FIBER DENSIFICATION KNIFE

Abstract: A cutting device (10, 110, 110') for effecting a cut in a board-like fibrous material and densifying an area adjacent to the cut, includes a main body portion (12, 112, 112') and a blade portion (14, 114, 114') extending from the main body portion (12, 112, 112'). The blade portion (14, 114, 114') includes a cutting edge (16, 116, 116') having first and second angled surfaces (18, 20 or 118, 120 or 118', 120') extending divergingly therefrom. A densifying member (22, 122) extends outwardly from at least one of the first and second angled surfaces (18, 20 or 118, 120 or 118', 120'). The densifying member (22, 122) compresses an area of the material adjacent to the cut as the blade (14, 114, 114') is pressed into the material and densifies the adjacent area. The compression surface (24) may be configured non-planar with an upper surface of the board-like material to selectively, variably densify the area adjacent to the cut.

Description: FIBER DENSIFICATION KNIFE Technical Field 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 Art 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 liquid 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. Disclosure 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 density 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. It is a priamry object of the present invention to provide a cutting device having at least one densifying member. It is an additional object of the present invention to provide a cutting device having two densifying members. It is an additional object of the present invention to proivde a cutting device having a non-parallel densifying member relative to the material. Brief Description of the Drawings FIG. 1 is a side elevational view of a cutting device embodying the principles of the present invention, the device being illustrated pressed into an exemplary laminated paperboard sheet; FIG. 2 is a side elevational view of the cutting device of FIG. 1, without the paperboard sheet; FIG. 3 is a side elevational view of the cutting device illustrating a non- planar compression surface and a riser surface parallel to the centerline of the cutting device blade portion; FIG. 4 is a side elevational view of an alternate embodiment of the cutting device, the device being illustrated impressed into a paperboard sheet; FIG. 5 is a side elevational view of the alternate embodiment without the paperboard sheet; and FIG. 6 is a side elevational view of an alternate embodiment of the cutting device with offset densifying members, the device being impressed into a paperboard sheet. Modes for Carrying Out the Invention and Industrial Applicability As shown in FIGS. 1 and 2, 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. The packaging material can be formed of, for example, a plurality of layers, or a laminate of various materials, one of 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. The 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 density 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.f The densifying member 22 is configured to density 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 with a centerline of the blade portion, as illustrated by the arrow at 28, of about 30°. 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). Alternatively, as illustrated in FIGS. 1 and 2, the riser surface 26 can be formed an angle β 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. Alternatively, 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 Ai, A 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 Al ' 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.

Claims: Claims 1. A cutting and compression knife for effecting a cut in a board-like fibrous material and for densifying an area adjacent to the cut, comprising: a main body portion; a cutting edge in spaced relation to the main body portion; a densifying member extending from the knife intermediate the main body portion and the cutting edge, the densifying member having a compression surface configured to engage and compress the area adjacent to the cut as the knife is urged and impressed into the board-like material. 2. A cutting device for effecting a cut in a board-like fibrous material and densifying an area adjacent to the cut, the cutting device comprising: a main body portion; a blade portion extending from the main body portion, the blade portion having a cutting edge and having first and second angled surfaces extending divergingly from the cutting edge; and a densifying member extending outwardly from one and only one of the first and second angled surfaces, the angled surface opposite the densifying member extending divergingly from the cutting edge to the main body portion, the_densifying member having a compression surface configured to contact the board-like material and density the adjacent area. 3. A cutting and compression knife for effecting a cut in a board-like fibrous material and for densifying an area adjacent to the cut, comprising] a main body portion] a cutting edge in spaced relation to the main body portion first and second densifying members extending from respective opposing sides of the knife intermediate the main body portion and the cutting edge, the densifying members each having a compression surface configured to engage and compress the area adjacent to the cut as the knife is urged and impressed into the board-like material and as the densifying members contact and compress the area therebeneath, respectively, each densifying member extending from respective opposing side of the knife at different distances from the cutting edge so as to effect different densification characteristics thereby, at least one of the compression surfaces configured other than parallel to an upper surface of the board-like material. 4. A cutting device (10) for effecting a cut in a board-like fibrous material and densifying an area adjacent to the cut, the cutting device (10) having a main body portion (12) and a cutting portion (14) with a cutting edge (16), the cutting device (10) characterized in that the cutting portion (14) has first and second angled surfaces (18, 20) extending divergingly from the cutting edge (16) with a densifying member (22) extending outwardly from one and only one of the first and second angled surfaces (18,20), the densifying member (22) having a compression surface (24) configured to engage and compress the area adjacent to the cut as the cutting device is urged and impressed into the board-like material. 5. A cutting device (110 or 110') for effecting a cut in a board-like fibrous material and densifying an area adjacent to the cut, the cutting device (110 or 110') having a main body portion (112 or 112') and a cutting portion (114 or 114') with a cutting edge (116 or 116'), the cutting device (110 or 110') characterized in that the cutting portion (114 or 114') has first and second angled surfaces (118,120 or 118', 120') extending divergingly from the cutting edge (116 or 116') with densifying members (122, 124 or 122', 124') extending outwardly from each of first and second angled surfaces (118,120 or 118', 120'), the densifying members (122, 124 or 122', 124') each having a compression surface configured to engage and compress the areas adjacent to the cut as the cutting device is urged and impressed into the board-like material. 6. The cutting device in accordance with any of the previous claims wherein at least one angled surface has a length extedning between the cutting edge and main body portion, and wherein the densifying member extends outwardly from the surface at about a midpoint of the length. 7. The cutting device in accordance with any of the previous claims wherein at least one of the compressions surfaces of at least one of the densifying members is non-parallel relative to the upper surface of the board-like material. 8. The cutting device in accordance with claims 3 and 5 wherein the compression surface of both densifying members is non-parallel relative to the upper surface of the board-like material.

Inventors: PUHL MICHAEL, PUHL, MICHAEL
Applicants: PUHL MICHAEL, TETRA LAVAL HOLDINGS & FINANCE, PUHL, MICHAEL, TETRA LAVAL HOLDINGS & FINANCE, S.A.
Application year: 1998
Main classification: B26B27
IPC codes: B26B27, B26D7, B29C65, B29C67, B31B1, B31F7