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Spring tumbler padlock

Patent drawing sheet showing twelve figures of a U-shaped shackle padlock, including exterior views, cross-sections revealing internal tumbler plates C and springs H, the key F, and a rotating guard plate L covering the keyhole.

PADLOCK.William F. Troast · July 24, 1888

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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