What is the best system for lifting things without pistons? I am building a big walker thing. It has a mining laser at the bottom that can be lifted on one half, and the other is attached to the vehicle. 

However, I can't seem to find a way, because the hooks attached to the strings come off to easily. The studs are also facing down and I am not using Mindstorms. 

I'm looking for a purely LEGO solution.
Screwjacks!

Key components would be Technic, Gear Rack 1 x 4 and Technic, Gear Worm Screw

Application of said parts are left as an exercise for the reader, though since OP says they're not using Technic, this might be a moot answer.