EP0611316A1

EP0611316A1 - Balanced golf club.

Info

Publication number: EP0611316A1
Application number: EP91918478A
Authority: EP
Inventors: Jean-Luc Veux; Benoit Vincent
Original assignee: TaylorMade Golf Co Inc
Current assignee: TaylorMade Golf Co Inc
Priority date: 1991-10-17
Filing date: 1991-10-17
Publication date: 1994-08-24
Anticipated expiration: 2011-10-17
Also published as: US5569097A; WO1993007935A1; US5467984A; EP0611316B1

Abstract

L'invention concerne un club de golf, de préférence un driver, comprenant un manche (1) à l'extrémité inférieure (10) duquel est montée une tête (2) et à l'extrémité supérieure (11) duquel est montée une poignée (3). Le club est léger et présente une masse inférieure à 340 grammes et le rapport (Longueur de Pendule Equivalent)/(Longueur du Club) est inférieur à 0,87, de préférence compris entre 0,87 et 0,85.The invention relates to a golf club, preferably a driver, comprising a handle (1) at the lower end (10) of which is mounted a head (2) and at the upper end (11) of which is mounted a handle (3). The club is light and has a mass of less than 340 grams and the ratio (Length of Pendulum Equivalent) / (Length of Club) is less than 0.87, preferably between 0.87 and 0.85.

Description

2 total mass of said club being less than 340 grams and is characterized in that the ratio of the length of the equivalent pendulum to the length of the club is less than 0.87, preferably between 0.85 and 0.87.

An additional feature of the invention is that the mass distribution on the club is such that the mass of the grip and the handle represents 30 to 40% of the total mass of the club.

Another characteristic of the invention is that the grip is light and its mass is less than or equal to 35 grams.

Other characteristics and advantages of the invention will emerge from the description which will follow with reference, without limitation, to the appended drawings and of which,

FIG. 1 represents a simplified view of the club according to the invention,

FIG. 2 represents a graph showing the positioning of an example of the club of the invention according to its characteristics compared to known traditional clubs,

FIG. 3 represents a simplified view of a golf club of the prior art,

FIG. 3a represents an enlarged detail of FIG. 3, in particular of the upper part of the club,

FIG. 3b represents the handle of the club of FIG. 3,

FIG. 4 represents a simplified view of a golf club according to the invention,

FIG. 4a represents an enlarged detail of FIG. 4,

FIG. 4b represents the handle of the club of FIG. 4,

FIG. 5 represents a variant of FIG. 4,

FIG. 5a represents a detail of FIG. 5,

FIG. 5b represents the handle of the club of FIG. 5,

FIG. 5c represents an improvement of the club of FIG. 5,

FIG. 6 represents a golf club of the invention according to another embodiment,

FIG. 7 represents a graph showing the variation of the LPE / Lc ratio as a function of the position of a counterweight on the handle of the club of FIG. 6.

The golf club of FIG. 1 comprises a handle (1) of length Is and of mass ms at the lower end (10) to which a head (2) of mass mt is secured. From the upper end (11) of the handle (1) is secured a handle (3) of mass mg and length Ig and extending over part of the length of the handle.

By convention, the length of the club (Le) is considered to be the length measured between a point O 'on the longitudinal axis (I, I') of the handle located 5 mm from the upper end or point O of the handle (3), and a point O "corresponding to 1

Balanced golf club

The present invention relates to an improved golf club more particularly of the "wood" type, as well as a set comprising such a club and having the same advantages as said club.

A golf club essentially comprises a handle commonly called a "shaft", at the lower end of which is secured a head, or striking member, and at the upper end, a handle also called a "grip".

The current trend is to make light golf clubs; on the one hand, to obtain a performance gain in terms of length and accuracy of the stroke, and on the other hand, to improve the playing comfort of the player; whether beginner or professional player.

A reduction in the head of the club directly influences the length of the stroke and therefore causes the opposite effect to that sought. Also the mass gain is obtained on the handle thanks to the use of composite materials technology. Clubs equipped with such sleeves make it possible to play strokes with a length increased by about 10% compared to that of clubs equipped with traditional sleeves.

Despite these advantages, most players dislike this kind of light clubs, due to the unpleasant sensations experienced when performing the strike movement, commonly called "swing" due to poor dynamic balance of the club. In particular, the Applicant has noticed that poor dynamic balancing directly influences the trajectory of the ball, leading to "slice", that is to say an outgoing trajectory to the right for a right-handed player (conversely outgoing to the left for a left-handed player), or "hook", that is to say a re-entrant trajectory to the left for the same player (reciprocally re-entering to the right for a left-handed player).

It is for these various reasons that professional circuit players continue to use certain traditional so-called "heavy" clubs whose sleeves are generally metallic or graphite, and which they find correctly balanced but whose performance is inferior to clubs whose handle light is made of carbon fibers for example.

The aim of the present invention is therefore to overcome the above-mentioned drawbacks, particularly by proposing a lean club, therefore efficient and whose dynamic balancing is identical or very close to that of the clubs preferred by most players.

The aim is also to offer a club set having the same advantages as the club thus created.

For this, the club of the invention consists of a handle at the upper end of which is secured a grip and at the lower end, a head; the between 280 and 340 grams and the LPE / Lc ratio is less than 0.87, preferably between 0.87 and 0.85.

An additional advantageous characteristic of the invention consists in distributing the mass over the club in such a way that the sum of the mass of the handle (mg) and the mass of the handle (ms) is between 30 and 40% of the mass total of the club (MT), which allows to keep a traditional head mass greater than at least 190 grams.

Point 27 in FIG. 2 illustrates the position on the graph of an example club according to the invention having a total mass equal to 322 grams and an LPE / Lc ratio equal to 0.866. As an example, the characteristics of such a club are presented in the following table: (for a static moment d2 of the scale lor thmi ue of the "swing-weight" measured at 14 inches or 355.6 mm from O )

Table 1

In general, the distribution of mass, inertias, centers of gravity, of the club and of the various elements constituting it can be determined by the following formulas:

LPE (at 0.1016 mm or 4 inches) = le / (MT (Gc - 0.1016)) + (Gc - 0.1016)

- MT being the total mass of the club is equal to mg + ms + mt expressed in kg

- G being the position of the center of gravity of the club from point O expressed in m

- the being the moment of inertia of the club expressed in kg. m ² and calculated by Huygens' theorem according to the formula: le = Is + Ig + It + (mg (G-Gg) ² ) + (ms (G-Gs-0.005) ² ) + mt (Lc-G) ² ) In this formula,

- G, Gs _r Gg are expressed in m

- mg, ms, mt are expressed in kg

- where Gg is the position of the center of gravity of the grip with respect to O; and Gs is the position of the center of gravity of the shaft with respect to O, the perpendicular projection on the axis (I, I ') of the center of gravity (20) of the head (2) of the club.

The club of the invention mainly concerns a "driver", that is to say the club having the greatest length (Le) among the clubs of the same set. But as will be explained later the invention extends in the same way to any club of said set which have the same advantages as the "driver" as they have been defined before.

According to the manufacturers, the "driver" is a club whose length (Le) can vary from 1041.4 mm (or 41 inches) for the shortest to 1143 mm (or 45 inches) approximately. Typically, the average length is around 1092.2 mm (43 inches).

For these club lengths, the applicant has established a graph illustrated in FIG. 2 on which measurements made on 26 drivers on the market appear to be compared with a driver of the invention. On this graph, the total mass (MT) expressed in grams of the driver is shown on the abscissa and the ratio of the equivalent pendulum length (LPE) to the length of the club is shown on the ordinate.

The LPE is given in mm and corresponds to a length equivalent to that of a simple pendulum whose oscillation period (T) is equal to that of the club if it is mounted pivoting around a point 01 corresponding to the point of rotation of the club in the hands of the player. In our example, it is located on the axis (I, I ') at 101.6 mm (4 inches) from point O.

The measurement of LPE can be carried out by various means such as those set out in US patent 4,674,324. As an example, we can cite the simplest method which consists in rotating the club around point 01 and measuring its period (T) of oscillation. The LPE is then obtained by the following formula:

LPE = (T ² g) / 4 π ²

(g being the gravitational constant expressed in mm / s ² ).

The characteristic of the invention is illustrated in FIG. 2. Among the 26 clubs on the market represented, the applicant has noticed that among the so-called "heavy" drivers numbered from 1 to 11 having a mass greater than approximately 340 grams, only clubs 1 to 4 with an LPE / Lc ratio of less than 0.87 have satisfactory dynamic balancing during the "swing". The clubs numbered from 5 to 11 have proved to be generally unsatisfactory, as have the so-called "light" clubs, that is to say those whose mass is less than 340 grams and numbered from 12 to 26.

On the other hand, clubs 12 to 26 have shown themselves to be more efficient in terms of speed of departure of the ball and therefore distance of the stroke played. This observation enabled the applicant to determine the characteristics of the driver of the invention whose total mass (MT) is less than 340 grams, preferably is variable along the handle and increases towards the end (11) of the handle so that the section is sufficient in the grip zone of the hands.

In a complementary characteristic of the invention illustrated in FIG. 4, 4a and 4b, the handle (1) comprises a first portion (13a) in the form of a truncated cone of length Is1 partially or completely covered by the handle (3) of thin, substantially constant thickness of length Ig. The handle includes a second remaining portion (13b) in the form of a trunk of cone of length Is2 also connecting to the first portion (13a). The generator G1 of the first portion (13a) has an average angle Θ1 relative to the axis (I, I ') and greater than the average angle Θ2 formed between the generator G2 of the second portion (13b) and the axis (I, I '). In the example described, the generators G1 and G2 are rectilinear but it is accepted that they can have a slight curvature in particular for the generator G1 of the first portion (13a).

The particular advantage of the mode of FIGS. 4 to 4b and which is added to those targeted by the invention and described above is mainly that the handle retains its ergonomic qualities in the hand tightening region due to its particular configuration.

Figures 5 to 5c show another example of possible configuration of the handle (1) leading to the same advantages. The handle (1) comprises a first upper frusto-conical portion (14a) of length Is1 completely or partially covered only by the handle (3) of length Ig. A second frustoconical portion (14b) not covered by the handle extends to the lower end (10) of the handle. The lower end (140a) of diameter d1 of the first portion (14a) is linked to the upper end of diameter d2 (140b) of the second portion (14b) via a third connection portion (14c ) of length Is3; the diameter d1 of the first portion being less than the diameter d2 of the second portion. The generator G3 of the handle (3) can advantageously be confused with the generator G'3 of the second portion (14b). _R In this way the handle is integrated flush with the handle (1). In addition in this case, the diameter d2 of the second portion being at any point greater than the diameter of a handle of the prior art like that of FIG. 3; the handle is more rigid in flexion and torsion than a conventional handle without being heavier.

Figure 5c shows an improvement made to the club of Figure 5 on which is added a connecting ring (16) covering the third connection portion (14c). This ring can advantageously be made of viscoeastic material having damping properties for example.

The sleeves (1) of the examples in FIGS. 4b and 5b are preferably produced in a composite structure based on carbon fibers and organic resin of the epoxy type for example. The manufacturing process for such sleeves is described in - Is being the moment of inertia of the handle with respect to Gs,

- Ig being the moment of inertia of the handle with respect to Gg,

- It being the moment of inertia of the head relative to the center of gravity (20) of the head.

The various constructions which will follow are given by way of example and are therefore in no way limiting.

In a preferred embodiment of the invention, the lightening of the club can be obtained by choosing a handle whose mass (mg) is less than 35 grams, preferably between 25 and 35 grams. For this, provision can be made for the handle generally made of elastomeric material to have a thin and substantially constant thickness of the order of 1 to 2.5 mm.

In this particular case, and by the formulas previously described, the characteristics of mass (ms), position of the center of gravity (Gs) and inertia (Is) of the handle can be optimized by calculation.

Thus, one can define a mass of the handle (ms) between 70 and 100 grams, preferably between 80 and 90 grams.

The results appearing in the following table are given as a specific example for a fixed mass of the handle of 35 grams and under the same conditions as in the example in Table 1.

Table 2

Advantageous characteristics of the invention and particularly of the preferred mode previously described, are illustrated in Figures 4, 4a, 4b, 5, 5a, 5b in comparison with the prior art illustrated in Figures 3, 3a, 3b.

Figure 3 shows a prior art golf club with a handle (1), a head (2) and a handle (3). The handle (1) has a regular frustoconical shape, the weakest section of which is located at its lower end (1), which is embedded in the head (2), and the strongest section is located at its upper end (11 ) from which extends the handle (3). By regular tapered shape, it is meant that the generator G of the truncated cone formed by the handle (1) is substantially rectilinear and forms an angle θ with the median longitudinal axis (I, I ') as shown in Figure 3b. For ergonomic reasons of play, the thickness (e) of the handle 8

The handle (1) of Figure 6 is made of composite material based on carbon fibers and resin.

The counterweight (4) can be arranged inside the handle (1) as shown in FIG. 6a. In this case, the counterweight can consist of an elastomer plug or other deformable material. It is also possible to envisage having a flyweight (4) in the form of a ring on the external surface of the handle (1) as in the case of FIG. 6b. It can also fill a housing (17) provided for this purpose so as to come flush with the external surface of the handle as illustrated in FIG. 6c. Finally, the counterweight (4) can be integrated into the internal structure of the handle as shown in FIG. 6d.

The use of a counterweight in the defined zone (15) can also be envisaged in the first embodiment of the invention, illustrated in FIGS. 4 to 5b if a readjustment of the dynamic balancing proves to be necessary after the manufacturing process of the club due to the dispersion of the different elements composing it. In this case, the addition of the mass is very low and of the order of only 1 to 10 g.

The present invention also extends to a golf club set comprising at least one club of the invention and in which each club which composes it has an LPE / Lc ratio of less than 0.87, preferably between 0.87 and 0.85.

In the normal declination of a set, the other clubs in the set have a total mass greater than that of the club of the invention, if this one is the driver, due to the mass of the head which believes as the decreases in the set. Also the head mass can vary from a minimum mass of 190 grams for a driver to a maximum mass of 350 grams for a putter.

An additional characteristic of the set of the invention is that each club can be balanced according to the traditional technique of static balancing known as "swing-werghting" without substantially modifying the LPE / Lc ratio for each club. The technique of "swing-weîghting" consists in balancing each club in the set by modifying the head mass so as to have the same static moment measured at 355.6 mm (either 14 inches or 355.6 mm O). For example, the formula for the static moment as a function of the club mass is: SW = MT (Gc- 0.3556) with - SW expressed in kg m

- MT expressed in kg with MT = mg + ms + mt

- Gc expressed in m

Of course, the invention is not limited to the embodiments described and shown by way of examples, but it also includes all the technical equivalents and their combinations. French patent applications No. 90 15387 and No. 90 15388 belonging to the applicant and which are added to the present description.

Of course, provision can be made for these handles by other more conventional methods well known to those skilled in the art.

FIG. 6 illustrates another embodiment of the invention. In this case, the handle (3) is conventional and has a mass (mg) of between 45 and 55 grams, preferably 50 grams. The handle (1) is very light and has a mass of less than 80 grams and includes a flyweight (4) located in a zone (15) located at a distance d from O 'equal to approximately 0.5 Le and of length equal to about 0.15 Le.

The flyweight has a mass between 1 and 40 grams. The area (15) defined in the context of the invention corresponds to the area for which dynamic balancing is carried out by adding the minimum mass by the counterweight. This characteristic is illustrated as an example in the graph in FIG. 7 which shows the variation of the LPE / Lc ratio as a function of the position of the counterweight (4) relative to the point O '.

On the abscissa is the length of the club Le expressed in mm.

On the ordinate is the LPE / Lc ratio.

Curve C1 illustrates an example of a non-counterweight handle whose balancing is not satisfactory.

Curves C2 and C3 illustrate two examples with a weight of 12 and 16 grams respectively.

The other parameters at C1, C2 and C3 are given in the following table as an example for a static moment d2 or "swing weight" of the club at 14 ouces):

10

16) Golf club according to claim 14 or 15, characterized in that the handle comprises a first portion (13a) in the form of a truncated cone of length Is1, partially covered at least by the handle (3) of length Ig and connecting to a second portion (13b), said first frusto-conical portion (13a) having a generator G1 whose average angle l'angle1 relative to the longitudinal axis (I, I ") is greater than the angle Θ2 means of the generator G2 of the second portion in the remaining frustoconical cone (13b) of length Is2 of the handle.

17) Golf club according to claim 14 or 15, characterized in that the handle comprises a first upper frustoconical portion (14a) of length Is1 partly covered at least by the handle (3) of length Ig, a second lower frustoconical portion (14b) not covered by the handle and extending to the lower end of the handle; the diameter d1 of the lower end (140a) of said first upper frustoconical portion (14a) being less than the diameter d2 of the upper end (140b) of said second lower frustoconical portion (14b) and said first and second portions (14a , 14b) frustoconical being connected by a third connection portion (14c) of length Is3.

18) Golf club set comprising several clubs of different length (Le), characterized in that it comprises at least one club according to claims 1 to 17 and in that each club of said set has an LPE / Lc ratio of less than 0.87 preferably between 0.87 and 0.85.

19) Golf club set according to claim 18, characterized in that each club has the same static moment measured at 355.6 mm (or 14 inches).

20) Golf club set according to claim 18 or 19, characterized in that the head mass can vary from a minimum value of 190 grams to a maximum value of 350 grams

Claims

9

Claims

1) Golf club, preferably a driver, comprising a handle (1) at the lower end (10) of which is mounted a head (2) and at the upper end (11) of which is mounted a handle (3) ; said club having a total mass of less than 340 grams, characterized in that the ratio:

Length of Equivalent Pendulum / Club length is less than 0.87, preferably between 0.87 and 0.85.

2) Golf club according to claim 1, characterized in that the sum of the mass of the handle (3) and the handle (1) is between 30 and 40% of the total mass of said club.

3) Golf club according to claim 1 or 2, characterized in that the handle (3) is light and has a mass less than 35 grams, preferably between 25 and 35 grams.

4) Golf club according to claim 3, characterized in that the handle (1) has a mass between 70 and 100 grams, preferably between 80 and 90 grams.

5) Golf club according to claim 1 or 2, characterized in that the handle (3) has a mass between 45 and 55 grams.

6) Golf club according to claim 5, characterized in that the handle (1) has a mass less than 80 grams.

7) Golf club according to claim 6, characterized in that the handle (1) comprises a flyweight (4) located in an area located at a distance d from the point O 'equal to about 0.5 Le and extends over a length equal to approximately 0.15 Le.

8) Golf club according to claim 7, characterized in that the weight (4) has a mass between 1 and 40 grams.

9) Golf club according to claim 6 or 7, characterized in that the flyweight consists of a plug disposed inside the handle.

10) Golf club according to claim 9, characterized in that the plug is made of elastomeric material or other deformable material.

11) Golf club according to claim 6 or 7, characterized in that the weight (4) is a ring disposed on the outer surface of the handle (1).

12) Golf club according to claim 11, characterized in that the ring (4) is arranged flush with the external surface of the handle, in a housing (16).

13) Golf club according to claim 6 or 7, characterized in that the flyweight (4) is integrated into the internal structure of the handle.

14) Golf club according to claim 2 or 3, characterized in that the handle (3) has a thickness (e) thin and substantially constant over its entire length (Ig).

15) Golf club according to claim 14, characterized in that the handle (3) has a thickness between 1 and 2.5 mm.