A progressive cavity device with drive connections at both ends

A progressive cavity pump or motor for use downhole comprises a Moineau type power section with a helically lobed rotor 40 within a helically lobed stator 44 having one more lobe than the rotor. In order that the device may drive or be driven by a main motor or load and an auxiliary motor or load the rotor has a rotating motion drive connector at both ends. One or both of the connectors may be a shaft 82 with two universal joints, a flexible shaft or a non-nutating drive 80 which may comprise a planetary gear or crank disc that receives drive from nutation of the rotor. As the rotor nutates once per rotation per lobe it nutates faster than it rotates thus the non-nutating drive may act as gearing and match a faster turning electric motor to a slower pump. The twin mechanical connection allows a downhole progressive cavity device to provide drive to an auxiliary such as crushing, fluid mixing/shearing and reaming devices or a generator for downhole electrics.