Patent ID: 6457966
Filing Date: 2002-10-01
Classification: B29C,B29L,Y10S

Abstract:
An apparatus with multiple operating phases for forming stable and internally regular bell mouths on a terminal junction section of pipes made of thermoplastic material, said apparatus comprising:a first portion comprising radially moving mechanical sectors, said first portion having a length, measured along a longitudinal axis, that is equal to a length of a bell mouth to be formed, said first portion movable from a first extreme retracted position in which the first portion presents a diameter to be freely introduced into the terminal section of the pipe, to a second extreme expanded position which dilates an entire part of the terminal section that surrounds it, thereby forming a temporary bell mouth of maximum dilation defining a temporary inner diameter that corresponds to an outer diameter of said first portion when said first portion is moved to the position of extreme dilation, said temporary inner diameter being greater than a nominal final diameter of the bell mouth to be formed; means for heating said first portion to a temperature that is greater than or equal to that of the terminal section of the pipe, so that the terminal section of the pipe does not release heat during its plastic dilation to form the temporary bell mouth of maximum dilation; a second portion that is geometrically fixed and that includes an outer diameter equal to the nominal inner diameter of the bell mouth that is to be formed, said second portion adapted for introduction into the temporary bell mouth of maximum dilation, after the complete intervention of said first portion which, in the retracted position, allows the free subsequent introduction of said second portion into the temporary bell mouth of maximum dilation, said second portion dimensioned to calibrate exactly an inner diameter of the bell mouth that is to be formed, subject to spontaneous retraction after the previous dilation and comprising means for being cooled below the temperature of the terminal section, thereby rapidly bringing the bell mouth to ambient temperature, once it has reached the nominal final diameter, said apparatus further comprising a third, preliminary intervention portion including a hollow rubber element, expandable from within by inflation from a first rest and minimum size configuration, in which the hollow rubber element presents a lesser maximum diameter than the inner diameter of the pipe whereby said hollow rubber element is enabled freely and preliminarily to be introduced first into the terminal section of the pipe, to a second maximum expansion configuration, in which the hollow rubber element presents a substantially cylindrical shape with diameter ranging between the inner diameter of the pipe and the temporary inner diameter of the temporary maximum dilation mouth, whereby said hollow rubber element is adapted to pre-form a bell mouth of intermediate dilation, into which said first portion will subsequently be able to be introduced to complete a residual dilation until forming said temporary maximum dilation mouth.