Patent Application
20120137769
The present invention relates to systems and methods for evaluating a golf ball design, and more particularly, to systems and methods for rapidly manufacturing and evaluating a test golf ball that mimics the performance of a final desired golf ball using a substitute material in a one-piece or multi-piece golf ball having substantially the same dimple design and specific gravity of the desired final golf ball design.
Golf ball manufacturers continually strive to improve the performance of golf balls, for example, in terms of travel distance and control. While a golf ball may appear simple in shape, the many possible variations in surface features greatly affect a golf ball's performance. Slight adjustments in dimple patterns, shapes, and sizes may yield widely varying performance characteristics. Thus, traditionally, the golf ball design process has largely involved a trial and error approach, in which prototypes of proposed golf ball designs are first made as nonfunctional prototypes, which are evaluated for their visual appearance and are not suitable for testing, such as aerodynamic testing. After the visual evaluation, actual functional golf ball prototypes are manufactured in small batches using the same complicated manufacturing processes used to produce commercially-sold golf balls. The small batch of functional golf ball prototypes is then performance-tested. The traditional prototyping processes, from conception to prototype, therefore typically require extensive resources to manufacture molds and to injection mold multiple layers of the golf balls, which often have two- or three-piece constructions. Moreover, the first prototypes rarely provide the desired results, necessitating changes in the design and further prototyping and testing.
Consequently, the traditional prototyping approaches typically require a substantial commitment of money and time, and may undesirably delay a product's introduction to the market. During the research and development phase, when a manufacturer is considering many different golf ball designs and the designs are rapidly changing, the conventional prototyping techniques may significantly hinder a manufacturer from swiftly bringing new designs to the market. Manufacturers therefore desire the ability to quickly and conveniently test and evaluate proposed golf ball designs, to efficiently identify golf ball surface designs that optimize performance.
Embodiments provide systems and methods for evaluating a golf ball design, which form a test golf ball using a substitute material in a one-piece or multi-piece golf ball having the same dimple design and specific gravity of a desired final golf ball design. The systems and methods may provide a limited-use golf ball that mimics the dimple design and specific gravity of a desired final golf ball design while being able to withstand several impacts as necessary for testing. The systems and methods may involve determining the overall specific gravity of the desired final golf ball design and formulating a material that mimics the overall specific gravity in a one-piece or multi-piece construction and that is suitable for testing.
One aspect provides a method for evaluating a golf ball design. The method may include designing a proposed golf ball having a size, a dimple design, and a multi-layered construction, the proposed golf ball comprising the golf ball design. A specific gravity of the proposed golf ball may be determined. A material for a test golf ball may be selected. The material may provide the test golf ball with a specific gravity substantially equal to the specific gravity of the proposed golf ball, when the material is formed into a monolithic test golf ball having substantially the same size and dimple pattern as the proposed golf ball. The selected material may be formed into the monolithic test golf ball. The monolithic test golf ball may then be tested to evaluate the golf ball design.
In another aspect, the proposed golf ball may have a two-piece construction or a three-piece construction.
In another aspect, selecting the material may comprise selecting a base material having a base material specific gravity, and doping the base material to change the base material specific gravity to substantially equal the specific gravity of the proposed golf ball.
In another aspect, the base material may comprise one of acrylonitrile-butadiene-styrene plastic and polyoxymethylene plastic.
In another aspect, forming the selected material into the monolithic test golf ball may comprise forming the selected material into a block; machining the block into a golf ball blank substantially equal in size to the size of the proposed golf ball; and machining the dimple design of the proposed golf ball into the golf ball blank.
In another aspect, machining the block into the golf ball blank may comprise forming index tabs on the golf ball blank, machining the dimple design into the golf ball blank may comprise aligning the dimple design using the index tabs, and the method may further comprise removing the index tabs after machining the dimple design into the golf ball blank.
In another aspect, forming the selected material into the monolithic test golf ball may comprise forming a mold corresponding to the size and dimple design of the proposed golf ball; injecting the selected material in liquid form into the mold; cooling the material to solidify the material into the size and dimple design of the proposed golf ball to form the monolithic test golf ball; and removing the monolithic test golf ball from the mold.
In another aspect, testing the monolithic test golf ball may comprise determining aerodynamic properties of the test golf ball.
In another aspect, the aerodynamic properties may include a coefficient of lift and a coefficient of drag.
In another aspect, testing the monolithic test golf ball may comprise subjecting the monolithic test golf ball to at least fifteen impacts, and selecting the material may comprise selecting a material that withstands the at least fifteen impacts when formed into the monolithic test golf ball.
In another aspect, selecting the material may comprise selecting a material that, when formed in the size and dimple design of the proposed golf ball, provides a monolithic test golf ball having a mass substantially equal to a computed mass of the proposed golf ball.
Another aspect provides another method for evaluating golf ball designs. A proposed golf ball having an outer spherical shape and a multi-layered construction may be designed. A specific gravity of the proposed golf ball may be determined. A test golf ball having the outer spherical shape and a one-piece construction may be designed. A material that provides the test golf ball with a specific gravity substantially equal to the specific gravity of the proposed golf ball may be selected. A plurality of monolithic golf ball blanks may be formed from the selected material to provide an inventory of monolithic golf ball blanks, each of the monolithic golf ball blanks having an outer spherical shape substantially equal to the outer spherical shape of the proposed golf ball. A first dimple design for the proposed golf ball may be designed. The first dimple design may be formed into a first monolithic golf ball blank of the plurality of monolithic golf ball blanks to form a first test golf ball. The first test golf ball may then be tested to evaluate the first dimple design. A second dimple design for the proposed golf ball may be designed based on test results of the first test golf ball. The second dimple design may be formed into a second monolithic golf ball blank of the plurality of monolithic golf ball blanks to form a second test golf ball. The second test golf ball may then be tested to evaluate the second dimple design.
In another aspect, the proposed golf ball may comprise a first proposed golf ball and the plurality of monolithic golf ball blanks may comprise a plurality of first monolithic golf ball blanks, and the method may further comprise designing a second proposed golf ball having a second outer spherical shape and a multi-layered construction different from the multi-layered construction of the first proposed golf ball; determining a second specific gravity of the second proposed golf ball; designing a second test golf ball having the second outer spherical shape and a one-piece construction; selecting a second material that provides the second test golf ball with a specific gravity substantially equal to the specific gravity of the second proposed golf ball; forming a plurality of second monolithic golf ball blanks from the selected second material to provide an inventory of second monolithic golf ball blanks, each of the second monolithic golf ball blanks having an outer spherical shape substantially equal to the second outer spherical shape of the second proposed golf ball; designing a third dimple design; selecting to which of the first proposed golf ball and the second proposed golf ball to apply the third dimple design; selecting, from the inventories of first and second monolithic golf ball blanks, a first monolithic golf ball blank if the first proposed golf ball is selected and selecting from the inventory a second monolithic golf ball blank if the second proposed golf ball is selected; forming the third dimple design into the selected monolithic golf ball blank to form a third test golf ball; and testing the third test golf ball.
Another aspect provides another method for evaluating golf ball designs. A plurality of proposed golf balls may be designed, each proposed golf ball having a multi-layered construction, an outer spherical shape, and an outer spherical surface. For each proposed golf ball, a proposed design mass of the proposed golf ball may be determined, assuming the outer spherical surface to be smooth. For each proposed golf ball, an average total dimple volume may be designated. For each proposed golf ball, a material may be selected that, when formed into a monolithic test golf ball having the outer spherical shape of the proposed golf ball with a smooth outer spherical surface, weighs the sum of the proposed design mass and the mass of a volume of the material equal to the average total dimple volume. For each proposed golf ball, a plurality of monolithic golf ball blanks may be formed from the selected material, to provide an inventory of monolithic golf ball blanks for each proposed golf ball. A dimple design may be designed. A proposed golf ball to which the dimple design is to be applied may be selected. A monolithic golf ball blank that corresponds to the selected proposed golf ball may be retrieved from the inventory. The dimple design may be formed into the retrieved blank to form a monolithic test golf ball. The monolithic test golf ball may then be tested.
In another aspect, the plurality of proposed golf balls may comprise a first proposed golf ball having a two-piece inner construction and a second proposed golf ball having a three-piece inner construction.
In another aspect, a test golf ball fabrication apparatus may automatically execute, without human intervention, the retrieval from the inventory of the blank that corresponds to the selected proposed golf ball and the formation of the dimple design into the retrieved blank.
In another aspect, the average total dimple volume may comprise 0.75 to 1.3% of an entire volume of the each proposed golf ball without dimples.
In another aspect, the average total dimple volume may comprise a first average total dimple volume, the material may comprise a first material, the plurality of monolithic golf ball blanks may comprise a plurality of first monolithic golf ball blanks corresponding to the first average total dimple volume, the dimple design may comprise a first dimple design, and the method may further comprise designating, for each proposed golf ball, a second average total dimple volume; selecting, for each proposed golf ball, a second material that, when formed into a monolithic test golf ball having the outer spherical shape of the proposed golf ball with a smooth outer spherical surface, weighs the sum of the proposed design mass and the mass of a volume of the material equal to the second average total dimple volume; forming, for each proposed golf ball, a plurality of second monolithic golf ball blanks from the selected second material, to provide an inventory of second monolithic blanks for each proposed golf ball; designing a second dimple design having a total dimple volume; selecting a second proposed golf ball to which the second dimple design is to be applied; retrieving a first monolithic golf ball blank corresponding to the second proposed golf ball if the total dimple volume of the second dimple design is closer in value to the first average total dimple volume than the second average total dimple volume; retrieving a second monolithic golf ball blank corresponding to the second proposed golf ball if the total dimple volume of the second dimple design is closer in value to the second average total dimple volume than the first average total dimple volume; forming the second dimple design into the retrieved first or second monolithic golf ball blank to form a second monolithic test golf ball; and testing the second monolithic test golf ball.
Another aspect provides another method for evaluating golf ball designs. A plurality of proposed golf balls may be designed, each proposed golf ball having a multi-layered construction, an outer spherical shape, and an outer spherical surface. For each proposed golf ball, an undimpled mass of the proposed golf ball may be determined, assuming the outer spherical surface to be smooth. For each proposed golf ball, a material may be selected that, when formed into a monolithic test golf ball having the outer spherical shape of the proposed golf ball with a smooth outer spherical surface, weighs the undimpled mass. For each proposed golf ball, a plurality of monolithic golf ball blanks may be formed from the selected material, to provide an inventory of monolithic golf ball blanks for each proposed golf ball. A dimple design may be designed. A proposed golf ball to which the dimple design is to be applied may be selected. A monolithic golf ball blank that corresponds to the selected proposed golf ball may be retrieved from the inventory. The dimple design may be formed into the retrieved blank to form a monolithic test golf ball. The monolithic test golf ball may then be tested.
In another aspect, the plurality of proposed golf balls may comprise a first proposed golf ball having a two-piece inner construction and a second proposed golf ball having a three-piece inner construction.
Another aspect provides a system for evaluating a golf ball design, which may comprise a computer golf ball design apparatus, a test golf ball fabrication apparatus, and a testing apparatus. The computer golf ball design apparatus may be programmed to receive instructions designating a proposed golf ball having a size and dimple design and a multi-layered construction, the proposed golf ball comprising the golf ball design, determine a specific gravity of the proposed golf ball, and select a material for a monolithic test golf ball having substantially the same size and dimple pattern as the proposed golf ball, wherein the material provides the monolithic test golf ball with a specific gravity substantially equal to the specific gravity of the proposed golf ball. The test golf ball fabrication apparatus may be configured to form the selected material monolithically into the size and dimple design of the proposed golf ball to form the monolithic test golf ball. The testing apparatus may be configured to test the monolithic test golf ball to evaluate the golf ball design.
In another aspect, the test golf ball fabrication apparatus may comprise one of an injection molding machine and an injection press.
In another aspect, the test golf ball fabrication apparatus may comprise a milling machine that mills the monolithic test golf ball from a monolithic block of the selected material.
In another aspect, the testing apparatus may comprise an indoor testing range.
Other systems, methods, features and advantages of the invention will be, or will become, apparent to one of ordinary skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages included within this description and this summary, be within the scope of the invention, and be protected by the following claims.
The invention can be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like reference numerals designate corresponding parts throughout the different views.
Embodiments provide systems and methods for quickly evaluating a golf ball design using rapid prototyping techniques. The prototyping techniques may involve forming a one-piece or multi-piece test golf ball having substantially the same dimple design and specific gravity as a proposed multi-layered golf ball. The prototype test golf ball may be performance-tested (e.g., aerodynamic testing) to evaluate the proposed multi-layered golf ball.
In embodiments, a fast prototyping technique may fabricate a test golf ball from a material (e.g., plastic) having a specific gravity matching that of the desired playing ball design. The test golf ball may be a one-piece or multi-piece sample, preferably durable enough to withstand fifteen impacts. The impacts may be impacts by a golf club swung by a person or machine, or may be simulated impacts of a golf club using a substitute object, such as a metal plate. Any type of material may be used to achieve an appropriate specific gravity. Preferable base materials include acrylonitrile-butadiene-styrene plastic (ABS) and polyoxymethylene plastic (e.g., the product DELRIN™, manufactured by E. I. du Pont de Nemours and Company of Wilmington, Del.) because they are relatively easy to machine. Base materials may be doped to provide a desired specific gravity.
Test golf balls that mimic the specific gravity of a final design enable early aerodynamic testing during the prototyping stage. By making the specific gravity the same or substantially the same as that of the desired final golf ball design, golf ball designers may quickly obtain estimates for the coefficient of lift (CL and the coefficient of drag (CD), as well as other aspects of golf ball and dimple performance such as velocity, spin rate, carry distance, overall distance, and flight time.
In enabling early testing of new dimple patterns, the rapid prototyping techniques may avoid the costly delays involved in the traditional approaches to golf ball design evaluation, which typically require production of a mold and actual manufacturing of the proposed golf ball design.
In designing the proposed golf ball, a designer may use a computer design apparatus, such as apparatus 202 shown in
After designing the proposed golf ball, method 100 may continue in step 104 by determining the specific gravity of the proposed golf ball. The term “specific gravity” as used herein refers to the ratio of the density of a material to the density of water at a specified temperature and pressure, such as 3.98 degrees Celsius and 1 atmosphere. Density is mass divided by volume. The specific gravity may be found by considering all of the components of the proposed golf ball (e.g., the different layers), and the volume and material of each of the components. By considering all of the components, an overall specific gravity for the proposed golf ball may be determined. In embodiments, a designer may use a computer design apparatus, such as computer design apparatus 202 of
Once the specific gravity of the proposed golf ball has been determined, method 100 may continue in step 106 by selecting a material for a test golf ball that will mimic the specific gravity of the proposed golf ball, when the material is formed into a test golf ball having substantially the same size and dimple pattern as the proposed golf ball, but having a predetermined inner construction differing from the inner construction of the proposed golf ball. In other words, step 106 may include selecting a material for a test golf ball that provides the test golf ball with a specific gravity substantially equal to the specific gravity of the proposed golf ball, when the material is formed into a test golf ball having substantially the same size and dimple pattern as the proposed golf ball, but having a predetermined inner construction differing from the inner construction of the proposed golf ball. In one embodiment, the selected material may provide a test golf ball having substantially the same mass as the mass of the proposed golf ball.
The predetermined inner construction of the test golf ball may facilitate rapid, inexpensive manufacturing of the test golf ball. Any suitable construction may be used, including solid, hollow, one-piece, multi-piece, single layer, and multiple layers. In one embodiment, the predetermined inner construction may be a solid one-piece, or monolithic, construction. The terms “monolithic” and “monolithically” as used herein refer to the concept of a one-piece structure formed from a single material (which may be a material mixture, as described below).
In another embodiment, the predetermined inner construction may be a two-piece construction in which two solid hemispherical portions are joined to form a substantially solid test golf ball. The solid hemispherical portions may be joined, for example, by an adhesive, by welding the portions together, by a mechanical connection, or by some combination thereof.
In one implementation, two solid hemispherical portions may be joined at their interior faces.
In another implementation, two solid hemispherical portions may be joined by a dowel joint, in which a dowel is glued inside aligned opposing holes in the two portions.
In another embodiment, the predetermined construction may be a two-piece construction in which two hollow hemispherical portions are joined to form a hollow test golf ball. The hollow hemispherical portions may be joined, for example, by an adhesive, by welding the portions together, by a mechanical connection, or by combinations thereof.
Any suitable material may be used to form a test golf ball. Preferred embodiments may use materials that may be conveniently mixed with other materials to adjust specific gravity and that may be easily manufactured into the predetermined test golf ball construction. For example, ABS or polyoxymethylene plastic may be used. Additives may be mixed with a base material to achieve a desired specific gravity. A designer may use a computer design apparatus, such as apparatus 202 of
Referring again to
In embodiments using a one-piece test golf ball construction, the test golf ball may be molded as one piece, for example, by injection molding. In other embodiments using a one-piece test golf ball construction, the test golf ball may be machined (e.g., milled) out of a solid block of the selected material using a test golf ball manufacturing apparatus 204. In these machining embodiments, apparatus 204 may be, for example, a milling machine that is manually operated, mechanically automated, or digitally automated via computer numerical control (CNC). The test golf ball may be formed (e.g., by injection molding into a monolithic piece or by machining a solid block) directly into the outer form of the proposed golf ball, including the desired dimple design. Alternatively, a golf ball blank may first be formed (e.g., by injection molding a monolithic piece or by machining a solid block), with the golf ball blank being substantially equal in size and shape to the size and shape of the proposed golf ball and having a smooth outer surface (i.e., no dimple pattern). Subsequently, that golf ball blank may be further processed to form the dimple design into the outer surface of the golf ball blank. For example, the dimple design may be formed by mechanical machining (e.g., milling), compression molding, stamping, electro-discharge machining (“EDM”), chemical etching, hobbing, or combinations thereof.
In embodiments using a multi-piece test golf ball construction, the individual pieces of a test golf ball may be molded or may be machined (e.g., milled) out of a solid block of the selected material using a test golf ball manufacturing apparatus 204. In machining embodiments, apparatus 204 may be, for example, a milling machine that is manually operated, mechanically automated, or digitally automated via computer numerical control (CNC). The pieces of the test golf ball may be formed (e.g., by machining or molding) directly into portions of the outer form of the proposed golf ball, including the desired dimple design. Alternatively, the pieces of the test golf ball may first be formed into portions of a golf ball blank that when assembled are substantially equal in size and shape to the size and shape of the proposed golf ball and having a smooth outer surface (i.e., no dimple pattern). Subsequently, with the different pieces assembled into a golf ball blank, the blank may be further processed to form the dimple design into the outer surface of the golf ball blank. For example, the dimple design may be formed by mechanical machining (e.g., milling), compression molding, stamping, electro-discharge machining (“EDM”), chemical etching, hobbing, or combinations thereof.
Embodiments using a one-piece or multi-piece golf ball blank may include provisions for aligning a dimple design applied to a golf ball blank. In embodiments, a test golf ball may be manufactured from a golf ball blank that includes indexing tabs for further manufacturing, for example, of the dimple pattern. After forming dimples into a golf ball blank according to a desired specification, the indexing tabs may be cut, ground, and/or buffed off.
In one embodiment, a golf ball blank may have index tabs positioned at the six X-, Y-, and Z-axis points on the surface of the spherical golf ball blank, assuming the center of the ball to coincide with the origin of the Cartesian coordinate system. For example,
In other embodiments, a test golf ball may be formed by injecting the selected material into a mold to form the entire test golf ball or portions of the test golf ball, such as two hemispherical portions. In these embodiments, test golf ball manufacturing apparatus 204 of
In another embodiment, multiple molds may be formed corresponding to the size, shape, and dimple design of portions of the proposed golf ball, such as hemispherical portions of the proposed golf ball. The selected material may then be injected in liquid form into the multiple molds. The material may then be cooled and solidified into the size, shape, and dimple design of the portions of the proposed golf ball. The portions may then be assembled into the test golf ball. Alternatively, instead of multiple molds, a single mold may be used where the portions are identical.
Referring again to
Following testing, a designer may conclude that the proposed golf ball is deficient in one or more performance characteristics. In that case, method 100 may be repeated for a new proposed golf ball. Method 100 may be repeated as many times as necessary to determine an acceptable proposed golf ball design.
Method 100 of
Further embodiments may include provisions for rapidly prototyping and testing individual dimple designs on a predetermined golf ball inner construction. In this situation, a designer may have settled upon an inner multi-layered construction and may desire to experiment with different dimple designs for that particular inner multi-layered construction. Accordingly, embodiments enable a quick formation of a proposed dimple design onto a test golf ball blank for testing purposes.
After completing one or more proposed golf ball inner construction designs, process 300 may continue by fabricating a plurality of test golf ball blanks for each design. Fabricating the blanks may involve determining a specific gravity of a proposed golf ball inner construction, selecting a material that will mimic the specific gravity of the proposed golf ball when formed into a test golf ball blank having a predetermined construction, and forming the blank from the selected material, as discussed above in reference to steps 104-108 of
In one embodiment using a one-piece test golf ball construction, as shown in
With a plurality of blocks formed for each design, method 300 may continue by machining each block into the size and outer spherical shape of the each design, without dimples.
Following machining, a plurality of undimpled test golf ball blanks may be obtained for each of the proposed golf ball inner constructions. For example, as shown in
As an alternative, the process 300 of
In another embodiment, instead of machining the test golf ball blanks from blocks of selected material (as shown in
In other embodiments, instead of injection molding an entire test golf ball blank, the process 300 may injection mold portions of a test golf ball blank, such as two hemispherical portions. In this alternative two-piece construction embodiment, the test golf ball blank portions formed at stages 314 and 316 may then be joined together to form the individual two-piece test golf ball blanks 318 and 320. The portions may be joined by the methods described above, such as those discussed in reference to
Having amassed an inventory of test golf ball blanks, a golf ball designer may then create and quickly prototype various dimple designs. A designer may create a dimple design and then apply it to different proposed golf ball inner constructions, choosing the corresponding test golf ball blank from the inventory for each of the proposed designs. A designer may also create a plurality of dimple designs for a particular proposed golf ball inner construction, retrieve a golf ball blank corresponding to the proposed inner construction design for each of the proposed dimple designs, and fabricate a test golf ball for each of the proposed dimple designs. A designer may manufacture the test golf balls for the proposed inner construction designs in a serial manner, a parallel manner, or a combination of those approaches.
With the proposed dimple design 402 completed, a user may then retrieve from the inventory 322 a golf ball blank corresponding to the proposed golf ball inner construction to which the dimple design 402 was applied. For instance, in the example illustrated in
With the appropriate golf ball blank 408 retrieved, the rapid dimple design prototyping process 400 may continue in a dimple fabrication stage 406, forming the dimple design into the outer surface of the retrieved golf ball blank 408, as represented in
With the fabrication stage 406 completed, a test golf ball 410 may be provided, which has a specific gravity substantially the same as the specific gravity of the proposed golf ball inner construction, such that the mass of the test golf ball 410 is substantially the same as the computed mass of the proposed golf ball having the proposed inner construction and dimple design. Test golf ball 410 may then be performance-tested to evaluate the proposed golf ball.
As represented in
To further quicken the dimple design prototyping process 400, embodiments of process 400 may also be partially or fully automated. For example, a golf ball designer may electronically send a completed proposed inner construction and dimple design to a computerized test golf ball fabrication apparatus that, without human intervention, automatically retrieves from an inventory a golf ball blank corresponding to the predetermined inner construction, transports the retrieved golf ball blank to a dimple forming apparatus, and controls the dimple forming apparatus to form the predetermined dimple design into the surface of the blank. The computerized test golf ball fabrication apparatus may then output a completed test golf ball.
These rapid prototyping approaches may also be employed in the process 100 described above.
In establishing an inventory of golf ball blanks as exemplified in
Thus, in one embodiment, an average total dimple volume may be factored in when determining the specific gravity of a proposed golf ball design. For example, after creating a proposed golf ball inner construction having a smooth outer surface (i.e., no dimples), an average total dimple volume may be deducted from the outer layer or outer layers of the proposed inner construction design to compute a dimple-adjusted specific gravity. That dimple-adjusted specific gravity may then be used to select a material for fabrication of the test golf ball blank. The average total dimple volume may be an average of the volumes of dimple designs typically considered in designing golf balls, and may be expressed in terms of a percent dimple volume. A percent dimple volume may be, for example, 0.75 to 1.3%, and defined as the sum of volumes of dimple spaces each defined below a plane circumscribed by the upper edges of the dimples divided by the entire volume of the outer smooth surface of proposed inner construction design without dimples (e.g., a phantom sphere given on the assumption that no dimples are on the golf ball surface).
In considering average total dimple volume in this embodiment, a method for evaluating golf ball designs may comprise designing a plurality of proposed golf balls, each proposed golf ball having an inner construction, an outer spherical shape, and an outer spherical surface. For each proposed golf ball, a proposed design mass of the proposed golf ball may be determined, assuming the outer spherical surface to be smooth. For each proposed golf ball, an average total dimple volume may be designated, and then a material may be selected that, when formed into the predetermined test golf ball construction having the outer spherical shape of the proposed golf ball with a smooth outer spherical surface, weighs the sum of the proposed design mass and the mass of a volume of the material equal to the average total dimple volume. For each proposed golf ball, a plurality of golf ball blanks may be formed from the selected material, to provide an inventory of blanks for each proposed golf ball. A dimple design may then be designed and a proposed golf ball to which the dimple design is to be applied may be selected. A blank corresponding to the selected proposed golf ball may then be retrieved from the inventory. The dimple design may then be formed into the retrieved blank to form a test golf ball, which may then be tested.
In another embodiment, to provide more accuracy over the average total dimple volume method described above, test golf ball blanks may be prefabricated for different dimple volumes, with each blank formed from a material appropriate for its designated dimple volume. The test golf ball blanks may be marked to indicate the dimple volume for which they have been designed, and may be segregated and stored according to dimple volume. In testing and evaluating a particular dimple design having a particular dimple volume, a golf ball designer may then retrieve a blank that has been prefabricated for that particular dimple volume.
In another embodiment, the dimple volume may be ignored in computing the specific gravity of a proposed golf ball inner construction. In other words, the specific gravity of a proposed golf ball inner construction may be computed under the assumption that the outer surface is smooth, with no dimples. A test golf ball blank material may then be chosen based on the specific gravity of the undimpled proposed golf ball inner construction design. In this situation, the final mass of a test golf ball may be slightly different from the computed mass of the proposed golf ball with dimples, due to the difference between the specific gravity of the blank material and the specific gravity of the outer layer or outer layers of the proposed golf ball design in which the dimples are formed. However, this slight difference may be acceptable for prototyping purposes, especially in early evaluations of a proposed dimple design.
In this embodiment, a method for evaluating golf ball designs may comprise designing a plurality of proposed golf balls, each proposed golf ball having an inner construction, an outer spherical shape, and an outer spherical surface. For each proposed golf ball, an undimpled mass of the proposed golf ball may be determined, assuming the outer spherical surface to be smooth. For each proposed golf ball, a material may be selected that, when formed into the predetermined test golf ball construction having the outer spherical shape of the proposed golf ball with a smooth outer spherical surface, weighs the undimpled mass. For each proposed golf ball, a plurality of golf ball blanks may be formed from the selected material, to provide an inventory of blanks for each proposed golf ball. A dimple design may then be designed, and a proposed golf ball to which the dimple design is to be applied may be selected. A blank corresponding to the selected proposed golf ball may be retrieved from the inventory and the dimple design may be formed into the retrieved blank to form a test golf ball. The test golf ball may then be tested to evaluate the golf ball design.
In some embodiments, a structural design of a test golf ball may allow adjustments in mass to provide a test golf ball having a specific gravity as close as possible to the specific gravity of the actual golf ball. In one embodiment, with a multi-piece test golf ball, material may be added or removed from interior portions of the separate pieces. For example, in a test golf ball having two hemispherical portions, material may be added or removed from an interior face of the hemispherical portions, such as the interior faces 601 and 605 of
In some embodiments, a structure of test golf ball may be adjusted to mimic flight or spin characteristics of a proposed golf ball. For example, to mimic a moment of inertia of a proposed golf ball, a test golf ball may be designed with two hollow hemispherical portions, which, in comparison to a monolithic test golf ball, may better approximate the outwardly distributed mass typical of multi-layered proposed golf ball designs.
Examples of the invention are given below for purposes of illustration and are not intended to limit the invention in any way. The examples describe embodiments of test golf balls that were actually manufactured and performance-tested, to evaluate aspects of manufacturability and durability, and to compare their performance characteristics to the actual golf balls after which the test golf balls were modeled. In the context of the invention, the actual golf balls represented the proposed golf ball designs. The examples demonstrated that the test golf balls may adequately mimic the performance of actual (or proposed) golf balls in the performance characteristics of drag and lift.
In this example, two substantially solid multi-piece test golf balls were manufactured based on the design of an actual golf ball and subjected to aerodynamic testing at an indoor test range. Each multi-piece test golf ball was made of nylon and was constructed from two solid hemispherical portions attached together by a glued dowel, in a manner similar to that described above in reference to
The type of nylon material was chosen to achieve a mass of the assembled test golf ball approximating the mass of the actual golf ball, taking into account such factors as the use of the dowel, the glue, and the holes in the hemispherical portions. A nylon material was chosen that provided a mass slightly higher than the mass of the actual golf ball so that the mass of the test golf ball could be fine-tuned by removing small amounts of material from the interior faces of the hemispherical portions, such as the interior faces 614 and 616 shown in the example of
The test golf balls were shot through an indoor test range at 110 mph with 1740 rpm, traveling approximately 70 feet before impact. The test golf balls were shot in a pole-over-pole orientation (“pole orientation”) and a poles-horizontal orientation (“seam orientation”). The lift and drag of the test golf balls were measured and computed. The actual golf balls were subjected to the same tests, measurements, and computations. The lift and drag characteristics were then compared between the test golf balls and the actual golf balls.
Both the coefficient of drag (CD) and also the coefficient of lift (CL) may be used to quantify the force imparted to a ball in flight, and may be dependent on factors such as air density, air viscosity, ball speed, and spin rate. The influence of all of those factors may be embodied in two dimensionless parameters: Spin Ratio (SR) and Reynolds Number (Re). Spin Ratio is the rotational surface speed of the ball divided by ball speed. Reynolds Number quantifies the ratio of inertial to viscous forces acting on the golf ball moving through air.
In this example, the coefficients of drag and coefficients of lift were determined for a given Spin Ratio of approximately 0.08 and a given Reynolds Number of approximately 1.30, using indoor test range methods known in the art. One skilled in the art of golf ball aerodynamics testing would readily understand the determination of lift and drag coefficients using an indoor test range, or alternatively a wind tunnel.
Two sets of tests were conducted, one for pole orientation and one for seam orientation. In each set of tests, six test golf balls and six actual golf balls were shot and evaluated. Table 1 below lists the CD and CL results of the six test golf balls shot through the indoor test range in a pole orientation, with the average of the six shots listed at the bottom of the table:
Table 2 below lists the CD and CL results of the six actual golf balls shot through the indoor test range in a pole orientation, with the average of the six shots listed at the bottom of the table:
Table 3 below lists the CD and CL results of the six test golf balls shot through the indoor test range in a seam orientation, with the average of the six shots listed at the bottom of the table:
Table 4 below lists the CD and CL results of the six actual golf balls shot through the indoor test range in a seam orientation, with the average of the six tests listed at the bottom of the table:
The adjoining bars compare the CD values for the test golf balls and the actual golf balls. Similarly,
Table 5 below indicates the averages of the tests, the standard deviations, and the variances of the test golf ball data relative to the actual test golf ball data:
As shown in the tables and graphs, the variance of CD and CL data of the test golf balls is somewhat higher than that of the actual test golf balls. Nevertheless, the test golf ball data is reasonable and comparable. In comparison to the actual golf ball, the test golf ball varied in coefficient of drag CD approximately 5% for the pole orientation and approximately 4% for the seam orientation. The test golf ball varied in coefficient of lift CL approximately 3% for pole orientation and approximately 13% for seam orientation. Considering the USGA tolerance of 5%, these results demonstrate that the two-piece nylon test golf balls may be suitable for aerodynamic testing, yielding informative data for the design and testing of proposed golf ball designs. In addition, the test golf balls showed good durability during shot testing, exhibiting only minor signs of separation between the two hemispherical portions of the test golf balls.
In this example, two hollow multi-piece test golf balls were manufactured based on the design of an actual golf ball and subjected to aerodynamic testing at an indoor test range. Each multi-piece test golf ball was made of polyoxylmethylene (POM) and was constructed from two hollow hemispherical portions, the edges of which were glued together in a manner similar to that described above in reference to
The type of POM material was chosen to achieve a mass of the assembled test golf ball approximating the mass of the actual golf ball, taking into account such factors as the use of the glue and the wall thickness of the hollow hemispherical portions. A POM material was chosen that provided a mass slightly higher than the mass of the actual golf ball so that the mass of the test golf ball could be fine-tuned by removing small amounts of material from the interior faces of the hemispherical portions, such as the interior faces 674 and 676 shown in the example of
The test golf balls were shot through an indoor test range at 110 mph with 1740 rpm, traveling approximately 70 feet before impact. The test golf balls were shot in a pole orientation. The lift and drag of the test golf balls were measured and computed. The actual golf balls were subjected to the same tests, measurements, and computations. The lift and drag characteristics were then compared between the test golf balls and the actual golf balls.
In this example, the coefficients of drag and coefficients of lift were determined for a given Spin Ratio of approximately 0.08 and a given Reynolds Number of approximately 1.30, using indoor test range methods known in the art. One skilled in the art of golf ball aerodynamics testing would readily understand the determination of lift and drag coefficients using an indoor test range, or alternatively a wind tunnel.
One set of tests was conducted, which include three shots of the test golf balls and six shots of the actual golf balls. The shots of the test golf balls were limited due to changes in the structure of the test golf balls caused by the impacts of the testing. Table 6 below lists the CD and CL results of the three shots of the test golf balls through the indoor test range in a pole orientation, with the average of the three shots listed at the bottom of the table:
Table 7 below lists the CD and CL results of the six shots of the actual golf balls through the indoor test range in a pole orientation, with the average of the six shots listed at the bottom of the table:
Table 8 below indicates the averages of the tests, the standard deviations, and the variances of the test golf ball data relative to the actual test golf ball data:
As shown in the tables and graphs, the test golf balls exhibited slightly lower lift and drag coefficients in comparison to the actual golf balls. The error was linear. In comparison to the actual golf ball, the test golf ball varied in coefficient of drag CD approximately 3% and varied in coefficient of lift CL approximately 5%. Considering the USGA tolerance of 5%, these results demonstrate that the two-piece POM test golf balls may be suitable for aerodynamic testing, yielding informative data for the design and testing of proposed golf ball designs.
The foregoing disclosure of embodiments of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many variations and modifications of the embodiments described herein will be apparent to one of ordinary skill in the art in light of the above disclosure. The scope of the invention is to be defined only by the claims and their equivalents.
Further, in describing representative embodiments, the specification may have presented a method and/or process as a particular sequence of steps. However, to the extent that the method or process does not rely on the particular order of steps set forth herein, the method or process should not be limited to the particular sequence of steps described. As one of ordinary skill in the art would appreciate, other sequences of steps may be possible. Therefore, the particular order of the steps set forth in the specification should not be construed as limitations on the claims. In addition, the claims directed to a method and/or process should not be limited to the performance of their steps in the order written, and one skilled in the art can readily appreciate that the sequences may be varied and still remain within the spirit and scope of the present invention.
