Patent Application
20090000216
The field of the invention is pest control.
There are a variety of mechanisms for pest exclusion; however, currently there is a need in the art for economical pest exclusion device that is environmentally friendly and easily adaptable to a variety of environments and locations. Moreover, the current mechanisms for pest control are not very long lasting, lack resiliency, and susceptible to being pulled out by pests.
Rodents get into buildings through existing openings as small as ¼ of an inch or by gnawing and digging their own holes through walls, door frames, foundations or other barriers. Modern integrated pest management practices recommend that rodents be excluded from moving along their typical pathways and limiting their access to structures by sealing those openings with suitable means. The embodiments described herein solve these problems as well as others.
The foregoing and other features and advantages are defined by the appended claims. The following detailed description of exemplary embodiments, read in conjunction with the accompanying drawings is merely illustrative rather than limiting, the scope being defined by the appended claims and equivalents thereof.
The composite for pest control and deterrence comprises an interengaged mixture of metal and nonmetal fibers, wherein the metal fibers include barbed projections and a rough outer surface with irregular shape and the interengaged mixture is formed into a pest deterrence composite.
The foregoing description of the figures is provided for a more complete understanding of the drawings. It should be understood, however, that the embodiments are not limited to the precise arrangements and configurations shown.
The methods, apparatuses, and systems can be understood more readily by reference to the following detailed description of the methods, apparatuses, and systems, and the following description of the Figures.
Generally speaking, in one embodiment, the composite web 10 comprises an interengaged mixture of a plurality of metal fibers and a plurality of nonmetal fibers, as shown in
Metal Fiber
In one embodiment, the plurality of metal fibers 20 is shown in
A suitable lubricant, such as oil, is preferably applied to the metal member as it is being shaved by the blades in sufficient quantity so that the metal fibers retain on their outer surface a carding-effective amount of the oil or lubricant. “Carding-effective amount” of oil or lubricant means that the metal fibers, when blended with the nonmetal fibers, can be carded without substantial breakage or disintegration. The lubricant optionally may be applied after the metal fibers are formed. The commonly assigned U.S. Pat. No. 5,972,814 discloses the process for shaving a metal bar to produce lubricated metal fibers and the use of such lubricated metal fibers. A carding-effective amount of oil generally may be in the range of about 0.3 to 1.0 wt. % oil, more preferably about 0.4 to 0.7 wt. %, based on the total weight of the metal fibers, although lesser or greater amounts may be used depending on the type and average diameter of the metal fibers and the amount and type of nonmetal fibers included in the blended fiber mixture. For example, as the weight percentage of nonmetal fibers relative to the metal fibers is decreased, the quantity of oil or lubricant necessary to provide a carding effective amount may tend to increase. Conversely, as the weight percentage of nonmetal fibers relative to metal fibers increases, the nonmetal fibers may act as a “carrier” for the metal fibers in the carding step, reducing the quantity of oil needed for carding without breakage of the metal fibers. Thus, a carding-effective amount of oil for carding various combinations and amounts of metal and nonmetal fibers can be readily determined on a case-by-case basis. Preferably, the metal fibers are made from stainless steel, as to prevent rusting and corrosion of the composite web. However, the metal fibers 20 can also be made from bronze, carbon steel, copper, metal alloys, and other suitable metals that can be shaved into suitable metal fibers to suit a variety of pest deterring applications. The metal fibers can have an average cross sectional diameter of between about 25 and 125 microns.
The metal fibers 20 are cut into staple lengths using a suitable metal fiber cutting apparatus to give the metal fibers a predetermined length, ranging between about 1 inch to about 12 inches, more preferably less than about 6 inches. In one embodiment, the metal fibers may have a length of about 6 inches prior to carding. In another embodiment, post carding web having metal fibers of approximately 1 to 3 inches long, due to a certain amount of fiber breakage occurs during the carding process. The metal fibers include a relatively high aspect ratio, where “aspect ratio” means ratio of fiber length to fiber diameter. In one embodiment, the aspect ratio may be about 75 to about 85, where the high aspect ratio results in an increased interengagement along the length of the metal fiber. Alternatively, the aspect ratio may be about 25 to about 75 for a lower aspect ratio in smaller composite web examples.
Nonmetal Fibers
In one embodiment, the nonmetal fiber 22 is shown in
The lengths of the nonmetal fibers may be from about 1 inch to about 12 inches, and are more preferably less than about 6 inches in length. In one embodiment, the nonmetal fibers have a length from about 1 to 3 inches. The nonmetal fibers may be cut to size by conventional means. The nonmetal fibers are less brittle than the metal fibers, and are generally unaffected by the carding process. The grade of the nonmetal fibers may range from about 1 denier to about 120 denier. In another embodiment, the nonmetal fibers may range from about 10 to 80 denier, or alternatively from about 18 to 60 denier. In general, the metal fibers will have an average cross-sectional diameter that is from ½ to 2-times the cross-sectional diameter of the nonmetal fibers. Alternatively, the metal fibers and nonmetal fibers will have similar average diameters and lengths. In one embodiment, composite web comprises synthetic polymer fibers, such as polyester or polypropylene fibers, having a grade of about 60 denier and metal fibers having an average cross section of about 60 microns. In another embodiment, the composite web comprises bicomponent fibers having a 12 denier and metal fibers having an average cross section of about 60 microns.
Crimped synthetic fibers having a repeating “V” shape along their length such as that shown in
In another embodiment, the composite web 10 has a ratio of metal fibers to non-metal fibers of between about 10:1 and about 99:10, by weight. In another embodiment of the invention, the composite web 10 comprises about 75 to 95 wt. % metal fibers and about 5 to 25 wt. % nonmetal fibers. Alternatively, the composite web comprises about 85 to 92 wt. % metal fibers and about 8 to 15 wt. % nonmetal fibers.
As will be appreciated by those skilled in the art, metal fibers are several fold denser than nonmetal fibers—that is the specific gravity of metal fibers is substantially greater than the specific gravity of synthetic fibers and other nonmetal fibers. Accordingly, it will be understood that composite web may have relatively similar numbers of metal fibers and nonmetal fibers, even though, on a weight percent basis, the composite web is mostly metal.
It will also be appreciated by the person having ordinary skill in the art that “denier” is a measure of specific weight (or fineness) of a fiber which is arrived at by weighing a predetermined length of the fiber. (One denier equals 0.05 grams per 450 meters). Accordingly, different nonmetal fabrics having the same denier may have different cross-sectional diameters.
Construction of Composite Web
The composite is made by blending a predetermined amount of metal fibers 20 and a predetermined amount of nonmetal fibers 22 to provide a blend of metal and nonmetal fibers; carding the blended fibers to form a fiber web having metal fibers and nonmetal fibers distributed throughout; lapping the fiber web into a multilayered web structure; and needle punching the multilayered web structure to interengaged the fibers in adjacent layers to provide the composite web, as shown in
In the blending step, the metal fibers 20 and nonmetal fibers 22 are blended prior to the carding step to obtain a substantially homogeneous mixture of the fibers, as disclosed in the commonly assigned U.S. Pat. No. 6,502,289. The blending of the staple fibers may be accomplished by various mechanical means. In one embodiment, two or more types of fibers may be mixed in an apparatus that is commonly known as a feedbox or blender and then fed directly into a carding apparatus. In another embodiment, a tandem feedbox arrangement may be used, that is an apparatus comprising two feedboxes in series, with the fibers being fed from the second feedbox directly into a carding apparatus. In another embodiment, the blending step may be performed by a series of apparatuses including a single feedbox, a precard machine to open up both the metal and nonmetal fibers and blend them, and a stock fan blower. Other, more elaborate blending lines may be used in the blending step. Any of these foregoing blending methods are suitable for use in accordance with the embodiments, depending on the degree of homogeneity desired for the composite web.
In one embodiment, a predetermined weight of staple length, shaved stainless steel fibers 20 (60 micron average diameter, 0.6% oil by weight) and staple length polyester fibers 22 (60 denier, 7 crimps per inch) are introduced into a hopper 24 of a feedbox 26 in a ratio of about 91 wt. % metal fibers (including oil) to 9 wt. % nonmetal fibers. As shown in
In
The blend of fibers 20, 22 is fed from second feedbox 56 into a shaker chute, and then into the garnett 58 and is formed into a web 60, as shown in
The multi-layered web structure 68 is then fed through a compression apron 70, as shown in
The composite web may be needlepunched to a low penetration of a needle per square inch (“PPSI”) so that the puncture density will maintain the resiliency of the composite web and compress the metal and nonmetal fibers to a sufficient degree. PPSI is a function of strokes per minute (R), needles per 1 inch width (D) and inches per minute of material traveled (S), where PPSI=(R×D)/S. In one embodiment, the composite web is needlepunched to a penetration of 400 PPSI, with a range of 300-500 needles per square inch. A high penetration of a needle per square inch and a high puncture density decreases the resiliency of the composite web, as it would compress the metal and nonmetal fibers to a greater degree. While pests are prevented form dissembling the composite web due the interengagement of the fibers, radial resiliency of the composite web maintains an obstruction level for pests. Therefore, a lower puncture density can rely more on the heat fusing step below for strength and compressibility to spring back to a thickness, as the nonmetal fibers adhere to other nonmetal fibers and metal fibers. Pests can become entrapped in the interengaged mixture of fibers; alternatively pests are prevented from disassembling the composite web due to the interengagement of the fibers.
The needles 76 and 80 of the needling punching apparatus 72 includes a gauge, a barb, a point type and a blade shape (i.e. pinch blade, star blade, conical, and the like). The gauge of the needles is defined as the number of needles that can be fitted in a square inch area. In one embodiment, the gauge of the needle may be between about 20 to about 40 gauge with a regular barb. The major components of the needle include the crank, the shank, the intermediate blade, the blade, the barbs, and the point. The crank is the 90 degree bend on the top of the needle and seats the needle when inserted into the punch boards 74 and 78. The shank is the thickest part of the needle. The shank is that part of the needle that fits directly in the punch board itself. The intermediate blade is put on fine gauge needles to increase flexibility, which is typically put on 32 gauge needles and finer. The blade is the working part of the needle and is what passes into the multi-layered structure 68 and is where the all barbs are placed. The barbs carry and interlock the metal and nonmetal fibers. The shape and sized of the barbs can dramatically affect the composite web 10. The point is the very tip of the needle. In one embodiment, the felting needles are 32 gauge regular barb needles with a pointed end including three sided needles with 3 barbs per blade.
As the punch boards 74 and 78 move up and down, the blades of the needles 76 and 80 penetrate the multilayered web structure 68, as shown in
The needle punching apparatus 72 includes machine variables of the depth of penetration and puncture density. The travel of the metal and nonmetal fibers through the composite web depends on the depth of penetration of the needles 76 and 80. The maximum penetration is fixed by the needles 76 and 80 of the needle punching apparatus 72 and depends on the length of the three sided shank, the distance between the needle plates, the height of stroke, and the angle of penetration. The greater the depth of penetration, the greater the entanglement of fibers is within the multi-layered structure 68, because more barbs are employed per penetration. In one embodiment, the penetration depth may be between about ½ of an inch to about 1 inch.
The puncture density is the number of punches on the surface of the feed in the web. The puncture density is a complex factor and depends on the density of needles in the needle board (Nb), the rate of material feed (V), the frequency of punching (F), the effective width of the needle board (W), and the number of runs. The puncture density per run Edpass=[n*F]/[V*W], where, n=number of needles within the punch boards, F=frequency of punching, V=rate of material feed, and W=effective width of the needle board. The puncture density in the needled fabric EdNV depends on the number of runs Npass; EdNV=Edpass*Npass. The frequency of punching is formulated in the PPSI formula. The thickness, basis weight, bulking density and air permeability provide information about compactness of composite web and are influenced by a number of factors. If the basis weight of the composite web and puncture density and depth are increased, the composite web density increases and air permeability is reduced (when finer needles and longer, finer and more tightly crimped fibers are used). Preferably, the basis weight of the composite web, puncture density, and penetration depth are maintained to result in a resiliency greater than steel or copper wool. In one embodiment, the needles per inch width are 96 needles and the resiliency of the composite web is about 2 to 5 times greater than steel or copper wool.
As far as the strength of the composite web, the situation is similar to that for compactness, namely that finer needles, finer and longer fibers, greater composite web basis weight and greater puncture depth and density, result in increased strength and resiliency of the composite web. However, once a certain critical puncture depth or density has been reached, the rise in strength and resiliency may be reversed. If the depth of the barb is decreased or the distance between the barbs is increased, the dimensional stability is improved during needling, and the web density, resiliency, and maximum tensile strength in relation to basis weight can be raised. The resiliency of the composite web is determined from the penetrations per square inch (“PPSI”), the needle penetration depth, and the type of needles that are being used. The frequency of needle punching is part of the equation for figuring out the PPSI, as indicated above. Alternative punching apparatuses include different needle densities and different needle patterns, which affect the tightness or resiliency of the composite web.
In one embodiment, a heat-fusing step fuses at least a portion of the nonmetal and metal fibers at their intersections to increase the resiliency, strength, and durability of the composite web. As shown in
With reference to
Other methods of heating and melting the synthetic fibers include compressed hot air, direct radiant heating such as with an oven, or laminating the nonmetal fibers with adhesives. “Laminating” means securing nonmetal fibers together or to metal fibers by any adhering process, such as heat application, adhesives, pressure, mechanical bonding, or any combinations thereof. Laminating forms a bond between two surfaces; this may be a thermal bond, a chemical bond, or a mechanical bond. Adhesives may be any suitable material that is compatible with the nonmetal fiber and the metal fiber. Laminating the nonmetal fiber and the metal fiber increases the stability, strength, and deterring properties of the composite web 10.
The density of the metal and nonmetal fibers 100 to about 3000 g/m2. By needle punching, lapping, and laminating the composite web 10, the required density for the desired pest exclusion operation can be obtained. For large pests, a higher density of 2500 g/m2 to result in an increased resiliency. For smaller pests, a lower density of 500 g/m2 may be desired to squeeze the composite web into smaller holes or passageways. Alternatively, the composite web may include a density gradient, whereby one end of the composite web includes an increased density of 1000 to about 2000 g/m2, and another end of the composite web includes a lower density of about 500 to about 1000 g/m2. Such a gradient density allows for the composite web to be inserted in a small hole or passageway with the lower density end, while the higher density end is able to deter larger pests with an increased resiliency.
The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how the articles, devices, systems, and/or methods claimed herein are made and evaluated, and are intended to be purely exemplary and are not intended to limit the scope of articles, systems, and/or methods. Efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperature, etc.), but some errors and deviations should be accounted for.
In one embodiment, the composite web 400 includes stainless steel metal fibers 410 and 18 denier polyester fibers 420, as shown in
Additionally, the composite web can be molded into three dimensional shapes, such as cones or bullet shaped plugs 300, as shown in
If desired, the composite may optionally include various additives, such as insect repellents and animal repellents, which may enhance the performance of the composite as a deterrent agent. Additionally, the composite web 10 may molded and adhered to various structures by any desirable fashion. For example, the composite web 10 may be adhered to an opening by plug fitting the composite web 10 with sufficient resiliency that the composite web 10 provides a pest barrier. Alternatively, the composite web 10 may be tacked, stapled, glued, or laminated to a crack, crevice, or gap.
It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the scope or spirit of the embodiments described herein. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the embodiments disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the embodiments being indicated by the following claims.
The present application claims priority to U.S. Provisional Application Ser. No. 60/944,322, filed Jun. 15, 2007.
| Number | Date | Country | |
|---|---|---|---|
| 60944322 | Jun 2007 | US |
