Patent attributes
A folding shaft for umbrellas includes a first section having a circular cross section and the first section is retractably received in a second section which includes an enclosed cross section which includes a plurality of straight sides and a plurality of first curved portions connected between the straight sides. A third section is movably mounted to the second section and including an enclosed cross section which includes a plurality of inward curved sides and a plurality of second curved portions connected between the inward curved sides. The inward curved sides of the third section are located corresponding to the straight sides of the second section. The second curved portions of the third section are located corresponding to the first curved portions. The gap between these sections can be controlled to be the minimum.
