I used to work in an old mill (NW UK) converted to industrial units and we got to the top floor using an old lever operated lift. The lever had three positions,

I used to work in an old mill (NW UK) converted to industrial units and we got to the top floor using an old lever operated lift. The lever had three positions, up, down, and stop. The door was a couple of sets of sliding gratings. I seem to recall that there was a locking system but I can't quite recall what it was. It was either that here was some sort of piece of metal that stuck out from the lift shaft and only allowed the doors to be opened at certain positions in the shaft, or that the lift wouldn't operate without the doors being closed, or some combination of both.