We don’t know the name of the actual inventor of ripstop, but we can safely say that ripstop fabrics made their first real appearance in the early 1940s. It wasn’t until 1 May 1962 that an initial ripstop patent was filed with the U.S. government (the patent-seekers were inventors Louis Weiner and Harold H. Brandt who titled their filing “Parachute Fabric Containing Stretch and Non-Stretch Type Ripstops”).
Image source: Google Patents