High torque rotatable progressive cavity drive rods and connectors

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.

1 . A drive rod comprising an elongated body having a pin on each end of said body wherein each said pin has tapered threading.  
     
     
         2 . A drive rod as set forth in  claim 1  wherein said pin is frustoconical.  
     
     
         3 . A drive rod of  claim 1  wherein said pins have substantially no undercut.  
     
     
         4 . A drive rod string comprising: 
 a plurality of drive rods connected by a plurality of connectors wherein said connectors attach to the ends of said drive rods by pins having tapered threading.    
     
     
         5 . A drive rod string of  claim 3  wherein said pins have substantially no undercut.  
     
     
         6 . A method of operating a progressive cavity pump comprising: 
 positioning a progressive cavity pump at the bottom of a well;    attaching a drive rod string having drive rods with tapered threading to said pump; and    rotating said drive rod string thereby rotating said pump.    
     
     
         7 . The method of  claim 6  wherein said rotating of said sucker rod string comprises placing between 1,200 and 1,500 foot pounds of torque to said sucker rod string.