Railroad car coupler assembly knuckle pin

1. A railroad car coupler assembly knuckle pin comprising:

an elongated cylindrical tubular body having an upper end portion, a lower end portion spaced apart from the upper end portion, and an intermediate portion between and connecting the upper end portion and the lower end portion, the body including an elongated cylindrical wall having an outer surface and an inner surface that defines an elongated central opening that extends the length of the wall, the elongated cylindrical wall including two spaced apart elongated opposing surfaces that define an elongated slot that extends the length of the wall;

an annular first ring integrally connected to and outwardly extending from a first area of the upper end portion of the body; and

an annular second ring integrally connected to and outwardly extending from a second area of the upper end portion of the body, the second ring is spaced apart from the first ring along the body;

wherein the first ring defines a plurality of first stress relief slots, the first ring including four equally sized sections, each section including a curved wall having a top surface, a bottom surface, a concave inner surface integrally connected to the outer surface of the wall of the body, a convex outer surface, a first end surface that partially defines one of the plurality of first stress relief slots, and a second end surface that partially defines another one of the plurality of first stress relief slots.

2. The railroad car coupler assembly knuckle pin of claim 1 , wherein the second ring defines a plurality of second stress relief slots, the second ring including four equally sized sections, each section including a curved wall having a top surface, a bottom surface, a concave inner surface integrally connected to the outer surface of the wall of the body, a convex outer surface, a first end surface that partially defines one of the second stress relief slots, and a second end surface that partially defines another one of the second stress relief slots.

3. The railroad car coupler assembly knuckle pin of claim 1 , wherein the second ring defines a plurality of second stress relief slots, the second ring including four equally sized sections, each section including a curved wall having a top surface, a bottom surface, a concave inner surface integrally connected to the outer surface of the wall of the body, a convex outer surface, a first end surface that partially defines one of the second stress relief slots, and a second end surface that partially defines another one of the second stress relief slots.

4. The railroad car coupler assembly knuckle pin of claim 1 , wherein the first ring is sized diametrically larger than a knuckle pin opening and a coupler pin opening.

5. The railroad car coupler assembly knuckle pin of claim 1 , wherein the second ring is sized diametrically larger than a knuckle pin opening and a coupler pin opening.

6. The railroad car coupler assembly knuckle pin of claim 1 , wherein the body, the first ring, and the second ring are monolithically formed.

7. The railroad car coupler assembly knuckle pin of claim 6 , wherein the body is steel, the first ring is steel, the first ring is welded to the outer surface of the wall of the body, the second ring is steel, and the second ring is welded to the outer surface of the wall of the body.

8. The railroad car coupler assembly knuckle pin of claim 1 , wherein the opposing surfaces that define the elongated slot extend in intersecting planes.

9. The railroad car coupler assembly knuckle pin of claim 1 , wherein the opposing surfaces that define the elongated slot extend in parallel planes.

10. The railroad car coupler assembly knuckle pin of claim 1 , wherein the opposing surfaces that define the elongated slot extend in non-linear planes.

11. The railroad car coupler assembly knuckle pin of claim 1 , wherein the lower end portion of the body defines a plurality of spaced apart aligned fastener receipt holes.

12. The railroad car coupler assembly knuckle pin of claim 1 , wherein the elongated slot is non-linear.

13. The railroad car coupler assembly knuckle pin of claim 1 , wherein the width of the elongate slot is constant.

14. The railroad car coupler assembly knuckle pin of claim 1 , wherein the width of the elongated slot is different in at least two spaced apart locations along the elongated slot.

15. A railroad car coupler assembly knuckle pin comprising:

an elongated cylindrical tubular body having an upper end portion, a lower end portion spaced apart from the upper end portion, and an intermediate portion between and connecting the upper end portion and the lower end portion, the body including an elongated cylindrical wall having an outer surface and an inner surface that defines an elongated central opening that extends the length of the wall, the cylindrical wall including two spaced apart elongated opposing surfaces that define an elongated slot that extends the length of the wall;

a first annular ring integrally connected to and outwardly extending from a first area of the upper end portion of the body, wherein the first ring defines a plurality of first stress relief slots; and

a second annular ring integrally connected to and outwardly extending from a second area of the upper end portion of the body, the second ring is spaced apart from the first ring along the body, wherein the second ring defines a plurality of second stress relief slots aligned with the first stress relief slots;

wherein the body, the first ring, and the second ring are monolithically formed; and

wherein the body is steel, the first ring is steel, the first ring is welded to the outer surface of the wall of the body, the second ring is steel, and the second ring is welded to the outer surface of the wall of the body.