This is a project that I assisted a former university colleague on at the end of last year and he has just sent over some photos of the final result.
Phil wanted to convert a standard road bike frame into a folding bike and designed some very simple and elegant hinges and break points. After a few discussions and refinements to the design, we ended up with the mechanical joints that you see below.
The two hinges fit on the top tube and lock in place. One of these hinges has an element of rotation in order to allow the bike to fold out of alignment to prevent the wheels folding into each other.
This is the breaking point. Both pieces lock together then the outer knurled stainless steel sleeve screws them both together. (There was some clever machining to get everything to fit perfectly and the threads to align perfectly on this).
Hello, is so awsome, where you buy the coupler??