" a state before the band is mounted; [0195]FIG. 208 is a sectional view taken along the line A-A of FIG. 206, showing a state in which the band has been mounted; [0196]FIG. 209 and FIG. 210 each show a twenty-seventh embodiment of the present invention, and are a plan view and a side view of an operating section which can be applied to the sixteenth or twenty-first embodiment; [0197]FIG. 211 is a" . . . .