Tissue paper cutting mechanism having upper knife arm with variable spiral curve angle and upper knife structure therefor

A tissue paper cutting mechanism for cutting a long tape of tissue paper into a plurality of regular length paper pieces, comprising:

• a base;
• a bed knife roller including a roller shaft mounted to the base so that the bed knife roller is rotatable in a predetermined rotating direction about a first longitudinal axis, the bed knife roller having a plurality of straight bed knives provided on a circumferential surface at angularly spaced intervals in parallel with said first longitudinal axis;
• a knife carrier including a carrier shaft mounted to the base at a position in the vicinity of the bed knife roller, the knife carrier being disposed at second longitudinal axis, the second longitudinal being at a horizontal axis skew angle with respect to the axis of the bed knives;
• and
• an upper knife secured to a structural surface of the knife carrier to extend between opposing longitudinal ends thereof, the upper knife extending arcuately in a non-linear spiral contour to define an angle of inclination relative to a tangent of the bed knife roller at a point of contact with one of the bed knives, the angle varying during a cut along the length of the upper knife;
• whereby when the long tape of tissue paper is fed and conveyed between the knife carrier and one of the bed knives roller, a single point shearing contact is formed between the upper knife and the bed knife of the bed knife roller to cut the tissue paper.