US Patent 173,121 · 8 Feb 1876

Time attachment for locks

by Henry Gross, Cincinnati

Patent drawing of a time lock with two clock dials mounted above a two-wheel combination lock, labelled H. Gross, Time-Attachment for Locks, No. 173,121, patented Feb. 8, 1876
Hover to magnify · click for full screen
Henry Gross's time attachment for locks, US patent 173,121 (8 February 1876), the design behind Hall's early time locks. US patent drawing, public domain.

DownloadSave to Pinterest

Same maker or decade

1867 Dovetailed door and casing

1872 Spherical safe with revolving door

1873 Crank-pin safe-door hinge

1873 Spherical burglar-proof safe

1875 Fire-proof safe filling

1877 Twin-movement time lock

← 1875 Fire-proof safe filling All patents 1877 Twin-movement time lock →