Tube-making apparatus

Claim 1

Apparatus for making tubes from a roll of generally flat sheet material, comprising means for unwinding the sheet material from the roll and for moving said unwound sheet material along a predetermined path, means for movably mounting the roll so that said roll can move to and fro generally transverse to the sheet''s direction of travel along said path, means connected to the movable mounting means for moving said roll to and fro, means along said path which sense an edge of the unwound sheet material and, in response to a lateral change in the position of the edge being sensed, actuate the roll moving means to return the edge to about its original position, means along said path for folding said unwound sheet material so that its longitudinal edges overlap slightly, said folding means including a. a first guide member at an angle of about 45* with respect to one longitudinal edge of the sheet material and having a first end near said one edge and a second end between said one edge and the central longitudinal axis of the sheet material; b. a second guide member at an angle of about 45* with respect to the other longitudinal edge of the sheet material and having a first end near said other edge and a second end between said other edge and the central longitudinal axis of the sheet material, said first and second guide members being spaced apart but on the same side of the sheet material and sloping so that their second ends are further along the sheet''s path of travel than their first ends; c. a third guide member between and connected to the second ends of said first and second guide members and lying generally perpendicular to the central longitudinal axis of the sheet material; d. a fourth guide member at an angle of about 45* with respect to one longitudinal edge of the sheet material and having a first end near said one edge and a second end between said one edge and the central longitudinal axis of the sheet material; and e. a fifth guide member at an angle of about 45* with respect to the other longitudinal edge of the sheet material and having a first end near said other edge and a second end between said other end and the central longitudinal axis of the sheet material, said fourth and fifth guide members being spaced apart, on the side of the sheet material opposite that of said first and second guide members and subsequent in the sheet''s path of travel to said first and second guide members, and sloping so that their first ends crisscross and are further along the sheet''s path of travel than their second ends, whereby said sheet''s direction of travel as it moves across said first and second guide members is changed to turn said edges inwardly to move toward the central Longitudinal axis of the sheet material, and said sheet''s direction of travel as it moves across said third, fourth and fifth guide members is changed to bring the edges of the sheet into an overlapping position and to move said edges generally parallel to each other; means along said path subsequent to the folding means for applying a sealing material to said overlapped edges and forming a seam along said overlapping edges, and means along said path for cutting the folded and seamed sheet material along a line which is transverse to the sheet''s direction of travel along said path.