Patent ID: 8376616

Claim:
A bearing assembly comprising: (a) an outer cylindrical member having a longitudinal axis, a cylindrical bore, and a cylindrical inner surface into which is formed a first annular recess defining an outer upper shoulder and an outer lower shoulder, said outer upper shoulder and outer lower shoulder being axially spaced apart; and (b) an inner cylindrical member rotatably disposed within the bore of the outer tubular member, said inner tubular member having an outer cylindrical surface into which is formed a second annular recess defining an inner upper shoulder and an inner lower shoulder, said inner upper shoulder and inner lower shoulder being axially spaced apart, said inner tubular member being longitudinally movable within the outer tubular member between: b.1 a first position in which the inner upper shoulder and the inner lower shoulder are displaced below the outer upper shoulder and the outer lower shoulder, respectively; and b.2 a second position in which the inner upper shoulder and the inner lower shoulder are displaced above the outer upper shoulder and the outer lower shoulder, respectively; wherein: (c) the first and second annular recesses, in juxtaposition, define an annular containment chamber for receiving a thrust bearing; (d) the outer upper shoulder is planar and has a first radial width; (e) the inner lower shoulder is planar and has a second radial width; (f) the outer upper shoulder and the inner lower shoulder lie in parallel planes transverse to the longitudinal axis; and (g) the first and second radial widths are symmetrical about a common centerline parallel to the longitudinal axis.