Importance

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Abstract

A system and method for fixedly securing a roller side bearing assembly to the top surface portion of a rail car truck assembly. Elongated threaded fasteners pass through registered openings in a bearing cage bottom wall and truck assembly top surface portion in threaded receipt by locknuts disposed on the underside of the top surface portion. A washer captured on each fastener includes at least a portion thereof which is closely interposed between the fastener head and the bearing cage bottom wall at the associated opening. The fasteners are rotated into threaded advancement with the locknuts to achieve fastener clamploads which fall within predetermined upper and lower limits. Each fastener head advantageously includes a hex type wrench receiving opening which has a limited maximum torque capacity generally correlated to obtaining a fastener clampload no greater than the predetermined upper limit. The washer geometry facilitates use of better or improved fastener head fillets. In addition, the fasteners advantageously have undersized bodies or shanks immediately adjacent the heads to reduce bending stresses experienced therein. The overall structural features and manner of installation provide a fatigue resistant, somewhat torque limiting roller side bearing mounting system and method. The results obtained enable the fasteners to withstand periodic bending loads applied thereagainst during normal rail car use.

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First Claim