You want a pulley system?
I don't understand what you want.
Could you post a picture of the item in question? That would make this easier to understand what you have to work with.
Metal grates on a fan? Do you mean the fan covers on old table or floor fans? You'd have to start from scratch since no electrical. Look at you tube videos,on how to make industrial chandeliers. Maybe you'll find some ideas there.
Do you want to make a separate hanging swag lamp, or a shade for an existing ceiling mounted bulb?
Pictures would really help us to answer your DIY question. If possible, post pictures of the fan with the grates and the place where you want to hang your light. I'm sure we can help you but pictures would help.