Mark Frank | Holmes model 2[2] internal override system, c. 1882 @MarkFrankclocks | Uploaded 1 year ago | Updated May 12 2024
This video demonstrates the Holmes Time Lock Model 2[2] electro-mechanical override system, c. 1882. A few time lock makers wanted to be able to override the mechanical time lock should there be a catastrophic failure of the mechanical timer movements. Usually these timers are in pairs to prevent just such a failure, but given a large enough explosive charge there could be damage to both, thus without an alternative method of putting the lock 'off guard' would result in a lockout. Now the fact is that such a large concussion would probably result in damage to the electro-mechanical override system, but it still was a good marketing tool.

To best of this author's knowledge Holmes was the only company to use an electromechanical design to achieve this. The other company to use an override was the Consolidated Time Lock company, but theirs was a purely mechanical system. There was one other company that introduced an electromechanical system into a mechanical time lock was the Hollar company that used a motor not to override, but to extend, the duration of the time lock past the maximum time on the dials in case of an emergency such as civil disturbance or riot by rewinding them from a control outside the vault.