Rotary vane-type pump

Claim 1

A rotary pump comprising a housing defining an annular passageway and a rotor rotatably mounted in said housing coaxially with said passageway, said rotor comprising a central hollow hub portion and a plurality of vanes carried by the hub portion and disposed in said passageway for movement therein in a circular path, said vanes having the form of flat circular discs on the outer ends of shafts rotatable in said hub portion about axes disposed radially of the axis of said rotor, said passageway of said housing having a pumping portion which is of circular cross section with a diameter equal to the diameter of said circular vanes and a sealing portion of a cross section corresponding to a dimetrical cross section of said vanes with an inlet and an outlet respectively at opposite ends of said sealing portion and means for controlling rotary movement of said shafts to position said vanes orthogonally to said passageway in the pumping portion thereof and in line with said passageway in the sealing portion thereof, said control means comprising an eccentric inward extension of each of said shafts, a cam follower on each of said eccentric shaft extensions, a stationary annular cam concentric with the axis of said rotor and having a single cam surface engageable with said cam follower on one side only thereof and biasing means for urging said cam follower against said cam surface, said biasing means for each vane comprising a bias applying element on said eccentric shaft portion separate from said cam follower and spring means acting between said bias applying element and a fixed seat portion of said hub.