Lock Blueprint
On this date in 1889, W. A. Martin, an African American inventor, patented the lock. This device was an improvement over the 4000-year-old bolt invented by the Chinese.
Martin's lock consisted of a cylinder and spiral spring coiled around a metal pin. It was the forerunner of modern door locks.
The Patent number is #407,738 7/23/1889
Created Equal The Lives and Ideas of Black American Innovators
By James Michael Brodie
Copyright 1993, by Bill Adler Books, Inc.
William Morrow and Co. Inc., New York
ISBN 0-688-11536-5
U.S. Patent and Trademark Office
Mail Stop USPTO Contact Center
P.O. Box 1450
Alexandria, VA 22313
