Thrust bearings are old in the art; however, insofar as is known, a thrust bearing which will function frictionlessly under both low and high loading is not available. Referring specifically to some of the known thrust bearing structures, Peterson U.S. Pat. No. 359,030 shows a shaft supported for rotation about a vertical axis on a ball bearing with a flat pellet of bronze interposed between the end of the shaft and the ball. The pellet is comprised of steel and an oil hole is provided in the support to supply oil to the bearing. Due to the thinness of the pellet and its small frictional contact with the ball, very little heat is developed and such heat as is developed is taken away by the oil.
Johansson U.S. Pat. No. 405,559 shows a structure wherein a shaft is supported for rotation about a vertical axis in engagement with a ball bearing so as to be slightly eccentric to the longitudinal axis of the shaft. An insert or plug is interposed between the end of the shaft and the ball bearing. The eccentricity of the insert constantly shifts the ball relative to the shaft so as to present new points to receive the wear.
Springer U.S. Pat. No. 588,117 shows a shaft supported for rotation about a vertical axis on a steel ball recessed into its lower end.
Shields U.S. Pat. No. 867,428 shows a shaft supported for rotation about a vertical axis resting on a ball bearing with a conical insert interposed between the shaft and the ball bearing.
Larrabee U.S. Pat. No. 931,069 shows a shaft supported for rotation about a vertical axis supported on a ball bearing comprised of hard rubber with a rubber insert interposed between the shaft and the ball bearing. Such a structure is limited in its load capacity.
Perkins U.S. Pat. No. 1,059,313 shows a shaft supported for rotation about a vertical axis on a ball bearing which is held tightly engaged to the shaft to cause the ball to rotate with the shaft.
Anderson U.S. Pat. No. 2,216,726 shows a shaft supported for rotation about a vertical axis resting on a ball bearing, the lower end of the shaft being provided with an annular recess to cause the ball to roll around the axis of the shaft as the shaft rotates.
While all of the aforesaid patents disclose broadly the concept of supporting a shaft for rotation about its longitudinal axis on a ball bearing, none of the bearings are designed or adapted to accommodate both low and high loading with an equal degree of frictionless support. It is the purpose of this invention to provide a low and high capacity thrust bearing which will function with equal efficiency under all conditions of loading.