Patent Publication Number: US-8523706-B2

Title: Golf club head having a hollow rail member

Description:
TECHNICAL FIELD 
     The present disclosure relates generally to golf equipment, and more particularly, to methods, apparatus, and systems to custom fit golf clubs. 
     BACKGROUND 
     Industrial automation can provide many challenges in producing a product. Golf clubs are a particular challenge. Mass production tends to produce things that are uniform in design, quality and reliability, very well. However, golfers are not a very uniform group. Even if two players share many physical characteristics their swing, stance and the like can be quite different from each others. When personal differences are taken into consideration with the wide variety of the physical forms of players, designing a set of golf clubs that can be easily produced and can be custom fit for a variety of players having differing swings is a challenge. 
     Club customization is an effort to fit clubs to a player&#39;s individual needs. Manufactured clubs can be reworked, and clubs can be custom built. However, even custom built clubs may lack a sufficient degree of customization to satisfy golfers desiring to improve their game. Accordingly there may be a number of issues encountered in providing highly customizable golf clubs that perform well, are durable and are easy to manufacture. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present description will be better understood from the following detailed description read in light of the accompanying drawings, wherein: 
         FIG. 1  shows an example iron-type golf club head. 
         FIG. 2  shows an iron-type golf club head having a hollow top rail with weight redistribution. 
         FIG. 3  shows the cross section detail of an exemplary hollow top rail of an iron-type golf club head having a hollow top rail member. 
         FIG. 4  shows three examples of disposing a hollow rail in an iron-type golf club head having a hollow top rail. 
         FIG. 5  is a diagram showing stress along the length of the top rail of an iron-type golf club head having a hollow top rail on hitting a golf ball. 
         FIG. 6  shows an example of a hollow top rail insert. 
         FIG. 7  shows a cross section of a constant thickness top rail. 
         FIG. 8  shows a cross section of a variable thickness top rail. 
         FIG. 9  is a diagram showing stress along a first exemplary cross-section of the top rail of an iron-type golf club head having a hollow top rail on hitting a golf ball. 
         FIG. 10  is a diagram showing stress along a second exemplary cross section of the top rail of an iron-type golf club head having a hollow top rail on hitting a golf ball. 
         FIG. 11  shows an example of a balloon hollow top rail. 
         FIG. 12  is a diagram of an iron-type golf club head having a hollow rail with weight redistribution and including alternative sectional construction, to allow weight redistribution. 
         FIG. 13  is a flow diagram of a method for constructing a golf club. 
     
    
    
     Like reference numerals are used to designate like parts in the accompanying drawings. 
     DESCRIPTION 
     The detailed description provided below, in connection with the appended drawings, is intended as a description of the present examples, and is not intended to represent the only forms in which the present example may be constructed or utilized. The description sets forth the functions of the example and the sequence of steps for constructing and operating the example. However, the same or equivalent functions and sequences may be accomplished by different examples. 
     The examples below describe a golf club having a hollow rail member constructed with unique shaping to provide improved strength, while reducing weight, in particular when the hollow rail member is disposed on the top rail. The weight removed from in the rail member may be redistributed to change club performance. 
     Club strength may be improved in various ways, including selection of material for the hollow rail member, form of cross sectional profile, form of longitudinal profile, wall thickness, varying wall thickness, construction techniques, and the like. 
     Although the present examples are described and illustrated herein as being implemented in a system of fitting iron-type golf clubs, the system described is provided as an example and not a limitation. As those skilled in the art will appreciate, the present examples are suitable for application in a variety of different types of golf club systems including drivers, woods, putters, wedges, and the like. 
       FIG. 1  shows an example iron-type golf club head  100 . The club head  100  is shown in a front view  102  and an end view  104 . The club head  100  may be illustrative of golf club features in general as this iron-type golf club head includes a hosel  106 , a face  108 , a club body  110  and a toe  112 . In clubs, the face  108  is typically reinforced by the club body  110  to provide a satisfactorily strong striking surface. However, it may be desirable to improve club strength and performance by redistributing body  110  weight. 
       FIG. 2  shows an iron-type golf club head having a hollow top rail member  202  allowing weight redistribution  200 . This design may allow weight in the club to be freed up while maintaining strength and structural integrity of the club. The freed up weight may then be redistributed to other areas of the club which may increase the performance (i.e., increase moment of inertia, lower center of gravity, etc.) of the club, typically by moving the weight, or a portion thereof, to a lower position. Alternatively, for a lighter club, the weight, or a portion thereof need not be added back. For example weight may be moved, or redistributed to, any of the sole, toe or heel areas. 
     The hollow top rail member (or alternatively, top rail, hollow rail member tubular section, hollow top rail insert, specially constructed strengthening insert, hollow rail insert with strengthening section, or hollow rail with a reinforcing bulge)  202  may include a long axis  204  that substantially describes the overall length  208  of the hollow top rail member  202 . In alternate examples it is understood that the “top” rail member  202  described below need not necessarily be disposed in a top position, as other positions may be possible. Thus the top position in which this specially constructed strengthening insert  122  is described is but an example of its use, or positioning. A strengthening section  210  may be provided over a portion of the long axis  204 , or alternatively over the entire long axis  204 . As shown the hollow top rail member  202  may be part of a reinforcing rail structure disposed about the perimeter on the back side  212  of the club face. One or more hollow rail members (e.g., the hollow top rail member  202 ) may be disposed along any portion of the perimeter  214  of the club  200 . The hollow top rail member, need not be disposed in a “top” position to free up club weight, but may be disposed in any suitable position on the club. The hollow top rail member  202  may be integral to the club head  200 , or a separate piece disposed in the club body. If constructed as a separate piece, the hollow top rail member  202  may extend through the body of the club head  200  to form a part of the club face, or it may be disposed on the back side  212  of the club face replacing a part of the rail section, and leaving the face as a unitary single piece. However, extending the hollow top rail member  202  through the face of the club head  200  tends to allow more material to be removed for more weight removal. 
     The hollow top rail member  202  may create discretionary weight by reducing the mass of the top rail  216  of the club head  200 . This reduction in weight may be accomplished by hollowing out the top rail  216  and changing the shape in various dimensions to maintain or improve strength while allowing a weight reduction to be made. The change in shape of the top rail  216  does not simply remove weight. It also provides a strengthened structure (e.g., via the hollow top rail member  202 ) in compensation for materials removed as the change in shape tends to evenly distribute stress levels when a ball is hit. 
     In alternative examples, the hollow top rail member  202  could be made of a material with a higher strength than the club body  222 . This allows for thinner walls with lighter weight while maintaining durability. This in turn would provide even more discretionary weight for redistribution to other areas of the club, such as the toe  218 . 
     It may be desirable to remove the weight from the top rail  216  and position it lower on the club head  200  at an alternative location. For example more weight could be added to the toe  218 , which produces a lower center of mass for the club head  200 . Alternatively weight could be added to the hosel  220 , or any other portion of the club head  200  desired. 
       FIG. 3  shows the cross section detail of an exemplary hollow top rail of an iron-type golf club head  300  having a hollow top rail member  202 . This view shows an exemplary cross sectional view  302  of the hollow top rail member  202 . As shown, the top rail  202  is substantially hollow along its length. Along the length, a bulge  304  may be provided, typically in a central location or equivalent as desired to compensate for stress or otherwise strengthen the club head  300  during ball impact. The bulge  304  may extend downward, or alternatively in another direction, such as protruding in a rearward direction from the club head, or may point in any suitable direction. 
     The hollow top rail member  202  may include as part of its cross sectional area a stress dissipating portion  306 , which may be known to be an area where stress is concentrated while hitting the ball. Providing an appropriate cross section  302 , bulge  304 , rail thickness, variation in rail thickness, and the like in this part can allow for providing a structure in the hollow top rail member  202  that allows strength to be maintained or improved, while allowing weight to be removed. 
     The face portion  308  of the cross sectional area  302  can form part of the club face  310 , or may be coupled to the back side  312  of the club face  310  without forming a part of the club face  310 . As such the unitary face can serve to couple and absorb stress from striking the ball, to the stress dissipating area  306  of the hollow top rail member  202 . 
       FIG. 4  shows three examples of disposing a hollow top rail member  202  in an iron-type golf club, to form clubs having a hollow top rail member  402 ,  404 ,  406 . However, other configurations, or examples, utilizing the techniques described in this document may be constructed. 
     In the first exemplary configuration of a club head  402  the hollow top rail member  408  is constructed as an integral part of the club head. The club head  402  is shown in a view from the rear, to show the cavity  410  disposed in the hollow rail  408 . Disposing a cavity  410  in the club head  402  may be accomplished by suitable casting, and machining or other equivalent techniques. A suitable alternative technique may include investment casting. The insertion of a ceramic core during the wax injection phase of investment type of casting can allow the creation of the cavity  410 . One or more entry and exit holes may be provided so that the ceramic particles can be sand blasted out of the casting. These entry or exit holes can then be welded shut and suitable finishing provided to provide a smooth appearance. 
     The second exemplary configuration  404  and third exemplary configuration  406  may utilize a welded in or otherwise coupled tubular structure as a hollow top rail member  202 . As shown in view  202  this process includes casting the club without a top rail  416 , and leaving a let-out portion  418  of the top rail to later accept the hollow top rail member  202 . A specially constructed part, or hollow top rail member  202  may be welded into the opening  418  and the welds ground and polished to provide a smooth surface. The formed hollow top rail member  202  may be investment cast, may be created by hydro forming, or by equivalent methods. 
     In the second exemplary configuration  404 , the hollow top rail member  202  is included as part of the club face  422 . This construction can allow for more weight savings as the face portion of the hollow top rail member  424  protrudes through to the face  422 , and makes up part of the club face  422  typically thinning the assembled face thickness of the face portion of the hollow top rail member  424  due to the hollowed out cavity  410 . 
     In the third exemplary configuration  406 , the hollow top rail member  202  is disposed against the back side  420  of the club face  422 . The hollow top rail member  202  is disposed against a ledge or thinned portion of the face  420 . This configuration may not have as great a weight savings due to the cavity  410  typically being smaller. But the configuration  406  may allow for an integral face  422  to be provided. 
     The hollow top rail member  202  may be made from any suitably strong material that may be integrated into the assembly, including steel, aluminum, titanium, carbon composite materials, fiberglass and the like. The hollow top rail member or tube to club connection may also be assembled in alternative examples by interlocking or by snapping in or rotating in the part. 
       FIG. 5  is a diagram showing stress along the length of the top rail of an iron-type golf club head having a hollow top rail in response to the club head striking a golf ball. Of particular interest is the relation of top rail design to the stress levels. The stress levels are results from dynamic finite element analysis which simulate a golf club impacting a golf ball  502 . Near the center of the longitudinal axis of the top rail an area of higher stress is indicated  504  by close spaced lines, with a decreasing stress level indicated by an increase in line spacing. This area of higher stress  504  in the hollow top rail member may call for incorporation of a strengthening section having a bulge or other suitable shape to counteract the stress, and strengthen the club. 
     In addition, the walls of such a part could consist of varying thickness. The stress distribution during impact indicates that the stress is higher in the middle of the top rail and lower towards the ends. Therefore the tube walls could be made thinner on the ends. This creates additional discretionary weight that may be eliminated or moved to another location. 
       FIG. 6  shows an example of a hollow top rail member  202 . As shown the hollow top rail member  202  may include a strengthening section, or region  602  that may be provided in various shapes  604 ,  606 ,  608 ,  610 . The external shapes may be formed as a bulge  604 , a corner  606 , a step  608 , an exponential taper  610  or the like. The strengthening section may extend over a portion or all of the length  208  along the longitudinal axis  204  of the hollow top rail member  202 . Alternatively the strengthening section  602  need not be positioned substantially centered along the length  208 . The strengthening section  602  may be offset from center along the length  208 , to provide an asymmetrical configuration. The interior cavity  612  of the hollow top rail member  202  may provide a varying thickness produced from an interior curvature differing from the outside curvature (variable wall thickness), a thickness tracking the curvature of the strengthening section (constant wall thickness), or the cavity width may be of a constant width  614  (as shown), creating a variable wall thickness. The variable wall thickness may provide additional support in the strengthening section. The strengthening section  602  may protrude in various directions, such as directly back (as show), or in equivalent directions such as up, down, or in any suitable position. The hollow top-rail member  202  may be constructed of any suitable material such as metal, non-metals, or the like. 
       FIG. 7  shows a cross section of a constant thickness top rail  702 . As shown the wall thickness  704  is substantially constant and tends to follow the curvature of the outside strengthening section  602  of the top rail over the length of the strengthening section  602 . In this example the cavity width  706  tends to vary. Also in alternative examples wall thicknesses  708 ,  704  need not be identical even in the constant thickness model. 
       FIG. 8  shows a cross section of a variable thickness top rail  802 . As can be seen the width of the hollowed portion  806  is substantially constant with the outside wall curvature in the strengthening section  602  changing so that a variety of wall thicknesses  804 ,  810  may be formed. Also in alternative examples wall thicknesses  808   804  need not be similar. 
       FIGS. 9 and 10  show finite element analysis simulations which compare two examples of hollow top rail construction and illustrate the effect on stress in the club from changing the shape of the top rail. The figures show moments in time when the stress levels on the club head are at their highest. 
       FIG. 9  is a diagram showing stress along a first exemplary cross section of the top rail of an iron-type club head having a hollow top rail  902  in response to the iron-type club head striking a golf ball  904 . As can be seen in this diagram, the stress dissipating portion of the cross section  906  is somewhat small and pointed. As a result, stress may be transmitted  912  from striking a ball  904 , through a face portion  908  of the hollow top rail  902  (or alternatively in the case where a hollow top rail member does not protrude through the club face the stress may be transferred first through the face of the club, then to the face portion  908 ). The transmitted stress  912  is then seen to be directed and concentrated in an area  910  in a stress dissipating portion of the cross section  906 . Since the stress is ultimately transferred here this area may be advantageously strengthened in this area, as previously described. 
       FIG. 10  is a diagram showing stress along a second exemplary cross section of the top rail of an iron-type club head having a hollow top rail  1001  on hitting a golf ball  1004 . Note that the area of high stress shown concentrated in the previous example ( 910  of  FIG. 9 ) tends to be more spread out  1010 . Also note the reduced stress levels as shown in  FIG. 10  versus  FIG. 9 . These examples show the exemplary top rail of  FIG. 10  having a greater area (provided by an exemplary balloon construction) which tends to be stronger than the exemplary top rail of  FIG. 9 , and tends to show through the shading that the geometric design has a noticeable impact on club durability. In this example of  FIG. 10 , the stress may be reduced by increasing the area of the stress dissipating portion of the cross section  1006 , typically by increasing the hollowed out area cross section, or ballooning the structure. 
       FIG. 11  shows an example of a balloon hollow top rail, generally shown as  1102 . A first example hollow top rail  1102  includes an exemplary 0.020 inch thick hollow wall  1104 , and a second example of the hollow top rail  1104  may include an exemplary 0.030 inch thick hollow wall  1104 . Both hollow top rails variations  1102  are formed in a “balloon” cross sectional configuration  1106  to relieve stress in the part. Equivalent cross sectional configurations may be substituted having equivalent wall thicknesses  1104 . 
       FIG. 12  is a diagram of an iron-type golf club head having a hollow rail ( 202  of  FIG. 2 , or alternatively a hollow top rail disposed in a position other than “top”) with weight redistribution and including alternative sectional construction to allow weight redistribution  1202 . In this example, weight removed from the club head may be added to the heel  1204 . Alternatively, other sections of the club  1206 ,  1208 ,  1210 ,  1214 , may be constructed as described for the hollow top rail so further weight may be redistributed (removed/added to other areas such as the toe  1204 , the top rail  1208 , the toe rail  1206 , the sole rail  1214 , the heel rail  1218 , the hosel weight  1216  or the like. Fitting methods which may allow the assembly of interchangeable components, includes welding, epoxying, snap fit, or the like to couple a hollow top rail member to the various locations described above. 
       FIG. 13  is a flow diagram of a method for constructing a golf club  1300 . At block  1302  reducing the mass of a top rail of a golf club is performed. At block  1304 , shaping a top rail back section to disperse stress on impact with a ball. In particular, the top rail back section may be elongated and may include a protrusion which may extend perpendicularly from the long axis of the top rail. Also, shaping the top rail back section may be performed to cause a constant rail thickness or alternatively a variable rail thickness. 
     At block  1306 , redistributing or adding discretionary weight to an area to improve club performance may be performed. In particular, the discretionary weight is added to the toe, the hosel, or the like. Further, the center of gravity &amp; moment of inertia tuning may be made by a combination of two or more connected or disconnected weights being arranged in differing configurations. 
     Those skilled in the art will realize that the process sequences described above may be equivalently performed in any order to achieve a desired result. Also, sub-processes may typically be omitted as desired without taking away from the overall functionality of the processes described above.