Neck ring assembly for automatic blow molding machines

A rotatable ware supporting neck ring assembly for a blow molding machine comprising in combination:

• a horizontal support member;
• an annular bushing mounted for rotation on a vertical axis of said support member;
• a plurality of segments each having a foot portion which in the closed, ware supporting position of the assembly are in intimate contact with each other and with said bushing and substantially coextensive with the undersurface of said bushing, each of said segments being pivotally supported with respect to, and spring biased radially outwardly of, said bushing;
• means defining a radially inwardly opening annular groove in the adjoining inner surfaces of said bushing and said segments;
• means defining a first cam surface inclined to the vertical on the radial outer surface of each of said segments;
• means defining a second cam surface with is annular, rigidly carried by said support member and engaging the cam surfaces of each of said segments;
• means mounting said bushing and segments for sliding vertical movement on said support member between upper and lower positions with respect to said second cam surface so that in the upper of said positions, said segments are cammed radially inwardly into tight engagement with each other and with said bushing and in the lower position, said segments are biased out of engagement with said bushing;
• further means biasing said bushing and segments toward the upper of said positions;
• and
• hydraulic means for moving said bushing and segments downwardly against the force of said further biasing means and against the frictional forces between said first and second cam surfaces.