Patent ID: 8246473

Claim:
In a universal joint, having: a first yoke with a first axis of rotation; a second yoke with a second axis of rotation; a housing pivotally connecting the yokes with a pair of cross members, one for each yoke; a centering plate orbitally mounted in the housing between the yokes and slideably connected to an end of each yoke; a lubrication passageway comprising: an arcuate groove in the first yoke, the groove being in a first plane which is spaced apart from the first axis of rotation and is perpendicular to an imaginary line which is normal to the first axis of rotation, the arcuate groove having an entry portion on one side of a second plane which is normal to the first axis of rotation and which intersects the groove where the groove is farthest from the first axis of rotation and the groove having an exit portion on the other side of the second plane; a first passageway in communication with one of the portions for providing lubricant to the groove, the portion being the entry portion; and a second passageway in communication with and extending radially inward from the other one of the portions for directing lubricant from the groove to a sliding surface radially inward from the groove, the portion being the exit portion; wherein the centrifugal force gradient increases from any point in the groove where the second passageway is in communication with the groove to any point in the groove where the groove is farthest from the first axis of rotation; and wherein lubricant is admitted to the universal joint through the groove from the entry portion to the exit portion and then to the second passageway such that backflow through the second passageway due to centrifugal force is impeded by the groove; wherein the improvement comprises: each yoke has a bridge joining arms and a ball head at an inward end of the yoke extending from the bridge; the centering plate has a tube in which the ball heads of the yokes are slideably received to establish the slideable connection between the ends of the yokes and the centering plate; the lubrication passageway has a lubrication bore in communication with the second passageway and extending through the bridge and the ball of the first yoke; and wherein the lubricant is supplied from the second passageway through the lubrication bore to an interior of the tube.