A dispensing valve for liquid containers of the type which is normally actuated by a resiliently flexible concave diaphragm to automatically close or self-seal it but which can be manually opened a toggle arrangement including an actuating lever or tab extension projecting outwardly from the concave...http://www.google.es/patents/US4169548?utm_source=gb-gplus-sharePatente US4169548 - Flexible dispenser valve
