Patent Publication Number: US-2003236131-A1

Title: Wood type head for a golf club

Description:
BACKGROUND OF THE INVENTION  
       [0001] This invention relates generally to improvements in golf club heads of the metal wood type. More specifically, this invention relates to a metal wood club head designed for improved dissipation of shock energy upon impact with a golf ball, to correspondingly reduce transmission of such impact shock energy typically in the form of vibrations to the club shaft.  
       [0002] Golf club heads of the so-called metal wood type are generally known in the art, wherein the shape of a traditional wood-type club head is reproduced in the form of a hollow metal shell. In a typical construction, the club head comprises a base member or body formed by casting or forging or the like in an upwardly open shell-shaped configuration defining a sole plate and upstanding club head side walls, including a front face for striking a golf ball. This base member additionally includes a hosel for suitable connection to the end of a golf club shaft. The open top of the base member is closed by a cap plate which is typically welded thereto, to form the hollow metal head structure. In an alternative configuration, the base member or body can be formed as a downwardly open shell, and a sole plate is attached thereto as by welding to form the hollow club head structure.  
       [0003] Significant development effort has been directed to improving metal wood type golf clubs, to improve distance, accuracy, and overall playability in different conditions. Much of this effort has focused upon improvements in club head weight distribution, structural stiffness, and aerodynamics.  
       [0004] U.S. Pat. No. 5,851,159 is directed to an improved metal wood golf club head having a relatively large dome element incorporated into the sole plate. This dome element comprises an upwardly extending structure that effectively adjusts the club head weighting and the location of the so-called sweet spot for optimal ball impact. In addition, this dome element has been found to reduce the transmission of vibrational energy from the club head to the club shaft, resulting from shock impact of the club head faceplate with a golf ball. Instead, a significant portion of this impact shock energy is believed to be emanated or transmitted from the club head, by means of the dome element, in the form of a distinctive and audible ringing sound.  
       [0005] While the club head shown and described in U.S. Pat. No. 5,851,159 is believed to represent a significant advance in the art, it has been found that the degree of energy transmission from the club head is restricted by the thickness of the sole plate having the dome element formed therein. In this regard, traditional metal casting processes for making metal wood style golf club heads are constrained to cast walls having a thickness on the order of at least about 0.045-0.050 inch. Thus, the cast sole plate and the integrally cast dome element as shown and described in U.S. Pat. No. 5,851,159 have a wall thickness on the order of at least about 0.045-0.050 inch. While the dome element in the sole plate provides an acoustic structure for dissipating some of the ball impact shock energy in the form of sound, it has been discovered that the transmission of energy from the club head can be significantly enhanced by forming the club head with one or more regions of reduced wall thickness, such as a thickness on the order of about 0.020 inch. Such regions of reduced wall thickness, which may be located in the sole plate and which may also have a dome-type shape, are believed to function as acoustic diaphragms for enhanced transmission of vibrational energy from the club head each time a golf ball is struck.  
       [0006] The present invention thus relates to an improved golf club head of the metal wood type, having one or more regions of reduced wall thickness formed therein to provide relatively thin acoustic diaphragms for enhanced transmission of ball impact shock energy from the club head in the form of sound.  
       SUMMARY OF THE INVENTION  
       [0007] In accordance with the invention, a golf club head of the metal wood type is provided, wherein the club head includes at least one and preferably multiple regions of reduced wall thickness. In a preferred form, the regions of reduced wall thickness are formed in the sole plate of the club head. The region or regions of reduced thickness each comprise an acoustic diaphragm which resonates or vibrates upon club head impact with a golf ball to dissipate energy as a distinctive audible sound output. As a result, transmission of vibrational energy from the club head to the associated club shaft is significantly reduced.  
       [0008] In one preferred form, the club head is defined by an upwardly open and generally shell-shaped base member or body formed by metal casting to define the sole plate bounded by upstanding side walls, including a front impact face or faceplate for striking a golf ball, a rear face, a heel segment and a toe segment. A hosel is normally incorporated into the base member generally at the heel segment thereof, wherein the hosel is adapted for connection to the lower end of a club shaft. A cap plate, which can also be formed by metal casting, is provided for connection as by welding to the upper margins of the upstanding side walls to close the open top of the base member and thereby form a hollow metal wood club head. In the as-cast form, the walls of the club head have a thickness on the order of at least about 0.045-0.050 inch.  
       [0009] The at least one and preferably multiple regions of reduced wall thickness are formed in the club head, as by machining each region of reduced wall thickness to a thickness significantly less than, and preferably about 50% of the wall thickness in the as-cast form. In one preferred configuration of the invention, each region of reduced wall thickness is machined to a thickness of the order of about 0.020 inch to define an acoustic diaphragm of relatively thin wall thickness in comparison to the wall thickness of the surrounding club head wall. These acoustic diaphragms may be formed in any selected wall of the club head, such as the sole plate, and may take the shape of one or more generally hemispherical dome elements of reduced wall thickness relative to the adjacent surrounding portions of the club head wall. Alternately, these acoustic diaphragms may be formed as flat regions of reduced wall thickness by machining the interior or exterior of the club head wall in which they are formed. Upon impact of the club head faceplate with a golf ball, each acoustic diaphragm undergoes a significant vibration or reverberation to convert ball impact shock energy to acoustic energy which is effectively transmitted from the club head as an acoustic and audible sound wave, instead of being transmitted to the club shaft for tactile detection by the golfer. 
     
    
    
     [0010] Other features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.  
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0011] The accompanying drawings illustrate the invention. In such drawings:  
     [0012]FIG. 1 is a bottom perspective view of a metal wood type golf club head embodying the novel features of the invention;  
     [0013]FIG. 2 is a top perspective view of the golf club head of FIG. 1;  
     [0014]FIG. 3 is an exploded top perspective view of the golf club head, illustrating an upper cap plate in exploded relation with a lower club head base member or body;  
     [0015]FIG. 4 is top perspective view of the lower club head base member or body, with the upper cap plate removed to reveal internal construction details;  
     [0016]FIG. 5 is a toe end elevation view of the club head;  
     [0017]FIG. 6 is an enlarged vertical sectional view taken generally on the line  6 - 6  of FIG. 5;  
     [0018]FIG. 7 is an exploded bottom perspective view illustrating one alternative preferred form of the invention; and  
     [0019]FIG. 8 is a vertical sectional view similar to FIG. 6, but showing another alternative preferred form of the invention.  
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0020] As shown in the exemplary drawings, an improved metal wood type golf club head referred to generally by the reference numeral  10  is provided. The improved club head  10  is formed from cast metal components and includes at least one and preferably a plurality of regions of reduced wall thickness, wherein these regions are identified in FIGS. 1 and 3- 6  by the reference numeral  12 . These regions  12  of reduced wall thickness are formed by machining portions of the as-cast club head to define acoustic diaphragms which undergo a significant vibration to convert ball impact shock energy to acoustic energy which is effectively transmitted from the club head as an acoustic and audible shock wave, instead of being transmitted to the club shaft  14  for tactile detection by the golfer.  
     [0021] The overall construction of the illustrative golf club head  10  generally conforms to existing metal wood technology, wherein an enclosed and hollow metal club head is formed from metal components which are typically cast from stainless steel, titantium or other selected metal or metal alloy. The club head  10  includes a base member or body  18  (FIGS.  3 - 4 ) including a hosel  20  for suitable attachment to the lower end of the club shaft  14 . As shown in the embodiment of FIGS.  1 - 6 , the base member  18  is formed as an upwardly open and generally shell-shaped structure to include a bottom sole plate  22  joined at its perimeter to upstanding side walls of the club head, namely, a front impact face  24  for striking a golf ball, a rear face  26 , a toe segment or wall  28 , and a heel segment or wall  30 . The hosel  20  is normally formed at the inboard side of the heel segment  30  and is adapted for connection to the golf club shaft  14 . These upstanding side walls of the base member or body  18  are adapted for assembly with and secure attachment to a cap plate  32  which is normally welded thereto and then appropriately surface finished to provide an attractive hollow metal golf club head.  
     [0022] These cast metal club head components, in accordance with conventional metal casting methods and processes, have an as-cast thickness which is on the order of at least about 0.045-0.050 inch. The regions  12  of reduced wall thickness are formed in a selected wall or walls of the club head  10 , and are reduced in thickness from the as-cast form as by machining to provide a local wall thickness which is substantially less than the as-cast minimum thickness. In a preferred form of the invention, each region  12  of reduced wall thickness is machined to a thickness which is about 50% of the as-cast thickness, and more preferably on the order of about 0.020 inch.  
     [0023] These regions  12  define the at least one and preferably multiple relatively thin-walled acoustic diaphragms which vibrate or resonate upon impact of the club head faceplate  24  with a golf ball, to convert the impact shock energy to acoustic energy which is transmitted from the club head as a distinctive and audible sound wave. Such acoustic transmission of the impact shock energy from the club head beneficially reduces and substantially eliminates energy transmission in the form of vibrations or the like to the club shaft  14  where it is otherwise subject to tactile detection by the golfer. As a result, with each golf shot using the club head  10  of the present invention, the golfer senses a firm and solid ball impact.  
     [0024] FIGS.  1 - 6  show three regions  12  of reduced wall thickness formed in the sole plate  22  of the metal golf club head  10 . These regions  12  are formed as upwardly extending, generally hemispherical dome elements each having a diametric size on the order of about 1 inch and arranged within the sole plate  22  in a generally triangular pattern. As viewed in FIG. 6, each of these dome elements  12  has a reduced wall thickness, in relation to the remaining and surrounding portion of the sole plate  22 . As described above, these dome elements  12  provide a trio of acoustic diaphragms which audibly ring in a clear and distinctive manner each time the club head  10  strikes a golf ball.  
     [0025]FIG. 7 illustrates an alternative form of the invention, wherein the regions or dome elements  12  of reduced wall thickness are again formed in a sole plate  22  of the club head, but wherein the sole plate  22  is formed as a separately cast component for attachment as by welding or the like onto a modified, downwardly open shell-shaped base member or body  18 . As shown, this modified base member  18  is defined by the upper cap plate  32  which is integrally cast with downwardly extending side walls including the front face  24 , a rear face  26 , a toe segment  28 , and a heel segment  30 . FIG. 7 shows the dome elements  12  in a pattern of four regions of reduced wall thickness. Persons skilled in the art will recognize and appreciate that alternative configurations of the acoustic diaphragms  12  in terms of number, size and specific geometry may be used.  
     [0026]FIG. 8 illustrates a further alternative preferred form of the invention, wherein the regions  12  of reduced wall thickness are again formed in a club head sole plate  22 . In this version of the invention, the regions  12  of reduced wall thickness are formed in the sole plate as by machining to define the acoustic diaphragms as generally flat or generally planar membranes. FIG. 7 shows the inboard surface of the sole plate  22  machined to define the reduced thickness regions  12 , whereby the resultant acoustic diaphragms are not visible from the exterior of the club head. It will be recognized and understood, however, that the outboard side of the sole plate  22  may be machined to form the reduced thickness regions  12 .  
     [0027] A variety of further modifications and improvements in and to the metal wood type golf club head of the present invention will be apparent to those persons skilled in the art. Accordingly, no limitation on the invention is intended by way of the foregoing description and accompanying drawings, except as set forth in the appended claims.