| 摘要 |
<p>PROBLEM TO BE SOLVED: To simplify the structure by providing a bush which is inserted to be fitted in a sleeve under pressure, thereby forming a predetermined gap between an inner wall surface and a cylindrical lower portion of a supporting shaft. SOLUTION: As a bush 130 is inserted to be fitted in a lower portion 111b of a sleeve 111 under pressure until a tilted surface 130a of the bush contacts a lower surface of a spherical center portion 121b, a pinch roller is rotatably mounted. The contact at these two positions enables the pinch roller 110 to turn within a range substantially determined by the size of a gap between a cylindrical upper portion 121a of a supporting shaft 121 and an upper portion 111a of the sleeve 111, and the size of a gap between the cylindrical portion 121a of the supporting shaft 121 and an inner wall surface 130b of the bush 130.</p> |
