The gear pump unit (100) comprises a pump cover (1), an internal rotor (16) mounted rotatably in a recess (9) of the pump cover (1) and formed in a rotationally fixed manner on a driven plug-in shaft (11), and an external rotor (19), which is rotatably mounted in the recess (9) of the pump cover (1)...http://www.google.com/patents/US7413424?utm_source=gb-gplus-sharePatent US7413424 - Gear pump and holding element therefor
