Patent ID: 7896179

Claim:
A knuckle pin retainer for use in coupling rail cars together, said retainer comprising: a pivot pin having a head, an elongate shank extending from the head terminating at a distal end, the shank defining a closed end bore having an opening in an exterior surface of the shank and extending inward terminating prior to exit on a diametrically opposing side of the exterior surface, the bore having a first diameter at the exterior surface and sidewalls extending radially inward and a continuous second diameter along an elongate portion of the bore extending from the sidewalls toward a closed end of the bore, the second diameter smaller than the first bore diameter, the shank exterior surface being substantially continuous and uninterrupted except for the single bore opening, a retaining member axially positioned in the bore having a longitudinal path of travel in the bore, the retainer having a first end, a second end, a spherical shaped nose portion adjacent the first end having a first diameter and a body portion extending from the nose portion having a single continuous second diameter from the nose portion to the second end larger than the nose first diameter, the retaining member first and second diameters are smaller than the bore diameter permitting free rotation of the retaining member in the bore, the portion of the bore in radially surrounding relation to the retainer body portion is substantially continuous in diameter; a biasing member positioned in the bore between the bore closed end and the retainer second end in longitudinal biasing engagement with the second end of the retaining member to normally bias the first end of the retaining member to extend beyond the bore opening and shank exterior surface; and a stop radially extending into the bore to prevent longitudinal separation of the retainer member from the shank.