Substantial Large Folding Key

This
large folding key is made of iron and is likely hand riveted. It folds midway through the shaft. This is a very unusual design for a key of this size. Most keys of this stature do not fold at all. Unfortunately there is a crack in the folding mechanism, but it is probably a very old crack dating back to the era when this key was utilized and may have been part of the key from construction. Possibly used as a gate key.
A view of the key folded:

The other side of the key:

The key folded:

The key partially folded: