Are stilettos illegal in Illinois?

I'm beginning a knife collection and I already have a bowie knife, balisong, multitool, and some pocket knives, but I would really like to add an automatic knife to my collection. I live in Illinois and I've tried reading the law but it makes no sense at all to me. It seems like they're saying it's illegal to carry a knife with you if you're going to stab someone, but that's pretty obvious. Help me?