Process for in situ molding of a bearing material in a ball and socket joint assembly

In a process for injection molding a plastic material into an interfacial space between a spherical ball and a spherical cavity of a ball and socket joint assembly to form a plastic bearing, said plastic bearing having an as-molded tapered undercut, said joint assembly including a ball assembly and a socket assembly, said ball assembly including said spherical ball and a neck, said spherical ball having an external surface, and said socket assembly including said spherical cavity, and said process utilizing a molding apparatus including a stationary mold adapted for receiving one of said ball assembly and said socket assembly, a movable mold adapted for receiving one of said ball assembly and said socket assembly and movable towards and away from said stationary mold, and first and second cross-slides, said cross-slides being in sliding contact with said stationary and movable molds, said cross-slides being adapted for slidably moving in response to and in a direction perpendicular to the movement of said movable mold, and said cross-slides being contactable with said ball and socket joint assembly when said spherical ball is positioned within said spherical cavity, an improvement, comprising the steps of:

• selecting a sacrificial ring having a preselected outer diameter, a generally triangular cross-sectional shape, said sacrificial ring being separable into two or more semi-circular portions, said ring having first, second and third sides, and said ring being formed from a material dissimilar from said plastic bearing material;
• positioning said ball within said spherical cavity and forming an interfacial space therebetween;
• placing said sacrificial ring around said ball, said first side of said ring being in contact with the external surface of said ball, said second side of said ring being in sliding contact with said cross-slides when said cross-slides are urged towards said ball and socket assembly, and said third side of said ring forming a tapered end for confining said interfacial space;
• closing said molding apparatus by urging said movable mold towards said stationary mold, and urging said cross-slides towards each other and towards said ball and socket joint assembly;
• rigidly confining said sacrificial ring between said ball, said cavity, and said cross-slides;
• injection molding said plastic material into said interfacial space and forming a plastic bearing having a tapered undercut which mimics the shape of said third side of said sacrificial ring, and;
• opening said molding apparatus and removing said sacrificial ring, thereby providing said ball and socket joint assembly having said plastic bearing with said tapered undercut.