Status: concept on sale, search for manufacturers!
A Sack-bag. The bag is made out of a single thin durable cloth with eyelet holes for tension regulation; it is also supported by a metal carcass-frame. The metal carcass is made out of a rod with one joint which is hidden inside the handle. Owing to this the bag becomes a self-closing spring with good load bearing capacity.
A string bag is one of the genius inventions of humanity. But if to the existing prototype you add a shoulder-strap and make it out of the modern fosta nylon polyvinylchloride reinforced plastic thread, you’ll get an irreplaceable in everyday life, more than reliable, compact and comfortable bag for carrying heavy objects.