Patent ID: 8764424

Claim:
A screw pump ( 20 ), comprising: at least two screws ( 40 ) having helical flights intermeshing with each other during rotation, and extending between inner and outer ends ( 44 and 42 ); a base ( 26 ); a shaft ( 50 ) for each screw ( 40 ), and extending between an inner end ( 68 ) and an outer end ( 74 ), as well as cantilevered from the base ( 26 ) proximate the inner end ( 68 ); each screw ( 40 ) formed with a hollow core ( 80 ) for receiving the shaft ( 50 ) such that the screw ( 40 ) slips onto the respective shaft ( 50 ) therefor over the outer end ( 74 ) thereof; an axial clamping arrangement ( 56 ) intermediate each shaft ( 50 ) and screw ( 40 ), and operative to rotationally lock the shaft ( 50 ) and without a key or keyway; wherein each shaft ( 50 ) is formed with and instep proximate the outer end, which produces a shoulder ( 74 ); wherein each axial clamping arrangement ( 56 ) comprises a pair of jaws ( 54 and 68 ) connected to or formed on the shaft ( 50 ), wherein at least one jaw ( 54 ) is movable and driven to produce clamping pressure; wherein each movable jaw ( 54 ) comprises a ring ( 54 ) which fits inside the annular cavity between the necked-in shaft ( 50 ) beyond the shoulder ( 74 ) thereof and the core ( 80 ) in the screw ( 40 ) proximate the outer end ( 42 ) thereof; and wherein the movable jaw ( 54 ) is driven by threaded rod engaged to the shaft ( 50 ) at the shoulder ( 74 ).