| 主权项 |
1. A device for use in association with a polished rod, where the polished rod is used to actuate a progressive cavity pump, said device comprising:
a housing defining an inner passageway for said polished rod to pass through, said polished rod defining a longitudinal axis; and an opposed friction roller assembly within said housing, said friction roller assembly comprising:
at least one pin receptacle extending transverse through said housing towards said inner passageway;a moveable pin mounted within said pin receptacle, said moveable pin being movable between an inner position and an outer position;a first friction roller attached to an inner end of said pin, adjacent to said polished rod, said first friction roller being configured to rotate about a second axis substantially perpendicular to said longitudinal rod axis; anda second friction roller opposed to said first friction roller with said polished rod located between said rollers;at least one of said first and second frictional rollers being sized and shaped to grip said polished rod when said moveable pin is extended inwardly to a polished rod engaging position to reduce rotational movement of said polished rod about said longitudinal rod axis, while permitting longitudinal movement of said polished rod up and down said longitudinal rod axis whereby backspin in said polished rod is reduced. |
