Another example of “what was he thinking,” US patent 1,007,568 by William Hollar, 1911. The idea here is to facilitate a tight seal of a vault door by actively cooling the door (to shrink it) with refrigerant such as liquid carbon dioxide, and electrically heating the frame (to expand it). Once the door warms back up and the frame cools down, you have a very tight fit. Opening the door requires re-cooling it and re-heating the frame. For security, the controls and refrigerant tank can be put inside the vault and actuated by time locks.
Disadvantage: it takes some time to heat and cool this much steel. Preparation for closing can be done in advance, but once the door is closed and locked, it takes time for the temperatures to normalize. The opposite is also true, the heating/cooling needs to be started before opening time. And you need to be sure there’s an adequate supply of refrigerant (and no leaks), else you might not be able to open the vault in the morning.
Disadvantage: I’m not convinced that shrinking/expanding a taper fit would lock it in place, or if it would instead try to force the door and frame apart.
And then there’s the usual, what problem is this trying to solve?
At least it’s entertaining.
