JP2006087928A - Golf club head provided with local groove and reinforcing member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a golf club head provided with a shell constituting an internal cavity and equipped with a face and a main body. <P>SOLUTION: A face is provided with a first section which is a reinforcing section of a first thickness and a second section which is the other section of a second thickness smaller than the first thickness. The reinforcing section is placed at the center part of the face. In the outer surface of the face composes at least one groove which is separated from the center part of the face. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a golf club head. In particular, the present invention relates to a golf club head having a local groove in the outer portion of the face and a reinforcing central region in the inner portion of the face.

  The complexity of golf club design is well known. The selection of specifications for each club component (ie, club head, shaft, hosel, grip and their subcomponents) directly affects the performance of the club. Therefore, the golf club can be adjusted to desired performance characteristics by changing the design specifications.

  Club head design has long been studied. Important considerations in club head design include loft, lie, face angle, horizontal bulge of the face (vertical bulge), vertical roll of the face, face progression, curvature of the sole, placement of the center of gravity, and There is weight of the whole head. While this basic set of criteria is generally at the heart of golf club engineering, several other considerations must also be considered. The internal design of the club head is finished to achieve specific performance by including hosel or shaft attachment means, peripheral weight distribution in the club head face or body, and filler in the hollow club head. The selection of materials for club head manufacturing must also be considered.

  The type of surface treatment on the outer surface of the face is an additional design consideration. The United States Golf Association (USGA), the organization that determines the rules of golf in the United States, recognizes that a golf club approved by the USGA if the surface roughness in the impact area of the face exceeds the roughness of cosmetic sandblasting or fine milling. Rules were established to prohibit use in competitions at all competitions. Ignoring this rule, it is widely known that many players roughen the club head face so that a relatively large backspin is applied during a shot.

  In addition, narrow grooves or grooves are traditionally provided on the face surface at regular intervals. These grooves are usually parallel and must meet the criteria specified by USGA for groove cross-sectional symmetry, groove edge roundness, spacing between adjacent grooves, and groove depth .

  Various theories have been developed that explain or reject the importance and effects of grooves. It is considered that the physical influence of the groove on the ball trajectory is partly due to, for example, an instantaneous deformation into the groove of the golf ball cover at the time of impact. This deformation is determined by the elastic modulus of the golf ball cover material. Grooves are generally believed to provide large scale or macro roughness to the club head face, thereby increasing backspin. Club face grooves also help players aim the club at the address. While the degree of influence of the face groove on the ball trajectory is discussed, it is highly appreciated that the groove is a significant consideration in club head design.

  The design of the golf club head must also be strong enough to withstand the impact forces that occur due to the contact between the head and the ball. The load that occurs during this short impact can give the golf ball an acceleration that is 20,000 times the gravitational acceleration, which is approximately four orders of magnitude greater than the gravitational acceleration. Thus, the club face and body should be designed to withstand permanent deformations such as cracks or sudden failures.

  In the case of prior art wood club heads, it is not uncommon for the face thickness to exceed mm (0.12 inches). This thickness has generally been required so that the club head face can withstand impact forces. The iron face must withstand substantial stress as disclosed in Kosmatka US Pat. No. 5,971,868. Thus, the iron face can be provided with a total back surface to enhance structural connectivity. Nevertheless, the design of hollow wood presents a distinctly different challenge than irons, especially for cavities constructed within the hollow wood. Wood is subject to different manufacturing stresses and performance requirements than irons, depending on whether it is made by shell casting, molding or other methods.

  Club head face thickness depends on various club head parameters, including overall club head weight, face stiffness, club head vibration characteristics, sound generated during ball-to-face impact, and club head center of gravity placement. Influence. In some club heads, it is desirable to minimize the thickness of the face. However, the thickness reduction must be compensated by adjusting for other design considerations. Such adjustment may include providing other structural features on the back surface of the club face or the inner surface of the club head shell. Another optional adjustment includes using a filler in the shell. Further, the overall structure of the club head can be adjusted by means such as using a face plate that fits into the shell of the club head by welding, brazing or other means. Alternatively, the faceplate insert may be formed integrally with the shell.

  Particularly in club head casting, it is difficult to repeatedly produce a desired shape with strict dimensional tolerances. However, the performance of golf club heads, particularly metal wood, is in part a function of the proper shape and size of the club face. One particularly annoying problem encountered during the casting of prior art club heads is that the club head face, which is usually cast first with a convex outer surface, collapses inward as it cools, causing the desired The shape cannot be maintained. Such a problem is exacerbated in a club head having a thin face.

  Accordingly, there is a need for a golf club head having a face that can be harmoniously manufactured with the desired club head shape and size and can withstand the impact stress associated with hitting a ball. In particular, a club club head with a sufficiently functioning thin face is required. Furthermore, there is a need for a club head that minimizes the backspin imparted to the golf ball.

  The present invention relates to a golf club head adapted to be mounted on a shaft. The head has a shell that defines an internal cavity. The shell has a face and a body. The face has an outer surface and an inner surface. A groove is formed on the outer surface of the face shifted from the center of the sweet spot or face.

  The local reinforcing portion is preferably provided on the inner surface of the face at the center of the sweet spot or face. As a result, the face includes two portions having different thicknesses. The local reinforcement portion has a first thickness that is greater than the second thickness of the remainder of the face. The second portion surrounding the first portion has a second thickness that is less than or equal to about 0.12 inches or about 0.148 inches. Thicker than the second thickness. The groove-free region on the outer part of the face has at least 25% of the face area including the center part of the face. Preferably, the groove does not extend across the outer surface of the face at the local reinforcement portion, and the groove ranges in area less than or equal to about 50% of the face area. The grooves are preferably at least 0.375 inches away from the center of the face in any direction.

  In one embodiment, the first thickness, ie, the thickness of the reinforcement portion, is greater than or equal to about 2.08 mm (0.08 inch), and the thickness is equal to about 2.032 mm (0.08 inch), and Less than or equal to about 0.148 inches (0.12 inches). The second thickness is less than about 3.02 mm (0.12 inch) or equal to about 3.048 mm (0.12 inch) and less than about 2.08 mm (0.08 inch) or about 2. More preferably, it is equal to 032 mm (0.08 inch). Most preferably, the second thickness is less than or equal to about 1.524 mm (0.06 inch). The first thickness can be uniform or can vary across the reinforcing portion. The first part and the second part are formed of the same material. Preferably, at least one groove extends substantially between the toe end and the heel end of the golf club.

  In another embodiment, the local reinforcement portion has an area of about 10% to about 90% of the face area. The local reinforcement portion is preferably less than about 15% of the face area. In yet another embodiment, the area of the local reinforcement portion is less than about 25% of the face area. The shell of the club head preferably includes a crown plate, a sole plate, a face, and a hosel, and the sole plate is formed integrally with the shell. Instead, the crown plate is formed integrally with the shell.

  The present invention is also directed to a golf club head adapted to be mounted on a shaft having a shell defining an internal cavity. The shell further has a face with first and second portions. The first portion is located at the center of the face and has a first thickness. The second portion has a second thickness that is less than about 0.12 inches or equal to about 0.12 inches. The first thickness is greater than the second thickness. Further, the face has an outer surface with a substantially smooth portion having an area greater than about 25% of the face area. The smooth portion is preferably located at the center of the face and has no groove. The smooth portion includes at least a portion of the first portion.

  The present invention also relates to a method of forming a golf club head comprising the step of forming a shell that forms an internal cavity with a face and a body. The step of forming the shell includes a first portion having a first thickness at the center of the shell and surrounding the first portion and less than about 0.148 inches or about 3.048 mm. Forming a second portion with a second thickness equal to (0.12 inches) on the face, wherein the first thickness is greater than the second thickness and forming the shell includes And forming a plurality of grooves on the face at a distance from the center of the face. Preferably, forming the shell further comprises casting the first portion simultaneously with the face. Instead, the step of forming the shell includes casting a first portion away from the face and then bonding the first portion to the face. In one embodiment, the face is embossed. In another embodiment, the face is engraved.

  Preferred features of the present invention will be described with reference to the accompanying drawings, wherein like numerals designate like elements throughout.

  With reference to FIGS. 1 and 2, a first embodiment of a golf club head 10 of the present invention is shown. The club head 10 has a shell 12 that includes a body 14, a face 16, a toe portion 18, a heel portion 20, and a top portion 24. The head 10 further includes a sole plate 26 (shown in phantom), a hosel 27, and a top portion 24. The sole plate 26 is fitted into a recess 29 formed in the main body 14. Shell 12 and sole plate 26 form an internal cavity 30. The face 16 preferably includes a plurality of grooves 32 on its outer surface 34. In the preferred embodiment, at least one groove 32 extends substantially between the toe portion 18 and the heel portion 20.

  In use, a golf club shaft (not shown) is attached to the hosel 27. The hosel may extend to the bottom of the club head, may terminate at an intermediate position between the top portion 24 and the sole plate 26, or the hosel may terminate at the top portion 24 of the head.

  The inner cavity 30 of the club head 10 may be empty, or alternatively filled with foam or other low specific gravity material. The shell is preferably cast as a whole, or at least the face 16 is formed of a higher strength alloy than the body 14. More preferably, the shell 12 is formed such that the body 14 and the face 16 are joined together, for example by welding, to form a homogeneous shell.

  In another embodiment, the shell 12 has a body 14, a face 16, a toe portion 18, a heel portion 20, a sole plate 26, and a hosel 27. The sole plate is formed integrally with the shell 12. In this embodiment, a separate crown plate (not shown) is attached to the shell 12 to form a hollow internal cavity. Alternatively, the crown plate may be integrally formed with the shell.

  In a preferred embodiment, the face 16 is cold forged or high strength SP-700 titanium alloy (Ti-4.5%, Al-3%, V-2%, Mo-2%, Fe) roll sheet. Embossed from stock. Instead, the face 16 is 10-2-3 (Ti-10%, V-2%, Fe-3%, Al) or 15-3-3-3 (Ti-15%, V-3%, Cr). -3%, Sn-3%, Al) and high strength forged titanium alloys. The body 14 is made by casting a 6-4 alloy (Ti-6% Al-4% V) with a sole plate 26 or a crown plate, preferably a titanium alloy different from the titanium alloy of the face 16.

  Referring to FIG. 2, a local reinforcement portion 36 is provided in the central region of the inner surface 40 of the face 16. In a preferred embodiment, the reinforcing portion 36 is formed of an additional material that is integrally cast as part of the face 16 or is formed as a separate piece that is attached to the face 16 by other means such as welding. . The reinforcement portion 36 is preferably made of the same material as the shell 12 to facilitate casting or to facilitate joining to the inner surface 40. As a variant, the reinforcing part 36 may be made of different materials. The reinforcing portion 36 preferably has a rectangular perimeter. In alternative embodiments, the reinforced portion 36 may be any other peripheral shape, such as an arcuate periphery or a reentrant shape. The reinforcing portion 36 may also be shaped according to another geometric pattern or profile, symmetric, or asymmetric.

  Referring to FIG. 3B, in a preferred embodiment, the side 42 of the reinforcement portion 36 is substantially perpendicular to the inner surface 40 of the face 16. In addition, the boundary edge formed on the lower line of the transition portion 44 between the face 16 and the reinforcing portion 36 has an irregular or inclined contour. For the side 42, other contours including a gradual or stepped slope from the top surface 46 of the reinforcement portion 36 to the lower line of the transition portion 44 may be used.

  It can be seen that the reinforced portion 36 has an inner surface region 40, ie, an area in the range of about 10% to about 90% of the face area. The inner and outer face areas are substantially the same. However, in the embodiment in which they change, any of them may be used as compared with the reinforcing region (area). In a preferred embodiment, the reinforcement area is approximately about 25% of the face area. Most preferably, the reinforcement area is about 15% of the face area.

  Referring to FIGS. 3A and 3B, the reinforcing portion 36 has a thickness t2 that is greater than the thickness t1 of the remainder of the face 16. Since the thicknesses t1 and t2 change to the minimum value in the groove 32, they are the maximum thicknesses of the respective regions. The thickness t2 of the reinforced portion 36 preferably ranges from about 2.08 mm (0.08 inch) to about 3.02 mm (0.12 inch). The thicknesses t1 and t2 may be uniform or may vary. The thickness t1 of the remainder of the face surrounding the reinforcing portion 36 is less than about 0.12 inches, more preferably less than about 0.08 inches, and preferably, Preferably, it is less than about 1.56 mm (0.06 inches).

  The reinforced portion 36 is provided at the center of the sweet spot or face 16 where the impact force is expected to be maximized, or is aligned with the central portion of the sweet spot or face 16, as defined below. This allows a thinner face 16 to be used compared to an unreinforced design. The reinforcement portion distributes stress so that the structural integrity of the face 16 is robust.

  The sweet spot is generally defined in mechanical terms as the intersection of the center of gravity and the longitudinal axis through the face 16. The center part of the face includes a sweet spot but points to a large area of the face. The central part is the part of the face that can be configured and surrounded on all four sides with the remainder of the face without the reinforcement part. Thus, the reinforcement portion can be arranged in alignment with the sweet spot or more generally in the center of the face.

  The horizontal projection line of the center of gravity preferably intersects the face 16 at the reinforcement portion, that is, the thick area of the club face. More preferably, the intersection of the face and the horizontal projection line of the center of gravity is located substantially at the center of the reinforcing portion 36.

  As shown in FIG. 3, the groove 32 in the outer surface 34 of the face 16 is provided in a sweet spot or a local region surrounding the central portion. Grooves, also called corrugations, are formed by carving, carving, cutting, embossing, or casting the shape into the head face. The face is preferably embossed and / or engraved. In the preferred embodiment, the groove 32 in the outer surface 34 is V-shaped (as best shown in FIGS. 3A and 3B). In another embodiment, these grooves are another shape, such as a square or U shape. The non-grooved portion of the club face is at least about 25% of the face area. The non-grooved portion preferably includes a central region of the face. Also, the groove is preferably offset from the reinforcing portion and does not extend across the reinforcing portion, covering an area that is less than or equal to about 50% of the face area. In a preferred embodiment, the at least one groove is at least 0.375 inches away from the center of the face in any direction. For example, a circle having a diameter of 19.05 mm (0.75 inch) without a groove may be formed at the center of the face.

  FIG. 4 illustrates another embodiment of a face 16 'for use with the club head 10 of the present invention (as shown in FIG. 1). The face 16 'has no grooves (as shown in FIG. 1). This “grooved” face 16 ′ preferably includes a very smooth outer surface 34 ′, as can be achieved with grinding and polishing techniques known in the art. Such a groove-free surface is effective in minimizing the degree of backspin imparted to the golf ball when it hits the club face 16 ', and therefore jumps out of the non-central portion of the face 16'. The tendency of the ball to hook or slice can be reduced. The absence of grooves also provides the golfer with the advantage of increasing the adjustment of the golf ball trajectory upon impact with an increase in roll. Thus, golfers can achieve longer distance shots with a club having a grooveless face as compared to a grooved or partially grooved face. The face 16 'includes the reinforcing portion 36 (as indicated by the phantom line) as described above.

  It should be appreciated that the absence of grooves 32 in the sweet spot or central region of face 16 (as shown in FIG. 1) provides the same advantages as in the case of the completely grooveless head face described above. For example, as shown in FIG. 3, providing a local groove 32 can, in some cases, follow a non-matching shot to provide the desired ball jump on the course. This is because the holding interaction between the surface of the ball and the groove is limited, or the deformation of the ball in the groove is limited.

Club head design is evaluated using computational techniques that can include the use of thin elemental analysis models. For a computer model club head, a 200 gram mass was maintained by adjusting the point mass value as the face thickness changed. The surface stress is determined assuming a 109 mph club head speed, and such stress may be used to evaluate face connectivity. Also important in club head design, therefore, in this model, the COR is determined using the following equation:
(Ν _ball-post −ν _club-post ) / ν _club-pre
here,
ν _ball-post represents the speed of the ball after impact,
ν _club-post represents the speed of the club after impact, and ν _club-pre represents the speed of the club before impact.

  COR generally depends on the shape and material properties of the colliding object. A perfect elastic collision has a COR of 1 representing no loss of energy, whereas a completely inelastic collision, ie a plastic collision, results in the maximum loss of energy, with the collision object not separating after the collision. With a COR of zero.

  Referring to FIG. 5, the club head design was examined using a two parameter design space consisting of COR and maximum stress or safety factor. By making iterative calculations in this space, one or more safetys still have a factor while approaching a target COR of 0.829 (for a relative speed of (48.768 m / s) 160 feet / second). I was able to. The target COR corresponds to the adjustment value established by the USGA. A club head that exhibits a safety factor of 1.0 or greater is the smallest design that does not dent during use. Club heads with data points in shaded area 60 have a safety factor of 1.0 or greater and are therefore acceptable.

  Line 62 has points indicating a plurality of conventional club heads having different face thicknesses t1. Line 62 shows that the COR decreases as the thickness increases from 20.32 mm (0.80 inch) (0.080 inch error?) To 2.667 mm (0.105 inch). The club head indicated by point A exhibits a safety factor of 1.0 and is therefore acceptable. Point A club head has a face thickness of 2.667 mm (0.105 inch). The club head at point A has a COR of about 0.72 for the club head considered.

Line 64 shows a club head of the present invention in which the club head at point B has a central reinforcing portion, where the thickness t2 of the central reinforcing portion is greater than the thickness t1 of the remaining face region as described above. The club head represented by point B exhibits a safety factor of 1.0 or greater, and therefore point B is shaded or within the tolerance region 60. The point B club head has a COR of 0.77 which is greater than the COR of the point A club head.

  The drivers (Comparative Club 1, Comparative Club 2, and Comparative Club 3) are one of 2.032 mm (0.08 inches), 2.286 mm (0.09 inches), and 2.54 mm (0.10 inches), respectively. Made with various face thicknesses. These clubs were tested using a robot manufactured by True Temper and the so-called Iron Byron.

  The COR values of comparative club 1, comparative club 2, and comparative club 3 were 104%, 101.3%, and 98.7% of the adjustment values, respectively. That is, as the thickness increased from club 1 to club 3, the COR decreased undesirably. Both Comparative Club 1 and Comparative Club 2 collapsed under the test conditions (ie, swing speed of 109 mps). Therefore, the comparative club 1 and the comparative club 2 are not acceptable.

  The club of the present invention has a reinforcing portion of 30.48 mm (1.2 inches) × 22.86 mm (0.9 inches) in the center. The thickness t2 of the reinforcing portion is 3.048 mm (0.12 inches). The balance thickness is 2.032 mm (0.08 inch). By computer modeling, the club of the present invention has reduced stress at the center of the face compared to a conventional club of uniform thickness. The thickness t1 may be further adjusted in consideration of off-center hits so that the COR can be reduced. Advantageously, the use of a reinforced portion as in the club of the present invention can provide an acceptable COR with a club head that exhibits excellent behavior under stress when compared to the comparative club 3, for example. Further, the face portion of such a club of the present invention has a thickness that is substantially less than that allowed for a club of acceptable uniform face thickness, such as the comparative club 3.

  While various embodiments of the present invention have been described above, it should be understood that various features of each embodiment can be used alone or in combination. Accordingly, the invention is not limited to the particularly preferred embodiments that have been described in the specification. Further, it should be understood that various changes and modifications within the spirit and scope of the present invention can be made by those having ordinary skill in the art to which the present invention belongs. Accordingly, all convenient modifications, which can be easily accomplished by those skilled in the art from the matters described in the present specification, within the spirit and scope of the present invention, are included as other embodiments of the present invention. Thus, the present invention is configured according to the claims.

1 shows a front perspective view of a golf club head of the present invention. 2 shows a bottom perspective view of the golf club head of FIG. FIG. 2 shows a front view of a first embodiment of the face of the golf club head of FIG. 1. FIG. 4 shows a cross-sectional view of the face along line 3A-3A in FIG. 3; FIG. 4 shows a cross-sectional view of the face along line 3B-3B in FIG. 3; The front view of 2nd Embodiment of the face of the golf club head of this invention is shown. The safety factor is shown as a function of COR for various faces of uniform and non-uniform thickness.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Golf club head 12 Shell 14 Main body 16 Face 18 Toe part 20 Heel part 24 Top part 26 Sole plate 27 Hosel 29 Recess 30 Internal cavity 32 Groove 34 Outer surface 36 Reinforcement part 40 Inner surface 42 Side part 44 of reinforcement part 36 Transition part

Claims (23)

A golf club head that can be attached to a shaft,
Comprising a shell comprising an internal cavity and comprising a face, the face comprising:
i) a first portion in the center of the face having a first thickness;
ii) surrounding the first portion and comprising a second portion having a second thickness less than about 0.12 inches or equal to about 0.12 inches; The first thickness is greater than the second thickness;
iii) a non-grooved region provided outside the face, the non-grooved region having at least 25% of the face area including the center of the face;
Golf club head.   The golf club of claim 1, wherein the second thickness is less than about 0.08 inches.   The golf club of claim 1, wherein the second thickness is less than about 0.06 inches.   The golf club of claim 1, wherein the first thickness is between about 0.08 inches and about 0.12 inches.   The golf club according to claim 1, wherein the first and second portions are formed of the same material.   The golf club of claim 1, wherein the first portion has an area of about 10% to about 90% of the area of the face.   The golf club of claim 6, wherein the area of the first portion is less than or equal to about 25% of the area of the face.   The golf club head of claim 7, wherein the area of the first portion is less than or equal to about 15% of the area of the face.   The golf club according to claim 1, wherein the first thickness is uniform.   The golf club according to claim 1, wherein the face has a plurality of grooves on the outer surface thereof spaced apart from a central portion of the face.   The golf club of claim 10, wherein the plurality of grooves are spaced at least 0.375 inches in any direction from a central portion of the face.   The golf club according to claim 10, wherein the plurality of grooves are offset from the first portion and do not extend across the first portion.   The golf club of claim 1, wherein the plurality of grooves bound an area that is less than or equal to about 50% of the area of the face.   The golf club according to claim 13, wherein the golf club has a toe end, a heel end, and at least one groove extending substantially between the toe end and the heel end.   The golf club head according to claim 1, wherein the shell includes a crown plate, a sole plate, a face, and a hosel.   The golf club according to claim 15, wherein the sole plate is formed integrally with the shell.   The golf club according to claim 15, wherein the crown plate is formed integrally with the shell. A golf club head that can be attached to a shaft,
Comprising a shell comprising an internal cavity and comprising a face, the face comprising:
i) a first portion in the center of the face having a first thickness;
ii) surrounding the first portion and comprising a second portion having a second thickness less than about 0.12 inches or equal to about 0.12 inches; The first thickness is greater than the second thickness;
iii) an outer surface with a substantially smooth portion having an area greater than about 25% of the area of the face, the smooth portion including at least a portion of the first portion;
Golf club head. A method for forming a golf club head comprising:
Forming a shell comprising an internal cavity and having a face and a body, and forming the shell comprises:
i) a first portion of the face that is provided in a central portion of the face and has a first thickness; and surrounds the first portion and is less than or equal to about 0.12 inches Forming the face with a second portion having a second thickness equal to 0.148 inches, the first thickness being greater than the second thickness;
ii) forming a groove in the face spaced from a central portion;
Method for forming a golf club head.   The method of forming a golf club head according to claim 19, wherein forming the shell includes casting the first portion simultaneously with the face.   The method of forming a golf club head according to claim 19, wherein the face is punched out.   The method of forming a golf club head according to claim 19, wherein the face is etched.   The golf club head formation of claim 19, wherein forming the shell includes casting the first portion separately from the face, and then bonding the first portion to the face. Method.

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