OK T, a quick lesson in tremolos.
A non-locking system would be like a standard Fender Strat fulcrum-styled tremolo. The strings go through the tremolo bridge, but are not locked down at any point. You use the bar, and they are free to shift in and out of tune.
Kahler bass tremolos are of the same idea, but are a cam-based system.
A locking system is something like either a Floyd Rose or Kahler
guitar system. The strings on a Floyd Rose are clamped at the bridge, and also up at the top of the neck using a toplock. Kahlers don't normally clamp at the bottom, but do use a toplock.
The idea is that if you take a guitar, and clamp the strings, the original tension, and tuning, is maintained no matter how much you use the tremolo bar. Since the strings are clamped at their original tension, they should always return to pitch as you use the bar.
My goal is to develop a locking tremolo system for bass. This would involve having the strings clamped at the bridge and at the headstock with a toplock.
See?