Rotary pumps of the eccentric-screw type

1,146,018. Universal joints. OSOBOE KONSTRUKTORSKOE BJURO PO PROEKTIROVANIJU ISSLEDOVANIJU I VNEDRENIJU BESSHTANGOVYKH NASOSOV. 22 March, 1966, No. 12501/66. Heading F2U. [Also in Division F1] In a rotary pump, each of two universal couplings (14, 141), Fig. 1 (not shown), comprises a pair of members or heads 17 connected to each other by an elastic element, e.g. a steel cable, 24, so as to render the joint capable of transmitting tensile forces, which element extends through a hollow rod 25 having partspherical ends 26 that engage with recesses 27 of similar shape within the heads 17 whereby the joint can transmit compressive forces, torque being transmitted from one head to the other by a tubular member 19 and a plurality of axially-orientated cylindrical keys or rollers lodged in keyways 21, 23 of corresponding shape within the heads and the member 19, respectively, which keys are of lesser diameter than the keyways so as to permit a limited lack of axial alignment of one head relative to the other. Screw-threads 18 are provided in the heads 17 to permit connection of either screw rotors (13, 131), or the rotor (131) and a driving shaft (4), thereto. Flexible tubes or cups 28 seal the ends of the member 19. Cooling is effected by fluid, e.g. oil, that is being pumped entering the member 19 through a port 29 and a filter or strainer 30.