A variety of inflatable sport balls, such as a soccer ball, conventionally exhibit a layered structure that includes a casing, an intermediate layer, and an inflatable bladder. The casing forms an exterior layer of the sport ball and is generally formed from a plurality of durable, wear-resistant panels joined together along abutting edges (e.g., with stitching or adhesives). Although panel configurations may vary significantly, the casing of a traditional soccer ball includes thirty-two panels, twelve of which have a pentagonal shape and twenty of which have a hexagonal shape. The intermediate layer forms a middle layer of the sport ball and is positioned between the bladder and the casing. The bladder, which has an inflatable configuration, is located within the intermediate layer to provide an inner layer of the sport ball. In order to facilitate inflation (i.e., with air), the bladder generally includes a valved opening that extends through each of the intermediate layer and casing, thereby being accessible from an exterior of the sport ball.
The intermediate layer of a conventional sport ball may have a variety of configurations. As an example, a conventional intermediate layer may be formed from multiple material layers that include (a) a compressible foam layer located adjacent to the casing to impart a softened feel to the sport ball, (b) a rubber layer that imparts energy return, (c) a textile layer with a limited degree of stretch in order to restrict expansion of the bladder, and (d) multiple adhesive layers that extend between and join the foam, rubber, and textile layers. Although the intermediate layers of some sport balls incorporate each of these layers, one or more of these layers may be absent. Moreover, the configuration of the individual layers may vary significantly. For example, the textile layer may be formed from (a) a plurality of generally flat or planar textile elements that are stitched together, (b) a thread, yarn, or filament that is repeatedly wound around the bladder in various directions to form a mesh, or (c) a plurality of generally flat or planar textile strips that are impregnated with latex and placed in an overlapping configuration around the bladder. The various layers of the intermediate layer may also be bonded, joined, or otherwise incorporated into the casing as a backing material.
A sport ball may include a casing, an intermediate layer, and a bladder. The casing forms at least a portion of an exterior surface of the ball. The intermediate layer is at least partially formed from a foam material located adjacent to the casing and within the casing. The bladder has an inflatable configuration and is located adjacent to the intermediate layer and within the intermediate layer. The foam material of the intermediate layer may be bonded to each of the casing and the bladder.
In manufacturing a sport ball, a bladder may be located in a mold and a polymer foam material may be injected into the mold and onto a surface of the bladder. In some configurations, panel elements may also be located within the mold, and the polymer foam material may be injected into an area between the bladder and the panel elements. In addition, edges of the panel elements may be heatbonded to each other to join the panel elements and form a casing of the sport ball.
The advantages and features of novelty characterizing aspects of the invention are pointed out with particularity in the appended claims. To gain an improved understanding of the advantages and features of novelty, however, reference may be made to the following descriptive matter and accompanying figures that describe and illustrate various configurations and concepts related to the invention.
The foregoing Summary and the following Detailed Description will be better understood when read in conjunction with the accompanying figures.
The following discussion and accompanying figures disclose various sport ball configurations and methods of manufacturing the sport balls. Although the sport ball configurations are discussed and depicted in relation to a soccer ball, concepts associated with the configurations and methods may be applied to various types of inflatable sport balls. In addition to soccer balls, therefore, concepts discussed herein may be incorporated into basketballs, footballs (for either American football or rugby), and volleyballs, for example. A variety of non-inflatable sport balls, such as baseballs, softballs, and golf balls, may also incorporate concepts discussed herein.
Sport Ball Structure
A sport ball 10 with the configuration of a soccer ball is depicted in
The materials selected for casing 20 may be leather, polyurethane, polyvinyl chloride, various other thermoplastic or thermoset materials, or other suitable materials, whether synthetic or natural, that are generally durable and wear-resistant. In some configurations, each of panels 21 may have a layered configuration that combines two or more materials. For example, an exterior portion of each panel 21 may be formed from polyurethane, and an interior portion of each panel 21 may be formed from a textile element 23, as depicted in
An advantage of casing 20 relates to the manner in which panels 21 are joined to form seams 22. The panels of conventional sport balls may be joined with stitching (e.g., hand or machine stitching). Although panels 21 may be joined through stitching in some configurations, a heatbonding method is utilized in ball 10 to join panels 21 and form seams 22. More particularly, panels 21 may be formed from a thermoplastic material, and edges of panels 21 may be heated and bonded to each other to form seams 22. An advantage of heatbonding when forming seams 22 relates to the overall mass of ball 10. Whereas approximately ten to fifteen percent of the mass of a conventional sport ball may be from the seams between panels, heatbonding panels 21 may reduce the mass at seams 22. By eliminating stitched seams in casing 20, the mass that would otherwise be imparted by the stitched seams may be utilized for other structural elements that enhance the performance properties (e.g., energy return, sphericity, mass distribution, durability, aerodynamics) of ball 10.
Intermediate layer 30 forms a middle layer of ball 10 that is positioned between casing 20 and bladder 40. As discussed in the Background section above, conventional intermediate layers are formed from foam, rubber, textiles, and adhesive layers. In comparison,
An advantage of the configuration of intermediate layer 30 relates to the overall mass of intermediate layer 30. A conventional intermediate layer may be formed from multiple material layers that include (a) a compressible foam layer, (b) a rubber layer, (c) a textile layer, and (d) multiple adhesive layers that extend between and join the foam, rubber, and textile layers, as discussed in the Background section above. In some conventional sport balls, the mass of the adhesive layers may impart approximately twenty-five percent of the total mass of the sport balls. That is, the adhesive layers alone account for twenty-five percent of the total mass of the sport balls. By eliminating the adhesive layers in intermediate layer 30, the mass that would otherwise be imparted by the adhesive layers may be utilized for other structural elements that enhance the performance properties (e.g., energy return, sphericity, mass distribution, durability, aerodynamics) of ball 10.
Bladder 40 has an inflatable configuration and is located within intermediate layer 30 to provide an inner portion of ball 10. When inflated, bladder 40 exhibits a rounded or generally spherical shape. In order to facilitate inflation, bladder 40 may include a valved opening (not depicted) that extends through intermediate layer 30 and casing 20, thereby being accessible from an exterior of ball 10, or bladder 40 may have a valveless structure that is semi-permanently inflated. Bladder 40 may be formed from a rubber or carbon latex material that substantially prevents air or other fluids within bladder 40 from diffusing to the exterior of ball 10. In addition to rubber and carbon latex, a variety of other elastomeric or otherwise stretchable materials may be utilized for bladder 40.
Inflating bladder 40 induces ball 10 to take on a substantially spherical shape. More particularly, fluid pressure from air within bladder 40 causes bladder 40 to expand and place an outward force upon intermediate layer 30. In turn, intermediate layer 30 places an outward force upon casing 20. In order to limit the expansion of bladder 40 and also limit tension in casing 20, intermediate layer 30 may have a limited degree of stretch. That is, intermediate layer 30 may be formed from a foam material that has a limited degree of stretch. Alternately, textile elements 23 and 31, reinforcing structure 32, or one or both of foam layers 33 and 34 may exhibit a limited degree of stretch. In any of these configurations, the stretch characteristics of intermediate layer 30 may prevent the expansion of bladder 40 from inducing significant tension in casing 20. Accordingly, intermediate layer 30 may restrain the expansion of bladder 40, while permitting outward forces to induce a substantially spherical shape in casing 20, thereby imparting a substantially spherical shape to ball 10. In some configurations, however, bladder 40 may incorporate a tensile element 41 that restrains the overall expansion of bladder 40 and limits the tension in casing 20, as depicted in
Construction Method
A variety of construction methods may be utilized for ball 10. As an example of a suitable construction method, a polymer foam material is injected into a space between a panel blank 50 and bladder 40. Referring to
A mold 60 that may be utilized in constructing ball 10 is depicted in
The manner in which mold 60 is utilized in constructing ball 10 will now be discussed with reference to
Once panel blank 50 is properly positioned, bladder 40 is inflated to a generally spherical shape having a diameter that is substantially equal to the diameter of bladder 40 within ball 10. Bladder 40 is then positioned to contact outer surface 61, as depicted in
A gap 67 extends between bladder 40 and panel area 51 when (a) bladder 40 is positioned in contact with outer surface 61 and (b) panel blank 50 is positioned in contact with central surface 62, as depicted in
Once foam material 66 is located within gap 67, foam material 66 may begin curing and bonding with the surfaces of bladder 40 and panel area 51, thereby forming a portion of intermediate layer 30. The combination of bladder 40, panel blank 50, and foam material 66 may then be withdrawn from mold 60, as depicted in
The general process discussed above may then be repeated to bond additional panel blanks 50 to bladder 40 with foam material 66, as depicted in
Seam Formation
Following the injection of foam material 66, which becomes intermediate layer 30, seams 22 are formed between adjacent flange areas 52. Referring to
A die 70 that may be utilized in forming seams 22 is depicted in
A method of utilizing die 70 to form seams 22 is depicted in
As utilized herein, the term “heatbonding”, or variants thereof, is defined as a securing technique between two elements that involves a melting or softening of at least one of the elements such that the materials of the elements are secured to each other when cooled. In general, heatbonding may involve the melting or softening of the adjacent flange areas 52 (or other portions of panel blanks 50) such that the materials diffuse across a boundary layer between flange areas 52 and are secured together when cooled. Heatbonding may also involve the melting or softening of only one flange area 52 such that the molten material extends into crevices or cavities formed by the other flange area 52, thereby securing the components together when cooled. Accordingly, heatbonding does not generally involve the use of stitching or adhesives. Rather, two elements are directly bonded to each other with heat. In some situations, however, stitching or adhesives may be utilized to supplement the joining of elements through heatbonding.
A variety of processes may be utilized to heatbond the abutting flange areas 52. For example, die 70 may incorporate heating elements that raise the temperature of portions 71, thereby conducting heat to flange areas 52. As another example, die 70 may emit radio frequency energy (RF energy) that heats flange areas 52. More particularly, the radio frequency energy may pass between facing surfaces 73 and through flange areas 52. When irradiated with the radio frequency energy, the temperature of the polymer material forming flange areas 52 increases until melting and softening occurs. Given that flange areas 52 are also compressed between facing surfaces 73, the increased temperature facilitates the formation of a heatbond between flange areas 52.
As noted above, portions 71 press into ball 10 at this stage of forming seams 22. More particularly, protrusions 72 press into ball 10. Although seams 22 may be formed at a position that corresponds with the surfaces of panel areas 51 (i.e., panels 21), protrusions 72 ensure that seam 22 is recessed into the surface of ball 10. That is, indentations are formed in ball 10 at seams 22. An advantage of this configuration is that seams 22 are less likely to experience wear as ball 10 rubs or otherwise abrades against the ground or other surfaces or objects. That is, protrusions ensure that seams 22 are recessed relative to a remainder of panels 21 in order to enhance the overall durability of ball 10.
Once flange areas 52 are bonded together, portions 71 may retract from ball 10, as depicted in
The general process of bonding flange areas 52 together and removing excess portions of flange areas 52 may be performed at each interface between panel blanks 50 to effectively form panels 21 and seams 22 (i.e., to form casing 20), thereby substantially completing the manufacture of ball 10.
Additional Construction Methods
The construction method discussed above provides an example of a suitable method for constructing ball 10. A variety of other methods may also be utilized. Referring to
In utilizing mold 80 to construct ball 10, various panel blanks 50 are located within cavity 83 such that (a) panel areas 51 are adjacent to a surface of cavity 83 and (b) flange portions 52 extend into indentations 84, as depicted in
In another construction method, a mold 90 may be utilized to construct ball 10. Referring to
In utilizing mold 90 to construct ball 10, bladder 40 is inflated to a generally spherical shape having a diameter that is substantially equal to the diameter of bladder 40 within ball 10. Bladder 40 is then located within cavity 93 and in a position that is spaced from a surface of cavity 93, as depicted in
Conclusion
Based upon the above discussion, intermediate layer 30 of ball 10 is at least partially formed from a foam material and located adjacent to casing 20 and within casing 20. Bladder 40 is located adjacent to intermediate layer 30 and within intermediate layer 30. In this configuration, the foam material of intermediate layer 30 may be bonded to each of casing 20 and bladder 40. In manufacturing ball 10, bladder 40 and a casing element (e.g., one of panels 21 or one of panel blanks 50 are located within a mold, with at least a portion of a surface of the casing element being spaced from a surface of bladder 40. A polymer foam material is then injected into the mold and between bladder 40 and the casing element. In addition, the casing elements may include a thermoplastic polymer material, and the casing elements may be heatbonded to each other to form seams 22.
The invention is disclosed above and in the accompanying drawings with reference to a variety of configurations. The purpose served by the disclosure, however, is to provide an example of the various features and concepts related to the invention, not to limit the scope of the invention. One skilled in the relevant art will recognize that numerous variations and modifications may be made to the configurations described above without departing from the scope of the present invention, as defined by the appended claims.