| 摘要 |
An umbrella having a central shaft, a spindle slidably disposed on the shaft and moveably between an upper opening position and a lower closed position, a plurality of first and second radially extending ribs hingedly secured between the shaft t and spindle, an umbrella canopy being supported on the first ribs, the canopy having upper and lower canopy portions, the lower canopy portion having central first and third annular air intransmissible portions disposed at an upper end of the shaft and an outer end of the first radially extending ribs, a second central air transmissible portion disposed between the first and third central air intransmissible portions, the upper canopy portion having an air transmissible material and disposed over the first of the intransmissible. portion around an upper end of the shaft and the second air transmissible portion, and overlapping in part onto the third annular air intransmissible portion, the upper and lower canopy portions being placed under tension and being taut between the pairs of second plurality of extending ribs when the spindle is in a open position such that air impinging on the lower surface of the upper canopy portion being vented through the air transmissible material of the lower canopy portion and then along a channel formed between the upper and lower canopy portions.
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