Apparatus and method for manufacturing tubular member

An apparatus for manufacturing a tubular member by continuously supplying a plurality of elongate flexible webs while positionally displacing the webs in overlapping relation with side edges thereof arranged in a staircase configuration, progressively bending the webs along a mandrel, bonding the webs with adhesive layers interposed therebetween to form a tubular member, and joining the displaced side edges t complete the tubular member, said apparatus comprising:

• a device for continuously supplying an innermost one of said elongate webs having a thermally fusible layer on a surface thereof facing the mandrel, while longitudinally tensioning said innermost web;
• a mandrel disposed to lie at an intermediate position between opposite side edges of said innermost web and having an outer circumferential dimension shorter than the distance between the opposite side edges of said innermost web;
• a shaping/guiding device having a pair of semicylindrical shaping/guiding members for bending said innermost web along said mandrel into a tubular body, said shaping/guiding members being movable toward and away from said mandrel and having lower edges disposed in confronting relation to each other at an intermediate position between the opposite side edges of said innermost web and upper edges disposed in confronting relation to each other for receiving between them the opposite side edges of said innermost web;
• a fusing device for pressing with heat the opposite edges of said innermost web which project between said upper edges of the shaping/guiding members to fuse the confronting thermally fusible layers to join the opposite side edges;
• an adhesive coating device for coating a hot-melt adhesive to an outer surface of the joining opposite side edges;
• and a pressing device for pressing the outer surface coated with the hot-melt adhesive against an outer surface of the tubular body.

An apparatus for manufacturing a tubular member by continuously supplying a plurality of elongate flexible webs while positioning displacing the webs in overlapping relation with side edges thereof arranged in a staircase configuration, progressively bending the webs along a mandrel, bonding the webs with adhesive layers interposed therebetween to form a tubular member, and joining the displaced side edges to complete the tubular member, said apparatus comprising:

• a device for supplying the elongate webs in mutually spaced-apart relation while longitudinally tensioning the webs, each of the webs having a hot-melt adhesive applied on at least one surface thereof;
• a mandrel disposed to lie at an intermediate position between opposite side edges of an innermost one of said webs and extend along the webs;
• a device having a plurality of rollers each having a pressing surface complementary to a portion of an outer circumferential surface of the mandrel for pressing the webs against the mandrel, said rollers being positionally displaced from each other longitudinally of said mandrel and angularly about the axis of said mandrel with longitudinally successive rollers having their pressing surfaces partly overlapped circumferentially about said mandrel for progressively enlarging the bonded area between the webs;
• and a device for heating the hot-melt adhesive after the application thereof to said webs to keep the same in a melted condition at least until the webs reach said rollers.

An apparatus for manufacturing a tubular member by continuously supplying a plurality of elongate flexible webs while positionally displacing the webs in overlapping relation with side edges thereof arranged in a staircase configuration, progressively bending the webs along a mandrel, bonding the webs with a hot-melt adhesive applied to the webs to form a tubular member, and joining the displaced side edges to form a joined area and complete the tubular member, said apparatus comprising:

• means for heating said hot-melt adhesive after it has been applied to said webs for keeping the same in a melted state;
• and a cooling mandrel for guiding the completed tubular member fitted thereover;
• a withdrawing device for withdrawing the tubular member along said cooling mandrel;
• and a cooling body disposed in a position confronting the joined portion of the passing tubular member, for abutting against the joined against the joined portion of the tubular member.

A method for manufacturing a tubular member comprising the following steps;

• continuously supplying a plurality of elongated flexible webs in a mutually spaced-apart relationship while longitudinally tensioning the webs;
• positionally displacing the webs in overlapping relationship until the side edges thereof are arranged in a staircase configuration;
• transversely supporting the webs along the lower surfaces thereof by means which enables moving opposite side edges of the webs vertically and toward and away from each other while maintaining the spaced-apart relationship of the webs to progressively bend the supported webs about an outer peripheral surface of a mandrel;
• bonding the webs with adhesive layers interposed between the webs to form the tubular member;
• and
• joining the displaced side edges to complete the tubular member.

A method for manufacturing a tubular member comprising the following steps:

• continuously feeding a U-shaped web having a water-resistant gas barrier surface and a plurality of paper webs in a mutually spaced-apart relationship, while longitudinally tensioning the webs;
• heating the paper webs so that they are uniformly dried;
• positionally displacing the webs in overlapping relationship until the side edges thereof are arranged in a staircase configuration;
• coating the mutually confronting surfaces of the webs with a hot-melt adhesive;
• heating the hot-melt adhesive coating webs to maintain the adhesive in a melted condition;
• further positioning the webs for accurately positioning the side edges of the webs;
• bending the U-shaped web along a mandrel to form an innermost tubular member;
• bending the plurality of paper webs along said mandrel to form with said U-shaped web a composite tubular member;
• and
• cutting the composite tubular member into a desired length.

A method for manufacturing a tubular member by continuously supplying a plurality of elongate flexible webs while positionally displacing the webs in overlapping relation with side edges thereof arranged in a staircase configuration, progressively bending the webs along a mandrel, bonding the webs with adhesive layers interposed therebetween to form a tubular member, and joining the displaced side edges to complete the tubular member, said method comprising the following steps:

• continuously supplying an innermost one of said elongate webs having a thermally fusible layer on a surface thereof facing the mandrel, while longitudinally tensioning said innermost web, said mandrel being disposed to lie at an intermediate position between opposite side edges of said innermost web and having an outer circumferential dimension shorter than the distance between the opposite side edges of said innermost web;
• bending said innermost web along said mandrel into a tubular body by moving shaping/guiding members toward and away from said mandrel, said shaping/guiding members having lower edges disposed in confronting relation to each other at an intermediate position between the opposite side edges of said innermost web and upper edges disposed in confronting relation to each other for receiving between them the opposite side edges of said innermost web;
• pressing with heat the opposite side edges of said innermost web which project between said upper edges of the shaping/guiding members to fuse the confronting thermally fusible layers to join the opposite side edges;
• coating an outer surface of the joined opposite side edges with a hot-melt adhesive;
• and
• pressing the outer surface coated with the hot-melt adhesive against the outer surface of the tubular body.

A method for manufacturing a tubular member by continuously supplying a plurality of elongate flexible webs while positionally displacing the webs in overlapping relation with said edges thereof arranged in a staircase configuration, progressively bending the webs along a mandrel, bonding the webs with adhesive layers interposed therebetween to form a tubular member, and joining the displaced side edges to complete the tubular member, said method comprising the following steps:

• supplying the elongate webs in mutually spaced-apart relation while longitudinally tensioning the webs, each of said webs having a hot-melt adhesive applied on at least one surface thereof;
• said mandrel being disposed to lie at an intermediate position between opposite side edges of an innermost one of the webs and extending along the webs;
• pressing the webs against the mandrel with a plurality of rollers, each having a pressing surface complementary to a portion of an outer circumferential surface of the mandrel, said rollers being positionally displaced from each other longitudinally of said mandrel and angularly about the axis of said mandrel with longitudinally successive rollers having their pressing surfaces partly overlapped circumferentially about said mandrel for progressively enlarging the bonded area between the webs;
• and
• heating the hot-melt adhesive after the application thereof to said at least one surface to maintain the same in a melted condition at least until the webs reach said rollers.