JP2006043460A - Metal wood club with improved hitting face - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hitting face of a golf club head having improved flexural stiffness properties. <P>SOLUTION: In one embodiment, the hitting face is made from multiple materials. The main portion of the hitting face is a plate-like face made from a first material having a first density. A dense insert made from a second material having a second density that is greater than the first density is attached directly or indirectly to the plate-like face at or near the geometric center thereof. The dense insert increases the flexural stiffness of in a central zone of the hitting face so that a golf club head that has a larger zone of substantially uniform high initial ball speed. In another embodiment, the hitting face includes an insert that includes main plate and at least one wing extending therefrom. The insert is welded to the golf club head so that the main plate does not deflect separately from the remainder of the hitting face. The geometry of the face insert controls the flexural stiffness in the axial directions. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an improved golf club head. More specifically, the present invention relates to a golf club head having an improved striking face in which a zone with a high initial ball velocity is relatively large.

  The present invention relates to the golf club head disclosed in Patent Document 1 and Patent Document 2, and the contents of the disclosure should be referred to as appropriate.

  It is well known that golf club designs are complex. The use of club components (i.e., club head, shaft, hosel, grip, and those components) is directly linked to club performance. Therefore, by changing the design specifications, it can be finished to realize special performance characteristics.

  Club head design has long been studied. More important considerations in club head design include loft, lie, face angle, horizontal face bulge, vertical face roll, center of gravity, inertia, material selection, and total head weight. This basic set of criteria is generally the focus of golf club engineering, but several other design aspects must also be considered. The internal design of the club head, such as the hosel housing, the means for coupling with the shaft, the peripheral weight of the club head, and the filler in the hollow club head can be adapted to achieve specific features.

  The golf club head must also be strong enough to withstand repeated impacts that occur during a collision between the golf club and the golf ball. The load that occurs at this moment will give the golf ball a peak that exceeds 2000 pounds. For this reason, the club face and body must be designed to resist permanent deformation and critical damage due to material crushing and yielding. The face of the titanium hollow metal wood driver has a uniform face thickness greater than 2.5 mm, thereby ensuring structural integrity of the club head.

  Players typically seek a combination of metal wood drive and golf ball that achieves maximum distance and landing position accuracy. The ball flight distance after hitting is governed by the magnitude and direction of the translational speed of the ball and the rotation speed of the ball, that is, the spin. Environmental conditions including atmospheric pressure, humidity, temperature and wind speed further affect ball flight. However, the environmental effects are beyond the control of golf equipment manufacturers. The exact landing of a golf ball is also determined by many factors. Some of these factors are due to club head designs such as center of gravity and club head flexibility.

  The United States Golf Association (USGA), the governing body of golf regulations in the United States, has specifications for the performance of golf balls. These performance specifications define the size and weight of a compatible golf ball. One USGA rule limits the initial velocity of a golf ball after a given impact to 250 feet / second + -2% (or a maximum initial velocity of 255 feet / second). In order to increase the flight distance of the golf ball, the ball speed after impact and the coefficient of restitution of the impact between the ball and the club must be optimized while satisfying this rule.

  In general, if the influence of the environment is ignored, the flight distance of the golf ball depends on the total kinetic energy applied to the ball during the impact by the club head. In the event of a collision, kinetic energy is transmitted from the club and stored as elastic strain energy in the club head and as viscoelastic strain energy of the ball. After impact, the energy stored in the ball and club is converted back to kinetic energy in the form of translational and rotational speeds of the ball and club. Since the collision is not completely elastic, some of the energy is consumed for club head vibration and ball viscoelastic relaxation. Viscoelastic relaxation is a material property of parimer materials used in golf balls.

  Ball viscoelastic relaxation is a source of parasitic energy, which depends on the deformation rate. In order to minimize this effect, it is necessary to reduce the deformation rate. This can be realized by increasing the deformation at the time of a club face collision. Since the deformation of the metal will be purely elastic, the strain energy stored in the club face returns to the ball after the collision, resulting in an increased jumping speed of the ball after the collision.

Various methods can be employed to vary the allowable deformation of the club face. This includes uniform face thinning, thin face with rigid members as ribs, variable thickness, and others. These designs must have sufficient structural integrity to withstand repeated impacts without permanent club face deformation. In general, in a conventional club head, the ball initial velocity after the collision changes according to the collision position of the club face. Accordingly, it is desirable in the art to provide a large club head with a “sweet zone” that provides a large, substantially uniform initial ball velocity.
US Pat. No. 6,605,007 JP 2004-358225 A

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a club head having a large “sweet zone”.

  The present invention relates to a golf club adapted to be attached to a shaft. One embodiment of the present invention is a golf club having a striking face formed from a plurality of materials. The first material forms the central zone of the striking face. The central zone has a first flexural stiffness. The second material forms an intermediate zone concentric with the central zone. The intermediate zone has a second bending stiffness.

  Another embodiment of the present invention is a golf club head comprising a crown forming the upper surface of the golf club head, a sole forming the lower surface of the golf club head, and a striking face disposed between the crown and the sole. . The striking face has a face insert, and the periphery of the face insert is welded to the golf club head. The face insert has a main plate portion and at least one wing extending from the main plate portion.

  These and other aspects of the invention are set forth in the appended claims and will be described in detail below with reference to examples.

  According to the present invention, a club head having a large “sweet zone” is realized.

  US Pat. No. 6,605,007 discloses an improved golf club that also substantially increases the zone of high initial velocity or coefficient of restitution (COR), or “sweet zone”, which is substantially uniform.

COR or coefficient of restitution is a measure of collision efficiency. COR is the ratio of the speed at separation to the speed at approach. In this model, COR was therefore defined using the following equation:
(V _club-post -V _ball-post ) / (V _club-pre -V _ball-pre )
here,
V _club-post represents the speed of the club after the collision.
V _ball-post represents the speed of the ball after the collision.
V _club-post represents the speed of the club before the collision (zero value in USGA COR condition).
V _ball-pre represents the velocity of the ball before the collision.

  COR is generally dependent on the shape and material properties of the impacting object. In a completely elastic collision, the COR is 1 and the energy loss is zero. In an inelastic or completely plastic collision, the COR is zero and the impacted object does not separate after the collision, maximizing energy loss. This means that a large COR value results in a larger ball speed and distance.

As shown in FIGS. 1, 1 a, and 1 b, club accuracy and a large zone with uniform high initial velocity are realized by the striking face 2. The striking face 2 comprises a central zone 4, an intermediate zone 6 surrounding it and an optional surrounding zone 8. Preferably, the area of the central zone 4 is about 15% to about 60%, more preferably about 20% to about 50% of the total area of the striking face 2.

  The central zone 4 is relatively stiff and the intermediate zone 6 is relatively soft. As a result, when the ball collides, the intermediate zone 6 of the face 2 is deformed to realize a high ball speed. On the other hand, the central zone is not substantially deformed and the ball flies toward the target. When the ball collides, due to the deformation of the intermediate zone 6, the central zone 4 moves into the club head 10 and is pushed out. The intermediate zone 6 may be located adjacent to the central zone 4 and the optional surrounding zone 8 may be located adjacent to the intermediate zone 6. As a result, the head produces a coefficient of restitution exceeding 0.81.

Such a coefficient of restitution is achieved by imparting a first bending stiffness to the central zone 4 and a second bending stiffness to the intermediate zone 6. Flexural rigidity (FS) is defined as the average elastic modulus (E) of each part multiplied by the cube of the average thickness (t) of each part (FS = Et ³ ). How to calculate the average modulus and thickness is described in detail in the above-mentioned US Pat. No. 6,605,007, to which reference is made. The US patent also describes how to determine the FS when the thickness varies or when the material is non-uniform.

  Since the bending stiffness varies depending on the material and thickness, the following technique can be employed to form a substantial difference in the bending stiffness of the central zone 4 and the intermediate zone 6. (1) Different materials are used for each part. (2) Each part has a different thickness. Or (3) The material and thickness of each part are varied. For example, in the preferred embodiment, the thickness of the central zone is greater than the thickness of the intermediate zone and the material is common.

  In the club head 10, in order to achieve the above-described bending rigidity relationship, a material having a predetermined elastic modulus is selected and the thickness of each zone is changed. In another embodiment, in order to achieve the above-described bending stiffness relationship, the material of each part is changed to have a different elastic modulus, and the thickness is changed accordingly. Thus, the thickness of each zone may be the same or different depending on the elastic modulus of the material of each zone. Further, in order to obtain a desired bending rigidity, a structural rib, a reinforcing plate, and a thickness auxiliary material (parameter) may be used. The preferable ratio of the bending rigidity of the central zone 4 and the intermediate zone 6 is described in detail in the above-mentioned US Pat. No. 6,605,007, and the like is referred to.

Further, as discussed in the above-mentioned US Pat. No. 6,605,007, the striking face 2 may be manufactured using two or more different uniform materials. For example, the central zone 4 has a generally uniform thickness and is made of stainless steel having a Young's modulus of 30.0 × 10 ⁶ lbs / in ² . Adjacent intermediate zones 6 continuously taper from the flat periphery to the central zone 4. The thickness of the intermediate zone varies linearly. The intermediate zone 6 is made of a titanium alloy having a Young's modulus of 16.5 × 10 ⁶ lbs / in ² . Alternatively, as shown in FIG. 1c (corresponding to FIG. 10 of US Pat. No. 6,605,007), the central zone 4 has a stainless steel rib 4a with a Young's modulus of 30.0 × 10 ⁶ lbs / in ^2. You may have. The gap 4b is a titanium alloy having a Young's modulus of 16.5 × 10 ⁶ lbs / in ² . The intermediate zone 6 is made of a similar titanium alloy. The ratio of the bending stiffness of the central zone 4 and the intermediate zone 6 is calculated as shown in US Pat. No. 6,605,007.

  The optional peripheral zone 8 is preferably thicker than the intermediate zone 6 to increase bending stiffness. Alternatively, the optional peripheral zone 8 may be made of a material different from that of the intermediate zone 6 so that the bending rigidity of the peripheral zone 8 is greater than that of the intermediate zone 6. For example, the surrounding zone 8 is made of the same material as the central zone 4. The surrounding zone 8 may be made of a material completely different from the central zone 4 and the intermediate zone 6. In that case, the surrounding zone 8 is coupled to the intermediate zone by welding or the like.

  In FIG. 2 (FIG. 8 of US Pat. No. 6,605,007), the striking face 2 may comprise a face insert 42. Face insert 42 is welded to a cavity defined in the face. The striking face 2 may include a face insert 42 and a face support 30. In this embodiment, the striking face 2 is separated from the crown 14, the toe 18, the sole 22 and the heel 32 by a parting line 46. The central zone 4 is preferably arranged on the cavity-facing surface inside the face insert 42 and has an elliptical shape as shown. Details thereof are described in Japanese Patent Application Laid-Open No. 2004-358225. The central zone 4 is preferably aligned in the direction from low toe to high heel so that a high COR zone is established in the direction from high toe to low heel. This high COR zone preferably matches the golfer's typical striking pattern.

  As described in Japanese Patent Application Laid-Open No. 2004-358225 described above, “elliptical” or “elliptical” refers to a non-circular shape having a major axis (Major Axis) and a minor axis (Minor Axis). This includes, but is not limited to, any quadrilateral, geometric ellipse, rounded quadrilateral, and asymmetrical ellipse. A “major axis” refers to an axis that coincides with the longest line drawn in a non-circular shape without touching the surroundings more than twice (ie, start and end points). The “short axis” is perpendicular to the long axis near the center. Here, “concentric” means a shape that substantially surrounds another shape.

Intermediate zone 6 is shown as _{6 1} and _{6 2,} part, it can be placed on the face insert 42 form, in part, can be disposed on the face support 30. The transition zone 7 has various thicknesses and is arranged between the central zone 4 and the intermediate zone 6. Preferably, the thickness of the central zone 4 is less than the thickness of the intermediate zone 6 in the transition zone 7. Thereby, it is possible to suppress local stress distortion caused at the time of collision with the golf ball due to a sudden change in thickness. The face support 30 defines a hole 48 and the rim 49 forms the boundary. The face insert 42 can be joined to the face support by welding at or around the rim 49.

  Preferably, the face insert 42 is formed by milling or stamping and forming. In the manufacturing process, malleable metals available for the striking face, such as titanium, titanium alloys, carbon steel, stainless steel, beryllium copper, and other forgeable metals are heated and forged to the desired shape of the face cup. Examples of suitable metals include, but are not limited to, titanium 6-4 alloy, titanium 15-3-3-3 alloy, titanium 20-4-1 alloy, and DAT55, DAT55G (available from Daido Steel). included.

  A preferred forging process is die or billet forging, in which a premeasured rod of forgeable metal is heated and placed between the die and the hammer. The die has the desired shape of the face insert 42. The heated metal is processed into a desired shape by hammering. When the face insert 42 is manufactured by forging, the face thickness can be about 0.060 inches (about 1.5 mm) around its periphery.

  3-8, several alternative embodiments of the striking face insert 42 are shown. In the face inserts of these embodiments, the bending rigidity of the central zone 4 is due to the high density insert 52 formed of a material having a higher density than the material forming the other part of the face insert 42, and the rigidity of the intermediate zone 6. Greater than. A cross-section of the preferred embodiment of the present invention is as shown in FIG. 3 a, in which the face insert 42 includes a plate-like face 50 and an insert 52.

  The plate-like face 50 has an elliptical shape slightly bent, but any shape can be adopted. For example, it may be a polygonal shape, a circular shape, or an irregular shape.

  The size of the plate-like face 50 depends on the overall size of the golf club head 10. However, in the preferred embodiment, the length of the elliptical major axis of the plate-like face 50 is between 80 mm and 100 mm, and the length of the minor axis is between 35 mm and 60 mm. More preferably, the length of the ellipse major axis of the plate-like face 50 is 90 mm, and the length of the minor axis is 50 mm. The thickness 53 of the plate-like face 50 may be uniform or non-uniform. In one embodiment, the thickness 53 is in the range of 2-5 mm. Preferably, the thickness 53 is 2.7 mm and tapers gradually to a maximum thickness of 4.5 mm.

  The plate-like face 50 has a cavity 51 formed on the inner cavity facing surface 55 of the golf club head 10 as shown in an exploded view in FIG. Furthermore, the thickness of the plate-like face 50 is preferably increased around the cavity 51, thereby combining the effect of the thick central zone described above with the effect of the high density material of the high density insert 52. In this embodiment, the shape of the cavity 51 is circular, but the shape is preferably selected according to the cross-sectional shape of the high density insert 52. The size of the cavity 51 can be arbitrarily selected as long as the high-density insert 52 can be accommodated. In one embodiment, the cavity 51 has a width of about 14 mm and a depth of about 2 mm.

  As described above, the plate-like face 50 is preferably formed by forging, but a stamping or casting method may be used. The plate-like face 50 may be made of any of the materials discussed herein that are suitable for forming the striking face 2, for example, titanium, titanium alloy, carbon steel, stainless steel, beryllium copper can be used. . The most preferred metal is the titanium 6-4 alloy described above.

  The high-density insert 52 is a truncated cone as shown in the figure, and its cross-sectional area is smaller than that of the plate-like face 50. The high density insert 52 may be any shape suitable for manufacturing, for example, a cylinder, a circle, an ellipse, or a quadrilateral disk. The high-density insert 52 is made of a material having a higher density than the material of the plate-like face 50, and is preferably made of tungsten or stainless steel, but any material having a higher density than the plate-like face 50 is suitable for the present invention. This material can be used and includes copper, nickel and bronze. The high-density insert 52 is milled or stamped from sheet metal, and manufactured by forging, die cutting, or an arbitrary position technique.

  The size of the high-density insert 52 is preferably smaller than that of the plate-like face 50. In the preferred embodiment, the high density insert 52 has a diameter of about 10 mm at the maximum width portion and a height of about 7 mm. Since the height of the high-density insert 52 is greater than the depth of the cavity 51, the high-density insert 52 protrudes from the internal cavity facing surface 55 of the plate-like face 50. The size of the high density insert 52 can be varied to increase or decrease the effective size of the central zone 4.

  The high-density insert 52 may be fixed directly or indirectly to the plate-like face 50. In the preferred embodiment, the high density insert 52 is housed in a cap 56 formed of the same material from which the plate-like face 50 was manufactured. The cap 56 can be easily welded to the plate-like face 50 because of the same material. The high density insert 52 may be attached to the inner surface of the cap 56, may be glued at least on the inner surface, or simply disposed within the cap 56. As shown, the cap 56 is a truncated cone and has an internal cavity shape that allows the high density insert 52 to fit tightly within the cap 56. The cap 56 may be manufactured by a known method, and for example, casting, stamping, or forging may be employed.

  The high-density insert 52 is indirectly fixed to the plate-like face 50. Since the high-density insert 52 is accommodated in the cap 56 connected to the plate-like face 50 by the weld bead 58, the high-density insert 52 is repeated with the golf ball. When colliding, the high density insert 52 does not jump out of that position. Alternatively, at least a portion of the high density insert 52 and cap 56 assembly may be secured within the cavity 51 using an adhesive. Adhesion is, for example, a melt adhesive, an epoxy adhesive, a polyurethane adhesive, a sealant, a thermosetting adhesive, a UV curable adhesive, an acrylic adhesive and a cyanoacrylic adhesive.

  In FIG. 4, an alternative embodiment of a face insert 42 having a high density insert 52 is shown. In this embodiment, the high density insert 52 is a circular disc and is directly bonded to the internal cavity facing surface 55 of the plate-like face 50. Alternatively, the high density insert 52 may be welded to the surface of the plate-like face 50.

  In FIG. 5, another alternative embodiment of a face insert 42 having a high density insert 52 is shown. In this embodiment, the plate-like face 50 has a cavity 51, and a high density insert 52 in the form of a circular disc is inserted therein. The high-density insert 52 may be attached to the cavity 51 by, for example, an adhesive, or may not be attached. The flange portion 54 extends so as to cover the high-density insert 52, and the high-density insert 52 is held in the cavity 51 when it repeatedly collides with the golf ball, that is, does not jump out of the cavity 51. The flange portion 54 may be a metal piece welded to the plate-like face 50. Alternatively, the flange portion 54 may be formed when the plate-like face 50 is manufactured. The face insert 42 is preferably processed by milling or stamping. In the manufacturing stage, the cavity 51 is formed in the thick central zone of the plate-like face 50. The cavity 51 is formed slightly higher than the high density insert 52. The high density insert 52 is disposed within the cavity 51 and is preferably adhered to the inner surface of the cavity 51. The surface of the plate-like face 50 is strongly hit and deformed so that a part of the cavity 51 protrudes into the shape of the high-density insert 52, thereby forming the flange portion 54.

  In FIG. 6, another alternative embodiment of a multi-material face insert 42 is shown. This embodiment includes a plate-like face 50 similar to the plate-like face of the embodiment described above. However, in this embodiment, the plate-like face includes a thin-film wall cup-like protrusion 60, and this protrusion 60 extends outward from the inner cavity facing surface 55 of the plate-like face 50. The cup-shaped protrusion 60 has a trapezoidal shape in the illustrated example, but any shape can be adopted. For example, a hollow cylinder, a three-dimensional polygon, or an irregular shape.

  The high-density insert 52 is similar to that described above, and has a shape and size that fits tightly in the cup-shaped protrusion 60. The high-density insert 52 may be attached to the inside of the cup-shaped protrusion 60 using, for example, an adhesive. However, the high-density insert 52 is held in the cup-shaped protrusion 60 by the flange portion 54. This is the same as the above-described flange portion. However, in this embodiment, when the flange portion 54 is formed by stamping, the cup-shaped protrusion 60 is raised to constitute the surplus portion.

  In FIG. 7, a cross section of another alternative embodiment of the face insert 42 of the present invention is shown. The plate-like face 50 of this embodiment is similar to the plate-like face described in the above-described embodiments. However, in this embodiment, the cap 56 is a hollow cylinder. The outer diameter of the cylinder is smaller than the diameter of the cavity 51. The high density insert 52 is a circular plug that fits tightly into the cap 56. This plug is preferably attached to the cap 56.

  The cap 56 includes an edge 64 that is shaped and dimensioned to fit exactly into the cavity 51. There is a slight gap between the outer diameter of the cap 56 and the edge of the cavity 51. A weld bead 58 is formed around the edge of the cavity 51 and the edge of the edge 64 to couple the cap 56 to the plate face 50. Such a configuration of the cap 56 increases the adhesion area of the weld bead 58 and increases the bonding strength. Since the bond strength is increased, the high-density insert 52 is less likely to jump into the internal cavity of the golf club head 10 due to breakage, and as a result, the life of the striking face 2 is extended.

  8 and 8a, a face insert 42 of yet another alternative embodiment of the present invention is shown. In this embodiment, the face insert 42 includes a plate-like face 50 and a high density insert 52. However, the gap 61 is formed in the vicinity of the center of the plate-like face 50 so as to penetrate the thickness completely. The high-density insert 52 is preferably configured such that a portion thereof fits into the gap 61 while the edge 63 is placed on or attached to the lip-shaped shelf 66 of the gap 61. The flange portion 54 is similar to the above-described flange portion, and the high-density insert 52 is firmly attached. Due to such a configuration, the high-density insert 52 is visible from the outer facing surface 65 of the plate-like face 50. Although the outer surface of the high-density insert 52 is shown to be substantially flush with the outer facing surface 65 of the plate-like face 50, it need not be so, and there should be a gap at the edge of the gap 61. May be. However, the high density insert 52 is still visible from the outside.

[Example]

  The club W of the present invention is generally a hollow metal wood club head manufactured according to the embodiment shown in FIG. The club W has a face insert made of a titanium alloy plate, which is welded with a tungsten insert at or near the geometric center of the plate to the inner cavity facing surface. With this configuration, the thickness of the club W changes so that the central zone of the face insert is thicker than its periphery. The measurement result of the club W COR was 0.812.

  The standard King Cobra ™ SZ440 club head is also a hollow metal wood club head. The SZ440 club head has a variable thickness striking face. Similar to the club W, the thickness of the SZ440 club head is thicker near the geometric center of the striking face and thinner toward the periphery. However, the thickness change of the striking face of the SZ440 club head is realized integrally with the production of the striking face. That is, the striking face includes a single plate material, and a portion of the material is scraped near the periphery of the plate. The COR of the SZ440 club head is 0.814, which is almost equal to the COR of the club W.

  Both clubs were tested in a pendulum test. This test is a standard test of club face flexibility or trampoline effect under USGA rules and international rules. In this test, a small steel pendulum is used to impact the golf club head multiple times at a specific spot. The characteristic time between the club head and pendulum is recorded in microseconds (μs), and the flexibility of the golf club head at that point is determined. According to USGA rules, nine points on the golf club head are tested as such. Generally, the longer the characteristic time, the greater the flexibility of the golf club head.

この発明の他の側面によれば、打撃フェース２上の中間ゾーン６および周囲ゾーン８を、溶接線をクラブヘッドの打撃フェースからクラウンおよびソールへ移動させることにより、薄い構成で製造できる。打撃フェース２の性能を改善する代替的な手法は、フェースインサート４２の溶接線およびジョイントをクラブヘッド１０の他の面へ移動することである。周知のように、溶接線またはジョイントは不連続な領域であり、同一の材料の１つの部品を結合したとしても、両部品の構造的な特性はその連結部周辺で変化する。クラブヘッドのクラウンまたはソールへの溶接線を除去すると、打撃フェースの厚さを正確に制御でき、打撃フェース全体を薄くできる。ジョイントは打撃フェースの特性を変化させるためにも用いることができる。この発明のこの側面によれば、フェースインサートは１または複数の側壁を具備し、この側壁がクラウンの一部やソールの一部を形成する。 As shown in Table 1, the pendulum characteristic time for club W is longer than the characteristic time for SZ440 at all test positions. Therefore, even if the COR of both club heads is substantially the same, the flexibility of the club W is greater than that of the SZ440 club.

According to another aspect of the invention, the intermediate zone 6 and the surrounding zone 8 on the striking face 2 can be manufactured in a thin configuration by moving the weld line from the striking face of the club head to the crown and sole. An alternative approach to improving the performance of the striking face 2 is to move the weld line and joint of the face insert 42 to the other surface of the club head 10. As is well known, a weld line or joint is a discontinuous region, and even if one part of the same material is joined, the structural properties of both parts change around the joint. By removing the weld line to the crown or sole of the club head, the thickness of the striking face can be accurately controlled and the entire striking face can be made thin. The joint can also be used to change the characteristics of the striking face. In accordance with this aspect of the invention, the face insert comprises one or more side walls that form part of the crown and part of the sole.

In FIG. 9 (FIG. 9 of JP 2004-358225 A), the face insert 42 includes a central zone 4, a transition zone 7, an intermediate zone 6 portion, a crown 14 portion and a sole portion 156. The club head 10 thus defines a cavity 158 that is sized and shaped to receive the face insert 42. The face insert 42 is preferably welded to the club head 10. The face insert 42 constitutes the striking face 2 together with the face support 30. Similar to the embodiment of FIG. 2, the intermediate zone 6 is designated 6 ₁ , 6 ₂ and partially contacts the face insert 42 and partially contacts the face support 30.

  In FIG. 10, another embodiment of the present invention is shown. In this embodiment, the central zone 4 of the striking face 2 is formed by the face insert 42. The face insert 42 is preferably welded to the club head 10 along the weld line 20. The face insert 42 includes a polygonal or elliptical main plate portion 34 and side walls or wings (upper wings) 70 that extend in the direction of the crown 14 to form part of the crown 14. With this configuration, the upper portion (upper weld line) 71 of the weld line 20 is moved to the crown 14. By removing the distortion caused by the weld line 20 from the striking face 2, it is possible to suppress the occurrence of damage along the upper weld line 71 when receiving repeated impacts from the golf ball.

  The face insert 42 is preferably made of the same material as the rest of the club head 10. For example, titanium, titanium alloy, steel, or any other material suitable for use in a club head. The face insert 42 is preferably the same thickness as the other parts of the club head 10, but the face insert 42 may be thickened or thinned in order to change the bending rigidity.

  The shape and dimensions of the face insert 42 are various. As described above, the face insert 42 is a modified oval U-cup or L-cup, but may have other shapes. For example, a rectangle, an ellipse, or a circle. The face insert 42 preferably protects the entire surface of the striking face. However, the face insert 42 may form a smaller part of the striking face. Further, the wing 70 may extend to the sole 22 to form a part of the sole. This is shown in FIG. It is only necessary to change the shape of the face insert 42. In this case, the affected weld line is the lower weld line 73.

  The material properties of the face insert 42 are affected by the technique selected to manufacture the face insert 42. For example, after the sheet metal is cold-rolled or cold-worked to align the metal crystal grains, the face insert 42 is preferably manufactured from the sheet metal by stamping. Stamping such metal makes the striking face stronger than other methods. Further, the face insert 42 is arranged in the striking face 2 so that the flow pattern of the grains is aligned in the direction from the sole to the crown. Alternatively, the grain flow pattern of the face insert 42 may be aligned in the heel-to-toe direction, that is, the diagonal direction. Other known techniques can be used to manufacture the face insert 42. For example, forging or casting.

  12a and 12b show another embodiment of the club head 10 that is similar to the embodiment of FIG. In this embodiment, the face insert 42 has a main plate portion 34, an upper side wall or upper wing 70 that extends in the direction of the crown 14 to form a part of the crown 14, and a part of the sole 22 that extends in the direction of the sole 22. And a lower side wall or lower wing 72. Constructed in this way, the upper weld line 71 and the lower weld line 73 are moved to the crown 14 and the sole 22, respectively, to reduce the possibility of damage to the face insert 42. Other features of the face insert 42 have already been described with reference to FIG.

  FIGS. 13a and 13b show yet another embodiment of a club head 10 similar to the embodiment of FIG. In this embodiment, the face insert 42 includes a main plate portion 34, an upper side wall or upper wing 70 that extends in the direction of the crown 14 to form a part of the crown 14, a part of the sole 22 that extends in the direction of the sole 22, and a heel. It has a lower side wall or lower wing 72 that forms an extension part and a toe extension part. The upper wing 70 and the lower wing 72 are the same as those described with reference to FIGS. 10, 12a and 12b. The heel extension 74 and the toe extension 75 are extensions of the main plate portion of the face insert 42 that extends along the horizontal axis 76 at a position approximately in the center of the vertical axis 78. Changing the geometry of the face insert in this manner can increase the flex performance of the face insert 42 along the horizontal axis 76, while the vertical axis 78 has a smaller and different flex characteristic.

  The shape and dimensions of the face insert 42 are generally preferably as described in the embodiments of FIGS. 10, 12a and 12b. That is, it is a polygonal or elliptical main plate portion, which forms many portions of the hitting face 2. The upper wing 70 and the lower wing 72 are preferably elliptical or polygonal as a whole, but other shapes contemplated by the present invention may be employed. Similarly, the heel extension part 74 and the toe extension part 75 are preferably in a shape similar to an ellipse, but other shapes planned in the present invention, for example, a shape corresponding to a circle, may be employed. Thus, the preferred geometric shape of the face insert 42 includes an oblong center having a major axis along the horizontal axis 76 of the striking face 2 and a generally rectangular extension extending along the vertical axis 78 of the striking face 2. (Plural). Further, one of the heel extension part 74 and the toe extension part 75 may be omitted. One or both of the upper wing 70 and the lower wing 72 may be omitted. Furthermore, as shown in any of the embodiments shown in FIGS. 3 to 8, the face insert 42 may be integrated with the high-density insert to improve performance. The face insert 42 may include a central zone 4 and an intermediate zone 6, where the bending stiffness of the central zone 4 is greater than the bending stiffness of the intermediate zone 6. This is as described in US Pat. No. 6,605,007 and JP-A-2004-358225. Further, the central zone 4 may include a high density insert 52 as described above.

  The striking face 2 is preferably manufactured by milling or stamping and milling. The body of the club head 10 is preferably manufactured by casting. The internal cavity of the club head 10 may be a cavity or may be filled with foam or other low specific gravity material. The volume of the internal cavity is preferably greater than 250 cubic centimeters. More preferably it is larger than 275 cubic centimeters, most preferably larger than 350 cubic centimeters. Preferably, the club head weight of the present invention is greater than 150 grams and less than 220 grams. Details of the club head components, manufacturing method and COR value additional test results of the present invention are as discussed in Japanese Patent Application Laid-Open No. 2004-358225.

  Another parameter that affects the stiffness of the structure is inertance. In general, inertance is a frequency response. More specifically, inertance affects the structure, in this example the club face stiffness, at various vibration frequencies. The unit of inertance is the unit of acceleration relative to the unit of force. The preferred first resonant frequency of the inventive club face described herein is arranged to maximize inertance. A test technique and apparatus for determining inertance is as described in US Pat. No. 6,605,007.

Referring to FIG. 14, a graph of inertance versus frequency for a conventional club head is shown. A conventional golf head is an 8 ° loft Callaway Great Big Bertha War Bird. The point I ₁ of the frequency of 3330 Hz is the first main resonance frequency, and is the point where the first main maximum inertance of the inertance function I occurs. One maximum value does not represent the main resonant natural frequency of the face, but is also represented as point I ₂ at a frequency of 2572 Hz in FIG. This second maximum value I ₂ is characterized by an inertance transition with a magnitude of less than 10 decibels. This second maximum may be due to vibrations of the crown, sole or skirt that do not move perpendicular to the face of the club face. The second maximum value is not correlated with the COR and the ball measure because the vibration response is numerically small and does not match the ball response. The COR of the conventional club head tested was measured according to USGA, Rule4-1e Appendix II, 2nd edition, February 8, 1999 and found to be 0.785. A preferred first main resonance frequency of vibration is defined by the following relationship:
1 / (2 × contact period) <I ₁ <3 / (2 × contact period)
The contact period is the time interval during which the ball is in contact with the club face. In a typical driver collision, the contact period is 500 microseconds (500 × 10 ⁻⁶ seconds). Thus, the preferred main resonant frequency of club head vibration is between about 1000 and 3000 Hz. The closer the contact time is to the lower limit, the greater the COR, resulting in a higher rebound ball speed. More preferably, the first main resonance frequency is less than 2900 Hz. FIG. 15 shows the inertance function of the club head of the present invention, the details of which are described in US Pat. No. 6,605,007. The first main resonance frequency was 2632 Hz, and the COR of the club of the present invention was measured as 0.824. The COR of the invention of US Pat. No. 6,605,007 is larger than the conventional club of FIG. 14 and achieves a higher ball rebound speed.

  The overall bending stiffness of the club head and the distribution of bending stiffness across the face of the club head affects the resonance frequency of the club head. In addition, the swing speed determines whether the club and / or golf ball vibrates at the resonant frequency upon impact. Therefore, by changing the structural design and characteristics of the club head, the club designer changed the resonance frequency of the club head to harmonize with the resonance frequency of each golf ball and was launched at a predetermined swing speed. It is possible to increase the flight distance of the ball. Also, if the club is set for an individual golfer, the club can be designed to resonate when a particular golf ball is launched at the golfer's average swing speed. For example, if the club and ball resonate at a similar frequency, that is, if the ball collides and resonates from the club tail, the vibration of the club and ball acts to push the ball faster out of the club face. Preferably, the resonance frequency of the club is 0-20% greater than the resonance frequency of the ball. More preferably, the resonant frequency of the club is 0-10% higher than the resonant frequency of the ball.

  Although various aspects of the present invention have been described so far, it will be apparent that the various features of each embodiment can be used alone or in combination. Thus, it should be apparent that the present invention should not be limited to the specific preferred embodiments described herein. Further, it is obvious that those who have knowledge in the field to which the present invention can make modifications and changes within the spirit and scope of the present invention. For example, the thickness may change stepwise or continuously in the face or individual zones. In other variations, surrounding zones that are thicker or thinner than adjacent intermediate zones may be used. Furthermore, the shapes of the central, intermediate and surrounding zones are not limited to the shapes described above. Accordingly, all modifications that can be readily made by a person skilled in the art in accordance with the disclosure contained herein without departing from the spirit and scope of the present invention are described in the other embodiments of the present invention. Included as The scope of the invention is defined by the claims.

FIG. 6 is a front view of a hitting face of a golf club head of US Pat. No. 6,605,007. It is sectional drawing which follows the 1A-1A line | wire of the hitting face of the golf club head of FIG. It is sectional drawing which follows the 1B-1B line | wire of the hitting face of the golf club head of FIG. 2 is an alternative example of the golf club head of FIG. 1. FIG. 2 is an exploded front view of the golf club head of FIG. 1. It is a front view of the striking face of one embodiment of the present invention. FIG. 4 is a cross-sectional view of a hitting face taken along line 3A-3A in FIG. 3. FIG. 4 is an exploded sectional view of the striking face of FIG. 3. It is sectional drawing of the striking face of the other Example of this invention. It is sectional drawing of the striking face of other Example of this invention. It is sectional drawing of the striking face of other Example of this invention. It is sectional drawing of the striking face of other Example of this invention. It is sectional drawing of the striking face of other Example of this invention. FIG. 9 is an exploded sectional view of the striking face of FIG. 8. It is a disassembled front view of the other Example of the club head of this invention. It is a perspective view of further another embodiment of the club head of the present invention. It is a perspective view of further another embodiment of the club head of the present invention. It is an upper perspective view of further another embodiment of the club head of the present invention. FIG. 12b is a bottom perspective view of the club head of FIG. 12b. It is an upper perspective view of further another embodiment of the club head of the present invention. FIG. 13b is a lower perspective view of the club head of FIG. 13b. 4 is a graph of inertance versus frequency for a conventional club head. 4 is a graph of inertance versus frequency for a club head of the present invention.

Explanation of symbols

2 Strike face 4a Rib 4b Gap 4 Central zone 6 Intermediate zone 7 Transition zone 8 Peripheral zone 10 Golf club head 14 Crown 18 Toe 20 Weld line 22 Sole 30 Face support 32 Heel 34 Main plate part 42 Strike face insert 46 Type dividing line 48 Hole 49 Rim 50 Plate-like face 51 Cavity 52 High-density insert 54 Flange portion 55 Internal cavity facing surface 56 Cap 58 Weld bead 60 Cup-like projection 61 Air gap 63 Edge 64 Edge 65 External facing surface 66 Shelf 70 Wing (upper wing)
71 Upper weld line 72 Lower wing 73 Lower weld line 74 Heel extension 75 Toe extension 76 Horizontal axis 78 Vertical axis 156 Sole part 158 Cavity

Claims (19)

Having a striking face,
The hitting face is
A central zone partially formed of a first material and having a first bending stiffness;
An intermediate zone that is concentrically arranged around the central zone, is formed of a second material different from the first material, and has a second bending stiffness that is less than the first bending stiffness. Golf club head.   The golf club head of claim 1, wherein the first material has a first density, the second material has a second density, and the first density is greater than the second density.   The second material forms a plate-like face, and the first material has an insert fixedly coupled to the second material at or near the geometric center of the second material. The golf club head according to claim 1, which is formed.   4. The golf club head according to claim 3, wherein the plate-like face is configured to accommodate at least a part of the first material at or near the geometric center.   5. The plate-like face has a void formed so as to penetrate at or near the position of the geometric center, and the void is configured to accommodate at least a part of the first material. The described golf club head.   5. The golf club head according to claim 4, wherein the plate-like face has a cavity configured to receive at least a part of the first material at or near the geometric center.   The golf club head according to claim 6, wherein the cavity has a flange portion around the cavity, and the flange portion is configured to hold at least a part of the first material in the cavity.   The golf club head according to claim 4, wherein the plate-like face has a cavity protrusion configured to receive at least a part of the first material at or near the geometric center.   The cavity protrusion has an overhang formed around the cavity protrusion, the overhang configured to retain at least a portion of the first material in the cavity protrusion. The described golf club head.   4. The golf club head according to claim 3, wherein the second material is attached to the first material directly or indirectly by welding or an adhesive.   A cavity cap formed in the second material, wherein the first material forms a plug that is inserted into the cavity cap, and the cap is fixedly coupled to the plate-like face. 3. The golf club head according to 3.   The golf club head according to claim 11, wherein the cap is attached to the plate-like face by welding or an adhesive.   The golf club head of claim 11, wherein the plug is attached to an inner surface of the hollow cap.   The golf club head of claim 1, wherein the central zone is formed of a portion of the second material.   The golf club head of claim 1, wherein the first material comprises tungsten or stainless steel, and the second material comprises titanium.   The golf club head according to claim 1, wherein a peripheral zone is formed concentrically around the intermediate zone.   The golf club head of claim 16, wherein the surrounding thorn is formed from the second material or the first material.   The golf club head of claim 16, wherein the peripheral zone is formed from a third approval that is different from the first material and the second material, respectively.   The golf club head of claim 16, wherein the surrounding zone is thicker than the intermediate zone.

Images