Apparatus for sealing a wrapper film sleeve

An apparatus for sealing a wrapper sleeve transversely to an advancing direction thereof, comprising

• (a) a first sealing shoe supported for rotation about a first axis;
• said first sealing shoe including a first peripheral surface having
• (1) a generatrix being parallel to and at a maximum distance from, said first axis;
• (2) a length measured in a circumferential direction of said first peripheral surface;
• and
• (3) a radius of curvature being smaller at any point of said length than said maximum distance;
• (b) a second sealing shoe supported for rotation about a second axis oriented parallel to said first axis;
• said second sealing shoe including a second peripheral surface;
• said first and second peripheral surfaces together defining a line of contact with one another with the wrapper sleeve interposed therebetween;
• (c) means for rotating said first and second sealing shoes in synchronism for causing said first and second peripheral surfaces to roll on one another effecting sealing of the wrapper sleeve as the wrapper sleeve moves in the advancing direction;
• and
• (d) a device for displacing said first axis relative to said second axis in a direction transverse to said advancing direction of the wrapper sleeve for effecting displacement of said line of contact in said advancing direction as said first and second sealing shoes rotate.