JP4563062B2 - Metal wood club with improved striking face - Google Patents

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 having a high coefficient of restitution is aligned with a predetermined orientation.

  It is well known that golf club designs are complex. The specifications of each club component (i.e., club head, shaft, hosel, grip, etc.) are directly linked to the performance of the club. 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, face progression, face size, sole curvature, center of gravity, 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 coupling means with the shaft, the peripheral weight of the club head face or body, 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 causes the golf ball to exert a force on the golf ball that is several times the order of gravity. 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 0.10 inches, thereby ensuring the 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 the 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 coefficient of restitution changes according to the collision position of the club face. Furthermore, the accuracy of conventional clubs is highly dependent on the impact location.

F. Wemer and R.W. Greig's "How to Golf Clubs Really Works and How to Optimize The Design", Chapter 4, pp17-21 (2000), shows the distribution of hitting points on the face of the driver club in the direction from high to low to high heel. It reports that it follows an elliptical pattern along. The size of the hitting point distribution depends on the golfer's handicap. The player with a small handicap has a smaller elliptic distribution, and the player with a large handicap has a larger elliptic distribution. The author has patented a golf club with an elliptical striking face that aligns from high toe to low heel. See Patent No. 5,366,223 , issued in November 1994, “Golf Club Face for Drivers”. However, it is not taught to match the coefficient of restitution of the golf club head to the ball governor pattern.

  The present invention relates to a golf club head adapted to a shaft attachment. The head includes a striking face and a body. The striking face has a shape and size that includes at least an inner zone and a concentric intermediate zone. The inner thorn has a relatively large bending stiffness and the intermediate zone has a smaller bending stiffness. Preferably, the inner zone is shaped with a major axis and a minor axis, the major axis being substantially aligned in the direction from high heel to low toe. The inner zone may be elliptical or substantially square quadrilateral. The inner zone and the intermediate zone may have the same shape or different shapes.

  Such a configuration of the inner zone and the intermediate zone creates a region of relatively high bending stiffness in the direction from high heel to low toe, resulting in a large repulsive force in the direction from high toe to low heel. That is, this configuration forms a bending stiffness gradient along the direction from high toe to low heel, and has a favorable effect for adjusting the repulsive force or coefficient of repulsion in this direction. This region of improved coefficient of restitution is beneficially consistent with a golfer's typical ball impact pattern.

  The club head of the present invention defines a high COR measurement zone such that the smallest COR is at least 93% of the peak COR in the measurement zone. The measurement zone is defined by a rectangle measuring 0.5 inch × 1.0 inch, and the COR value is measured at the corner of the rectangle, the midpoint of the side, and the geometric center. The geometric center of the measurement zone preferably coincides with the geometric center of the club face.

The above is realized by providing the inner zone with the first bending stiffness and providing the intermediate zone with the second bending stiffness. Bending stiffness, multiplied by the cube of the zone thickness (t) to the Young's modulus i.e. modulus (E), i.e., defined by Et ^3. The first bending stiffness is considerably larger than the second bending stiffness. As a result, at the time of the ball collision, the intermediate zone is considerably deformed to propel the ball.

  In one embodiment, the first bending stiffness is at least three times the second bending stiffness. In other embodiments, the first bending stiffness is 6 to 12 times the second bending stiffness. More preferably, the first bending stiffness is greater than 25000 lb-in. Most preferably, the first bending stiffness is greater than 55000 lb-in. Preferably the second bending stiffness is less than 16000 lb-in. More preferably, the second bending stiffness is less than 10,000 lb-in.

  Since the bending rigidity depends on the characteristics and thickness of the material, the following method can be employed to realize a substantial difference in rigidity between the first bending rigidity and the second. (1) Use different materials for each part. (2) Use different thickness for each part. (3) Use different materials and different thicknesses for each part.

  The golf club head may further include a peripheral zone between the intermediate zone and the body of the club. In one embodiment, the bending stiffness of the peripheral zone is a third bending stiffness that is at least three times greater than the second bending stiffness.

  In the club heads discussed above, the inner zone, intermediate zone, and additional surrounding zone can be any shape having a major and minor axis, for example, oval, rhomboid, diamond-shaped, one or more rounded corners It can take other quadrilateral shapes. These zones may also be substantially parallelograms. Further, the volume of the internal cavity of the club head can be greater than about 100 cubic centimeters, and more preferably the volume is greater than about 300 cubic centimeters. In other words, the club head according to the present invention can be employed as a driver club or a fairway club. Furthermore, the inner, intermediate and surrounding zones may have different thicknesses.

  Another feature of the present invention is that the center of gravity of the club head is arranged in relation to an orthogonal coordinate system. The origin of the Cartesian coordinate system coincides with the geometric center of the striking face. The X coordinate is a horizontal axis at a position in contact with the geometric center of the hitting face, and the heel direction of the club is the positive direction. The Y axis is another horizontal axis orthogonal to the X axis, and the positive direction is the back direction of the club. The Z axis is a vertical axis orthogonal to the X axis and the Y axis, and the positive direction is the crown direction of the club. The center of gravity is preferably at a lower position behind the geometric center of the face.

  In one embodiment, the center of gravity is about −0.050 inches to about −0.150 inches from the geometric center along the Z axis, and more preferably about −0.110 inches. The center of gravity is preferably about + -0.050 inches away from the geometric center along the X axis, more preferably about + -0.015 inches. The center of gravity is preferably about +2.0 inches away from the geometric center along the Y axis, more preferably about +1.35 inches.

  The striking face may include a face insert and a face support. The face support defines a cavity for receiving the face insert. The striking face further has at least one side wall, which may form part of the partial sole of the crown. Preferably, the inner zone is located on the face insert and the intermediate zone is located partly on the face insert and partly on the face support.

  Referring to FIGS. 1-5, a first embodiment of a golf club head 10 of the present invention is shown. The club head 10 includes a shell 12 with a main body 14, a striking face 16, a toe portion 18, a heel portion 20, a sole plate 22, a hosel 24, a bottom portion 26, a crown portion 28, and a back surface portion 29. The sole plate 22 fits in a retracted portion 30 (shown in FIG. 5) of the bottom portion 26 of the main body 14. Shell 12 and sole plate 22 form an internal cavity 31 (shown in FIG. 5). The striking face 16 has an outer surface 32 and an inner surface 34. External surface 32 is generally smooth except for external grooves (not shown for convenience of explanation). Preferably, the inner surface 34 includes a bulge area or a depression area to vary the striking face thickness. This point will be described below and with reference to FIGS.

  A golf club shaft (not shown) is attached to the hosel 24 and disposed along the shaft axis SHA. The hosel may extend to the bottom of the club head and may terminate at a point between the top and bottom of the head. The hosel may also terminate flat with the top or may extend into the head cavity.

  The inner cavity 31 of the club head 10 may be a cavity and may alternatively be filled with foam or other low specific gravity material. Inner cavity 31 preferably has a volume greater than 100 cubic centimeters, and more preferably has a volume greater than 300 cubic centimeters. In other words, the club head according to the present invention can be employed as a driver club or a fairway club. Preferably the mass of the club head of this invention is greater than 150 grams and less than 250 grams.

  With reference to FIGS. 1 and 3-3D, the face 16 includes an inner zone or portion 36, an intermediate zone or surrounding portion 38 adjacent to the inner zone 36, and an additional surrounding zone or outer portion 40. The intermediate zone 38 preferably surrounds the inner zone 36 and the surrounding zone 40 preferably surrounds the intermediate zone 38. The inner thorn 36 is a continuous zone located on the striking surface and includes the geometric center (GC) of the striking face. As shown, the inner zone 36 and its concentric zones are generally elliptical, with the major axis in the direction from high heel to low sole. As used herein, the term “elliptical” or “elliptical” means a non-circular shape that has a major axis and a minor axis, but is not limited to any quadrilateral, geometric ellipse, 1 or Includes quadrilaterals with rounded corners and asymmetric ellipses. The term “coaxial” refers to a shape that substantially circles or surrounds another shape. The “major axis” is defined as the axis that coincides with the longest of the two lines drawn between the start and end points without traversing the perimeter of the shape. The “short axis” is orthogonal to the long axis near the center point.

  The major axis of the inner part 36 forms an angle θ with respect to the shaft axis SHA. Preferably, the angle θ is between about 10 ° and about 60 °, more preferably between about 20 ° and about 50 °, and most preferably between about 25 ° and about 45 °. Further, the ratio of the length of the major axis to the minor axis is preferably greater than 1.0, more preferably greater than about 6.0.

Preferably, the zones 36, 38, 40 are concentric with each other within the striking face 16. Inside zone 36 has a first thickness _{T 1.} The intermediate zone 38 has a second thickness _{T 2.} First thickness _{T 1} is greater than the second thickness _{T 2.} Typically, the peripheral zone 40 is thicker than the intermediate zone 38 when the club head is cast. Alternatively, the striking face may be forged. However, the present invention is not limited to any manufacturing method. T ₁ can be about 1.5 mm to about 7.5 mm, and T ₂ can be between about 0.8 mm and about 3.0 mm. Preferably, the first thickness _{T 1} is about 4 times to about 1.5 times the second thickness _{T 2.}

By setting the relationship between the thicknesses of the zones 36, 38, and 40, a predetermined relationship can be established with respect to the bending rigidity of each zone. In the case of a club made of a single material such as titanium or titanium alloy, the thickest region corresponds to the portion having the greatest bending rigidity. The bending rigidity (FS) of each part is FS = E (t ³ )
Defined by
Here, E is the elastic modulus, ie, Young's modulus, of the portion, and t is the thickness of the portion. The Young's modulus of titanium is about 16.5 × 10 ⁶ lbs / in ² and the thickness is typically measured in inches. This is because FS has a unit of lb · in in this application.

Internal Zone 36 has a first bending stiffness FS _1. Intermediate zone 38 has a second flexural rigidity FS _2. Peripheral zone 40 has a third flexural rigidity FS _3. The predetermined relationship between the parts is that the first bending stiffness FS ₁ is much larger than the second bending stiffness FS _{2 and} , in addition, the third bending stiffness FS ₃ is much larger than the second bending stiffness FS _2. . Preferably, three times greater than the stiffness FS ₂ first bending stiffness FS ₁ is at least a second bend. That is, (FS ₁ / FS ₂ )> = 3. When the above-described bending stiffness ratio is less than 3, the inner zone maintains excessive deformation upon impact and reduces club accuracy. More preferably, the first bending stiffness FS ₁ is about 6 times to about 12 times the second bending stiffness FS ₂ . Most preferably, the first bending stiffness FS ₁ is greater than about 8 times the second bending stiffness FS ₂ . Preferably, more than twice of the third flexural rigidity FS ₃ is at least a second flexural rigidity FS _2. That is, (FS ₃ / FS ₂ )> = 2.

Alternatively, the flexural rigidity FS ₁ , FS ₂ , or FS ₃ is equal to two adjacent zones as long as the preferred ratio (FS ₁ / FS ₂ )> = 3 or (FS ₃ / FS ₂ )> = 2. May be determined.

The zone thicknesses T ₁ and T ₂ may be constant within the zone as illustrated in FIGS. 3A and 3B, or may be variable within the zone as illustrated in FIGS. 3C and 3D. Also good. To determine the FS, a weighted average thickness is calculated as the thickness changes. The determination of FS when the thickness changes or when the material is not uniform is described in the original application and is incorporated herein by reference.

  In the club 10 (as shown in FIGS. 3-3D), the above-described bending rigidity relationship is achieved by selecting a predetermined material having a specific elastic modulus and changing the thickness of the zone. In other embodiments, the flexural stiffness relationship can be achieved by changing the materials of each other so that each zone has a different modulus and thickness. As a result, the thickness of each zone may be the same or different depending on the elastic modulus of the material of each zone. In addition, a thickness parameter can be obtained by obtaining a desired bending rigidity ratio using the structural rib and the reinforcing plate.

In terms of numerical values, the first bending rigidity FS ₁ is preferably larger than 25000 lb-in. If the first bending rigidity is smaller than 25000 lb-in, excessive deformation of the inner region occurs at the time of collision, and the accuracy decreases. More preferably, the first bending stiffness FS ₁ is greater than 55000 lb-in. Preferably the second bending stiffness FS ₂ is less than 16000lb-in. When the second bending stiffness is greater than 16000 lb-in, the resulting ball speed decreases. More preferably rigid FS ₂ second bend is smaller than 10000lb-in, and most preferably less than 7000lb-in.

  Referring to FIG. 3, the area of the inner zone 36 is preferably between about 15% and about 60% of the outer surface region 32. The ratio of the face region is calculated by dividing the area of each zone 36, 38, 40 by the area of the outer surface 32. Note that the face area of the outer surface 32 is equivalent to the total area of the zones 36, 38, 40. When the inner zone 36 is less than 15% of the total face area, the accuracy will decrease. When the inner portion 36 is greater than 60% of the face area 32, the coefficient of restitution will decrease.

Referring to FIG. 1, the club head 10 further has a predetermined relationship with the orthogonal coordinate system in which the center of gravity of the club head is located on the striking face 16 and coincides with the scientific center GC of the face 16. It is manufactured. The striking face 16 includes a vertical center line VCL and a horizontal center line HCL perpendicular thereto. The geometric center GC of the striking face 16 is located at the intersection of the center lines VCL and HCL. VCL and HCL are coaxial with the X-axis and Z-axis of the Cartesian coordinate system, as will be described below. Preferably, the GC of the inner zone 36 is spaced from the GC of the striking face 16 by a distance less than about 0.10 inches, more preferably less than about 0.05, and most preferably less than 0.025 inches. They are separated by a distance. The GC of the inner zone 36 may coincide with the GC of the striking face. The GC of the inner zone 36 can be defined as the intersection of the major and minor axes of the zone.

The orthogonal coordinate system is defined as the geometric center of the hitting face and the origin coincide. The striking face is not a straight surface but a curved surface depending on the bulge and roll radii. The X axis is a horizontal line in contact with the geometric center of the hitting face, and the positive direction is the heel direction of the club. The Y axis is another horizontal line orthogonal to the X axis, and the positive direction is the back direction of the club. The Z axis is a perpendicular line orthogonal to the X axis and the Y axis , and the positive direction is the crown direction of the club.

  When the club head is placed on a flat surface (with a natural loft angle), the center of gravity is preferably located below the geometric center of the face. In one embodiment, the center of gravity of the club head 10 is about −0.050 inches to about −0.150 inches from the geometric center along the Z axis, more preferably about −0.110 inches. Yes. The center of gravity is preferably about + -0.050 inches away from the geometric center along the X axis, more preferably about + -0.015 inches. The center of gravity is preferably about +2.0 inches away from the geometric center along the Y axis, more preferably about +1.35 inches.

  The center of gravity of such a club head can be realized by controlling the shape and dimensions of the club head and adding a predetermined weight to the sole plate or the club head. Other known weighting operations can be used to realize the center of gravity position of the present invention as described above.

  FIG. 6 shows another embodiment of the present invention. The central zone 36 is generally a square quadrilateral, the opposing sides are generally parallel, and the angles of adjacent sides are rounded. More specifically, the acute angle α of the central zone 36 is preferably between 40 ° and 85 °. Further, the major axis of the central zone 36 makes an angle β with respect to the HCL as shown, which is preferably between 5 ° and 45 °. The long axis is a line connecting two acute angles of a parallelogram. Similar to the embodiment described above, the intermediate zone 38 surrounds the central zone 36, and the relative thickness and FS ratio of the zones 36, 38 satisfy the relationship described above.

As shown in FIG. 7, the central zone 36 may be an ellipse. However, the intermediate zone 38 is generally a parallelogram. Conversely, the central zone 36 may be a parallelogram as a whole and the intermediate zone 38 may be a parallelogram. Furthermore, the width of the central zone 38 may change as shown .

According to another aspect of the invention, the striking face 16 may include a face insert 42 and a face support 44 as shown in FIG. In this embodiment, the striking face 16 is distinguished from the crown 28, the toe 18, the sole 22 and the heel 20 by a dividing line 46. The central zone 36 is preferably located behind the face insert and is generally a parallelogram, as shown. The intermediate zone 38 is disposed partially in contact with the face insert 42 and partially in contact with the face support 48 as indicated by 38 ₁ and 38 ₂ . The transition zone 37 varies in thickness and is located between the central zone 36 and the intermediate zone 38. Preferably, the thickness of the central zone 36 is made thinner than the thickness of the intermediate zone 38 by the transition zone 37. As a result, it is possible to reduce the stress / strain of any portion caused at the time of the collision of the ball due to the sudden change in the thickness. The face support 44 defines a hole 48 that is bounded by a rim 50. The face insert 42 is fixed to the face support 44 by welding the rim 50 or its periphery. To determine the FS ratio of this embodiment, the internal zone FS ₁ includes both zone 36 and zone 37.

According to another aspect of the invention, the face insert may include one or more side walls, which may form part of a crown or sole. As shown in FIG. 9, the face insert 52 includes a central zone 36, a transition zone 37, a portion of the intermediate zone 38, a partial crown portion 54 and a partial sole portion 56. The club head 10 thus defines a cavity 58 that is sized and shaped to receive the face insert 52. The face insert 52 is preferably welded to the club head 10. The face insert 52 constitutes the striking face 16 together with the face support 60. Similar to the embodiment of FIG. 8, the intermediate zone 38 is designated 38 ₁ , 38 ₂ and partially contacts the face insert 52 and partially contacts the face support 60.

[Example]
In this example, the striking face has the following configuration. The central zone 36 is substantially a parallelogram as shown in FIG. Measurement of the long axis is about 3 inches, minor axis is a thickness _{T 1} at about 0.75 inches to about 0.120 inches. The central zone 36 has a concentric transition zone 37 that is similar in shape to the central zone 36. Intermediate zone 38 surrounds the central zone and the transition zone, the thickness T ₂ are are 0.080 inches and comprising a remaining portion of the face strike zones. In this example, the surrounding zone 40 is not included. The major axis of the zone 36 substantially coincides with the major axis of the zone 38, which makes an angle θ of about 50 ° with the shaft axis. Further, zones 36 and 37 include approximately 18% of the total face surface area. A single uniform material is used, for example a titanium alloy with a Young's modulus (E) of about 16.5 × 10 ⁶ lbs / in ² . In this example, the ratio of (FS ₁ / FS ₂ ) is 3.4. However, FS ₁ includes both zones 36 and 37 and FS ₂ includes zone 38.

  Test results were generated using a computer approach including a finite element analysis model. The following hypothesis was used in the computer model. That is, the club head loft is 9 °, the club head mass is 195 grams, and the club head material is 6AL-4V titanium alloy. The golf ball used in this model was a two-piece solid ball. Finite element return was used to predict ball launch conditions, and trajectory model was used to predict distance and landing area. The impact conditions used for the club coefficient of restitution (COR) test were in accordance with the USGA Golf Rules, and in particular, Rule 4-1e, Appendix II, 2nd Edition, February 8, 1999.

  The distribution of the coefficient of restitution (COR) is shown in FIGS. 10 (b) and 10 (c). Lines indicate contour lines. This is similar to the contour line of the topology diagram and weather map, and shows a constant COR (hereinafter referred to as iso-COR, equal COR line). The innermost contour indicates the largest COR area on the striking face, and the outer contour indicates a smaller COR area on the striking face. FIG. 10B shows an equal COR contour of a conventional golf club having a uniform thickness, and FIG. 10C shows an equal COR contour of the club of the invention described in this example.

COR, or coefficient of restitution, is one technique for measuring the repulsive force of a ball. 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 generally depends on the shape and characteristics 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.

  The equal COR contour generated by computer analysis is shown within a rectangle measuring 0.5 inches by 1.0 inches, as is typically used in the art. Within this rectangle, a relatively large and uniform COR was obtained with the inventive club. This COR value is measured at eight points of a rectangle. That is, the corner of the rectangle, the midpoint of the side, and the geometric center of the rectangle. Further, the geometric center of the rectangular measurement zone is preferably coincident with the geometric center of the club striking face. In this example, the smallest COR in the measurement zone is 0.828, and the maximum value is 0.865. According to the present invention, the smallest COR is within 93% of the maximum COR. This advantage can provide a striking face with a substantially uniform COR and a large “sweet spot”.

  The equal COR contour of the conventional club shown in FIG. 10B substantially follows an elliptical pattern. Furthermore, the center of the innermost COR contour line having the largest COR value is deviated from the geometric center of the rectangular measurement zone. The major axes of these contours are substantially horizontal.

  The equal COR contour line of the club of the present invention also follows an elliptical pattern as shown in FIG. The long axis of the pattern does not coincide with the horizontal center line HCL of the striking face. According to the test results, the long axis of the equal COR contour pattern forms an angle δ with respect to the HCL. The angle δ is at least 5 °, more preferably 7 °, from high toe to low heel. The long axis of the central zone 36 of the largest FS is substantially from the high heel to the low toe, while the long axis of the iso COR contour is in a substantially different direction, ie from the high toe to the low heel. This advantageously matches the hitting position distribution on the golfer's hitting face as described above. Furthermore, the center of the innermost equal COR contour is closer to the geometric center of the rectangular measurement zone, resulting in a larger maximum COR value.

  Without being limited to a particular theory, the inventor of the present application is that when a thick or high FS elliptical region is at or near the center of the striking face and a thin or low FS region wraps around it, It has been discovered that the iso-COR contour generally forms an ellipse with the major axis of the iso-contour line forming a predetermined angle with the major axis of the elliptical region having a large thickness or high FS. With such a configuration of the inner zone and the intermediate zone, it is possible to form a relatively large area of bending elasticity along the high heel to the low toe that forms a zone of high repulsion force in the direction from the high toe to the low heel. In other words, in this configuration, a bending rigidity gradient can be provided from the high toe toward the low heel, and a repulsive force or a high restitution coefficient can be applied in this direction. Such an area of improved coefficient of restitution beneficially matches the ball hitting pattern on a typical golfer hitting face.

  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 other embodiments of the present invention. Included as The scope of the invention is defined by the claims.

1 is a front perspective view of a toe side of an embodiment of a golf club head of the present invention. FIG. 2 is a rear perspective view of a heel side of the golf club head of FIG. 1. FIG. 2 is a proof diagram of the golf club head of FIG. 1. FIG. 3 is a cross-sectional view of the face along line 3A-3A of the golf club head of FIG. 3 is a cross-sectional view of the face taken along line 3B-3B of the golf club head of FIG. 3B is a cross-sectional view of the alternative of FIG. 3A. 3C is a cross-sectional view of the alternative of FIG. 3B. FIG. 2 is a plan view of the golf club head of FIG. 1. FIG. 2 is a bottom perspective view of the golf club head of FIG. 1. It is explanatory drawing of the internal zone and intermediate | middle zone of a substantially parallelogram shape. It is explanatory drawing of the internal zone and intermediate | middle zone of the shape of substantially parallelogram and an ellipse. It is a front exploded view of another embodiment of the present invention. It is a front exploded view of another embodiment of the present invention. It is a figure which compares the result of the comparative example of this invention, and compares the equal COR outline of the conventional golf club head and the Example of this invention.

Claims (8)

A face insert,
With a face support,
These face inserts and face supports form a striking face,
The striking face has an inner zone having a parallelogram shape as a whole, and a thin intermediate zone over emissions from the internal zone disposed therearound,
The internal zone has a long axis substantially along the direction from high heel to low toe and has a first bending stiffness, and the intermediate zone has a second bending stiffness,
The first bending stiffness is greater than the second bending stiffness; the first bending stiffness is greater than the second bending stiffness and is a long axis substantially along the direction from the high heel to the low toe The internal zone is such that the restitution coefficient of the area of the typical ball hitting distribution pattern of the hitting face substantially along the direction of high toe to low heel is greater than the restitution coefficient of its surroundings. ; golf club head the long axis of the internal zone having the shape of the parallelogram, characterized in that the forming a first angle of between 50 ° from 20 ° to the shaft axis of the club head.   The golf club head of claim 1, wherein the face support defines a cavity sized and shaped to receive the face insert.   The golf club head according to claim 2, wherein the cavity is disposed in contact with the hitting face.   The golf club head of claim 1, wherein the golf club head defines a cavity sized and shaped to receive the face insert.   The golf club head of claim 1, wherein the face insert has at least one wall.   The golf club head according to claim 5, wherein the at least one wall portion partially forms a crown portion.   The golf club head according to claim 5, wherein the at least one wall portion partially forms a sole portion. The golf club head of claim 1 , wherein the first angle is between 25 ° and 45 °.

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