Hollar Lock Inspection and Guarantee Co., Model 2, 1896, time lock demonstration video.

This video demonstrates the Hollar Model 2 introduced in 1896. This time lock used a motor to allow the user to rewind one of the three time locks indefinitely to keep the vault closed after the maximum 72 hours denoted on the timer movement dials. This was thought to be useful in the event of civil disturbance or possible invasion. It was an improvement from their Model 1 that used a massive spring to rewind the timer giving the operator only a few times to rewind the time lock without having to open the vault door to rewind the spring.
One of the issues with this type of design is that under the emergency of the rewinding period, only one movement would be used to keep the time lock on guard - a fundamental violation of having redundancy in the timer movements to prevent a lockout. There were features in this design to remediate this problem and are described at the end of this video as well as the web page.
For a full discussion one can see this time lock at: www.my-time-machines.net/holla...