Plastic tube corrugator and mold blocks.

摘要

A machine for making plastic tubing including a plurality of separate carriages for carrying mold blocks about the continuous path. First and second wheel pairs on opposite sides of each carriage ride on first and second tracks respectively through a molding section of the path. An offset wheel is disposed between the wheels of each pair and rides on guide tracks associated with and facing oppositely to the first and second tracks respectively through the molding section. Each mold block is a plurality of sub-blocks secured end to end, with each sub-block having an arcuate face and corrugated with not more than one complete wavelength. Vacuum channels about sub-block end surfaces connect the block face to a vacuum port. Cooling water channels about sub-block end surfaces connect to water inlet and discharge ports for selectively circulating cooling water through the blocks. The mold block ports communicate with respective vacuum, water supply, and water discharge channels in a longitudinal supply tray along which the mold blocks travel through the molding section. A mold train drive engages a selected number of carriages at the beginning of the mold tunnel to continuously drive the carriages along the mold tunnel. A shuttle drive follows the continuous path through a shuttle area and spaced from the path along a substantial portion of the mold tunnel, and includes first and second carriage engaging sections at substantially opposite points along the drive so that a carriage at the end of the mold tunnel becomes engaged by one shuttle drive engaging section while the other shuttle drive engaging section engages a carriage at the beginning of the mold tunnel. The shuttle drive accelerates when one of the carriage engaging sections enters the shuttle drive portion spaced from the continuous track path to disengage a carriage at the beginning of the mold tunnel, and decelerates to the speed of the mold train drive as an engaged carriage reaches the beginning of the mold tunnel. <IMAGE>