can be provided even when an operation angle of an operating lever is similar to an initial angle. In addition, the bearing pressure of the top of the bead 4c to the inner column 3 can be reduced, so that the top of the bead 4c hardly wears to provide the sufficient holding force even after telescopic sliding of both columns 3 and 4 are repeated. |
