Another random thought about Roger's assistance units. It seems to me that if the leaf springs are soft they will move easily to the point where they encounter Roger's thingies (!). At this moment two things happen. 1. they meet the stiffer resistance but still compressing rubber. 2. The length of the leaf spring is effectively shortened causing it itself to be stiffer in response. So that means that Roger's invention creates a perfect double response spring system. Soft over the initial movement, hardening as the load increases. That may be why they work so incredibly well? Nick
