Apparatus and method for necking tubular members such as containers

摘要

An apparatus and method for necking tubular members such as cans utilizes an inner die that expands to support a neck portion to be formed by an outer die that travels around the neck. The inner die has a plurality of first die elements which may be retracted after the neck is formed so that the inner die may be removed. Selected ones of these first die elements nest with the others in the retracted state. Drive assemblies operate each of the inner and outer dies, and the drive assembly for the inner die operates to differentially drive the first die elements to allow nesting to occur. Preferably, the inner drive assembly employs a reciprocally retracting cam, and the first die elements have cam followers to allow reciprocation. A wedge cam can be used to support the first die element sin the expanded configuration, and a wedge drive moves the wedge cam into and out of position. Mechanical timing is provided, and a plurality of necking apparatus may be mounted in a turret-type machine that includes mechanisms to advance the tubular members to be formed.