Articulated plunger rod pump

Abstract

A reciprocating rod pump system, comprising an articulating plunger assembly having a plurality of plunger segments, each having a pin end and a box end, and a ball and socket articulating connector formed between the pin end of one plunger segment and the box end of another plunger segment. The articulating connector is formed from a collar rigidly attached to the pin end, which defines a socket, the collar comprising an internal shoulder which abuts an external shoulder on the plunger pin end, such that the uppermost end of the collar does not contact the plunger segment, and a plunger nipple comprising a ball adapted to fit and rotate within the socket, and a shank which rigidly engages the box end thread of a plunger segment.

1 . A reciprocating rod pump system, comprising an articulating plunger assembly comprising:
 (a) at least two plunger segments, each comprising a pin end and a box end, wherein the pin end has an external threaded portion and the box end has an internally threaded portion;   (b) a ball and socket articulating connector, formed between the pin end of one plunger segment and the box end of another plunger segment, which articulating connector comprises:   i. a collar rigidly attached to the pin end, the collar and pin end together defining a socket, the collar comprising an internal shoulder which abuts an external shoulder on the pin end, such that the uppermost end of the collar does not contact the plunger segment;   ii. a plunger nipple comprising a ball and a shank, wherein the ball is adapted to fit and rotate within the socket, and the shank comprises an external thread which rigidly engages the box end thread of a plunger segment.   
     
     
         2 . The rod pump system of  claim 1  wherein the ball comprises a travel limiting abutment which contacts a lower surface of the pin end at the rotational travel limit of the ball within the socket, and the shank and collar are configured so as to not contact each other at the travel limit. 
     
     
         3 . The rod pump system of  claim 1  wherein an inner bore surface on the collar, above the internal shoulder, is close tolerance fitted around an outer surface on the pin end. 
     
     
         4 . The rod pump system of  claim 3  wherein the ball comprises a travel limiting abutment which contacts a lower surface of the pin end at the rotational travel limit of the ball within the socket, and the shank and collar are configured so as to not contact each other at the travel limit. 
     
     
         5 . The rod pump system of  claim 2  wherein the ball comprises a reduced diameter band adjacent the travel limiting abutment. 
     
     
         6 . The rod pump system of  claim 5  wherein the reduced diameter band is located on or about the equator of the ball. 
     
     
         7 . A reciprocating rod pump system comprising a top rod articulating joint for connecting between a reciprocating rod string and a valve rod comprising:
 (a) a rod sub configured to connect to the rod string and having a lower bearing surface;   (b) a swivel sub having an upper bearing surface and lower internal threaded portion and a collar which engages the rod sub to retain the swivel sub, which can freely rotate within the collar;   (c) a rod bushing having a lower end adapted to connect to a valve rod and a threaded upper end which rigidly engages the swivel sub internal threaded portion; and   (d) at least one pin, disposed longitudinally within the swivel sub and the upper end of the rod bushing.   
     
     
         8 . The rod pump system of  claim 7  comprising two pins. 
     
     
         9 . An articulating plunger assembly for use in a reciprocating rod pump system, the plunger assembly comprising (a) at least two plunger segments, each comprising a pin end and a box end, wherein the pin end has an external threaded portion and the box end has an internally threaded portion; (b) a ball and socket articulating connector, formed between the pin end of one plunger segment and the box end of another plunger segment, which articulating connector comprises:
 i. a collar rigidly attached to the pin end, the collar and pin end together defining a socket, the collar comprising an internal shoulder which abuts an external shoulder on the pin end, such that the uppermost end of the collar does not contact the plunger segment;   ii. a plunger nipple comprising a ball and a shank, wherein the ball is adapted to fit and rotate within the socket, and the shank comprises an external thread which rigidly engages the box end thread of a plunger segment.   
     
     
         10 . The plunger assembly of  claim 9  wherein the ball comprises a travel limiting abutment which contacts a lower surface of the pin end at the rotational travel limit of the ball within the socket, and the shank and collar are configured so as to not contact each other at the travel limit. 
     
     
         11 . The plunger assembly of  claim 9  wherein an inner bore surface on the collar, above the internal shoulder, is close tolerance fitted around an outer surface on the pin end. 
     
     
         12 . The plunger assembly of  claim 10  wherein the ball comprises a reduced diameter band adjacent the travel limiting abutment. 
     
     
         13 . The plunger assembly of  claim 12  wherein the reduced diameter band is located on or about the equator of the ball. 
     
     
         14 . The plunger assembly of  claim 9  wherein all plunger segments are identical. 
     
     
         15 . (canceled) 
     
     
         16 . The rod pump system of  claim 4  wherein the ball comprises a reduced diameter band adjacent the travel limiting abutment. 
     
     
         17 . The plunger assembly of  claim 10  wherein an inner bore surface on the collar, above the internal shoulder, is close tolerance fitted around an outer surface on the pin end. 
     
     
         18 . The plunger assembly of  claim 11  wherein the ball comprises a reduced diameter band adjacent the travel limiting abutment.