Produces Compacted Surface Layer Resisting Fatigue

Author:  Verwerk, Paul Otto Friedrich
Source:  US Patent 1,946,340
Doc ID:  1934001
Year of Publication:  1934
Abstract:  
The present invention resides in the discovery, that by a structural improvement of a very thin superficial layer on the surfaces of springs, the number of oscillations up to fatigue can be increased by 600-1000%.