Fred Bacon patented the “Soft Pedal Banjo Mute” May 31, 1928. Though it’s rarely used by any musician, and only once known in recording (Massa’s In The Cold, Cold Ground), By Stephen Foster, it was put on most banjos Bacon produced from 1928 until 1940.
Here he is showing off his new patent. But more important is the contribution Bacon & Day Banjos made upon the world.