Abstract: A drive rod string for a progressive cavity pump. The drive rod string includes a plurality of drive rods. Each drive rod has a pair of opposed ends, wherein each end terminates in a frustoconical pin having tapered threading and having a radially extending cylindrical shoulder. A plurality of connectors are provided to connect the drive rods. Each connector is attached to one of the ends of the drive rods, wherein each connector has a pair of opposed frustoconical threaded recesses which extend from a pair of opposed shoulders which mate with the cylindrical shoulders of the frustoconical pins. An internal secondary stop within said connector acts as a positive stop in each connector for the frustoconical pin.

Abstract: A drive rod has pins on each end of its body. Each pin has tapered threading and little or no undercut thereby enhancing its ability to transfer rotational motion through the drive rod string by increasing the surface area through which torque is transferred. The tapering of the threading on the pins allows for connectors having thicker walls. This means the connectors can withstand higher rotational stress. The drive rods and connectors are especially well suited for use with progressive pumps.