| 摘要 |
Small-diameter sections are provided at the opposite ends, in the axial direction (front-rear direction), of the inner peripheral surface of a fitting/holding portion which is a portion having an inner diameter which is increased and decreased as an adjustment lever is operated, and a large-diameter section having a greater inner diameter than the small-diameter sections is provided at the axially intermediate section of the inner peripheral surface. Reducing the diameter of the fitting/holding portion by operating the adjustment lever causes the outer peripheral surface of the rear end of an inner column and the small-diameter sections to make contact with each other. |
