Linus Yale Jr. (1821-1868) was an American mechanical engineer and manufacturer who developed the cylinder pin-tumbler lock (and other key and combination locks). Yale’s father, Linus Yale, had invented an earlier pin-tumbler lock in 1848; the son’s lock used a smaller, flat key with serrated edges (like the ones we still use today).
Yale patented his cylinder pin-tumbler lock in 1861. This very secure lock is still widely in use today in car doors and the outside doors of buildings. The cylinder pin-tumbler lock consists of (usually 5) pairs of bottom pins and top drivers, held in position by springs. When the right key is put into the lock, the bottom pins are pushed to the right position, allowing the key to turn and the lock to unlock. Yale introduced a combination lock a year later.
Yale opened his first lock shop in the 1840’s in Shelburne, Massachusetts, specializing in bank locks. In 1868, Yale and Henry Robinson Towne founded the Yale Lock Manufacturing Company in Stamford, Connecticut, to produce cylinder locks. He dies later that year.
There is no connection between Linus Yale and Yale University.