There's no detent on the blade. It's not a conventional spring, but a bar that flexes, though the dynamics are the same. The blade stays in the closed position because the bar flexes and forces it closed. The movement of the bar is limited by a cutout in the scales. If you remove the bar, the blade is basically just swinging on the pivot.
Kershaw can explain how it works much better than I could. But when I took mine apart when it wouldn't snap open anymore, that's what I came up with. By the way, the torsion bar on my Scallion developed a crack in it so there was minimal tension. I called up Kershaw and they took care of it immediately. Good service.
Zero