1. Field of the Invention
This invention is related to weaving of multilayer products woven from columns of warp fibers controlled by heddle columns. In particular, the ratio of the number of warp columns to the number of heddle columns is a fractional number.
2. Description of the Related Art
The use of reinforced composite materials to produce structural components is now widespread, particularly in applications where their sought desirable characteristics are being light in weight, strong, tough, thermally resistant, self-supporting and adaptable to being formed and shaped. Such components are used, for example, in aeronautical, aerospace, satellite, recreational use (as in racing boats and autos), and other applications.
Typically such components consist of reinforcement materials embedded in matrix materials. The reinforcement component may be made from materials such as glass, carbon, ceramic, aramid, polyethylene, and/or other materials which exhibit desired physical, thermal, chemical and/or other properties, chief among which is great strength against stress failure. Through the use of such reinforcement materials, which ultimately become a constituent element of the completed component, the desired characteristics of the reinforcement materials, such as very high strength, are imparted to the completed composite component. The constituent reinforcement materials may, for example, be woven into multilayer preform structures.
Weaving has been employed for many centuries to create woven structures. Woven structures are formed by interlacing threads, yarns, or fibers that fall into two categories: (i) the “warp threads”, yarns, or fibers that are parallel to the selvedges, or edges, (sometimes called machine direction or MD) and which are interlaced or “woven,” with (ii) a perpendicular series of “weft threads”, yarns, or fibers (sometimes called cross-machine direction or CD). Typically, the warp and weft yarns or fibers are interlaced to make a woven structure on a weaving loom. The simplest weave pattern consists of an alternating pattern where each weft thread, yarn, or fiber passes successively above and below a warp thread or fiber. More complex structures are woven in three dimensions (3D weaving) such that additional yarns bind the warp and weft yarns in multilayer structures.
Customarily, weaving looms employ three primary motions within the weaving process: i) shedding, (ii) picking, and (iii) beating-up. Shedding involves forming a triangular opening between groups of warp fibers for the passage of weft fibers by a shuttle, for example. Picking involves passing the weft fiber through the shed. And beating-up involves using a comb-like reed to pack the weft fibers as close as desired to each other in a repeating weave pattern.
Commonly, in Jacquard weaving, the weaving component that is used to separate warp fibers, and form the shed, or triangular opening or space through which the weft fiber can pass, is called a heddle. Control of the vertical position of the heddles controls the formation of the shed. The shed opening may be formed by lifting one set of warp fibers relative to another set. Alternatively, one set of fibers may be lifted from a neutral position and the remaining fibers lowered from the same neutral position. In some cases, alternating warp fibers are lifted with respect to adjacent fibers. Or a number of consecutive fibers are lifted together, or are not raised, to form a desired pattern with the weft fibers in the woven structure.
Usually, heddles are elongated structures made from metal, wire, twisted wire, polymeric braid, pressed sheet metal, polyester, or string with an appropriately sized eye, or opening, through which a warp fiber is passed through. The top and bottom of the heddles have structures that allow them to be attached, connected, or mounted to a component called the heddle harness or heddle column. By and large, warp fibers extend from a warp beam, or warp creel, on one end of the loom, pass through a heddle, and attach to another beam, or fabric column, at the other end of the loom. After the weft fibers are passed through the shed formed by the warp fibers, a reed is used to beat up, or tighten the weft and warp fibers into the desired pattern and density.
One characteristic of woven structures is the number of warp fibers per inch of woven-material width. In weaving terminology, the number of warp fibers per width-wise inch is known as dents per inch or “dpi.” For example, a woven structure with 12 warp fibers per width-wise inch would be referred to as a 12 dpi material.
Normally, the weaving loom has suitable heddle-column geometry that was chosen for the woven structure being produced. By way of exemplary illustration, if the woven structure being produced is to have 12 dpi, the heddle column may have 12 heddles per inch. Because each warp yarn passes through one heddle, the dpi of the woven material determines the number of heddles per inch width, or heddle spacing, on the heddle column.
Typically, woven structures to be used for preforms are multilayer 3D structures. That is, when viewed from a horizontal plane, multiple layers of warp ends can be found. For example, in a 32-layer woven structure, there would be 32 warp ends through the thickness of the material when viewed from a horizontal cut. These warp fibers are usually arranged in columns such that a 32-layer woven structure would have 32 warp fibers per warp column.
When weaving a multilayer structure for a preform, the weaving apparatus geometry may be selected such that the heddle-column spacing can be multiplied by a whole number to achieve the desired warp-column spacing. For example, if a 32-layer preform with 12 warp fibers per width-wise inch, or dpi, were desired, the weaving apparatus could have a heddle column with 32 heddles where the heddle spacing would be 12 heddles per inch. As such, fibers on one warp column would be laced through heddles on one heddle column. Alternatively, a heddle column with 64 heddles where the heddle spacing would be 6 heddles per inch may be used. With 64 heddles per column, fibers on two warp columns would be laced through heddles on a heddle column. In some circumstances of multilayer woven structures with high warp fiber counts, configuring the weaving apparatus where one heddle column would weave one warp column can have too much warp and weft fiber congestion to weave efficiently. When configuring the weaving apparatus where one heddle column would weave two warp columns, the depth of the heddles is large so that a very small shed opening may be formed, resulting in poor warp control and difficulties in weaving.
This disclosure can provide for a weaving apparatus with a warp column and heddle column configuration that allows for efficient weaving of multilayer products by, for example, reducing warp and weft fiber congestion, increasing better warp control, and having an adequate shed opening for weaving.
The terms “fibers”, “threads”, and “yarns” are interchangeably used in this disclosure. “Fibers”, “threads”, and “yarns” can refer to, for example, monofilaments, multifilament yarns, twisted yarns, multifilament tows, textured yarns, braided tows, coated yarns, bicomponent monofilament yarns, as well as yarns made from stretch broken fibers. “Fibers” and “yarns” can also refer to glass, carbon, ceramic, aramid, polyethylene, and/or other materials which exhibit desired physical, thermal, chemical and/or other properties, chief among which is great strength against stress failure.
This disclosure can provide for an apparatus for weaving a multilayer product having one or more warp columns for placement of warp fibers and one or more heddle columns for the placement of heddles for lacing warp fibers. This disclosure can provide for a numerical ratio of warp columns and heddle columns that is a fractional number and where a portion of the warp fibers are laceable through the heddles on one or more of the heddle columns based on that fractional number.
This disclosure can provide for an apparatus for weaving a multilayer product having a numerical ratio of warp columns and heddle columns that is a fractional number where the number of warp columns is a high warp column count of at least 3 and the number of heddle columns is less than the high warp column count. And this disclosure can provide for where the number of warp fibers on each of the warp columns equals the number of layers in the multilayer product such that the number of layers in the multilayer product multiplied by the fractional number and further multiplied by the number of heddle columns is at least equal to the number of layers in the multilayer product multiplied by the high warp column count.
This disclosure can provide for a fractional number between 0.1 and 10.5, and would be understood by one of ordinary skill in the art more commonly as between 1.5-4.5. This disclosure can provide for a multilayer product having two or more layers.
This disclosure can provide a method for weaving a multilayer product with the steps of having a weaving apparatus with one or more warp columns and one or more heddle columns where the numerical ratio of the warp columns to heddle columns is a fractional number. And where there is step of segmenting adjacent warp fibers and lacing the segmented warp fibers through the heddles on the heddle columns based on the fractional number. This disclosure can provide for controlling warp fibers laced through heddles on heddle columns with the heddles.
For a better understanding of this disclosure, its operating advantages and specific objects attained by its uses, reference is made to the accompanying descriptive matter in non-limiting, exemplary embodiments of the invention are illustrated.
Terms “comprising” and “comprises” in this disclosure can mean “including” and “includes” or can have the meaning commonly given to the term “comprising” or “comprises” in U.S. Patent Law. Terms “consisting essentially of” or “consists essentially of” if used in the claims have the meaning ascribed to them in U.S. Patent Law.
The accompanying drawings, which are included to provide a further understanding of the disclosure, are incorporated in and constitute a part of this specification. The drawings presented illustrate different, nonlimiting embodiments of the invention and together with the description serve to explain the principles of this disclosure. In the drawings:
Exemplary embodiments of weaving apparatus with warp columns counts and heddle columns counts are disclosed that facilitate weaving multilayer preforms where the ratio of warp columns to heddle columns is a fractional number and where a portion of the warp fibers are laceable through the heddles on one or more of the heddle columns based on the fractional number, allowing for better and more adequate shed space and efficient weaving than in prior art techniques.
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Moreover, this disclosure can provide a method for lacing adjacent warp fibers on a warp column through adjacent heddles on a heddle column. For example,
Further, this disclosure can provide for a number of heddles on each heddle column that can be determined by multiplying the fraction as between the number of warp columns to heddle columns with the number of layers in the multilayer preform. For example,
Further, this disclosure can provide for a number of warp fibers on each warp column equal to the number of layers in the multilayer preform. For example,
This disclosure can provide for a total number of heddles that equals or approximately equals the total number of warp fibers. For example,
This disclosure can also provide for a weaving apparatus with a ratio of warp columns to heddle columns that is a fraction and where the number of warp fibers on each warp column equals the number of layers in the multilayer product such that when the number of warp fibers on each warp column is multiplied by that fraction and then further multiplied by the total number of heddle columns, it is at least equal to the number of layers in the multilayer preform multiplied by the number of warp columns. For example,
Turning to
The number of heddles on each heddle column in
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The number of heddles on each heddle column in
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The number of heddles on each heddle column in
This disclosure can provide lacing 606 all warp fibers on a first warp column 603 through adjacent heddles on a top portion of the first heddle column 601, lacing 607 a top half of the warp fibers on a second warp column 604 through adjacent heddles on the bottom portion of the first heddle column 601, lacing 608 a bottom half of the warp fibers on the second warp column 604 through adjacent heddles on the top portion of a second heddle column 602, and lacing 609 all warp fibers on a third warp column 605 through adjacent heddles on the bottom portion of the second heddle column 602.
This disclosure can provide for an adequate shed space for efficiently weaving weft fibers for a multilayered preform using an apparatus with multiple warp columns and multiple heddle columns having a numerical ratio that is a fractional number. For example, having a high warp column count, as would be understood by a person of skill in the art of at least 3 warp columns, fewer heddle columns, and the numerical ratio between them as a fractional number, eliminates small shed openings and poor warp control that otherwise typically occurs making it difficult to weave a multilayer product.
While embodiments of the invention have been described and variations set forth above, these embodiments and variations are illustrative and the invention is not to be considered limited in scope to these embodiments and variations. For example, the number of layers in the multilayer product can vary. As another non-limiting example, the number of warp columns to heddle columns can vary, e.g. a 1.5 ratio can encompass three warp columns to two heddle columns and twelve warp columns to eight heddle columns, and so on and so forth. Accordingly, various other embodiments and modifications and improvements not described herein may be within the scope of the present disclosure, as defined by the following claims.
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Entry |
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International Search Report and Written Opinion issued by the EPO, acting at the ISA, for international application PCT/US2017/016191 mailed May 10, 2017. |