Tried to find plans - looks like this guy is looking for investors to do these as a business. So, doubt you will get his drawings. Doesnt look too difficult, but a few of the dimensions would be somewhat critical. The piece going back from the foot bar connects to another that slides up and down under the seat. Looks like it 'locks' the leg in place, but then pops right back when they push it. If you can figure the details of that out...