I've had cheap-o umbrellas with folding ribs that fold and then never expand again. I've also had a straight-ribbed umbrella that flipped inside out in a strong wind.

I propose an umbrella with ribs in the shape of two opposing fibonacci spirals, like the pattern you see in pineapple scales or sunflower seed heads.

So each rib would be supported at several points by contravening ribs, and the umbrella would resist turning inside out in a strong wind. Each rib would be more break resistant.

The whole spiral lattice would simply collapse down around the central pole like regular straight-ribbed umbrellas.

Also the fibonacci spiral looks really cool.
-- lawpoop, Jul 17 2003

Fibonacci spirals in flowers. http://www.pims.mat...00/bus00/sunflower/
good examples of the spiral pattern I'm talking about. [lawpoop, Oct 04 2004]

I understand the spiraling support structure but can't visulaize how it would be constructed so that it could collapse in an orderly, or compact, way.
-- bristolz, Jul 17 2003


I had the same problem. But simply strenthening the ribs goes a long way toward fixing your problems; the other solution which works well is providing air vents.
-- DrCurry, Jul 17 2003


For collapsing to work properly, the ribs would have to slide over each other, and touch at different points when folded than they do when expanded.

I imagine that the ribs of the top spiral are connected to the fabric, and each rib of the bottom spiral has a groove that a connector to the top spiral slides along.

So , as you expand or collapse the umbrella, the two spirals twist around each other, with their connectors sliding in channels on the bottom spiral.
-- lawpoop, Jul 17 2003


G++d
-- thumbwax, Jul 17 2003


This deserves to stay aloft a while longer.
-- egbert, Jul 18 2003



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