Method and apparatus for removing wrapping from rolls

A method for removing a wrapping from a roll of material, said roll having a center axis, a cylindrical roll body, a first roll body end portion with a first roll end gable, a second roll body end portion with a second roll end gable, and a roll envelope surface between the first roll body end portion and the second roll body end portion, said wrapping having an envelope portion covering said roll envelope surface, a first envelope end portion covering said first roll end gable and a second envelope end portion covering said second roll end gable, the method comprising the steps of:

• moving a single cutting means into abutment against the wrapping at said first roll body end portion such that the wrapping is punctured;
• rotating the roll about the center axis of the roll over a rotational angle (φ) less than 360 degrees, at the same time as the wrapping is cut by the cutting means at said first roll body end portion, the cutting means inclining and forming an end portion cutting angle (α) in relation to a plane perpendicular to said center axis of said roll during cutting of the first envelope end portion or the second envelope end portion, wherein the first envelope end portion of the wrapping k not completely cut off by the cutting means when the cutting means is positioned at the end portion cutting angle (α);
• moving the cutting means axially along the center axis of the roll towards said second roll body end portion and at the same time rotating the roll about said center axis such that the wrapping on the envelope surface of the roll k cut in a helical manner, wherein the wrapping on the envelope surface of the roll is cut with the cutting means, the cutting means further inclining and forming an envelope surface cutting angle (β) in relation to the plane during cutting of the envelope portion, wherein said envelope surface cutting angle (β) is larger than said end portion cutting angle (α);
• and
• rotating the roll further about the center axis of the roll over the rotational angle (φ) less than 360 degrees, at the same time as the wrapping is cut by the cutting means at said second roll body end portion, the cutting means forming said end portion cutting angle (α),
• such that the wrapping is cut off the roll in one continuous piece.