My grandmother had one too. I just barely remember sneaking under it one time before she had a chance to pull it up to the ceiling. (I was in awe over the fact that she had it hanging from her ceiling.
I'll ask my mother if she remembers how it was set up. She is almost 91 so she may not remember all of the details.
Edited to add: I just did a google search and found this website....
http://www.ehow.com/how_4842623_anti...ing-frame.html