Fiber densification knife

A cutting device for effecting a cut in a board-like fibrous material and densifying an area adjacent to the cut, includes a main body portion and a blade portion extending from the main body portion. The blade portion includes a cutting edge having first and second angled surfaces extending divergingly therefrom. A densifying member extends outwardly from at least one of the first and second angled surfaces. The densifying member compresses an area of the material adjacent to the cut as the blade is pressed into the material and densifies the adjacent area. The compression surface may be configured non-planar with an upper surface of the board-like material to selectively, variably densify the area adjacent to the cut.

FIELD OF THE INVENTION 
This invention relates to a knife for cutting fibrous material. More 
particularly, the invention relates to a knife for cutting fibrous 
material such as paperboard and the like and densifying the material in an 
area adjacent to the cut. 
BACKGROUND OF THE INVENTION 
Fiber based products, such as paperboard and the like, are in widespread 
use in the construction and manufacture of packaging materials. Such 
materials are used, in part, because of their ease of forming, e.g., 
creasing and folding, and relatively low cost. Paperboard materials will 
be recognized by most consumers as one of the most commonly used packaging 
materials for many different types of products. 
Fiber based materials have also come into use in the construction and 
manufacture of liquid packaging materials. Again, this is due, in part, to 
the lower cost of fiber based materials, vis-a-vis polymeric, i.e., 
plastic container materials. Fiber based containers are also significantly 
easier to manufacture compared to containers molded from plastic 
materials. 
Advances in fiber based, e.g., paperboard, technology enable the use of 
paperboard for liquid food packaging materials. Paperboard based materials 
are now recognized as a preferred container material for many types of 
liquid foods. For example, juice, milk and the like, are commonly packaged 
in paperboard based materials. Non-food items such as laundry detergent, 
laundry softeners and the like are also commonly found packaged in 
paperboard packaging. 
It has been observed that paperboard packaging can be problematic for 
liquids products. One known problem is that the liquid product can be 
absorbed into the packaging material by a wicking phenomena which occurs 
at the edges of the material which come into contact with the liquid. 
Liquid wicks, or is transported from the edges of the packaging material 
into the paperboard body of the container material. Wicking can compromise 
the structural integrity of the package, and can cause contamination of 
the food product packaged in the container. 
Wicking can be reduced or eliminated by sufficiently increasing the density 
of the packaging material. This is typically effected by increasing the 
density and thus the weight of the entirety of the material package. While 
this is a somewhat effective solution, the material and manufacturing 
costs increase commensurately with increased material weight. 
Accordingly, there continues to be a need for a cost effective densified 
packaging material which effectively reduces or eliminates wicking of the 
liquid product into the packaging material. Preferably, such a packaging 
material has selectively densified areas to maintain the low cost 
advantages and other benefits of paperboard packaging. 
SUMMARY OF THE INVENTION 
A cutting device for effecting a cut in a board-like fibrous material and 
densifying an area adjacent to the cut, includes a main body portion and a 
blade portion extending from the main body portion. The blade portion has 
a cutting edge having first and second angled surfaces extending 
divergingly therefrom. The cutting device includes a densifying member 
which extends outwardly from at least one of the first and second angled 
surfaces. 
The cutting device is positioned with the blade portion in contact with, 
and impressed into, the fibrous material. The blade effects a crush cut of 
the material, while the densifying member compresses an area of the 
material adjacent to the cut and densifies the adjacent area. 
The cutting device may be configured to selectively, variably densify the 
area adjacent to the cut by having a compression surface which is 
non-planar with an upper surface of the board-like material. 
An alternate embodiment of the cutting device includes first and second 
densifying members extending outwardly from a respective one of the 
angled, diverging surfaces. Each of the densifying members defines a 
compression surface adapted to compress an area adjacent to its respective 
side of the cut and densifying the respective areas. The densifying 
members and compression surfaces can be alike to effect consistent 
densification of the areas on the sides adjacent to the cut. 
Alternatively, either or both of the densifying members can be configured 
differently from one another to effect different densification properties 
to achieve specific, desired results. 
In a present embodiment, the densifying member extends from the angled 
surface at about a midpoint of the surface. 
Other features and advantages of the present invention will be apparent 
from the following detailed description, the accompanying drawings, and 
the appended claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
While the present invention is susceptible of embodiment in various forms, 
there is shown in the drawings and will hereinafter be described presently 
preferred embodiments with the understanding that the present disclosure 
is to be considered an exemplification of the invention and is not 
intended to limit the invention to the specific embodiments illustrated. 
With reference now to the figures, and in particular to FIGS. 1 and 2, 
there is shown an embodiment of the cutting device 10 of the present 
invention. The cutting device 10 includes generally a main body portion 12 
and a blade portion 14. The blade portion 14 has a cutting edge 16 and 
includes first and second adjacent, angled surfaces 18, 20. The surfaces 
18, 20 extend upwardly, diverging from the cutting edge 16. 
The cutting device 10 is configured for use with most types of fibrous 
materials. The device is particularly useful for cutting fibrous material, 
such as paperboard, formed as a blank or sheet, which is used for 
manufacturing packing for liquid products. As will be recognized by those 
skilled in the art, the use of fibrous material, such as paperboard, for 
liquid product packaging has been significantly increasing. Examples of 
such uses of paperboard for liquid packaging include food products such as 
juices, milk and the like. 
The packaging material can be formed of, for example, a plurality of 
layers, or a laminate of various materials, one or more of which layers is 
a fibrous material. One typical laminate L, as illustrated in FIG. 1, 
includes an inner layer of thermoplastic material I, such as low density 
polyethylene (LDPE), a barrier material B such as metal foil, a paperboard 
layer P, and an outer layer O of thermoplastic material, such as LDPE. 
Laminated container structures are disclosed in Andersson et al., U.S. 
Pat. No. 4,989,736, which patent is incorporated herein by reference. 
It will also be recognized by those skilled in the art, that particularly 
in the food packaging industry, it is of utmost importance to provide 
sterile, uncontaminated packaging materials and packaging designs which 
further the objective of reducing or eliminating the potential for 
contamination of the food product. To that end, it has been observed that 
the wicking can occur at the edges of fibrous packaging material which is 
exposed to the liquid product stored in the package. The wicking phenomena 
draws liquid from the exposed edges into the body of the material. This 
can be problematic in that liquid in the body of the packaging material 
can compromise the structural integrity of the package, and may result in 
contamination of the food product. This can be particularly significant in 
the food packaging industry. 
It has also been observed that the wicking phenomena is inversely 
proportional to the density of the packaging material. That is, as the 
density of the packaging material increases, the amount of liquid 
absorbed, and/or the rate of absorption decreases. Thus, it would be 
desirable to provide packaging material which is relatively dense at the 
edges which come into contact with the liquid product, which edges are 
susceptible to wicking, in order to reduce the amount of liquid which the 
packaging material absorbs. 
The present cutting device 10 overcomes the problems associated with edge 
wicking by providing a packaging material that is selectively densified at 
cut edges which may be exposed to the liquid material in the package. 
Essentially, the present cutting device 10 is configured to densify 
predetermined portions of the packaging material to reduce wicking and 
thus absorption. 
As best seen in FIG. 2, the blade portion 14 of the cutting device 10 
extends from the main body portion 12. In a typical container 
manufacturing process, the paperboard material, illustrated in FIG. 1 as a 
laminate L, is crush cut at its edges by the cutting edge 16 of the blade 
14. The angled surfaces 18, 20 facilitate cutting the material L. A 
densifying member 22 extends outwardly from one of the angled surfaces 18 
in a step-like manner. The densifying member 22 has a compression surface 
24 which is configured to engage and compress the packaging material L, as 
the cutting device 10 and blade 14 are pressed into the material L. 
Essentially, the densifying member 22 produces an anvil-like effect which 
compresses and densifies the material in an area A under the compression 
surface 24 adjacent to the cut location C. The densifying member 22 has a 
riser surface 26 which extends from the compression surface 24 to the main 
body portion 12. 
In a typical configuration, the cutting edge 16 is a flat surface having a 
width W of about 2 to about 4 thousands of an inch (2 to 4 mils). The 
cutting edge 16 is in spaced relation to the main body portion 12. The 
force of the blade 12 into the material L effects a crush cut of the 
material L by the cutting edge 16. The densifying member 22 is configured 
to densify the material in an area A under the member 22, adjacent to the 
cut C. Typical, the packaging material L is a flat, planar material having 
a consistent thickness t. In a current embodiment, the compression surface 
24 is flat, and is configured to be generally parallel to the plane P of 
the material. Thus, a substantially consistent densification of the 
material L in the area A adjacent to the cut C occurs. It will be 
recognized that the compression surface 24' can be configured other than 
parallel to the material plane P such that the material L in area A can be 
selectively, variably densified to produce a desired effect (FIG. 3). 
Referring to FIGS. 1 and 2, the angled surfaces 18, 20 extend upwardly from 
the cutting edge 16 at a predetermined angle. In a current embodiment, 
each of the surfaces forms an angle .alpha. with a centerline of the blade 
portion, as illustrated by the arrow at 28, of about 30.degree.. In one 
embodiment, the riser surface 26' is parallel to the centerline 28, i.e., 
perpendicular to the plane P of the material L (FIG. 3). Alternately, as 
illustrated in FIGS. 1 and 2, the riser surface 26 can be formed at an 
angle .beta. relative to the blade centerline 28. 
In a current embodiment, the densifying member 22 extends outward from the 
angled surface 18, at about a midpoint of the surface 18 between the 
cutting edge 16 and the main body portion 12. That is, the surface 18 has 
a length S, and the member 22 extends from the surface 18 at about a 
distance of S/2 from the edge 16. Alternately, the member 22 can extend 
from the surface 18 from other than the midpoint to achieve a specific, 
desired densification characteristic and result. 
An alternate embodiment 110 of the cutting device is illustrated in FIGS. 
4-5. Similar to the embodiment 10 illustrated in FIGS. 1-3, the alternate 
embodiment 110 includes a main body 112 portion having a blade portion 114 
extending therefrom. The blade 114 includes a cutting edge 116 having 
first and second angled surfaces 118, 120 extending from the edge 116. The 
alternate embodiment 110 includes first and second densifying members 122, 
124 extending respectively from the first and second angled surfaces 118, 
120. 
The densifying members 122, 124 may be configured similar to the member 22, 
and may be similar to one another. Alternately, the first and second 
members 122, 124 may be formed differently from one another in order to 
achieve specific desired results at the opposing areas A.sub.1, A.sub.2 
adjacent to the cut. 
Similar to the embodiment 10, the densifying members 122, 124 of the 
cutting device 110 can extend from their respective surface 118, 120 from 
about the midpoint of the surface between the cutting edge 116 and the 
main body portion 112. Alternately, to achieve specific, desired 
densification characteristics, the members 122, 124 can extend from their 
respective surfaces 118, 120 from other than the midpoints. As shown in 
FIG. 6, the cutting device 110' has a blade portion 114' with a densifying 
member 122' extending from a surface 118' at a point lower than the 
midpoint of a cutting edge 116' and a main body portion 112'. The blade 
portion 114' also has a densifying member 124' extending from a surface 
120' at a point higher than the midpoint of the cutting edge 116' and the 
main body 112'. Additionally, similar to FIG. 3, the densifying member 
122' has a non-parallel compression surface 123'. Areas A1' and A2' are 
compressed differently due to the different positioning of densifying 
members 122' and 124'. 
Notwithstanding the linear appearance of the cutting device embodiments 10, 
110, illustrated, it will be recognized by those skilled in the art that 
both embodiments 10, 110 of the device can be configured in circular, as 
well as other desired arrangements. 
From the foregoing it will be observed that numerous modifications and 
variations can be effectuated without departing from the true spirit and 
scope of the novel concepts of the present invention. It is to be 
understood that no limitation with respect to the specific embodiments 
illustrated is intended or should be inferred. The disclosure is intended 
to cover by the appended claims all such modifications as fall within the 
scope of the claims.