[Avodah] Shabbos Umbrella

[Micha Berger]

RGS's daily vort today posted a link to an article by Eretz Chemdah which
described a design for an umbrella that could be opened on Shabbos. The
design change is simple: There is a "Magein haShabbas" on the umbrella's
shaft above the main dome that is a tefach wide and cannot close. So
that opening the umbrella is enlarging an ohel arai, not creating one.

See https://www.torahmusings.com/wp-content/uploads/2021/10/13808-%D7%9E%D7%98%D7%A8%D7%99%D7%94-%D7%9E%D7%92%D7%9F-%D7%94%D7%A9%D7%91%D7%AA.pdf
or https://bit.ly/3BX3ytF

Here's my question: Don't people put umbrellas down? So, this magein is
often less than a tefach off the floor, or sideways while the umbrella
is being put down and the top is rotated to the bottom.

Wouldn't you have to also keep the umbrella upright?

Tir'u baTov!
-Micha

-- 
Micha Berger                 Here is the test to find whether your mission
http://www.aishdas.org/asp   on Earth is finished:
Author: Widen Your Tent      if you're alive, it isn't.
- https://amzn.to/2JRxnDF                      - Richard Bach