JP2008114080A - Golf club head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a golf club head, with increased playability and forgiveness. <P>SOLUTION: The hollow golf club head 1, provided with a concave portion 20, comprises a metallic portion and a light-weight portion of plastic or the like. The concave portion allows the club designer to make a club head having very thin portions, while still maintaining the requisite structural integrity. A convex bulge 22 is provided to house weight inserts for increasing playability. The metallic portion of the club head has an appearance of a frame for housing several light-weight inserts. These light-weight inserts may be housed in a crown 13, a skirt 14, and a sole 12. The club head may be formed by co-molding, eliminating the need for welding or adhesives, freeing mass to be used in more beneficial ways. The club head may be large so as to increase playability and forgiveness. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a golf club, and in particular, the present invention relates to a large wood type golf club head with improved physical attributes.

  Note that this application is a continuation-in-part of US patent application Ser. No. 11 / 363,098 filed on Feb. 28, 2006, which is currently pending. This US patent application includes 1) currently pending 2005 patent application. US Patent Application No. 11 / 110,733 filed on April 21, 2005, and 2) currently pending US Patent Application No. 11/180, filed July 13, 2005 , 406 part continuation application. Each of these patent documents is cited by reference, and the entire description is made a part of this specification.

  Golf club heads are sold in a wide variety of forms and types, such as wood or metal types (including drivers and fairway wood), iron types (including wedge type club heads), utility types, specialty types and putter types. ing. Each of these styles has a defined function and composition or configuration. The present invention relates primarily to hollow golf club heads, such as wood type and utility type golf club heads (commonly referred to as wood type golf club heads).

  Wood-type golf club heads generally have a front or striking face, a crown, a sole, and an arc skirt that includes a heel, a toe, and a back. Crowns and skirts are sometimes referred to as “shells”. The front face forms an interface with the golf club and strikes it. A plurality of grooves, sometimes called “score lines”, may be provided on the face to help spin the ball and for decorative purposes. The crown is generally configured to provide the golfer with a specific look and structural rigidity to the striking face. The golf club sole contacts and interacts with the ground during a swing.

  In designing and manufacturing wood type golf clubs, it is necessary to pay close attention to the construction of the club head. Among the many factors that must be considered are material selection, material handling, structural stiffness and overall geometric design. Exemplary geometric design considerations include loft angle, lie angle, face angle, horizontal face bulge, vertical face roll, face size, sole curvature, center of gravity, and overall head weight. The internal design of the club head can be tailored to achieve specific characteristics, for example by providing a hosel or shaft mounting means, a peripheral weight applied to the face or club head body, and a filler in the hollow club head. The club head is typically formed of stainless steel, aluminum or titanium, cast, stamped, for example by forming sheet metal with pressure, forged or any two or three of these processes. It is formed by the above combination. Club heads are welded together or otherwise joined together to form a hollow head, as is often seen with club heads designed with inserts, such as sole plates or crown plates. May be formed. The multi-part (multi-material) construction facilitates access to the cavity formed in the club head, thereby allowing attachment of various other components, such as internal weights or club shafts, to the head. The cavities may remain empty or may be partially or completely filled with foam, for example. Adhesive may be injected into the club head to collect and hold debris that may be present in the club head while providing the correct swing weight. In addition, club heads can be manufactured to a strict standard set by utilizing a multi-part structure due to problems in manufacturing an integrated club head to high dimensional tolerances.

  It is known to manufacture a wood type golf club with a metal material. These clubs were originally manufactured by casting primarily durable metals, such as stainless steel, aluminum, beryllium copper, etc., into a unitary structure having a metal body, face and hosel. As technology has advanced, it has become desirable to improve the performance of club faces, usually by using titanium materials.

  Given that a high percentage of amateur golfers are always trying to earn longer distances with their shots, the golf industry should offer a golf club specially designed with distance in mind. I tried to respond to this. The head size of wood-type golf clubs has increased, thereby increasing the moment of inertia of the golf club, and this high moment of inertia has increased the ability to resist torsion during off-center strikes. As wood-type club heads become larger, their center of gravity will move away from the face and be closer to the toe, resulting in a higher and higher right side than expected (right-handed) For golfers). This can be compensated by reducing the loft of the large club head. Since the center of gravity is further away from the hosel axis, these golf clubs may remain open on contact if the head is large, which induces a “slicing” effect (right-handed) In the case of a golfer, the ball moves to the right). While offsetting the head and / or incorporating a hook face angle can help compensate for this by making the face "right angle" upon impact, it must eliminate the "slicing" tendency.

  Another breakthrough technology in recent years that provides longer distances to the average golfer, while producing large golf clubs, is consistently casting thin shell thicknesses and lightweight materials such as titanium, magnesium and The use of a composite material is to keep the weight constant or even lighter. Also, the club face is steadily extremely thin. This is because when the face is thin, a value called a rebound coefficient (COR) is maximized. The greater the rebound of the face during impact, the more energy is transferred to the ball, thereby increasing the resulting shot distance.

  A known method of improving the weight distribution of a wood type club head to help reduce the golf club from being open when in contact with the ball is to use a weight on the cast body itself. Add or cleverly add a weight element at some point in the club. Many technical efforts have been made to incorporate weight elements into wood-type club heads. These weight elements are usually placed at specific locations that have a positive impact on the distance of the ball or overcome the shortcomings of specific golfers. As mentioned above, the main problem area for handicapped big golfers is the “slicing” tendency, which, in addition to deflecting the ball to the right, places a large spin on the ball, so overall The shorter shot distance becomes even shorter. In order to reduce this tendency, the present invention teaches placing the weight element directly in the club head. The placement of the weight elements is designed to reduce the spin of the ball and to give the ball flight a “draw” (right-to-left ball flight for right-handed golfers). This ball flight pattern is also designed to help golfers who are challenging distance. This is because a ball with a low spin rate generally rolls a longer distance after first contacting the ground than a ball with a high spin rate.

  The present invention relates to a large wood type golf club head with improved playability. The club head may be formed of a plurality of main body members constituting the inner volume portion. The first body member is made of a metallic material, and the first body member has a sole portion and a face portion. The second body portion is made of a very thin sheet of lightweight material such as plastic, composite or low density metal material. The second body portion comprises at least a portion of the club head skirt, the second body portion having one or more recessed portions extending into the interior volume of the club head. These indentations provide structural rigidity to the second body portion, which can be a very thin panel.

  The second body member may further include one or more convex bulges that extend away from the internal volume as a whole, but this is optional. An insert, such as a weight insert, may be positioned within the convex bulge. Careful positioning of the weight insert allows designers to improve the play characteristics of the golf club and tailor the club to a particular swing type. The first body member may form the majority of the club head sole, and the second body member may form the majority of the club head crown. By positioning the weight, the play characteristics of the golf club are further improved.

  The club head may have an auxiliary weight positioned very low and rearward when viewed from the striking face. The center point on the sole plate defines the lowest point of the club head, and in one embodiment, the center point positions the club head directly below the center of gravity when the club head is in a 59 ° lie angle. . The center of gravity of the auxiliary weight is positioned at a predetermined distance from the center point. Preferably, the center of gravity of each auxiliary weight is located at least 0.5 inch (12.7 mm) behind the center point, and for the first weight insert, at least from the center point toward the toe of the golf club head. 0.75 inch (19.05 mm), with the second weight insert located at least 0.75 inch (19.05 mm) from the center point toward the heel of the golf club head and maximum from the center point Located 0.25 inches (6.35 mm) above, the location of the auxiliary weight changes the traditional appearance of the golf club head by bulging out of the natural contour of the club head.

  The auxiliary weight may be arranged with reference to the point where the hosel center line intersects the sole plate. Next, this distance is measured from the rear surface of the striking face at the middle point to obtain the intersection. Preferably, with the club head at a 59 ° lie angle, each of the auxiliary weights is at least 0 inch toward either the heel or toe, at least 0.5 inches behind the intersection. Located at .75 inches (19.05 mm) and up to 0.25 inches (6.35 mm) above the intersection.

  The club head may include a combination according to the invention of geometric and physical features. For example, the club head may have a large striking surface area, a large face length and / or a large face height. By increasing the size of the striking face, the sweet spot becomes wider, thereby increasing the golf club's forgiveness and therefore easier to play.

  The club head may have a large depth as measured in the face-rear direction. By increasing the depth of the club head, the center of gravity moves backward, which also facilitates the club head to play. This feature of the invention can be quantified in a variety of ways, such as crown surface area. Preferably, the golf club head has a large crown surface area. To further promote these advantageous attributes, the crown may be tilted rearward from the striking face with at least a portion of the crown positioned below the center of gravity of the club head. Preferably, most of the periphery of the crown is disposed below the center of gravity (sole side) of the club head.

  The club head can be formed in various ways. One such method is simultaneous molding, that is, a manufacturing method in which two dissimilar materials are joined directly to each other by molding one of the materials into the other. For example, the metal portion of the club head may form at least a portion of a mold that is used to form the second portion of the club head from a lightweight material, such as a plastic or composite. . Other mold parts can also be utilized in connection with the metal portion of the club head. Simultaneous molding eliminates the need for welding or adhesives. Club head designers are free to use the mass occupied by these known attachment means in other more advantageous ways without increasing the overall mass of the club head. Such advantageous use of "freed-up" mass includes increasing the overall size of the club head, increasing the size of the sweet spot on the club head, and repositioning the club head center of gravity And / or producing a large moment of inertia.

  The present invention will be described with reference to the accompanying drawings. In the drawings, the same reference numerals indicate the same elements.

  Unless otherwise specified in the examples, or unless otherwise specified, numerical ranges, quantities, values and percentages for all other quantities, such as material quantities, moments of inertia, centroid positions and other quantities in the following part of the specification, are all Even if the term “about” is not explicitly stated with a value, quantity or range, it should be read as if the term “about” preceded. Thus, unless specified to the contrary, the numerical parameters set forth in the following description and claims are approximate values that vary depending on the desired characteristics that the invention seeks to obtain. Finally, rather than in an attempt to limit the application of the doctrine to the scope of the present invention as set forth in the claims, each of the numerical parameters is at least in light of the reported number of significant digits and is subject to conventional rounding techniques. Should be interpreted by applying.

  Although numerical ranges and parameters describing the scope of the invention are approximations, the numerical values set forth in any particular embodiment are reported as accurate as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their testing measurements. Further, when numerical ranges are described herein with varying limits, it is contemplated that any combination of these values, including the stated values, can be used.

  FIG. 1 shows a golf club head 1 of the present invention. The club head 1 has a main body 10 having a striking face 11, a sole 12, a crown 13, a skirt 14, and a hosel 15. The body 10 defines a hollow inner volume 16. Foam or other material may partially or completely fill the interior volume 16. The weight may partially or completely fill the inner volume 16. A weight may be provided in the inner volume portion 16, but whether or not to do so is arbitrary. The face 11 may be provided with grooves or score lines of various designs. The club head 1 has a toe T and a heel H.

  In the illustrated embodiment of FIG. 1, the club head 1 is composed of a plurality of body members that form an inner volume portion 16 in cooperation with each other. The first body member 101 has a sole portion and a face portion. The first body member 101 may include the entire face 11 and the entire sole 12. As a modification, either one or both of the face 11 and the sole 12 may be an insert bonded or bonded to the first body member 101. The club head 1 further includes at least one second body member 102 that is coupled or adhered to the first body member 101 along the skirt 14 in a known manner. The crown 13 may be an integral part of one of the main body members 101 and 102, or may be an insert coupled or bonded to one of the main body members 101 and 102. The second body member 102 has a recessed portion 20 that extends inwardly into the interior volume 16 when the body members 101, 102 are joined or bonded together. FIG. 2 is a diagram illustrating the second body member 102 as an example.

  The first body member 101 is preferably made of a metallic material such as stainless steel, aluminum or titanium. The material of the first body member 101 is selected so that it can withstand the stresses or strains that occur during a golf swing, including the stresses and strains caused by hitting a golf ball or the ground. The club head 1 may be designed to form a primary load support structure that can withstand such forces repeatedly. Other parts of the club head 1, such as the skirt 14, are less stressed and distorted, and advantageously, lighter, more weight effective auxiliary materials may be used instead of such other parts. Lightweight weight materials, such as low density metal alloys, plastics, composites, etc., also having a low density or equivalent density can be used in these areas, thereby advantageously allowing the club head designer to Can redistribute “saved” weights or masses to other more advantageous locations of the club head 1. These parts of the club head 1 may also be made thin, which promotes weight savings. Exemplary uses for this redistributed weight include increasing the overall size of the club head 1, a “sweet spot” of the club head (a sweet spot is the result of a desired golf shot when a golf ball is hit. Enlarging the size of the face 11 to be obtained), repositioning the center of gravity of the club head 1 and / or creating a large moment of inertia (MOI). . Inertia is the property of a substance that, if no external force is applied, the object remains stationary or in a uniform motion state. MOI is a measure of an object's resistance to angular acceleration about a given axis and is equal to the sum of the products of each element of mass in the object and the square of this element's distance from the axis. Thus, as the distance from the axis increases, the MOI increases, thereby increasing the club's tolerance to off-center strikes. This is because there is little energy loss during impact due to club head twisting. By transferring or rearranging the mass around the club head, the sweet spot is expanded, resulting in a more tolerant club. Maximizing the club head size and transferring as much mass as possible to the outermost area of the club head 1, such as the heel H, toe T or sole 12, maximizes the chance of expanding the sweet spot or creating a large MOI This makes the golf club more interesting and more tolerant.

  The second body member 102 is lightweight, which provides an opportunity to free up weight for some advantageous location without shifting the center of gravity of the club head downward and increasing the overall weight of the club head 1. If the wall thickness of the second body member 102 is in the minimum range of the desired thickness, a reinforcing body layer may be added to the critical area when the second body member exhibits deformation. These advantages can be further promoted by making the second body member 102 thinner. These thin panels preferably have a concave portion 20 so that the structural integrity of the club head 1 is maintained. By providing these concave portions 20, the second body member 102 can withstand large stresses in both the longitudinal and lateral directions without undergoing permanent set or affecting the original appearance. Thereby, the structural soundness of the club head 1 is maintained. The preferred thickness of the first body member 101 is 0.03 inches (0.76 mm) to 0.05 inches (1.27 mm), and the preferred thickness of the second body member 102 is 0.015 inches. (0.381 mm) to 0.025 inch (0.635 mm). Preferably, the concave portion 20 occupies at least 10 cubic centimeters. More preferably, the concave portion 20 occupies at least 25 cubic centimeters. The club head 1 may be of virtually any size, but is preferably a statutory club head. A plurality of concave portions 20 may be used for the club head 1. For example, the concave portion 20 having a uniform size or gradually changing size may be provided on the toe, heel, back, or the like.

  FIG. 3 is a sectional view taken substantially perpendicular to the face 11 of the second club head 2 of the present invention, and FIG. 4 is a bottom view of the club head 2. The concave portion 20 is preferably not visible to the golfer when addressing. In addition to the concave portion 20, the second body member 102 further has a convex bulge 22 that extends away from the inner volume 16 as a whole. The insert 23 may be positioned within the convex bulge. The insert 23 is not visible from the outside of the club head 2 and is thus illustrated using a dashed line. In a preferred embodiment, the insert 23 is a weight insert. Since the bulge 23 is convex, the weight can be positioned so as to maximize the mechanical advantage that the bulge imparts to the club head 2. As shown in FIG. 4, the club head 2 may have, for example, a plurality of convex bulges 22 on the heel side and the toe side of the club head 2. The club designer can place the insert 23 in the bulge 22 as desired. The mass of the inserts should be substantially equal to each other. As a variant, one of the inserts may have a larger mass than the other inserts. This may be advantageous for designing a club to correct a hook swing or a slice swing. A preferred mass range for the weight insert 23 is 1 gram to 50 grams.

  As shown in FIG. 3, the first main body member 101 may constitute most of the sole 12, and the second main body member 102 may constitute most of the crown 13. This advantageously removes most of the mass from the top of the club head 2. In this embodiment, the first body member 101 has a mounting perimeter 18 that extends around its edges. The second body member 102 is coupled or bonded to the first body member 101 along the mounting perimeter 18. The first main body member 101 and the second main body member 102 form the inner volume portion 16 in cooperation. The mounting perimeter 18 preferably has a step that defines two mounting surfaces 18a, 18b. As shown, the second body member 102 may be bonded or bonded to both of these mounting surfaces 18a, 18b to help ensure a strong bond or bond between the body members 101, 102. .

  The body members 101, 102 can be formed by various methods, but in a preferred method, the entire club head shell (first body member 101) is formed in a known manner and the material is removed to form the second body. An opening is formed through which the member 102 can be bonded or bonded. The opening can be formed in any desired manner, for example with a laser. The second body member 102 can be joined to the first body member 101 in a variety of ways, for example, by coupling or a snap fit associated with the coupling. When using a composite material with a concave insert, it is preferable to mold 6 plies of 0/90/45 / −45 / 90/0.

  5-9 illustrate additional features of the present invention. In the embodiment shown in these figures, the club head 1 comprises a crown portion 13, a sole 12, a heel portion H, a toe portion T, a skirt portion 14 connecting the heel portion H to the toe portion T, a front face 11 and A hosel 24 extending from the heel portion H is included. The club head 1 may be formed by joining sheets together, for example by welding or casting, preferably from a titanium alloy. The crown portion 13 may be made from a material such as a carbon fiber composite, polypropylene, kevlar, magnesium or a thermoplastic resin. The hosel 24 has a bore that defines a central axis C / L.

  As best shown in FIG. 9, the club head 1 of the present invention has a center of gravity G at the highest peak and in a lower position. The location of the center of gravity G is offset by the arrangement of two auxiliary weights, a toe side auxiliary weight 26 and a heel side auxiliary weight 28, both of which are partly the traditional of a golf club head. Located outside of the general overview. As shown in FIGS. 5 to 9, the location of the two auxiliary weight elements 26 and 28 is determined by the relationship between these distances from the determined contact point. When the club head is at a lie angle φ of 59 °, the lowest contact point of the sole 12 is at a center point C just below the center of gravity G.

  In the present specification, a method for determining the location of the auxiliary weights 26 and 28 will be described. As shown in FIG. 8, the center line C / L of the hosel 24 intersects the sole plate 12 at a distance D from the rear surface of the front face 11. When a line BB that is substantially parallel to the rear edge of the club head is extended (while maintaining the distance D), a line A-A and an intersection point P that are perpendicular to the midpoint of the front face 11 and that extend rearward from the midpoint of the front face 11 Arise. Line AA passes through the center of the club head 1 and directly below the center of gravity G of the club head. This intersection point P can also be determined by the intersection of the line AA and the vertical plane located at the intersection of the hosel center line C / L and the sole 12. The center of gravity C / G of each of the auxiliary weights 26 and 28 is located at a distance W of at least 1.50 inches (3.81 cm) behind the intersection P and is the lowest contact point that is the center C of the sole plate 12. Is located at a distance Z of up to 0.25 inches (6.35 mm), and each auxiliary weight is a distance Y1 closer to the toe T for the toe side auxiliary weight 26, and for the heel side auxiliary weight 28 It is located at a distance of at least 0.75 inches (19.05 mm) in the opposite direction from the line AA, which is the distance Y2, near H.

  With respect to the present invention, the location of the auxiliary weights 26 and 28 can also be determined by measuring from the center point C. The center of gravity of each auxiliary weight 26, 28 is a maximum of 0.25 inches above the center point C at a distance X of at least 0.50 inches (12.7 mm) rearward along the line AA from the center point C. However, in the opposite directions from the line AA, the toe side auxiliary weight 26 is located closer to the toe T, and the heel side auxiliary weight 28 is located closer to the heel H at a distance Z of a minimum of 0.75 inches. . Thus, each auxiliary weight 26, 28 is located at a minimum of 0.90 inches (22.86 mm) from the center point C.

  The auxiliary weights 26, 28 may be selected from a plurality of weights designed to provide specific adjustments to the club head weight. The auxiliary weights 26 and 28 may be welded in place or attached with an adhesive. The weights 26, 28 may generally be made of heavy inserts, such as steel, nickel or tungsten. Preferably, the body of the club head 1 is made of titanium and the crown portion 13 is made of a lightweight material such as carbon fiber composite, polypropylene, kevlar, thermoplastic, magnesium or some other suitable lightweight material. . A preferable volume of the club head 1 is 350 cc to 460 cc. The auxiliary weights 26 and 28 preferably have a mass of 2 to 35 grams, more preferably 10 to 35 grams. It is well known that a wide range of golfers can be accommodated by changing parameters such as shaft deflection location, shaft weight, shaft stiffness, face angle and club loft. However, the present invention addresses the most important launch considerations in optimizing the mass characteristics (center of gravity and moment of inertia) of the club head by creating a center of gravity that is low, rear and wide in center. The club head 1 of the present invention typically surrounds an area of the club head that is not used for weighting. This is because such an area adversely changes the club head's traditional view. With this club head 1 design, a portion of the auxiliary weights 26, 28 can bulge out of the normal profile of the club head.

  FIG. 10 is a bottom view of the golf club head 1 of the present invention. The skirt 14 has an opening 30 near the rear part of the club head 1. An insert 35 is positioned in the opening 30 in a known manner, for example by means of the mounting perimeter 18 and cooperates with the inner volume 16. Preferably, the insert 35 is made of a lightweight material, such as a composite or polymer material. By using the lightweight insert 35, the mass of the club head is essentially shifted toward the sole 12 of the club head 1. This also allows the weight member to be provided to achieve a specific moment of inertia and / or location of center of gravity while maintaining typical values for overall club head weight and mass.

  FIG. 11 is a bottom view of the golf club head 1 of the present invention. In addition to the auxiliary weights 26, 28, the club head 1 has an insert 27 positioned between the toe side auxiliary weight 26 and the heel side auxiliary weight 28. The insert 27 may be a weight insert similar to the toe and heel side auxiliary weights 26, 28, in which case the insert has a preferred mass of 2 to 35 grams. Alternatively or in addition to being a weight member, the insert 27 may include one or more indicators, such as a model or manufacturer's indication. The club head 1 further comprises a sole insert 105, and in the illustrated embodiment, two such sole inserts 105 are shown. These inserts 105 are preferably made of a lightweight material as described above. Such material is probably strong enough to withstand contact with the ground, for example, where the sole 12 occurs during normal use of the golf club. However, the arc shape of the sole 12 minimizes the risk of the insert 105 contacting the ground in the illustrated embodiment. By providing the sole insert 105, a large amount of mass is made available to provide an advantageous location in the club head, for example at the toe insert 26, intermediate insert 27 and / or heel insert 28. By disposing the insert 105 closer to the center of the sole 12, the mass is essentially moved closer to the outer portion of the club head 1 and the MOI of the club head is improved.

  12 is a cross-sectional view of the club head 1 of FIG. 11 taken along line 12-12. Here, it can be seen that the crown 13 is an insert coupled to the first body member 101 made of metal. The crown insert 13 is preferably made of a lightweight material, advantageously further offset for some other advantageous location without shifting the center of gravity of the club head downward and increasing the overall weight of the club head 1. Clear the mass. By providing holes for accommodating and positioning the crown insert 13, the skirt insert 35, the second body member insert 102 and the sole insert 105, the first body member 101 takes an overview of the frame. It should be noted that in certain embodiments of the invention, it is not necessary to provide all the inserts 13, 35, 102, 105. However, all of these may be provided. Since the first main body member 101 has a frame shape, the stress and distortion at the level of reduced stress and distortion (including stress and distortion generated by hitting the golf ball or the ground) generated during golf swing are reduced. A load support structure is obtained that does not adversely affect the lightweight portion of the club head 1 to be received. These club head portions, which may include the second body member 102, the crown 13, the skirt insert 35 and the sole insert 105, advantageously have a density lower than or equal to the metal material described above. Made of lightweight, high weight effect auxiliary materials such as low density metal alloys, plastics, composites, etc. so that the club head designer advantageously saves the “saved” weight or mass to the club head 1 Can be redistributed to other advantageous locations. These parts of the club head 1 may also be made thin, which promotes weight savings.

  The first body member 101 preferably has a mounting perimeter 18 for each insert (including the crown 13). These mounting perimeters 18 extend all the way along the edges of the respective openings. Preferably, each mounting perimeter 18 has steps that define two mounting surfaces 18a, 18b, which can further ensure a strong bond between the respective club head components. (Each mounting perimeter 18 in FIG. 12 has stepped portions that form two mounting surfaces 18a, 18b, but such mounting surfaces 18a, 18b are shown only in one place for clarity. Absent.)

  The opening provided in the club head 1 in which the inserts 13, 35, 102, 105 are accommodated preferably forms the entire club head shell in a known manner and then forms an opening in it. Can be formed. One preferable method for forming the opening is to partially remove the metal material of the first body member 101 using a laser. This method provides close tolerances. The mounting periphery 18 including the mounting surfaces 18a, 18b can be formed in various ways, for example, by machining the first body member 101 after laser cutting the opening in the club head 1.

  Instead of using the adhesive and mounting surfaces 18a, 18b, the lightweight inserts 13, 35, 102, 105 may be coupled to the club head 1 by simultaneous molding. By the simultaneous molding method, the insert can be held in place, and can be coupled to the club head 1 without the need for a mounting surface, an adhesive, a welding surface, or the like. By avoiding the use of these traditional bonding materials and structures, much mass is left to be positioned at an advantageous location within the club head 1. The club head designer is free to position the mass consumed by the mounting surface and mounting media (adhesive, epoxy, weld bead, mechanical fastener, etc.) as desired, eg, Advantageously position the center of gravity of the club head without increasing the overall weight, achieve the desired center of gravity placement, achieve the desired moment of inertia characteristics, increase the club head size and expand the club head sweet spot Can be done. This simultaneous molding process can be carried out in various ways. In one such method, the initial club head body is formed in a known manner. The initial club head body preferably has one or more cavities or recesses. For this, see for example the opening 30 in FIG. Thereafter, the initial club head body is placed in the mold. Next, a liquid material is poured into the mold to fill or at least contact the opening 30. Of course, the interior of the mold is shaped to give the desired shape to the finished club head. The initial club head and molding material are held in the mold for the required time, and these are subjected to the required thermal cycling if appropriate for the material used. In this way, the lightweight molding material is attached directly to the metal (or other) material of the club head body. Next, the club head is removed from the mold while the insert 35 is left as it is. As a variant, a ply of composite material or other lightweight material may be used instead of the liquid molding material. The molding time and molding temperature will vary depending on the material used, the thickness of the part to be formed and other factors known to those skilled in the art. The mold may have other parts for which the club head is desired by the designer, such as an inflatable bag. After the molding process is complete or before the molding process is complete, if desired, the bag can be deflated and removed through a small hole in the club head body that can be filled later or cover. As a modification, the mold may be partially formed of mold parts. These mold parts are later taken out from the club head through an opening provided in the face, for example, and the opening is opened. Later, it is covered with an insert. It should be noted that the molding material need not contact other ("larger") portions of the club head along the entire opening. In contrast, the contact relationship between the larger body and the smaller body is as strong as necessary to maintain the mechanical and structural health of the resulting golf club. You just need it. This limited contact area can be achieved, for example, by using an inflatable bag. The above-described features of the present invention, for example, the weights 23, 26, and 28 can also be used for the simultaneous molding sole 12.

  In addition to reducing the amount and number of materials required, co-molding also advantageously allows the use of materials not conventionally used by designers of golf club heads. For example, a translucent plastic material can be used as the lightweight insert material. In addition, the thickness of the molding material can be reduced. For example, the thickness of the simultaneous molding insert may be 1 to 1.2 mm. The molded insert may have a gradual thickness, for example by providing a smooth inner surface and a profiled outer surface or a profiled inner surface and a smooth outer surface. If a translucent material is used, the coloring and / or shading can be changed by changing the thickness of the insert.

  Each sole insert 105 preferably has a mass of 0.5 grams to 10 grams, more preferably 1 gram to 5 grams. The sole insert 305 and other inserts may be slightly beveled or stepped to provide room for excess adhesive. In one embodiment, the toe side sole insert 26 and the heel side sole insert 28 each have a preferred mass of 4 grams to 7 grams and the intermediate insert sole 27 has a preferred mass of 2 grams to 3 grams. In one embodiment, the thickness of the club head component is tapered so that the wall is thicker toward the face 11 and thinner toward the rear of the club head 1. Such a thick taper frees a mass for advantageous placement within the club head 1.

In another feature of the invention, the face 11 is made relatively wide. Providing a wide face 11 increases the size of the sweet spot of the club head, for example, and allows advantageous placement of weight members further away from the club head centerline, thereby improving club head playability and tolerance. . Golf regulations governing or governing bodies consider the club head heel to toe maximum distance of 5 inches (12.7 cm) and the club head sole to crown maximum distance of 2.8 inches (7. 112 cm). Thus, in the preferred embodiment shown in FIGS. 13 and 14, the face has a length FL of 5 inches (ie, a heel-toe measurement along the widest portion of the face 11) and 2.8. It has an inch height FH (ie, measured in the sole-crown direction along the highest portion of the face 11). These dimensions should be slightly smaller in order to comply with the rules. For example, the face length FL may be 4.5 to 5 inches (10.16 to 12.7 cm), more preferably 4.8 to 5 inches (12.19 to 12.7 cm). The thickness FH is 2.5 to 2.8 inches (6.35 to 7.112 cm), preferably 2.65 to 2.8 inches (6.731 to 7.112 cm). The dimension of the face 11 can also be expressed as an aspect ratio, which is the ratio of the face length FL to the face height FH. The aspect ratio regarding the face 11 is preferably 1.5 to 2, more preferably 1.7 to 1.9. Face dimensions can also be expressed as a measure of face surface area. Preferably, the face surface area is 40 cm ² or more, more preferably 45 cm ² or more, and even more preferably 50 cm ² or more. Preferred ranges for the face surface area is 40cm ² ~60cm ^2. In one preferred embodiment, the face surface area is about 54 cm ² .

  In addition to having a large face 11 (ie, wide at the heel-toe dimension (FL) and high at the sole-crown dimension (FH)), the club head 1 may be long in the face-rear dimension. . By providing a long club head body 10, the center of gravity of the club head is moved rearward from the face, thereby further improving the playability of the resulting golf club. This also allows for an advantageous placement of the weight far behind the face 11, and in one embodiment away from the club head centerline. Golf rules management or governing bodies believe that the distance from the heel to the toe of the club head must be greater than the distance from the face to the back. Thus, in the preferred embodiment, the club head depth HD is slightly smaller than the club face width. The preferred dimension for club head depth HD should be 4.5 to 5 inches, more preferably 4.8 to 5 inches. Preferably, the club head depth HD is ± 0.25 inches (6.35 mm) of the club head face length FL.

Preferably, the club head dimensions are the following elements:
The heel and toe (dimension FL) and the horizontal line between the vertical projection images of the outermost portion of the face and back (dimension HD) and the horizontal projection image of the outermost portion of the sole and crown (dimension FH) Measured with respect to the vertical line.

  COR is an important characteristic of golf clubs, in particular wood type golf clubs, for example the club head 1. COR is a measure of the efficiency of energy transfer between two mutually colliding objects, in this case, a golf club and a golf ball. Increasing energy transfer efficiency, ie, COR, increases initial ball speed and ball flight distance. During a golf shot, the club face and the golf ball are deformed upon impact. The club face can deform and then recover beyond the ball recovery. The ultimate goal of collision mechanics or physics is to limit the amount of deformation a ball can sustain. This is because energy is lost from the complete collision state due to heat generated in the ball. By allowing the striking face 11 to be deformed or bent as much as possible over a large proportion of the face 11, a high performance striking face 11 can be produced. As the club face deformation increases, the club head COR and the force exerted on the ball also increase. The wide club head 1 of the present invention preferably has a large COR, for example a COR of 0.8 or higher, more preferably 0.82 or higher. One preferred specific COR value is 0.83, which is the maximum limit allowed by a golf management or governing body.

Due to the increased width (heel-toe) of the club face 11 and the length (front-back) of the club head 1, the crown 13 has an increased surface area. The crown surface area, preferably, 100 cm ² or more, or about 100cm ² ~150cm ^2, one of the crown surface of illustration is about 107cm ^2. Further, the distance at the substantially center of the club head 1 from the crown-face intersection at the rear of the club head to the crown-skirt intersection is 4 inches (10.16 cm) or more. More preferably, this distance is 4.25 inches (10.95 cm) or more, more preferably 4.5 inches (11.43 cm) or more. This distance is perpendicular to the club face 11 and can be measured, for example, as a locus along the crown in a vertical plane passing through the center of gravity of the club face 11.

As described above, providing a large club head that is correctly balanced results in increased playability and tolerance of the club. The club head 1 preferably has a volume of 400 cm ³ or more. More preferably, the club head volume is 425 cm ³ or more. Even more preferably, the volume of the club head is 450 cm ³ or more. Management or governing bodies of the Rules of Golf, club head, believes that must not exceed 460cm ³ with a tolerance of 10cm ^3. Thus, the club head volume must meet the limits imposed by the governing or governing body.

  In order to position the center of gravity of the club head closer to the sole 12 and increase the club head MOI, thereby improving the tolerance and playability of the club head 1, the crown 13 of the club head 1 has a unique design. It is good to have. According to this aspect of the invention, at least 35% of the outer circumference of the club head is located below the center of gravity of the club head. As used herein, the term “perimeter” is defined as the arc length (arc length) of the outermost region of the crown 13. This feature is illustrated in FIGS. First, referring to FIG. 15, a rear view of the club head 1 (with the crown 13 omitted) is shown. A horizontal plane HP passing through the club head center of gravity CG is shown for reference purposes. As can be seen in FIG. 16 showing the heel side view of the club head of FIG. 15, the club head body 10 and the crown 13 (not shown) are inclined downward from the front portion to the rear portion of the club head 1. Yes. 17 is a plan view of the golf club head of FIG. 15 with the crown 13 in place. Due to the tilted crown profile, most of the crown 13 is located below the club head center of gravity CG. The outer periphery of the crown 13 is composed of two arc lengths A1 and A2. In FIG. 17, A1 indicated by a thick solid line indicates a portion of the outer periphery of the crown located on the center of gravity CG of the club head. A2 indicated by a thick broken line in FIG. 17 indicates a portion of the outer periphery of the crown located under the center of gravity CG of the club head. In the exemplary embodiment shown in FIG. 17, 35% of the crown periphery is located below the club head center of gravity CG. In another preferred embodiment, 40% of the crown circumference is located below the club head center of gravity CG. In yet another preferred embodiment, 45% of the crown circumference is located below the club head center of gravity CG. In another preferred embodiment, the rear height of the club head 1 is not more than 25% of the front height of the club head.

Structural or stiffening ribs 40 may be provided to absorb and transmit stresses and strains that occur during normal use of the resulting golf club. One advantageous location for such a rib 40 is along the central portion of the crown having a curved convex profile (as viewed from above the club head 1). Since the ribs 40 are responsible for most of the stresses and strains that occur during use of the golf club, other portions of the crown 13 can be designed to promote playability of the golf club. For example, the crown 13 may have concave dimples D ₁ and D ₂ . The dimples D ₁ and D ₂ lower the crown profile, thereby lowering the center of gravity of the club head. The preferred dimensions for dimple D ₁ displaced towards the club head toe are 2.9 to 3.5 inches (7.366 to 8.89 cm) for depth DD ₁ and 3 to 3.3 inches ( 7.62 to 8.382 cm) is more preferable, and the width DW ₁ is 2.2 to 2.6 inches (5.588 to 6.604 cm), and 2.3 to 2.5 inches (5.842). ~ 6.35 cm) is more preferred. The preferred dimensions for dimples D ₂ displaced toward the club head heel are 2.8-3.4 inches (7.112-8.636 cm) for depth DD ₂ , 3.1-3 .3 inches (7.874-8.382 cm is more preferred, with a width DW ₂ of 1.9-2.3 inches (4.826-5.842 cm) and 2-2.2 inches (5 As a variant, the dimples D ₁ and D ₂ may be the same, however, in order to achieve a well-balanced club head, the presence of the hosel 15 and In view of factors such as the club head par (standard number of hits) area, the dimples D ₁ and D ₂ should have different dimensions and shapes as described above. The determined center-of-gravity height CGH is less than 1 inch (2.54 cm) As a variant, the center-of-gravity height CGH is 0.7 to 1.1 inches (1.778 to 2.54 cm), More preferably, it is 0.8 to 0.9 inches (2.032 to 2.286 cm) These technical ideas are shown in Fig. 18, and Fig. 18 is a front view of the golf club head. And includes three cross-sections: cross-section AA through the central portion of the club head, cross-section BB through the toe portion of the club head, and cross-section CC through the heel portion of the club head. ing.

To further remove weight from the upper portion of the club head, the crown or portion of the crown may be comprised of, for example, the lightweight material described with respect to the second body member 102 described above. The entire crown 13 may be made of such a lightweight material, or only some of the crown, for example, the dimples D ₁ and / or D ₂ may be made of a lightweight material. It should be noted that the term “lightweight material” includes a thin portion of metal or other typically heavy material. The curved profile of the crown 13 described above helps to maintain the structural integrity of the crown 13. Also, the above-described club head attributes provide the club head 1 with an advantageous MOI. Preferably, the club head 1 has a MOI of 260 kg · mm ² or more around a horizontal axis passing through the center of gravity of the club head and a MOI of 420 kg · mm ² or more around a vertical axis passing through the center of gravity of the club head. More preferably, these MOI values are 270 kg · mm ² and 450 kg · mm ² , respectively. More preferably, the MOI values are 280 kg · mm ² and 470 kg · mm ² , respectively. The upper limit of the MOI, respectively, and even better at 350 kg · mm ² and 550 kg · mm ^2.

  In the textual specification, "a", "an" and "the" and similar characters used in the context of the description of the present invention shall be singular and plural unless otherwise indicated or clearly contradicted by context. Should be understood to include both. The range of values described herein serves only as a short way to individually refer to each of the separate values belonging to this range unless otherwise indicated, and each of the separate values is as if it were Each is incorporated herein as if it had been individually described herein.

  In the present specification, expressions representing directions, such as rear (rear), front (front), and lower, relate to the club head when it is on the ground at the address position. For this, see, for example, FIG. The terminology indicating the direction is described in order to facilitate understanding of the technical idea of the present invention disclosed in this specification, and should not be construed as limiting the present invention.

  While preferred embodiments of the present invention have been described above, it is to be understood that these embodiments are provided by way of example only and are not intended to limit the invention. Those skilled in the art will envision various modifications in the form and details of these embodiments without departing from the spirit and scope of the invention. For example, although two body members have been described above, the present invention can be embodied in a club head having three or more body members. In addition, the present invention can be embodied in any type of club in addition to the wood type club shown. Thus, the present invention should not be limited by the above-described exemplary embodiments, but should be defined only by the scope of the present invention as set forth in the claims and the equivalents thereof. Further, although certain advantages of the invention have been described herein, it should be understood that not all such advantages can be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will appreciate that the present invention achieves one advantage or combination of advantages taught herein without necessarily achieving the other advantages taught or suggested herein. It will be appreciated that it can be embodied or implemented in a way that is optimized or optimized.

It is a figure which shows the golf club head of this invention. It is a figure which shows the main body member of the golf club head of FIG. It is a figure which shows the 2nd club head of this invention. FIG. 4 is a bottom view of the golf club head of FIG. 3. It is a bottom side perspective view of the club head of the present invention. FIG. 6 is a rear view of the club head of FIG. 5. FIG. 6 is a heel side view of the club head of FIG. 5. FIG. 6 is a schematic bottom view of the club head of FIG. 5. FIG. 6 is a cross-sectional front view of the club head of FIG. 5. It is a bottom view of the golf club head of the present invention. It is a bottom view of the golf club head of the present invention. FIG. 12 is a cross-sectional view of the golf club head of FIG. 11 taken along line 12-12. 1 is a front view of a golf club head of the present invention. FIG. 14 is a plan view of the golf club head of FIG. 13. It is a rear view of the golf club head of the present invention in the state where a crown is omitted. FIG. 16 is a heel side view of the golf club head of FIG. 15. FIG. 16 is a plan view of the golf club head of FIG. 15 with a crown in place. 1 is a front view of a golf club head of the present invention and includes three cross-sectional views of the golf club head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Golf club head 10 Main body 11 Hitting face 12 Sole 13 Crown 14 Skirt 15 Hosel 16 Inner volume part 20 Recessed part 22 Convex bulge 23 Insert 26, 28 Auxiliary weight 101 1st main body member 102 2nd main body member

Claims (58)

A golf club head,
A first body portion made of a metallic material and having an opening formed therein;
With the insert positioned in the opening and joined to the first body portion by simultaneous molding without using an adhesive or weld,
Golf club head.   The golf club head of claim 1, wherein the insert is made of a lightweight material.   3. The golf club head of claim 2, wherein the lightweight material includes one or more of a composite, polypropylene, kevlar, magnesium, thermoplastic, plastic, polymer, and low density metal alloy.   The golf club head of claim 1, wherein the first body portion is formed with a second opening, and the golf club head further comprises a second insert housed in the second opening. .   The second insert is made of a lightweight material including one or more of composites, polypropylene, kevlar, magnesium, thermoplastics, plastics, polymers, and low density metal alloys. 4. The golf club head according to 4.   The golf club head has a sole, and further includes a first weight insert positioned on a toe side of the sole, and a second weight insert positioned on a heel side of the sole. The golf club head of claim 1, wherein the second weight inserts each have a mass between 2 grams and 35 grams. The center point on the sole defines the lowest point of the golf club head;
The center of gravity of each of the first and second weight inserts is located at least 0.5 inches (12.7 mm) behind the center point, and for the first weight insert from the center point. At least 0.75 inches (19.05 mm) toward the toe of the golf club head, and at least 0.75 inches (19.05 mm) from the center point toward the heel of the golf club head for the second weight insert. The golf club head of claim 6, wherein the golf club head is located at a maximum of 0.25 inches (6.35 mm) above the center point. The golf club head of claim 1, wherein the golf club head has a face having a surface area greater than 40 cm ² . The golf club head of claim 1, wherein the golf club head has a crown with a surface area greater than 100 cm ² . The golf club head has a striking face and a sole,
The striking face has a surface area greater than 40 cm ² ,
The golf club head of claim 1, wherein the golf club head has a center of gravity located a distance of about 1 inch or less from the sole. The golf club head has a striking face having a depth measured in a heel-toe direction and the golf club head has a depth measured in a face-rear direction;
The depth is 4.5-5 inches (11.43-12.70 cm);
The golf club head of claim 1, wherein the width is 4.5 to 5 inches (11.43 to 12.70 cm).   The golf club head of claim 11, wherein the depth is within ± 0.25 inches (6.35 mm) of the width.   The golf club head of claim 1, wherein the golf club head has a striking face having a height of 2.5 to 2.8 inches (6.35 to 7.11 cm) measured in the sole-crown direction.   The golf club head of claim 1, wherein the golf club head has a striking face with an aspect ratio greater than 1.5.   The golf club head according to claim 1, wherein the golf club head has a center of gravity, a crown having an outer periphery, and a sole, and at least 35% of the outer periphery is located on a sole side of the center of gravity. A method of making a golf club head comprising:
Prepare an initial club head body with an opening,
Positioning the initial club head body in a mold;
Inserting a molding material into the mold adjacent to the opening;
Molding the molding material,
Removing the golf club head from the mold,
Method.   The method of claim 16, further comprising inserting a bag into the mold with the bag in the initial club head body.   The method of claim 16, wherein providing the initial club head body includes providing an initial club head body in which the opening is located within a skirt region of the initial club head.   The method of claim 16, wherein providing the initial club head body includes providing an initial club head body in which the opening is located within a crown region of the initial club head.   The method of claim 16, wherein the inserting step includes inserting a fluid molding material into the mold.   21. The method of claim 20, wherein the inserting step further comprises mixing a plurality of types of fluid materials and inserting the mixed fluid into the mold.   The method of claim 16, wherein the inserting step includes positioning one or more plies of composite material in the mold.   The method of claim 16, wherein providing the initial club head body includes removing material from the precursor club head body to form the initial club head body. A golf club head comprising a body having a striking face, a sole, a crown, a heel, and a toe, wherein the striking face has a width measured in a heel-toe direction and a height measured in a sole-crown direction. Have
The striking face has a surface area greater than 40 cm ² ;
A golf club head, wherein an aspect ratio determined by dividing the width by the height is greater than 1.5. The golf club head of claim 24, wherein the surface area is greater than 45 cm ² . The golf club head of claim 24, wherein the surface area is greater than 50 cm ² .   The golf club head of claim 24, wherein the aspect ratio is greater than 1.7. The golf club head of claim 24, wherein the crown has a surface area greater than 100 cm ² .   25. At least a portion of the crown is an insert made of a material selected from the group consisting of composites, polypropylene, kevlar, magnesium, thermoplastics, plastics, polymers, and low density metal alloys. Golf club head.   25. At least a portion of the sole is an insert made of a material selected from the group consisting of composites, polypropylene, kevlar, magnesium, thermoplastics, plastics, polymers, and low density metal alloys. Golf club head.   The first weight insert further positioned on the toe side of the sole and the second weight insert positioned on the heel side of the sole further includes two first and second weight inserts, respectively. 25. A golf club head according to claim 24, having a mass between grams and 35 grams. The center point on the sole defines the lowest point of the golf club head;
The center of gravity of each of the first and second weight inserts is located at least 0.5 inches (12.7 mm) behind the center point, and for the first weight insert from the center point. At least 0.75 inches (19.05 mm) toward the toe of the golf club head, and at least 0.75 inches (19.05 mm) from the center point toward the heel of the golf club head for the second weight insert. 32. The golf club head of claim 31, wherein the golf club head is located at a maximum of 0.25 inches (6.35 mm) above the center point. A golf club head,
Having a body with a striking face, a sole and a crown;
The striking face has a surface area greater than 40 cm ² and the golf club head has a center of gravity located a distance of no more than about 1 inch (2.54 cm) from the sole;
Golf club head. The surface area is greater than 45cm ^2, the golf club head of claim 33.   34. A golf club head according to claim 33, wherein an aspect ratio of the hitting face is greater than 1.5. 34. A golf club head according to claim 33, wherein the golf club head has a volume greater than 400 cm < ³ >. 37. A golf club head according to claim 36, wherein the volume is greater than 425 cm < ³ >. Surface area of the crown is greater than 100 cm ^2, the golf club head of claim 33.   34. A golf club head according to claim 33, wherein a distance measured substantially from the crown-face intersection point to the trailing edge of the crown at the center of the golf club head is greater than 4 inches (10.16 cm).   40. A golf club head according to claim 39, wherein the distance is greater than 4.25 inches. A golf club head,
A striking face, a crown, a sole, a heel, a toe, and a rear body; the striking face having a width measured in a heel-toe direction; and the golf club head comprising a face -Having a depth measured in the rear direction;
The striking face has a surface area greater than 40 cm ² ;
The depth is 4.5-5 inches (11.43-12.70 cm),
Golf club head.   42. A golf club head according to claim 41, wherein the depth is within ± 0.25 inches (6.35 mm) of the width. The depth is 4.5-5 inches (11.43-12.70 cm);
42. A golf club head according to claim 41, wherein the width is 4.5 to 5 inches (11.43 to 12.70 cm). The surface area is greater than 45cm ^2, the golf club head of claim 41, wherein.   42. A golf club head according to claim 41, wherein the striking face has a height of 2.5 to 2.8 inches (6.35 to 7.11 cm) measured in the sole-crown direction. Surface area of the crown is greater than 100 cm ^2, the golf club head of claim 41, wherein. A golf club head with a center of gravity,
A main body having a striking face, a sole and a crown, the crown having an outer periphery;
At least 35% of the outer periphery is located on the sole side of the center of gravity,
Golf club head.   48. A golf club head according to claim 47, wherein at least 40% of the outer periphery is located on a sole side of the center of gravity.   48. The golf club head of claim 47, wherein the crown has stiffening ribs and at least one recessed area.   50. A golf club head according to claim 49, wherein when viewed from above the crown, the stiffening rib has a convex profile and the recessed area has a concave profile.   The crown has two recessed areas, each of which is 2.8 to 3.5 inches (7.11 to 8.89 cm) deep and 1.9 to 2.6 inches (4. 50. A golf club head according to claim 49, having a width of 83 to 6.60 cm). The first of the recessed areas has a depth of 2.9-3.5 inches (7.37-8.89 cm) and 2.2-2.6 inches (5.59-6.60 cm). )
The second of the recessed areas has a depth of 2.8 to 3.4 inches (7.11 to 8.64 cm) and 1.9 to 2.3 inches (4.83 to 5.84 cm). 52. The golf club head of claim 51, having a width of   52. A golf club head according to claim 51, wherein each of the recessed areas is of the same size.   50. A golf club head according to claim 49, wherein the stiffening rib is located on a crown side of the center of gravity, and the recessed area is located on a sole side of the center of gravity. The striking face has a surface area greater than 40 cm ^2, the golf club head of claim 47, wherein.   48. The golf club head of claim 47, wherein the golf club head has a front height and a rear height that is 25% or less of the front height. A golf club with a center of gravity,
Having a body with a striking face;
The striking face has a surface area greater than 40 cm ² ;
The golf club head has a moment of inertia greater than 260 kg · mm ² around a vertical axis passing through the center of gravity. 58. A golf club head according to claim 57, wherein the golf club head has a moment of inertia greater than 420 kg · mm ² about a horizontal axis passing through the center of gravity.