Patent ID: 12246230

DETAILED DESCRIPTION

The present technology is directed to composite ball bats with transverse interlaminar interfaces, and associated systems and methods. Various embodiments of the technology will now be described. The following description provides specific details for a thorough understanding and enabling description of these embodiments. One skilled in the art will understand, however, that the invention may be practiced without many of these details. Additionally, some well-known structures or functions, such as those common to ball bats and composite materials, may not be shown or described in detail to avoid unnecessarily obscuring the relevant description of the various embodiments. Accordingly, embodiments of the present technology may include additional elements or exclude some of the elements described below with reference toFIGS.1-7, which illustrate examples of the technology.

The terminology used in this description is intended to be interpreted in its broadest reasonable manner, even though it is being used in conjunction with a detailed description of certain specific embodiments of the invention. Certain terms may even be emphasized below; however, any terminology intended to be interpreted in any restricted manner will be overtly and specifically defined as such in this detailed description section.

Where the context permits, singular or plural terms may also include the plural or singular term, respectively. Moreover, unless the word “or” is expressly limited to mean only a single item exclusive from the other items in a list of two or more items, then the use of “or” in such a list is to be interpreted as including (a) any single item in the list, (b) all of the items in the list, or (c) any combination of items in the list. Further, unless otherwise specified, terms such as “attached” or “connected” are intended to include integral connections, as well as connections between physically separate components.

For purposes of the present disclosure, a first element that is positioned “toward” an end of a second element is positioned closer to that end of the second element than to a middle or mid-length location of the second element.

Specific details of several embodiments of the present technology are described herein with reference to ball bats. Embodiments of the present technology can be used in baseball, softball, cricket, or other similar sports in which an implement hits a ball.

As shown inFIG.1, a baseball or softball bat100, hereinafter collectively referred to as a “ball bat” or “bat,” includes a barrel portion110, a handle portion120, and a tapered section130joining the handle portion120to the barrel portion110along a longitudinal axis x. The tapered section130transitions the larger diameter of the barrel portion110to the narrower diameter of the handle portion120. The tapered section130may include parts of the barrel portion110or the handle portion120, such that the barrel portion110is attached to, or continuous with, the handle portion120. The handle portion120optionally includes a knob140or similar structure positioned at a proximal end145of the bat100. An optional end cap150or other suitable plug may close off the barrel portion110at a distal end155of the bat100(for purposes of this disclosure, the “distal end” is the end of an embodiment farthest from a user). The barrel portion110may include a non-tapered or straight section160extending between the end cap150and a location170.

The interior of the bat100is optionally hollow, allowing the bat100to be relatively lightweight so that ball players may generate substantial bat speed when swinging the bat100. A hitting surface or ball striking area180of the bat100typically extends throughout the length of the barrel portion110, and may extend partially into the tapered section130of the bat100. The bat100generally includes a “sweet spot”190, which is the impact location where the transfer of energy from the bat100to a ball is generally maximal, while the transfer of energy to a player's hands is generally minimal. The sweet spot190is typically located near the bat's center of percussion (COP), which may be determined by the ASTM F2398-11 Standard. For ease of measurement and description in the present application, the sweet spot190described herein coincides with the bat's COP.

The proportions of the bat100, such as the relative sizes of the barrel portion110, the handle portion120, and the tapered section130, are not drawn to scale and may have any relative proportions suitable for use in a ball bat. Accordingly, the bat100may have any suitable dimensions. For example, the bat100may have an overall length of 20 to 40 inches, or 26 to 34 inches. The overall barrel portion110diameter may be 2.0 to 3.0 inches, or 2.25 to 2.75 inches. Typical ball bats have barrel diameters of 2.25, 2.625, or 2.75 inches. Bats having various combinations of these overall lengths and barrel diameters, or any other suitable dimensions, are contemplated herein. The specific preferred combination of bat dimensions is generally dictated by the user of the ball bat100, and may vary greatly among users. For purposes of orientation and context for the description herein,FIG.1also illustrates a radial z-axis. The z-axis is orthogonal to the longitudinal x-axis and extends radially through the wall thickness of the bat100.

Components of the ball bat100may be constructed from one or more composite or metallic materials. Some examples of suitable composite materials include laminate layers or plies reinforced with fibers of carbon, glass, graphite, boron, aramid (such as Kevlar®), ceramic, or silica (such as Astroquartz®). Suitable metallic materials include aluminum, titanium, or another suitable metallic material.

For convenience of description and to assist the reader with understanding embodiments of the present technology, some aspects of construction of a ball bat100are first described below, followed by descriptions of embodiments of ball bats that may be formed using aspects of construction techniques according to the present technology. Methods of making ball bats according to embodiments of the present technology are also disclosed.

FIG.2illustrates a side view of a partially assembled ball bat100configured in accordance with embodiments of the present technology. In some embodiments, the ball bat100includes a preform structure200and a fiber tape210wrapped around at least a portion of the preform structure200. The preform structure200extends along the longitudinal axis x and may be generally shaped like a finished ball bat100(for example, it may have a barrel shape, a handle shape, and a tapered section shape). The preform structure200may be formed with composite laminate material or other suitable composite materials.

In some embodiments, a flared element230(illustrated as being beneath the fiber tape210) is positioned on, or integral with, the preform structure200toward the distal end155. The flared element230has a surface240(also illustrated as being beneath the fiber tape210) that diverges or tapers away from the longitudinal axis x as it extends away from the proximal end145and toward the distal end155. As explained in detail below, the flared element230may be formed as a discrete wedge element (such as a ring having a wedge-shaped cross-section) permanently or temporarily attached to the distal end155of the preform structure200. In some embodiments in which the flared element230is integral with the preform structure200, it may be a flared portion of the preform structure200having the characteristics of the flared element230.

The surface240is angled transverse to the longitudinal axis x. The flared element230and the surface240provide a starting point for wrapping the fiber tape210around the preform structure200in a helix that extends along the longitudinal axis x. Because the surface240of the flared element230is angled relative to the remainder of the preform structure200, consecutive turns (wraps) of the fiber tape210form overlapping layers235of the fiber tape210that are also angled (oriented transversely) relative to the preform structure200. Likewise, interlaminar interfaces250between consecutive turns or layers235are oriented transversely relative to the longitudinal axis x and to the preform structure200.

The angled layers235of fiber tape210form a portion of the thickness of a wall of the ball bat100. Accordingly, a ball bat100configured in accordance with embodiments of the present technology includes a barrel wall with interlaminar interfaces250that are orthogonal or transverse to the x-axis of the bat100, which yields components that extend at least partially in a radial or z-direction, and also positions fibers of the fiber tape210at least partially along a radial or z-direction. The angled nature of the layers235, the interlaminar interfaces250, and the fibers within the fiber tape210provides an improved balance of hoop strength and axial strength in the barrel wall relative to existing composite bat technologies that use concentric composite layers (in which the interlaminar interfaces extend along the x-axis). Manufacturing the angled components of embodiments of the present technology is advantageously relatively simple at least because it involves wrapping a single continuous fiber tape210around the preform200.

The fiber tape210is a tape (strip) of fiber material (such as carbon fiber, fiberglass, aramid, flax, or other fibers suitable for use in composite materials), which may or may not include a resin or matrix material. For example, the fiber tape210may be a prepreg material (uncured material pre-impregnated with resin material or other suitable composite matrix materials) that is manipulated into position before curing, either co-curing with the preform structure200or curing at a different time than the preform structure200.

In some embodiments, the fiber tape210may be a fiber material without resin or matrix material and it may have the resin or matrix applied and cured through known composite manufacturing techniques. In some embodiments, the fiber tape210may include unidirectional fiber tape. The fiber tape210may include fiber angles (the angle of the fiber within the tape relative to the length of the tape) of 45 degrees, or other suitable angles. Fiber angles of approximately 45 degrees provide resistance to fraying when wrapping around the preform200. In some embodiments, the fiber tape210may include braided fiber tape. Generally, composite materials forming the fiber tape210and the preform structure200may be conventional composite materials.

FIG.3illustrates a side cross-sectional view of a portion of the ball bat100, configured in accordance with embodiments of the present technology.FIG.4is a detailed view of the outlined section labeled “SEEFIG.4” inFIG.3. With reference to bothFIGS.3and4, the preform structure200may be formed with composite laminate material or other suitable composite materials. In some embodiments, the preform structure200comprises a plurality of concentric layers of composite laminate material forming a preform wall300.

In some embodiments, the preform wall300has a uniform thickness t along its length. In other embodiments, the preform wall300has non-uniform or varying thickness along its length, such as a section310where the preform wall300has a greater thickness t2than the remaining thickness t of the preform wall300. The section310may include the inner surface320of the preform wall310extending radially inwardly toward the longitudinal axis x, and it may optionally include tapering between thicknesses t and t2. The section310may be located at or adjacent to the sweet spot190. In some embodiments that include a preform wall300which has variable or non-uniform thickness along its length, an overall thickness t3of the barrel wall may be maintained regardless of the preform wall thickness by adjusting the overlap of the fiber tape210(the thickness t3includes: the radial thickness of the preform wall300, such as the thickness t or t2; the radial thickness t4of the fiber tape210when it is wrapped around the preform wall300; and the radial thickness of the outer skin330described below, if any). For example, less overlap of wraps of tape210can compensate for a thicker preform wall, or more overlap can compensate for a thinner preform wall, to maintain desired or consistent wall thickness.

In some embodiments, the fiber tape210is wrapped around the preform structure200in a helix that extends through the full striking area180of the ball bat100. In some embodiments, the helix may extend only through part of the striking area180, such as only along a full length of the barrel portion110. In some embodiments, as shown inFIGS.3and4, the helix of fiber tape210may extend through only part of the striking area180or along only a portion of the longitudinal axis x of the ball bat. For example, the helix of fiber tape210may extend from near (such as within one to three inches of) the sweet spot190to the distal end155. In some embodiments, the fiber tape210is positioned to extend from the distal end155toward the proximal end145by three to ten inches, depending in part on the size of the ball bat100. In some embodiments, the fiber tape210extends along a full length of the ball bat100. A single fiber tape210wrapped in a helix that is positioned to extend along the full striking area180tends to provide increased durability because there is not an area of discontinued fibers of the tape (where the tape ends) within the striking area180. A single fiber tape210wrapped in a helix along the full striking area180also tends to be easier to manufacture than shorter tape (a shorter helix) or a plurality of tapes.

The flared element230may be a discrete ring-shaped wedge element, although, as explained above, the flared element230may be integral to the preform structure200. In some embodiments, the flared element230is formed with the same material as the preform structure200. In other embodiments, the flared element230is made of wood, plastic (such as thermoplastic polyurethane), metal, foam, composite material, or another material suitable for providing the angled aspect of the flared element230and suitable for receiving an end of the fiber tape210.

In some embodiments, the wrapped fiber tape210forms the outermost surface of the ball bat100(setting aside paint or indicia). In other embodiments, the ball bat100includes an outer skin330positioned over the wrapped fiber tape210to form the outermost surface of the ball bat100(setting aside paint or indicia). The outer skin330forms an exterior cover that may provide a smooth outer surface or it may further modify the structural characteristics of the bat100. For example, an outer skin330may add durability, axial stiffness, and improved feel relative to embodiments in which there is no outer skin330.

Because the helix of fiber tape210may extend only a partial length of the ball bat along the longitudinal axis x (for example, from the distal end155to a tape end340), there may be an external or surface shape discontinuity adjacent to the tape end340. To avoid such a shape discontinuity, in some embodiments, the bat100includes one or more composite layers350(such as composite laminate layers) positioned on the preform200or integral with the preform200adjacent to the tape end340along the longitudinal axis x. The one or more composite layers350may extend along the longitudinal axis x between the tape end340and a location within the tapered section130, or the one or more composite layers350may extend all the way to the proximal end145of the ball bat100. In some embodiments, the outer skin330is also positioned over the one or more composite layers350.

AlthoughFIGS.3and4show the flared element230positioned at or toward the distal end155, in some embodiments, the flared element230may be positioned elsewhere along the length of the ball bat100.

For example,FIG.5illustrates a side cross-sectional view of a portion of a ball bat500configured in accordance with further embodiments of the present technology, in which the flared element230is positioned at a distance d from the distal end510of the bat500. The ball bat500may be similar to the ball bat100described above, except that the fiber tape210does not extend to the distal end510. Instead, for example, one or more concentric composite laminate layers520that extend generally parallel to the x-axis may be positioned between the fiber tape210(or the flared element230) and the distal end510. Accordingly, in various embodiments, the fiber tape210may form any suitable portion of a ball bat, such as some or all of the barrel portion110, some or all of the handle portion120, or some or all of the tapered section130(seeFIG.1). In the embodiment shown inFIG.5, the fiber tape210may extend from a location between the sweet spot190and the distal end510(the location being spaced apart from the distal end510) to a location between the sweet spot190and the proximal end145(seeFIG.1) of a ball bat.

Generally, in embodiments in which the fiber tape210does not span a full length of a ball bat, other composite material may be positioned adjacent to the fiber tape210(such as the one or more composite laminate layers350between the fiber tape210and the proximal end145of the bat100, as shown inFIG.3, or the one or more composite laminate layers520between the fiber tape210and the distal end510of the bat500as shown inFIG.5, or other combinations or arrangements of fiber tape210and composite laminate layers).

FIG.6is a schematic cross-sectional view of the preform wall300, the flared element230, and two layers235of fiber tape210(formed by at least one wrap or turn of the helix of fiber tape210). An angle A is illustrated inFIG.6to represent the angle between the surface240and the preform wall300. Because the preform wall300is generally parallel to the x-axis at the location of the flared element230, the angle A also represents the angle between the surface240and the x-axis. Likewise, the angle A represents the angle between the layers235of fiber tape210and the x-axis, as well as the angle between the interlaminar interface250and the x-axis. The angle A may be between 1 and 90 degrees.

A 90-degree angle A would orient the interfaces250between the layers235to be perpendicular to the x-axis. Such a 90-degree angle A, however, presents manufacturing challenges and may reduce durability and axial strength. For example, as the angle A approaches 90 degrees, the tape210may stretch or wrinkle on its sides more than it would at lesser angles, because opposite sides of the tape210would be forced to have different radial locations from each other. Although the tape210may be pleated at its outer radius to adjust for such stretching or wrinkling, pleating reduces the strength of the tape210and increases complexity in the manufacturing process. Generally, oblique angles (greater than one degree and less than 90 degrees) are preferred, but it is noted that as the angle A is reduced, fewer manufacturing challenges may arise (as the radial difference between edges of the tape120is reduced).

In some embodiments, the angle A may be 45 degrees, which provides a balance of hoop and axial strength. Such an angle A, however, may require more tape material to assemble a ball bat. Angles A less than 45 degrees present manageable manufacturing challenges while still providing the advantageous effect of interfaces250between layers235formed by wraps or turns of the tape210oriented transverse to the x-axis. In one embodiment, an angle A of 11 degrees, with a tape width W of one inch, presents a good compromise between strength and manufacturability.

Although a bat preform200is described as receiving the fiber tape210, in some embodiments, the preform200may be omitted and the fiber tape210may form some or all of the full thickness of a bat wall. In such embodiments, a mandrel (with a flared element230) may replace the preform200, and the fiber tape210may be wrapped around the mandrel. The mandrel may be removed before or after curing the fiber tape210. Accordingly, the preform200or mandrel may form a base structure about which the fiber tape210is wrapped.

FIG.6Aillustrates a table600of example angles A (column605) and tape widths W (column610) that may be implemented in a bat configured in accordance with some embodiments of the present technology. In the table600, the angles A (column605) and tape widths W (column610) correspond to a tape wrap radial thickness t4(seeFIG.4) of approximately 0.25 inches (column615). The dimensions and values in the table600are for example only and do not limit the embodiments or implementations of the present technology. Rather, the table600illustrates some configurations of bats configured in accordance with various embodiments of the technology.

In some embodiments, the angle A may be a function of the tape width W and the overall bat wall thickness (for example, t3inFIG.4). For example, for a selected preform wall300thickness and a selected outer skin330thickness, if the tape width W is narrowed while keeping the overall bat wall thickness the same, the angle A may be greater and may require more wraps (turns) of the fiber tape210to cover the desired length of the bat. The additional wraps (turns) can increase the time, material, and complexity of the manufacturing process. For example, as explained in additional detail above, the greater angle A can distort the tape as it wraps in a circular pattern by stretching one side and compressing the other side. Accordingly, a greater angle A may also include a need for specially tailoring the tape210to allow for such distortion (such as stretching or compression). A person of ordinary skill in the art will be able to select a desired angle A, tape width W, overall bat wall thickness t3, or dimensions of other elements for a desired application of embodiments of the present technology.

FIG.7illustrates a method700of making a ball bat in accordance with embodiments of the present technology. Beginning at block702, an operator may create a bat preform (such as the preform200) or provide a mandrel. If the flared element is not integral with the preform or mandrel, the flared element may be installed at block704. At block706, an operator may begin wrapping the fiber tape by attaching it to, or otherwise placing it on, the flared element.

At block708, an operator may wrap the fiber tape as a helix around the preform or mandrel until it extends along the desired length of the bat. At block710, an operator may optionally cover the fiber tape with a skin layer. At block712, the assembly is cured. In some embodiments, some or all elements of the assembly (such as the preform, the flared element, the tape, or the skin) may be co-cured, while in other embodiments, various elements may be cured at different times.

In some embodiments, at block714, an operator may cut off the end of the assembly having the flared element to remove the flared element or wedge (leaving only the angled layers of wrapped fiber tape). In other embodiments, the flared element may remain in the assembly and be a permanent part of the final bat. At block716, an operator may finish the bat by adding an end knob, end cap, indicia, or other elements. Steps of the method700may be performed in other suitable sequences and may include additional steps or may omit steps.

Bats configured in accordance with embodiments of the present technology provide several advantages. For example, the interlaminar interfaces between consecutive turns of the fiber tape210are oriented transversely relative to the x-axis, which helps to reduce or limit the trampoline effect of a bat as it breaks in, relative to interlaminar interfaces that are oriented along the x-axis. Accordingly, ball bats according to the present technology provide more consistent performance before and after being “broken in.”

From the foregoing, it will be appreciated that specific embodiments of the disclosed technology have been described for purposes of illustration, but that various modifications may be made without deviating from the technology, and elements of certain embodiments may be interchanged with those of other embodiments, and that some embodiments may omit some elements. For example, although in some embodiments, the fiber tape210may be discontinuous, the fiber tape210is preferably one single continuous tape such that only one fiber tape210is used to form the transverse interlaminar interfaces described above. A single continuous tape of fiber material helps reduce complexity and waste in the manufacturing process. A single continuous tape of fiber material also helps reduce discontinuities along the bat surface. Because such discontinuities can reduce durability and increase the risk of undesirable performance growth, a single continuous tape can improve durability and control performance relative to a discontinuous tape. Accordingly, embodiments of the present technology include a single continuous tape of fiber material or a minimal quantity of continuous tapes of fiber material to minimize the quantity of discontinuities between tapes. In some embodiments, the straight section160includes a single continuous tape, the barrel portion110includes a single continuous tape, the ball striking area180includes a single continuous tape, or other sections or portions of a ball bat can include a single continuous tape.

Further, while advantages associated with certain embodiments of the disclosed technology have been described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the technology. Accordingly, the disclosure and associated technology may encompass other embodiments not expressly shown or described herein, and the invention is not limited except as by the appended claims.