| 摘要 |
PROBLEM TO BE SOLVED: To surely rewind a screen around a winding member even when environmental temperature is decreased. SOLUTION: When the environmental temperature is decreased, a cover member 30 is contracted in a radial direction. Moreover, when the screen 12 is developed from the winding member 26, expansion in the radial direction of a part in a longitudinal direction in a coil spring 28 is restricted by a cover section 30A out of a plurality of cover sections 30A, 30B, 30C provided in the cover member 30. Therefore, when the screen 12 is developed from the winding member 26 from this condition, the remaining part in the longitudinal direction of the coil spring 28 is equivalent to the effective length of the coil spring 28, and the effective length of the coil spring 28 is shortened compared to that before a decrease in the environmental temperature. Thus, the torsional force of the coil spring 28 is increased compared to that before the decrease in the environmental temperature (ordinary temperature), and the screen 12 can be rewound around the winding member 26 surely. COPYRIGHT: (C)2009,JPO&INPIT
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