A cleaning device comprises a fluid passage extending through the sheath of a forward view type endoscope and having one end located in the operation section of the endoscope and the other end located in the distal end section of the endoscope; a pump for supplying a fluid through the fluid passage from...http://www.google.com/patents/US4281646?utm_source=gb-gplus-sharePatent US4281646 - Cleaning device for an observation window of an endoscope
