Patent ID: 8316928

Claim:
In a downhole progressive cavity pump, a drive means comprising an input shaft and an output shaft, the input shaft being coupled to a means of rotation, the output shaft being coupled to a rotor of the progressive cavity pump, the input shaft and the output shaft being non-collinear so that the output shaft rotates about an axis of the output shaft while describing a circular path with respect to the input shaft, wherein the input shaft and output shaft are coupled by a male inner rotor and a female outer rotor, the rotors being coupled by a group of interengaged projections, the said projections consisting of n first projections and n+1 second projections, the male inner rotor comprising the first projections, the female outer rotor comprising the second projections, the second projections of the female outer rotor extending radially inwardly to engage the first projections of the male inner rotor and transmit torque from the input shaft to the output shaft; and the male and female rotors being operatively positioned within a housing having at least one eccentric bearing for constraining at least one of the input shaft and the output shaft.