Patent ID: 7121212
Filing Date: 2006-10-17
Classification: B61F

Abstract:
1. A long travel, constant contact side bearing for use in a railway car truck, comprising: a generally rectangular base having opposing side walls, a front wall, and a rear wall; a generally rectangular cup-shaped cap having downwardly extending side walls, a front wall and a rear wall that surround the respective side walls, front wall and rear wall of the base in a telescoping fashion with a predetermined spatial gap therebetween, at least in the fore/aft direction, precisely controlled to be between 0.006″ to 0.046″ to achieve improved control, hunting and wear characteristics; and at least two coil springs provided within the base extending between the base and the cap, the at least two coil springs having a combined load rating between about 4000 to 6,000 lb/in, and a travel length from a loaded static height to a fully compressed solid height of at least ⅝″, wherein the walls of the cap and base are configured so as to retain an overlap at the loaded static height state and allow at least ⅝″ of spring travel length before parts of the cap and base abut each other and prevent further spring travel.