JPH07163689A - Shaft for golf club and its preparation - Google Patents

Abstract

PURPOSE: To provide a simple and economical method capable of effectively changing the mass characteristic of a shaft without modifying the general characteristics of the shaft. CONSTITUTION: In the manufacture of a golf club shaft of the type including a center conduit 15 limited by the inner surface 14 of a cylindrical wall 12 made of a composite material, with at least one balance weight M1, M2, or M3 contained in the center conduit 15, a fiber of a fixed thickness preimpregnated with a resin is wound around one mandrel. In a stage prior to this winding, at least one balance weight M1, M2, or M3 is placed between the outer face of the mandrel and the fixed thickness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a golf club shaft and a manufacturing method thereof. More specifically, the present invention relates to club shafts made of composite material and including at least one lumped inertial mass.

[0002]

2. Description of the Related Art When playing golf, a player has a head at the lower end of a shaft, while hitting the ball with a golf club consisting of a single handle having a grip portion at its upper end. To move. Golfers use several types of clubs to guide the ball into the hole, distinguished from each other by the shape of the head hitting the ball and the length of the shaft. During the motion preceding the impact of the club on the ball, the shaft undergoes a deflection that positions the impact. Similarly, vibrations that are extremely unpleasant to the player are also propagated, and after the impact of the ball, the player strongly feels unpleasantness that reduces his / her confidence in the club for the next hit.

Thanks to the development of new composite materials, properties such as torsional and bending stiffness can be more easily controlled and adjusted to desired values. Manufacturers use drape molding to produce shafts with the desired properties, so the number and amount of wrap layers, fiber (glass, carbon,
Kevlar) properties, fiber orientation (0/45 °)
Can be operated. Nevertheless, the main drawback still remains that, as a result of taking into account certain parameters, in particular stiffness, the other requirements, in particular the requirements regarding the shaft and thus the balancing of the assembled club, cannot be fulfilled. The term balancing is to be taken broadly and consists of adjusting the mass to the desired values and the center of gravity and inertia of the shaft to the desired values and positions. It is sometimes difficult to meet the requirements of stiffness and mass at the same time. Thus, in shafts made of composite material, one way of adjusting certain balancing parameters is possible by adding additional fibrous wrapping layers where desired. According to this work, the initially selected stiffness properties must be modified due to the high material loading due to the low density of the composite material.

[0004]

Accordingly, one of the objects of the present invention is to provide a simple and effective way to modify the mass characteristics of a shaft without modifying the general characteristics of the shaft, such as the overall stiffness. It is about proposing an economic solution.

Another object is to facilitate balancing of golf clubs whose shafts are made of composite material.

A complementary objective is to easily modify the mass of the shaft (and club) without changing the center of gravity and inertial properties. Yet another complementary purpose is to easily modify the mass and inertia of the shaft (and club) without changing the center of gravity characteristics.

[0007]

Thus, according to the present invention, a golfer of the type that includes a central conduit 15 defined by an inner surface 14 of a cylindrical wall 12 made of composite material and having at least one balance weight. The club shaft manufacturing method is such that a single mandrel 23 is wound with a fiber having a constant thickness pre-impregnated with a resin, and the outer surface of the mandrel 23 and this constant thickness are wound at a stage prior to the winding. Characterized in that it comprises at least one balance weight arranged in between.

According to another characteristic, the method is
Wrapping at least one first layer of fiber pre-impregnated with resin around one mandrel 23,
And arranging at least one balance weight on the first layer prior to the winding, the balance weight or weights being on the surface of the winding layer to form the inner surface of the shaft. It is installed in.

According to one complementary feature, in another preliminary step, one or more balance weights in the form of strips of dense material adhered onto one winding layer are provided. Be prepared. The strip of dense material advantageously contains a layer of adhesive or double-sided adhesive tape.

In a complementary step, the wrapping of the pre-impregnated fiber layer is carried out in advance and in advance of the wrapping by a piece covered with an elastic and airtight tubular bag 22 made of an elastomeric material. Performed around mandrel 23 of.
According to one preferred arrangement of the method, the mandrel 23 thus coated after the winding of the fiber layer
Is placed in a mold 28 having a cavity that defines the final shape of the shaft to be manufactured, and then a tubular bag in such a manner as to compress the composite structure toward the cavity surface in the mold. 22
The molding operation is carried out by applying at least one internal pressure exerted by introducing a fluid into the inside of the bag 22 between the mandrel 23 and the mandrel 23, whereupon the mold 28 causes the resin to polymerize. It is then heated to allow shaft fabrication and balance weight bonding.

The present invention also includes a central conduit 15 defined by an interior surface 14 of a cylindrical wall 12 made of composite material.
A golf club shaft of the type including at least one balance weight in the central conduit, wherein the balance weight or weights are in a molded sheet adhered onto the interior surface 14 of the shaft wall 12. A golf club shaft, characterized in that it is composed of a sheet of deformable material of high density.

According to a complementary embodiment, the material density of the balance weight or weights is determined by the wall 12 of the shaft.
The density of the single or plural balance weights is higher than the density of the composite material forming the composite material, and the material density of the balance weight is preferably 2 to 15 times the density of the composite material forming the wall of the shaft.

According to one embodiment, the balance weight constitutes an unclosed cylinder top wall around its circumference, while in another variant, the balance weight constitutes a cylinder roll. According to another arrangement, the balance weight consists of at least two identical balance weights symmetrically arranged on either side of the axis of the shaft, while in another variant the shaft is of the central conduit 15. It contains three identical balance weights evenly distributed in it.

[0014]

By arranging the balance weight near the center of gravity of the shaft, when the mass is increased, the position of the center of gravity and the inertia characteristic do not change as a whole. Further, by using a material having a large specific gravity for the balance weight, the change in the inner diameter of the central conduit of the shaft can be made small, and therefore the influence on the bending rigidity is small.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing the method of manufacturing a golf club shaft according to the present invention, first a plurality of embodiments of the club shaft will be described to better understand the method. As shown in FIG. 1, a golf club has a head 2 at a lower end 6 thereof, while having an upper end 5 thereof.
Is composed of a single shaft 1 supporting a grip 3. The lower end 6 of the shaft generally engages in a lateral extension of the head called the neck 4, while the grip 3 is composed of a sleeve made of a synthetic material such as synthetic rubber. The shaft 1 of the golf club is composed of a cylindrical tube having a slightly conical shape so that the upper end portion 5 is thicker than the lower end portion 6. It should be noted that the shaft 1 includes a lower portion 7 adapted to engage the neck 4 of the club head 2, while including an upper portion 8 engaged within the grip 3. The central part 9 is the lower middle zone 1
It extends downwards by 0 and extends upwards by the upper intermediate zone 11.

The tube forming the shaft is formed by a cylindrical wall 12 which includes an outer surface 13 and an inner surface 14 and forms a central conduit 15. According to one characteristic of the invention, the cylindrical wall 12 is made of composite material and the central conduit 15 comprises at least one inertial balance weight (M). The shaft 1 is thus made, for example, of fibers embedded in a polymerized organic resin. Carbon fiber pre-impregnated with epoxide resin is advantageous as the material used, but other fibers such as glass fiber, polyamide and other ceramics, boron and polyethylene can of course be used.

According to a preferred embodiment, the balance weight of the shaft is arranged at the level of the central part 9 of the shaft, and the balance weights (M1, M2, M3)
Is positioned near the center of gravity (G) that the shaft has without the balance weight. Thus, for example, the balance weight is at a distance (LM) from the upper end 5 of the shaft 1 equal to about half the overall length (L) of the shaft. According to one characteristic of the invention, the balance weights are arranged in a central conduit 15, which, according to the embodiment proposed in FIGS. Two peripheral balance weights (M1, M
2, M3) are included. Each of these balance weights consists of a plate of thickness (e), width (la) and length (lg) and is made of a high density material such as lead. Each balance weight is obtained, for example, by cutting out a small play from the lead plate which is sized to this balance weight and is integrated with the inner surface 14 of the shaft wall 12. The three balance weights (M1, M2, M3) are regularly arranged inside the shaft so that their respective centers of gravity (g) are arranged on axes (a1, a2, a3) forming an angle of 120 degrees with each other. It is convenient to distribute. This distribution thus ensures symmetry about the general axis (XX) of the shaft.

Balance weights (M1, M2, M3)
Is 0.1 mm to 1 mm thick (e), 5 mm to 25 m
The width (la) of m can have a length (lg) of 10 mm to 300 mm. The total mass of the three balance weights is 3 g to a shaft having a mass of 50 g to 90 g.
It is 50 g. As an example, for a shaft having a center of gravity (G) of 70 g, the total mass of the balance weights can be set to 10 g assuming that the shaft is arranged near the center of gravity (G).

4, 5, 6 and 7 are views similar to FIGS. 2 and 3 showing two alternative embodiments of the balance weight. According to the variant shown in FIGS. 4 and 5, the shaft 1 comprises only two identical balance weights (M1, M2) symmetrically arranged on both sides of the axis (XX),
On the other hand, according to the variants of FIGS. 6 and 7, there is only a single balance weight (Ma) having the partial shape of an unclosed tube on its periphery, which presents an opening (0).

The method of manufacturing the shaft is such that one or more balance weights are placed on the inner surface of the first layer of the fibers pre-impregnated with resin, which are integrated together to form another fiber layer of the same type. And around the mandrel, thus forming the shaft after crosslinking and shrinking the resin. The inner surface of the first layer is
The inner surface 14 of the shaft is formed.

The balance weight is an element having a high density or at least 2 to 15 times the average density of the material forming the shaft wall. However, preferably, the density of the material forming the balance weight is
It is eight times the average density of the wall to limit its outer dimensions. Lead is the preferred material, but any material is possible. Thus it is possible to utilize balance weights made of elastomers or plastics filled with dense metal particles.

In the following, the manufacturing method according to the invention will be described in a preferred embodiment shown in FIGS. The method includes the steps of manufacturing an elastic tubular bag 22 preferably having a length greater than or equal to the desired shaft length. The bag 22 is preferably made of an elastomer that allows latex dipping. This technique is well known to those skilled in the art, especially in the field of thin rubber gloves, bags and parts of complex shape, which are stretch-compatible and perfectly hermetic against gases and liquids. Among the elastomers available within the scope of the present invention, mention may be made of latex, neoprene or silicone elastomers. In the present invention, it is particularly preferable to use a latex bag.

As can be seen from FIG. 8, for this purpose a part or gauge plate 20 is used, which is immersed in, for example, a calcium nitrate coagulant bath and then in a latex bath 21.
After setting, the bag 22 is subjected to a firing step at 70 ° C-80 ° C for about 10 minutes. About 0.2-0.3m by this technology
It is possible to obtain a thin bag 22 such as m. After cooling, the bag is placed on a rigid forming mandrel 23 having a length equal to or greater than the length of the shaft to be obtained (Fig. 10). In parallel with the manufacturing process of this bag 22, different winding layers (N1, N2, N3, N4) of resin impregnated fibers are prepared and placed side by side as shown in FIG.

In another step, for example lead strips 2
4 ~ 3 balance weights (M
1, M2, M3), one side of this strip 24, for example the lower side, now contains one layer of adhesive or double-sided adhesive tape 25. These three balance weights made by cutting from the lead sheet are shown in Fig. 1.
As shown in FIG. 3, it is glued onto the first layer (N1) which constitutes the inner surface 14 of the shaft.

The next step, shown in FIG. 14, consists of covering the mandrel 23 with a layer of fibers impregnated with an organic resin. Materials used within the scope of the present invention are, for example, HM115 and THR115 type Hexcel-.
Carbon fiber pre-impregnated with an epoxy resin from Genin. Of course, this method can also be applied to the formation of shafts using glass fibers, polyaramids or other fibers such as ceramics, boron, polyethylene. The covering operation of the mandrel 23 is carried out by winding a sheet 26 with a spread of fiber layers oriented according to the desired properties.
Thus, a multi-layered frustoconical composite structure 27 of fiber layers is obtained. The formed mandrel 23 shown in FIG. 15 is, for example, a pre-impregnated fiber layer 7
It is covered with a composite structure 27 consisting of -16 layer stacks.

As shown in FIGS. 15-17, the mandrel 23 is then placed in a mold 28 having a cavity 29 which determines the external final shape of the shaft. The molding operation involves heating the mold and applying an internal pressure exerted by introducing gas into the elastic bag 22 in the form of compacting the composite structure 27 on the cavity 29 of the mold 28. Be implemented. The molding cycle depends on the nature and reactivity of the pre-impregnated material used. For example, for pre-impregnated epoxy resin, the mold is heated to 150 ° C and then cooled to ambient temperature. The heating time and cooling time are 7 minutes and 2 minutes, respectively. Pressurization work
It is carried out between 120 ° C and 140 ° C during the heating stage and remains stable until the end of the molding cycle. To this end, compressed air of about 10 to 12 bar is used. FIG. 17
Shows the placement of various components around the mandrel 23 after injection of a compressed fluid such as compressed air inside the bladder 22. After opening the mold 28, the mandrel 2
3 can be easily pulled out without any special tool by the space opened between the bag 22 and the mandrel 23 made by compaction and surrounded by the composite structure 27.

18-21 show in more detail the zones of the shaft in which the balance weights are located. 18 and 19 represent this zone before pressurizing and heating, and FIGS. 20 and 21 represent that after pressurizing. Before pressurization, the composite structure 27 has balance weights (M1, M2, M) around the mandrel 23 including the bag 22.
It can be seen that it is wrapped with 3). The composite structure 27 includes protrusions 270 locally at the balance weight level. Moreover, there is a space (E) between the surface of the mold cavity 29 and the composite structure. Upon pressurization, the bag 22 expands, at which time the composite structure 27 is deformed in the space (E) and attached to the wall 29 of the mold 28, thus the three balance weights are deformable balance weight materials. The flexibility of each occupies each place. The crosslinking of the resin of the first layer (N1)
Ensure adhesion of the balance weights on the inner surface 14 of the shafts 1,12.

22 to 24 show balance weights (M
b) shows a variant embodiment of the shaft of a club constructed by winding a band of high density material over one or more turns. 22 and 23 are views similar to FIGS. 2 and 3, and FIG. 24 is a view similar to FIG. Thus, the balance weight (Mb) is initially constituted, for example, by a strip cut from a lead sheet which is partially bonded onto the first layer (N1) constituting the inner layer of the shaft. Adhesion of this strip is such that this strip is first wrapped around the mandrel before the first layer (N1) is wrapped around in the next operation,
This belt-like material is adapted to project outward from the first layer (N1). Thus, it can be seen that the balance weight (s) is / are composed of a sheet of high density deformable material based on a sheet of shaped and glued onto the inner surface of the shaft wall.

The winding method refers to roll forming or filament winding of the winding layer. In addition, a single or a plurality of balance weights were arranged around the mandrel at a stage prior to winding. That is, it does not depart from the scope of the invention if it is placed on the surface of that layer as shown in FIG. 13 and not adhered to the first layer.

Naturally, the invention is not limited to the embodiments shown and described by way of example, but also comprises all equivalent techniques and combinations thereof.

[0031]

As described above, according to the golf club shaft and the method for manufacturing the same according to the present invention, the mass characteristics can be made simple and economical at the time of manufacturing without modifying general characteristics such as the rigidity of the shaft. Can be changed effectively by the method. It can also facilitate balancing of golf clubs whose shafts are made of composite material. Further, the mass of the shaft (and the club) can be changed without changing the center of gravity and the inertia characteristic, and the mass and the inertia of the shaft (and the club) can be easily changed without changing the center of gravity characteristic.

[Brief description of drawings]

FIG. 1 is an overall view of a front surface of a club provided with a shaft and a detailed vertical cross-sectional view near a center of gravity (G) showing a first embodiment of a shaft of a golf club according to the present invention.

FIG. 2 is a Y-Y sectional view showing the first embodiment of the present invention.

FIG. 3 is a partial cutaway perspective view showing a first embodiment of the present invention.

FIG. 4 shows a variant embodiment similar to that of FIG.

FIG. 5 is a diagram showing a modification similar to FIG.

FIG. 6 is a view showing another modification similar to FIG. 2;

FIG. 7 is a diagram showing another modification similar to FIG.

FIG. 8 is a diagram illustrating one step of the method of manufacturing a shaft according to the present invention.

FIG. 9 is a diagram illustrating one step of the method of manufacturing the shaft according to the present invention.

FIG. 11 is a diagram illustrating one step of the method of manufacturing the shaft according to the present invention.

FIG. 12 is a diagram illustrating one step of the method of manufacturing a shaft according to the present invention.

FIG. 13 is a diagram illustrating one step of the method for manufacturing the shaft according to the present invention.

FIG. 14 is a diagram illustrating one step of the method for manufacturing the shaft according to the present invention.

FIG. 15 is a diagram illustrating one step of the method of manufacturing the shaft according to the present invention.

FIG. 16 is a diagram illustrating one step of the method for manufacturing the shaft according to the present invention.

FIG. 17 is a diagram illustrating one step of the method of manufacturing the shaft according to the present invention.

FIG. 18 is a detailed view of a zone of the shaft including the balance weight in the manufacturing process, and is a vertical sectional view showing this zone before pressurization.

19 is a cross-sectional view taken along the line AA in FIG.

FIG. 20 is the same detailed view as FIG. 18, but here a longitudinal section A representing this zone after pressurization.

21 is a cross-sectional view taken along the line AA in FIG.

FIG. 22 is a view showing a modified embodiment similar to FIG. 2;

FIG. 23 shows a variant embodiment similar to that of FIG.

FIG. 24 is a diagram similar to FIG. 13 showing a modified embodiment.

[Explanation of symbols]

 1 Shaft 12 Cylindrical Wall 14 Inner Surface 15 Central Conduit 22 Cylindrical Bag 23 Mandrel 28 Mold 29 Cavity M Balance Weight

[Procedure amendment]

[Submission date] November 29, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is an overall view of a front surface of a club provided with a shaft and a detailed vertical cross-sectional view near a center of gravity (G) showing a first embodiment of a shaft of a golf club according to the present invention.

FIG. 2 is a Y-Y sectional view showing the first embodiment of the present invention.

FIG. 3 is a partial cutaway perspective view showing a first embodiment of the present invention.

FIG. 4 shows a variant embodiment similar to that of FIG.

FIG. 5 is a diagram showing a modification similar to FIG.

FIG. 6 is a view showing another modification similar to FIG. 2;

FIG. 7 is a diagram showing another modification similar to FIG.

FIG. 8 is a diagram illustrating one step of the method of manufacturing a shaft according to the present invention.

FIG. 9 is a diagram illustrating one step of the method of manufacturing the shaft according to the present invention.

FIG. 10 is a diagram illustrating one step of the method for manufacturing the shaft according to the present invention.

FIG. 11 is a diagram illustrating one step of the method of manufacturing the shaft according to the present invention.

FIG. 12 is a diagram illustrating one step of the method of manufacturing a shaft according to the present invention.

FIG. 13 is a diagram illustrating one step of the method for manufacturing the shaft according to the present invention.

FIG. 14 is a diagram illustrating one step of the method for manufacturing the shaft according to the present invention.

FIG. 15 is a diagram illustrating one step of the method of manufacturing the shaft according to the present invention.

FIG. 16 is a diagram illustrating one step of the method for manufacturing the shaft according to the present invention.

FIG. 17 is a diagram illustrating one step of the method of manufacturing the shaft according to the present invention.

FIG. 18 is a detailed view of a zone of the shaft including the balance weight in the manufacturing process, and is a vertical sectional view showing this zone before pressurization.

19 is a cross-sectional view taken along the line AA in FIG.

FIG. 20 is the same detailed view as FIG. 18, but here a longitudinal section A representing this zone after pressurization.

21 is a cross-sectional view taken along the line AA in FIG.

FIG. 22 is a view showing a modified embodiment similar to FIG. 2;

FIG. 23 shows a variant embodiment similar to that of FIG.

FIG. 24 is a diagram similar to FIG. 13 showing a modified embodiment.

[Explanation of Codes] 1 Shaft 12 Cylindrical wall 14 Inner surface 15 Central conduit 22 Cylindrical bag 23 Mandrel 28 Mold 29 Cavity M Balance weight

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sergi Sorviche Annecy 74000, France Bis Avenue de France 20

Claims (10)

[Claims] 1. A golf club of the type including a central conduit 15 defined by an interior surface 14 of a cylindrical wall 12 made of composite material, the central conduit 15 including at least one balance weight. In the manufacture of the shaft, the mandrel 23 is wound around a single mandrel 23 with a fixed thickness of fiber pre-soaked, and at a stage prior to the winding, the outer surface of the mandrel 23 and the fixed thickness are At least one balance weight (M, M
a, Mb, M1, M2, M3) are arranged. 2. At least one first layer (N) of fibers pre-impregnated with resin around the mandrel 23.
1) wrapping, and placing at least one balance weight (M, Ma, Mb, M1, M2, M3) on this first layer prior to this wrapping, this singular or The method for manufacturing a golf club shaft according to claim 1, wherein the plurality of balance weights are provided on a surface of a winding layer for forming an inner surface of the shaft. 3. In another preliminary step, one or more balance weights (M, M1, M1) in the form of strips of dense material which are adhered to said first layer (N1).
M2, M3) is produced, The manufacturing method of the shaft for Bruch clubs of Claim 2 characterized by the above-mentioned. 4. Golf according to claim 3, characterized in that the mandrel (23) is covered in advance and prior to winding with an elastic and airtight tubular bag (22) made of an elastomeric material. Method for manufacturing club shaft. 5. After winding of the fiber layer, the mandrel 23 thus coated is placed in a mold 28 having a cavity 29 defining the final shape of the shaft to be manufactured, which is then The tubular bag 22 and the mandrel 23 are shaped so as to compress the combined structure toward the hollow surface of the mold 28.
The molding operation is performed by applying at least one internal pressure exerted by introducing a fluid between the inside and the inside of the bag 22, and here the mold 28 is used for polymerizing the resin and thus for manufacturing the shaft. 5. The method for manufacturing a golf club shaft according to claim 4, wherein the balance weight is heated so that the balance weight can be bonded. 6. A central conduit 15 defined by an interior surface 14 of a cylindrical wall 12 made of composite material, the central conduit 15 including at least one balance weight (M,
Ma, Mb, M1, M2, M3) is included in a golf club shaft of a type including a single or a plurality of balance weights (M, Ma, Mb, M1, M2, M3).
Is made of a high density sheet of deformable material based on a molded sheet that is adhered onto the inner surface 14 of the wall 12 of the shaft 1. 7. The golf club shaft according to claim 6, wherein the density of the balance weight or balance weights exceeds the density of the composite material forming the shaft wall 12. 8. The golf club shaft according to claim 6, wherein the balance weight (M) is composed of at least two balance weights (M1, M2). 9. A balance weight (M, Ma, Mb, M1, M2, M3) or a plurality of balance weights are arranged at the level of substantially the center of gravity (G) of the shaft according to claim 6. The shaft for the described golf club. 10. The balance weight or weights are made of a lead sheet having a thickness of 0.1 to 3 millimeters, a width of 5 to 40 millimeters, and a length of 10 to 300 millimeters. The golf club shaft according to item 6.