Composite Paddles and Methods for Forming same

TECHNICAL FIELD

The present teachings pertain generally to composite materials and structures for forming sporting equipment and more specifically to fibrous composites for forming pickleball paddles.

BACKGROUND

Most pickleball paddles and other racquets on the market today are constructed from carbon fiber or fiberglass. While the performance of these materials is desirable, the materials are neither sustainable nor recyclable and involve a significant carbon footprint. However, efforts to avoid use of these materials often results in a paddle that suffers from performance deficiencies. Simply replacing carbon fiber or fiberglass with natural, sustainable materials results in a paddle that may not function appropriately and/or may be uncomfortable for use.

The International Federation of Pickleball (IFP) and the USA Pickleball Association (USAPA) set the rules and regulations for pickleball paddles. The guidelines for allowable pickleball paddles include restrictions on surface roughness, reflection, size, and appearance.

It would therefore be desirable to develop a paddle that utilized natural and sustainable materials in unique configurations and manufacturing techniques so that carbon fiber and fiberglass can be eliminated or minimized while still allowing for a paddle that performs well and provides significant comfort to the user. It would be further desirable for a paddle that utilizes natural and sustainable materials while still meeting the requirements set forth by the International Federation of Pickleball (IFP) and the USA Pickleball Association (USAPA).

SUMMARY OF THE INVENTION

The teachings herein are directed to a paddle comprising a striking portion defining a central axis, a handle portion, and a tapered portion contiguous with both the handle portion and the striking portion; a sandwich structure comprising a core layer and a first skin coupled with the core layer, the first skin comprising a first fabric layer and a second fabric layer coupled with the first fabric layer.

The paddle may include a substrate interposed between the core layer and the first skin, the substrate configured to facilitate coupling of the core layer and the first skin. The core layer may be a honeycomb structure including one or more cells. The substrate may be a non-woven polymeric fabric, the non-woven polymeric fabric configured to prevent a resin from seeping into the one or more cells of the honeycomb structure.

The first fabric layer may be a hemp fabric of between 100 and 170 gsm. The first fabric layer may include a weave pattern that is positioned between −10 degrees and 10 degrees relative to the central axis. The second fabric layer may be a twill flax fabric of between 200 and 300 gsm. The second fabric layer may include a weave pattern positioned at between −10 degrees and 10 degrees relative to the central axis. The first fabric layer may be a bidirectionally woven fabric. The second fabric layer may be a bidirectionally woven fabric positioned at between −5 degrees and 5 degrees, relative to the first fabric layer.

The core may comprise a synthetic material. The core may comprise a natural material. The core may comprise an impregnated fiber material. The core may comprise a prepreg laminate material. One or more of the first skin and the second skin may comprise at least six distinct layers stacked in a helical pattern. The core may comprise a dry to the touch material. The core may comprise a tacky material. The core may comprise at least two distinct geometries. The core may comprise a first central geometry that is surrounded by a second perimeter geometry that is different from the first central geometry. The core may comprise a first central geometry that is substantially honeycomb shaped. The core may comprise a first central geometry that is surrounded by a second perimeter geometry, and the second perimeter geometry is substantially gyroid shaped.

An additive manufacturing process may form the core. The handle portion may comprise a material that forms the second perimeter geometry. The core may comprise a spiral shape. The core may comprise a spiral shape and the material for forming the spiral shape increases in thickness as the spiral travels to an outer edge of the paddle. The increase in thickness of the material for forming the spiral is from about 20% to about 40% from a beginning point of the spiral to an end point of the spiral. The core may comprise a plurality of branches formed in accordance with Murray's law. The core may comprise a cardboard grid including an optional resin coating. The core may comprise a woven composite material. The woven composite may be impregnated with a resin.

The first skin may be cured separately from the core layer and may be coupled with the core layer after a curing process. The first skin may be cured with the core layer such that the first skin and the core layer are coupled via a cure process. The first skin and a second skin may be formed of the same materials. The first skin and a second skin may be formed of different materials.

A nonwoven substrate may be located between the first skin and the core layer. A nonwoven substrate may be located between a second skin and the core layer. The nonwoven substrate may comprise a polymeric material. The nonwoven substrate may comprise a polypropylene or polyester material. The nonwoven substrate may be coupled to the core layer by a hot melt adhesive, and adhesive film, an adhesive resin, or some combination thereof.

The first fabric layer, the second fabric layer or both may be fabrics that are impregnated with a resin selected from epoxy resin, polyester resin, vinyl ester resin, phenolic resin, bio resin, thermoplastic resin, or any combination thereof. The first fabric layer, the second fabric layer, or both may be formed of fibers pre-impregnated with resin. The first fabric layer, the second fabric layer, or both may comprise a fiber mat, a cloth, or some combination thereof. The first fabric layer, the second fabric layer, or both may comprise a plain weave hemp having a density of at least about 120 g/cm², but less than about 150 g/cm². The first fabric layer, the second fabric layer, or both may include a unidirectional weave. The first fabric layer, the second fabric layer, or both may include a bidirectional weave having threads extending in a first x-direction and having threads extending in a first y-direction, the first fabric layer, the second fabric layer, or both include a +45/−45-degree weave, where the first x-direction is substantially perpendicular to the first y-direction. The first fabric layer, the second fabric layer, or both may include a 90/0-degree weave.

The teachings herein are further directed to a paddle comprising a first composite skin comprising a first fabric layer having a bidirectional weave and formed of a flax fiber and a second fabric layer having a bidirectional weave and formed of a hemp fiber; a second composite skin comprising a third fabric layer having a bidirectional weave and formed of a flax fiber and a fourth fabric layer having a bidirectional weave and formed of a hemp fiber; and a honeycomb core structure interposed between the first composite skin and the second composite skin.

The first fabric layer may be outward facing such that the second fabric layer is interposed between the first fabric layer and the honeycomb core structure. The third fabric layer may be outward facing such that the fourth fabric layer is interposed between third fabric layer and the core structure.

The paddle may include a striking portion and a handle portion, the striking portion and the handle portion defining a central axis such that the striking portion and the handle are symmetrical about the central axis, the striking portion comprising a leading edge positioned opposite to the handle portion and perpendicular to the central axis.

The first fabric layer may be positioned such that at least one of the first x-direction and the first y-direction is positioned within 10 degrees of parallel with the central axis. The third fabric layer may be positioned such that at least one of the third x-direction and the y-direction is positioned within 10 degrees of parallel with the central axis. The second fabric layer may be positioned such that at least one of the second x-direction and the second y-direction is positioned within 10 degrees of parallel with the central axis The fourth fabric layer may be positioned such that at least one of the fourth x-direction and the fourth y-direction is positioned within 10 degrees of parallel with the central axis.

The paddle may include an edge guard positioned about a perimeter of the striking portion. The paddle may include a second edge positioned parallel with the central axis. The paddle may include a third edge positioned parallel with the central axis.

All of the first fabric layer, the second fabric layer, the third fabric layer, and the fourth fabric layer may be prepreg sheets. The first fabric layer, the second fabric layer, the third fabric layer, the fourth fabric layer or any combination thereof may be fabrics that are impregnated with a resin selected from epoxy resin, polyester resin, vinyl ester resin, phenolic resin, bio resin, thermoplastic resin, or any combination thereof. The first fabric layer, the second fabric layer, the third fabric layer, the fourth fabric layer or any combination thereof are formed of fibers pre-impregnated with resin. The first fabric layer, the second fabric layer, the third fabric layer, the fourth fabric layer or any combination thereof may comprise a fiber mat, a cloth, or some combination thereof. The first fabric layer, the second fabric layer, the third fabric layer, the fourth fabric layer or any combination thereof may comprise a plain weave hemp having a density of at least about 120 g/cm², but less than about 150 g/cm². The first fabric layer, the second fabric layer, the third fabric layer, the fourth fabric layer or any combination thereof may include a unidirectional weave. The first fabric layer, the second fabric layer, the third fabric layer, the fourth fabric layer or any combination thereof may include a bidirectional weave having threads extending in a first x-direction and having threads extending in a first y-direction. The first fabric layer, the second fabric layer, the third fabric layer, the fourth fabric layer or any combination thereof may include a +45/−45-degree weave, where the first x-direction is substantially perpendicular to the first y-direction, the first fabric layer, the second fabric layer, the third fabric layer, the fourth fabric layer or any combination thereof may include a 90/0-degree weave.

The teachings herein also envision a composite structure for forming a paddle comprising at least two layers of about 200 gsm twill woven natural fiber fabric, a resin impregnated in the fabric, and a honeycomb core adhered to the at least two layers via the resin.

The teachings herein are further directed to a composite structure for forming a paddle comprising at least one first layer of bi-axial natural fiber fabric having a fiber orientation of +45° and −45° or +/−30° or +/−60°, at least one second layer of unidirectional natural fiber fabric having a fiber orientation of 0° or 90°, and a resin material located in direct contact with one or both of the first or second layer.

The teachings herein are also directed to a method for forming a laminate for forming a paddle comprising laying up at least three layers of woven hemp mixed with about 30% to about 50% resin content by weight and compressing the three layers using a compression molding machine to form a laminate.

The teachings herein further envision a composite structure for forming a paddle comprising at least one layer of woven natural fiber fabrics with a fiber orientation of 0° and 90° and a thermoplastic resin selected from polypropylene, polylactic acid, or combinations thereof impregnated in the at least one layer of woven natural fiber fabrics

The composite structure may include a core which may be a honeycomb core located adjacent the first layer, the second layer, or both.

The teachings herein are further directed to a sandwich panel comprising a first composite skin comprising a first fabric layer having flax fibers, the first fabric layer having an areal weight of between 200 and 300 grams per square meter, inclusive, and a second fabric layer having hemp fibers, the second fabric having an areal weight of between 100 and 200 grams per square meter, inclusive; a second composite skin comprising a third fabric layer having flax fibers, the third fabric layer having an areal weight of between 200 and 300 grams per square meter, inclusive and a fourth fabric layer having hemp fibers, the fourth fabric having an areal weight of between 100 and 200 grams per square meter, inclusive. The sandwich panel may include a core structure interposed between and coupled to both the first composite skin and the second composite skin

The first fabric layer may include a bidirectional weave having first warp threads and first weft threads. The second fabric layer may include a bidirectional weave having second warp threads and second weft threads. The first fabric layer may be coupled to the second fabric layer such the one of the first warp threads and the first weft threads is within five degrees of parallel with the second warp threads.

The first composite skin may be coupled to a first side of the panel such that the second fabric layer is interposed between the first fabric layer and the honeycomb panel. The second composite skin may be coupled to a second side of the core structure such that the fourth fabric layer is interposed between third fabric layer and the honeycomb core structure, the second side of the core structure being opposite the first side of the core structure.

The paddle may include a striking portion and a handle portion, the striking portion and the handle portion defining a central axis such that the striking portion and the handle are symmetrical about the central axis. The first fabric layer may be formed of a bidirectional weave and includes first warp threads and first weft threads. The third fabric layer may be formed of a bidirectional weave and includes third warp threads and third weft threads. The first fabric layer may be positioned such that at least one of the first warp threads and the first weft threads is positioned within 10 degrees of parallel with the central axis. The third fabric layer may be positioned such that at least one of the third warp threads and the third weft threads is positioned within 10 degrees of parallel with the central axis.

The first fabric layer may be formed of a unidirectional weave and includes first threads. The third fabric layer may be formed of a unidirectional weave and includes third threads. The first fabric layer may be positioned such that the first threads are positioned within five degrees of parallel with the central axis. The third fabric layer may be positioned such that the third threads are positioned within five degrees of parallel with the central axis.

The second fabric layer may be positioned such that at least one of the second x-direction and the second y-direction is positioned within 10 degrees of parallel with the central axis. The fourth fabric layer may be positioned such that at least one of the fourth x-direction and the fourth y-direction is positioned within 10 degrees of parallel with the central axis.

All of the first fabric layer, the second fabric layer, the third fabric layer, and the fourth fabric layer may be prepreg sheets.

The first fabric layer may be a synthetic fiber material and the second fabric layer may be a natural fiber material. The synthetic material may be a recycled carbon fiber, a recycled fiberglass, basalt, recycled ultra-high molecular weight polyethylene (UHMWPE), or some combination thereof. The natural fiber material may be selected from flax or hemp or combinations thereof. The paddle may include a third fabric layer wherein the first fabric layer may be a synthetic fiber, the second fiber layer may be a natural fiber, and the third fiber layer may be a synthetic fiber. The synthetic material may be selected from carbon fiber, basalt, or combinations thereof, and the natural fiber may be selected from flax, hemp, or combinations thereof. Vibrations may be reduced during use of the paddle as compared to a paddle without the natural fiber layer.

The core layer may comprise a plurality of walls for forming cavities having differing shapes, sizes and cross sections. The core layer may comprise a plurality of cavities having differing shapes, sizes and cross sections so that the walls and cavities mimic the structure of bird bones. The core layer may comprise a cavity that receives a plurality of equally sized substantially circular components for supporting the cavity.

The teachings herein describe advantageous materials and methods related to the manufacture of paddles and more specifically to materials and material arrangements and Systems for forming paddle cores.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1. is a perspective view of an exemplary embodiment of a paddle in accordance with the teachings herein.

FIG. 2 is a front view of the paddle of FIG. 1.

FIG. 3 is a bottom cross-sectional view of the paddle along the line AA of FIG. 2.

FIG. 4 is a detailed cut-away view of the front of an exemplary embodiment of a paddle in accordance with the present teachings.

FIG. 5 is a detailed cut-away view of the front of an exemplary embodiment of a paddle in accordance with the present teachings.

FIG. 6 is a detailed cut-away view of the front of an exemplary embodiment of a paddle in accordance with the present teachings.

FIG. 7 is a detailed exploded view of the paddle along line AA of FIG. 2.

FIG. 8 is a front view of an exemplary embodiment of a paddle in accordance with the present teachings.

FIG. 9 is a detailed cut-away view of the front of the paddle of FIG. 8.

FIG. 10 is a schematic of an exemplary layered laminate material in accordance with the present teachings.

FIG. 11 shows the layered laminate of FIG. 10 during formation of a prepreg using the laminate.

FIG. 12 is a perspective view of two paddles having cores of differing geometries alongside an exemplary paddle having a core that includes both differing geometries.

FIG. 13A-13D shows the formation of an exemplary paddle having a spiral core.

FIGS. 14A-14D shows variations on exemplary paddle cores having a “tree-like” format.

FIG. 15 shows exemplary paddle core structures imitating a “bone-like” arrangement.

FIG. 16 is a cross sectional view of exemplary sandwich panel core arrangements.

FIG. 17 is a perspective view of an exemplary grid core for a paddle.

FIG. 18 is a cross sectional view of an exemplary woven material for a paddle core.

FIG. 19 is a cross sectional view of exemplary woven materials for a paddle core.

FIG. 20 is an exemplary recycling flow chart for use of recycled paddle core materials.

DETAILED DESCRIPTION

The present teachings meet one or more of the above needs by the improved composite structures and methods described herein. The explanations and illustrations presented herein are intended to acquaint others skilled in the art with the teachings, its principles, and its practical application. Those skilled in the art may adapt and apply the teachings in its numerous forms, as may be best suited to the requirements of a particular use. Accordingly, the specific embodiments of the present teachings as set forth are not intended as being exhaustive or limiting of the teachings. The scope of the teachings should, therefore, be determined not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. The disclosures of all articles and references, including patent applications and publications, are incorporated by reference for all purposes. Other combinations are also possible as will be gleaned from the following claims, which are also hereby incorporated by reference into this written description.

This application is related to and claims the benefit of the filing date of U.S. Provisional Application Ser. No. 63/172,752, filed Apr. 9, 2021, the contents of that application being hereby incorporated by reference herein for all purposes.

A pickleball paddle (e.g., racket, racquet, pickleball paddle, ping pong paddle, etc.) includes a striking portion formed of a sandwich panel having a core structure interposed between two composite laminate layers. The core structure may be formed of a lightweight material, such as foam, a polymeric core, aluminum honeycomb, and polymeric honeycomb. The core structure of a pickleball paddle must be rigid enough such that the pickleball paddle meets the requirements of the International Federation of Pickleball (IFP) and the USA Pickleball Association (USAPA).

The teachings herein are directed to materials and methods relating for forming a paddle. The paddles described herein may include a core layer and one or more composite skins. The composite skins may be formed of a variety of different natural, synthetic and recycled materials and may preferably be formed of combinations of these materials. The composite skins may be formed using multiple layers (e.g., two layers, three layers, four layers, eight layers, or even more layers). Each of the layers may comprise the same materials. Each of the layers may comprise different materials. The layers may be selected to alternate two or more materials. Each layer in itself may comprise more than one type of material (e.g., more than one type of fiber, or fibers with coatings thereon). The layers may be coated with a resin, impregnated with a resin, or each fiber of a layer may be coated with a resin. The layers may be formed of woven or nonwoven materials. The layers may be formed of fibers having a relatively low glass transition temperature. The fibers and/or the resin may be formed from thermoplastic materials that can be repaired, reformed and/or recycled upon exposure to heat. The resin and/or fibers may be formed of a thermoset or thermosettable material. The resin and/or fibers may include a foam material or a material that is adapted to foam upon exposure to a stimulus.

The paddles may utilize resins, adhesives, films, tapes or other similar joining means to form the resulting combination of core layer and composite skins. The process for forming the paddles described herein may include one or more heating, curing, pressing or compressing steps. The composite skins may be formed and cured in a separate step and may then be assembled with a core layer, which may also include a curing step. Curing may occur at ambient temperatures. Curing may occur upon exposure to heat, UV light, microwave, induction heat, or another stimulus.

The method of formation may include forming a first and second composite skin by layering one or more layers onto a platen press to form an uncured first and second composite skin assembly. The first composite skin, a core structure, and the second composite skin may be layered to form an uncured sandwich panel assembly. In some embodiments, the first composite skin, the core structure, and the second composite skin are layered so that the first composite skin and second composite skin each lie in direct planar contact with the core structure (core layer). A first fabric layer and second fabric layer may form the first composite skin. A fourth fabric layer, and a third fabric layer may form the second composite skin.

The uncured composite skins (including first and second composite skins) may be enclosed within a vacuum bag. The uncured composite skins may be debulked within the vacuum bag. The uncured and debulked composite skins may then be placed in an autoclave while the uncured composite skins are still positioned within the vacuum bag. The uncured composite skins are cured in the autoclave and then assembled with the core and heated in a platen press.

The paddles described herein may be treated and/or formed to develop a desirable texture (e.g., roughness) on the exterior surfaces of the paddle. The texture of the paddle is important for spinning the ball and also for allowing graphics and/or paint to adhere to the surface of the paddle. The allowable limits for roughness set forth by the USAPA shall be no greater than 30 micrometers (μm) on the Rz reading (average maximum height, peak to valley), and no greater than 40 micrometers (μm) on the Rt reading (maximum height, peak to valley). As one non-limiting example, a lightly woven, textured peel ply or release film (usually with weight of 20-90 gsm, or even 25-55 gsm) is placed on the A-side (e.g., the exterior side) of the composite skin and cured with the skin. The peel ply may then be removed, leaving behind a light texture that is slightly less than or equal to the IFP/USAPA regulations of 30 Rz and 40 Rt.

It may also be possible to utilize a custom cut/engineered flat plate surface using fine CNC milling or lasers to create a mold of exact the IFP/USAPA regulations of 30Rz and 40 Rt average texture reading. The surface would have a sharp high friction texture like a triangle wave and not a rolling texture like a sine wave. The skins may be cured on this plate mold and when removed from the mold so that the texture would be imparted onto the exterior (“A”) surface of the skin.

It is further possible that a heated textured roller may be used to impart texture to the skin surface after it has cured where the texture on the roller is similar to the flat plate surface proposed above and presses the specific surface texture into the mold. The surface may have a sharp texture like a triangle wave and not a rolling texture like a sine wave. This shard texture allows for more friction between the ball and striking surface compared to a rounded sine wave like texture.

Referring now to FIG. 1, a perspective view of a paddle 100 (e.g., pickleball paddle, racket, etc.) is shown, according to an example embodiment. The paddle 100 includes a sandwich panel 102 (e.g., paddle core), an edge guard 104, grip tape 106, and an endcap 108. The sandwich panel 102 is formed in the shape of the paddle 100 and includes a striking portion 110, a handle portion 112, and a tapered portion 114 extending between and contiguous with both the striking portion 110 and the handle portion 112. In some embodiments, the sandwich panel 102 is formed in a non-paddle shape and is later cut out to have the shape shown in FIG. 1. The sandwich panel 102 (FIG. 3) is formed of a core structure 118 interposed between a first composite skin 120 and a second composite skin 122. The composite skins 120, 122 are coupled with (e.g., coupled to, adhered to, cured with, etc.) the core structure 118, such as with an adhesive or resin through an autoclaving process. In some embodiments, the core structure 118 is cured with the composite skins 120, 122. In some embodiments, the composite skins 120, 122 are formed separately from the core structure 118 and are later coupled to the core structure 118, such as with an adhesive or resin.

The sandwich panel 102 provides an improved feel to the user of the paddle 100 without sacrificing rigidity and while still meeting the standards sets by the IFP. The sandwich panel 102 also provides an improved aesthetic to the paddle 100 when compared to other paddles currently available for sale. The natural aesthetic provided by flax, twill, hemp, and similar materials is often desirable by users of pickleball paddles. And the use of organic materials in a panel that meets the requirements of the IFP and the USAPA is unique to the industry.

Referring now to FIG. 2, a front view of the paddle 100 is shown. The paddle 100 is defined by a central axis 125 extending along a longitudinal dimension of the paddle 100 and extending through the handle portion 112. In some embodiments, the paddle 100 is symmetrical about the central axis 125. The paddle 100 further includes a first edge 128 (e.g., leading edge) that extends along a first end 130 of the sandwich panel 102. The first end 130 is positioned opposite to a second end 132 of the striking portion 110. The first edge 128 is bisected (e.g., substantially bisected) by the central axis 125 and extends perpendicular to (e.g., substantially perpendicular to) the central axis 125.

The paddle 100 further includes a second edge 134 and a third edge 136, the third edge 136 being opposite to the second edge 134. Both of the second edge 134 and the third edge 136 extend parallel to the central axis 125 and extend perpendicularly to the first edge 128. The first edge 128 is contiguous with both the second edge 134 and the third edge 136. In some embodiments, the first edge 128 and the second edge 134 meet at a first rounded corner 138. In some embodiments, the first edge 128 and the third edge 136 meet at a second rounded corner 140. The first rounded corner 138 and the second rounded corner 140 are opposite to the handle portion 112.

Referring now to FIG. 3, a cross-section of the paddle 100 is shown along the line AA of FIG. 2. The sandwich panel 102 is formed of a core structure 118 interposed between two composite skins, shown as a first composite skin 120 and a second composite skin 122. In some embodiments, the first composite skin 120 and the second composite skin 122 are substantially similar (e.g., express similar material properties, such as stiffness and tensile strength). In some embodiments, the first composite skin 120 and the second composite skin 122 are different and express different material properties.

The first composite skin 120 and the second composite skin 122 are coupled to the core structure 118 such that the core structure 118 is interposed between the first composite skin 120 and the second composite skin 122. In some embodiments, the first composite skin 120 is cured separately from the core structure 118 and is coupled with the core structure 118 after the first composite skin 120 is cured. In some embodiments, the first composite skin 120 is cured with the core structure 118 such that the first composite skin 120 and the core structure 118 are cured together.

To improve the adhesion of the first composite skin 120 and the second composite skin 122 to the core structure 118, a substrate 124 may be positioned between the composite skins 120, 122 and the core structure 118. In some embodiments, the substrate 124 is a non-woven fabric, such as a non-woven fabric formed from polypropylene, polyester, and similar polymeric materials. The substrate 124 may be coupled (e.g., cured) directly to the core structure 118, such as by hot melt, an adhesive film, or a resin.

The core structure 118 may be formed of paper, synthetic paper, metal, composites, a polymeric material, or the like. In some embodiments, the core structure 118 includes a plurality of cells that extend through (e.g., perforate) the core structure 118. For example, the core structure 118 may be a honeycomb core. In some embodiments, such as when the core structure 118 is a honeycomb core, the core structure 118 may include the substrate 124 that extends over the core structure 118 prevent resin from seeping into the cells of the core structure 118.

The first composite skin 120 is a laminate structure and includes a plurality of fabric layers cured together with a resin. In other words, the first composite skin 120 includes layers of fiber-reinforced resin (e.g., matrix resin in a cured and consolidated composite form). The first composite skin 120 may include any number of fabric layers layered in various orientations relative to one another. Each fabric layer is defined by a material (e.g., flax, hemp, Kevlar, carbon, wood, etc.), a directionality (e.g., biaxial, bidirectional, triaxial, uniaxial, unidirectional, etc.), a weave (e.g., twill, plain, satin, etc.), and a density (measured in grams per cubic centimeter (g/cm³). As used herein, when two fabrics are “in line” or “aligned,” then at least one of the warp and/or weft threads of the first fabric is substantially parallel to at least one of the warp and/or weft threads of the second fabric. This applies to uniaxial, biaxial, and triaxial weaves. This further applies to increasingly unique weaves, such as 0/60 weaves (e.g., 0/120 weaves).

The first composite skin 120 includes a first fabric layer 142 and a second fabric layer 144 coupled with (e.g., cured with) the first fabric layer 142. The first fabric layer 142 may be a biaxial fabric. In some embodiments, the first fabric layer 142 includes a twill weave. In some embodiments, the first fabric layer 142 is formed of an organic material, such as flax or hemp. In some embodiments, the first fabric layer 142 is a plain weave hemp having a density of approximately 132 grams per square centimeter (g/cm²).

In some embodiments, the first fabric layer 142 includes a bidirectional weave having threads extending in a first x-direction 170 and having threads extending in a first y-direction 172. In some embodiments, the first fabric layer 142 includes a +45/−45-degree weave, where the first x-direction is perpendicular to (e.g., substantially perpendicular to) the first y-direction. In some embodiments, the first fabric layer 142 includes a 90/0-degree weave. In some embodiments, the first fabric layer 142 is a twill weave fabric. The twill weave may be a plain weave, a 2×2 weave, and the like. In some embodiments, the first fabric layer 142 is formed of an organic material, such as hemp, flax, wood, and the like. As used herein, “organic material” refers to materials related to or derived from living matter. Organic material does not include carbon fiber, fiberglass, aramid, and similar materials. In some embodiments, the first fabric layer 142 includes flax fibers in a twill weave pattern. In some embodiments, the first fabric layer 142 is formed from hemp fibers in a twill weave. The first fabric layer 142 may have a density between 200-300 grams per square meter (gsm). In some embodiments, the first fabric layer 142 has a density of between 225-275 gsm. In some embodiments, the first fabric layer 142 has a density of between 240-260 gsm.

The second fabric layer 144 includes a bidirectional weave having threads extending in a second x-direction 174 and having threads extending in a second y-direction 176. In some embodiments, the second fabric layer 144 includes a 2×2 twill weave. In some embodiments, the second fabric layer 144 is formed of an organic material, such as flax or hemp. In some embodiments, the second fabric layer is a 2×2 twill weave flax fabric having a density of approximately 245 g/cm². In some embodiments, the warp and weft threads (thread thicknesses, etc.) are of similar (e.g., the same but for manufacturing tolerances) thicknesses

Referring now to FIG. 5, the first fabric layer 142 is positioned at an angle α relative to the second fabric layer 144. In some embodiments, the first x-direction 170 is aligned with at least one of the second x-direction 174 and the second y-direction 176. In other words, the angle α is zero and the first fabric layer 142 is aligned with the second fabric layer 144 (FIG. 5). In some embodiments, such as shown in FIG. 6, the first fabric layer 142 is positioned within +/−10 rotational degrees of being aligned with the second fabric layer 144. In other words, the first x-direction 170 is positioned within 10 rotational degrees of at least one of the second x-direction 174 and the second y-direction 176. In some embodiments, the first fabric layer 142 is positioned at 45-rotational degrees relative to the second fabric layer 144 (FIG. 7). In other words, the first x-direction 170 is positioned at approximately 45 rotational degrees of both the second x-direction 174 and the second y-direction 176. In some embodiments, the first fabric layer 142 is positioned at between 55-35 rotational degrees of the second fabric layer 144.

When the first composite skin 120 is coupled to the core structure 118, the first fabric layer 142 is interposed between the second composite skin 122 and the core structure 118 such that the second composite skin 122 is outwardly facing. In some embodiments, the second fabric layer 144 is positioned such that the second fabric layer 144 is aligned with the central axis 125, as shown in FIG. 2. In other words, when the first composite skin 120 is coupled with the core structure 118, the second fabric layer 142 is positioned such that at least one of the second x-direction 174 and the second y-direction is substantially parallel to the central axis 125. In some embodiments, the second fabric layer 144 is positioned between −10-10 rotational degrees of the central axis 125 when the first composite skin 120 is coupled with the core structure 118. In some embodiments, the second fabric layer 144 is positioned at approximately 45-rotational degrees relative to the central axis 125.

Referring now to FIG. 7, an exploded view of the sandwich panel 102 is shown. In some embodiments, the first fabric layer 142 and the second fabric layer 144 are “dry” fabrics that are impregnated with a resin (e.g., epoxy resin, polyester resin, vinyl ester resin, phenolic resin, bio resin, thermoplastic resins (polypropylene, PLA, polycarbonate), etc.). In some embodiments, at least one of or both of the first fabric layer 142 and the second fabric layer 144 are prepreg sheets. At used herein, the term “prepreg” refers to fibers pre-impregnated with resin, such as a combination of a fibrous substrate (such as a mat, fiber, or cloth material) with resin impregnated on and into the substrate.

Positioned between the first composite skin 120 and the substrate 124 may be a first adhesive film 180. The first adhesive film 180 may be supported by a scrim. Interposed between the first fabric layer 142 and the second fabric layer 144 is a second adhesive film 182. The second adhesive film 182 may include a scrim. Positioned on the second fabric layer 144 opposite to the second adhesive film 182 is a third adhesive film 184. The third adhesive film 184 is unsupported (e.g., does not include a scrim). The third adhesive film 184 is outwardly facing when the sandwich panel 102 is cured. During a curing process, a peel-ply 186, such as frosted glass or frosted aluminum, may be used to provide a texture 190 to a striking surface of the sandwich panel 102. The texture 190 may be in compliance with the requirements of the IFP and the USAPA. Specifically, the average RT texture reading, taken in 6 directions, may be less than or equal to 40 microns and the average RZ texture reading, taken in 6 directions, is less than or equal to 30 microns.

Referring now to FIG. 8, a paddle 200 is shown, according to another example embodiment. The paddle 200 is similar to the paddle 100. Accordingly, like numbering is used to denote like parts between the paddle 100 and the paddle 200. A difference between the paddle 100 and the paddle 200 is that the paddle 200 includes a fabric layer having a unidirectional weave.

The paddle 200 includes the first composite skin 120 including a second fabric layer 244 that includes a unidirectional weave and is formed of flax fibers. When the first composite skin 120 is coupled to the core structure 118, the second fabric layer 244 is aligned with the central axis 125. The unidirectional fibers of the second fabric layer 244 may be flax fibers that provide a desirable wooden or natural look to the user of the paddle 200. In some embodiments, the second fabric layer 244 is pre-impregnated with a resin before assembling. For example, the second fabric layer 244 may be P-UD 3.2, supplied by LINGROVER. In some embodiments, the second fabric layer 244 has a density of between 50-150 gsm. In some embodiments, the second fabric layer 244 has a density of between 75-125 gsm. In some embodiments, the second fabric layer 244 has a density of between 100-120 gsm.

Referring now to FIG. 9, a cut-away view of the paddle 200 is shown. The second fabric layer 244 is aligned with the first fabric layer 142.

A variety of core materials, core geometries, and core formats are shown as examples in FIGS. 10-19. FIG. 10 depicts a layered helical laminate structure 302 including a plurality of layers 300a-30os. These layers can be stacked and impregnated with a resin to form a prepreg 304 as shown for example in FIG. 11.

As an additional embodiment, FIG. 12 shows a first paddle design 306 using a core 308 formed of an additive manufacturing gyroid infill 310. A second core type 312 is shown having a honeycomb configuration 314. By combining the first design 306 and the second design 312, a third core configuration 316 is shown including a honeycomb inner core 318 and a gyroid outer core 320.

The core may be formed to have specific shapes found in nature (“biomimicry”). As one example, FIGS. 13A-13D shows a core 322 formed in a spiral 324 having a resulting spider web type shape 326. It is possible that in this or other configurations, portions of the material for forming the core may be thicker than others. In this specific spiral example, the inner portion of the spiral 328 may have a thinner cross section at its widest point then the portion of the spiral 330 located along the outermost section of the paddle. In one embodiment, the thickness of the material increases in a progressive manner as the material moves from the inner portion of the spiral 328 to the outer portion of the spiral 330. The increase may be at least about 20%, at least about 30%, at least about 40%, or even at least about 50% when comparing the inner portion 328 to the outer portion 330.

As a further example of biomimicry, FIGS. 14A-14D shows variations on exemplary paddle cores having a “tree-like” format. Each core includes one or more primary branch portion 332. Extending from each primary branch portion 332 are one or more secondary branch portions 334. In FIGS. 14A and 14D, tertiary branch portions 336 are shown extending from the secondary branch portions 334. At each point where a secondary branch portion 334 or tertiary branch portion 336 extends from a primary branch portion 332 or secondary branch portion 334 respectively, the branch portions may split in accordance with a unique ratio. This ratio may be in accordance with Murray's law. The ratio of the branches may be such that the radius of a primary branch portion cubed (or squared) is equal to the radius of the secondary branch portion cubed (or squared) plus the radius of the tertiary branch portion cubed (or squared) (r13=r23+r33 or r12=r22+r32). The use of such ratios may be optimal for providing light weight support and channeling energy and vibrations to the paddle handle/user for optimal responsiveness, feel, and/or performance. It is also possible that vibrations may be reduced along the branches.

As discussed herein, the paddle core may include a sandwich panel arrangement. Specific exemplary sandwich panel arrangements are shown in FIG. 15 and FIG. 16. FIG. 15 depicts sandwich panel structures 338, 342 that mimic a “bone-like” arrangement having meandering wall structures that curve to form cavities 340, 344 of varying sizes and shapes. FIG. 16 shows various sandwich panel constructions 346, each including a core portion 348 that includes a plurality of cavities 350 along a length of the core portion 348.

It is also desirable that recycled materials are used to form the paddle core. FIG. 17 shows a recycled cardboard grid arrangement for the core 352. The grid appears in a stacked format, where a first grid of cardboard having a plurality of first parallel ribs 354 is stacked onto a second grid of cardboard having a plurality of second parallel ribs 356 that are arranged perpendicular to the first parallel ribs 354. It is also possible that the cardboard (being a porous material) can be impregnated with a resin 358) that is adapted to adhere the grid portion to one or more facing sheets (not shown).

The material for forming a paddle core may include woven and nonwoven composite structures. These structures may be formed of materials that are specifically adapted for being coated and/or impregnated with a resin material, which may be a thermoplastic or thermoset resin and may have adhesive and/or foaming characteristics. FIG. 18 shows an exemplary woven core material 360 including a plurality of identical hexagonal cavities 362 formed by a plurality of wall structures 364. The wall structures 364 may include material 366 that is porous and able to absorb a resin. FIG. 19 shows similar woven materials 368 for forming a paddle core. Each sample 368 has a different thickness than the others and each includes top and bottom walls 372 and cavities 370 formed in between the top and bottom walls 372.

The present teachings describe the use of a variety of material for forming the paddles described herein and many of those materials are suitable for recycling or other forms of re-use. The entirety of the paddles described herein may be suitable for recycling or alternatively certain portions of the paddles may be suitable for recycling. As one non-limiting example, FIG. 20 shows a recycling flow chart for use of recycled paddle core materials. As shown, the paddle 374 is adapted for being ground into pellets 376. The pellets could be treated to have a desired appearance (dyed, bleached, coated, sprayed or the like). The pellets could be molded into balls 378 (which may be pickleball balls). The resulting balls could later be further recycled by being ground into pellets 380 and combined with the paddle pellets 376 to form more balls 378.

As utilized herein with respect to numerical ranges, the terms “approximately,” “about,” “substantially,” and similar terms generally mean+/−10% of the disclosed values, unless specified otherwise. As utilized herein with respect to structural features (e.g., to describe shape, size, orientation, direction, relative position, etc.), the terms “approximately,” “about,” “substantially,” and similar terms are meant to cover minor variations in structure that may result from, for example, the manufacturing or assembly process and are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the disclosure as recited in the appended claims.

It should be noted that the term “exemplary” and variations thereof, as used herein to describe various embodiments, are intended to indicate that such embodiments are possible examples, representations, or illustrations of possible embodiments (and such terms are not intended to connote that such embodiments are necessarily extraordinary or superlative examples).

The term “coupled” and variations thereof, as used herein, means the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent or fixed) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members coupled directly to each other, with the two members coupled to each other using a separate intervening member and any additional intermediate members coupled with one another, or with the two members coupled to each other using an intervening member that is integrally formed as a single unitary body with one of the two members. If “coupled” or variations thereof are modified by an additional term (e.g., directly coupled), the generic definition of “coupled” provided above is modified by the plain language meaning of the additional term (e.g., “directly coupled” means the joining of two members without any separate intervening member), resulting in a narrower definition than the generic definition of “coupled” provided above. Such coupling may be mechanical, electrical, or fluidic.

References herein to the positions of elements (e.g., “top,” “bottom,” “above,” “below”) are merely used to describe the orientation of various elements in the FIGURES. It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and that such variations are intended to be encompassed by the present disclosure.

Although the figures and description may illustrate a specific order of method steps, the order of such steps may differ from what is depicted and described, unless specified differently above. Also, two or more steps may be performed concurrently or with partial concurrence, unless specified differently above.

It is important to note that any element disclosed in one embodiment may be incorporated or utilized with any other embodiment disclosed herein Although only one example of an element from one embodiment that can be incorporated or utilized in another embodiment has been described above, it should be appreciated that other elements of the various embodiments may be incorporated or utilized with any of the other embodiments disclosed herein.

As used herein, unless otherwise stated, the teachings envision that any member of a genus (list) may be excluded from the genus; and/or any member of a Markush grouping may be excluded from the grouping.

Unless otherwise stated, any numerical values recited herein include all values from the lower value to the upper value in increments of one unit provided that there is a separation of at least 2 units between any lower value and any higher value. As an example, if it is stated that the amount of a component, a property, or a value of a process variable such as, for example, temperature, pressure, time and the like is, for example, from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, it is intended that intermediate range values such as (for example, 15 to 85, 22 to 68, 43 to 51, 30 to 32 etc.) are within the teachings of this specification. Likewise, individual intermediate values are also within the present teachings. For values which are less than one, one unit is considered to be 0.0001, 0.001, 0.01 or 0.1 as appropriate. These are only examples of what is specifically intended and all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be expressly stated in this application in a similar manner. As can be seen, the teaching of amounts expressed as “parts by weight” herein also contemplates the same ranges expressed in terms of percent by weight. Thus, an expression in the of a range in terms of at “x′ parts by weight of the resulting polymeric blend composition” also contemplates a teaching of ranges of same recited amount of “x” in percent by weight of the resulting polymeric blend composition.”

Unless otherwise stated, all ranges include both endpoints and all numbers between the endpoints. The use of “about” or “approximately” in connection with a range applies to both ends of the range. Thus, “about 20 to 30” is intended to cover “about 20 to about 30”, inclusive of at least the specified endpoints.

The disclosures of all articles and references, including patent applications and publications, are incorporated by reference for ail purposes. The term “consisting essentially of” to describe a combination shall include the elements, ingredients, components or steps identified, and such other elements ingredients, components or steps that do not materially affect the basic and novel characteristics of the combination. The use of the terms “comprising” or “including” to describe combinations of elements, ingredients, components or steps herein also contemplates embodiments that consist of, or consist essentially of the elements, ingredients, components or steps.

Plural elements, ingredients, components or steps can be provided by a single integrated element, ingredient, component or step. Alternatively, a single integrated element, ingredient, component or step might be divided into separate plural elements, ingredients, components or steps. The disclosure of “a” or “one” to describe an element, ingredient, component or step is not intended to foreclose additional elements, ingredients, components or steps.

It is understood that the above description is intended to be illustrative and not restrictive. Many embodiments as well as many applications besides the examples provided will be apparent to those of skill in the art upon reading the above description. The scope of the invention should, therefore, be determined not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. The disclosures of all articles and references, including patent applications and publications, are incorporated by reference for all purposes. The omission in the following claims of any aspect of subject matter that is disclosed herein is not a disclaimer of such subject matter, nor should it be regarded that the inventors did not consider such subject matter to be part of the disclosed inventive subject matter.

Composite Paddles and Methods for Forming same

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