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The Padlock Patent Archive

Three centuries of keeping things shut

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Cadmium-plated chain

Patent drawing showing a curved chain with hook ends looping around a tire and rim, with a detailed cylinder lock and sliding bolt mechanism, plus separate sectional views of the chain links, studs, and lock body.

LOCK MECHANISMColvin L. Johnson · April 21, 1931

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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