Sargent and Greenleaf
Sargent and Greenleaf, more commonly known among Safe and Vault technician circles as S&G, is a U.S. company that manufactures combination locks, key-operated safe and safe deposit box locks, high security military padlocks, and associated equipment.
The company was established in 1856 when James Sargent and Halbert Greenleaf became partners. A manufacturing facility was built in Rochester, New York, and the company remained in that city until 1975. Since then, the company has been in Nicholasville, Kentucky.
S&G locks are used throughout the US railroad industry on high security applications such as for locking locomotive cabs and important main line switches. These high security locks are sold around the world through associated distributors.
Notable innovations
In 1857 Sargent had designed the Sargent's Magnetic Bank Lock, said to be the first successful key changeable combination lock.
In 1873 Sargent created the first time lock, using parts from eight-day clocks.
In 1880 Sargent connected one of his combination locks to a delay timer, creating the first time-delay combination locks.