unlocked

keychain-01.png
keychain-01.png

unlocked

from 300.00

in 1889, W. A. Martin, 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.

Reference:
U.S. Patent and Trademark Office
Mail Stop USPTO Contact Center
P.O. Box 1450
Alexandria, VA 22313

 

 

Print Sizes

(S): 8.5x11 in
(M) 24x36 in
(L) 30x40 in
(XL) 60x40 in

Printed on High Quality Archival Metallic Paper

Hand signed and numbered.

Ships within 14 days of purchase 

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