DEVICE FOR ADJUSTING SERIES OF GOLF CLUBS AND SERIES OF GOLF CLUBS THUS ADJUSTED

Abstract

The invention relates to a method for adjusting a series of golf clubs each comprising a shaft, a head at the proximal end of the shaft and a grip at the distal end of the shaft; said method comprising the following steps: adjusting the mass of the head of each golf club and/or, adjusting the mass of the shaft near the distal end of the shaft, such that each golf club has a substantially identical moment of inertia; then adjusting the mass of the grip of each golf club and/or adjusting the mass of the shaft near the proximal end of the shaft, such that each golf club has a substantially identical swingweight. The invention also relates to a series of golf clubs adjusted using the method according to the invention.

Claims

1. A method for adjusting a series of golf clubs each comprising a shaft, a head at a proximal end of the shaft and a grip at a distal end of the shaft; said method comprising the following steps: adjusting the mass of the head of each golf club and/or adjusting the mass of the shaft of each golf club near the distal end of the shaft, such that each golf club has a substantially identical moment of inertia along an axis passing through the proximal end of the shaft; and adjusting the mass of the grip of each golf club and/or adjusting the mass of the shaft of each golf club near the proximal end of the shaft, such that each golf club has a substantially identical swingweight.

2. The adjusting method according to claim 1, further comprising adjusting the length of the shaft of each golf club and/or adjusting the lie angle of each golf club, such that each golf club has a substantially identical address position.

3. The adjusting method according to claim 1, wherein the adjustment of the mass of the head of each golf club is done by adding or removing at least one tip weight in the head.

4. The adjusting method according to claim 1, wherein the adjustment of the mass of the head of each golf club is done by adding or removing powder in the head.

5. The adjusting method according to claim 1, wherein the adjustment of the mass of the shaft of each golf club near the distal end of the shaft is done by adding or removing at least one tip weight in the shaft near the distal end of the shaft.

6. The adjusting method according to claim 1, wherein the adjustment of the mass of the grip of each golf club is done by replacing the grip with a grip having a different mass.

7. The adjusting method according to claim 1, wherein the adjustment of the mass of the grip of each golf club is done by adding or removing at least one tip weight in the grip.

8. The adjusting method according to claim 1, wherein the adjustment of the mass of the shaft of each golf club near the proximal end of the shaft is done by adding or removing at least tip weight in the shaft near the proximal end of the shaft.

9. A series of golf clubs adjusted using the method according to claim 1.

10. The series of golf clubs according to claim 9, wherein the head of each golf club comprises an iron or a wood.

11. A series of golf clubs, each comprising a shaft, a head at a proximal end of the shaft and a grip at a distal end of the shaft; wherein said series is adjusted using the following steps: adjusting the mass of the head of each golf club and/or adjusting the mass of the shaft of each golf club near the distal end of the shaft, such that each golf club has a substantially identical moment of inertia along an axis passing through the proximal end of the shaft; and adjusting the mass of the grip of each golf club and/or adjusting the mass of the shaft of each golf club near the proximal end of the shaft, such that each golf club has a substantially identical swingweight.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0029] FIG. 1 shows the swingweight scale as a function of the swingweight value obtained using formula [Math 1] or a swingweight scale.

[0030] FIG. 2 schematically illustrates a golf club.

[0031] FIG. 3 schematically illustrates a golf head comprising a tip weight.

[0032] FIG. 4 schematically illustrates the proximal end of a grip and a shaft in which a tip weight is inserted.

[0033] FIG. 5 schematically illustrates the address position (A), the length (L) and the lie angle (Li) of a golf club.

DETAILED DESCRIPTION OF THE INVENTION

[0034] FIG. 2 illustrates a golf club (1) comprising a shaft (2) connecting a head (3) to a grip (4). Each golf club from a series of golf clubs comprises these 3 elements.

[0035] As indicated above, in order to adjust a series of golf clubs such that each golf club has a substantially identical moment of inertia and a substantially identical swingweight, the masses are adjusted. Of course, one of the golf clubs serves as a reference. This club may not be subject to any adjustment or may be subject to an adjustment desired by the user.

[0036] First of all, the mass of the head of each golf club and/or the mass of the shaft of each golf club near the distal end of the shaft is adjusted, such that each golf club has a substantially identical moment of inertia. As illustrated in [FIG. 3], this adjustment can be done by adding a tip weight (5) into the head (3) of the golf club. Preferably, as illustrated, this tip weight is introduced at the end of the orifice serving to connect the shaft (2) and the head (3). According to one embodiment, the moment of inertia is typically set within a range of values from 1800 to 2800 kg.Math.cm.sup.2.

[0037] Once the moment of inertia is adjusted, the mass of the grip of each golf club and/or the mass of the shaft of each golf club near the proximal end of the shaft is adjusted, such that each golf club has a substantially identical swingweight. As illustrated in [FIG. 4], this adjustment can be done by adding a second tip weight (6) into the shaft (2) at the proximal end of the shaft under the grip (4). This adjustment of the swingweight is done with a constant moment of inertia. According to one embodiment, the swingweight is typically set within a range of swingweight values from 10 to 8, i.e. within a range of swingweight scale from C0 to D8.

[0038] At the end of the adjusting method, one therefore obtains a series of golf clubs all having a substantially identical moment of inertia and a substantially identical swingweight.

EXAMPLES

[0039] Calculation of the Swingweight

[0040] As an example, the swingweight can be calculated as follows (cf. Computing Heft, The Tutleman site, Oct. 8, 2018,

[0041] https://www.tutelman.com/golf/design/swingwt2.php):

[00001]$\begin{array}{cc}\mathrm{SW}=\frac{\mathrm{Lc}\left(T+\frac{S}{2}\right)-14.Math..Math.\left(T+S\right)-10G}{50}-124& \left[\mathrm{Math}.Math..Math.1\right]\end{array}$

where [0042] SW is the swingweight rounded to the closest unit; [0043] Lc is the length of the club (in inches); [0044] T is the weight of the Head of the club (in grams); [0045] S is the weight of the shaft (in grams); [0046] G is the weight of the grip (in grams).

[0047] Calculation of the Moment of Inertia

[0048] As an example, the moment of inertia can be calculated as follows (cf.

[0049] Computing Heft, The Tutleman site, Oct. 8, 2018, https://www.tutelman.com/golf/design/swingwt2.php):

[00002]$\begin{array}{cc}M.Math..Math.O.Math..Math.I={\mathrm{Lc}}^2\left(T+\frac{S}{3}\right)+10G& \left[\mathrm{Math}.Math..Math.2\right]\end{array}$

[0050] where [0051] Lc is the length of the club (in inches); [0052] T is the weight of the Head of the club (in grams); [0053] S is the weight of the shaft (in grams); [0054] G is the weight of the grip (in grams).

[0055] Calculation of the Influence of the Change in Weight of the Grip on the Swingweight and the Moment of Inertia.

[0056] Consider the example of a 5 iron with a length of 38 inches (Lc), whereof the weight of the head (T) is 254 grams, the weight of the shaft (S) is 90 grams and the weight of the grip (G) is 50 grams.

[0057] This iron has a swing value of 4 and a moment of inertia of 410,596 g.Math.inch.sup.2. According to the swingweight scale illustrated in [FIG. 1], this iron therefore has a swingweight of D4.

[0058] In the hypothesis of a change of grip, it is possible to calculate the influence of the use of a grip of 60 grams (or 10 grams more than the previous grip) on the swingweight and the moment of inertia of the iron.

[0059] With a grip of 60 grams, one obtains a swingweight of 2 and a moment of inertia of 410,696 g.Math.inch.sup.2. The swingweight of this iron is therefore henceforth D2 (cf. the swingweight scale in [FIG. 1]), which represents a very sensitive variation for a knowledgeable golf player, while the moment of inertia remains practically unchanged (variation of 2 per 10,000).

[0060] This shows that, in order to adjust the swingweight to a target value without changing the moment of inertia, it suffices to add weight to or remove it from the top of the shaft, near or on the grip, which is done easily by adding or removing tip plates in the top of the shaft or changing the grip. This method makes it possible to obtain a set of clubs all having a substantially identical swingweight and moment of inertia.

[0061] Adjustment of the Address Position

[0062] Let us consider the example of a series of 9 irons, one iron of which (for example a 6 iron or a 7 iron) serves as reference iron. Knowing the address position of the reference iron and knowing that the length difference between the successive irons of a series is knownin this example inchesit is possible to adjust the lie angle by calculation from formula [Math 3] in order to obtain a series of golf clubs having a constant address position, i.e. a substantially identical address position.