Apparatus for forming a stretchable tubular packaging material

Claim 1

An apparatus for producing a stretchable tubular packaging material from elongate foam sheet material and which is adapted to receive and package articles therein, said apparatus comprising means for guiding two advancing sheets of flexible foam sheet material into a contiguous overlying relationship to form overlying layers of the sheet material, means positioned downstream of said guiding means for longitudinally severing the two advancing overlying layers of sheet material along a plurality of parallel lines and fusibly uniting the thusly formed adjacent side edges of the two layers along each of the parallel lines to form the same into a plurality of elongated flattened tubular members, said severing and uniting means comprising a plurality of laterally spaced, relatively thin electrically operable heating elements generally perpendicular to the direction of advance of the overlying layers and positioned to extend entirely through the advancing layers, slitting means for slitting the two advancing overlying layers of the sheet material in a pattern of spaced apart rows of spaced incisions with the incisions of adjacent rows being staggered, said slitting means including a pair of rolls forming a nip therebetween through which said overlying layers pass, one of said rolls having a plurality of axially spaced substantially annular rows of spaced cutting blades projecting radially therefrom, the blades in adjacent annular rows being staggered to form said incisions through the two layers of foam material, spreading means positioned downstream of said slitting means and engaging the interior of each tubular member for spreading opposing halves thereof to insure that they may be thereafter readily separated, and means for advancing the two layers of flexible foam sheet material through said guiding means, and severing and uniting means, and said slitting means.

Claim 2

An apparatus for producing a stretchable tubular packaging material from elongate foam sheet material and which is adapted to receive and package articles therein, said apparatus comprising means for guiding two advancing sheets of flexible foam sheet material into a contiguous overlying relationship to form overlying layers of the sheet material, means positioned downstream of said guiding means for longitudinally severing the two advancing overlying layers of sheet material along a plurality of parallel lines and fusibly uniting the thusly formed adjacent side edges of the two layers along each of the parallel lines to form the same into a plurality of elongated flattened tubular members, said severing and uniting means comprising a plurality of laterally spaced, relatively thin electrically operable heating elements generally perpendicular to the direction of advance of the overlying layers and positioned to extend entirely through the advancing layers, slitting means for slitting the two advancing overlying layers of the sheet material in a pattern of spaced apart rows of spaced incisions with the incisions of adjacent rows being staggered, said slitting means including a pair of rolls forming a nip therebetween through which said overlying layers pass, one of said rolls having a plurality of axially spaced substantially annular rows of spaced cutting blades projecting radially therefrom, the blades in adjacent annular rows being staggered to form said incisions through the two layers of foam material, spreading means positioned downstream of said slitting means and engaging the interior of each tubular member for spreading opposing halves thereof to insure that they may be thereafter readily separated, and means for advancing the two layers of flexible foam sheet material through said guiding means, and severing and uniting means, and said slitting means.