自動天地栓
Inactive door locks automatically when the active door is closed; Inactive door unlocks automatically when the active door is opened.
Jean Wu
半自動天地栓
Opening the active door + Manually unlatching the top bolt = inactive door is accessible; Closing the inactive and active door leaf in sequence = inactive door is secured.
手動天地栓
Switching the lever/snib upward to unlock, downward to lock; You now have access control of the inactive door in your fingers.