SYSTEMS AND METHODS FOR FITTING GOLF CLUBS TO GOLFERS

Abstract

A system for fitting golf clubs to golfers that enables an overall club length to be varied without varying the length of the golf club shaft. The system enables a greater number of combinations of club characteristics, such as shaft flex, brand, and length, to be contained within a club fitting cart and/or for a same number of combinations of club characteristics to be contained within a smaller cart.

Description

BACKGROUND

Generally, the concepts described herein relate to golf clubs (e.g., drivers, fairway woods, irons, wedges, putters, etc.). More particularly, in some embodiments the concepts described herein relate to custom golf club fittings. For the sake of clarity and brevity, the concepts will be described in detail below with respect to wedge-type golf clubs, but could be applied to any type of golf clubs.

Each golfer has a different swing type and physical characteristics (e.g., golfer's height, weight, arm-length, etc.). In order to properly fit a set of golf clubs (e.g., a set of irons, a set of wedges, or an entire set of golf clubs including irons, wedges, etc.) for any particular golfer, a fitting process is generally employed to determine the proper specifications for each golf club in the golfer's bag.

The golf club fitting process generally requires a golfer to swing a golf club under the supervision of a golf club fitting specialist. Based on the results, the golf club fitting specialist may suggest adjustments to various golf clubs (e.g., switching to a different shaft length, a different shaft stiffness or “flex,” etc.), or ask the golfer to try a different golf club altogether. The golfer may continue to swing the adjusted golf club, and further adjustments may be made if necessary. Through this process, the golfer may arrive at a set of custom-fit golf clubs that is adapted for that individual.

However, such a process requires the golf club fitting specialist to carry a large number of golf club components, particularly club heads and shafts. For example, for each club head, there may be tens to hundreds of shafts needed to ensure a best fit for a golfer, since shafts come in different lengths, flexes, brands, etc. Typically, to assure that the golfer is provided the opportunity to find the best-fit club, the golfer must be provided with a large number of club heads and club shafts to be combined in various combinations during the fitting process.

With respect to wedges, assuming that the variables for golf club shafts are limited to brand, shaft length, and shaft flex or stiffness, the maximum number of shafts needed to be carried by a golf club fitting specialist to ensure a full library of customization options can generally be calculated with the following expression:

S=Σ _i=1 ⁿ B·CL·SL,   (1)

where S is the total number of shafts needed, n represents the number of club heads with different wedge lofts offered, B represents the number of brands offered, CL represents the number of club lengths offered, and SL represents the number of stiffness levels offered. One skilled in the art will understand that this expression may be easily reconfigured to account for additional variables, and is a mere generalization, since not every brand of shaft necessarily offers each length and stiffness.

Assuming that a manufacturer provides club heads with eight different wedge lofts (e.g., 46°, 48°, 50°, 52°, 54°, 56°, 58°, and 60°), and for each wedge loft, two different brands of shafts, with each brand providing five different club lengths at four different stiffness levels (e.g., A-flex, R-flex, S-flex, and X-flex), the manufacturer may have to provide a fitting specialist with eight wedge heads (one for each of the eight loft angles LA) and approximately 320 different shafts.

One reason why such a large number of shafts is required is that each different club head may require its own set of customizable shafts. For instance, the recommended shafts for a 46° pitching wedge range from 32.775 inches to 33.775 inches (in 0.5 inch increments), while the recommended shafts for a 58° lob wedge range from 32.405 inches to 33.405 inches (in 0.5 inch increments). Therefore, otherwise similar shafts (e.g. same brand and same flex), cannot necessarily be mixed and matched between wedges of different lofts.

Further, a typical golf club fitting specialist works at multiple retail fitting sites, and must transport his or her fitting equipment between each fitting site using a “fitting cart.” FIG. 1 illustrates an example of a typical “fitting cart” 100. The fitting cart 100 includes storage space for multiple shafts 102, multiple club heads 104, and associated tools (not shown) for securing each head 102 to each shaft 104. The cart 100 further typically includes wheels 106 to enhance its portability. Since storage space within the cart 100 is limited, and since the size of the cart 100 is limited by considerations of weight and portability, it is not practical for the fitting specialist to carry several hundred different shafts.

Thus, one alternative is to limit the golfer to a subset of golf shafts and club heads that can be practically carried by the golf club fitting specialist. The drawback of this option is that the fitting specialist has a smaller pool of customizations to offer the golfer, which inevitably requires compromises to be made during the fitting process. Therefore, there is a need for a system that allows thorough fitting of golf clubs for golfers, while reducing the number of shafts needed to be carried by the fitting specialist.

SUMMARY

The present embodiments have several features, no single one of which is solely responsible for their desirable attributes. Without limiting the scope of the present embodiments as expressed by the claims that follow, their more prominent features now will be discussed briefly. After considering this discussion, and particularly after reading the section entitled “Detailed Description,” one will understand how the features of the present embodiments provide the advantages described herein.

One embodiment of this disclosure is a golf club fitting system, comprising a first club head having a first striking face, a first main body, a first hosel extending from the first main body, a first loft angle LA₁, and a first hosel length HL₁. The system further comprises a second club head having a second striking face, a second main body, a second hosel extending from the second main body, a second loft angle LA₂ greater than the first loft angle LA₁ by no more than 15°, and a second hosel length HL₂ less than the first hosel length HL₁ by at least 0.340 inches.

Another embodiment is a golf club fitting system, comprising a first club head having a first striking face, a first main body, a first hosel extending from the first main body, a first loft angle LA₁, and a first hosel length HL₁. The system further comprises a second club head having a second striking face, a second main body, a second hosel extending from the second main body, a second loft angle LA₂ greater than the first loft angle LA₁ by no more than 5°, and a second hosel length HL₂ less than the first hosel length HL₁ by at least 0.120 inches.

Still another embodiment is a golf club fitting system, comprising a first club head having a first striking face, a first main body, a first hosel extending from the first main body, a first loft angle LA₁, and a first hosel length HL₁. The system further comprises a second club head having a second striking face, a second main body, a second hosel extending from the second main body, a second loft angle LA₂ greater than the first loft angle LA₁ by at least 4°, and a second hosel length HL₂. The first and second golf club heads satisfy the following condition: (HL₁−HL₂)=R*(LA₂−LA₁), where R is a constant within the range of 0.025 inches/degree to 0.035 inches/degree.

A still further embodiment is a golf club fitting system, comprising a first club head having a first striking face, a first main body, a first hosel extending from the first main body, a first loft angle LA₁, and a first hosel length HL₁. The system further comprises a second club head having a second striking face, a second main body, a second hosel extending from the second main body, a second loft angle LA₂ greater than LA₁ angle by at least 4°, and a second hosel length HL₂. The system further comprises a third club head having a third striking face, a third main body, a third hosel extending from the third main body, a third loft angle LA₃ greater than LA₂ by at least 4°, and a third hosel length HL₃. The first, second and third golf club heads are configured to satisfy the following condition: 3.66 in. —(0.03125 in/degree*LA_n)≦HL_n≦3.78 in −(0.03125 in/degree*LA_n) where n is 1, 2, or 3, corresponding to the first, second, and third club heads, respectively.

Still another embodiment is a golf club fitting system, comprising a first club head having a first loft greater than 45° and a first hosel length, HL₁, a second club head having a second loft greater than the first loft and a second hosel length, HL₂, less than the first hosel length and a third club head having a third loft greater than the second loft and a third hosel length, HL₃, less than the second hosel length, wherein HL₁=(HL₂−l)=(HL₃−2l). In other words, HL₁ is shorter than HL₂ by the quantity l and shorter than HL₃ by the quantity 2l, where l could be any increment of length.

Still another embodiment is a golf club fitting system, comprising a golf club head including a body portion having a first tubular passage and a plurality of first castellations arranged about an upper end of the first tubular passage. The first castellations extend upward. The system further comprises a sleeve portion including a second tubular passage configured to receive a golf club shaft, and further including a shaft portion having a plurality of second castellations arranged about an upper end thereof The second castellations extend downward. The first tubular passage receives the shaft portion, and the first and second castellations seat with one another in a first configuration to define a first overall golf club length.

Still another embodiment is a golf club fitting system, comprising a golf club head including a hosel having a first tubular passage. The hosel has a slot in a sidewall thereof defining a plurality of detents. The system further comprises a tubular adapter having a radial protrusion. The adapter includes a second tubular passage configured to receive a golf club shaft. The radial protrusion may be seated in any of the detents in the slot to vary the extent to which the adapter and the golf club shaft extend into the first tubular passage to thereby vary an overall golf club length.

Still another embodiment is a method for fitting a set of golf clubs to a golfer. The method comprises securing a first golf club head to a golf club shaft such that the golf club shaft extends a first distance into the first golf club head. The method further comprises removing the first golf club head from the golf club shaft, and then securing a second golf club head to the golf club shaft such that the golf club shaft extends a second distance into the second golf club head. The first and second distances are different.

Still another embodiment is a golf club fitting system, comprising at least two golf club heads, and a golf club shaft. The system is configurable to provide a plurality of golf club lengths using only the at least two golf club heads and the golf club shaft.

Still another embodiment is a golf club fitting system, comprising a plurality of golf club heads having different loft angles, and at least one golf club shaft. The number of the golf club shafts needed to fit a given number of the golf club head loft angles is not dependent upon the given number of loft angles.

Still another embodiment is a golf club fitting system, comprising a golf club head including a body portion having a first tubular passage and a plurality of first castellations arranged about an upper end of the first tubular passage. The first castellations extend upward. The golf club fitting system further comprises a collar portion including a second tubular passage configured to receive a golf club shaft having a shaft length, and further including a plurality of second castellations arranged about a lower end thereof The second castellations extend downward. The first and second castellations seat with one another in a first configuration to define, in combination with the golf club shaft having the shaft length, a first overall golf club length. The first and second castellations seat with one another in a second configuration to define, in combination with the golf club shaft having the shaft length, a second overall golf club length, wherein the first and second overall golf club lengths are different. When the first and second castellations seat with one another in the first configuration, the collar portion may define a first rotational orientation with respect to the body portion, and when the first and second castellations seat with one another in the second configuration, the collar portion may define a second rotational orientation with respect to the body portion. The first castellations may comprise a pair of first upwardly-extending diametrically-opposed tabs, and a pair of second upwardly-extending diametrically-opposed tabs. The first tabs may be measurably longer axially than the second tabs. The first tabs may be offset from the second tabs by about 90° around the perimeter of the first tubular passage. The second castellations may comprise a pair of first diametrically-opposed slots configured to receive the first tabs and a pair of second diametrically-opposed slots configured to receive the second tabs. The golf club fitting system may further comprise a plug portion extending from the collar portion, wherein the first tubular passage of the body portion receives the plug portion.

Still another embodiment is a golf club fitting system, comprising a golf club head including a hosel having a first tubular passage, the hosel having a slot in a sidewall thereof defining a plurality of detents. The golf club fitting system further comprises a tubular adapter having a radial protrusion. The adapter includes a second tubular passage configured to receive a golf club shaft having a shaft length. The radial protrusion is configured to be seated in any of the detents in the slot to vary an extent to which the adapter and the golf club shaft having the shaft length extend into the first tubular passage to thereby vary an overall golf club length using the golf club shaft having the shaft length. The slot defines two detents. The golf club fitting system may further comprise a securement mechanism configured to removably secure the adapter to the golf club shaft and to the golf club head. The securement mechanism may comprise one or more set screws.

Still another embodiment is a method for fitting a set of golf clubs to a golfer, the method comprising securing a first golf club head to a golf club shaft such that the golf club shaft extends a first distance into the first golf club head. The method for fitting a set of golf clubs to a golfer further comprises removing the first golf club head from the golf club shaft. The method for fitting a set of golf clubs to a golfer further comprises securing a second golf club head to the golf club shaft such that the golf club shaft extends a second distance into the second golf club head. The first and second distances are different. The first and second distances respectively correspond to first and second rotational orientations of the golf club heads to the golf club shaft. The first rotational orientation of the golf club heads to the golf club shaft may be offset by about 90° from the second rotational orientation of the golf club heads to the golf club shaft.

Still another embodiment is a golf club fitting system, comprising at least two golf club heads, and a golf club shaft. The system may be configurable to provide a plurality of golf club lengths using only the golf club heads and the golf club shaft. Providing the plurality of golf club lengths may comprise varying an extent to which the golf club shaft extends into the golf club heads. Providing the plurality of golf club lengths may comprise varying a hosel length of a golf club formed from the golf club heads and the golf club shaft. The golf club fitting system may further comprise a plurality of hosel-like sleeves having variable bore lengths, wherein the sleeves are alternately receivable within a bore in each of the golf club heads. The golf club fitting system may further comprise a plurality of adapters, wherein the adapters are receivable within a bore in each of the golf club heads to selectively limit an extent to which the golf club shaft may extend into each of the golf club heads.

BRIEF DESCRIPTION OF THE DRAWINGS

The present embodiments now will be discussed in detail with an emphasis on highlighting the advantageous features. These embodiments depict the novel and non-obvious golf club fitting systems and methods as shown in the accompanying drawings, which are for illustrative purposes only. These drawings include the following figures, in which like numerals indicate like parts:

FIG. 1 is a front perspective view of a typical fitting cart for containing and transporting a golf club fitting system;

FIG. 2 is a front elevation view of a golf club fitting apparatus, in accordance with embodiments of this disclosure;

FIG. 3 is a graph of hosel length HL versus loft angle LA for use in accordance with an embodiment of this disclosure;

FIG. 4 is a graph of hosel length HL versus loft angle LA for use in accordance with another embodiment of this disclosure;

FIG. 5 is a front perspective view of a body element of an adapter system for varying an overall length of a golf club, in accordance with a first embodiment of the disclosure;

FIG. 6 is a front perspective view of a sleeve element of the adapter system for varying an overall length of a golf club in accordance with the first embodiment;

FIGS. 7 and 8 are front perspective views of the body element and sleeve element of FIGS. 5 and 6 engaged in a first orientation and a second orientation, respectively;

FIGS. 9 and 10 are front elevation views of a golf club head and an adapter system for varying the length of a golf club in accordance with a second embodiment of the disclosure, with the adapter system engaged in a first a configuration and a second configuration, respectively;

FIG. 11 is a cross-sectional view of the golf club head and the adapter system of FIGS. 9 and 10 taken through the line 11-11 of FIG. 10;

FIG. 12 is a cross-sectional view of another embodiment of a system for varying an overall length of a golf club;

FIG. 13A is a side elevation view of a set of inserts for varying an overall length of a golf club in accordance with a third embodiment of the disclosure;

FIGS. 13B-13C are cross-sectional views of the inserts of FIG. 13A in combination with a golf club head and golf club shaft;

FIGS. 14A-14B are cross-sectional views of a fourth embodiment of a system for varying an overall length of a golf club;

FIGS. 15A-15B are side elevation views of a fifth embodiment of a system for varying an overall length of a golf club;

FIG. 16 is a flowchart illustrating one embodiment of a method of fitting a set of golf clubs to a golfer;

FIG. 17 is a side elevation view of a sixth embodiment of a system for varying an effective length of a golf club; and

FIGS. 18A-18B are side elevation views of a seventh embodiment of a system for varying an overall length of a golf club.

DETAILED DESCRIPTION

Terminology

The following terms may be used herein with respect to golf club loft angles LA, or the angle that the club face makes with the ground when the sole of the club head lies flat on the ground (higher loft angles LA generally produce higher ball trajectories and shorter ball carries):

Pitching Wedge (abbreviated PW)—A golf club typically having a loft angle LA between 40° and 50°;

Gap Wedge/Approach Wedge (abbreviated GW/AW)—A golf club typically having a loft angle LA between 45° and 55°;

Sand Wedge (abbreviated SW)—A golf club typically having a loft angle LA between 50° and 60°; and

Lob Wedge (abbreviated LW)—A golf club typically having a loft angle LA between 55° and 65°.

The following terms may be used herein with respect to the stiffness or “flex” of golf club shafts (stiffer shafts are generally intended for skilled players who can produce greater club head speeds):

L-Flex—Ladies Flex (the most flexible shaft);

A-Flex—Senior Flex;

R-Flex—Regular Flex;

S-Flex—Stiff Flex; and

X-Flex—Extra Stiff Flex (the stiffest shaft).

In some embodiments, the proposed solution offered herein to the problem discussed above involves varying the hosel length of different clubs to enable a golf club fitting specialist to use a shaft of a particular length across different clubs, thereby reducing the total number of shafts that the fitting specialist needs to carry between retail fitting sites. And, because a golfer typically only carries a few wedges (e.g., 2 or 3 wedges) as opposed to a more substantial number (e.g., 6 or more) of longer irons in his or her golf bag, the below description works particularly well for wedge fitting, but is not limited to wedges. It could be adapted for any other type of golf club.

In other embodiments, the proposed solution offered herein to the problem discussed above involves varying an extent to which the golf club shaft extends into the hosel of the golf club head. Such embodiments may comprise varying the bore length BL across different club heads, or providing an interface that enables the club shaft to extend into the bore of the club head at more than one length. Thus, while the hosel lengths of the club heads in a set may remain constant, the overall club length varies according to how far the shaft extends into the hosel.

FIG. 2 illustrates a golf club fitting apparatus that includes a reference club 10 comprising the components of a conventional golf club, which in this specific example is a wedge. The reference club 10 has a club head 12 having a heel 14 merging into a hosel 16 having a bore 18, into which the bottom end 19 of a shaft 20 is removably inserted. The club head 12 has a striking face 22 and a bottom or sole 24. A resilient grip 26 is fitted onto the upper portion of the shaft 20. A grip cap 28 typically terminates the grip 26 and covers the top end of the shaft 20 (i.e., the end of the shaft 20 opposite the hosel 16).

The reference club 10 is used in conjunction with a measurement device to measure golf club dimensions for fitting one or more golf clubs to a particular golfer in accordance with this disclosure. The measurement device includes a linear measurement element 32 with a stop member 34 at one end. The linear measurement element 32 is marked in the desired measurement units (typically inches and fractions thereof in countries that use the English system of measurement, but could be cm and mm in those countries that use the metric system). In use, the reference club 10 is oriented relative to the measurement device so that, when the linear measurement element 32 is horizontal, with the stop member 34 projecting vertically upward, the heel 14 of the club head 12 and the grip 26 of the reference club 10 are resting on the linear measurement element 32, the striking face 20 of the club head 12 is generally vertically oriented, the sole 22 of the club head 12 rests against the stop member 34, and the longitudinal axis A of the club shaft 14 is substantially parallel to the linear measurement element 32. Once the reference club 10 is properly oriented relative to the measurement device, the club length CL is read from the linear measurement element 32 at a juncture 36 between the grip 24 and the grip cap 26. Those skilled in the art will appreciate that the grip cap 26 is not included in the club length measurement CL.

The shaft length SL is a measurement of the shaft 20 from the grip/grip cap juncture 36 to the lower end of the shaft 20 (shown housed in and contacting a shaft seating surface 38 in the hosel 16 and indicated by the phantom vertical line C). The bore length BL is a length of the bore 18 between the top of the hosel 16 (where the shaft 14 enters the hosel, as indicated by the phantom vertical line B) and the shaft seating surface 38 in the hosel 16 (as indicated by the phantom vertical line C).

The hosel length HL is a measurement of the distance between the stop element 34 and the shaft seating surface 38 in the hosel 16. This measurement may be read from the linear measurement element 32 at the position of the shaft seating surface 38 in the hosel 16 (i.e., at a position coincident with the phantom vertical line C).

The fitting apparatus, including the reference club 10 and the measurement device of FIG. 2, having been described, several example embodiments are described below.

One embodiment comprises a set of club heads having typical wedge-type loft angles LA, such as a 46° PW, a 48° PW, a 50° GW, a 52° AW, a 54° SW, a 56° SW, a 58° LW and a 60° LW. As described in detail below, by configuring the hosel length HL of each club head, a single shaft can be used interchangeably with all club heads of the set in order to achieve the desired club length CL. In the foregoing embodiment, eight club heads are provided, but in alternative embodiments any number of club heads could be provided. Further, the listed loft angles LA are merely examples, and should not be construed as limiting.

With respect to a standard length, Table 1 illustrates data (in inches) for each of the eight wedge club heads in the present embodiment, including 1) hosel length HL, 2) bore length BL, 3) shaft length SL, and 4) club length CL.

TABLE 1
SET OF WEDGES
	HL	BL	SL	CL
46° PW	2.22″	0.354″	33.28″	35.5″
48° PW	2.22″	0.354″	33.28″	35.5″
50° GW	2.095″	0.354″	33.28″	35.375″
52° AW	2.095″	0.354″	33.28″	35.375″
54° SW	1.97″	0.354″	33.28″	35.25″
56° SW	1.97″	0.354″	33.28″	35.25″
58° LW	1.845″	0.354″	33.28″	35.125″
60° LW	1.845″	0.354″	33.28″	35.125″

The club lengths shown in Table 1 are considered in the industry to be “standard” club lengths. That is, the listed club lengths are recommended for golfers of average height. However, golf clubs having extended length shafts and shortened length shafts are also widely available for taller golfers and shorter golfers, respectively. Extended shaft lengths are typically 0.5 inches longer as compared to the standard shaft length for a club having the same loft angle LA, while shortened shaft lengths are typically 0.5 inches shorter as compared to the standard shaft length for a club having the same loft angle LA. It should be appreciated that the principles of the present embodiments are readily adaptable to extended and shortened shaft lengths by adjusting the club lengths listed in Table 1 by ±0.5 inches.

In Table 1, the hosel length HL corresponds to HL of FIG. 2, and decreases in increments of 0.125 inches for every 4° increase in loft angle LA. The bore length BL corresponds to BL of FIG. 2, and is constant throughout the set at 0.354 inches. The desired standard club length CL corresponds to CL of FIG. 2, and also decreases in increments of 0.125 inches for every 4° increase in loft angle LA. With these above dimensions, the shaft length SL is able to be maintained at a constant 33.28 inches throughout the set. In this manner, a single shaft can be sequentially secured to each of the eight club heads in the set during a fitting process to enable the golfer being fitted to try club heads having eight different loft angles LA without needing multiple shafts to achieve the desired club length CL for each loft angle LA. Essentially, by varying the hosel length HL from club head to club head, the shaft length SL can be kept constant to achieve the desired club length CL for each loft angle LA.

The above dimensions are not to be construed as limiting, as different manufacturers may adhere to their own standards for determining club length. For example, the dimensions in Table 1 may vary by ±⅛″, ±¼″, ±½″, or any other value.

Under the prior art method of golf club fitting, there might not be a direct correlation between the hosel length HL and the club length CL. In other words, by maintaining a constant difference between CL and HL throughout the set as shown in Table 1, a constant shaft length SL may be used to achieve the plurality of incremental club lengths CL shown in Table 1.

With reference to FIG. 2, this concept can be expressed using the equation for the club length CL as follows:

CL=SL+HL,   (2)

where SL is the shaft length and HL is the hosel length. Another way of expressing Equation (2) is to subtract HL from each side. That is,

CL−HL=SL   (2)

Thus, a constant differential between CL and HL across wedges of varying loft angle LA maintains a constant SL. Expressed mathematically: SL=CL_PW−HL_PW=CL_GW−HL_GW=CL_LW−HL_LW, etc. This relationship allows the use of one shaft for each of the standard club lengths. In a similar manner, the “Standard length plus 0.5 inches” extended shaft can be reduced to one shaft across the set of wedges, and the “Standard length minus 0.5 inches” shortened shaft can also be reduced to one shaft across the set of wedges. Thus, only three shafts are needed for each brand for each shaft stiffness.

The following example provides additional illustration of how the present embodiments achieve advantages over the prior art. In this example, the following assumptions are made:

• • There are three wedge club heads that are to be fitted: (1) a 46° PW, (2) a 50° GW, and (3) a 58° LW.
  • Each club head can be fitted with either a Brand X shaft or a Brand Y shaft.
  • For the 46° PW, the standard club length CL is 35.5 inches. However, the standard club length may be increased or decreased by 0.5 inches for customization purposes. The standard club length CL may thus be represented as 35.5±0.5 inches. Similarly, for the 50° GW, the standard club length is 35.375±0.5 inches, and for the 58° LW, the standard club length is 35.125±0.5 inches.
  • For each club length, three different shaft stiffnesses, or “flexes,” are available: (1) A-flex, (2) R-flex, and (3) S-flex.

Under the above assumptions, and using the Equation (1), which is described above under the heading “BACKGROUND,”

S=Σ _i=1 ⁿ B·CL·SL,   (1)

where S is the total number of shafts needed, n represents the number of club heads with different wedge lofts offered, B represents the number of brands offered, CL represents the number of club lengths offered, and SL represents the number of stiffness levels offered, the prior art method requires 54 different shafts to provide a full range of customizable shaft options for the three wedge club heads: 54=Σ₁³2·3·3. Essentially, each shaft configuration requires its own shaft, which burdens the golf club fitting specialist, who must transport each of those 54 shafts to each retail fitting site just to fit three wedge club heads to each golfer.

Using the system of the present embodiments, only 18 shafts are required to achieve each of the club lengths under the above assumptions. That is, instead of needing S=Σ_i=1ⁿB·CL·SL shafts, the number of shafts required (denoted as S₂) can be expressed as S₂=B·CL·SL. Notably, no summation is needed for each additional wedge club head. Thus, the total number of shafts needed is reduced by ⅔, from 54 to 18. The reduction in the number of shafts needed becomes even more significant as the number of club heads in the calculation increases. The present embodiments thus create advantages where storage space for club heads and shafts is limited, such as with a portable fitting cart, or even with a fixed fitting display in a retail store where floor space may be limited.

Another advantageous feature of the present embodiments is that the number of shafts needed to fit a given number of loft angles does not change as the number of loft angles increases. For example, adding another loft angle to a given fitting does not require any additional shafts when the number of brand options, the number of club length options, and the number of shaft stiffness options are unchanged. Whereas under the prior art method, each additional club head added to the fitting requires another 18 shafts (where the number of brands options is two, the number of club length options is three, and the number of stiffness options is three, as in the above example).

In certain embodiments, across a set of wedges the club length CL may decrease by a constant length decrement D_L corresponding to a given loft angle LA increment I_LA. For example, for a loft angle LA increment I_LA of 4° the relationship of club length for a 46° PW with respect to a 50° GW may be expressed as:

CL ₅₀ =CL ₄₆ −D _L,   (3)

where CL₅₀ is the club length of the 50° GW, CL₄₆ is the club length of the 46° PW, and D_L is the length decrement between the PW and the GW.

The length decrement D_L can also be applied across hosel lengths. For example, for a loft angle LA increment I_LA of 4° the relationship of hosel length for a 46° PW with respect to a 50° GW may be expressed as:

HL ₅₀ =HI ₄₆ −D _L.   (4)

With reference to Table 1 above, in the illustrated embodiment D_L equals 0.125 inches for every loft angle LA increment I_LA of 4°. Accordingly, given a 35.5 inch standard club length for a 46° PW, a 50° GW would have a standard club length of 35.375 inches. This relationship holds across extended club lengths and shortened club lengths. Accordingly, given an extended club length of 36 inches for a 46° PW (35.5+0.5 inches), a 50° GW would have an extended club length of 35.875 inches (35.375+0.5 inches).

The D_L of 0.125 inches in Table 1 is merely one example. In alternative embodiments, D_L may have any other suitable value, such as, for example, 0.25 inches, 0.5 inches, etc.

In some embodiments, the length decrement D_L may correlate to a total length decrease D_MAX. In one example, D_MAX=D_L×N, where N is the number of times D_L must be incremented/decremented to arrive at the difference in length between the lowest lofted wedge and the highest lofted wedge. In the embodiment of Table 1, D_max=D_L×3=0.375 inches. In some embodiments, D_max is subject to a constraint, in which, D_max cannot exceed the hosel length HL of the highest lofted wedge in the set. For example, if the highest lofted wedge in the set is a 58° SW, D_max≦HL_SW.

In the present embodiments, with the relationships and constraints discussed above, various hosel lengths HL can be determined for each wedge in a set so that a given constant shaft length SL can be mated with any of the club heads in the set to produce the desired club length CL for any loft angle LA. In some embodiments, the hosel length HL may be correlated with the loft angle LA. For example, as shown in the graph of FIG. 3, as the loft angle LA increases, the hosel length HL decreases. Furthermore, the rate of change at which the hosel length HL decreases per unit change in loft angle LA is constant in FIG. 3, and can be represented as the slope S of the line L in FIG. 3, where

$S=\frac{\Delta HL}{\Delta LA},$

or the rate of change of hosel length HL divided by the rate of change of loft angle LA. Expressed another way:

(HL₁−HL₂)=S*(LA₂−LA₁),   (5)

where HL₁ and HL₂ represent the hosel lengths HL of two different wedges, and LA₁ and LA₂ represent the loft angles LA of the respective wedges. For example, S may be between 0.025 inches/degree and 0.035 inches/degree. In the embodiment of FIG. 3, 5 is about 0.03125 inches/degree.

Equation (5) relates the hosel lengths HL and loft angles LA of various wedges. With any given wedge, however, a relationship between its hosel length HL and loft angle LA may also exist. For instance, in some embodiments, a theoretical HL₀ at zero degree loft angle can be extrapolated from the graph of FIG. 3 to be 3.72 inches. By using this theoretical HL₀, the expression for correlating loft angle LA to hosel length HL (HL_LA) of a wedge of any loft angle LA may be determined as:

HL _LA=3.72 in−(0.03125inches/degree)*LA.   (6)

In one or more embodiments, HL_LA can be broadly expressed as:

3.66 inches−(0.03125 inches/degree)*LA≦HL_LA<3.78 inches−(0.03125 inches/degree)*LA.   (7)

In some embodiments, HL_LA can be expressed according to:

3.70 inches−(0.03125 inches/degree)*LA≦HL_LA≦3.74 inches−(0.03125 inches/degree)*LA.   (8)

Expressions (7) and (8) are supported by Table 2 below and the graph of FIG. 4. As further shown in Table 2, the maximum hosel length of a set HL_MAX is equal to the hosel length of the lowest lofted club in the golf club fitting system. In the example shown in Table 2, the 48° loft angle LA corresponds to HL_MAX.

TABLE 2
Loft Angle (LA)	Hosel Length (HL)	Lower Boundary	Upper Boundary
48°	2.22″	2.16″	2.28″
52°	2.095″	2.035″	2.155″
56°	1.97″	1.91″	2.03″
60°	1.845″	1.785″	1.905″

FIGS. 5-8 illustrate one embodiment of a system for varying the overall length of golf clubs for use in a process for fitting golf clubs to a golfer. FIG. 5 illustrates a first or body element 50 of the length-varying mechanism, which is fixed to and extends from the heel 14 of the golf club head 12 of the reference club 10 (see FIG. 1). FIG. 6 illustrates a second or sleeve element 52 that is configured to engage with the body element 50. FIGS. 7 and 8 illustrate the body and sleeve elements 50, 52 engaged with one another.

With reference to FIG. 5, the body element 50 comprises a castellated annular base 51 that includes a pair of first upwardly-extending diametrically-opposed tabs 54 and a pair of second upwardly-extending diametrically-opposed tabs 56. The first tabs 54 are measurably longer (axially) than the second tabs 56, and they are advantageously offset from them by about 90 degrees around the perimeter of the base 51. With reference to FIG. 6, the sleeve element 52 includes an annular collar 53 having a tapered upper portion 57a and a cylindrical, castellated lower portion 57b that is complementary with the castellated annular base 51 of the body element 50. The lower portion 57b defines a pair of first diametrically-opposed slots 58 and a pair of second diametrically-opposed slots 60 that are located to receive the tabs 54, 56 on the body element 50. The first slots 58 have a depth that corresponds approximately to the axial length of the longer first tabs 54, while the second slots 60 have a depth corresponding approximately to the axial length of the shorter second tabs 56. The sleeve element 52 further includes a downwardly-depending plug 62, around the upper end of which the lower portion 57b is concentrically disposed. The body element 50 includes a bore 64 configured to receive the plug 62, while the upper portion 57a of the sleeve element 52 includes a tubular passage 66 configured to receive a golf club shaft (not shown).

As described above and as shown in the drawings, the first tabs 54 have a greater axial length or height than the second tabs 56, and the first slots 58 have a greater depth than the second slots 60. Thus, when the plug 62 of the sleeve element 52 is inserted into the bore 64 of the body element 50 in a first rotational orientation illustrated in FIG. 7, the first tabs 54 on the body element 50 seat in the first slots 58 in the sleeve element 52, and the second tabs 56 on the body element 50 seat in the second slots 60 in the sleeve element 52. This configuration enables the sleeve element 52 to be inserted to a first distance within the body element 50. With reference to FIG. 8, when the sleeve element 52 is rotated to a second rotational orientation 90° displaced from the first rotational orientation shown in FIG. 7, the first tabs 54 on the body element 50 are received within the second slots 60 in the sleeve element 52. Because the second slots 60 are shallower than the first slots 58, the sleeve element 52 does not extend as far into the body element 50 as it does in the first rotational orientation of FIG. 7. The configuration of FIG. 8 thus results in a greater overall club length, because the effective length of the hosel has been increased by approximately the difference in axial length between the first tabs 54 and the second tabs 56. In this embodiment, as in any of the present embodiments, the variance in overall club length may be about ⅛″, about ¼″, or any other value. While not shown, a securement mechanism, such as a set screw, may be used to removably secure the body element 50 and the sleeve element 52 to one another.

FIGS. 9-11 illustrate another embodiment of a system for varying the overall length of golf clubs for use in a process for fitting golf clubs to a golfer. This embodiment includes a tubular adapter 70 having a radial protrusion 72. With reference to FIG. 11, the adapter 70 includes a tubular passage 74 configured to receive the end of a reference golf club shaft 75. A reference club head 12′ includes a hollow, hosel-like sleeve 76 extending upwardly from its heel, the sleeve 76 defining a bore 78 configured to receive the adapter 70. The sleeve 76 also includes a slot 80 in a sidewall thereof having first and second longitudinally spaced detents 82, 84. The protrusion 72 is configured to be seated in either of the detents 82, 84 to define first and second club lengths, respectively. In FIG. 9, the protrusion 72 is seated in the first detent 82 to provide a first selectable club length, and in FIG. 10 the protrusion 72 is seated in the second detent 84 to provide a second selectable club length. By seating the protrusion 72 in one or the other of the detents 82, 84, the overall club length can be varied between the first club length and the second length, because the extent to which the shaft 75 extends into the socket 78 defined by the sleeve 76 is varied. With reference to FIG. 11, a securement mechanism, such as one or more set screws 86, may be used to removably secure the adapter 70 to the shaft 75, and to the sleeve 76. Further, while two detents are shown in FIGS. 9-11, any number of detents may be provided.

The embodiment of FIGS. 9-11 is particularly useful when adjusting the overall club length for taller golfers and/or shorter golfers. As discussed above, extended club lengths for taller golfers are typically 0.5 inches longer as compared to the standard club length for a club having the same loft angle LA, while shortened club lengths for shorter golfers are typically 0.5 inches shorter as compared to the standard club length for a club having the same loft angle LA. Thus, in the embodiment of FIGS. 9-11 the first and second detents 82, 84 may, for example, be spaced by 0.5 inches. If the first detent 82 provides a proper club length for a golfer of average height, then the second detent 84 would provide a proper club length for a taller golfer. Similarly, if the second detent 84 provides a proper club length for a golfer of average height, then the first detent 82 would provide a proper club length for a shorter golfer. In an embodiment of the club head 12′ having three detents all spaced from one another by 0.5 inches, a single shaft and club head could be used to fit shorter golfers, golfers of average height, and taller golfers.

In another embodiment (not shown) the embodiment of FIGS. 9-11 may be modified to omit the adapter 70. In such an embodiment, the golf club shaft may include a radial protrusion configured to seat within one or more detents in the sleeve of the club head.

FIG. 12 illustrates another embodiment of a system for varying the overall length of golf clubs for use in a process for fitting golf clubs to a golfer. This embodiment includes a club shaft 90 having a plurality of longitudinally spaced openings 92, and a plug 94 selectively engageable with each of the openings 92. A location of the plug 94 along the shaft 90 determines an extent to which the shaft 90 may extend into a bore 96 defined in a hollow, hosel-like sleeve 98. Thus, by varying a location of the plug 94 along the shaft 90, e.g. by selecting which of the openings 92 the plug 94 engages, the overall length of the golf club can be varied. The plug 94 may, in some embodiments, comprise a threaded member, such as a bolt or a screw, and the openings 92 may include internal threads to matingly receive the plug 94. A set screw or other securement mechanism (not shown) may removably secure the shaft 90 at a selected position within the bore 96. In the illustrated embodiment, three openings 92 are shown, but in alternative embodiments any number of openings 92 may be provided.

FIGS. 13A-13B illustrate another embodiment of a system for varying the overall length of golf clubs for use in a process for fitting golf clubs to a golfer. This embodiment includes one or more plugs that are inserted into a bore 96′ defined by a hollow, hosel-like sleeve 98′ on the club head prior to the insertion of a club shaft 106 into the bore 96′, in order to limit the extent to which the shaft 106 may extend into the bore 96′. For example, FIG. 13A illustrates a set of plugs 100, 102, 104 having varying thicknesses. The illustrated set includes three plugs, but alternative sets may include one or two plugs, or any number of plugs greater than three. In the illustrated example set, a first plug 100 has a first thickness, T₁, a second plug 102 has a second thickness, T₂, and a third plug 104 has a third thickness, T₃. Depending upon which of the plugs 100, 102, 104 is inserted in the bore 96′ prior to insertion of the shaft 106, the overall length of the golf club will vary. For example, inserting the first plug 100 provides a relatively shorter club length, while inserting the second plug 102 or third plug 104 provides a relatively longer club length. FIG. 13B illustrates a configuration in which the second plug 102 has been inserted into the bore 96′ of the sleeve 98′ prior to insertion of the shaft 106.

In another embodiment, a set of plugs may include one or more plugs of uniform thickness. By varying the number of plugs inserted into the bore hole prior to the shaft, the overall length of the golf club will vary. For example, inserting one of the first plugs 100 provides a relatively shorter club length, while inserting two or more of the first plugs 100 provides a relatively longer club length. FIG. 13C illustrates two of the first plugs 100 inserted into the bore 96′ of the hosel-like sleeve 98′ prior to insertion of the shaft 106 into the sleeve 98′.

FIGS. 14A-14B illustrate another embodiment of a system for varying the overall length of golf clubs for use in a process for fitting golf clubs to a golfer. This embodiment includes removable tubular adapters having different bottom wall thicknesses. For example, FIG. 14A illustrates a first adapter 108 that is externally dimensioned to fit snugly into a bore 96″ defined in a hosel-like sleeve 98″ and that defines an interior passage 109 dimensioned to receive the end of a club shaft 106. The first adapter 108 has a bottom wall 110 with a first, relatively small thickness T₁. FIG. 14B illustrates a second adapter 108′ that is identical to the first adapter 108, but with a bottom wall 110′ having a second thickness T₂ that is greater than the first thickness T₁. The adapters 108, 108′ limit the extent to which the shaft 106 extends into the bore 96″ in the hosel-like sleeve 98″. Thus, the first adapter 108 provides a relatively shorter club length, while the second adapter 108′ provides a relatively longer club length.

FIGS. 15A-15B illustrates another embodiment of a system for varying the overall length of golf clubs for use in a process for fitting golf clubs to a golfer. This embodiment includes a shaft 112 having a plurality of telescoping segments 114, 116, 118, 120. For example, in FIG. 15A a first segment 114 is in an extended position with respect to a second segment 116, while the second segment 116 and a third segment 118 are in a retracted position with respect to a fourth segment 120, resulting in a relatively shorter overall club length. In FIG. 15B, by contrast, all of the segments 114, 116, 118, 120 are in an extended position, resulting in a relatively longer overall club length.

As the foregoing description illustrates, the present embodiments enable a single shaft to be used to fit multiple club heads having different loft angles while simultaneously varying the overall club length for club heads having different loft angles. In some embodiments, this advantage is accomplished by varying a hosel length of the club. Varying the hosel length may, in some embodiments, be accomplished by changing the effective length of a bore in a hosel-like sleeve extending from the heel of the club head. In other embodiments, varying the hosel length may be accomplished by varying an extent to which the shaft extends into the bore of the hosel-like sleeve.

In accordance with the present embodiments, a system for fitting golf clubs to a golfer comprises a plurality of golf club heads and a single golf club shaft, wherein the system is configurable to achieve a plurality of golf club lengths using only the single golf club shaft. In certain embodiments, the foregoing advantage is achieved by varying a hosel length of the golf club. In other embodiments, the foregoing advantage is achieved by varying an extent to which the single golf club shaft extends into a hosel-like sleeve on each golf club head. In such embodiments, a golf club fitting professional is able to present a golfer with a range of golf club lengths across a range of loft angles using only a single golf club shaft.

Also in accordance with the present embodiments, a plurality of golf club heads is configured to be mated with a single golf club shaft such that an overall golf club length is variable. In such embodiments, the plurality of golf club heads may include a variable bore length in a hosel-like sleeve on each club head, such that the golf club shaft may extend into the sleeve of each of the golf club heads by a varying extent. In other such embodiments, the plurality of golf club heads and/or the golf club shaft may include an adapter that selectively limits an extent to which the golf club shaft may extend into the hosel-like sleeve of each of the golf club heads.

FIG. 16 illustrates a process 1600, in accordance with this disclosure, for fitting a set of golf clubs to a golfer using only a single golf club shaft. A “set,” as defined herein, may include any number of golf clubs. The process 1600 may comprise securing a first golf club head to a shaft such that the overall club length is equal to a first length (B1602), disengaging the first golf club head from the shaft (B1604), and securing a second golf club head to the shaft such that the overall club length is equal to a second length, wherein the first and second overall club lengths are different (B1606). Further, a loft angle of the first golf club head may differ from a loft angle of the second golf club head.

In accordance with this disclosure, a process for making a set of golf clubs based on a fitting process may comprise any of the fitting processes described herein, and further comprising any of forging, molding, machining, milling, etching, etc. of golf club heads for the set of golf clubs, and/or fitting the golf club heads to golf club shafts.

Certain of the present embodiments comprise varying an overall club length based on loft angles of a plurality of club heads, without varying the length of a reference shaft configured to be connected to each of the plurality of club heads. Others of the present embodiments comprise varying hosel lengths of a plurality of golf club heads in order to vary the overall club length without varying the length of a reference shaft configured to be connected to each of the plurality of club heads.

In another of the present embodiments, an overall length of a plurality of golf clubs may remain constant, while a grip on the shaft may include markings or indicia that indicate where a golfer should grasp the grip depending upon which of a plurality of golf club heads is attached to the shaft so as to effectively vary the length of each of the clubs. For example, FIG. 17 illustrates a grip 122 having a plurality of longitudinally spaced markings 124 that indicate where the lower extent of a golfer's lower hand should be located, depending upon the loft angle of the club head (not shown) attached to the shaft 126. For a higher lofted club head, the golfer should align his or her lower hand with a lower one of the markings 124 (“choke up”), and for a lower lofted club head, the golfer should align his or her lower hand with a higher one of the markings 124 (“choke down”).

In another of the present embodiments, an overall length of a plurality of golf clubs may be varied using a single shaft by removing a first grip having a first grip length from the shaft and securing a second grip having a second grip length to the shaft, wherein the first and second grip lengths differ. For example, with reference to FIG. 18A, when a lesser lofted club head is attached to a shaft 128, a first grip 130 having a relatively long length may be secured to the shaft 128, and when a greater lofted club head is attached to the shaft 128, a second grip 132 having a relatively short length may be secured to the shaft 128. Engagement between the grips 130, 132 and the shaft 128 may be via any conventional means, such as threads, a set screw, etc.

While certain embodiments have been described herein, one of ordinary skill in the art will recognize that the above principles can be applied to other golf club types and mixed golf club types. Furthermore, the construction of the wedge(s) shown in the figures has been simplified and/or shown schematically for the sake of brevity and clarity, and should be not construed as limiting the claims. Indeed, the above described concepts are equally applicable to golf clubs having shaft sleeves, etc.

Claims

1. A golf club fitting system, comprising: a golf club head including a body portion having a first tubular passage and a plurality of first castellations arranged about an upper end of the first tubular passage, the first castellations extending upward; anda collar portion including a second tubular passage configured to receive a golf club shaft having a shaft length, and further including a plurality of second castellations arranged about a lower end thereof, the second castellations extending downward;wherein the first and second castellations seat with one another in a first configuration to define, in combination with the golf club shaft having the shaft length, a first overall golf club length;wherein the first and second castellations seat with one another in a second configuration to define, in combination with the golf club shaft having the shaft length, a second overall golf club length, wherein the first and second overall golf club lengths are different.

2. The golf club fitting system of claim 1, wherein when the first and second castellations seat with one another in the first configuration, the collar portion defines a first rotational orientation with respect to the body portion, and when the first and second castellations seat with one another in the second configuration, the collar portion defines a second rotational orientation with respect to the body portion.

3. The golf club fitting system of claim 1, wherein the first castellations comprise a pair of first upwardly-extending diametrically-opposed tabs, and a pair of second upwardly-extending diametrically-opposed tabs.

4. The golf club fitting system of claim 3, wherein the first tabs are measurably longer axially than the second tabs.

5. The golf club fitting system of claim 3, wherein the first tabs are offset from the second tabs by about 90° around the perimeter of the first tubular passage.

6. The golf club fitting system of claim 3, wherein the second castellations comprise a pair of first diametrically-opposed slots configured to receive the first tabs and a pair of second diametrically-opposed slots configured to receive the second tabs.

7. The golf club fitting system of claim 1, further comprising a plug portion extending from the collar portion, wherein the first tubular passage of the body portion receives the plug portion.

8. A golf club fitting system, comprising: a golf club head including a hosel having a first tubular passage, the hosel having a slot in a sidewall thereof defining a plurality of detents; anda tubular adapter having a radial protrusion, the adapter including a second tubular passage configured to receive a golf club shaft having a shaft length;wherein the radial protrusion is configured to be seated in any of the detents in the slot to vary an extent to which the adapter and the golf club shaft having the shaft length extend into the first tubular passage to thereby vary an overall golf club length using the golf club shaft having the shaft length.

9. The golf club fitting system of claim 8, wherein the slot defines two detents.

10. The golf club fitting system of claim 8, further comprising a securement mechanism configured to removably secure the adapter to the golf club shaft and to the golf club head.

11. The golf club fitting system of claim 10, wherein the securement mechanism comprises one or more set screws.

12. A method for fitting a set of golf clubs to a golfer, the method comprising: securing a first golf club head to a golf club shaft such that the golf club shaft extends a first distance into the first golf club head;removing the first golf club head from the golf club shaft; andsecuring a second golf club head to the golf club shaft such that the golf club shaft extends a second distance into the second golf club head;wherein the first and second distances are different; andwherein the first and second distances respectively correspond to first and second rotational orientations of the golf club heads to the golf club shaft.

13. The method of claim 12, wherein the first rotational orientation of the golf club heads to the golf club shaft is offset by about 90° from the second rotational orientation of the golf club heads to the golf club shaft.

14. A golf club fitting system, comprising: at least two golf club heads; anda golf club shaft;wherein the system is configurable to provide a plurality of golf club lengths using only the golf club heads and the golf club shaft; andwherein providing the plurality of golf club lengths comprises varying an extent to which the golf club shaft extends into the golf club heads.

15. The golf club fitting system of claim 14, wherein providing the plurality of golf club lengths comprises varying a hosel length of a golf club formed from the golf club heads and the golf club shaft.

16. The golf club fitting system of claim 14, further comprising a plurality of hosel-like sleeves having variable bore lengths, wherein the sleeves are alternately receivable within a bore in each of the golf club heads.

17. The golf club fitting system of claim 14, further comprising a plurality of adapters, wherein the adapters are receivable within a bore in each of the golf club heads to selectively limit an extent to which the golf club shaft may extend into each of the golf club heads.