A dispensing valve includes an annular ring of relatively rigid molded plastic construction and a flexible resilient valve element integrally molded with the ring. The ring and the valve element have at least one mechanical interlock to secure the valve element to the ring as the valve element is molded...http://www.google.com.au/patents/US7503469?utm_source=gb-gplus-sharePatent US7503469 - Integrally molded dispensing valve and method of manufacture
