In the same spirit as the original thread “What Was He Thinking,” I found an interesting patent for a double-door vault. US patent 1,104,765 by Harry F. Baloun (July 28, 1914) describes an arrangement with two separate doors, one in front of the other.
The outer door is fairly conventional for the round and massive styles, using two combination locks and 24 bolts. It’s mounted on a large crane hinge and has a 3-point pressure system.
What is different is that behind this is a second door, also with 24 bolts, operated purely by a time lock and an automatic bolt motor. This door is not hinged or mounted to the frame in any way (aside from being locked in place by the bolts). Rather, it has a few bolts on the outside that connect it to the inside surface of the outer door. While the doors are closed and locked, these bolts are not connected so that the inner door is no longer connected to the outer door, and opening the outer door only exposes the inner door instead of carrying it along for the ride. Only when the time lock unlocks the inner door will it be connected to the outer door.
This patent is also interesting because it’s the last round-door patent I’ve found.
Were any of these monsters constructed? I can imagine lots of manufacturing issues to get everything lined up and spaced just right.
