Another year, another patent for the ever eager Oscar Egg. This patent appears to cover a design incorporating a detensioning device - so that you can reduce the chain tension when you want to change gear. I believe that Super Champion introduced just such a thing on the 1937 Super Champion Tour de France.
Note also that the chain tensioning arm attaches to the chainstay. This was typical of earlier Super Champion models - later models had the tensioning arm mounted on the down tube.