Off-center umbrella patent was filed in US in 1995. http://www.google.com/patents/US5505221
The same product already in the Japanese market several years ago.
A Chinese folk copied the idea and shamelessly claimed the idea is original in a CCTV program. He got RMB 18 million investment fund from two investment companies through copycat.
http://tv.cntv.cn/video/C24907/207bceadbe264a869be197423580a3ee