Vacuumized internal sizing ring assembly and method of use

A vacuumized internal sizing ring assembly for use on a stuffing machine to extract air from a tube-like casing having a closed end, wherein the stuffing machine includes a stuffing horn with an outer surface adapted to support the casing inserted thereon and a discharge end against which the closed end is positioned in preparation for stuffing operation, the sizing ring assembly comprising:

• a sizing ring having an inner mounting surface adapted to conform to the outer surface of the stuffing horn for mounting said sizing ring proximate the discharge end with the casing displaced thereover, a peripheral casing-expanding surface to expand the casing into an open configuration as the casing is withdrawn from the stuffing horn during the stuffing operation, a front surface extending radially from the mounting surface to the casing-expanding surface with the front surface adapted to be positioned toward the discharge end, and a back surface located opposite the front surface;
• and
• vacuum means associated with said sizing ring for extracting air trapped within the casing between the closed end and said sizing ring.