US20160250530A1

US20160250530A1 - Golf club with improved weighting

Info

Publication number: US20160250530A1
Application number: US14/755,489
Authority: US
Inventors: Dustin A. Barksdale; Donald S. Bone
Original assignee: Acushnet Co
Current assignee: True Temper Sports Inc
Priority date: 2015-02-26
Filing date: 2015-06-30
Publication date: 2016-09-01

Abstract

A plurality of two or more golf clubs with improved weighting characteristics is disclosed. More specifically, the present invention discloses a specific relationship between the mass M_clubof the golf club and the length L_clubto help improve the performance of the golf club. In addition to the above, the present invention also discloses a change to the balance point of the shaft to help compensate for the change in mass M_shaftof the shaft and the length L_shaftof the shaft to maintain a desirable swing weight.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation-In-Part (CIP) of copending U.S. patent application Ser. No. 14/683,422, filed on Apr. 10, 2015, which is a Continuation-In-Part of U.S. patent application Ser. No. 14/632,933, filed on Feb. 26, 2015, the disclosure of which are all incorporated by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates generally to a set of golf clubs with improved weighting characteristics. More specifically, the present invention relates a plurality of two or more golf clubs that creates increases in mass as the clubs get shorter in length. This inverse relationship between the length of the club and the mass of the club helps improve the performance of the set of golf club heads by creating a lighter softer shaft for longer golf clubs while creating a heavier stiffer shaft for shorter irons. The present invention achieves this by focusing its attention on adjusting the mass of the shaft portion of the golf club to create the desired results. However, it should be noted that because the shaft is ultimately only a component of a golf club, the focus of the present invention is directed at a golf club with improved weighting.

BACKGROUND OF THE INVENTION

A golf club contains several key components, all of which can affect the overall performance of a golf club head. Although most golf club improvements focus on the club head portion of the golf club, significant improvements can be made to other portions of the golf club as well.
U.S. Pat. No. 7,175,538 to Miller illustrates one of these examples of improvements to other portions of the golf club head by focusing its attention on the grip of the golf club. U.S. Pat. No. 7,175,538 provides a golf club grip having the diameter of the grip progressively reduced from one the butt end to the opposing end.
U.S. Pat. No. 5,711,721 to Johnson et al. illustrates another example of an improvement to a golf club head by focusing on the ferrule of the golf club. U.S. Pat. No. 5,711,721 provides a ferrule for a golf club that has at least one raised element with a top surface and a second member molded about the first member to surround the raised element to provide logo display or indicia.
U.S. Pat. No. 5,049,422 to Honma provides an example of an improvement to the shaft portion of the golf club head. In U.S. Pat. No. 5,049,422 the inventor taught a shaft for golf club which can exhibit a vibration characteristic of a steel shaft without imparting the characteristics of a carbon shaft. The inventor does this by creating metal fibers incorporated in an outer layer portion of a carbon shaft with a specific direction of metal fiber orientation.
The present invention focuses on improving the performance of the golf club itself by adjusting, among many other factors, the shaft portion of the golf club. It utilizes a very specific relationship between the length of the golf club together with the overall mass of the golf club to create a set of golf club with improved performance throughout the entire set of golf clubs.

BRIEF SUMMARY OF THE INVENTION

In one aspect of the present invention is a golf club comprising of a club head located at a distal end of said golf club, a grip located at a proximal end of said golf club, and a shaft, juxtaposed between the club head and the grip, connecting the club head to the grip, wherein the mass M_clubof the golf club decreases with an increase in a length L_clubof said golf club in accordance with the relationship, M_club≧−20.691 L_club+1201.5.
In another aspect of the present invention is a plurality of golf clubs comprising of a first golf club having a length greater than about 38 inches having a first mass, a second golf club having a length of between about 36 to 38 inches having a second mass, and a third golf club having a length of less than about 36 inches having a third mass, wherein the first mass is less than the second mass and the second mass is less than the third mass, and wherein said first, second, and third golf club all have individual shafts that have a mass that satisfies the equation M_shaft≧−6 L_shaft+347.
In another aspect of the present invention, the golf club shaft could have a balance point that changes as a function of the length of the shaft according to the relationship Balance Point_shaft(%)≧0.1 L_shaft+26.33.
In another aspect of the present invention, the golf club shaft could have a tip frequency that changes as a function of the length of the shaft according to the relationship Tip Frequency_shaft(CPM)≦−15 L_shaft+2367.5.
In another aspect of the present invention there could be a plurality of golf clubs comprising of a first golf club shaft having a length of greater than about 37.5 inches having a first shaft mass, a second golf club shaft having a length of about 37.5 inches having a second shaft mass; and a third golf club shaft having a length of less than about 37.5 inches having a third shaft mass. The first shaft mass is less than the second shaft mass, and the second shaft mass is equal to the third shaft mass.
These and other features, aspects and advantages of the present invention will become better understood with references to the following drawings, description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features and advantages of the invention will be apparent from the following description of the invention as illustrated in the accompanying drawings. The accompanying drawings, which are incorporated herein and form a part of the specification, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention.

FIG. 1 of the accompanying drawing shows a perspective view of long-iron golf club shaft in accordance with an exemplary embodiment of the present invention;

FIG. 2 of the accompanying drawings shows a perspective view of a mid-iron golf club shaft in accordance with an exemplary embodiment of the present invention;

FIG. 3 of the accompanying drawings shows a perspective view of a short-iron golf club shaft in accordance with an exemplary embodiment of the present invention;

FIG. 4 of the accompanying drawings shows a perspective view of a long-iron, a mid-iron, and a short-iron shaft, all in accordance with an exemplary embodiment of the present invention, all next to one another; and

FIG. 5 of the accompanying drawings shows a perspective view of three golf clubs within a set of golf clubs complete with individual components such as the golf club head, the golf club shaft, and the golf club grip.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description is of the best currently contemplated modes of carrying out the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims.
Various inventive features are described below that can each be used independently of one another or in combination with other features. However, any single inventive feature may not address any or all of the problems discussed above or may only address one of the problems discussed above. Further, one or more of the problems discussed above may not be fully addressed by any of the features described below.
Due to the fact that one of the ways the present invention achieves the improvement in overall club performance improvements by adjusting the mass M_shaftof the golf club shaft as a function of the length L_shaftof the shaft, the discussion below will begin by focusing on the shaft portion of the golf club. However, because the overall performance of the golf club is what the present invention is ultimately focused on, the latter portion of this discussion will then shift to focus on the length L_clubof the golf club and the mass M_clubof the golf club.
One of the ways to achieve the desired overall club mass is by adjusting the mass M_shaftof the shaft as the length L_shaftof the shaft changes. More specifically, the present invention creates a very specific relationship between the M_shaftand the L_shaftthat creates an increase in the golf club mass M_shaftas the length L_shaftdecreases.
FIG. 1 of the accompanying drawings shows a perspective view of a golf club shaft 100 of a long-iron in accordance with an exemplary embodiment of the present invention. Here, the golf club shaft 100 has a first end, a second end, an inner diameter, and an outer diameter. The first end of the shaft may generally relate to the portion with a larger outer diameter, adapted to connected to the grip, while the second end may generally relate to the portion with a smaller outer diameter, adapted to connected to the club head. The present invention, in order to improve the performance of a golf club via the golf club shaft 100, has created a specific relationship between a length L_shaftof the golf club shaft 100 as a function to the mass M_shaftof the golf club shaft 100. More specifically, the relationship created between the length L_shaftof the golf club shaft 100 and the mass of the golf club shaft 100 is inversed, meaning a decrease in the length L_shaftof the golf club shaft 100 will equate to an increase in the mass M_shaftof the golf club shaft 100. In one exemplary embodiment of the present invention, this inverse relationship between the length L_shaftand the mass M_shaftcan be quantified by equation (1) below:
M _shaft≧−6 L _shaft+347 Eq. (1)
In one exemplary embodiment of the present invention, the long-iron golf club shaft 100 may have a length L_shaftof about 40.5 inches and mass M_shaftof greater than about 104 grams. In another exemplary embodiment of the present invention, the long-iron golf club shaft 100 may have a length L_shaftof about 40 inches and a mass M_shaftof greater than about 107 grams. In another exemplary embodiment of the present invention, the long-iron golf club shaft 100 may have a length L_shaftof about 39.5 inches and a mass M_shaftof greater than about 110 grams. In another exemplary embodiment of the present invention, the long-iron golf club shaft 100 may have a length L_shaftof about 39 inches and a mass M_shaftof greater than about 113 grams.
In order to achieve the relationship between shaft length L_shaftand mass M_shaftabove, the present invention utilizes different internal and external shaft profiles to help achieve this goal. In the current exemplary embodiment, section 101 may have an outer diameter of about 0.60 in, section 102 may have an outer diameter of about 0.59 in, section 104 may have an outer diameter of about 0.575 in, section 106 may have an outer diameter of about 0.56 in, section 108 may have an outer diameter of about 0.545 in, section 110 may have an outer diameter of about 0.530 in, section 112 may have an outer diameter of about 0.515 in, section 114 may have an outer diameter of about 0.500 in, section 116 may have an outer diameter of about 0.485 in, section 118 may have an outer diameter of about 0.470 in, section 120 may have an outer diameter of about 0.450 in, section 122 may have an outer diameter of about 0.430 in, section 124 may have an outer diameter of about 0.410 in, section 126 may have an outer diameter of about 0.395 in, and section 128 may have an outer diameter that tapers at a rate of about 0.0075 in/in until the shaft 100 reaches an outer diameter of about 0.355 inches.
Finally, it should be noted here that the outer profile of the golf club shaft 100 is stepped in its outer diameter profile, which can help provide the amount of mass adjustment needed for the current invention. However, the outer profiles of the golf club shaft 100 can be continuously tapered, parallel, or any other geometry or even alternate materials all without departing from the scope and content of the present invention.
FIG. 2 of the accompanying drawings shows a perspective view of a golf club shaft 200 of a mid-iron in accordance with an exemplary embodiment of the present invention. The mid-irons, similar to long-irons, have an inverse relationship between the length L_shaftand the mass M_shaftresulting in a similar relationship established above in Equation (1). In one exemplary embodiment of the present invention, the mid-iron golf club shaft 200 may have a length L_shaftof about 38.5 inches and mass M_shaftof greater than about 116 grams. In another exemplary embodiment of the present invention, the mid-iron golf club shaft 200 may have a length L_shaftof about 38 inches and a mass M_shaftof greater than about 119 grams. In another exemplary embodiment of the present invention, the mid-iron golf club shaft 200 may have a length L_shaftof about 37.5 inches and a mass M_shaftof greater than about 122 grams.
In order to achieve the relationship between shaft length L_shaftand mass M_shaftabove, the present invention may have a section 201 with an outer diameter of about 0.600 in, a section 202 with an outer diameter of about 0.585 in, a section 204 with an outer diameter of about 0.568 in, a section 206 with an outer diameter of about 0.553 in, a section 208 with an outer diameter of about 0.538 in, a section 210 with an outer diameter of about 0.523 in, a section 212 with an outer diameter of about 0.508, a section 214 with an outer diameter of about 0.493 in, a section 216 with an outer diameter of about 0.478 in, a section 218 with an outer diameter of about 0.463 in, a section 220 with an outer diameter of about 0.445 in, a section 222 with an outer diameter of about 0.430 in, a section 224 with an outer diameter of about 0.410 in, a section 226 with an outer diameter of about 0.395 in, and section 228 may have an outer diameter that tapers a rate of about 0.0075 in/in until the shaft 200 reaches an outer diameter of about 0.355 inches.
FIG. 3 of the accompanying drawings shows a perspective view of a golf club shaft 300 of a short-iron in accordance with an exemplary embodiment of the present invention. The short-irons, similar to long-irons and mid-irons, have an inverse relationship between the length L_shaftand the mass M_shaftresulting in a similar relationship established above in Equation (1). In one exemplary embodiment of the present invention, the short-iron golf club shaft 300 may have a length L_shaftof about 37.0 inches and mass M_shaftof greater than about 125 grams. In another exemplary embodiment of the present invention, the short-iron golf club shaft 300 may have a length L_shaftof about 36.5 inches and a mass M_shaftof greater than about 128 grams.
In order to achieve the relationship between shaft length L_shaftand mass M_shaftabove, the present invention may have a section 301 with an outer diameter of about 0.580 in, a section 302 with an outer diameter of about 0.560 in, a section 304 with an outer diameter of about 0.545 in, a section 306 with an outer diameter of about 0.530 in, a section 308 with an outer diameter of about 0.515 in, a section 310 with an outer diameter of about 0.500 in, a section 312 with an outer diameter of about 0.485, a section 314 with an outer diameter of about 0.470 in, a section 316 with an outer diameter of about 0.445 in, a section 318 with an outer diameter of about 0.440 in, a section 320 with an outer diameter of about 0.425 in, a section 322 with an outer diameter of about 0.410 in, a section 324 with an outer diameter of about 0.395 in, a section 226 with an outer diameter of about 0.395 in, and section 328 may have an outer diameter that tapers a rate of about 0.0075 in/in until the shaft 300 reaches an outer diameter of about 0.355 inches.
Although the above embodiment shows a stepped iron type golf club shaft for the long-irons, the mid-irons and the short-irons, the external profile need not be stepped. In fact, in alternative embodiments of the present invention the wall profile of the shaft may be constantly tapering, rifled, or any other profile without departing from the scope and content of the present invention so long as it achieves the relationship established in Equation (1). In fact, the material of the iron may not even need to be steel, and could be wood, carbon fiber, or any other type of material suitable for a golf club shaft also without departing from the scope and content of the present invention.
In an alternative embodiment of the present invention, the golf club shaft may have different weighting criteria depending on the desired weight, desired flex, and desired material of the shaft. In these alternative embodiments of the present invention, the relationship between the mass and the length of the golf club head may not be purely linear as shown above, but may take advantages of the needs of different golf clubs at different lengths to further alter the design.
In one alternative embodiment of the present invention, wherein the shaft could be a lightweight stiff flex steel type golf club shaft, the long irons may generally have length L_shaftof about 40.0 inches and mass M_shaftof greater than about 94.5 grams. In another exemplary embodiment of the present invention, the long-iron golf club shaft 100 may have a length L_shaftof about 39.5 inches and a mass M_shaftof greater than about 97.5 grams. In another exemplary embodiment of the present invention, the long-iron golf club shaft 100 may have a length L_shaftof about 39.0 inches and a mass M_shaftof greater than about 100.5 grams. The mid-irons according to this embodiment of the present invention may have specifications as follows with a length L_shaftof about 38.5 inches and mass M_shaftof greater than about 103.5 grams. In another exemplary embodiment of the present invention, the mid-iron golf club shaft 100 may have a length L_shaftof about 38.0 inches and a mass M_shaftof greater than about 106.5 grams. In another exemplary embodiment of the present invention, the mid-iron golf club shaft 100 may have a length L_shaftof about 37.5 inches and a mass M_shaftof greater than about 106.5 grams. The short-irons according to this embodiment of the present invention may have specifications as follows with a length L_shaftof about 37.25 inches and mass M_shaftof greater than about 106.5 grams. In another exemplary embodiment of the present invention, the short-iron golf club shaft 100 may have a length L_shaftof about 37.0 inches and a mass M_shaftof greater than about 106.5 grams.
In another alternative embodiment of the present invention, wherein the shaft could be a lightweight regular flex steel type golf club shaft, the long irons may generally have length L_shaftof about 40.0 inches and mass M_shaftof greater than about 92.5 grams. In another exemplary embodiment of the present invention, the long-iron golf club shaft 100 may have a length L_shaftof about 39.5 inches and a mass M_shaftof greater than about 95.5 grams. In another exemplary embodiment of the present invention, the long-iron golf club shaft 100 may have a length L_shaftof about 39.0 inches and a mass M_shaftof greater than about 98.5 grams. The mid-irons according to this embodiment of the present invention may have specifications as follows with a length L_shaftof about 38.5 inches and mass M_shaftof greater than about 101.5 grams. In another exemplary embodiment of the present invention, the mid-iron golf club shaft 100 may have a length L_shaftof about 38.0 inches and a mass M_shaftof greater than about 104.5 grams. In another exemplary embodiment of the present invention, the mid-iron golf club shaft 100 may have a length L_shaftof about 37.5 inches and a mass M_shaftof greater than about 104.5 grams. The short-irons according to this embodiment of the present invention may have specifications as follows with a length L_shaftof about 37.25 inches and mass M_shaftof greater than about 104.5 grams. In another exemplary embodiment of the present invention, the short-iron golf club shaft 100 may have a length L_shaftof about 37.0 inches and a mass M_shaftof greater than about 104.5 grams.
In another alternative embodiment of the present invention, wherein the shaft could be a lightweight graphite stiff flex type golf club shaft, the long irons may generally have length L_shaftof about 40.0 inches and mass M_shaftof greater than about 55.0 grams. In another exemplary embodiment of the present invention, the long-iron golf club shaft 100 may have a length L_shaftof about 39.5 inches and a mass M_shaftof greater than about 58.0 grams. In another exemplary embodiment of the present invention, the long-iron golf club shaft 100 may have a length L_shaftof about 39.0 inches and a mass M_shaftof greater than about 61.0 grams. The mid-irons according to this embodiment of the present invention may have specifications as follows with a length L_shaftof about 38.5 inches and mass M_shaftof greater than about 64.0 grams. In another exemplary embodiment of the present invention, the mid-iron golf club shaft 100 may have a length L_shaftof about 38.0 inches and a mass M_shaftof greater than about 67.0 grams. In another exemplary embodiment of the present invention, the mid-iron golf club shaft 100 may have a length L_shaftof about 37.5 inches and a mass M_shaftof greater than about 70.0 grams. The short-irons according to this embodiment of the present invention may have specifications as follows with a length L_shaftof about 37.0 inches and mass M_shaftof greater than about 70.0 grams. In another exemplary embodiment of the present invention, the short-iron golf club shaft 100 may have a length L_shaftof about 36.75 inches and a mass M_shaftof greater than about 70.0 grams. In another exemplary embodiment of the present invention, the short-iron golf club shaft 100 may have a length L_shaftof about 36.50 inches and a mass M_shaftof greater than about 70.0 grams.
In another alternative embodiment of the present invention, wherein the shaft could be a lightweight graphite regular flex type golf club shaft, the long irons may generally have length L_shaftof about 40.0 inches and mass M_shaftof greater than about 52.0 grams. In another exemplary embodiment of the present invention, the long-iron golf club shaft 100 may have a length L_shaftof about 39.5 inches and a mass M_shaftof greater than about 55.0 grams. In another exemplary embodiment of the present invention, the long-iron golf club shaft 100 may have a length L_shaftof about 39.0 inches and a mass M_shaftof greater than about 58.0 grams. The mid-irons according to this embodiment of the present invention may have specifications as follows with a length L_shaftof about 38.5 inches and mass M_shaftof greater than about 61.0 grams. In another exemplary embodiment of the present invention, the mid-iron golf club shaft 100 may have a length L_shaftof about 38.0 inches and a mass M_shaftof greater than about 64.0 grams. In another exemplary embodiment of the present invention, the mid-iron golf club shaft 100 may have a length L_shaftof about 37.5 inches and a mass M_shaftof greater than about 67.0 grams. The short-irons according to this embodiment of the present invention may have specifications as follows with a length L_shaftof about 37.0 inches and mass M_shaftof greater than about 67.0 grams. In another exemplary embodiment of the present invention, the short-iron golf club shaft 100 may have a length L_shaftof about 36.75 inches and a mass M_shaftof greater than about 67.0 grams. In another exemplary embodiment of the present invention, the short-iron golf club shaft 100 may have a length L_shaftof about 36.50 inches and a mass M_shaftof greater than about 67.0 grams.
It can be seen from above that in these lightweight embodiments of the present invention, the shaft may generally have a mass M_shaftthat increases in 3 gram increments as the irons decreases in length L_shaftin half inch increments. It should be noted though that this increase in mass M_shaftas a function of the decreases in length L_shaftceases to occur when the golf club shaft length decreases to about 37.5 inches in these lightweight embodiments. In fact, once the golf club shaft's length L_shaftreaches about 37.5 inches, the M_shaftstays fairly constant for any length that is shorter than about 37.5 inches. This specific mass progression is beneficial to these lightweight golf club shafts in steel or graphite because it will prevent the mass M_shaftof the shaft to get excessively heavy, thus negating the purpose of creating a lightweight shaft.
I should be noted above that the point where the golf club shaft ceases to increase in length being at about 37.5 is not an absolute number. In fact, a closer look at the data above shows that in the weight increases for graphite golf club shafts stop at about 37.5 inches while the weight increase for steel golf club shafts actually stop at 38 inches. Alternatively, in order to provide more consistency to the paragraph above, it can be said that the golf club shaft ceases to increase in mass M_shaftwhen the shaft within the set increases by about 10 grams to about 20 grams from the lightest shaft within the plurality of golf club shafts. To put it in another way, it can be said that the golf club shaft ceases to increase in mass M_shaftwhen the shaft within the set increases by about 10 to 30 percent in mass from the lightest shaft within the plurality of golf club shafts.
Before the discussion here moves onto the actual golf club assembly itself, it is worth noting additional key features of the present golf club shaft that makes the present invention unique. First off, in addition to the weighting and diameter above, the inventive golf club shaft in accordance with the present invention will have a balance point that deceases as the length of the shaft gets shorter. Balance point, as commonly known in the industry, relates to the point where the center of gravity of the golf club shaft is concentrated, thus allowing the golf club to be balanced at that point. Balance point, in most common scenarios is defined as a percentage of the total club distance, measured from the butt end of the shaft. Thus, for example, a golf club shaft with a balance point of 50% and a length of 40 inches, will balance itself at a distance of 20 inches from the butt end. In another example, a golf club shaft with a balance point of 40% and a length of 40 inches, will balance itself at a distance of 16 inches from the butt end. Ultimately, it can be said that the slope of the trend line created by the relationship between the balance point and the length of the shaft may generally be governed by Equation (2) below,
Balance Point_shaft(%)≧0.1 L _shaft+26.33 Eq. (2)
more preferably governed by Equation (3) below,
Balance Point_shaft(%)≧0.3 L _shaft+26.33 Eq. (3)
and most preferably governed by Equation (4) below,
Balance Point_shaft(%)≧0.5 L _shaft+26.33 Eq. (4)
Having a balance point location that changes with respect to a change in shaft length is important to the present invention because as the mass of the shafts go up, the swing weight of the golf club could be adversely affected if the balance point is not adjusted. Although changes in swing weight of a golf club could be subtle side effects of can often go ignored, recognizing this important side effect and addressing it by adjusting the balance point is critical to the proper functionality of the present invention.
In one exemplary embodiment of the present invention, the golf club shaft may have a length of 40.5 inches with a balance point of 51.46%, a length of 40 inches with a balance point of 51.25%, a length of 39.5 inches with a balance point of 50.76%, a length of 39 inches with a balance point of 50.33%, a length of 38.5 inches with a balance point of 50.03%, a length of 38 inches with a balance point of 50.03%, a length of 37.5 inches with a balance point of 49.2%, a length of 37 inches with a balance point of 49.24%, and finally a length of 36.5 inches with a balance point of 49.18%.
In addition to the balance point identified above, the present invention incorporates another important feature that works in conjunction with the mass of the golf club head changing throughout a set of golf clubs to further improve the performance of the golf club head. In the current exemplary embodiment, as shown above, the mass of the golf club head increases as the length of the golf club shaft gets shorter. However, in order to help preserve the performance of these irons in certain situations where the walls need to be thinned, the present invention increases the overall tip frequency of these golf club heads to improve performance. In one exemplary embodiment a golf club having a length of 40.5 inches will have a tip frequency of 808 CPM (Cycles Per Minutes), a golf club shaft having a length of 40 inches will have a tip frequency of 867 CPM, a golf club shaft having a length of 39.5 inches will have a tip frequency of 860 CPM, a golf club shaft having a length of 39 inches will have a tip frequency of 878 CPM, a golf club shaft having a length of 38.5 inches will have a tip frequency of 879 CPM, a golf club shaft having a length of 38 inches will have a tip frequency of 952 CPM, a golf club shaft having a length of 37.5 inches will have a tip frequency of 945 CPM, a golf club shaft having a length of 37 inches will have a tip frequency of 936 CPM, and a golf club shaft having a length of 36.5 inches will have a tip frequency of 981 CPM.
Based on the information above, it can be said that a shaft in accordance with an exemplary embodiment of the present invention may generally have a higher tip frequency than a traditional shaft that has similar weighting characteristics. In addition to having a higher tip frequency, it can be said that the relationship between the tip frequency and the length of the shaft may generally be governed by Equation (5) below,
Tip Frequency_shaft(CPM)≦−15 L _shaft+2367.5 Eq. (5)
more preferably governed by Equation (6) below,
Tip Frequency_shaft(CPM)≦−20 L _shaft+2367.5 Eq. (6)
and most preferably governed by Equation (7) below,
Tip Frequency_shaft(CPM)≦−30 L _shaft+2367.5 Eq. (7)
FIG. 4 of the accompanying drawings shows a perspective view of all three of the shafts discussed earlier, the long-iron shaft 100, the mid-iron shaft 200, and the short-iron shaft 300 next to one another for an illustration of the relative length of one another.
Finally, returning to the discussion regarding the golf club itself, FIG. 5 of the accompanying drawings shows a perspective view of all three golf club shafts 100, 200, and 300 being connected to their respective components. This illustration will bring the entire invention together in establishing a relationship between the overall club length L_clubof the golf clubs 107, 207, and 307 and the overall club mass M_clubcan be established. It is important to establish the criticality of the discussion focusing on the overall club mass M_clubas well as the overall club length L_clubbecause that specific relationship is the one that controls performance. Returning to FIG. 5 we can see that the overall club mass M_clubas well as the overall club length L_clubare all functions of three main components, the club head 103, 203 and 303, the shaft 100, 200, and 300, as well as the grip 105, 205, and 305. Taking into consideration of these components, the following relationship can be established as shown by Equation (8) below:
M _club≧−20.691 L _club+1201.5 Eq. (8)
In one exemplary embodiment of the present invention the golf clubs 107, 207, and 307 may have a length L_clubof about 39 inches and mass M_clubof greater than about 396 grams. In another exemplary embodiment of the present invention, invention the golf clubs 107, 207, and 307 may have a length L_clubof about 38.5 inches and mass M_clubof greater than about 405 grams. In another exemplary embodiment of the present invention, invention the golf clubs 107, 207, and 307 may have a length L_clubof about 38 inches and mass M_clubof greater than about 415 grams. In another exemplary embodiment of the present invention, invention the golf clubs 107, 207, and 307 may have a length L_clubof about 37.5 inches and mass M_clubof greater than about 424 grams. In another exemplary embodiment of the present invention, invention the golf clubs 107, 207, and 307 may have a length L_clubof about 37 inches and mass M_clubof greater than about 435 grams. In another exemplary embodiment of the present invention, invention the golf clubs 107, 207, and 307 may have a length L_clubof about 36.5 inches and mass M_clubof greater than about 446 grams. In another exemplary embodiment of the present invention, invention the golf clubs 107, 207, and 307 may have a length L_clubof about 36 inches and mass M_clubof greater than about 456 grams. In another exemplary embodiment of the present invention, invention the golf clubs 107, 207, and 307 may have a length L_clubof about 35.75 inches and mass M_clubof greater than about 464 grams.
Based on the above, it can be seen that if you have a plurality of two or more of golf clubs in a set of golf clubs, there will be a relationship established between the mass M_cluband the overall club length L_clubsuch that the longer clubs will be lighter while the shorter clubs will be heavier. In addition to the above, although the above discussion is directed at a set of iron type golf clubs, this progressive relationship could be applied across an entire set of golf clubs from a driver of up to 48 inches down to a putter down to 32 inches, all without departing from the scope and content of the present invention.
It should be noted that although the dominant contributor to the adjustment in overall club mass M_cluband the overall club length L_clubmay be the shaft mass M_shaftand the shaft length L_shaft, the other components are just as important in contributing in creating the relationship articulated above in Equation (2). In fact, adjustments could be made to the club head 103, 203 and 303 as well as the grip 105, 205, and 305 to achieve the relationship articulated above in Equation (2) without departing from the scope and content of the present invention.
Alternatively, it can be said that the present invention relates to a plurality of golf clubs having a first golf club having a length greater than 38 inches, a second golf club having a length of between about 36 to 38 inches, and a third golf club having a length less than about 36 inches. The first golf club will generally have the lightest mass with a first mass, while the second golf club will generally have a mass that is heavier than the first mass, with the third golf club having a third mass, which is greater than the first mass and the second mass. Ultimately, the specific relationship created between the mass and the length of the golf club is beneficial in helping improve the performance of the golf club, despite its counter-intuitive nature. Generally speaking, when a golf club is shorter, the mass of the golf club shaft decreases when a uniform material shaft is trimmed. This antiquated wisdom leaves the golf club shaft to be heaviest at higher lofts and lighter at lower lofts. The present invention improves upon this methodology by reversing the conventional thinking with a more performance based design approach. In order to help golfers swing the longest golf club in their bag the best, it is beneficial to help reduce the mass of the golf club in those longer clubs, which ultimately results in an increase in the mass of the shorter irons. The present invention takes advantage of that unconventional methodology and has created a very specific relationship for those variable.
Other than in the operating example, or unless otherwise expressly specified, all of the numerical ranges, amounts, values and percentages such as those for amounts of materials, moment of inertias, center of gravity locations, loft, draft angles, various performance ratios, and others in the aforementioned portions of the specification may be read as if prefaced by the word “about” even though the term “about” may not expressly appear in the value, amount, or range. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the preceding 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.
It should be understood, of course, that the foregoing relates to exemplary embodiments of the present invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims.

Claims

What is claimed is:

1. A plurality golf club shafts comprising;

a first golf club shaft having a length of greater than about 37.5 inches having a first shaft mass;

a second golf club shaft having a length of about 37.5 inches having a second shaft mass;

a third golf club shaft having a length of less than about 37.5 inches having a third shaft mass;

where said first shaft mass is less than said second shaft mass, and

wherein said second shaft mass is equal to said third shaft mass.

2. The plurality of golf club shafts of claim 1, wherein said first shaft mass is greater than about 94.5 grams.

3. The plurality of golf club shafts of claim 2, wherein said second shaft mass and said third shaft mass are both about 106.5 grams.

4. The plurality of golf club shafts of claim 1, wherein said first shaft mass is greater than about 92.5 grams.

5. The plurality of golf club shafts of claim 4, wherein said second shaft mass and said third shaft mass are both about 104.5 grams.

6. The plurality of golf club shafts of claim 1, wherein said first shaft mass is greater than about 55 grams.

7. The plurality of golf club shafts of claim 6, wherein said second shaft mass and said third shaft mass are both about 70 grams.

8. The plurality of golf club shafts of claim 1, wherein said first shaft mass is greater than about 52 grams.

9. The plurality of golf club shafts of claim 8, wherein said second shaft mass and said third shaft mass are both about 67 grams.

10. The plurality of golf club shafts of claim 1, wherein said first golf club shaft, said second golf club shaft, and said third golf club shaft, all have a Balance Point_shaftthat increases as said length L_shaftincreases according to the relationship,

Balance Point_shaft(%)≧0.1 L _shaft+26.33.

11. The plurality of golf club shafts of claim 10, wherein said relationship between said Balance Point_shaftand said length L_shaftis,

Balance Point_shaft(%)≧0.3 L _shaft+26.33.

12. The plurality of golf club shafts of claim 10, wherein said relationship between said Balance Point_shaftand said length L_shaftis,

Balance Point_shaft(%)≧0.5 L _shaft+26.33.

13. A golf club shaft comprising:

a first end, a second end, an inner diameter, and an outer diameter;

wherein a mass M_shaftof said shaft is determined as a function of a length L_shaft;

wherein if said length L_shaftis greater than about 37.5 inches, said mass M_shaftincreases inversely with the decrease in length L_shaft;

wherein if said length L_shaftis less than or equal to about 37.5 inches, said mass M_shaftstays constant irrespective of any change in length L_shaft.

14. The golf club shaft of claim 13, wherein said shaft has a Balance Point_shaftthat increases as said length L_shaftincreases according to the relationship,

Balance Point_shaft(%)≧0.1 L _shaft+26.33.

15. The golf club shaft of claim 14, wherein said shaft has a Balance Point_shaftthat increases as said length L_shaftincreases according to the relationship,

Balance Point_shaft(%)≧0.3 L _shaft+26.33.

16. The golf club shaft of claim 13, wherein said shaft has a Balance Point_shaftthat increases as said length L_shaftincreases according to the relationship,

Balance Point_shaft(%)≧0.5 L _shaft+26.33.

17. A plurality of golf club shafts comprising:

a first golf club shaft having a first length and a first shaft mass;

a second golf club shaft having a second length and a second shaft mass; and

a third golf club shaft having a third length and a third shaft mass,

wherein said first length is greater than said second length, and said second length is greater than said third length,

wherein said first shaft mass is less than said second shaft mass, and said second shaft mass is equal to said third shaft mass, and

wherein said second and third shaft mass is about 15 grams to about 20 grams higher than said first shaft mass.

18. The plurality of golf club shafts of claim 17, wherein said first shaft mass is greater than about 92.5 grams.

19. The plurality of golf club shafts of claim 17, wherein said first shaft mass is greater than about 52 grams.