Patent Publication Number: US-2009221383-A1

Title: Wood Club Head

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a wood club head having a loft angle of 13° or more, or a head of so-called fairway wood. 
     2. Description of the Related Art 
     In a conventional fairway wood, the amount of spin, the ball grippability, and the like are designed by variously changing the values of a barycenter depth (ZG) representing the distance from the face to the barycenter, a face progression (FP) representing the distance from the shaft axis to the leading edge of the face, and a hosel length representing the length of the cylindrical portion of the hosel. When the value ZG is large, the face tends to be directed more upward upon impact, and the ball can spin and rise higher more easily. The larger the FP value, the more easily the ball tends to rise high, but the worse ball grippability becomes. A loft angle is the measurement value of an angle formed by the shaft and face when the face is set in a square state, and represents the upward angle of the face. For an ordinary golfer whose head speed is not high, a fairway wood is generally designed to grip and spin the ball well so the ball rises high easily. 
     As a golf club head that is focused on the FP value, one with an FP vale falling within a range of 7 mm to 20 mm (both inclusive) is known (for example, see Japanese Patent Laid-Open No. 11-178958). Another golf club head that is focused on the barycenter depth (ZG) is also known (for example, Japanese Patent Laid-Open No. 2002-210045). 
     None of Japanese Patent Laid-Open Nos. 11-178958 and 2002-210045 provides a golf club head which is designed by combining the ZG and FP values and the hosel length of the fairway wood so that a golfer having a high head speed can hit a ball with it easily. If only the ZG and FP values are so designed that the ball can rise high easily, when the golfer having a high head speed hits a ball with the golf club head, the ball rises too high. Such a ball tends to yield to the wind and lose its traveling distance. 
     SUMMARY OF THE INVENTION 
     The present invention is made by taking also the hosel length into account, and has as its object to provide a wood club head which can be adapted to different hosel lengths so that when a golfer having a high head speed hits a ball with it, the ball can rise high easily but does not rise too high, providing a strong trajectory and a long traveling distance. 
     According to the present invention, there is provided a wood club head having a loft angle of not less than 13°, wherein a hosel length is of not less than 20 mm, a face progression (FP value) is set to fall within a range of 12 mm to 16 mm (both exclusive), and a barycenter depth is set to fall within a range of 20 mm to 25 mm (both exclusive). 
     According to the present invention, since the hosel length is of not less than 20 mm, the club head tends to draw a sweep (obtuse) trajectory upon impact and the loft tends to be at a high angle so that the ball tends to rise high easily. By decreasing the ZG value and FP value, the ball does not rise too high, so that a strong trajectory can be obtained. The traveling distance also increases. 
     According to the present invention, there is provided a wood club head having a loft angle of not less than 13°, wherein a hosel length is of not more than 20 mm, a face progression (FP value) is set to fall within a range of 16 mm to 20 mm (both exclusive), and a barycenter depth is set to fall within a range of 25 mm to 30 mm (both exclusive). 
     According to the present invention, since the hosel length is of not more than 20 mm, the club head tends to draw a down blow (acute) trajectory upon impact and the loft tends to be at a low angle so that the ball does not rise high easily. By increasing the FP value, the face tends to be opened upon impact and by increasing the ZG so the ball spin easily, the ball is prevented from rising too high. Then, a strong ball flight and a long traveling distance can be obtained. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         FIG. 1  is a side view showing an embodiment of the present invention; and 
         FIG. 2  is a front view showing the embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE EMBODIMENT 
     A preferred embodiment of the present invention will be described with reference to the accompanying drawings. 
       FIGS. 1 and 2  are a side view and front view, respectively, of a wood club head having a loft angle of 13° or less. A head main body  1  is provided with a hosel  2 . A shaft (not shown) is fixed into the hosel  2 . The distance from a face  3  of the head main body  1  to the barycenter is defined as a barycenter depth ZG. A length HL of the hosel  2  represents the length of the cylindrical portion. The distance from a shaft axis S to a leading edge  4  is defined as a face progression (FP). 
     As the head main body  1 , the embodiment used one which was made by casting stainless steel and had a volume falling within a range of 150 cm 3  to 250 cm 3  and a head weight falling within a range of 200 g to 250 g. When the vertical distance from a sole  5  of the head main body  1  to a barycenter position CG was defined as a barycenter height, the barycenter height was designed to 18 mm or less. The club length was 43 inches or less, and the total weight was 300 g or more. In such a fairway wood, the FP value (mm), ZG value (mm), and hosel length (mm) were changed to provide Examples 1 and 2 and Comparative Examples 1 to 6. A golfer having a head speed of 45 m/sec to 50 m/sec actually hit a ball with the manufactured fairway woods. The respective launch angles and amounts of spin were measured. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                   
                   
                   
                 Launch- 
                   
                   
               
               
                   
                   
                   
                 Hosel 
                 ing 
                 Spin 
               
               
                   
                 FP 
                 ZG 
                 Length 
                 Angle 
                 Amount 
                 Evaluation 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Comparative 
                 14 
                 23 
                 10 
                 8 
                 2700 
                 Not high 
               
               
                 Example 1 
                   
                   
                   
                   
                   
                 enough 
               
               
                 Example 1 
                 14 
                 23 
                 30 
                 10 
                 3500 
                 Good 
               
               
                 Comparative 
                 14 
                 27 
                 10 
                 9 
                 3900 
                 Slightly too 
               
               
                 Example 2 
                   
                   
                   
                   
                   
                 high 
               
               
                 Comparative 
                 14 
                 27 
                 30 
                 11 
                 4200 
                 Too high 
               
               
                 Example 3 
               
               
                 Comparative 
                 18 
                 23 
                 10 
                 10 
                 2500 
                 Too strong 
               
               
                 Example 4 
               
               
                 Comparative 
                 18 
                 23 
                 30 
                 12 
                 4100 
                 Too high 
               
               
                 Example 5 
               
               
                 Example 2 
                 18 
                 27 
                 10 
                 11 
                 3300 
                 Good 
               
               
                 Comparative 
                 18 
                 27 
                 30 
                 13 
                 4800 
                 Considerably 
               
               
                 Example 6 
                   
                   
                   
                   
                   
                 too high 
               
               
                   
               
            
           
         
       
     
     In Table 1, shorthosel (10 mm) fairway woods were made with a large FP and large ZG. Table 2 shows this group. Long-hosel (30 mm) fairway woods were made with a small FP and small ZG. Table 3 shows this group. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                   
                   
                   
                 Launch- 
                   
                   
               
               
                   
                   
                   
                 Hosel 
                 ing 
                 Spin 
               
               
                   
                 FP 
                 ZG 
                 Length 
                 Angle 
                 Amount 
                 Evaluation 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Comparative 
                 14 
                 23 
                 10 
                 8 
                 2700 
                 Not high 
               
               
                 Example 1 
                   
                   
                   
                   
                   
                 enough 
               
               
                 Comparative 
                 14 
                 27 
                 10 
                 9 
                 3900 
                 Slightly too 
               
               
                 Example 2 
                   
                   
                   
                   
                   
                 high 
               
               
                 Comparative 
                 18 
                 23 
                 10 
                 10 
                 2500 
                 Too strong 
               
               
                 Example 4 
               
               
                 Example 2 
                 18 
                 27 
                 10 
                 11 
                 3300 
                 Good 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
               
               
               
               
               
               
             
               
                   
                 TABLE 3 
               
               
                   
                   
               
               
                   
                   
                   
                   
                 Launch- 
                   
                   
               
               
                   
                   
                   
                 Hosel 
                 ing 
                 Spin 
               
               
                   
                 FP 
                 ZG 
                 Length 
                 Angle 
                 Amount 
                 Evaluation 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Example 1 
                 14 
                 23 
                 30 
                 10 
                 3500 
                 Good 
               
               
                 Comparative 
                 14 
                 27 
                 30 
                 11 
                 4200 
                 Too high 
               
               
                 Example 3 
               
               
                 Comparative 
                 18 
                 23 
                 30 
                 12 
                 4100 
                 Too high 
               
               
                 Example 5 
               
               
                 Comparative 
                 18 
                 27 
                 30 
                 13 
                 4800 
                 Considerably 
               
               
                 Example 6 
                   
                   
                   
                   
                   
                 too high 
               
               
                   
               
            
           
         
       
     
     This embodiment studies the fact that when the hosel length HL exceeds 20 mm, the FP value (mm) may be set to satisfy 12&lt;FP&lt;16 and the ZG value (mm) may be set to satisfy 20&lt;ZG&lt;25, so that a resultant fairway wood is suitable for a golfer having a high head speed (45 m/sec). When setting the barycenter height to 18 mm or less, it is desirable to set the hosel length HL to fall within a range of 35 mm to 40 mm (inclusive) at a maximum. In this case, if forming the hosel  2  from titanium having a small specific gravity, or its alloy, the barycenter height can be decreased even if the hosel length HL is large. 
     When a short hosel with a hosel length of 20 mm or less (0&lt;HL&lt;20) is designed, 16&lt;FP&lt;20 and 25&lt;ZG&lt;30 must be satisfied. With a short hosel that satisfies 0&lt;HL&lt;20, the club head tends to draw a down blow trajectory upon impact and the loft tends to be at a low angle, so the ball does not rise high easily. By increasing the FP value and ZG value, the ball rises high but does not rise too high, providing a strong ball flight. As a result, a long traveling distance can also be obtained. 
     The head weight desirably includes a main body weight of 190 g or more and an additional weight (a tungsten weight or the like is added to an appropriate portion) of 30 g or more. Desirably, the volume is 150 cm 3  to 250 cm 3 , the barycenter height is 18 mm or less, and the head main body  1  is made by casting stainless steel. The head volumes, club lengths, and total weights of #3 to #5 fairway woods were set as follow. The FP value and ZG value of each short hosel and each long hosel were set to fall within the ranges described above. 
     #3 . . . 168 cm 3  . . . 42.5 inches . . . 329 g 
     #4 . . . 160 cm 3  . . . 42.25 inches . . . 331 g 
     #5 . . . 155 cm 3  . . . 42 inches . . . 333 g 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2006-344484, filed Dec. 21, 2006, which is hereby incorporated by reference herein in its entirety.