Systems and methods for fitting golf clubs

Abstract

A system for fitting golf clubs to golfers that enables an overall club length to be varied without varying a length of a 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.

Claims

1. A golf club fitting system, comprising: a plurality of wedge-type golf club heads including: 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 LA.sub.1; and a first hosel length HL.sub.1; 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 LA.sub.2 greater than the first loft angle LA.sub.1, a difference between the second loft angle and the first loft angle being no more than 15°; and a second hosel length HL.sub.2 less than the first hosel length HL.sub.1 by at least 0.340 inches; 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 LA.sub.3 greater than the first loft angle and less than the second loft angle; and a third hosel length HL.sub.3 less than the first hosel length HL.sub.1 and greater than the second hosel length HL.sub.2; and a fourth club head having: a fourth striking face; a fourth main body; a fourth hosel extending from the fourth main body; a fourth loft angle greater than the first and third loft angles and less than the second loft angle; and a fourth hosel length HL.sub.4 less than the first and third hosel lengths HL.sub.1 and HL.sub.3 and greater than the second hosel length HL.sub.2; a plurality of shafts each having the same shaft length, at least some of the plurality of shafts differing in brand identification and at least some of the plurality of shafts differing in shaft stiffness; and a container configured to store the plurality of wedge-type golf club heads and the plurality of shafts.

2. The golf club fitting system of claim 1, wherein (i) the difference D.sub.13 between the first hosel length HL.sub.1 and the third hosel length HL.sub.3, (ii) the difference D.sub.34 between the third hosel length HL.sub.3 and the fourth hosel length HL.sub.4, and (iii) the difference D.sub.42 between the fourth hosel length HL.sub.4 and the second hosel length HL.sub.2 are substantially equal to each other.

3. The golf club fitting system of claim 2, wherein the differences D.sub.13, D.sub.34, and D.sub.42 substantially equal 0.125 in.

4. The golf club fitting system of claim 3, wherein (i) the difference between the first loft angle and the third loft angle; (ii) the difference between the third loft angle and the fourth loft angle; and (iii) the difference between the fourth loft angle and the second loft angle substantially equal 4°.

5. The golf club fitting system of claim 1, wherein: the third loft angle is greater than the first loft angle by no more than 5°; and the third hosel length HL.sub.3 is less than the first hosel length HL.sub.1 by at least 0.120 inches.

6. The golf club fitting system of claim 1, wherein: the first and second golf club heads satisfy the following:
(HL.sub.1−HL.sub.2)=R*(LA.sub.2−LA.sub.1); and R is within the range of 0.025 in./° to 0.035 in./°.

7. The golf club fitting system of claim 1, wherein the first, second and third golf club heads are respectively configured to satisfy the following:
3.66 in.−(0.03125 in./°)*LA.sub.1≦HL.sub.1≦3.78 in.−(0.03125 in./°)*LA.sub.1;
3.66 in.−(0.03125 in./°)*LA.sub.2≦HL.sub.2≦3.78 in.−(0.03125 in./°)*LA.sub.2; and
3.66 in.−(0.03125 in./°)*LA.sub.3≦HL.sub.3≦3.78 in.−(0.03125 in./°)*LA.sub.3.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) 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:

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

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

(4) FIG. 3 is a graph of hosel length versus loft angle for use in accordance with an embodiment of this disclosure; and

(5) FIG. 4 is a graph of hosel length versus loft angle for use in accordance with another embodiment of this disclosure.

DETAILED DESCRIPTION

(6) 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 need to be carried by the golf club fitting specialist. And, because a golfer typically only carries a few wedges (e.g., 2 or 3 wedges) as opposed to a more substantial number of irons (e.g., 6+ iron clubs) in his or her golf bag, the below description works particularly well with wedge fitting.

(7) FIG. 2 illustrates a golf club fitting apparatus that includes a reference club 10 comprising the components of a conventional golf club; in this specific example, 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 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).

(8) The reference club 10 is used in conjunction with a measurement device to measure golf club dimensions for fitting a golf club 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; alternatively in cm and mm). 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 scale 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.

(9) 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). 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). In one embodiment, the bore length BL may be measured along the shaft axis A when the shaft 14 is inserted into the bore 18 of the hosel 16. In another embodiment, the bore length BL may be pre-measured before the shaft 14 is inserted into the hosel bore 18.

(10) 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 line C).

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

Embodiment 1

(12) In one embodiment, provided is a line of eight wedge club heads of a set (e.g., 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). By configuring the hosel length HL of each club head, a single shaft can be used interchangeably between each wedge of the set in order to achieve the desired club length CL.

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

(14) TABLE-US-00001 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

(15) The hosel length HL corresponds to HL of FIG. 2, and decreases in a 0.125 in. increment for every 4° increase in loft. The bore length BL corresponds to BL of FIG. 2, and is constant throughout the set at 0.354 in. The desired standard club length CL corresponds to CL of FIG. 2, and also decreases in a 0.125 in. increment for every 4° increase in loft. With these above dimensions, the shaft length SL is able to be maintained at a constant 33.28 in. throughout the set. In this manner, one shaft can be removably inserted into each of the eight club heads during a fitting process. 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.

(16) 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 achieved for a standard length club CL. Similar principles may be applied to extended length shaft lengths and shortened shaft lengths (e.g., ±0.5 in.)

Embodiment 2

(17) Assumptions:

(18) A. There are three wedge club heads that are to be fitted: (1) a 46° pitching wedge, (2) a 50° gap wedge, and (3) a 58° lob wedge).

(19) B. Each club head can be fitted with either a Brand X shaft or a Brand Y shaft.

(20) C. For the 46° pitching wedge club head, the standard club length CL is 35.5 in. However, the standard club length may be increased or decreased by 0.5 in. for customization purposes. Essentially, the club length CL may be represented as 35.5±0.5 in. Similarly, for the 50° gap wedge club head, the available club lengths are 35.375±0.5 in. For the 58° lob wedge club head, the available club lengths are 35.125±0.5 in.

(21) D. For each club length, three different degrees of stiffness or “flexes” are available: (1) A-flex, (2) R-flex, and (3) S-flex.

(22) Under this set of assumptions (which are generally abbreviated for the sake of clarity and brevity), and using the above equation (1), 54 different shafts are required to provide a full library of customizable shaft options for the three wedge club heads under a prior art fitting method. Essentially, each shaft configuration requires its own shaft.

(23) The proposed solution aims to create a system where the number of shafts required to achieve each of the club lengths in the assumptions above is reduced to only 18. Stated differently, instead of needing S=Σ.sub.i=1.sup.nB.Math.CL.Math.SL, the number of shafts required (denoted as S2) can be expressed as B.Math.CL.Math.SL. Notably, no summation is needed for each additional wedge club head. In this, case, the total number of shafts can be reduced by ⅔, i.e., from 54 to 18. Where a large number of club heads are in the library, the reduction in the number of shafts becomes even more significant. Furthermore, the advantage becomes even more magnified where the storage space is very limited (e.g., a fitting cart or fitting display).

(24) Different club characteristics such as (1) bore length BL, (2) hosel length HL, and (3) shaft length SL, are defined as shown in FIG. 2. Generally, the equation for the club length CL is as follows:
CL=SL+HL,  (2)

(25) where SL is the shaft length and HL is the hosel length.

(26) To achieve the reduction in the total number of shafts, a constant differential between club length and hosel length throughout the different wedges may be maintained. That is, CL.sub.PW−HL.sub.PW=CL.sub.GW−HL.sub.GW=CL.sub.LW−HL.sub.LW. By ensuring this relationship, the usage of one shaft for each of the standard club lengths is guaranteed. In a similar manner, the “Standard length+0.5 in.” extended shaft can be reduced to one shaft across the wedges, and the “Standard length−0.5 in.” shortened shaft can also be reduced to one shaft across the wedges. Thus, only three shafts are needed for each brand at each shaft stiffness, enabling the reduction to 18 shafts using the novel proposed method from 54 shafts using the prior art method.

(27) Furthermore, another advantageous feature of the present invention is that no additional shafts are needed even where additional wedges are added to the library. For example, adding a 54° sand wedge does not require any additional shafts when the brands supplied, the shaft stiffness options. etc. are unchanged. With respect to Example 1, under the prior art method, each additional wedge added to the library would require another 18 shafts.

(28) In one embodiment, with respect to a standard club length across several different wedge lofts, the standard club length may decrease by a constant length decrease increment D, proportional to an increase in loft. That is, the relationship of standard club length of a 46° pitching wedge with respect to a 50° gap wedge may be expressed as:
CL.sub.50=CL.sub.46−D,  (3)

(29) where D is the length decrease increment.

(30) Similarly, the length decrease increment D should also be applied to the hosel lengths:
HL50=HL46−D.  (4)

(31) In one embodiment, D is set at 0.125 in. Accordingly, given a 35.5 in. standard club length for a 46° pitching wedge, the 50° gap wedge would have a 35.375 in. standard club length. This relationship holds across extended club lengths and shortened club lengths. So, given an extended club length of 36 in. for a 46° pitching wedge (35.5+0.5 in.), the 50° gap wedge would be 35.875 in. (35.375+0.5 in.).

(32) In one or more embodiments, the 0.125 in. differential is customizable (e.g., 0.25 in., 0.5 in., etc.).

(33) Also, in one or more embodiments, the length decrease increment D correlates to a total decrease increment D.sub.max. In one or more embodiments. D.sub.max=D×(N−1), where N is the number of wedges in the set. In Embodiment 1, D.sub.max=D×M, where M is the number of times the length decrease increment D is decremented throughout the set (M=3 in Embodiment 1). Stated differently, Embodiment 1 has a D.sub.max=0.375 in. In one or more embodiments, D.sub.max is subject to a constraint. Namely. D.sub.max cannot exceed the hosel length HL of the highest lofted wedge (e.g., a 58° SW if the 58° SW is the highest lofted wedge in the set). In other words, in this example, D.sub.max≦HL.sub.SW.

(34) So, with the relationships and constraints discussed above, the various hosel lengths HL can be determined for each wedge of the set, corresponding to a particular shaft length SL. Notably, CL and BL are generally given and may be set accordingly.

Embodiment 3

(35) In one or more embodiments, the hosel length is correlated with the loft angle. As shown in the graph of FIG. 3, as the loft angle increases, the hosel length decreases.

(36) Furthermore, the factor or increment by which the hosel length decreases is constant when moving from a wedge of a first loft and the next two consecutive increasingly lofted wedges (e.g., moving from a 46° wedge to a 50° wedge to a 54° wedge). Indeed, this hosel length decrease increment can be represented as a rate of change R in hosel length per degree change in loft angle. For example, R may be between 0.025 in. and 0.0350 in. per degree. In this embodiment, R is 0.03125 in./degree.

(37) The relationship between the various differently lofted wedges of a set may satisfy:
(HL.sub.1−HL.sub.2)=R*(LA.sub.2−LA.sub.1),  (5)

(38) where HL.sub.1 and HL.sub.2 represent hosel lengths of the respective wedges, and LA.sub.1 and LA.sub.2 represent the loft angles of the respective wedges. As shown, the loft angle of each of the wedges differs from the loft angle of another wedge by at least 4°. However, other configurations are possible.

(39) The above expression relates the hosel length and loft angles of various wedges. With any given wedge, however, a relationship between its hosel length and loft angle may also exist. For instance, in one or more embodiments, a theoretical HL.sub.0 at zero degree loft can be extrapolated from the data of Embodiment 3 to be 3.72 in. By using this theoretical HL.sub.0, the expression for correlating loft angle to hosel length of a wedge of any loft angle LA may be determined as:
HL.sub.LA=3.72 in−(0.03125 in./°)*LA.  (6)

(40) In one or more embodiments. HL.sub.LA can be broadly expressed as:
3.66 in.−(0.03125 in./°)*LA≦HL.sub.LA≦3.78 in.−(0.03125 in./°)*LA.  (7)

(41) In one or more embodiments. HL.sub.LA can be expressed according to:
3.70 in.−(0.03125 in./°)*LA≦HL.sub.LA≦3.74 in.−(0.03125 in./°)*LA.  (8)

(42) Expressions (7) and (8) are supported by the following table (Table 2) and the graph of FIG. 4. The loft angle LA is shown in degrees, while the hosel length HL lower boundary and upper boundary are shown in inches. As further shown in Table 2, the maximum hosel length of a set HL.sub.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 club head with the 48° loft angle).

(43) TABLE-US-00002 TABLE 2 Loft Angle Hosel Length Lower Upper (LA) (HL) boundary 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

(44) While certain embodiments have been described herein, one of ordinary skill in the art will recognize that the above principles can still be applied to other correlated sets of golf clubs types or mixed golf club types. Furthermore, the construction of the wedge has been simplified 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.