Patent ID: 6221189
Filing Date: 2001-04-24
Classification: B29B,B29C,B29D,B29K,B29L

Abstract:
A method of manufacturing thermoplastic tubes from thermoplastic sleeves comprising:providing longitudinally stretched, extruded thermoplastic sleeves having a continuous wall with inner and outer wall surfaces;providing an indexing device rotatable about a shaft;providing forming mandrels mounted on said indexing device for supporting said sleeves;loading each of said sleeves onto each of said forming mandrels in a first location of a closed path, each of said forming mandrels having a head forming end, said loading is carried out by positioning each sleeve over the forming mandrels with an exposed portion of each sleeve having an open end extending beyond said head forming end;advancing said sleeves mounted on said forming mandrels along said closed path in response to rotating said indexing device in a predetermined direction;forming a head on each of said sleeves, by molding thermoplastic material of each of the sleeves, to create tubes in a location of said closed path downstream of said first location, said forming of the head on each of said sleeves to create tubes comprises the steps of:heating the inner wall surface of said exposed portion of each said longitudinally stretched, extruded thermoplastic sleeves by a heat source so that the heated exposed portion shrinks and thickens; andpressing the heated exposed portion with sufficient force into a closure having an interior cavity formed by at least a bottom wall and a side wall comprised of a material that is incompatible with the material from which each said longitudinally stretched, extruded thermoplastic sleeve is comprised so as to form an end on each of said thermoplastic sleeves to conform to the interior cavity of said closure and;forming an orifice in each of said heads during forming of the heads with use of an orifice-forming spike on each of said closures, wherein the closure used during forming of said head functions as said mold cavity and also functions as the closure for the headed thermoplastic tube having a closure on its head such that each of the headed thermoplastic tubes having a closure on its head is formed in a single pressing step;advancing said tubes mounted on said forming mandrels along said closed path in response to rotating said indexing device in a predetermined direction; andunloading said tubes from said forming mandrels in a location of said closed path downstream of said head forming location.