Machine and method for applying tubular shrink sleeve material to objects
A machine for applying tubular film to objects includes a mandrel about which a tubular film is passed, a perforation assembly for forming a perforation line across a width of the tubular film prior to the tubular film moving onto the mandrel, and a sleeve ejection arrangement associated with the mandrel to separate the tubular film along the perforation line to create a tubular sleeve that is ejected off of the mandrel and onto an object. The perforation assembly includes a perforation unit mounted for movement across the width the tubular film, the perforation unit including a perforation blade that is rotated over the tubular film, to apply the perforation line, as the perforation unit moves across the width of the tubular film.
1 . A method of forming perforation lines across a width of a tubular film, the method comprising:
providing a machine that separates sleeve-shaped film sections from the tubular film and applies the sleeve-shaped film sections to objects;
utilizing a perforation unit that includes a perforation blade mounted for rotation about an axis;
feeding the tubular film along a film path toward a mandrel of the machine;
stopping the feeding of the tubular film;
while the feeding of the tubular film is stopped, moving the perforation unit across the width of the tubular film while the perforation blade is engaged with the tubular film such that the perforation blade is rotated about the axis and over and in contact with the tubular film, to apply a perforation line that is defined by a series of through cuts in the tubular film, as the perforation unit, including the axis, moves across the width of the tubular film;
wherein the perforation unit is coupled to be moved by a drive associated with a control system of the machine, and the control system automatically carries out the feeding, stopping and moving steps.
2 . The method of claim 1 , wherein the perforation blade presses against the tubular film and a plate member behind the tubular film to cause rotation of the perforation blade about the axis as the perforation unit moves across the width of the tubular film.
3 . The method of claim 2 , wherein the plate member is positioned within a guide block through which the tubular film extends and through which the tubular film moves during the feeding, wherein the guide block includes a side slot facing the perforation unit, and the perforation blade extends through the side slot to engage the tubular film and the plate member.
4 . The method of claim 1 , wherein the perforation blade includes a series of peripheral teeth that sequentially engage with the tubular film to perforate the tubular film and apply the perforation line.
5 . The method of claim 1 , wherein the perforation unit is moved in a first direction to apply the perforation line, the method further comprising:
after application of the perforation line, advancing the tubular film along the feed path;
stopping the advancing of the tubular film; and
after stopping the advancing the tubular film, moving the perforation unit across the width of the tubular film in a second direction, opposite the first direction, while the perforation blade is engaged with the tubular film such that the perforation blade is rotated about the axis and over and in contact with the tubular film, to apply a further perforation line, as the perforation unit, including the axis, moves across the width of the tubular film.
6 . The method of claim 1 , wherein the film path includes a downward path portion onto the mandrel, and the perforation unit is located along the downward path portion.
7 . The method of claim 1 , wherein the perforation unit is coupled to the drive by a belt.
8 . The method of claim 7 , wherein the perforation unit rides along a bearing rail of the machine during movement of the perforation unit.
9 . The method of claim 3 , wherein the perforation unit comprises a cassette in which the perforation blade is mounted for rotation, wherein a portion of the perforation blade protrudes from the cassette and into the side slot.