Henry Quackenbush
Henry Marcus Quackenbush , commonly called H.M., was an American inventor and industrialist who founded the H.M. Quackenbush Company in Herkimer, New York. His company was widely known for its air rifles and for the invention of the metal, springjointed nutcracker.
Quackenbush was born in Herkimer, New York, in 1847. At age fourteen, he began an apprenticeship at gun manufacturer Remington Arms Co., where he acquired skills as a metalworker and gunmaker. At the age of 16, he invented the extension ladder, which he patented on Oct. 22, 1867, and then began manufacturing them himself, until he sold the patent for 500. Several years later, he left his job at Remington to start his own metal working and gun shop in his hometown of Herkimer.
Source: Wikipedia