The clamps are not actually clamps. They are alignment brackets to hold all the leafs in alignment with the main leaf.

On a totally separate note. Can not debate the fact some cars have improved their 60' time with a front segment clamped together. It basically makes the forward section a solid bar but their is a big downside to that procedure.

The leafs are meant to slide on each other. Picture an arched set of leafs, when they are compressed flat they bottom ones will grow longer. If they are clamped they are not allowed to slide. Fact is 4000lbs and a dip in the road will force them to slide but the friction set by the clamps will make the suspension have a memory. Push down and it will want to stay down, pull up and it will stay up.