| 摘要 |
An automatic umbrella includes a retraction restoring spring having an outer spring end contracted to form a narrow spring portion to be embedded in a concavely depressed stretcher rib and having an inner spring end secured to a top rib of a rib assembly for holding an umbrella cloth for smoothly developing the restoring spring force, and an extending spring formed in the central tubular shaft having an upper spring portion having larger spring diameter to be telescopically held in an upper shaft having larger diameter and a lower spring portion having smaller spring diameter than the upper spring portion to be telecopically held in a lower shaft, thereby causing a smooth tensioning or compression of the extending spring in the upper shaft and the lower shaft when extending or retracting the central tubular shaft.
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