Consolidated Time Lock Co., Cincinnati, Ohio - 2 movements mounted to Hall Safe and Lock Co. single combination lock, size 4

Dual movement Consolidated time lock mounted to Hall combination five-tumbler lock, c. 1885. The Hall combination lock here is their largest of four sized offered by Hall. The use of a dual movement obviated the need for Consolidated's Infallible system used with their single movement time locks. Therefore the design of the lock's release mechanism is simpler than with the single movement time locks. The expense of an additional time lock movement was deemed worth the cost of the override design incorporated in the Infallible system. However, the single movement design, even though quite successful, was soon eclipsed in the time lock industry with the straight-forward idea of time lock movement redundancy incorporating two or more movements.

This example represented the largest size combination lock offered by Hall and used only on the largest most expensive vaults. Therefore the decoration of the case and even the inner plates was extensive. None of this was, of course, mechanically necessary but was absolutely necessary for marketing reasons. The last two photos show this lock in relation to the next two sizes down, a number two, combination lock using a single movement time lock. About twenty of these large format combination locks are known at this time. 4 3/4"h x 5"w x 25/8"d, case #634, movement #5830, combination lock, 5"h x 8"w x 21/4"d, bolt #6175. file 213