JPH07236716A - Metal golf club head and its production - Google Patents

Abstract

PURPOSE: To solve troubles associated with the manufacturing of a metal head of golf club by investment casting, by injecting, hardening and protruding a mixture of metal powder and a binder to form the first part, which is attached to the second part by heating the metal powder up to the enough temperature to be melted into a solid mass. CONSTITUTION: A club head 10 comprises two parts, that are, a front part 30 and a back part 32, which are to be divided by a broken line 34. Then, a mixture of pressed metal powder and plastic, namely a binder, are injected into a mold at a temperature of approximately 400 deg.F to be made separately, and when the mixture is hardened, the front part 30 and the back part 32 are protruded from the mold. Also, the mixture is treated to eliminated the binder by heating at a temperature of approximately 1000 deg.F. Lastly, the front part 30 and the back part 32 are heated by a temperature, which is enough to made the metal powder sintered and to eliminate the binder and to compress the metal powder to a solid part. Thus, the front part 30 and the second part 32 are connected and unified by welding, brazing or adhesion.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an improved two-piece metal golf club head molded by powder metal injection molding. The golf club head manufactured according to the present invention is strong and durable, has high reproducibility in terms of weight and dimensional accuracy, and can be manufactured efficiently.

[0002]

BACKGROUND OF THE INVENTION A limited number of golf club heads known as "irons" are still manufactured by traditional metal forging processes, and some club heads known as "woods" have persimmon trees or other It is still manufactured by machining the head from solid or laminated blocks of wood. However, most golf club heads (both irons and woods) are now made of metal by investment casting. This method consists of casting molten metal into a mold around a foam or wax pattern. When the cast metal solidifies, remove the product from the mold, then foam
Alternatively, the wax core is extracted to form a cavity in the product.
In the case of so-called "metal wood" club heads, the product obtained by the investment casting method is a hollow partially finished club head, which is completed by welding the bottom sole plate onto the head. It is also common in the prior art to add a foam back in the hollow portion of the head in order to add weight and to reduce the metallic noise at the time of collision with the golf ball, if necessary. Is.

With the development of metal club heads (particularly metal wood) formed by the investment casting method,
The drive distance on fairway shots has been increased, greatly improving the overall performance of the golf club. Since metal wood is hard and strong, it can transmit a large amount of power to the golf ball even with the same swing. Metal wood also reduces the distortion and bending problems found in conventional wood wood. However, while investment casting has greatly improved the performance of golf clubs,
Golf club heads made by the investment casting process have unique difficulties and limitations. For example, the inclusion of air or moisture in the investment foam,
Pinholes may form in the metal. Another problem is that in the investment casting process, the non-uniform flow of molten metal results in non-uniform wall thickness. Both of these problems affect the structural integrity of the golf club head and often cause wrinkles and breakage due to repeated impacts on the golf club head during use. Another problem specific to the investment casting process concerns the reproducibility or accuracy of the products produced by this process. As currently practiced, a separate foam or wax pattern for each club made by the investment casting process is made from the master die. This means that there is a slight dimensional variation for each pattern.
Such variations include moisture (humidity), form variables,
It is exacerbated by the melt chemistry and casting conditions. These manufacturing variations lead to dimensional deviations in the final product, which adversely affect important engineering properties of the club head.

To address these problems and limitations inherent in the investment casting process, founders have been one of the players in golf club heads made by the investment casting process.
I have to rely on a 00% visual inspection. When defects are found, if these defects are adjustable, secondary rework operations such as welding and polishing are required to correct the problem. Inspection and repair of each item by this method is time consuming and adds to the overall cost of the final product.

[0005]

SUMMARY OF THE INVENTION The present invention substantially eliminates the problems associated with golf club heads made by the investment casting process.

[0006]

According to the present invention, a powder metal injection molding process is used to provide strong, low structural defects,
A metal golf club head is manufactured that is highly uniform in terms of weight, wall thickness and dimensional characteristics and that can be manufactured more efficiently than golf club heads typically manufactured by the investment casting process. The club head is formed of two component pieces, at least one of which is manufactured by powder metal injection molding. For example, "Method of Injection Molding Powder Metal P
arts) '', US Patent No. 4,113,48 to Rivers
No. 0 and “Method for P
Nakamura U.S. Pat. No. 4,721,599, entitled "roducing Metal or Alloy Articles)," both of which are incorporated herein by reference, describes a powder metal injection molding process in its entirety. When applied in the context of the present invention, powder metal injection molding requires the injection of a mixture of fine metal powder (90-95% by weight) and a thermoplastic or thermosetting binder into a mold. The binder cures to form a solid "green" part (ie, a plastic or solid part that is held together by the binder) that is ejected from the injection mold. The green part is then subjected to heat and / or heat to remove most of the plastic or binder.
Alternatively, it is further processed using a solvent. Finally, green body parts are sintered at a relatively high temperature of, for example, 2,300 ~2,400 ⁰ F. This high temperature removes any residual plastic or binder and causes the finely divided metal powder particles to agglomerate into the final product without completely melting so that the molded part does not lose its shape.

The final product has a density of 90 to 100% of that of a fully wrought product.
It has a density of 98%. Although the parts produced during the injection molding process shrink significantly (about 20%) during sintering, the critical angle of the parts is maintained. Thus, all components that are molded and later processed have the same initial characteristics,
Almost no distortion or variation occurs. Also, because the powder metal injection molding method uses a master die that directly molds the parts, it can achieve very high accuracy and reproducibility with respect to the critical shape and weight of the club head. This differs from the investment casting process, which introduces non-uniformity in the resulting club head due to the inherent variability from mold to mold.
For example, it is preferable that the loft angle of the club head (the loft angle determines the trajectory of the golf ball at the time of hitting) does not exceed ± 1 °. However, the ordinary precision of the investment casting method is ± 2 due to the above processing variability.
Limited to loft angle tolerances of ~ 3 °. Thus, standard tolerances are limited by the capabilities inherent in investment casting processes. Similarly, when manufactured by the investment casting method, the lie angle of the golf club head (lie angle is
How to address the club head to the ball) also has a tolerance of ± 2-3 °. The combination of these two tolerances on the loft and lie angles of the club head in these extreme ranges results in an unusable club. According to the present invention, a club head can be manufactured with a lie angle tolerance of ± 1.5 ° or less.

Another important club head variable relates to the face angle of the club. Face angle refers to tilting the face of the club head toward (or away from) the ball, which affects the flight direction (lateral direction) of the golf ball. For example,
A "closed angle" or anti-slice club has been developed by moving the club face to the 11 o'clock position with respect to the club shaft. "Open angle" clubs counter the tendency of strong players to hook by displacing the head angle to the 1 o'clock position with respect to the club shaft. However, golf clubs made in accordance with the present invention can maintain a tolerance of ± 1 ° or better for all three above-mentioned angles of interest, namely loft angle, lie angle and face angle. This contributes to a significant improvement in golf club reliability. It is also important that the head weight of each club be accurate. For example,
Each iron club head ranges from a long iron, such as a 2 iron, to a short iron, such as a pitching wedge or a sand wedge, with about 5 to 5
Designed to gradually heavier by 7 grams. Similarly, metal woods are progressively heavier by about 5 grams for each largest difference, from long woods such as No. 1 wood to higher woods such as No. 5 wood. In order for the club to maintain the same swing weight and balance regardless of the length of the club, the head weight needs to be increased as the club is gradually shortened.

Currently used investment casting methods have a weight tolerance of ± 2-5 grams. Such tolerances are difficult to maintain constant due to the nature of the investment casting process and the required manual grinding and polishing. The large gate and runner traces commonly found in investment casting require multiple secondary operations to achieve a weight specification of ± 3 grams. In contrast, golf clubs made in accordance with the present invention can achieve weight tolerances of ± 2 grams or better without requiring extensive secondary work. Another important feature of the present invention is that the powder metal injection molding process substantially eliminates the presence of pinholes and other defects that affect the structural integrity of the golf club head commonly found in investment casting processes. It is possible to eliminate it. This reduces the number of unusable club heads manufactured and eliminates the need for close inspection. Also, because the powder metal injection molded material has a slightly lower density than the wrought material, the striking area of the club head can be made thicker, thus strengthening the striking surface while maintaining proper weight specifications. With such reinforcement, a more complete impact and club feeling can be obtained, which allows good control.

The club head of the present invention comprises two component pieces, namely, a front portion (one component piece) including a striking surface and a shaft connecting portion, and a back portion which constitutes the other component piece. It is formed. By molding the striking surface and the shaft connection as a single piece, the key angular relationships of the club head, namely the loft angle, the lie angle and the face angle, are incorporated into the single piece. This can improve the accuracy and reproducibility of the three important dimensions for each club head, as described above. The back of the club head opposite the striking surface is also preferably made by powder metal injection molding, but can also be made of plastic, glass fiber or other suitable material depending on the desired properties. The two club head portions are joined by interlocking or interlocking the portions together, or by welding, brazing or epoxy gluing, or a combination of these methods. A second feature of the invention is that the two club head portions can be easily aligned and joined. For example, the engaging edges of each portion may be formed with lips, ridges, grooves, etc. that are configured to interlock with corresponding features or features of the other portion. This can provide both easy alignment and high strength between the two parts when they are joined.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to make the understanding of the present invention easier, the present invention will be described with reference to the accompanying drawings. 1-6, a metal golf club head according to a preferred embodiment of the present invention is indicated generally by the reference numeral 10. The golf club head 10 is of the type commonly known as "wood" and includes a face 12 as best shown in FIGS.
It has a toe 14, a heel 16, and a shaft connecting portion 18. Further, the golf club head 10 is shown in FIG.
4 has a back 20 and a top surface 22 as best shown in FIG. 4 and a sole 24 as best shown in FIG. In accordance with the present invention, golf club head 10 is made of two or more component pieces, at least one component piece being formed by a powder metal injection molding process. In the preferred embodiment of the invention, the club head 10 comprises two parts, a front part 30 and a back part 32, both parts of which are shown in FIGS.
It is divided by a broken line 34 in FIG. In this configuration, the front portion 30 includes the club face 12 and the shaft coupling portion 18, which are united as a single piece. This is important for maintaining the good angular relationships of the club head 10, namely the loft angle, lie angle and face angle. Both parts 30, 32 are preferably manufactured by powder metal injection molding. This produces a highly precise piece, which is joined together by welding, brazing or gluing.

In FIGS. 7 to 11, the golf club head 1 is shown.
The selectable dividing lines that divide 0 into two parts according to the invention are indicated by dashed lines. As shown in these figures, the division of the club head into two component pieces can be virtually arbitrary. For example, the golf club head 10 has two portions (one portion including the toe 14 of the club and the other portion including the heel 16 and the shaft connecting portion 18) as indicated by the dashed line 36 in FIGS. 7-9 and 11. Including)
Can be configured with. The club head has two separate parts (one part including the striking surface and the shaft connection, as shown by various dashed lines 38, 40, 42 in FIG.
The other part may include the back of the club head). Further, the club head can also be divided diagonally along dashed line 39, as shown in FIG. 8 and 10 show another modification example that is divided along the broken line 37. In this variation, one club head portion includes the striking surface 12, the shaft connection 18 and the sole 24, and the other portion is essentially a quarter wedge piece, which is the top of the club head. Surface 2
Includes a portion of 2, a toe 14 and a back 20. However, it should be noted that any piece to be injection molded should not have a reentrant angle so that it can be ejected from the mold without breaking.

[0013] In powdered metal injection molding method, each club head portion, a mixture of pressurized powder metal and plastic i.e. binders, are made separately by injection into a mold at about 400 ⁰ F. Once the mixture hardens,
Pieces are processed to remove most of the plastic namely binder by heating to the protruded from the mold (are ejected) and about 1,000 ⁰ F. The club head portions 38, 40 are designed such that they have no reentry angle and project from these molds without damage. Finally, each piece is heated to a temperature (e.g., 2,300-2,400 < ⁰ > F) sufficient to sinter the metal powder. This temperature removes any residual plastic or binder and compacts the metal powder into solid pieces. During the sintering process, the part shrinks by about 20%. However, this shrinkage is uniform so that the resulting product maintains the desired angular relationship. Any of the standard alloys well known in the art such as, for example, 300 series stainless steel and precipitation hardened alloys can be used to make golf club heads by powder metal injection molding. The temperature of the heating process should be adjusted so that the specific metal powder sinters properly.

Alternatively, the spine 32 may be formed of plastic, glass fiber or other material and may or may not be injection molded. The back of the club does not experience the same stress as the front, so it can be made of other materials such as plastic. This may be desirable in reducing cost or gaining certain weight characteristics. Once more than one club head portion has been formed, these portions are joined together by welding, brazing or gluing to form the finished golf club head 10. In order to facilitate the joining of the club head parts, the engaging wall edge of each part is shown in FIG.
It is preferable to provide a mutual locking shape, that is, an engaging shape as shown in FIG. FIG. 12 shows two walls 50,
52 shows a schematic cross-sectional shape of the club head wall at the engagement edge of 52. One wall 50 has an outer lip 54 extending from the wall edge at an outer surface 58 of the wall and an opposite wall 52 an inner lip 56 extending from the wall edge at an inner surface 59 of the wall.
Have. FIG. 6 illustrates a club head 10 utilizing the engagement edge geometry of FIG. 12 with the outer lip 54 and inner lip 56 interlocking. This allows the two club head portions to fit together, which facilitates mutual alignment and coupling of the two portions.

FIG. 13 shows a "V" shaped engagement edge between two club head walls 60, 62 with the "V" shaped top opening toward the outer surface of the club head. . This shape is preferred if the club head portions are to be joined by welding. This is because the welding material melts together with the “V” -shaped exposed inclined surface 64 and simultaneously fills the “V” -shaped portion, so that a strong weld is obtained. Another structure is shown in FIG. 14 in which a central lip 74 extends from the center of the engaging edge of one club head wall 72, the central lip 74 extending to the other club head wall. It fits within a channel 76 formed in the engaging edge of section 70. This configuration also allows the club head portions to fit together accurately and tightly, improving alignment and bonding. Figure 15
~ 18 shows another engagement structure in which a rectangular peg 80 extends from the engagement edge of one club head wall 82, as shown in Figs. 17 and 18. .
The rectangular peg 80 fits within the rectangular cavity 84 formed by the wall 88 below the engaging edge of the opposite club head wall 86. This provides a strong and precise interlocking mechanism that joins the two club head portions together and can be used in combination with the other engaging edge structures described above.

After two (or more than one) club head portions are joined together to form a completed golf club head, a slight finishing operation can be performed to finish the seams between the club head portions. However, unlike club heads made by investment casting, extensive secondary work is not required. From the foregoing, it can be seen that a metal golf club head is provided that fully meets the objectives of the present invention. Although the present invention has been described in connection with the preferred embodiment, it is not limited to the embodiment but covers all modifications and equivalents within the scope of the claims.

[Brief description of drawings]

FIG. 1 is a front view of a golf club head according to the present invention.

FIG. 2 is an end view of the golf club head according to the present invention viewed from the toe direction.

FIG. 3 is an end view of the golf club head according to the present invention as viewed from the heel direction.

FIG. 4 is a plan view of a golf club head according to the present invention.

FIG. 5 is a bottom view of a golf club head according to the present invention.

6 is a cross-sectional view taken along the line AA of FIG.

FIG. 7 is a plan view of a golf club head according to the present invention with dashed lines indicating selectable positions at which the club head can be divided into portions.

FIG. 8 is an end view of the golf club head according to the present invention as viewed in the toe direction, with dashed lines indicating selectable positions at which the club head can be divided into portions.

FIG. 9 is a front view of a golf club head according to the present invention, with dashed lines indicating selectable positions at which the club head can be divided into portions.

FIG. 10 is an end view from the heel direction of a golf club head according to the present invention, with dashed lines indicating selectable positions at which the club head can be divided into portions.

FIG. 11 is a bottom view of a golf club head according to the present invention, with dashed lines indicating selectable positions at which the club head can be divided into portions.

FIG. 12 is a schematic cross-sectional view showing a structure of an engaging wall edge portion for integrally connecting portions of the golf club head according to the present invention.

FIG. 13 is a schematic sectional view showing a structure of an engaging wall edge portion for integrally connecting portions of the golf club head according to the present invention.

FIG. 14 is a schematic cross-sectional view showing a structure of an engaging wall edge portion for integrally connecting portions of the golf club head according to the present invention.

FIG. 15 is a plan view showing a part of the wall of the golf club head showing another structure of the engaging wall edge portion.

16 is a front view showing an edge portion of the engaging wall of FIG.

FIG. 17 is a plan view showing an engaging wall edge portion on a side opposite to the engaging wall edge portion shown in FIG.

FIG. 18 is a perspective view showing two facing engagement wall edges of the portion shown in FIGS. 15 to 17;

[Explanation of symbols]

 10 Metal Golf Club Head 12 Face 14 Toe 16 Heel 18 Shaft Connection 20 Back 22 Top 24 Sole 30 Front 32 Back 50 Wall 52 Wall 54 Outer Lip 56 Inner Lip 60 Wall 62 Wall 80 Rectangle Peg 84 Rectangle cavity

Claims (16)

[Claims] 1. A method of forming a two-piece golf club head by powder metal injection molding, comprising injecting a mixture of metal powder and a binder into a mold to form a first portion of the golf club head, Curing the mixture into the shape of the first portion in the mold, protruding the cured first portion from the mold, shaping the cured first portion into the shape of the first portion Heating the metal powder to a temperature sufficient to melt the metal powder into a substantially solid mass while maintaining the temperature of the first portion, and forming the golf club head into a shape of the first portion. Attaching to a second portion having a complementary shape. 2. The method of claim 1, wherein the second portion is formed by the manufacturing process of claim 1. 3. The method of claim 1, wherein the first portion and the second portion are attached by engaging mechanically interlocking or mating edges. 4. The method of claim 3, wherein the mechanically interlocking or intermeshing edges are secured together by welding, brazing or gluing. 5. The method of claim 1, wherein the first and second portions are integrally attached and secured by welding, brazing or gluing. 6. The mold has a shape forming a guide associated with the first portion, the guide of the first portion comprising:
The method of claim 1, wherein the attaching step aligns with the second portion. 7. The second portion is provided with a guide, and the guide of the second portion is the first portion in the attaching step.
7. Method according to claim 6, characterized in that it cooperates with a part guide. 8. The mold has a shape that forms a mechanical interlocking element associated with the first portion, the mechanical interlocking engaging the second portion during the mounting process. The method according to claim 1, characterized in that 9. The second portion is provided with a mechanical interlocking element, whereby the second mechanical interlocking element cooperates with the first mechanical interlocking element in the mounting step. 9. The method of claim 8, wherein the first portion is secured to the second portion. 10. A two-piece metal golf club head having a first portion formed by a powder metal injection molding method,
An edge having a cavity surrounded by an edge, the first portion having a second portion of the golf club, the second portion having a shape complementary to the shape of the edge of the first portion. A two-piece metal golf club head, characterized in that the first portion and the second portion are permanently joined together at the edge to form the golf club head. 11. The first portion includes a club face and a shaft connecting portion.
The golf club described in. 12. The golf club according to claim 10, wherein the second portion is formed by a powder metal injection molding method. 13. The first part has a first mechanical interlocking element and the second part has a second mechanical interlocking element whereby when the two parts are joined, the 11. The golf club of claim 10, wherein the elements cooperate to lock the first portion with the second portion. 14. The first portion and the second portion are welded,
The golf club head according to claim 10, wherein the golf club head is joined by brazing or adhesive bonding. 15. The method of claim 10, wherein the portion includes a guide that aligns the first and second portions when the first and second portions are integrally joined. The listed golf club. 16. The second portion comprises a guide, the guide of the second portion cooperating with the guide of the first portion when the first and second portions are integrally joined to each other. The golf club of claim 15, wherein the edges are aligned.