This present technology generally relates to systems, devices, and methods related to golf clubs, and more specifically to metal wood golf clubs including improved crown constructions as well as improved variable face thickness profiles.
In the competitive industry of golf club design, distance and accuracy are two of the most important performance factors that help define the desirability of a metal wood type golf club. Although some may argue that the look, feel, and sound of a golf club may influence their opinion of a golf club; there is no arguing that the performance factors play a major role in determining the desirability of a golf club. The performance factors of maximizing distance while maintaining accuracy becomes even more prevalent in a metal wood type golf club head. Unlike iron type golf club heads where accuracy of a golf shot clearly trumps the distance benefits gained by any individual golf club, metal wood type golf club heads are designed to allow a golfer to hit the golf ball as far as possible and as straight as possible.
In order to maximize distance while maintaining accuracy of a metal wood type golf club head, metal wood type golf clubs have been designed with the objective of maximizing the distance of a golf ball struck by a golf club head close to the geometric center of the golf club head. This geometric center of the golf club head, due to the inherent laws of physics, may generally produce a golf shot that maximizes the distance by reducing the energy loss during impact between the golf ball and the golf club head. In order to quantify this value, the United States Golf Association (USGA), in conjunction with the golfing industry, have come up with various methods such as the calculation the Coefficient of Restitution (COR) or the calculation of the Characteristic Time (CT) as ways to quantify the rebounding characteristic of a golf ball after it impacts a golf club head.
U.S. Pat. No. 6,390,933 to Galloway et al. ('933 Patent) discusses one of the methods to increase the COR of a golf club head by disclosing a golf club head having a coefficient of restitution greater than 0.845 and a durability to withstand 2000 impacts with a golf ball at 110 miles per hour, wherein the club head may be composed of three pieces, a face, a sole, and a crown. More specifically, the '933 Patent discloses a golf club head that may be composed of a titanium material, having a volume in the range of 175 cubic centimeters to 400 cubic centimeters, a weight in the range of 165 grams to 300 grams, and a striking plate surface area in the range of 4.00 square inches to 7.50 square inches.
Focusing on accuracy instead of distance, U.S. Patent Publication No. 2004/0116202 to Lin ('202 Patent Publication), discusses a method to increase the accuracy of a golf club head by disclosing a golf club head having a plurality of holes around the periphery of the club head, so that when the club head hits the golf ball, most of the vibration waves and sound waves generated are dispersed out of these holes thus improving accuracy of the direction of the striking golf ball.
However, upon closer examination, we can see that developments in maximizing distance while maintaining accuracy of a metal wood type golf club head are premised upon the fact that the golfer be capable of hitting the golf ball at the sweet spot. It may be difficult for the average golfer to consistently strike a golf ball in the sweet spot. Hence, in addition to the performance factors mentioned above, it may also be desirable to optimize the size and location of this sweet spot, so an average golfer may obtain the design benefits of maximizing the distance and accuracy of the golf club head.
The systems, methods, and devices described herein have innovative aspects, no single one of which is indispensable or solely responsible for their desirable attributes. Without limiting the scope of the claims, some of the advantageous features will now be summarized.
One aspect of the present technology is the realization that conventional golf clubs do not perform as well for off-center hits. Thus, there exists a need for an improved golf club head construction. The present technology is directed to metalwood golf clubs. The present invention provides ball speed enhancing features, including for example, a locally raised crown peak, and a sole biased variable face thickness profile which improve the off-center performance of the golf club head. As a result, a golfer can strike the golf ball with a portion of the face other than the geometric center of the striking face, and still obtain desirable distance.
One non-limiting embodiment of the present technology includes a metalwood golf club head, comprising: a striking face; a posterior body portion comprising a crown and a sole, wherein said crown is connected to an upper portion of said striking face and said sole is connected to a lower portion of said striking face; a hosel located on a heel side of said golf club head; a toe side located opposite said heel side; a coordinate system comprising: an x-axis parallel to a ground plane when said golf club head is grounded upon said ground plane according to the prescribed lie and loft of said golf club head, said x-axis substantially parallel to said striking face, said x-axis extending in a positive direction towards said heel of said golf club head; a y-axis perpendicular to said x-axis, said y-axis perpendicular to said ground plane, said y-axis extending in a positive direction upwards toward said crown; a z-axis perpendicular to said x-axis, said z-axis perpendicular to said y axis, said z-axis parallel to said ground plane, said z-axis extending in a positive direction forwards towards said striking face; wherein said golf club head comprises a golf club head interior, wherein said crown comprises an outer surface, said outer surface opposite said golf club head interior; wherein said crown comprises a crown peak, said crown peak defined as the highest point on said outer surface of said crown when said golf club head is grounded at said prescribed lie and loft; a plurality of points located on said outer surface of said crown, said plurality of points all located along a plane parallel to said y-axis and said x-axis when said golf club head is grounded at said prescribed lie and loft, said plane passing through said crown peak, said plurality of points comprising: a Point A located at said crown peak; a Point B located 10 mm heel-ward from said Point A along an axis parallel to said x-axis; a Point C located 20 mm heel-ward from said Point A along an axis parallel to said x-axis; a Point D located 10 mm toe-ward from said Point A along an axis parallel to said x-axis; a Point E located 20 mm toe-ward from said Point A along an axis parallel to said x-axis; wherein the absolute value of the slope between said Point B and said Point C is greater than or equal to 0.117 and less than or equal to 0.310; and wherein the absolute value of the slope between said Point D and said Point E is greater than or equal to 0.100 and less than or equal to 0.392.
In an additional non-limiting embodiment of the present technology said crown peak is located less than 68 mm above said ground plane, and wherein said absolute value of the slope between said Point B and said Point C is greater than or equal to 0.122 and less than or equal to 0.293, and wherein said absolute value of the slope between said Point D and said Point E is greater than or equal to 0.105 and less than or equal to 0.372.
In an additional non-limiting embodiment of the present technology said absolute value of the slope between said Point B and said Point C is greater than or equal to 0.133 and less than or equal to 0.293, and wherein said absolute value of the slope between said Point D and said Point E is greater than or equal to 0.114 and less than or equal to 0.372.
In an additional non-limiting embodiment of the present technology said absolute value of the slope between said Point B and said Point C is greater than or equal to 0.122 and less than or equal to 0.261, and wherein said absolute value of the slope between said Point D and said Point E is greater than or equal to 0.105 and less than or equal to 0.330.
In an additional non-limiting embodiment of the present technology said absolute value of the slope between said Point A and said Point B is greater than or equal to 0.028 and less than or equal to 0.193, and wherein said absolute value of the slope between said Point A and said Point D is greater than or equal to 0.046 and less than or equal to 0.148.
In an additional non-limiting embodiment of the present technology said absolute value of the slope between said Point A and said Point B is greater than or equal to 0.030 and less than or equal to 0.183, and wherein said absolute value of the slope between said Point A and said Point D is greater than or equal to 0.048 and less than or equal to 0.140.
An additional non-limiting embodiment of the present technology includes a variable face thickness profile on an inside of said striking face, said variable face thickness profile comprising a thick central portion surrounded by a transition portion, said transition portion surrounded by a thin perimeter portion of the striking face, wherein a second plane is parallel to said y-axis and said z-axis passes through a center of said thick central portion, wherein a third plane is parallel to said striking face at geometric face center, wherein a measurement axis is formed at the intersection of said second plane and said third plane, wherein a distance D3 represents the distance measured between the top of said thin perimeter portion to the top of said thick central portion along said measurement axis and a distance D4 represents the distance measured between the bottom of said thin perimeter portion to the bottom of said thick central portion along said measurement axis, wherein a ratio of said distance D3 over said Distance D4 is greater than 1.05.
In an additional non-limiting embodiment of the present technology said ratio of said distance D3 over said Distance D4 is greater than 1.1 and less than 1.5.
An additional non-limiting embodiment of the present technology includes metalwood golf club head, comprising: a striking face; a posterior body portion comprising a crown and a sole, wherein said crown is connected to an upper portion of said striking face and said sole is connected to a lower portion of said striking face; a hosel located on a heel side of said golf club head; a toe side located opposite said heel side; a coordinate system comprising: an x-axis parallel to a ground plane when said golf club head is grounded upon said ground plane according to the prescribed lie and loft of said golf club head, said x-axis substantially parallel to said striking face, said x-axis extending in a positive direction towards said heel of said golf club head; a y-axis perpendicular to said x-axis, said y-axis perpendicular to said ground plane, said y-axis extending in a positive direction upwards toward said crown; a z-axis perpendicular to said x-axis, said z-axis perpendicular to said y axis, said z-axis parallel to said ground plane, said z-axis extending in a positive direction forwards towards said striking face; wherein said golf club head comprises a golf club head interior, wherein said crown comprises an outer surface, said outer surface opposite said golf club head interior; wherein said crown comprises a crown peak, said crown peak defined as the highest point on said outer surface of said crown when said golf club head is grounded at said prescribed lie and loft; a crown peak plane parallel to said ground plane, said crown peak plane passing through said crown peak; a crown cutoff plane parallel to said crown peak plane, said crown cutoff plane offset downwards towards said ground plane 5 mm along said y-axis from said crown peak plane; an upper crown portion located above said crown cutoff plane and defined by said crown cutoff plane and said outer surface of said crown; wherein a volume of said upper crown portion is greater than 2 cm3 and less than 7 cm3.
In an additional non-limiting embodiment of the present technology said volume of said upper crown portion is greater than 2 cm3 and less than 7 cm3.
In an additional non-limiting embodiment of the present technology said volume of said upper crown portion is greater than 3 cm3 and less than 6 cm3.
In an additional non-limiting embodiment of the present technology said volume of said upper crown portion is greater than 3 cm3 and less than 5 cm3.
In an additional non-limiting embodiment of the present technology said volume of said upper crown portion is greater than 3 cm3 and less than 4 cm3.
An additional non-limiting embodiment of the present technology includes a variable face thickness profile on an inside of said striking face, said variable face thickness profile comprising a thick central portion surrounded by a transition portion, said transition portion surrounded by a thin perimeter portion of the striking face, wherein a second plane is parallel to said y-axis and said z-axis passes through a center of said thick central portion, wherein a third plane is parallel to said striking face at geometric face center, wherein a measurement axis is formed at the intersection of said second plane and said third plane, wherein a distance D3 represents the distance measured between the top of said thin perimeter portion to the top of said thick central portion along said measurement axis and a distance D4 represents the distance measured between the bottom of said thin perimeter portion to the bottom of said thick central portion along said measurement axis, wherein a ratio of said distance D3 over said Distance D4 is greater than 1.05.
In an additional non-limiting embodiment of the present technology said ratio of said distance D3 over said Distance D4 is greater than 1.1 and less than 1.5.
An additional non-limiting embodiment of the present technology includes a metalwood golf club head, comprising: a striking face; a posterior body portion comprising a crown and a sole, wherein said crown is connected to an upper portion of said striking face and said sole is connected to a lower portion of said striking face; a hosel located on a heel side of said golf club head; a toe side located opposite said heel side; a coordinate system comprising: an x-axis parallel to a ground plane when said golf club head is grounded upon said ground plane according to the prescribed lie and loft of said golf club head, said x-axis substantially parallel to said striking face, said x-axis extending in a positive direction towards said heel of said golf club head; a y-axis perpendicular to said x-axis, said y-axis perpendicular to said ground plane, said y-axis extending in a positive direction upwards toward said crown; a z-axis perpendicular to said x-axis, said z-axis perpendicular to said y-axis, said z-axis parallel to said ground plane, said z-axis extending in a positive direction forwards towards said striking face; wherein said golf club head comprises a golf club head interior, wherein said crown comprises an outer surface, said outer surface opposite said golf club head interior; wherein said crown comprises a crown peak, said crown peak defined as the highest point on said outer surface of said crown when said golf club head is grounded at said prescribed lie and loft; a plurality of points located on said outer surface of said crown, said plurality of points all located along a plane parallel to said y-axis and said x-axis when said golf club head is grounded at said prescribed lie and loft, said plane passing through said crown peak, said plurality of points comprising: a Point A located at said crown peak; a Point B located 10 mm heel-ward from said Point A along an axis parallel to said x-axis; a Point C located 20 mm heel-ward from said Point A along an axis parallel to said x-axis; a Point D located 10 mm toe-ward from said Point A along an axis parallel to said x-axis; a Point E located 20 mm toe-ward from said Point A along an axis parallel to said x-axis; wherein the absolute value of the slope between said Point B and said Point C is greater than or equal to 0.117 and less than or equal to 0.310; wherein the absolute value of the slope between said Point D and said Point E is greater than or equal to 0.100 and less than or equal to 0.392; a crown peak plane parallel to said ground plane, said crown peak plane passing through said crown peak; a crown cutoff plane parallel to said crown peak plane, said crown cutoff plane offset downwards towards said ground plane 5 mm along said y-axis from said crown peak plane; an upper crown portion located above said crown cutoff plane and defined by said crown cutoff plane and said outer surface of said crown; wherein a volume of said upper crown portion is greater than 2 cm3 and less than 7 cm3; and a variable face thickness profile on an inside of said striking face, said variable face thickness profile comprising a thick central portion surrounded by a transition portion, said transition portion surrounded by a thin perimeter portion of the striking face, wherein a second plane is parallel to said y-axis and said z-axis passes through a center of said thick central portion, wherein a third plane is parallel to said striking face at geometric face center, wherein a measurement axis is formed at the intersection of said second plane and said third plane, wherein a distance D3 represents the distance measured between the top of said thin perimeter portion to the top of said thick central portion along said measurement axis and a distance D4 represents the distance measured between the bottom of said thin perimeter portion to the bottom of said thick central portion along said measurement axis, wherein a ratio of said distance D3 over said Distance D4 is greater than 1.05; wherein said sole further comprises a flexure spaced from said striking face, said flexure comprising a front wall, an apex, and a rear wall, wherein said front wall and said rear wall both extend into said golf club head interior, and wherein said front wall and said rear wall are coupled at said apex.
In an additional non-limiting embodiment of the present technology said volume of said upper crown portion is greater than 3 cm3 and less than 5 cm3, and wherein a crown peak depth of said golf club head is at least 26 mm, said crown peak depth measured from a forward most portion of said golf club head to said crown peak along an axis parallel to said z-axis.
In an additional non-limiting embodiment of the present technology said absolute value of the slope between said Point A and said Point B is greater than or equal to 0.030 and less than or equal to 0.183, and wherein said absolute value of the slope between said Point A and said Point D is greater than or equal to 0.048 and less than or equal to 0.140.
In an additional non-limiting embodiment of the present technology said ratio of said distance D3 over said Distance D4 is greater than 1.1 and less than 1.5.
In an additional non-limiting embodiment of the present technology said sole further comprises a flexure spaced from said striking face, said flexure comprising a front wall, an apex, and a rear wall, wherein said front wall and said rear wall both extend into said golf club head interior, and wherein said front wall and said rear wall are coupled at said apex.
The accompanying drawings form a part of the specification and are to be read in conjunction therewith. The illustrated embodiments, however, are merely examples and are not intended to be limiting. Like reference numbers and designations in the various drawings indicate like elements.
In the following detailed description, reference is made to the accompanying drawings, which form a part of the present disclosure. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the Figures, can be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are explicitly contemplated and form part of this disclosure. For example, a system or device may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, such a system or device may be implemented or such a method may be practiced using other structure, functionality, or structure and functionality in addition to or other than one or more of the aspects set forth herein. Alterations and further and further modifications of inventive features illustrated herein, and additional applications of the principles of the inventions as illustrated herein, which would occur to one skilled in the relevant art and having possession of this disclosure, are to be considered within the scope of the invention.
Other than in the operating examples, or unless otherwise expressly specified, all of the numerical ranges, amounts, values and percentages such as those for amounts of materials, moments of inertias, center of gravity locations, loft and draft angles, and others in the following portion of the specification may be read as if prefaced by the word “about” even though the term “about” may not expressly appear with the value, amount, or range. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.
Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Furthermore, when numerical ranges of varying scope are set forth herein, it is contemplated that any combination of these values inclusive of the recited values may be used.
In describing the present technology, the following terminology may have been used: The singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to an item includes reference to one or more items. The term “plurality” refers to two or more of an item. The term “substantially” means that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide. A plurality of items may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same lists solely based on their presentation in a common group without indications to the contrary. Furthermore, where the terms “and” and “or” are used in conjunction with a list of items, they are to be interpreted broadly, in that any one or more of the listed items may be used alone or in combination with other listed items. The term “alternatively” refers to a selection of one of two or more alternatives, and is not intended to limit the selection of only those listed alternative or to only one of the listed alternatives at a time, unless the context clearly indicated otherwise.
Features of the present disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. After considering this discussion, and particularly after reading the section entitled “Detailed Description” one will understand how the illustrated features serve to explain certain principles of the present disclosure.
Embodiments described herein generally relate to systems, devices, and methods related to golf club heads. More specifically, some embodiments relate to metalwood golf clubs including improved crown constructions as well as improved variable face thickness profiles.
The golf club head 100, as depicted in
As illustrated in
Various features of a golf club head 100 can affect the performance characteristics of the golf club head 100 which may include, for example, ball speed after impact at various points on the striking face 106, the size of the sweet spot of the striking face 106, the backspin of the golf ball after impact, etc. Generally, it is a goal of the golf club designer to maximize the size of the sweet spot, or the portion of the striking face which transfers the maximum amount of energy to the golf ball at impact. One advantage of the golf club head 100 described herein is improved performance characteristics provided by a unique construction of the crown 112. The unique construction discussed herein and illustrated in the figures, has a locally raised crown peak 128 compared to a traditional crown. This unique crown construction can be incorporated in a driver as illustrated herein, but can also be incorporated into a fairway or hybrid as well.
Often during testing, ballspeed after impact is measured at various portions of the striking face 106 in addition to the geometric center. The geometric center of the striking face 106 is defined by the center of the impact spot determined by the Impact Location Template outlined in the Procedure for Measuring the Flexibility of a Golf Clubhead, USGA-TPX3004, Revision 1.0.0, May 1, 2008 by the United States Golf Association. One such portion of the striking face can be high center, defined as a 0.25″ above geometric face center. One embodiment of a golf club head 100 including the unique crown construction described herein achieves approximately 0.3% additional ball speed at high center compared to the same driver without the unique crown construction, all while maintaining the highest possible ballspeed at geometric face center allowed by the United States Golf Association. In addition, the golf club head 100 including the unique crown construction herein was able to achieve a high center ballspeed within 99.56% of ballspeed at geometric face center while the same driver without the unique crown construction was only able to achieve a high center ballspeed within 99.28% of ballspeed at geometric face center. In some embodiments, these performance improvements can be a result of added compliance at points above geometric face center on the striking face 106 of the club head 100 due to the unique crown construction described herein. The significance of increased ballspeed off center, at a location such a high center, is increased distance forgiveness for an off center hit. Even if a golfer doesn't hit the ball exactly at geometric face center, the ball will still travel nearly as far as if they had hit the ball at geometric face center.
Table 1 below outlines the offset distances between Points A-E for one embodiment of the golf club head 100 described herein. Distance values are measured in millimeters (mm). The distance values included in Table 1 are utilized throughout the specification and in subsequent tables below when defining slopes and relationships between Points A-E.
Table 2 below outlines the heights of Points A-E to further illustrate one embodiment of the golf club head 100 described herein.
In some embodiments, the golf club head 100 includes a crown peak 128 located less than 68 mm from the ground plane 200. In some embodiments, the golf club head 100 includes a crown peak 128 located less than 66 mm from the ground plane 200.
Table 3 below outlines the slopes between various Points A-E to further illustrate one embodiment of the golf club head 100 described herein. For example, the slope between Point A and Point B, would be calculated by dividing the difference in height between Point A and Point B by the offset distance between Point A and Point B. Each of the slope values are the absolute value of the calculated slope. Thus, whether the heel-most point or toe-most point is further from the ground plane 200, does not affect the value of the slope.
Table 4 below illustrates a range of slopes between Points A-E within which an embodiment of the golf club head 100 could reside.
Table 5 below illustrates a range of slopes between Points A-E within which an embodiment of the golf club head 100 could reside.
Table 6 below illustrates a range of slopes between Points A-E within which an embodiment of the golf club head 100 could reside.
Table 7 below illustrates a range of slopes between Points A-E within which an embodiment of the golf club head 100 could reside.
Table 8 below illustrates a range of slopes between Points A-E within which an embodiment of the golf club head 100 could reside.
In some embodiments, the golf club head 100, as illustrated in
During testing, a golf club head 100 including the unique crown construction and the unique sole biased variable face thickness profile 136 described herein achieves approximately 0.15% additional ball speed at high center compared to the same golf club head without the unique sole biased variable face thickness profile 136 described herein. Additionally, when a golf club head 100 combines the unique crown construction and the unique sole biased variable face thickness profile 136 described herein, the driver achieves approximately 0.45% additional ball speed at high center compared to the same golf club head without the unique crown construction and unique sole biased variable face thickness profile 136 described herein.
Distances D1-D4 are included in
In one embodiment, the ratio of D1 over D2 is greater than 1.01. In one embodiment, the ratio of D1 over D2 is greater than 1.05. In another embodiment, the ratio of D1 over D2 is greater than 1.1. In another embodiment, the ratio of D1 over D2 is greater than 1.15. In another embodiment, the ratio of D1 over D2 is greater than 1.1 and less than 1.5. In another embodiment, the ratio of D1 over D2 is greater than 1.1 and less than 1.4. In another embodiment, the ratio of D1 over D2 is greater than 1.1 and less than 1.3. In another embodiment, the ratio of D1 over D2 is greater than 1.1 and less than 1.2.
In one embodiment, the ratio of D3 over D4 is greater than 1.05. In another embodiment, the ratio of D3 over D4 is greater than 1.1. In another embodiment, the ratio of D3 over D4 is greater than 1.15. In another embodiment, the ratio of D3 over D4 is greater than 1.1 and less than 1.5. In another embodiment, the ratio of D3 over D4 is greater than 1.1 and less than 1.4. In another embodiment, the ratio of D3 over D4 is greater than 1.1 and less than 1.3. In another embodiment, the ratio of D3 over D4 is greater than 1.1 and less than 1.2.
The unique crown construction and unique sole biased variable face thickness profile described herein can be used in a driver. In other embodiments, the features can be used in a fairway or a hybrid as well. In some embodiments, the unique crown construction and/or unique sole biased variable face thickness profile can be included in a golf club head having a volume greater than 250 cubic centimeters (cc). In some embodiments, the unique crown construction and/or unique sole biased variable face thickness profile can be included in a golf club head having a volume greater than or equal to 130 cc and less than 250 cc. In some embodiments, the unique crown construction and/or unique sole biased variable face thickness profile can be included in a golf club head having a volume less than 130 cc. Volumes are measured according to the Procedure for Measuring the Club Head Size of Wood Clubs, USGA-TPX3003, Revisions 1.0.0, Nov. 21, 2003, United States Golf Association.
In describing the present technology herein, certain features that are described in the context of separate implementations also can be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation also can be implemented in multiple implementations separately or in any suitable sub combination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a sub combination or variation of a sub combination.
Various modifications to the implementations described in this disclosure may be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other implementations without departing from the spirit or scope of this disclosure. Thus, the claims are not intended to be limited to the implementations shown herein, but are to be accorded the widest scope consistent with this disclosure as well as the principle and novel features disclosed herein.