DE1961735A1 - Golf clubs - Google Patents

Description

Golf clubs

The invention relates to golf clubs whose shaft is carbon contains asern.

Up until now, the shafts of golf clubs have been made from hickory, steel, fiberglass or aluminum. To achieve such Msteriaüisn using the necessary strength and rigidity zv, the minimum weight can be achieved with such materials is about 153 g (5 I / 2 ounces), 120 g (4 ounces 1/4), 12% (4 1/2 ounces) or about 110 g (3 7/8 ounces). The achievable minimum dimensions are:

009825/0112

BATH

Shaft material

Minimum weight d. Shafts-f. the woods shafts f .. "the iron

Shaft in upper lower upper lower

Diameter diameter

g (ounces) mm (inch) mm (inch) mm (inch) mm (inch)

Hickory- 153 (5 1/2) 19.0
(0.750) 11.4
(0.45) 1 9.0
(0.750) 12.7
(0.5) stole 120 (4th 1/4) 14.7
- (0.580) 6.9
(0.270; 14.7
(0.580) 8.9
(0.350) Glass fiber 128 (4th 1/2) 15.1
(0.600) 8.1
(0.320) 15.1
(0.600) 9.0
(0.355;) Alumin. 110 (3 7/8) 14.7
(0.580) 7.3
(0.290) 14.7
(0.580) 9.4
(0.370)

Such golf club shafts have a considerable inertia, so that a significant part of the total energy expended by the golfer when striking to accelerate the Shaft is used up and is therefore not used to accelerate the racket head and the ball.

In addition to its inertia, the shaft has some air resistance when swung onto a golf ball will. The inertia and drag of the shaft reduce the speed at which the club head moves can be hit on the ball. The part of this decrease caused by drag is not so as large as that caused by inertia, but must not be neglected. The speed of the club head When serving and dee ball can theoretically be increased by the fact that the inertia and air resistance of the Shank can be reduced. The former can be achieved by using a lighter material for the shaft

009825/0112

the latter by reducing the shaft diameter. However, the shaft of a golf club must have a certain minimum Have strength and stiffness if it is supposed to work properly. So far the difficulty could not be be solved satisfactorily, the golf club shaft more easily and to make it thinner without its other basic properties to be affected. It has now been found that the playing characteristics of golf clubs through use of shafts in which carbon fibers or threads are embedded can be significantly improved. at the shaft of the golf club according to the invention consists of with carbon fiber reinforced plastic.

The term "golf club" here includes woods and Irons and putters.

According to the invention, the necessary properties of a Golf club shaft achieved with a shaft weight of, for example, only about 57 to 100 g (2 to 3 1/2 ounces). The outside diameter is between about 13 to 15 mm (0.5 to 0.6 inches) at the top and between about and 8.5 mm (0.20 to 0.33 inches) at the bottom for woods .. or about 7.5 to 10 mm (0.30 to 0.39 inches) at lower end for iron, with such a shaft, the inertia and the air resistance are greatly reduced and it has been found that, for a given swing, a golfer can hit the ball up to about 7 1/2 to 9 meters (8 to 10 meters) yards) can hit farther than with conventional shafts without losing control or "feel". The increased hitting power of rackets with eggs according to the invention Shank is mainly achieved by increasing the weight of the club head. This is why possible because the weight of the shaft is reduced.

009825/01 12

Often, however, a number of woods and irons are to be put together to form a matching golf set. Traditionally, clubs with essentially the same "swing weight" are put together for this purpose. An improved method of assembling this is by choosing golf clubs with substantially the same moment of inertia about a given axis. The "swing weight" and moment of inertia of a golf club are normally measured with respect to an axis that is on or near the top,. ie the handle of the golf club lies. Both properties are proportional to the distance between this axis and the center of mass. (The moment of inertia increases proportionally to the square of the distance between the axis and the center of gravity.) As a result, when the weight is shifted from the shaft to the club head, that is, as the distance between the weight and the axis increases, both the "swing weight" and the moment of inertia of the Racket. If the "swing weight" or the moment of inertia is to be kept at a certain value, a reduction in the shaft weight with a weight "x" cannot be compensated for by an increase in the head weight by the weight "X". The increase in head weight must be slightly less than this value so that the weight or the center of gravity can be moved further away from the axis in question. In addition, in a golf club according to the invention, the weight of the club head can be approximately 10 % greater than that of a golf club with the same moment of inertia with a steel shaft. The golfer can quickly achieve the same swing with both types of clubs, the same head speed when hitting, but the heavier head strikes the ball further.

009825/01 1 2

A racket shaft according to the invention can be carbon fibers or a mixture of carbon fibers and glass fibers and / or a Metal foil or a metal mesh, preferably made of steel. The plastics can consist of a thermosetting Resin consist, for example of an epoxy, polyester, phenolic or other suitable synthetic resin. Once assembled, the resin can be cured to bond the components together and form a shaft of the appropriate strength or stiffness to form.

In one embodiment of the invention, the shaft can be made from one or more fiber sheets made of carbon fibers. These can be impregnated with a resin and cut to the required length and width and of the desired thickness. These fiber bundles or warp tracks can be rolled onto a mandrel that gives the desired internal shape of the shaft. The direction of the carbon fibers in the warp track or tracks are chosen so that when they are placed around the mandrel, the desired Combination of fibers in longitudinal, helical, spiral and / or radial alignment with respect to the longitudinal axis of the shaft or Doms results. This gives the shaft the necessary strength and flexural rigidity.

In another embodiment of the invention, one or more pre-impregnated fibers are used together with carbon fibers Warp tracks or fabrics made of glass are used, whereby the direction of the glass fibers in the glass fabric or the glass warp track is so is chosen that, when they are placed around the mandrel, the desired combination of carbon fibers and glass fibers helically, spirally, radially and / or in the longitudinal direction relative to the longitudinal axis of the shaft or mandrel results in the Shank the necessary strength and flexural rigidity give.

00982 5/0112

In a further embodiment of the invention, the Structure provided with a thin metal foil or a thin metal mesh, so that when the combination of carbon fibers or carbon fibers and / or glass fibers and / or metal is placed around the mandrel, the metal is the bending and torsional strength as well as the rigidity of the shaft increased.

In a further embodiment the carbon fibers are or ribbons spun on a mandrel. Also combinations of carbon fibers and glass fibers can be used in this Form in separate or common layers on the mandrel be upset. The fibers can be pre-impregnated with a resin or impregnated during application. During the spinning or winding of the threads, the turns or fibers should be applied around the mandrel at certain "angles and these are controlled during the entire winding process, so that the correct proportion of fibers is in Longitudinal, screw and spiral alignment with respect to the axis of the winding mandrel are applied and the shaft provided with a fiber spinning the desired strength and Has bending stiffness.

In a further embodiment of the invention, the carbon fibers or carbon fibers are used together with glass fibers in endless strands or another form of reinforcement impregnated in a resin bath and drawn through a die. This process is referred to as "drawing extrusion". Included In turn, the shapes of the reinforcement and the direction of the fibers are controlled to achieve the desired strength and strength To achieve flexural rigidity.

009825/01 12

To make tapered shafts using this process To be able to, the die preferably consists of a shape with the preferred external dimensions of the shaft. Further came; a mandrel can be used, which is the preferred one for the shaft Gives inner dimensions. This mandrel can be removed after the drawn-extruded shaft has hardened, whereby the shaft is then hollow. The thorn can be left ai-oh in the shaft preferably made of a lightweight material such as wood or foamed * plastic. In this In this case, the shaft is solid and the mandrel forms the inner core of the shaft.

In a further embodiment of the invention, the shaft can consist of a suitable plastic containing Kolilenstof fibers. A suitable material, for example, is a thermosetting molding compound such as that available from Courtäulds Ltd. is supplied under the designation '"Thermosetting Molding Compound Grade XI". This is an epoxy resin containing about 20 wt -% contains carbon fibers.. If desired, however, molding compositions can also be used which contain a significantly higher proportion of carbon fibers.

Shafts formed in this way contain randomly oriented carbon fibers. Although it is possible to produce sufficiently strong shafts in this way, the shafts are preferably produced by one of the methods described above, ie from a warp web, a tape or long threads or strands of carbon fibers. In this way, r of the fibers are very precisely set the direction, so that the desired strength results unc the gain in a specific direction is. For example, a first warp web made of carbon fibers can be applied in such a way that oil feathers lie essentially in the longitudinal direction of the shaft. Furthermore, additional fiber layers can be applied that those lying in these layers

009825/0112

BATH

Fibers, for example, at right angles or at 45 to the Fibers of the first web lie. This results in a particularly high strength and the reinforcement can in predetermined directions.

The carbon fibers used can only be made on their surface There are fibers pyrolyzed to graphite crystals, the interior of the fibers not being carbonized.

Using the exemplary embodiments described below and the single attached figure the invention is explained in more detail.

The figure shows a partial section of the inventive Shaft.

A shaft approximately 112 cm (44 inches) long for a golf club was made as follows:

A warp web 11 of carbon fibers was cut to a size of about 112 χ 10 cm (44 χ 4 inches) and about 0.25 mm thick with the carbon fibers oriented substantially parallel to the length of the web. This web has been impregnated, preferably at about 30% of its weight, with an epoxy or polyester resin and two other warp webs 12 and 13 laid out of carbon fibers. The webs 12 and 13 were cut to a size of about 112 χ 5 cm (44 χ 2 inches) and a thickness of about 0.06 mm (0.0025 inch) thick. The carbon fibers of these webs were aligned at about 45 to the carbon fibers of web 11, the carbon fibers of web 12 being transverse, preferably approximately at right angles to the threads of web 13. These sheets were preferably with about 50 wt -.% Epoxy or polyester resin impregnated. The tracks -12 and 13 were first arranged so that the edges of the two tracks butted against each other. These

009825/01 1 2

BATH ORIGINAL

Arrangement was placed on the web 11 as shown in the figure. The resulting stack of three webs was rolled onto a mandrel 10, the diameter of which is at the thicker end was about 13 mm (1/2 inch) and tapered towards the other end to a diameter of about 1.6 mm (1/16 inch). If desired, a sheet of impregnated glass fabric (possibly with a colored pigment) with a size of about 112 χ 0.025 to 0.13 mm (0.001 to 0.005 inches) and a width between about 76 mm (3 inches) at one end, which decreases to about 30mm (1.2 inches) towards the other end, rolled onto the outside of the carbon fiber sheet will.

The entire structure was cured under heat and pressure, for example in a press or in a pressure vessel. Alternatively, the assembly can be heat cured while pressure is applied from a contracting oellophane tape which is spirally wound around the outside of the uncured fibrous web after it is placed on the mandrel. After curing, the shaft was removed from the mandrel and the surface was ground to improve its appearance. The resulting shaft has an outside diameter of about 14.7 mm (330 inches) at the top and tapers to about 7.6 mm (0.3 inches) at the bottom. The shaft weighed only about 70 g (2 1/2 ounces) and had the strength and strength required for a golf club shaft. Bending stiffness.

To achieve different lengths of golf shafts and about various degrees of stiffness desired Different sizes, shapes and thicknesses of warp tracks can be used. Offset shaft patterns can, if desired, can be achieved with a suitably shaped mandrel and / or mold. The shaft does not need to go all the way to the lower end

009825/0112 ^BAD

• To be completely tubular. The inner end can also be massive which is a preferred form in some cases.

To produce a shaft of the proposed structure, other than those described or combinations these procedures are used.

The golf club shafts according to the invention are, among other things, tubular or partially tubular and consist partially or entirely of carbon fibers impregnated with a synthetic resin. Their weight can be between about 56 to 100 g (2 to 3 1/2 ounces), preferably about 70 g (2 1/2 ounces). Their diameter at the upper end can be, for example, between about 9 and 15.7 mm (0.350 to 0.620 inches), preferably about 12.7 to 15.2 mm (0.500 to 0.600 inches) and gradually or in steps towards the lower end about 3 to 10 mm (0.120 to 0.390 inch), preferably about 5 to 7.6 mm (0.20 to 0.30 inch) for wooden club shafts or about 7.6 "to 10.1 mm (0.30 to 0, 40 inch) for iron club shafts. Due to their special construction, they have the desired level of strength and flexural rigidity, so that they have a greatly reduced inertia and a greatly reduced air resistance and the golfer has the ball about 7 to 9 m (8 to 10 yards) can hit further than with golf clubs, the shaft of which has the conventional structure.

Suitable carbon fiber warp webs consist, for example, of those made by Oourtaulds Ltd. under the Type designation HM (high modulus) S.T. (surface treated for improved interlaminar shear strength) '.

009825/01 12

Claims (1)

PA TEH IAIS P RU Ό Η E Shank for golf clubs, characterized in that that it is made of a plastic reinforced with carbon fibers. 2. Shank according to claim 1, characterized in that that the carbon fibers are in the form of one or more warp tracks./ 3 shaft according to claim 2, characterized in that that a'Kettbahn made of carbon fibers is arranged so that the fibers are substantially in the longitudinal direction of the shaft. 4. Shank according to at least one of the preceding claims, characterized in that a second and third warp web of carbon fibers are arranged so that the fibers in the second and third webs in the are essentially at right angles to each other and at 45 ° to the longitudinal warp path. 5 shaft according to at least one of the preceding claims, characterized in that its weight is between about 57 and 100 grams (2 to 3 1/2 ounces). 6. Shank according to at least one of the preceding claims, characterized in that the shaft tapers and at one end has an outside diameter between about 9 to 15.7 mm (0.35 to 0.62 inches) and the other End has an outside diameter of between about 3 to 10 mm (0.120 to 0.39 inches). 7. Shank according to at least one of the preceding claims, characterized in that the plastic consists of a thermosetting resin. 009825/0112 B. shaft r.ich claim 7, characterized in that the resin consists of an epoxy, polyester or phenolic resin. 9. Shaft according to at least one of the preceding claims, characterized ζ e Ic e η η ζ eic Ii et η that he / or glass fibers and has a metal foil or metal mesh as additional reinforcement. 10. Shank according to at least one of the preceding claims, since, by geke-nnz eich net, that the carbon fibers consist of fibers that are pyrolized on their surface to graphite crystals. 11. A method for producing a golf club cliaft it according to at least one of claims 1 to 10, characterized in that "-kennz eich net that a sheet of carbon fibers with a thermosetting synthetic resin is impregnated that the impregnated web is placed around a mandrel, the outer dimensions of which the inner dimensions of the desired shaft and that the resin material, IaI is cured. 12. The method according to claim 11, characterized in that an additional sheet of impregnated glass ™ fibers are placed around the mandrel. 13. Golf club, characterized in that a head is attached to a shaft according to at least one of claims 1 to 10. 009825/01 12 BATH