| 摘要 |
<p>A corrugated mold block (10) for a vacuum machine for molding corrugated tubes is formed of a plurality of sub-blocks (16) rigidly secured end to end. Each sub-block has an arcuate face which is corrugated (18) with not more than one complete wavelength of circumferential grooves and lands, and two longitudinally spaced end surfaces. A vacuum channel (40) is provided about one of the end surfaces of each sub-block, and openings in each sub-block connect the channel and the face. When the sub-blocks are secured together into a mold block (and when mold blocks abut during molding), the vacuum channels and openings together define vacuum passages for each of the corrugation grooves, which passages are all connected to a vacuum source for drawing a vacuum during molding. <IMAGE></p> |
