Knife having beam elements
A knife including a cutting edge, a fixed edge, and a plurality of beam elements connecting the cutting edge to the fixed edge, each of the beam elements having a beam element extent oriented between about 20 degrees and about 80 degrees off of the cutting edge, each beam element separated from adjacent beam elements by a reduced stiffness zone, each reduced stiffness zone having a reduced stiffness zone extent oriented from about 20 degrees to about 80 degrees off of the cutting edge. The knife can be employed in a process and an apparatus for cutting a web.
1. A process of cutting a web comprising steps of:
providing a web;
providing a knife mounted on a press, wherein said knife comprises:
a cutting edge;
a fixed edge; and
a plurality of beam elements connecting said cutting edge to said fixed edge, each of said beam elements having a beam element extent oriented between 20 degrees and 80 degrees off of said cutting edge, each said beam element separated from adjacent beam elements by a reduced stiffness zone, each reduced stiffness zone having a reduced stiffness zone extent oriented from 20 degrees to 80 degrees off of said cutting edge, wherein each of said beam elements has a beam element width orthogonal to said beam element extent and a beam element length in line with said beam element extent, wherein each of said beam elements has a ratio of beam element length to beam element width from 2 to 40;
providing an anvil supporting said web as said web passes between said anvil and said press; and
cutting said web with said knife as said web passes between said press and said anvil.
2. The process according to claim 1 , wherein said press is a rotary press rotating in a machine direction and said knife is mounted in a cross direction of said rotary press orthogonal to said machine direction; and
wherein said anvil is a rotary anvil rotating counter to said rotary press.
3. The process of claim 2 , wherein said beam elements are nearer to said cutting edge than to said fixed edge.
4. The process of claim 3 , wherein said reduced stiffness zones are slots.
5. The process of claim 2 , wherein said knife is mounted approximately perpendicular to said rotary press.
6. The process of claim 1 , wherein each of said reduced stiffness zones has a reduced stiffness zone width orthogonal to said reduced stiffness zone extent and a reduced stiffness zone length in line with said reduced stiffness zone extent, wherein each of said reduced stiffness zones has a ratio of reduced stiffness zone length to reduced stiffness zone width from 2 to 40.
7. An apparatus for cutting a web comprising:
a rotary press having a machine direction and a cross direction orthogonal to said machine direction;
a rotary anvil; and
a knife comprising:
a cutting edge;
a fixed edge; and
a plurality of beam elements connecting said cutting edge to said fixed edge, each of said beam elements having a beam element extent oriented from 20 degrees to 80 degrees off of said cutting edge, each said beam element separated from adjacent beam elements by a reduced stiffness zone, each reduced stiffness zone having a reduced stiffness zone extent oriented from 20 degrees to 80 degrees off of said cutting edge,
wherein each of said beam elements has a beam element width orthogonal to said beam element extent and a beam element length in line with said beam element extent, wherein each of said beam elements has a ratio of beam element length to beam element width from 2 to 40, and
wherein said knife is mounted to said rotary press with said cutting edge oriented in said cross direction.
8. The apparatus of claim 7 , wherein said beam elements are nearer to said cutting edge than to said fixed edge.
9. The apparatus of claim 8 , wherein said reduced stiffness zones are slots.
10. The apparatus of claim 8 , wherein said knife is mounted approximately perpendicular to said rotary press.
11. The apparatus of claim 8 , wherein each of said reduced stiffness zones has a reduced stiffness zone width orthogonal to said reduced stiffness zone extent and a reduced stiffness zone length in line with said reduced stiffness zone extent, wherein each of said reduced stiffness zones has a ratio of reduced stiffness zone length to reduced stiffness zone width from 2 to 40.