JP2006110348A - Forged iron-type golf club - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maximize the size of a club head while keeping the weight of the whole golf club desirable and useful. <P>SOLUTION: This forged cavity back club and oversize club are improved in durability and workability. This forged club includes a thin durable hitting face having durability, and has a relatively large cavity volume. The club has a large rotational inertia moment to minimize the carry and accuracy penalties associated with off-center hits. A long iron club having the hitting face about 0.100 thick inch may be achieved. Further, after the stainless steel is forged, it is annealed to realize desired hardness and extensibility. Further, this invention discloses an interchangeable pin suitable for use in the manufacture of any of a set of iron-tye clubs without re-tooling. The pin is sized and configured to fit within a through bore, and flexible adhesive such as epoxy is placed within the gaps to provide a vibration damping effect. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates generally to golf clubs, and more specifically to iron clubs.

  The striking face area and weight of individual golf club heads in a club set typically increases gradually from long irons to short irons. Thus, the hit face area of a long iron club head is smaller than that of a short iron, making it more difficult for an average golfer to hit consistently well. This is due to a small sweet spot with at least a small striking face in a normal club head.

  A number of golf clubs with so-called cavity-structured heads and increased surrounding weight are available to allow the average golfer to consistently hit the club head sweet spot. Another recent trend is to increase the overall club head size, especially in long irons. Each of these characteristics increases the size of the sweet spot, and as a result, even if the ball hits slightly off the center, it hits the sweet spot and the ball flies farther and straighter. A challenge for golf club designers when trying to maximize the size of a golf club head is to keep the overall weight of the golf club desirable and beneficial. For example, if a 3 iron club head is made heavy and heavy, it will be difficult for the average golfer to swing the club properly.

  Generally, the center of gravity of these clubs is moved to the bottom and back of the club head. This allows the average golfer to hit the ball faster into the air and hit the ball farther. Furthermore, the moment of inertia of the club head is increased, and even if it is hit away from the center, it is not penalized so much in terms of distance and accuracy. Material or mass is moved from one area of the club head to another in order to move the weight downward and rearward without increasing the overall weight of the club head. To take material from the club head face, one solution has been to produce a thin face. Examples of this type of configuration can be found in US Pat.

  Iron clubs (including wedge clubs) are manufactured by investment casting, machining or forging. Forged club heads are eagerly awaited by skilled amateur golfers and professional golfers for their outstanding competitive characteristics. On the other hand, forgeable alloys are malleable and typically have low yield strength. Because of this drawback, the forged club face cannot be thinned.

  Forged iron clubs available for purchase are typically muscle backs (thick reinforced) such as the Tietist ™ Forged 670, 680, 690 series, Mizuno MP-33 ™ iron and Kenneth Smith's RoyalSignet ™ club. It is. The RoyalSignet ™ muscle back club concentrates the club weight near the central sweet spot and reduces the moment of inertia. Forged cavity back iron clubs are also available as medium sized clubs with relatively thin striking faces, such as Titleist (TM) 690-CB, Hogan Apex Edge Pro or Royal Signet (TM) Titanium. is there. The Hogan Apex Edge Pro Iron is a single piece club forged from carbon steel, while the Hogan CFT club has a stamped face attached to the cast body. The Royal Sign Titanium club is reinforced with a cast stainless steel club using a full face insert made of forged titanium.

Accordingly, it is still desirable to improve forged iron club heads.
US Pat. No. 4,928,972 US Pat. No. 6,045,456

  The present invention is directed to a golf club head having a hosel and a hole extending from the hosel toward the club head sole. The density of the pins arranged in the holes is smaller than the density of the club head.

  The present invention is also directed to a golf club head having a hole extending from the hosel toward the sole of the club head. At least two attenuation regions are set in the hole.

  The present invention is also directed to a golf club head having a hole extending through the sole from the top of the hosel through the heel of the club head, and a long pin secured to the interior of the hole using an adhesive. . The pin has a main body having a main body outer diameter, a base having a base outer diameter, and an extension portion of an extension outer meter. The base outer diameter is smaller than the main body outer diameter and the extension outer diameter is smaller than the main body outer diameter. The geometric center of the extension is offset from the geometric center of the body. Further, an upper gap is formed between the pin extension and the inner wall of the hole, and a lower gap is formed between the base of the pin and the inner wall of the hole. Place the pin in the hole. The pin and hole are preferably keyed so that the pin is fixed in place when inserted. The upper gap and the lower gap are filled with adhesive.

  The present invention also includes an iron type including a hosel, a front, and a back, the back including a cavity defined by a surrounding member, and the front including a striking zone provided at a position facing the cavity. It is aimed at golf clubs. The club head is forged from a malleable metal, such as stainless steel, more preferably annealed. The forged club head further has a hole that passes from the top of the hosel to the sole through the heel of the club head, and a long pin that is secured to the hole using an adhesive. The pin has a main body having a main body outer diameter, a base having a base outer diameter, and an extension having an extension outer diameter. The base outer diameter is smaller than the main body outer diameter, and the extension outer diameter is smaller than the main body outer diameter. The geometric center of the extension is offset from the geometric center of the body. Further, an upper gap is formed between the pin extension and the inner wall of the hole, and a lower gap is formed between the base of the pin and the inner wall of the hole. Place the pin in the hole. The upper gap and the lower gap are filled with adhesive.

  The present invention is also directed to a golf club head for an iron type golf club having a striking face, a sole and a hosel. A hole in the heel extends from the hosel to the sole and pins with a density less than the rest of the club head are placed in the hole. The pins redistribute the mass of the club head so that the distance from the ground plane to the center of gravity as measured when the club head is placed in the address position is closer to the ground plane than the center of gravity of a similar club head without holes It has become.

  A club head 10 according to an embodiment of the present invention is shown in FIGS. FIG. 16 shows details of the cavity configuration of this embodiment. The club head 10 has a front 12, a back 14, a top 16, a sole 18, a heel 20, a toe 22, and a hosel 24. Club head 10 is a single piece forging. That is, it is forged from a single ingot and does not include a face insert. Alternatively, it consists of a stainless steel body and a stainless steel insert. The body is forged and the insert is forged or stamped. A shaft (not shown) is connected to the club head 10 in the hosel 24, and a grip (not shown) is provided at the protruding end of the shaft. The grooves on the front 12 are omitted in the figure for clarity. The front 12 has a striking zone 26 that is preferably defined by a rear cavity region and is located opposite the upper portion 28 and the reinforcing portion 30 as best shown in FIGS. Yes. The club head 10 is a “cavity back” club. That is, a substantial portion of the club head mass is located on the backside around the periphery 32 of the club head. As described further below, the cavity back design causes the club to have a greater rotational moment of inertia, preventing the club head's rotational tendency caused by off-center strikes. Within the perimeter 32, the upper portion 28 is the thinnest member of the striking zone 26. The minimum thickness of the front 12 is in the upper portion 28. The reinforcing portion 30 is thicker than the upper portion 28 and structurally supports the striking face. The upper portion 28 and the reinforced portion 30 together are similar to a traditional “muscle back” forged club. Club head 10 also has a pronounced appearance that includes a muscle back in the cavity. The reinforced portion 30 may be provided with a depression 34 to provide a more specific structure.

  In addition, the mass distribution within the perimeter 32 is biased toward the sole 18. As a result, the center of gravity of the club head 10 is behind and below the geometric center of the face. The geometric center can be defined as the intersection of the vertical centerline and the horizontal centerline of the front 12. Alternatively, it can be defined as the midpoint of the groove region. As best shown in FIGS. 3, 4 and 7, the thickness of the top of the perimeter 32 is substantially less than the thickness of the bottom of the perimeter 32. When the center of gravity is below and behind the geometric center of the striking face, the club launches the golf ball in a higher trajectory and achieves a longer flight distance.

  Another embodiment of the present invention is shown in FIG. FIG. 17 shows the details of the cavity configuration of this embodiment. This embodiment is substantially similar to the embodiment of FIGS. However, this club head is an “oversize” club head. As used herein, an oversized club head includes, but is not limited to, a club head that is larger in size than a conventional club head, a club head having a “sweet spot” larger than a conventional club head, and a relative A cavity back club head having a large cavity volume. The cavity volume is surrounded by the back surface of the striking zone 26, that is, the combined surface of the portions 28 and 30, the inner surface of the peripheral weight 32, and the virtual plane or aspect formed by the outer edge 36 of the periphery 32. It is defined as the volume in the 3D shape. The outer edge 36 is best represented in FIG. The club head of FIG. 8 is an oversized version of the club head of FIGS. 1-7 based on the relative differences in the cavity volumes. This difference in cavity volume is best illustrated by the difference in thickness 38 and circumference 32 of FIGS. FIG. 15 is a sectional view of this club, showing the thickness t1 of the upper portion 28 and the thickness t2 of the reinforcing portion 30. FIG.

Table 1 below shows preferred cavity volumes for the clubs of this invention.
FIG. 11 plots how the cavity volume of the club head 10 of the above two embodiments changes according to the loft angle of the club head. As shown in FIGS. 11, 13, and 14, curve A shows the characteristics of the non-oversized club of the present invention, and curve B shows the characteristics of the oversized club of the present invention. FIG. 11 shows that the cavity volume of the oversized club is always greater than the cavity volume of the other clubs. Further, for clubs with loft angles (LA) less than about 32 °, the cavity volume is greater than about 10 cm ³ (cc). The cavity volume for all clubs is at least about 8 cc. For oversized clubs, the cavity volume is at least about 12 cc for all clubs, preferably greater than about 13 cc. Further, as will be discussed below, the larger cavity volume of the oversized club of the present invention can provide the desired large rotational moment of inertia.

  According to one aspect of the invention, malleable stainless steel is a preferred material for the forging process. Typically, carbon steel has been used for forging because of its softness. However, since carbon steel rusts, it needs to be chrome plated for protection. Since chrome plating is not ductile, it tends to crack. This limits the lie, loft, and flexibility. Chromium plating has also been a constraint for golf club manufacturers to polish the finished head to adapt the weight, shape and / or sole structure. This is because thin chrome plating is peeled off.

  Preferred stainless steel has a yield strength of less than about 90,000 and an elongation greater than about 13%. More preferably, the material has a yield strength of less than about 85,000 and an ultimate elongation of about 15% to about 21%. A preferred stainless steel also has a Rockwell hardness of about 25 HRC (Hardness Rockwell C scale). Suitable stainless steels include 410 stainless steel, the chemical composition of which is 86.98% Fe, 11.3% Cr, 0.723% Mn, 0.366% Si, 0.297% Ni, 0.11 % C, 0.034% P, 0.033% Cu, 0.03% Mo, 0.02% V, 0.017% S, 0.01% Al. Another suitable stainless steel is 403 stainless steel, which has a chemical composition of 86% Fe, 12.3% Cr, up to 1% Mn, up to 0.5% Si, up to 0.15% C, A maximum of 0.04% P and a maximum of 0.03% S.

  Forged club heads made from 410 stainless steel have a hardness in the range of about 14.2 to about 17.3 HRC. The forging process may include multiple forging steps, with each forging step followed by other steps such as polishing, sand blasting, removing flushing, and trimming. For example, after performing the preceding forging step, polishing and / or sandblasting is performed, and then rough forging step is performed a plurality of times. After further polishing and sand blasting, the grooves are cut or stamped and a precision forging step (s) is performed to finish the forging process.

  According to another aspect of the invention, the forged club head is further annealed (heated) to reduce its hardness to less than about 40 HRC, preferably less than about 90 HRB, more preferably less than about 80 HRB. In one embodiment, the club is soft to facilitate custom processing and has a hardness of less than about 90 HRB. In one example, the forged club head is heated to about 1050 ° C. for about 90 minutes and then about 650 ° C. for about 120 minutes.

The forged club head can have any desired hardness by post-forging heat treatment. Advantageously, the problem that the club head is too hard to easily customize the loft or lie is solved by increasing the hardness. The hardness of the annealed forged metal is advantageously in the same range as the hardness of cast materials such as cast 431 stainless steel or cast 8620 carbon steel used in high end cast clubs such as Titleist ™ DCI iron. is there. The physical properties of these materials are shown below.
Therefore, in the present invention, the problem of the thick striking face can be solved by selecting a forged stainless steel having ductility and malleability that is better than a chrome-plated soft carbon steel and annealing the forged club head.

  Another advantage realized by the annealing step is that the crystalline structure of the forging material is improved. As shown in FIGS. 9 (a) and 9 (b), the forged club head has a relatively small grain size, but the grain size is significantly improved as shown in FIGS. 10 (a) and 10 (b). Large grain size microstructured metals have greater ductility. Preferably, the grain size is greater than about 10 μm to about 50 μm. As shown in the above table, the elongation of the annealed forging 410SS approaches the elongation of the casting 431SS. The chemical composition of 431 stainless steel is 82% Fe, 15-17% Cr, 1.25-2.5% Ni, up to 1% Mn, up to 1% Si, up to 0.2% C, up to 0 0.04% P, maximum 0.03% S.

  Furthermore, the bending workability of the forged annealing 410SS exceeds 17-4 PH SS. This is another metal that is widely used in iron clubs and similar to casting 431SS. Other suitable materials include, but are not limited to, forging 403SS, 431SS, 416SS, 303SS, 304SS, 304SS, 329SS, 316SS, 259SS, Nitronic 40, Nitronic 50, and Nitronic 60. A suitable stainless steel has at least 10% Cr. The forging and annealing processes can be adjusted to easily obtain the desired hardness, tensile strength and ductility according to the process described above.

  The minimum thickness of the hitting zone of the iron club of the present invention can be in the same range as the thickness of the cast iron club. In one embodiment, the striking zone 26 thickness can be less than about 0.100 inch. The inventors of the present invention have produced clubs having a striking zone about 0.098 inches thick for long irons, ie, Nos. 1, 2 and 3 irons. In other embodiments, specifically two-piece embodiments, i.e., those comprising a forged body and a forged or stamped insert, it is 0.060 inches thick.

The minimum thickness of the striking zone 26 can be characterized in terms of the club aspect ratio, i.e., the ratio of the striking zone 26 to its minimum thickness. Referring to FIG. 2, the area of the striking zone 26 in the front 12 is evaluated as the product of the length L of the striking zone 26 and the average height of the striking zone 26. Two representative heights H1 and H2 are shown. In other words, the striking zone 26 is the corresponding area at the front opposite the upper part 28 of the cavity back and the reinforcing part 30. The minimum thickness t1 is measured in the upper portion 28. The defined aspect ratio covers the striking zone 26 and the area of the portion 28 comprises about 50% to about 90% of the total area of the striking zone 26, more preferably about 60% to about 80%. . The thickness of the reinforced portion 30 is about 1.2 to about 3 times the thickness of the upper portion 28. The relative thickness of the upper portion 28 (t1) and the reinforcing portion 30 (t2) is shown in FIG.
As used herein, club numbers 1-9, pitching wedge (PW), and sand wedge (SW) are widely accepted descriptions in the golf club industry. Iron club sets typically range from 3 irons to PW, or 5 irons to PW, and can include other clubs in a custom order. It should also be noted that manufacturers can manufacture different clubs in the same set in different manners, such as a cavity back / muscle back set. The iron club may also include a gap wedge. These clubs may also be defined by other characteristics, such as but not limited to loft angles. The area of the striking zone 26 is shown in FIG. 12, the minimum thickness of the upper portion 28 is shown in FIG. 13, and the aspect ratio between the area of the striking zone 26 and the minimum thickness is shown in FIG. 12 and 14, curve A shows the area and aspect ratio of the normal club hit zone 26 of the present invention, and curve B shows the area and aspect ratio of the hit club 26 of the oversized club of the present invention.

FIG. 12 shows the large striking zone of the normal and oversized clubs of the present invention due to the large cavity area in addition to the large face area. FIG. 13 shows a thin single piece stainless steel forged face with a minimum thickness of about 0.200 inches or less, more preferably less than about 0.130 inches, at an LA of less than about 35 °. FIG. 14 shows the aspect ratio (AR) of the club of the present invention and beneficially shows having a large striking area and a thin face. AR is AR> = ((1 / 4.5) × LA) +25
It is represented by In FIG. 14, a line segment C is a straight line representing this expression.

  The rotational moment of inertia (“inertia”) of golf clubs is well known in the art and has been discussed in many references, including US Pat. No. 4,420,156. Refer to this for details. If the inertia is too small, there is a tendency to rotate excessively by hitting off the center. As the inertia increases, the rotational mass increases, and even if there is a strike deviated from the center, the rotation is reduced. Inertia is measured about a vertical axis (Iyy) through the center of gravity of the club head, as shown in FIG. 1, and is measured on a horizontal axis (Ixx) about the center of gravity (CG) of the club head. The tendency of the club head to rotate about the y-axis through the CG represents the amount of rotation caused by a strike off the y-axis. Similarly, the tendency of the club head to rotate about the x-axis through the CG represents the amount of rotation caused by the strike off the x-axis through the CG. If Ixx and Iyy are large, the tendency to rotate can be suppressed, and a hit off the center can be more tolerated.

  Inertia is also measured around the shaft axis (Isa) as shown in FIG. First, the face is set at the address position, the face is squeezed, and the loft and lie angles are set before the measurement. Any golf ball strike tends to rotate the club head about the shaft axis. When the impact deviates from the center to the toe side, there is a tendency to rotate more around the shaft axis. When the impact shifts from the center to the heel side, the tendency to rotate around the shaft axis decreases. When Isa is large, the tendency to rotate becomes small, and it becomes easy to control the hitting face. Large Ixx, Iyy and Isa have been realized in high end cast iron clubs. According to the present invention, this can be realized with a high-end forged iron club.

As described above, the club head striking zone thickness can be about 0.100 inch with a 2 iron and about 0.150 inch with a sand wedge (SW). The weight moves around the club head, the sole can be about 0.540 inches to about 0.780 inches thick, and the top is about 0.180 inches to about 0.380 inches, more preferably about The thickness can be from 0.240 inches to about 0.320 inches. The specific inertia of the club of the present invention is calculated using computer aided design (CAD) as follows and compared with the inertia of a conventional forged muscle back (no ambient weighting). A comparative example is a Titleist ™ 670 forged iron.
As mentioned above, the relatively large cavity volume of the oversized club of the present invention provides a large moment of inertia, especially for Isa and Iyy.

  The position of the center of gravity is also listed above. GC-y is the distance from the ground when the club is placed at the address position. CG-x is the distance from the center of the face when similarly arranged. CG-sa is the distance from the shaft axis when similarly arranged. The center of gravity is located below and behind the geometric center of the hitting face. The geometric center can be defined as the midpoint of the region of the groove or score line, as described above. It is very clear that the moment of inertia of this invention is greater than the moment of inertia of the comparative club.

  In order to maintain the desired overall weight of the club head 10 while adding material to thicken the perimeter 32, the material may be removed from any area of the club head 10. FIGS. 16-20 illustrate another embodiment of the present invention in which material is removed from the heel 20 and redistributed elsewhere. In this embodiment, the club head 10 includes a hosel 24 into which a club shaft 42 is inserted. 16-18, the material is removed from the club head 10 to form a hole 44 that extends through the heel 20 and the pin 40 is inserted into the hole 44. The hole 44 preferably extends from the top of the hosel 24 to communicate with the sole 18. Preferably, the club head 10 is formed by drilling after being manufactured by forging according to the above-described embodiment.

  The bore 44 has a first diameter main channel 52 and a second diameter single upper channel 54, the geometric center of the upper channel 54 being offset from the geometric center of the main channel 52. Both main channel 52 and upper channel 54 are preferably cylindrical, i.e. their cross-sectional shapes are circular. However, other shapes such as ellipses and polygons are also suitable. The diameter of the upper channel 54 is preferably much smaller than the diameter of the main channel 52. For illustrative purposes only, in one embodiment, the diameter of the upper channel 54 is preferably in the range of 1 mm to 5 mm and the diameter of the main channel 52 is in the range of 3 mm to 10 mm. More preferably, the upper channel 54 has a diameter of 2.5 mm and the main channel 52 has a diameter of 5 mm. The transition from the large diameter of the main channel 52 to the small diameter of the upper channel 54 is preferably an abrupt step, but may be a gradually changing taper or any similar structure.

  The pin 40 is inserted into the hole 44. The pin 40 occupies most of the gap formed by the hole 44. Pin 40 preferably extends from sole 18 to a position in hole 44 below the lower end of shaft 42. The bottom surface 51 of the pin 40 is preferably flush with the outer surface of the sole 18 as shown in FIG. Alternatively, if the bottom surface 51 is not flush with the outer surface of the sole 18, that is, if the pin 40 does not extend to the outer surface of the sole 18, it is made of a metal such as stainless steel or a polymer such as urethane. A cap is fixed to form a flat surface.

  Pin 40 is preferably solid and generally cylindrical and is made from a lightweight material such as magnesium, aluminum, other lightweight metals, or a low density, high strength polymer. That is, the pins 40 are made of a material that is less dense than the material of the rest of the club head so that the weight of the club head 10 around the hosel 24 is reduced. Alternatively, more material may be used, such as steel or titanium, making the pin 40 hollow. The pin 40 is preferably manufactured by molding, but may be manufactured by any method known in this field, for example, by forging or machining. More preferably, the pin 40 is made of a polymeric material such as STYLAC ™ ABC available from Asahi Kasei Chemical Co., Japan.

  As shown in FIGS. 19 and 20, the geometry of the pin 40 corresponds to the geometry of the hole 44. The pin 40 preferably includes three cylindrical portions with different cross-sectional diameters: a pin extension 46, a pin body 48, and a pin base 50. The outer diameter of the pin body 48 is approximately equal to the diameter of the main channel 52 of the hole 44 and the pin 40 is tightly supported within the hole 44.

  The pin extension 46 is preferably integral with the pin body 48 and extends from the top side of the pin body 48. The outer diameter of the pin extension 46 is preferably significantly smaller than the outer diameter of the pin body 48. For example, in one embodiment, the outer diameter of the pin extension 46 is approximately equal to the diameter of the upper channel 54 of the hole 44. For illustrative purposes, in one embodiment, the pin extension 46 has a diameter in the range of 1 mm to 5 mm and the pin body 48 has a diameter in the range of 3 mm to 10 mm. More preferably, the pin extension 46 has a diameter of 2.3 mm and the pin body 48 has a diameter of 4.8 mm. The transition from the large diameter of the pin body 48 to the small diameter of the pin extension 46 is preferably an abrupt step, but may be a gradually changing taper or any similar structure.

  The pin extension 46 is preferably shorter than the pin body 48 in terms of its length. The length of the pin extension 46 is preferably sufficient to leave an upper gap between the upper side of the pin body 48 and the upper shoulder 55 of the hole 44. The upper gap 56 provides a vertical transition of the pin 40 during manufacture so that the bottom surface 51 is aligned with the sole 18. Thus, the pins can be used in any iron club set product without reworking the pins 40 to fit clubs of different shapes, such as lengths and / or angles of coupling of the club head 10 to the shaft 42. it can.

  The pin extension 46 is preferably arranged eccentrically with respect to the pin body 48. That is, the geometric center of the pin extension 46 is preferably offset from the geometric center of the pin body 48. In other words, the longitudinal axis of the pin extension 46 does not coincide with the longitudinal axis of the pin body 48. By placing the pin extension 46 in a preferred arrangement, the pin 40 can be properly arranged in the hole 44 with respect to the rotational orientation.

  Pin 40 preferably includes a pin base 50, which is a portion of a third different outer diameter. The pin base 50 is preferably integral with the pin body 48 and preferably extends coaxially from its lower side. The outer diameter of the pin base 50 is preferably only slightly smaller than the outer diameter of the pin body 48. In other words, the pin body 48 transitions to the pin base 50 with only a slight step or taper. The pin base 50 is shaped to form a lower gap between the outer surface thereof and the inner wall portion of the main channel 52. For example, when the outer diameter of the pin body 48 is approximately equal to the diameter of the main channel 52 in the hole 44, the lower gap 58 is 0.015 inches between the outer surface of the pin base 50 and the inner collar of the main channel 52. The shape of the pin base 50 is determined so as to form a gap.

  Pin 40 is preferably secured within hole 44 by a binder. The binder is, for example, a flexible epoxy that preferably has a cure hardness of less than about 63 Shore D. An example of a suitable commercially available epoxy is St. Minnesota. DP-105 Clear Scotch-Weld ™ available from Pall 3M, and its hardness when cured is about 39 Shore D.

  The epoxy adhesive preferably fills the upper gap 56 and the lower gap 58 and produces a damping action in transmitting vibrations from the club head 10 to the shaft 42. The damping action is derived from the viscoelastic characteristics of the epoxy, and the vibration energy generated when the club head 10 hits the golf ball flows out as parasitic energy due to this characteristic. Even though the adhesive preferably surrounds the pin 40 within the hole 44, the upper gap 56 and the lower gap 58 contain more adhesive volume than other portions of the hole 44. Therefore, the upper gap 56 and the lower gap 58 are regions that can be greatly attenuated as compared with other portions of the hole 44.

  In a traditional muscle back iron club configuration, the center of gravity (CG) of the club is essentially closer to the hosel. In other words, CG is more than the heel with respect to the face center (FC). This point is defined as the center point of the score line, as measured when the club sole is placed at the address location, at a distance of 13.826 mm (0.591 inches) above the ground plane. However, the more preferred position of the CG is near the FC, corresponding to the most likely ball collision position.

  Also, the normal muscle back long iron CG is in a relatively high position, which results in a low flight pattern and does not work well if the strike is off center. Therefore, the more preferable CG of the long iron becomes closer to the ground plane when the club sole is arranged at the address position. For both muscleback and cavityback short irons, the position of the CG is generally not as important to the overall performance of the club as other factors. For this reason, the position of CG in the short iron is preferably within a desired range.

  FIG. 21 shows a schematic front and bottom view showing various reference points described in relation to CG, FC, and primarily CG location.

  Example 1: Comparative example of muscle back. Table 5 compares the CG position of a normal muscle back iron with a muscle back icon manufactured according to an embodiment of the invention as shown in FIGS. A typical club is Titleist 690MB, a forged stainless steel muscle back club. Three club numbers were compared. That is, they are a 3 iron, a 6 iron, and a 9 iron.

  As shown in Table 5, the CG of the muscle back club of the present invention is generally closer to FC than a normal club. This is because the material was redistributed from hole to pin.

  Table 6 shows the moment of inertia of each of these clubs. As described above, the position of the CG affects the inertia. Inertia is measured about the various axes of the club head as described above. Higher rotational moments of inertia indicate a greater rotational mass, resulting in less rotation from off-center strikes, and therefore flying farther away from the center and closer to the intended path. As shown in Table 6, the club of the present invention increases the inertia compared to the conventional club.

  Example 2: Comparative example of cavity back. Table 7 compares the CG position of a normal cavity back iron with a cavity back icon manufactured according to an embodiment of the present invention as shown in FIGS. A typical club is Titleist 704CB, a forged stainless steel cavity back club. The 3 irons from each club set were tested and compared.

  As shown in Table 7, the CG of the cavity back club of this invention is generally closer to FC than that of 704CB. This is because the material was redistributed from hole to pin.

  It will be apparent that the exemplary embodiments of the invention disclosed herein achieve the above objectives, but it will be readily apparent to those skilled in the art that many modifications and other embodiments can be implemented. Will. Therefore, it is to be understood that the appended claims cover such modifications and examples and are within the spirit and scope of this invention.

  It is clear that the embodiments of the present invention described above realize the object of the present invention, but it is obvious that those skilled in the art can easily implement various modifications and other embodiments. Also, the features or elements of any of the above-described embodiments can be used alone or in combination with other embodiments. It is to be understood that the claims are intended to cover such modifications and changes as may fall within the spirit of the invention.

1 is a front view showing a club head (a groove is omitted for clarity) of one embodiment of the present invention. FIG. It is a rear view of the club head of FIG. FIG. 2 is an isometric rear view of the club head of FIG. 1. It is a top view of the club head of FIG. It is a figure which shows the sole of the club head of FIG. It is a figure which shows the heel of the club head of FIG. It is a figure which shows the toe of the club head of FIG. It is an isometric rear view of a club head according to another embodiment of the present invention. It is a figure of the enlarged photograph of the fine structure of the forge metal optimal for using for the club head of this invention. FIG. 10 is an enlarged photograph of the microstructure after annealing the forging material of FIG. 9. It is a graph which shows the cavity volume of the club head of this invention. It is a graph which shows the area of the striking zone of the club head of this invention. It is a graph which shows the example of the minimum thickness of the striking zone of the club head of this invention. FIG. 14 is a graph showing the aspect ratio between the area of the striking zone of FIG. 12 and the minimum thickness of the striking zone of FIG. 13. It is sectional drawing of the club of FIG. It is a cross-section partial side view of a club head according to another embodiment of the present invention. It is a cross-section partial side view of a club head according to another embodiment of the present invention. FIG. 17 is a rear sectional view showing the club head of FIG. 16 except for a pin element. It is a perspective view from the bottom face of the club head of FIG. FIG. 17 is a perspective view of a pin element of the club head of FIG. 16. FIG. 17 is a rear sectional view of the club head of FIG. 16. It is a schematic diagram of the iron club which shows the rule of a position and a name.

Explanation of symbols

10 club head 12 front 14 back 16 top 18 sole 20 heel 22 toe 24 hosel 26 impact zone 28 upper part 30 reinforcing part 32 circumference 36 outer edge 40 pin 42 club shaft 44 hole 46 pin extension part 48 pin body 50 pin base 51 bottom face 52 Main channel 54 Upper channel 55 Upper shoulder 56 Upper gap 58 Lower gap

Claims (29)

  A hosel and a hole extending from the hosel toward the sole of the club head, wherein the club head is manufactured from forged stainless steel and the density of the pins disposed in the hole is less than the density of the club head A golf club characterized by that.   The golf club according to claim 1, wherein at least two attenuation regions are set in the hole.   3. The golf club according to claim 2, wherein the pin and the hole have a size and a shape so as to set the at least two attenuation regions.   The golf club according to claim 2, wherein the pin is surrounded by a flexible epoxy.   A golf club having a hosel and a hole extending from the hosel toward a sole of a club head, wherein at least two attenuation regions are set in the hole. A hosel coupled to the heel of the golf club head;
A hole provided in the heel of the club head and extending from the top of the hosel through the sole of the club head;
The hole is sized and shaped to receive a long pin;
The pin is disposed in the hole such that an upper gap is formed between the upper extended end of the pin and the inner wall of the hole; and
The golf club according to claim 1, wherein the upper gap is filled with an adhesive.   The golf club according to claim 6, wherein a lower gap is formed between a lower base end of the pin and an inner wall portion of the hole.   The golf club according to claim 7, wherein the lower gap is filled with an adhesive.   The golf club according to claim 6, wherein the pin is solid.   The golf club according to claim 6, wherein the pin is hollow.   The golf club according to claim 6, wherein the pin is formed of a material selected from the group consisting of magnesium, aluminum, and a polymer.   The golf club according to claim 6, wherein the adhesive is a flexible epoxy.   The golf club according to claim 6, wherein an outer diameter of the upper extension end is smaller than an outer diameter of the lower base end.   The golf club according to claim 6, wherein a bottom surface of the pin just overlaps an outer surface of the sole.   The golf club according to claim 6, wherein a bottom surface of the pin does not extend to an outer surface of the sole.   The golf club according to claim 15, wherein a cap is inserted into the hole.   The golf club according to claim 6, wherein the pin and the hole have a key structure so that the pin is aligned with the hole in a specific direction. Hitting face,
Hosel,
A hole through the hosel,
The center of gravity of the club head measured along the horizontal axis of the striking face is closer to the center of the face than the center of gravity of a similar club head without the hole. A golf club head for an iron golf club, wherein the golf club head is dispersed so as to approach the golf club head.   The golf club head of claim 18, wherein the horizontal offset is about 3.5 mm or less.   The golf club head of claim 18, wherein the horizontal offset of the center of gravity is not greater than about 2.3 mm.   The golf club head of claim 18, wherein the horizontal offset of the center of gravity is about 1.9 mm or less.   The golf club head of claim 18, wherein the horizontal offset of the center of gravity is about 1.5 mm or less.   The golf club head of claim 18, wherein the horizontal offset of the center of gravity is about 1.2 mm or less.   19. A golf club head according to claim 18, wherein the center of gravity of the club head is closer to the center of the face than the center of gravity of a similar club head, except that there is no pin. Hitting face,
Saul and
Hosel,
A hole extending from the hosel to the sole in the heel of the club head;
The club head so that the distance from the ground plane to the center of gravity of the club head measured when the club head is located at the address position is closer to the ground plane than the center of gravity of a similar club head without holes A golf club head for an iron golf club, wherein the mass of the golf club head is dispersed.   26. A golf club head according to claim 25, wherein the distance is about 18.45 mm or more.   26. A golf club head according to claim 25, wherein the distance is about 18.9 mm or more.   26. A golf club head according to claim 25, wherein the distance is about 19.1 mm or more.   26. A golf club head according to claim 25, wherein the distance is about 19.4 mm or more.