Non-symmetrical heavy duty knife apparatus and cutting method

A method of cutting a sanitary napkin from a layered absorbent material web, comprising:

• a) providing a linear first cutting member having a first end;
• b) providing a linear second cutting member joined to said first end of said first cutting member;
• c) providing a third cutting member having a linear section and an arcuate section joined to said first end of said first cutting member and further joined to said linear second cutting member;
• d) providing a non-symmetrical configuration formed by said linear second cutting member and said third cutting member cooperating with said first cutting member and having an outside edge and an arcuately shaped centerline;
• e) providing a cutting edge on said first, said second, and said third cutting members having a cutting edge knife thickness in the range of greater than 0.003 inches to about 0.005 inches;
• and
• f) providing a cutting edge surface area in the range of up to about 70 of the total surface area of a rectangle drawn over said non-symmetrical configuration and formed by a first rectangle line between each of two rectangle corner points located on said outside edges of said second and said third cutting members, respectively, at a location where said respective arcuate section is joined to said linear section, a second rectangle side line and a third rectangle side line perpendicular to said first rectangle side line at each of said two rectangle corner points and extending a distance through a centerline positioned where said second cutting member joins said third cutting member, and a fourth rectangle side line parallel to said first rectangle side line at a distance from said center line equal to the distance between said first rectangle side line and said center line, said fourth rectangle side line intersecting said second and third rectangle side lines to form said rectangle within said first, second, third, and fourth rectangle side lines.

A knife, comprising:

• a) a first cutting member having a first end;
• b) a second cutting member joined to said first end of said first cutting member, said second cutting member having an interior edge;
• and
• c) a third cutting member joined to said first end of said first cutting member, said third cutting member having an interior edge joining said second cutting member having an interior edge to form a circular arc between said second and third cutting members, said second and said third cutting members being arranged relative to one another to form an angle there between of from between about 30° to about 150°, said second cutting member having a linear section and said third cutting member having an arcuate section which cooperate with said first cutting member to form a non-symmetrical configuration, said third cutting member having a linear section integrally joined to said arcuate section and said first, said second, and said third cutting members having a same knife thickness, said knife thickness ranging from between greater than 0.003 inches to about 0.005 inches;
• and
• d) wherein each of said second and third cutting members has an outside edge and when a rectangle is drawn about the point of intersection of said first, second and third cutting members, the area of cutting surface of said knife is up to about 70% of the total surface area of said rectangle, said rectangle being formed by drawing a first line through two points, each of said points being located on one of said outside edges of said second and third cutting members, respectively, at a location where said arcuate section is joined to said linear section, a second line and a third line are then drawn perpendicularly to said first line at locations where said first line crosses said outside edges of said second and third cutting members, respectively, a fourth line is then drawn parallel to said first line such that it passes through a point where the centerline of said second cutting member joins the centerline of said third cutting member, and a fifth line is drawn parallel to said fourth line and at a distance from said fourth line which is equal to the distance between said first and fourth lines, said fifth line being drawn on the same side of the first line as is the fourth line, and said fifth line said second and third rectangle side lines to form said rectangle within said first, second, third, and fourth rectangle side lines.