Swivel joint with uniform ball bearing requirements
A swivel joint has uniform ball bearing requirements for all bearing races. The swivel joint has a male connector and a female connector that coaxially interconnect and swivel relative to each other. Each connector has three bearing races to form three sets of bearing races, each of which supports that same number of ball bearings. The circumference of the main set of races are enlarged by less than the diameter of one ball.
1. In combination with a swivel joint forming a flow passage and having a central axis, the improvement comprising:
a hollow tubular male connector having a first end, an annular outer surface having a main bearing race, a center bearing race, and a support bearing race, wherein each of the main, center and support bearing races having an arcuate cross-section of a same radius, and wherein the main bearing race's diameter relative to the central axis being the same as the center bearing race's diameter and less than the support bearing race's diameter, the support bearing race being furthest from the first end than the main and center bearing races and the main bearing race being closest to the first end;
a hollow tubular female connector having corresponding female main bearing race, female center bearing race, and female support bearing race adapted to receive and fit around the outer surface and the main bearing race, the center bearing race, and the support bearing race of the male connector to respectively form main, center, and support bearing cavities having a substantial circular cross section of the same cross sectional diameter;
a raised step circumscribing the male connector between the support bearing race and center bearing race, the raised step defining a change of diameter with respect to the central axis to increase the male connector's wall thickness near the male support bearing race;
a recess step in the female connector, the recess step corresponding to the raised step and increasing the female connector's wall thickness near the female main bearing race and the female center bearing race; and
a same number of balls having a same outer diameter in each of the main, center, and support bearing cavities, such that the support bearing cavity holds the same number of balls to a full capacity that no additional ball of the same outer diameter can be placed into each of the main, center, and support bearing cavities, wherein the same number of balls being supported only by the races and themselves.