Patent ID: 6382950
Filing Date: 2002-05-07
Classification: B29C,Y10S

Abstract:
A machine for forming helical coil from a heated elongate plastics material comprising:an elongate cylindrical mandrel onto which the material is wrapped in helical formation which is rotatable about its longitudinal axis; a stationary helical guide coil, detached from the mandrel, wrapped around the mandrel and defining a helical guide path around the mandrel between turns of the helical guide coil into which path the material is guided for setting into a helical shape having a diameter determined by the diameter of the mandrel and a pitch determined by the pitch of the helical guide coil; at least two drive rollers parallel to the axis of the mandrel which are rotatable each about a respective longitudinal axis for applying an outer driving force to an outside of the helical coil of plastics material while it is wrapped around the mandrel and while the mandrel applies an inner driving force to the inside of the helical coil of plastics material such that the inner and outer forces tend to drive the material helically along the mandrel from a supply to a discharge end of the mandrel; a drive coupling member at one end of the mandrel for receiving a drive from a rotatable drive member; a mounting boss for supporting the mandrel so as to allow rotation of the mandrel while holding the mandrel against longitudinal movement; a coil support plate having one edge attached to the turns of the helical guide coil so as to support the helical guide coil along its length with the plate extending outwardly of the axis of the mandrel; and a support member for supporting the coil support plate at positions along its length; the coil support plate being readily releasably connected to the support member so that the helical guide coil and the coil support plate can be removed leaving the mounting boss and support member in place for ready replacement of the helical guide coil by a guide coil of a different pitch.