Importance

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Abstract

A container body is simultaneously necked-in and flanged at the marginal edge adjacent to an open end by a tool assembly having first and second freewheeling rollers supporting the inside of the body while a die ring moves eccentrically between the rollers. An encapsulating annular nest ring circumferentially surrounds the open end of the body on the second roller to provide metal control, and the first roller innermost in the body is tapered at its end adjacent the second roller to define, in cooperation with a circumferential container body holder ring on the outside body surface, a volume for receiving metal reverse-flowing from the necked-in portion to prevent the metal from bulging. Compressive forming forces are minimized by the use of springs biasing the two rollers together that are characterized by spring force that increases with increased spring compression at less than a linear rate. Near the conclusion of the necking and flanging process, the neck is subjected to pure tensile forces to draw excess metal from the volume holding reverse-flow metal. A rotary action machine employing the tool assembly employs a spindle for converting linear motion into rotational motion to control the tool assembly operation through relative rotation of eccentrics within the tool assembly. A drag brake prevents rotation of the rollers or die ring with respect to the container body to prevent scratching of protective coatings, while permitting surface-to-surface rolling without slippage between the body and tool assembly components in contact with it.

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First Claim