How does that weight adjustment gadget on Cybex weight machines work. There’s the standard stack of weights, and you put a rod into that stack at the weight point you want to lift, and when you lift it lifts all the plates above that point. But there’s a mysterious knob at the top that allows you to add 5, 10, or 15 pounds just by twisting the knob. I’ve looked from every direction I could figure, and from what I can tell you still lift the same plates irrespective of the knob setting. There’s no missing weights left behind.
Sorry if this is too off topic, but I think some of the mechanical experts here might know off hand.