The Padlock Patent Archive

Three centuries of keeping things shut

Pick-resistant lock

Patent drawing of a 19th-century padlock and door lock showing an internal toothed bolt rack, four spring-loaded sliding pieces in a rack box, a special multi-pin key, and adaptations to a rotary door lock and a liquor cask tap lock.LOCK AND KEYWilliam Morrett Williams · December 1, 1840Patent drawing showing four views of a padlock's internal mechanism: three oval-shaped interior views (Figs. 1-3) revealing pivoted bolts, a coiled spring, and the shackle in various locked/unlocked positions, plus a fourth figure showing two separate curved bolt pieces labeled D and C with pivot holes and notches.IMPROVED PADLOCKWilliam Harvey · February 11, 1868Patent drawing of a padlock mechanism showing four figures: a circular lock case interior with pivoting lever tumblers and a curved hasp, a flat sliding key with a toothed bit, and a side view of a similar lock with an alternate curved tumbler arrangement.IMPROVEMENT IN PADLOCKS, &c.Daniel K. Miller · October 28, 1873Patent drawing showing four views of a trunk permutation lock: a scalloped cover plate with tumbler recess, a hinged hasp with numbered dial and knob, the closed locked assembly, and a cross-sectional view revealing internal tumblers and pins.Permutation-Lock.Benjamin F. Kelly · January 11, 1881Patent drawing sheet showing ten figures of a padlock design, including exterior side views, internal mechanism with levers, catches, and springs, individual component plates, a locking-bar assembly, and a specially shaped key with cut-away shank.PADLOCKMartin H. Lutz and Morrow Moore · June 15, 1897