In order to achieve satisfactory defrosting without causing undue wear of the wiper blades equipped with double tongues of elastomer material, the invention provides for first freeing the tongues from the coating of ice by blowing hot air into the duct formed between said tongues, then raising the pivot...http://www.google.se/patents/US4821363?utm_source=gb-gplus-sharePatent US4821363 - Device for washing and defrosting automobile windshields
