Oil pump having pivoting vanes

An oil pump comprising:

• an airtight housing;
• a circular ring fitted in said housing for rotation about a ring axis;
• a driving shaft rotatably mounted in said housing and within said ring for rotation in a direction of rotation about an axis eccentric from but substantially parallel to, and ring axis;
• an inner rotor in said circular ring and mounted to said driving shaft for rotation therewith;
• a plurality of circumferentially spaced vanes, each having an inner end pivotally mounted to said rotor about a pivot axis, each of said vanes being oriented with respect to a radial direction such that said vanes are centrifugally swung radially outward and into contact with said ring in response to rotation of said driving shaft and said inner rotor in said direction of rotation, whereby airtight pump chambers are formed between adjacent ones of said vanes;
• tapered support surfaces on said inner rotor against which said inner ends of said vanes bear, said support surfaces comprising means for limiting a pivoting angle of said vanes such that said vanes will substantially contact said ring when said vanes are at a minimum volume position of said pump chambers;
• and
• intake and discharge ports respectively communicating with said pump chambers at circumferential positions thereof where said pump chambers are expanding and contracting,
• whereby oil from said intake port is pumped by said pump chambers to said discharge port.