Arizona laws actually have changed in the past 2-3 years. And the change was good. If you are 21 and over all knives are legal period. No limits, no restrictions on type, anything can be concealed. You can even carry a gun or a full sized katana and it's all nice and legal. Furthermore, the new laws overrides ("preempts") all local laws.
Only regulation is that, if a cop asks you if you have any weapons, you have to declare you're carrying and what.
Official source, see for yourself: