Multiple-fold windproof umbrella for preventing sagging of umbrella cloth

A multiple-fold windproof umbrella comprising:

• a central shaft;
• a rib assembly having at least a top rib pivotally secured to an upper notch formed on a top portion of the central shaft, a stretcher rib pivotably connected between a lower runner slideably held on the central shaft and an outer rib;
• with said stretcher rib pivotally connected with said top rib;
• a lower cloth secured on the rib assembly and having an upper peripheral portion of said lower cloth connected with an anti-sagging band which is fastened on the rib assembly;
• a central opening defined between said anti-sagging band and said upper notch of said central shaft;
• said anti-sagging band having elasticity to be stably held on said rib assembly without sagging of said upper peripheral portion of said lower cloth from said rib assembly;
• an upper cloth secured to the upper notch of the central shaft and juxtapositioned above said lower cloth and said anti-sagging band;
• and
• a plurality of control valves each control valve formed between the upper cloth and said rib assembly, having an annular opening defined between said upper cloth and said lower cloth, said annular opening communicated with said central opening in said anti-sagging band;
• said control valve normally resiliently restoring said upper cloth to approximate said lower cloth to close said annular opening defined between said upper cloth and said lower cloth;
• whereby upon blowing of a strong wind, each said control valve will be opened to open the annular opening between the upper and lower cloths to escape the wind;
• and upon escape of the wind, each said control valve will automatically restore to close said upper cloth on said lower cloth for closing the annular opening between said upper and lower cloths.