Because you'd normally move the table, especially on freestanding pillar drills.How isn't not normal use to be able to move the head on a pillar drill?
I thought all decent old pillar drills did.
My kerry, and others I've seen, have a collar under the head to stop it dropping. Assuming the collar is tight, you undo the handle that clamps the head to the column, rotate and raise the head, clamp it back off, then raise up the safety collar.