| abstract |
A progressive cavity drive train which includes a progressive cavity device and a coupling for converting the complex motion of the rotor (12) into simple rotation. The coupling includes two offset shafts (22, 24), coupled to one another by offset lug members (23A, 23B). The drive train can be used to convert fluid pressure into rotation of a drill bit in a drilling apparatus. Alternatively, the drive train can be used to convert driving rotation from a motor or engine into fluid pumping action of the progressive cavity device. |