When were doorknobs invented?

It isn\'t easy to prove the exact year when doorknobs were used. The first documentation of the invention of the knob was in 1878. The U.S. patent office received the submission made from improvements on the door closing device. It was invented by African American male named Osborn Dorsey. However, much before the knobs and handles were used commercially, the doors came with a bolt. It kept the door shut. Most people used a leather thong or string to loop around the wooden bar.