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The Padlock Patent Archive

Three centuries of keeping things shut

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Yale lock manufacturing

Patent drawing of a padlock showing its rounded shackle, tubular metal shell, and internal locking mechanism with lever tumblers, bolt, and springs in cross-section.

IMPROVEMENT IN PADLOCKSWarren H. Taylor · August 5, 1879

United States patent drawings and specifications are works of the U.S. government and are in the public domain — they were never copyrighted. Download them, print them, frame them. Our commentary and descriptions are © 2026 The Padlock Patent Archive.

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