The Padlock Patent Archive

Three centuries of keeping things shut

Flat key

Patent drawing sheet showing seven numbered figures of a round padlock body with an oscillating bolt frame, notched sliders, a slotted flat key, and cross-sections revealing internal locking mechanism.IMPROVEMENT IN PADLOCKS, &c.Wilson Bohannan · August 6, 1867Patent drawing of a hasp lock showing a hinged latch-hook engaging a staple, a lock-case with internal spring-loaded bolt and multiple lever tumblers, and a flat key used to release the mechanism, illustrated in five labeled figures with a signature block for inventor Joseph S. Elliott.IMPROVEMENT IN HASP-LOCKSJoseph S. Elliott · May 12, 1868Patent drawing of a heart-shaped padlock interior mechanism alongside detailed views of a rotating key-hub and matching flat key with a bit-receiving slot.IMPROVEMENT IN PADLOCKSWilliam Wilcox · January 27, 1874Patent drawing of a round padlock showing six figures: the shackle and tumbler mechanism in locked and unlocked states, an exploded view of the lifted mechanism, a front elevation of the assembled lock, an edge view of the case, and a flat sheet-steel key shown from front and edge.IMPROVEMENT IN PADLOCKSFredrick Egge · July 14, 1874Patent drawing of a padlock showing its rounded U-shaped shackle, internal bolt mechanism in cross-section, lock cover with a cross-shaped keyhole, and two distinct flat keys used to operate the locking bolts and an independent shackle-retaining bolt.IMPROVEMENT IN PADLOCKSLouis Hillebrand · July 23, 1878Patent drawing sheet showing a heart-shaped padlock with internal spring tumblers, a hinged shackle, and two flat keys with stepped bits, labeled with reference letters for the case, dog, tumblers, and springs.IMPROVEMENT IN PADLOCKSWilliam Baldwin · November 19, 1878Patent drawing of a shield-shaped bicycle lock showing internal tumblers and bolts, a U-shaped hasp passing through the lock body, and a mounting clamp attaching the lock to a bicycle's steering head with the hasp threaded between wheel spokes.BICYCLE-LOCK.Edwin W. Macauley · August 23, 1892Patent drawing of a padlock showing the case interior with pivoted shackle, swinging dog, three concentric tumblers, and a flat multi-winged key, alongside detail views of each tumbler and ward-plate.PADLOCK.Henry G. Voight · January 31, 1899