Patent ID: 6220846
Filing Date: 2001-04-24
Classification: B29B,B29C,B29K

Abstract:
Apparatus for expanding and conferring a cup shape to a terminal junction segment of a bi-axially oriented pipe made of thermoplastic material and shaping the terminal junction segment with a circumferential annular seat for housing a corresponding sealing gasket for the terminal junction segment by forced introduction of a calibration expander into the terminal junction segment, comprising:a first furnace having inside it a temperature distribution that uniformly increases with the distance form an inlet of the first furnace for heating the terminal junction segment to a differentiated temperature that increases approaching the end of the terminal junction segment to a maximum temperature (Tmax) prior to the forced introduction of the calibration expander;a station for further heating, circumferential dilation, and thickening by friction of the terminal junction segment prior to the forced introduction of the calibration expander comprising at least a rigid element for circumferentially dilating the terminal junction segment when the rigid element is forcedly and progressively introduce inside the terminal junction segment and for inhibiting retraction of the terminal junction segment during at least action of heating means internal to the rigid element thereby contributing to dimensional stability of the terminal junction segment in such a manner as to favor subsequent forced itnroduciton of the calibration expander, a second furnace for further heating the terminal junction segment, heating means internal to the rigid element for heating thereof, and bilateral clamps for locking the terminal junction segment, wherein the rigid element has a free front end, an opposite end and inner walls, is movable within the second furnace, and has a section that increases progressively and then remains constant;a calibration expander for shaping and expanding the terminal junction segment when fornt end of the calibration expander is forcibly introduced inside the terminal junction segment preventively heated to a plastic state;heating means for healing the calibration expander to a temperature (TM) that is greater than or equal to the maximum temperature (Tmax) located at the end of the terminal junction segment to preventively heat the terminal junction segment; andmeans for cooling at least an outer surface of the terminal junction shaped by the forced introduction of the calibration expander prior to extraction of the calibration expander.