Abstract:
A simplified method of matching a golfer to a golf club and a golf ball by measuring the golfer&#39;s clubhead speed and comparing that measured value to recorded sets of data which correlates a few key variables that can accurately match the golfer with the most suitable golf club and golf ball designed to achieve optimum driving performance.

Description:
FIELD OF THE INVENTION 
     The present invention generally relates to methods for custom fitting a golfer with golfing equipment suited to that golfers individual swing characteristics. More specifically, the present invention relates to a simplified method of matching a golfer with a particular driver and golf ball designed to achieve maximum driving distance. 
     BACKGROUND OF THE INVENTION 
     Methods of custom fitting a golfer to the most suitable golf ball, taking into account different swing characteristics, are well known within the golf industry. For example, the testing laboratory at the Acushnet Golf Center in New Bedford, Mass. has been measuring and analyzing the swing characteristics and ball launch conditions of thousands of golfers since the early seventies, as described in a special editorial report in the October 1980 issue of Golf Digest. As a result of this testing, Acushnet has developed an accurate method of matching a golfer with particularized golfing equipment. This method utilizes sophisticated equipment that, while the golfer hits a variety of drivers (or number 1 clubs) having variations in head and shaft characteristics and golf balls of different construction and performance characteristics, measure the ball&#39;s launch conditions. Cameras monitor the golfer&#39;s launch conditions by tracking the movement of a cluster of light emitting diodes attached to specific locations on the golf ball. Each camera has strobe lights that emit light immediately after the golf ball is struck. The light reflects off the diodes and is captured by the camera and sent to a computer for processing. This data is then recorded and analyzed using complex mathematical models which are able to calculate, among other things, the distance that a golf ball travels when struck off the tee by the golfer. From this information, the most appropriate golf club or golf ball is then selected for that specific golfer. Although this methodology very accurately matches a golfer to a golf club and a golf ball, it requires the use of electronic measuring equipment not always readily available. Consequently, the custom club fitting industry has, in recent years, attempted to meet the need for simpler custom golf club fitting methods. 
     For example, Spalding has developed the Ball/Club System C and System T which matches Top-Flite golf balls with Callaway&#39;s Great Big Bertha and Taylor Made&#39;s TI Bubble 2 drivers. These balls were allegedly designed by matching the golf ball to the launch angle, speed and spin for use with the specific drivers. However, the Spalding system fails to consider key variables such as the golfer&#39;s swing speed, club loft angles and shaft flex. Therefore, under this system a pro golfer and a beginner using any Callaway club is directed to the same ball. Similarly, Dunlop/Maxfli has proposed a method which matches a players swing speed to a particular ball compression. However, this method fails again to consider the design of the clubhead and the club shaft. Consequently, neither of these methods adequately meets the demand for a simple, yet accurate, club fitting method. 
     SUMMARY OF THE INVENTION 
     The present invention achieves both simplicity and accuracy in its disclosed method. Unlike more complex methods, the present invention utilizes only a few key variables out of the many available to match a player to a particular club and a particular ball in a manner that maximizes driving distance. 
     The key variables, according to the present invention, include the golfer&#39;s swing characteristics, the golf club&#39;s inertial properties and shaft characteristics, and the ball&#39;s physical properties. According to the present invention, a golf club and a golf ball are selected from a plurality of golf clubs and golf balls by measuring the preferred golfer&#39;s swing characteristic and matching that characteristic to key club characteristics and ball characteristics based upon a predetermined relationship as set forth below. 
     A golfer&#39;s swing characteristics can be identified by a number of variables, such as clubhead speed and angle of attack, the direction of the golfer&#39;s swing (e.g., inside-out or outside-in), and the acceleration of the clubhead prior to impact. Most preferably, the golfer&#39;s swing characteristics are defined simply by the golfer&#39;s clubhead speed at impact. Currently, there are many simple, commercially available products that measure a golfer&#39;s clubhead speed. Such products range from simple devices that are clipped onto the club shaft and measure clubhead speed using light gates to more complex stand-alone devices that utilize radar. Although the simpler devices do not have a high degree of accuracy, they are accurate enough to classify a golfer within preferred ranges (i.e., high, medium, and low) set forth in the present invention. 
     The inertial properties and shaft characteristics of a golf club can be characterized by clubhead weight, loft angle, roll, bulge, and center of gravity position, as well as the overall flex, flex point, vibrational frequency, and torsional rigidity of the club shaft. However, in the most preferred embodiment of the invention, the club characteristics are the golf club loft and overall shaft flex for simple club fitting for optimum driving performance. 
     The physical properties of a golf ball can be characterized by type (i.e. solid or wound construction), size, weight, initial velocity or COR, spin, compression, hardness and moment of inertia. In the most preferred embodiment of the present invention, the two preferred ball characteristics are weight and spin in matching a ball to a particular player. 
     In all, dozens of variables can be considered when trying to match a golfer to a particular golf club and golf ball to achieve ultimate driving performance. However, the present invention utilizes only a few key variables to create a significantly simplified method that mimics the accuracy of the more complex Acushnet club fitting method described above. Thus, a golfer can be fitted to a club and ball combination from a plurality of clubs and balls so that the golfer&#39;s driving performance is optimized. In the preferred embodiment of the invention, the club and ball characteristics are a direct linear relationship to the players swing speed for simple fitting. The use of color coded clubs and balls can be used to simply implement the fitting according to the present invention. 
     The following definitions apply to the preferred characteristics that are used to select the club and ball for a particular golfer according to the method of the present invention: 
     a) player characteristics: 
     high clubhead speed—greater that about 80 miles per hour 
     medium clubhead speed—greater that about 60 to about 80 miles per hour 
     low clubhead speed—less than about 60 miles per hour 
     b) club characteristics: 
     club loft—angle between the vertical plane and the face of the club when the shaft is in the vertical plane 
     A shaft flex—Senior flex as determined by weight and shaft deflection 
     R shaft flex—Regular flex as determined by weight and shaft deflection 
     S shaft flex—Stiff flex as determined by weight and shaft deflection 
     XS shaft flex—Extra Stiff flex as determined by weight and shaft deflection 
     c) ball characteristics: 
     normal ball weight—1.58 to 1.62 oz. 
     light ball weight—1.54 to 1.58 oz. 
     high ball spin—greater than about 3500 revolutions per minute when hit by a True Temper machine under USGA standards 
     medium ball spin—greater than about 3200-3500 revolutions per minute when hit by a True Temper machine under USGA standards 
     low ball spin—less than about 3200 revolutions per minute when hit by 
     a True Temper machine under USGA standards 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a flow chart of the steps involved with fitting a player with a golf club and ball according to the method of the present invention. 
     FIG. 2 is a chart correlating club characteristics against golfer swing speed. 
     FIG. 3 is a chart correlating golf ball characteristics against swing speed. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As stated above, the present invention is directed to a simple and accurate method of fitting a player to a golf club and golf ball. Unlike more complex methods, the present invention utilizes only a few key variables out of the many available to match a player to a particular club and a particular ball in a manner that optimizes driving performance for that player. 
     In the most preferred embodiment of this invention, the following five variables are selected for use in the fitting method: clubhead speed, club loft angle, club shaft flex, golf ball weight, and golf ball spin. Thus, in the fitting method according to the present invention, only one variable is specific to the player, only two variables are specific to the golf club, and only two variables are specific to the golf ball. Thus, the method is greatly simplified over prior art methods and accurately fits the golfer. 
     The following table shows typical launch conditions for low, medium and high swing speed players versus the optimum conditions for driving performance. It is also shown that significant advances can be obtained by properly fitting a golfer to equipment based on a swing speed measurement. 
     
       
         
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
             
             
               
                   
                   
               
               
                   
                 Typical 
                 Optimum 
                 Increase in 
               
             
          
           
               
                   
                 Launch 
                   
                 Launch 
                   
                 Drive 
               
               
                 Swing 
                 Angle 
                 Spin Rate 
                 Angle 
                 Spin Rate 
                 Distance 
               
               
                 Speed 
                 (degrees) 
                 (rpm) 
                 (degrees) 
                 (rpm) 
                 (yards) 
               
               
                   
               
               
                 Low 
                 14-16 
                 2800-3200 
                 25-32 
                 2900-3300 
                 13-15 
               
               
                 Medium 
                 10-14 
                 3300-3500 
                 22-28 
                 2600-2900 
                 12-13 
               
               
                 High 
                  6-10 
                 3200-3500 
                 15-22 
                 2400-2700 
                 13-16 
               
               
                   
               
             
          
         
       
     
     Since a change in launch conditions can significantly increase driving distance, it is advantageous to measure a player&#39;s playing characteristic and select club and ball properties to assist the player&#39;s game. 
     Referring to FIG. 1, the method of the present invention is generally as follows. First, a measurement of the golfer&#39;s swing characteristic is made. In the most preferred embodiment, the golfer&#39;s clubhead speed is taken. Based on the players clubhead speed, the golfer is fitted to the golf club having the proper club characteristics based upon a predetermined relationship between the selected club characteristics and the swing characteristic. Most preferably, the club having the proper loft angle and shaft flex is selected using a direct linear relationship between these club characteristics and the player&#39;s clubhead speed using, for example, the chart in FIG.  2 . As shown by FIG. 2, the lofts and shaft flexes can be selected by first classifying the golfer into a high, medium or low swing speed using the definitions above or by using a direct relation to the swing speed, preferably within the boundaries set forth in FIG.  2 . Then, a golf ball is selected based upon a predetermined relationship between the selected golf ball characteristics and the swing characteristic. Most preferably, a ball is selected from a plurality of balls using a direct linear relationship between the ball characteristics and the swing characteristic, for example utilizing the chart set forth in FIG. 3 a golf ball can be selected using a linear relationship between golf ball weight and spin to the player&#39;s clubhead speed. The ball can be one of a plurality have a particular weight and/or spin as shown in FIG. 3 or can be classified as regular or low weight and high, medium or low spin as set forth by the definitions above. 
     The golfer&#39;s clubhead speed can be determined using any available device. Preferably, a device such as the Mini-Pro 100 Golf Swing Analyzer, the Pro V Golf Swing Analyzer or the Pro III Golf Swing Analyzer available from GolfTek, 0201 1 st  street, Lewiston, Id. 83501; the DeadSolid Golf Simulator from DeadSolid Golf, 1192 Sathers Dr., Pittston, Pa. 18640; or the Double Eagle 2000 from Par T Golf, 7310 Smoke Ranch Rd., Suite H, Las Vegas, Nev. 89128 is used to measure the clubhead speed at impact during a golfer&#39;s swing. More particularly, the golfer&#39;s swing speed is measured using a golf club having a length between 43½ to 46 inches. Most preferably, the golfer&#39;s clubhead speed is measured using a club of 44 inches long. The swing speed can then be classified as high, medium or low as set forth by the definitions above. 
     After the golfer&#39;s clubhead speed has been determined, the proper golf club is selected using the predetermined relationship between the club loft angle and the golfer&#39;s clubhead speed such as the linear relation set forth in FIG.  2 . Preferably, the loft is selected based on the natural loft, i.e., the loft of the wood measured by the angle between the face of the wood, measured at ½ the face height, and the sole of the wood less ninety degrees. The loft of a wood club is measured differently than an iron. Thus, if the present invention is being used to fit an iron, the loft is calculated by measuring the angle between the shaft bore or hosel to the club face. Determining the clubhead loft woods and irons is well know in the art and clearly set forth in Ralph Maltby&#39;s  Golf Club Design, Fitting, Alteration and Repair,  2 nd  edition, pg. 310-324. Generally though, the present invention is directed to fitting a golfer to a driver which generally come in different lofts. Preferably, the clubs are a preselected set of the same driver, e.g., the Titleist Titanium 975D drivers, which come in lofts of 5.5, 6.5, 7.5, 8.5, 9.5, 10.5 and 11.5 degrees. The lofts that are selected will depend on different parameters such as the clubhead size and location of the center of gravity. Generally, the larger the clubhead the less loft is required for a specific hitter because of the increase in dynamic loft. Therefore, the lofts set forth in FIG. 2 are merely representative of the actual set of lofts that may be selected by someone of ordinary skill in the art. 
     Thus, in the manner of carrying out the present invention set forth above, the golfer&#39;s swing speed can be measured and classified as high, medium and low and the appropriate clubhead loft determined based on the preselected loft for the swing speed. In the most preferred embodiment, the golf club loft is selected from a plurality of lofts based on a linear relationship between the golfer&#39;s swing speed and the clubhead loft as shown in FIG. 2 for example. The ranges set forth by the two linear boundaries of the fitting parameters are linear fits of golf club characteristics to golfer characteristics and there are many different direct relations that can be chosen based on the manufacturers desires. As discussed above, different manufacturers will have different sized club heads, different locations for the center of gravity, etc., which will all change the launch condition of a golf ball. 
     Then the golf club shaft is selected using a predetermined relationship between the shaft flex and the golfer&#39;s swing speed such as the linear relationship set forth in FIG.  2 . Preferably, the shaft flex is selected from a group that can comprise of L, A, R, S and XS as defined above. Preferably, the shaft flex is selected based on the deflection and weight of the shaft. Determining the shaft flex is well know in the art and clearly set forth in Ralph Maltby&#39;s  Golf Club Design, Fitting, Alteration and Repair,  2 nd  edition, pg. 481-494. Generally though, the present invention is directed to fitting a golfer to a driver which generally come in different flexes as set forth by the shaft manufacturer. For example, the following table identifies different shaft flex properties that can be followed. 
     
       
         
               
               
               
               
               
               
             
           
               
                   
                   
               
               
                   
                   
                 Length 
                   
                 Frequency 
                 Weight 
               
               
                   
                 Material 
                 (inches) 
                 Label 
                 CPM 
                 (gms) 
               
               
                   
                   
               
             
             
               
                   
                 Steel 
                 43 
                 Senior 
                 235 
                   
               
               
                   
                 Steel 
                 43 
                 Regular 
                 250 
                 120.5 
               
               
                   
                 Steel 
                 43 
                 Stiff 
                 260 
                 121.0 
               
               
                   
                 Steel 
                 43 
                 X-Stiff 
                 273 
                 124.0 
               
               
                   
                 Graphite 
                 43 
                 Regular 
                 270 
                  92.0 
               
               
                   
                 Graphite 
                 43 
                 Stiff 
                 276 
                  93.0 
               
               
                   
                 Graphite 
                 43 
                 X-Stiff 
                 290 
                  93.0 
               
               
                   
                   
               
             
          
         
       
     
     Then the golf ball weight is selected using a predetermined relationship between the golf ball weight and the golfer&#39;s swing speed such as the linear relationship set forth in FIG.  3 . Preferably, the golf ball is selected from low weight balls or regular weight balls as defined above. However, the ball weight can also have a linear relationship with the swing speed directly by providing a plurality of predetermined weights for golf balls such as those set forth in FIG.  3 . Generally though, the present invention is directed to fitting a golfer to a ball which generally come in different weights as set forth by the ball manufacturer 
     Then the golf ball spin is selected using a predetermined relationship between the golf ball spin and the golfer&#39;s swing speed such as the direct relationship set forth in FIG.  3 . Preferably, the golf ball is selected from low spin balls, medium spin balls or high spin balls as defined above and as shown in FIG.  3 . However, the ball spin can also have a linear relationship with the swing speed directly by providing a plurality of predetermined spin rate balls and matching them to particular swing speeds as shown by the upper and lower boundaries set forth in FIG.  3 . Generally though, the present invention is directed to fitting a golfer to a ball which generally comes with different spin rates as set forth by the ball manufacturer and then these are matched to particular swing speed players. 
     EXAMPLE 1 
     Consider an average handicap player (i.e., 12-18) with a measured clubhead speed of 80 miles per hour, which would characterize this golfer under the present invention as having a medium swing speed. Now referring to FIG. 2, it can be seen that such a golfer should be matched with a club having a loft angle between 9° and 15 ° and more preferably to a driver having a loft of about 12°. Moreover, the golfer should be fitted to either a R or S shaft flex to obtain optimum driving performance. Most preferably, the golfer would be fitted to the R shaft flex using FIG.  2 . Then, this golfer should be matched to a normal weight golf ball having a spin rate as set forth in FIG.  3 . More particularly, the golfer can be fitted to a ball having a weight of about 1.58 ounces and a spin rate of about 3000 when hit by a True Temper machine under USGA standards. However, it should be noted that for different golf club constructions and different golf ball constructions, these recommended lofts, flexes, ball weights and ball spin rates may vary, as discussed above. 
     EXAMPLE 2 
     Now consider a senior golfer whose measured clubhead speed is 55 miles per hour, which is a low clubhead speed under the present invention. Referring to FIG. 2, it can be seen that such a golfer should be matched to a driver with a loft angle between 12° and 18° and either an A or R shaft flex to achieve maximum driving distance. Preferably, the golfer is matched to a 15° driver with a flex as shown by FIG.  2 . Then, referring to FIG. 3, the golfer should be matched to a golf ball having a low weight and high spin. More specifically, as shown in FIG. 3, the golfer should use a low weight ball of about 1.56 oz. And have a ball with a spin rate of greater than 3500 rpm when hit with a True Temper machine according to USGA standards. 
     Although the present invention can be utilized by golfers of any skill level, the most preferred embodiment set forth in detail herein is most appropriate for medium to high handicap golfers. Furthermore, it will be understood that the claims are intended to cover all changes and modifications of the preferred embodiment of the invention, herein chosen for the purpose of illustration, which do not constitute departures from the spirit and scope of the invention.