Sucker rod end fittings and method of using same
An end fitting for sucker rods or continuous sucker rods defines a rod receptacle with an interior surface defining void spaces having an axial radius of curvature of at least twenty inches. In one form, the fitting receptacle defines two such void spaces and the radius of curvature differs between them.
1. A sucker rod construction comprising:
an end fitting defining a rod receptacle;
said rod receptacle having an interior wall surface defining a cavity, a closed axially inner end, and an open axially outer end, a plurality of integrally formed, axially aligned, axially spaced void spaces, each being tapered to be of decreasing diameter towards said open axially outer end, said void spaces each defined by a wall surface having a radius of curvature of approximately twenty (20) inches;
a rod having an end with an outer surface received within said rod receptacle through said open axially outer end and cooperating with said interior wall surface to define an annular chamber between said outer surface of said end of said rod and said interior wall surface of said rod receptacle;
a body of initially flowable adhesive cured to bond to said outer surface of said end of said rod and solidified to form a plurality of wedges in said tapered void spaces engaging said interior wall surface of said fitting; and
wherein said entire portion of said rod within said cavity has a cross section other than round.
2. The sucker rod construction of claim 1 , further comprising said interior wall surface defining one of said void spaces defined by said interior wall surface having a radius of curvature greater than the radius of curvature of another of said void spaces defined by said interior wall surface.
3. The sucker rod construction of claim 1 , further comprising, a transition surface between said closed axially inner end and the surface defining said void space distal from said open axially outer end, and a transition surface between said axially aligned, axially spaced void spaces, wherein said transition surfaces have a wave-shaped cross-section.
4. The sucker rod construction of claim 3 , wherein said rod comprises fiberglass.
5. The sucker rod construction of claim 1 , wherein said rod has a substantially polygonal shaped cross-sectional configuration.
6. The sucker rod construction of claim 5 , wherein the rod comprises fiberglass.
7. The sucker rod construction of claim 5 , wherein the rod comprises a composite material.