A comfort sole arranged to be mounted in a shoe extends from the heel portion of the shoe to approximately the arch. The sole has a resilient upward curved portion intermediate the sides thereof in the area of the heel portion to form an air chamber between it and the sole of the shoe. This curved portion...http://www.google.co.uk/patents/US4776109?utm_source=gb-gplus-sharePatent US4776109 - Comfort insole for shoes
