Patent ID: 6227693
Filing Date: 2001-05-08
Classification: B29C

Abstract:
A screw-type machine, said machine including:a plurality of shaft assemblies arranged in parallel, each said shaft assembly having at least one screw element and at least two said shaft assemblies arranged in close proximity so that said screw elements of said shaft assemblies intermesh and,wherein at least one of said shaft assemblies includes:an elongated shaft having opposed first and second ends, said shaft being shaped to have: a first circumferentially extending groove that is spaced from the second end; a second circumferentially extending groove that is located between the second end and the first circumferentially extending groove; and a screw thread located in the second circumferentially extending groove that extends circumferentially around said shaft;at least one said screw element fitted over said shaft between the first end of said shaft and the first circumferentially extending groove of said shaft to move along the length of said shaft and to rotate in unison with said shaft;a stop assembly fitted around said shaft and positioned against said screw element located closest to the first circumferentially extending groove of said shaft, said stop assembly including a stop ring fitted in the first circumferentially extending groove of said shaft, wherein movement of said stop assembly is limited by movement of said stop ring; anda straining ring fitted over the screw thread of said shaft and configured to engage the screw thread for longitudinal movement over said shaft and coupled to said shaft to rotate in unison with said shaft, said straining ring having a face directed towards said stop ring and positioned over said shaft so that the face abuts said stop ring.