| 摘要 |
PURPOSE:To safely and surely exert the packing effect by forming a check metal in a three-piece structure, inclining a movable plate arranged in the middle, and holding the contact with a shield main body and the inner periphery of a cover segment. CONSTITUTION:Check metals 12 arranged at an interval over the whole periphery on the back of an entrance rubber 7 are formed into a three-piece structure, a connecting elastic plate 13 is provided on the entrance rubber 7 side, a stopping plate 14 is provided on the opposite side. An outside fixed plate 15 and an inside movable plate 16 connected to it are pinched between both 13 and 14. The outside fixed plate 15 is pinched and fixed between the elastic plate 13 and the stopping plate 14, the inside movable plate 16 is fixed only to the elastic plate 13. The inside movable plate 16 is kept in the inclined state as a shield main body and a covered segment are moved forward, the contact with the outer periphery is invariably held regardless of the difference of their outer diameters. |
