Patent Publication Number: US-9889349-B1

Title: Golf club head having stress-reducing structures

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     The present invention is a continuation-in-part of U.S. patent application Ser. No. 15/051,361, filed on Feb. 23, 2016, which is a continuation-in-part of U.S. patent application Ser. No. 14/997,199, filed on Jan. 15, 2016, which is a continuation-in-part of U.S. patent application Ser. No. 14/788,326, filed on Jun. 30, 2015, and is also a continuation-in-part of U.S. patent application Ser. No. 14/794,578, filed on Jul. 8, 2015, and is also a continuation-in-part of U.S. patent application Ser. No. 14/622,606, filed on Feb. 13, 2015, and issued on May 24, 2016, as U.S. Pat. No. 9,345,936, which is a continuation of U.S. patent application Ser. No. 13/906,572, filed on May 31, 2013, and issued on Feb. 17, 2015, as U.S. Pat. No. 8,956,244, the disclosure of each of which is hereby incorporated by reference in its entirety herein. The present invention is also a continuation-in-part of U.S. patent application Ser. No. 14/713,090, filed on May 15, 2015, and issued on May 31, 2016, as U.S. Pat. No. 9,352,199, which is a continuation of U.S. patent application Ser. No. 14/159,262, filed on Jan. 20, 2014, and issued on Jun. 30, 2015, as U.S. Pat. No. 9,067,110, which claims priority to U.S. Provisional Patent Application No. 61/886,473, filed on Oct. 3, 2013, the disclosure of each of which is hereby incorporated by reference in its entirety herein. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a golf club head. More specifically, the present invention relates to a golf club head with stress-reducing stiffening members disposed proximate a striking face and composed of a high-strength material such as titanium alloy. 
     Description of the Related Art 
     The prior art discloses various golf club heads having interior structures. For example, Yabu, U.S. Pat. No. 6,852,038 for a Golf Club Head And Method OF Making The Same, discloses a golf club head with a sound bar, Galloway, U.S. Pat. No. 7,118,493 for a Multiple Material Golf Club Head discloses a golf club head with a composite aft body having an interior sound component extending upward from a sole section of a metal face component, Seluga et al., U.S. Pat. No. 8,834,294 for a Golf Club Head With Center Of Gravity Adjustability discloses a golf club head with a tube having a mass for adjusting the CG of a golf club head, and Dawson et al., U.S. Pat. No. 8,900,070 for a Weighted Golf Club Head discloses a golf club head with an interior weight lip extending from the sole towards the face. However, the prior art fails to disclose an interior structure that increases ball speed through reducing stress in the face at impact, with a minimal increase in mass to the golf club head. 
     BRIEF SUMMARY OF THE INVENTION 
     The golf club head comprises a plurality of interior structures located proximate a rear surface of a striking face to reduce the stress in the face during impact with a golf ball. In a preferred embodiment, the structures are stiffening members that can be tightened or loosened by a golfer to adjust the stresses placed on the golf club head, and particularly its striking face. 
     One aspect of the present invention is a golf club head comprising a body comprising a striking face, a sole section, and a crown section, the body defining a hollow interior, and at least one stiffening member extending from the crown section to the sole section through the hollow interior, wherein the striking face comprises a face center and an interior surface facing the hollow interior, wherein the at least one stiffening member is disposed within 0.500 inch of the interior surface along a vertical plane extending through the face center perpendicular to the striking face, and wherein when the striking face makes contact with a golf ball traveling at approximately 100 mph, the at least one stiffening member comprises a first load value, the striking face comprises a second load value, and the first load value is at least 30% of the second load value. In some embodiments, the first load value may be at least 45% of the second load value. In other embodiments, the first load value may be at least 1250 lbf and the second load value may be at least 2750 lbf. In still other embodiments, the at least one stiffening member may comprise first, second, and third stiffening members, and may be preloaded at 125 lbf to 1000 lbf. 
     In some embodiments, the at least one stiffening member may comprise a midsection with a structure selected from the group consisting of a solid rod, a hollow tube, and a spring. In a further embodiment, the midsection may have a diameter ranging from 0.050 inch to 0.200 inch. In other embodiments, the at least one stiffening member may have a length ranging from 1 inch to 2.5 inches, and may be composed of a metal alloy, which may be selected from the group consisting of steel and titanium alloy. In any of the embodiments disclosed herein, the golf club head may be selected from the group consisting of a putter-type head, an iron-type head, a wedge-type head, a hybrid-type head, a fairway wood-type head, and a driver-type head. 
     Another aspect of the present invention is a golf club head comprising a body comprising a striking face, a sole section and a crown section, the body defining a hollow interior, at least one first boss comprising a bore with a first plurality of threads, at least one second boss comprising a bore with a ledge, and at least one stiffening member extending from the crown section to the sole section through the hollow interior, wherein the at least one stiffening member comprises a head portion, an end portion comprising a second plurality of threads, and a midsection connecting the head portion to the end portion, wherein the at least one stiffening member is at least partially composed of a metal alloy, wherein the crown section comprises at least one crown aperture corresponding to the at least one first boss, wherein the sole section comprises at least one sole aperture corresponding to the at least one second boss, wherein the head portion abuts the ledge, the midsection extends through the hollow interior, and the second plurality of threads engages the first plurality of threads, and wherein torqueing the head portion causes the end portion to move upwards within the first boss and the crown section to move toward the sole section. 
     In some embodiments, the midsection may comprise a structure selected from the group consisting of a solid rod, a hollow tube, and a spring. In other embodiments, the striking face may comprise a face center and an interior surface facing the hollow interior, and the at least one stiffening member may be disposed within 0.500 inch of the interior surface along a vertical plane extending through the face center perpendicular to the striking face. In still other embodiments, the golf club head may have a maximum vertical height, and the at least one stiffening member may have a length that is greater than the maximum vertical height. In any of these embodiments, when the striking face makes contact with a golf ball traveling at approximately 100 mph, the at least one stiffening member may comprise a first load value, the striking face may comprise a second load value, and the first load value may be at least 12% of the second load value. 
     Yet another aspect of the present invention is a golf club head comprising a body comprising a striking face, a sole section and a crown section, the body defining a hollow interior, at least one first boss comprising a bore with a ledge, at least one second boss comprising a bore with first a plurality of threads, and at least one stiffening member extending from the crown section to the sole section through the hollow interior, wherein the at least one stiffening member comprises a head portion, an end portion comprising a second plurality of threads, and a midsection connecting the head portion to the end portion, wherein the at least one stiffening member is disposed within 0.500 inch of an interior surface of the striking face, wherein the crown section comprises at least one crown aperture corresponding to the at least one first boss, wherein the sole section comprises at least one sole aperture corresponding to the at least one second boss, wherein the head portion abuts the ledge, the midsection extends through the hollow interior, and the second plurality of threads engages the first plurality of threads, and wherein torqueing the head portion causes the end portion to move downwards within the first boss and the sole section to move toward the crown section. In some embodiments, when the striking face makes contact with a golf ball traveling at approximately 100 mph, the at least one stiffening member may comprise a first load value, the striking face may comprise a second load value, and the first load value may be at least 30% of the second load value. In a further embodiment, the first load value may be at least 45% of the second load value. 
     Another aspect of the present invention is a golf club head comprising a body comprising a striking face, a sole section and a crown section, the body defining a hollow interior, and at least one adjustable length stiffening member extending from the crown section to the sole section through the hollow interior, wherein the at least one adjustable length stiffening member comprises a spoke and a cap, wherein the spoke comprises first and second threaded ends connected by a midsection, wherein the cap comprises an internally threaded counterbore, wherein the second threaded end engages the internally threaded counterbore, wherein the crown section comprises at least one crown aperture corresponding to the at least one adjustable length stiffening member, wherein the sole section comprises at least one sole aperture corresponding to the at least one adjustable length stiffening member, and wherein the midsection comprises a structure selected from the group consisting of a solid rod, a hollow tube, and a spring. 
     Yet another aspect of the present invention is a method comprising providing a golf club head body with a striking face, a sole section having at least one sole aperture corresponding with a first boss having a bore and an internal ledge, and a crown section having at least one crown aperture corresponding with a second boss having an internally threaded bore, the body defining a hollow interior and having a maximum vertical height, providing at least one stiffening member comprising a head portion, a midsection, a threaded end portion, and a length that is greater than the maximum vertical height, threading the threaded end of the stiffening member through the sole aperture and the hollow interior and engaging the threaded end with the threaded bore, torqueing the stiffening member until the head portion abuts the internal ledge and the at least one stiffening member has a desired preload value, and removing any portion of the stiffening member extending above the crown aperture. In some embodiments, the method may further comprise the step of permanently affixing the at least one stiffening member to the golf club head body via welding, brazing, soldering, or applying an adhesive material. 
     Having briefly described the present invention, the above and further objects, features, and advantages thereof will be recognized by those skilled in the pertinent art from the following detailed description of the invention when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a top plan view of a first embodiment of the golf club head of the present invention. 
         FIG. 2  is a sole perspective view of the golf club head shown in  FIG. 1 . 
         FIG. 3  is a top perspective view of the golf club head shown in  FIG. 1  with the crown section removed to illustrate an interior. 
         FIG. 4  is a cross-sectional view of the golf club head shown in  FIG. 3  along lines  4 - 4 . 
         FIG. 5  is a cross-sectional view of the golf club head shown in  FIG. 3  along lines  5 - 5  without the tubes. 
         FIG. 6  is another view of the embodiment shown in  FIG. 5 . 
         FIG. 7  is a cross-sectional view of the golf club head shown in  FIG. 3  along lines  7 - 7  at impact with a golf ball, with stress illustrated via shading. 
         FIG. 8  is a cross-sectional view of the golf club head shown in  FIG. 3  along lines  8 - 8  at impact with a golf ball, with stress illustrated via shading. 
         FIG. 9  is a chart illustrating the load placed on the striking face section and the stiffening members during a 100 mph impact with a golf ball. 
         FIG. 10  is a side perspective view of the golf club head shown in  FIG. 1  with the stiffening members protruding from the apertures in the return section. 
         FIG. 11  is a sole perspective view of the golf club head shown in  FIG. 10 . 
         FIG. 12  is a front, partially transparent, perspective view of the golf club head shown in  FIG. 10 . 
         FIG. 13  is a front perspective view of the golf club head shown in  FIG. 10  after excess stiffening material has been removed. 
         FIG. 14  is a cross-sectional view of the golf club head shown in  FIG. 13  along lines  14 - 14 . 
         FIG. 15  is a side elevational view of a stiffening member of the present invention. 
         FIG. 16  is a front perspective view of another embodiment of the golf club head of the present invention. 
         FIG. 17  is a partially transparent view of the embodiment shown in  FIG. 16 . 
         FIG. 18  is a front elevational view of the embodiment shown in  FIG. 16 / 
         FIG. 19  is a front elevational view of another embodiment of the golf club head of the present invention with the striking face section removed. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A preferred embodiment of the golf club head  10  of the present invention is shown in  FIGS. 1-8 and 10-15 . The golf club head  10  includes a body  20  having a sole section  22  that attaches to a lower edge of a striking face section  30 , a return section  32  extending away from an upper edge of the striking face section  30 , a hosel  24  for engaging a shaft, a heel end  23 , a toe end  25 , an upper opening  26 , a hollow interior  27 , and an aft end  28 . A crown section  40  is comprised of the return section  32  and a crown insert  42  that is placed over the upper opening  26  to enclose the hollow interior  27 . Within the hollow interior  27 , multiple stiffening members  50  (preferably two to eight, and more preferably three or four) extend from the sole section  22  upward to the return section  32 . In an alternative embodiment, the stiffening members  50  may extend to the crown insert  42  instead; what is important is that the stiffening members  50  connect the crown section  40  to the sole section  22  in close proximity to the striking face section  30 . 
     As shown in  FIG. 3 , the preferred embodiment has three stiffening members  50 . Each of the stiffening members  50  in the preferred embodiment comprises a midsection  52  composed of a solid, lightweight, strong metal material such as titanium alloy or steel, though in an alternative embodiment each midsection  52  of the stiffening members  50  may be hollow (e.g., a hollow tube) and be comprised of a strong, lightweight metal or a composite material. In yet another, alternative embodiment, the midsection  52  may comprise a spring structure. In another embodiment, the golf club head  10  may include one or more of the solid, hollow, and spring types of stiffening members  50 . In the preferred embodiment, each of the stiffening members  50  has a head portion  54  and a threaded end portion  56  separated from the head portion  54  by the midsection  52 , and has a diameter ranging from 0.050 inch to 0.200 inch. An exemplary stiffening member  50  is shown in  FIG. 16 . If any of the stiffening members  50  includes a hollow tube portion, that stiffening member preferably has a total mass that ranges from 0.5 gram to 3 grams, more preferably from 1 gram to 2 grams, and most preferably 1.5 grams. 
     The return section  32  (or in the alternative embodiment, the crown insert  42 ) preferably comprises a first plurality of apertures  44 , each of which leads to a first, internally threaded boss  47  that extends downwards from the return section  32 . Each of the first plurality of apertures  44 , and each of the first, internally threaded bosses  47 , preferably corresponds to one of the stiffening members  50 . The sole section  22  comprises a second plurality of apertures  46 , each of which leads to a second, unthreaded boss  48  that extends upwards from the sole section  22  into the hollow interior  27 . Each of the plurality of second, unthreaded bosses  48  preferably corresponds to a stiffening member  50 , and each of the unthreaded bosses  48  includes a ledge  49  which the head portion  54  of the stiffening member  50  abuts and presses against when the stiffening member  50  is torqued within the golf club head  10 . 
     As shown in  FIGS. 10-12 , each of the stiffening members  50  preferably has a length L 1  that is greater than the greatest vertical height H of the golf club head  10 . Each stiffening member  50  is inserted into an aperture  46  in the sole section  22  and pushed through the hollow interior  27  of the golf club head  10  so that the head portion  54  abuts the ledge  49  and the threaded end portion  56  engages the internally threaded boss  47  located directly above the aperture  46  into which the stiffening member  50  was inserted. In an alternative embodiment, shown in  FIGS. 16-18 , the threading is reversed, such that the apertures  44  in the return section  32  lead to the unthreaded boss  48  with the ledge  49  and the apertures  46  in the sole section lead to the internally threaded boss  47 , and the stiffening members  50  are inserted into the golf club head  10  via the apertures  44  in the return section  32 . In yet another alternative embodiment, shown in  FIG. 19 , the stiffening members  50  are made of two pieces, a spoke  80  with two threaded ends  82 ,  84  on either side of a midsection  83 , and a cap  85  with a threaded counterbore  87 . This construction allows a user to adjust the overall length L 1  of the stiffening members  50  by controlling how far into the threaded counterbore  87  the spoke  80  extends, and can be used in either of the golf club head  10  embodiments discussed above and shown in  FIGS. 10-18 . The midsection  83  of the spoke  80  may include a hollow tube, a solid rod, or a spring structure. 
     Regardless of how the stiffening members  50  are assembled or inserted into the golf club head  10 , the threading in each internally threaded boss  47  allows the stiffening member  50  to which it corresponds to be preloaded in the golf club head  10 . Preloading is accomplished using a tool, such as a torque wrench or a screwdriver, which engages the head portion  54  of the stiffening member  50  to torque the stiffening member  50  such that the threaded end portion  56  engages the threads of the internally threaded boss  47  and pulls the return section  32  towards the sole section  22 . Preloading each stiffening member  50  reduces the peak stress placed on the striking face section  30  when the golf club head  10  impacts a golf ball  100 , and thereby reduces the risk that the striking face section  30  will crack under impact load. When all of the stiffening members  50  are preloaded as described above, the peak stress placed on the region  45  of the body  20  located between the stiffening members  50  and the striking face section during impact with a golf ball  100  is also lowered. In other words, preloading improves the resilience of the golf club head  10  during impact with a golf ball  100  by distributing the stresses more evenly. In order to achieve these desirable results, it is preferable to torque the stiffening members  50  so they collectively have a load value of at least 375 lbf, or at least 12% of the load value placed on the striking face section  30 , more preferably at least 1250 lbf, or at least 30% of the load value placed on the striking face section  30 , and most preferably at least 45% of the load value placed on the striking face section  30  (e.g., at least 2750 lbf) when it makes contact with a golf ball  100  at approximately 100 mph, as shown in  FIG. 9 . Individually, each stiffening member  50  preferably should be preloaded to a range of 125-1000 lbf to achieve this result. 
     Once the stiffening members  50  are preloaded to a desired load value, any excess length L 2  extending through the apertures  44  in the return section  32  is removed by any means known to a person of ordinary skill in the art, including but not limited to machining. This step can be bypassed if the adjustable length stiffening members  50  shown in  FIG. 19  are used. The stiffening members  50  can then be permanently affixed to the golf club head via welding, brazing, or soldering, or with an adhesive such as Loctite®, though this step is not required and can be bypassed if a golfer wants to retain the ability to adjust the load placed on the stiffening members  50 . 
     As shown in  FIG. 4 , in each of the embodiments disclosed herein, each stiffening member  50  preferably is located less than 0.500 inch from the interior surface  36  of the striking face section  30 , measured along a vertical plane  60  extending through the face center  34  perpendicular to the striking face section  30 . No portion of any stiffening member  50  should be disposed outside of this 0.500 inch range. As shown in  FIG. 5 , the middle stiffening member  50  preferably is disposed within 0.250 inch, toe-wards or heel-wards, of the face center  34  along a horizontal Y-axis  70  extending parallel to the striking face section  30 . The other two stiffening members  50  preferably are each disposed within 1 inch, toe-wards and heel-wards, of the face center  34  along the horizontal Y-axis  70 . 
     Locating the stiffening members  50  within the region of the golf club head  10  defined above and in  FIGS. 4 and 5  has the greatest stress-reducing effect on the golf club head  10 . If any of the stiffening members  50  are placed more than 0.500 inch away from the interior surface  36  of the striking face section  30  or outside of the 0.250/1 inch range, they will not have a noticeable effect on the stress placed on the striking face section  30  when the golf club head  10  is in use, and will use up discretionary mass without creating a significant performance benefit. 
     In each of the embodiments disclosed herein, the golf club head  10  preferably has a characteristic time (CT) of the face close to, but not exceeding, the 257 microsecond (“μS”) limit set by the USGA. 
     The stiffening members of the present invention may be used as described herein in any type of golf club head with a hollow interior, including putters, irons, wedges, hybrids, fairway woods, and drivers. In any of the embodiments disclosed herein, when the golf club head  10  is designed as a driver, it preferably has a volume from 200 cubic centimeters to 600 cubic centimeters, more preferably from 300 cubic centimeters to 500 cubic centimeters, and most preferably from 420 cubic centimeters to 470 cubic centimeters, with a most preferred volume of 460 cubic centimeters. In fact, in the preferred embodiment, the golf club head  10  has a volume of approximately 450 cc to 460 cc. 
     The volume of the golf club head  10  will also vary between fairway woods (preferably ranging from 3-woods to eleven woods) with smaller volumes than drivers. When designed as a driver, the golf club head  10  preferably has a mass no more than 215 grams, and most preferably a mass of 180 to 215 grams; when designed as a fairway wood, the golf club head  10  preferably has a mass of 135 grams to 200 grams, and preferably from 140 grams to 165 grams. 
     In each of the embodiments disclosed herein, the striking face section  30  preferably has a varying thickness such as that described in U.S. Pat. No. 7,448,960, for a Golf Club Head With Variable Face Thickness, which pertinent parts are hereby incorporated by reference. Other alternative embodiments of the thickness of the striking face section  30  are disclosed in U.S. Pat. No. 6,398,666, for a Golf Club Striking Plate With Variable Thickness, U.S. Pat. No. 6,471,603, for a Contoured Golf Club Face and U.S. Pat. No. 6,368,234, for a Golf Club Striking Plate Having Elliptical Regions Of Thickness, all of which are owned by Callaway Golf Company and which pertinent parts are hereby incorporated by reference. Alternatively, the face section has a uniform thickness. 
     In each of the embodiments disclosed herein, the body  20  is preferably cast from molten metal in a method such as the well-known lost-wax casting method. The metal for casting is preferably titanium or a titanium alloy such as 6-4 titanium alloy, alpha-beta titanium alloy or beta titanium alloy for forging, and 6-4 titanium for casting. Alternatively, the body  20  is composed of 17-4 steel alloy. Additional methods for manufacturing the body  20  include forming the body  20  from a flat sheet of metal, super-plastic forming the body from a flat sheet of metal, machining the body  20  from a solid block of metal, electrochemical milling the body  20  from a forged pre-form, casting the body  20  using centrifugal casting, casting the body  20  using levitation casting, and like manufacturing methods. 
     In other embodiments, the golf club head  10  may have a multi-material composition such as any of those disclosed in U.S. Pat. Nos. 6,244,976, 6,332,847, 6,386,990, 6,406,378, 6,440,008, 6,471,604, 6,491,592, 6,527,650, 6,565,452, 6,575,845, 6,478,692, 6,582,323, 6,508,978, 6,592,466, 6,602,149, 6,607,452, 6,612,398, 6,663,504, 6,669,578, 6,739,982, 6,758,763, 6,860,824, 6,994,637, 7,025,692, 7,070,517, 7,112,148, 7,118,493, 7,121,957, 7,125,344, 7,128,661, 7,163,470, 7,226,366, 7,252,600, 7,258,631, 7,314,418, 7,320,646, 7,387,577, 7,396,296, 7,402,112, 7,407,448, 7,413,520, 7,431,667, 7,438,647, 7,455,598, 7,476,161, 7,491,134, 7,497,787, 7,549,935, 7,578,751, 7,717,807, 7,749,096, and 7,749,097, the disclosure of each of which is hereby incorporated in its entirety herein. 
     From the foregoing it is believed that those skilled in the pertinent art will recognize the meritorious advancement of this invention and will readily understand that while the present invention has been described in association with a preferred embodiment thereof, and other embodiments illustrated in the accompanying drawings, numerous changes, modifications and substitutions of equivalents may be made therein without departing from the spirit and scope of this invention which is intended to be unlimited by the foregoing except as may appear in the following appended claims. Therefore, the embodiments of the invention in which an exclusive property or privilege is claimed are defined in the following appended claims.