patent dispute

I wrote a technique and a Amrican businessman applied three patents based on my materials, we are co-inventor. Then he set up a comapny try to use these techniques, asked me to transfer these patents to the company (actually to him) by One dollar each, I centainly refused to doing so. Recently the patent agent (attorney) sent me documents to sign, try to remove my name from the patents. the Businessman paid the application fee. they said if I didn't sign, they have other mehtods to remove my name. the businessman knows nothing about the techniques.
Oversea Chinese people, be careful such American businessman!!
any advices imput are appreciated.