Patent ID: 8851162

Claim:
An end fitting for a sucker rod comprising: an exterior surface, a closed end, an open end, and an interior surface, the interior surface comprising a wedge system defining a cavity, wherein the wedge system comprises three wedge shaped portions having an apex, a leading edge and a trailing edge, each apex forming a perimeter of equal dimension within the cavity that is the narrowest part of the cavity associated with each wedge shaped portion such that the leading edge is longer than the trailing edge with the leading edge facing the open end and the trailing edge facing the closed end with respect to each wedge shaped portion, wherein the leading edge is shorter at the closed end and increases progressively from the closed end to the open end thereby compensating for a compression of the sucker rod in the end fitting, the trailing edge is shorter at the closed end and increases progressively from the closed end to the open end thereby compensating for a back pressure associated with the sucker rod in the end fitting, wherein the first wedge shaped portion is proximate to the closed end and receives compressive forces that are greater than the compressive forces which the second wedge shaped portion receives, and wherein the second wedge shaped portion receives compressive forces that are greater than the compressive forces which the third wedge shaped portion receives, such that the compressive forces create a force differential along the wedge system greater at the closed end of the fitting and decreasing toward the open end of the fitting.