| 摘要 |
An umbrella includes a plurality of top ribs pivotally secured to a notch formed on an upper end of a central shaft and a plurality of stretcher ribs each pivotally secured between each top rib and a runner slidably held on the central shaft, each top rib being embedded with a reinforcing core rod for strengthening the top rib in order to resist an external force acting upon an umbrella cloth secured on the top ribs.
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