Abstract:
Every amateur golfer wishes to improve their game. Doing so is usually achieved through significant practice and the hit-and-miss search for the right golf club. Accordingly to embodiments of the invention golf clubs imparting increased driving range through an overall increase in the mass of the golf club are presented. Additional aspects of the invention relate to achieving this without imparting a corresponding reduction in the swing velocity as well as providing for the addition of the mass a manner that reduces the tendency for the golfers swing to change, and allows for adjustment to address their natural tendency to hook or slice. As such the additional mass added to a driver may, according to embodiments of the invention, be compensated by the adjustment in the balance of the golf club and allowing for the additional mass to be added non-uniformly to the golf club head.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This patent application claims the benefit of U.S. Provisional Patent Application U.S. 61/452,196 filed Mar. 14, 2011 entitled “Method and Apparatus for Increasing and Adjusting Distribution of Weight within a Golf Club Head” 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates to golf clubs and more specifically to increasing the mass and adjusting the balance of said clubs. 
       BACKGROUND OF THE INVENTION 
       [0003]    Golf is a popular game, not only in the United States, but also in many other parts of the world such as Korea, Japan, India, China, Germany, UK and South Africa. Within the last 5 years, the golf industry has seen steady growth of 5-15% annually in most regions of the world. According to a recent market study “Opportunities in the Global Golf Club Market 2004-2009” published by E-Composites, Inc., the golf club market in India and China will continue to see a growth rate of over 25% annually for the period  2010 - 2014 . The growing popularity of the game and the general affluence of golfers ensure a substantial market, which in 2010 was estimated as US $3.9 billion. 
         [0004]    The market for manufacturers of golf clubs/golf shafts is crowded with small to large corporations such as Callaway, Taylormade, Acushnet, Ping Golf and Wilson. There are more than 100 manufacturers of golf clubs and golf club shafts around the world and about 50 of these golf club/golf club shaft manufacturers are in the USA alone. The remaining suppliers are mostly based in China, Taiwan, Korea, Japan, UK, and Germany. 
         [0005]    Considering Callaway, one of the industry leaders, then in 2008 sales were divided between woods (24%), irons (27.6%), putters (9.1%), balls (20%), and other accessories (19.3%). With annual revenues of US$1,100 million in 2008 and US$950 million in 2009 woods, irons, and putters together accounted for approximately 60% of their revenue, US$1,230 million for the two years. 
         [0006]    Over the years golf club manufacturers have released hundreds of new models featuring variations in the design of many elements of the golf clubs including hosel profile, heel, top line, toe, face, back, back cavity, sole, weighting for the head alone together with introducing steel variations, titanium and carbon fiber materials for the shafts, and weight, geometry, and polymeric materials for the grip that slides onto the upper portion of the shaft. Despite the massive research and development efforts, brand profiles built upon world renowned figures over the past decades such as Tiger Woods, Jack Nicklaus, Greg Norman, Seve Ballesteros, and Fred Couples the fundamental assembly of golf clubs has not changed for a century since the Thomas Horsburgh experimented with steel shafts in the late 1890s. 
         [0007]    However, the designers of these hundreds of models, as well as the many tens of golf ball designs released over the years, do not have complete freedom in the design, shape, features, and materials of their products. Overall the design of golf clubs, golf balls and the resulting performance of these must meet the rules and regulations of the sport that are controlled by various national organizations, such as the United States Golf Association (USGA), in association with the The Royal and Ancient Golf Course at St Andrews, Scotland. 
         [0008]    Consider a golf club manufacturer wishing to market their golf clubs in the United States then they should submit to the USGA a sample of a club to be manufactured for a ruling as to whether the club conforms with the Rules or not. Further, where a club, or part of a club, is required to meet a specification within the Rules, it must be designed and manufactured with the intention of meeting that specification. 
         [0009]    With respect to clubs then the rules state it “must not be substantially different from the traditional and customary form and make”. The club must be composed of a shaft and a head and it may also have material added to the shaft to enable the player to obtain a firm hold. All parts of the club must be fixed so that the club is one unit, and it must have no external attachments. Considering golf club heads then these may incorporate mechanisms for weight adjustment and other forms of adjustability may also be permitted upon evaluation by the USGA. However, the club head must not be purposely changed by adjustment or by any other means during playing of a round of golf, and for any permissible method of adjustment it cannot be easily made by the golfer, all adjustable parts must be firmly fixed so that there is no reasonable likelihood of them working loose during a round, and all configurations of adjustment conform with the Rules. 
         [0010]    When the golf club is in its normal address position the shaft must be so aligned with the club head so that:
       (i) the projection of the straight part of the shaft on to the vertical plane through the toe and heel must diverge from the vertical by at least 10 degrees. If the overall design of the club is such that the player can effectively use the club in a vertical or close-to-vertical position, the shaft may be required to diverge from the vertical in this plane by as much as 25 degrees;   (ii) the projection of the straight part of the shaft on to the vertical plane along the intended line of play must not diverge from the vertical by more than 20 degrees forward or 10 degrees backward.       
 
         [0013]    Except for putters, all of the heel portion of the club head must lie within 0.625 inches (15.88 mm) of the plane containing the axis of the straight part of the shaft and the intended (horizontal) line of play. 
         [0014]    The club head must be generally plain in shape and all its parts must be rigid, structural in nature and functional. The club head or its parts must not be designed to resemble any other object. It is not practicable to define plain in shape precisely and comprehensively. However, features which are deemed to be in breach of this general requirement for all and are therefore not permitted include, but are not limited to:
       holes through the face or head (some exceptions may be made for putters and cavity back irons);   features that are for the purpose of meeting dimensional specifications;   features that extend into or ahead of the face or extend significantly above the top line of the head;   furrows in or runners on the head that extend into the face; and   optical or electronic devices.       
 
         [0020]    For club heads on woods and irons these inadmissible features additionally include:
       cavities in the outline of the heel and/or toe that can be viewed from above;   severe or multiple cavities in the outline of the back that can be viewed from above;   transparent material added to the head with the intention of rendering conforming a feature that is not otherwise permitted; and   features that extend beyond the outline of the head when viewed from above.       
 
         [0025]    Additionally, golf club heads must meet specific requirements in terms of dimensions, volume and moment of inertia. Considering woods then the dimensional requirements, which must be met when the golf club is in a 60 degree lie angle, are that:
       the distance from heel to toe is greater than the distance from face to back;   the distance from heel to toe is not greater than 5 inches (127 mm); and   the distance from sole to crown is not greater than 2.8 inches (71.12 mm).       
 
         [0029]    These dimensions are measured, as shown in  FIG. 4 , on horizontal lines between vertical projections of the outermost points of the heel and the toe, and the face and the back, and on vertical lines between the horizontal projections of the outermost points of the sole and the crown. If the outermost point of the heel is not clearly defined, it is deemed to be 0.875 inches (22.23 mm) above the horizontal plane on which the club is lying. 
         [0030]    The volume of the club head must not exceed 460 cubic centimeters (28.06 cubic inches), plus a tolerance of 10 cubic centimeters (0.61 cubic inches). When the club is in a 60-degree lie angle, the moment of inertia component around the vertical axis through the club head&#39;s center of gravity must not exceed 5900 g cm (32.259 oz in), plus a test tolerance of 100 g cm (0.547 oz in). 
         [0031]    For irons, when the club head is in its normal address position, the dimensions of the head must be such that the distance from the heel to the toe is greater than the distance from the face to the back Likewise, there are dimensional rules for putters as shown in  FIG. 5  that state that when the club head is in its normal address position, the dimensions of the head must be such that:
       the distance from heel to toe is greater than the distance from face to back;   the distance from heel to toe is less than or equal to 7 inches (177.8 mm);   the distance from heel to toe of the face is at least two thirds of that from face to back;   the distance from heel to toe of the face is at least half that from heel to toe of the head; and   the distance from the sole to top of the head is less than or equal to 2.5 inches (63.5 mm).       
 
         [0037]    For traditionally shaped heads, these dimensions will be measured on horizontal lines between vertical projections of the outermost points of the heel and the toe of the head, the heel and the toe of the face, the face and the back, and on vertical lines between the horizontal projections of the outermost points of the sole and the top of the head. 
         [0038]    In respect of the striking face of the club head it must have only one striking face, except that a putter may have two such faces if their characteristics are the same, and they are opposite each other. In general the face of the club must be hard and rigid and must not impart significantly more or less spin to the ball than a standard steel face, although some exceptions may be made for putters. Except for such markings as listed below, the club face must be smooth and must not have any degree of concavity, and shall have a surface roughness within the area where impact is intended (the “impact area”) must not exceed that of decorative sandblasting, or of fine milling. The whole of the impact area must be of the same material (exceptions may be made for club heads made of wood). If a club head has grooves in the impact area they must meet the following specifications:
       grooves must be straight and parallel, have a plain, symmetrical cross-section and have sides which do not converge, and have width, spacing and cross-section that is consistent throughout the impact area;   the width (W) of each groove must not exceed 0.035 inches (0.9 mm);   the distance between edges of adjacent grooves (S) must not be less than three times the width of the grooves, and not less than 0.075 inches (1.905 mm);   the depth of each groove must not exceed 0.020 inches (0.508 mm);   for clubs other than driving clubs, the cross-sectional area (A) of a groove divided by the groove pitch (W+S) must not exceed 0.0030 square inches per inch (0.0762 mm2/mm); and   grooves must not have sharp edges or raised lips.       
 
         [0045]    If a club head has punch marks then they must meet the following specifications:
       the maximum dimension of any punch mark must not exceed 0.075 inches (1.905 mm);   the distance between adjacent punch marks (or between punch marks and grooves) must not be less than 0.168 inches (4.27 mm), measured from center to center;   the depth of any punch mark must not exceed 0.040 inches (1.02 mm); and   punch marks must not have sharp edges or raised lips.       
 
         [0050]    The center of the impact area of the club head, unless the club head is wood with an impact area made of a material of hardness less than metal, may be indicated by a design within the boundary of a square whose sides are 0.375 inches (9.53 mm) in length. Such a design must not unduly influence the movement of the ball on top of which decorative markings are permitted outside the impact area. 
         [0051]    Accordingly, a designer seeking to design a golf club and/or golf club head that improves an aspect of play for a golfer, such as driving range, must comply with all the above features and others that have not been reproduced here. They must also consider the design of the golf ball itself as it is the combination of the two in conjunction with the golfer that determines ultimately the performance achieved. 
         [0052]    Considering the golf ball then like the golf club it must not be substantially different from the traditional and customary form and make. The weight of the ball must not be greater than 1.620 ounces avoirdupois (45.93 gm), and the diameter of the ball must not be less than 1.680 inches (42.67 mm) at a temperature of 23±1° C. The golf ball must not be designed, manufactured or intentionally modified to have properties which differ from those of a spherically symmetrical ball. Further, the golf ball shall not have an initial velocity that exceeds the specified limit when measured on standard test apparatus approved by the USGA. Likewise the combined carry and roll of the golf ball, when tested on apparatus approved by the USGA, must not exceed the maximum distance specified when tested under conditions set forth in the Overall Distance Standard for golf balls. 
         [0053]    If that was not enough, these rules are subjected to ongoing amendment and revision. As of 2011, these established that the initial velocity shall not be greater than 250 feet (75 m) per second, with a tolerance of +2%, and that the overall distance standard shall not cover an average distance in carry and roll exceeding 280 yards (84 m), with a tolerance of +6%. 
         [0054]    Accordingly, the rules for both golf clubs and golf balls establish a design space within which designers operate in establishing every year the new designs that are marketed with promises of improved performance for the average golfer. These improvements may include, for example, the size of the sweet spot, the spin imparted to the golf ball, and the distance they can attain with their tee-shot. In recent years significant attention has been given to swing weight and counter-balance. The former is a measure of the total club head feel, and is used in order to achieve continuity amongst clubs for golfer and the latter is a measure of the location of the balance point of a golf club between the head and the grip. 
         [0055]    Considering swing weight then low lofted irons start off lightest in weight, for example a 3-iron head may weigh 240 g, and because they have longer shafts give the feeling of high weight to the golfer due to the leverage effect of this longer shaft. The higher the iron number the heavier the club head, for example a pitching wedge may weigh 290 g, because their shorter shafts require a heavier club head in order to give the same relative feel for the golfer. Accordingly, golf club designers have provided golfers with means to adjust the weight of the golf club therefore over a small range in order to adjust the weight and thereby the feel to the golfer. Amongst these techniques are adding multiple weights into a chamber in the golf club head such as taught by Nygren in U.S. Pat. No. 4,076,254 entitled “Golf Club with Low Density and High Inertia Head”, depicted in  FIG. 1 , and adding different weights into the sole of the club head as taught by Chen in U.S. Patent Application 2003/0,162,608 entitled “Structure of a Golf Club Head”, depicted in  FIG. 2 . Likewise Duclos in U.S. Pat. No. 5,176,383 teaches to adding a weight within the body of a golf club head rather than at the back of the golf club, as depicted in  FIG. 3 . 
         [0056]    Beach et al in U.S. Patent Application 2002/0,160,854 entitled “High Inertia Golf Club Head”, depicted in  FIG. 4 , teaches to adding weights into the base of the golf club head to adjust the inertia of the golf club head about an axis parallel to the ground. Beach also teaches that golfers prefer a driver golf club to have a total mass less than 250 grams, more preferably a total mass less than 230 grams and most preferably a mass less than 210 grams. Beach teaching that a lighter club head being preferred because it reduces the swing weight of the golf club but has less performance weight available to increase the moment of inertia of the club head. 
         [0057]    Beach teaches that the structural members of the golf club head, i.e. the outer shell and the strike plate, typically have mass approximately 60%-90% of the total mass of the club head. The remaining 40%-10%, that constitutes the performance mass, is in the weight plugs of the invention taught by Beach. Typically within the prior art relating to weight golf club manufacturers have searched for ways to best distribute the performance weight so as to improve club head performance and have attempted to position most of the performance mass along the perimeter of the club head so as to increase the inertia of the club head. 
         [0058]    Such perimeter weighting increases the inertia of the club head about the vertical axis and tends to make the club head more resistant to twisting during off-center hits but represents an inefficient use of the performance mass. Exceptions to the general trend of heel/toe weighting include Tseng in U.S. Pat. No. 6,620,053 entitled “Golf Club” teaches to inserting a weight into the shaft of the golf club rather than adjusting the weight of the club head itself, depicted in  FIG. 5   
         [0059]    However, if we consider a golf ball as a simple spherical object, without dimples and other aerodynamic effects such as drag and wind are neglected, then the trajectory calculation is really very simple. For any given time (t) the distance traveled (x component) is given by Equation (1): 
         [0000]        x ( t )=( V   o  cos( m )) t   (1)
 
         [0000]    and the height (y component) at any given time (t) is given by Equation (2): 
         [0000]        y ( t )=( V   o  sin( m ))−( gt   2 /2)  (2)
 
         [0000]    where V o  is the initial velocity of the golf ball, g is gravitational acceleration 9.8 m/s/s, and m is the launch angle in radians. 
         [0060]    However, this simplistic trajectory is impacted by other factors such as the Magnus effect that defines the lift generated by a spinning dimpled golf ball in flight. When a lofted club strikes the ball properly, the ball will tend to travel or roll up the clubface before it is launched. This causes the ball to anti-clockwise spin at a rate governed by the speed, loft and surface friction of the club head face at impact. Typical ball spin-rates are:
       3,600 rpm—hit with a 10° driver (8° launch angle) at a velocity of 134 mph   7,200 rpm—hit with a 5 iron (23° launch angle) at a velocity of 105 mph   10,800 rpm—hit with a 9 iron (45° launch angle) at a velocity of 90 mph       
 
         [0064]    The Magnus effect can be estimated by Equation (3): 
         [0000]        F   L ( dvr   4   a   v 2 di   2 )(2 r )  (3)
 
         [0000]    where d is the density of air, v is the velocity of the golf ball, r is the golf ball radius, and a v  is the angular velocity in radians per second. Additionally, we have to consider air drag and wind force, these being given by Equations (4) and 5 below: 
         [0000]        F   w   =−C   w   V   w   (4)
 
         [0000]        F   d   =−C   d   V   x   −C   d   V   x   −C   d   V   z   (5)
 
         [0000]    where C d,w  are the drag coefficients, V x,y,z  are the components of the velocity in the x, y, and z directions, and V w  is the wind velocity. 
         [0065]    As such it is evident that the flight of the golf ball initially is determined by the velocity imparted in the strike from the golf club, coupled to with the lift angle and spin before loss of momentum and reduced spin rate from air resistance cause the golf ball to start dropping. As spin rate is additionally dependent upon loft angle of the golf club and its velocity at impact the initial velocity of the golf ball is critical to a golfer achieving distance with their strokes. 
         [0066]    When the clubface of the golf club collides with the golf ball its total contact time is only approximately 0.0005 seconds but the peak force applied to the ball can be as high as 4000 pounds that actually compresses the golf ball at impact. The initial velocity of the golf ball after impact may be approximated by Equation (6) below: 
         [0000]        V   ball =( V   club  Coeff rest )/(1+( m   ball   /m   club ))  (6)
 
         [0000]    where V club  is the velocity of golf club head at impact, Coeff rest  is the coefficient of restitution that accounts for the momentum loss and the fraction of the energy into a collision that a “collision” returns, m ball  is the mass of the ball, and m club  is the mass of the club. Including the loft of the clubface results in Equation (7) wherein: 
         [0000]        V   ball   loft =cos(loft) 2  sin(90−loft) V   ball   (7)
 
         [0000]    where loft is the loft angle of the club. 
         [0067]    The coefficient of restitution for a typical golf ball is 1.67 and 45 g. Accordingly, for the golfer they have two ways to influence the initial velocity of the golf ball, and hence the distance for a specific club. The first is by increasing V club , the velocity of the golf club at impact, and secondly through using a heavier club, thereby increasing m club . However, generally for an individual swinging a heavier club leads to a reduction in the velocity of the club. 
         [0068]    However, as the mass of the club head increases there is an increased tendency for the club head to twist the golf club in the golfer&#39;s hands such that the golf club face strikes the ball at an angle. Hitting the ball with what is known as an “open club-face” and a club-path from out to in will cause the ball to spin from left to right. The ball&#39;s flight will then curve to the right or “Slice.” Conversely, hitting the ball with a “closed club-face” and a club-path from in to out will cause the ball to spin from right to left. The ball&#39;s flight will then curve to the left or “Hook”. 
         [0069]    Equation (6) is derived from the considerations of force, kinetic energy and momentum of the golf club. As the swing progresses, the golfer applies more and more force to the golf club head causing it to accelerate and so increase its speed. Accordingly, when a golfer swings for a long drive, the goal is to accelerate the club head so that it impacts the ball at just the right point, going in just the right direction, and moving as quickly as possible. To do so, the golfer exerts force with his or her arms on the shaft of the golf club, which in turn exerts force on the golf club head. This situation may be approximated as a double pendulum wherein the arms, pivoting at the shoulders, roughly behave as a first pendulum, and the hands, grip, and shaft, pivoting at the wrists, behave as a second pendulum attached at the end of the first. For a well-timed drive, at the moment of impact the upper pendulum, i.e. the arms, is swinging very rapidly about its pivot point, and, at the same moment, the club is swinging very rapidly around its pivot point. 
         [0070]    During this rapid motion of the swing the golfer must also control the orientation of the golf club with the intention of hitting the golf club squarely, to avoid hook and slice, and vertical position to avoid what are known as thick shots, the club is hitting the lower portion of the ball primarily, and thin shots, primarily hitting the upper portion of the ball. Overall therefore golf is a very challenging game, mainly due to control of the club while swinging and at impact. Accordingly, if you can swing the golf club a shorter distance and/or at a slower speed you will have more control and a better result, one of the biggest challenges for recreational golfers is trying to increase club head speed and still maintain control, yet golf club manufacturers are telling golfers that higher club head speed is required for a better game. To achieve this requires the golfer to have increased flexibility, so the swing arc is longer, increased strength so they can accelerate the club head faster, which is almost impossible to achieve for “regular” players who represent the vast majority of golfers globally. 
         [0071]    Accordingly, with a heavier club a golfer can utilize a shorter swing arc and/or a shorter shaft, giving further control, with a lower club head speed and achieve a significant length drive. This is something “regular” golfers will find relatively easy to do as opposed to fundamentally adjusting their physique, coordination etc. 
         [0072]    Accordingly, it would be beneficial to increase the mass of the golf club without imparting a corresponding reduction in the swing velocity thereby allowing the golfer to achieve an increased distance in their game. It would be further beneficial for the additional mass to be added in a manner that reduces the tendency for the golfers swing to adjust resulting in increased hook or slice. As such the additional mass added to a driver may, according to embodiments of the invention, be compensated by the adjustment in the balance of the golf club and allowing for the additional mass to be added non-uniformly to the golf club head. 
       SUMMARY OF THE INVENTION 
       [0073]    It is an object of the present invention to 
         [0074]    In accordance with an embodiment of the invention there is provided a device comprising providing a golf club head, providing at least one predetermined region of a plurality of regions within the golf club head, and selectively adding to the at least one predetermined region a predetermined mass of a material. 
         [0075]    In accordance with an embodiment of the invention there is provided a method comprising:
   providing a golf club head having a predetermined weight, a first predetermined distribution of mass between a front strike face of the golf club head and a rear face of the golf club head, and a second predetermined distribution of mass between a first side of the golf club head positioned closer relative to a user when in use and a second side golf club head positioned away from the user when in use;   providing a shaft for attachment to the hosel, the shaft being attached at a first distal end;   providing at the second other distal end of the shaft a first predetermined weight at a first predetermined location; and   providing at the second other distal end of the shaft a second predetermined weight at a second predetermined location.   
 
         [0080]    In accordance with an embodiment of the invention there is provided a method comprising:
   providing a first predetermined portion of a golf club head comprising at least one first recess of a plurality of first recesses;   providing a second predetermined portion of a golf club head comprising a hosel and at least one second recess of a plurality of second recesses;   providing a third predetermined portion of a golf club comprising at least a first face, the first face for mating to the first predetermined portion of the golf club head and having a third recess positioned to align with each first recess of the plurality of first recesses;   providing at least a plug of a plurality of plugs, each plug comprising a first predetermined portion having a geometry compatible to fitting into a first recess in the first predetermined portion of a golf club head and a second predetermined portion having a geometry compatible to fitting into a second recess in the second predetermined portion of a golf club head, wherein   each plug is comprised predominantly of at least a material having a density significantly higher than the materials that form each of the first and second predetermined portions of the golf club head.   
 
         [0086]    Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0087]    Embodiments of the present invention will now be described, by way of example only, with reference to the attached Figures, wherein: 
           [0088]      FIG. 1  depicts a golf weighting technique according to the prior art of Nygren in U.S. Pat. No. 4,076,254; 
           [0089]      FIG. 2  depicts a golf weighting technique according to the prior art of Chen in U.S. Patent Application 2003/0,162,608; 
           [0090]      FIG. 3  depicts a golf weighting technique according to the prior art of Duclos in U.S. Pat. No. 5,176,383; 
           [0091]      FIG. 4  depicts a golf weighting technique according to the prior art of Beach in U.S. Patent Application 2002/0,160,854; 
           [0092]      FIG. 5  depicts a golf weighting technique according to the prior art of Tseng in U.S. Pat. No. 6,620,053; 
           [0093]      FIG. 6A  depicts a golf weighting technique according to an embodiment of the invention; 
           [0094]      FIG. 6B  depicts a golf weighting technique according to an embodiment of the invention; 
           [0095]      FIG. 7  depicts a golf weighting technique according to an embodiment of the invention; 
           [0096]      FIG. 8  depicts a golf weighting technique according to an embodiment of the invention; 
           [0097]      FIG. 9  depicts a golf weighting technique according to an embodiment of the invention; 
           [0098]      FIG. 10  depicts a golf weighting technique according to an embodiment of the invention; 
           [0099]      FIG. 11  depicts a golf weighting technique according to an embodiment of the invention; 
           [0100]      FIG. 12  depicts a technique for providing a controlled hard surface to a golf club body formed from a high density metal; 
           [0101]      FIG. 13  depicts a technique for adjusting a golfer&#39;s feel for a golf club; and 
           [0102]      FIG. 14  depicts a technique for adjusting a golfer&#39;s feel for a golf club. 
       
    
    
     DETAILED DESCRIPTION 
       [0103]    The present invention is directed to golf clubs and more specifically to increasing the mass and adjusting the balance of said clubs. 
         [0104]    Referring to  FIG. 6A  there is shown a golf putter  600  according to an embodiment of the invention. Once assembled the golf putter  600  would appear to be composed of heel  610 B, toe  610 A, and body  640  connected to the shaft  660  via hosel  655 . Disposed upon the visible exterior surfaces of body  640  are shaped recess  635 , top sight line  645  and rear sight lines  650 . Each of the heel  610 B and toe  610 A being attached to the body  640  via bolt  605  that screws into threaded recess  630 . 
         [0105]    Disposed within the faces of each of heel  610 B and toe  610  are three first recesses  615 . Likewise with the faces of body  640  abutting the heel  610 B and toe  610 A are three second recesses  625 . Accordingly up to three slugs  620  can be inserted into the three second recesses  625  per face of the body  640  before the heel  610 B and toe  610 A are attached. It would therefore be evident that adding the slugs  620  to each side symmetrically increases the weight of the golf putter  600  whereas adding the slugs  620  in different combinations on either end of the golf putter  600  allows the weight to be increased but also distributed asymmetrically between heel  610 B and toe  610 A. 
         [0106]    Considering a golf putter  600 A formed from stainless steel then the density of the body  640 , heel  610 B and toe  610 A would be approximately 8 g/cc, c.f. iron at 7.87 g/cc. For example 304 stainless steel has a density of 8.03 g/cc. Examples of materials for increasing the mass of these elements individually, in combination, or in combination with the slugs  620  are listed below in Table 1. 
         [0000]    
       
         
               
             
               
               
               
             
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Density of Potential Weighting Materials for Golf Clubs 
               
             
          
           
               
                   
                   
                 Relative to 304 
               
               
                 Material 
                 Density g/cc 
                 Stainless Steel 
               
               
                   
               
             
          
           
               
                 Tin 
                 7.300 
                 0.91 
               
               
                 Copper 
                 8.940 
                 1.11 
               
               
                 Silver 
                 10.490 
                 1.31 
               
               
                 Lead 
                 11.340 
                 1.41 
               
               
                 Mercury 
                 13.593 
                 1.69 
               
               
                 Tungsten carbide 
                 15.800 
                 1.97 
               
               
                 Tungsten 
                 19.300 
                 2.40 
               
               
                 Platinum 
                 21.400 
                 2.67 
               
               
                   
               
             
          
         
       
     
         [0107]    Optionally, each of heel  610 B and  610 A may be formed from a material of increased density along with the slugs  620  or they may be formed from different materials to each other and/or the slugs  620 . Accordingly if each of the first and second recesses  615  and  625  are filled with a slug of tungsten, rather than air, the increased mass of the golf putter  600  is 3.55 g per slug  620 . If all 6 slugs as shown are employed then the increased mass is 21.g. Making the slugs  620  2 cm long the increase in mass of the golf club is 42.6 g. Increasing the diameter of the slugs  620  to 1 cm results in an increase in mass of the golf putter  600  by up to 170 g. As such in terms of asymmetry the heel  610 B in this instance may be imbalanced by up to 85 g against a golf putter  600   g  without slugs  620  bringing the center of gravity of the golf putter  600  closer to the shaft  660 . Alternatively the toe  610 A may be imbalanced by up to 85 g against a golf putter  600   g  without slugs  620  moving the center of gravity of the golf putter  600  further away from the shaft  660 . 
         [0108]    Whilst the approach shown in  FIG. 6A  was for a golf putter  600  the approach may be applied equally to a golf driver. However, as the golf driver is larger more slugs  620  may be inserted. Such a structure being shown by insert  690  in  FIG. 6A  wherein a driver is configured with 11 slug inserts for each interface between heel and toe and central body. It would be apparent to one skilled in the art that the pattern may for example be a row of 4 along the bottom of the club and a further 3 to the upper rear thereby removing any recesses closer to the face of the club. 
         [0109]    Now referring to  FIG. 6B  there is depicted an alternate embodiment of the invention for weighting a golf club comprising a body  6150  and shell  6100 . Referring initially to first view  6000 A an elevation of the body  6150  is shown on the back surface  6300  away from the strike face  6250 . Disposed within the back surface  6300  of the body  6150  are a plurality of threaded holes  6050  that are disposed to the heel, closer to the hosel  6350 , centre, and toe, farther from the hosel  6350 . The centre threaded holes  6050  being set into a pattern going from below an axis of the centre of gravity of the unweighted golf club to above the axis. 
         [0110]    Referring to second view  6000 B the body  6150  is shown in plan elevation with plug  6200  inserted into the threaded holes  6050 . Accordingly it would be evident to one skilled in the art that the weighting of the golf club can be increased by adding plugs  6200  to the body  6150  and that the distribution of the weight may be adjusted either to the heel/toe of the golf club or above/below the centre of gravity of the unweighted golf club therein adjusting the location of this centre of gravity to for the user. Referring to third view  6000 C the body  6150  is shown assembled with sell  6100  so that the golf club has an improved aerodynamic profile, aesthetic appearance, and compliance to golf rules. It would also be evident that by making the threaded holes  6050  with a small thread, such as M3 or 6-40 UNC for example, that the pitch of the threaded holes  6050  may be set small allowing multiple locations to be provided in the back surface  6300  even if all are not populated with larger plugs  6200 . Alternatively the outer diameter of the plug may be close to the diameter of the threaded inserts allowing a higher density of plugs  6200  to be added to the golf club. Alternatively plugs of various dimensions and/or materials may be provided to provide adjustments in the incremental weight added to the club through each plug added. 
         [0111]    Referring to  FIG. 7  there is depicted an alternate embodiment of the invention for weighting a metal golf club  700  wherein the weighting is applied to a hollow shell body  710  that has disposed within a chamber  720 . Access to the chamber being obtained through an orifice  730  that is sealed with plug  740 . Considering materials for golf club heads such as aluminum (melting point 660° C.), 304 stainless steel (1400° C.), and 316 stainless steel (melting point 1450° C.) then it would be evident to one skilled in the art that there is significant flexibility in selection of solder. Referring to Tables 2 and 3 the properties of common materials within solders and the resultant solders are summarized. 
         [0000]    
       
         
               
             
               
               
               
             
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 Properties of Materials in Common Solders 
               
             
          
           
               
                 Material 
                 Melting Point (° C.) 
                 Density (g/cm-3) 
               
               
                   
               
             
          
           
               
                 Silver (Ag) 
                 1765 
                 10.49 
               
               
                 Zinc (Zn) 
                 419.5 
                  7.14 
               
               
                 Tin (Sn) 
                 231.9 
                  5.79 (grey) 
               
               
                 Lead (Pb) 
                 327.5 
                 11.34 
               
               
                 Bismuth (Bi) 
                 271.5 
                  9.78 
               
               
                 Antimony (Sb) 
                 630.6 
                  6.70 
               
               
                 Indium 
                 156.6 
                  7.31 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
             
               
               
               
             
               
               
               
             
           
               
                 TABLE 3 
               
             
             
               
                   
               
               
                 Properties of Some Common Solders 
               
             
          
           
               
                 Material 
                 Melting Point (° C.) 
                 Density (g/cm-3) 
               
               
                   
               
             
          
           
               
                 Pb98Sn2 
                 316 
                 11.5 
               
               
                 Pb75Sn25 
                 183 
                 9.95 
               
               
                 Sn50Pb50 
                 183 
                 8.56 
               
               
                 Bi52Pb32Sn14 
                 96 
                 9.64 
               
               
                 In50Sn50 
                 118 
                 6.54 
               
               
                 Sn50Zn50 
                 199 
                 6.19 
               
               
                   
               
             
          
         
       
     
         [0112]    Some solders, such as In50Sn50 have good wetting to ceramics allowing their use in conjunction with ceramic golf club bodies, such as putters and irons. Sn50Zn50 has good wetting to aluminum. As such the body of the golf club  710  may be heated or unheated and molten solder added into the chamber  720  to add weight to the club. 
         [0113]    Referring to  FIG. 8  an alternate embodiment is depicted in side elevation  800  and plan view  850  respectively. As shown in side elevation  800  a golf club head  810  has three access points  820 ,  830  and  840  on the rear face. Referring to plan view  850  it can be seen that first access point  820  is coupled to first chamber  870 , second access point  830  is coupled to second chamber  860 , and third access point  840  is coupled to third chamber  850 . Accordingly, not only can the weight of the golf club be increased significantly but the distribution of that weight can be adjusted between the centre and towards the heel/toe. 
         [0114]    Now referring to  FIG. 9  there is depicted wherein a golf club  910  has been patterned with multiple recesses  920  through  995  respectively that may be filled with low melting point alloy, i.e. a solder. Accordingly the multiple recesses  920  through  955  allow for a more complex adjustment in the distribution of weight and the total weight added. Optionally, a single base cover may be attached over the bottom of the club once the multiple recesses have been accessed for the addition of the low melting point alloy. Such a cover providing a cosmetic finish but also providing a smooth lower surface for improved aerodynamics. 
         [0115]    Referring to  FIG. 10  an alternate embodiment is presented wherein the main body of the golf club head  1070  has a recess, not shown for clarity formed within it. In the bottom of the recess are three threaded inserts, not shown for clarity, that accept first to third screws  1010 ,  1040  and  1060  respectively. Fitting into the recess are first insert  1020 , second insert  1030 , and third insert  1050 . Accordingly if first to third inserts  1020 ,  1030 , and  1050  are formed from a fibre reinforced polymer (FRP) then they will have a density of approximately 1.6-2.0 gcm −3  thereby offering a golf club head  1070  weight essentially determined by the body of the golf club head. However, if first to third inserts  1020 ,  1030 , and  1050  are formed from tungsten then these will have a density of 19.3 gcm −3  thereby increasing the weight of the golf club head  1070 . It would also be apparent to one skilled in the art that one, two or all three inserts may be changed from FRP to tungsten providing differing weights overall and differing weight distributions. Likewise third insert  1050  may be replaced with one from copper, density 8.94 gcm −3 , whilst first and second inserts  1020  and  1030  are replaced with tungsten. In this manner the weight is increased but a distribution towards the heel is achieved. Alternatively each insert may be replaced by two inserts such that a thinner FRP insert and a thinner metallic insert are combined to provide weights that are increased but not as heavy as complete replacement of the insert(s). 
         [0116]    Referring to  FIG. 11  there is shown another embodiment of a golf club head  1100  according to an embodiment of the invention. Within the preceding embodiments weight has been added to a lower weight club head. In  FIG. 11  this is reversed wherein the golf club head  1100  is initially formed at the maximum mass, for example through the use of a thick tungsten sole plate. Subsequently, material is then selectively removed through post-processing, for example, milling such that material is removed from predetermined areas  1110  to  1130  respectively. Such post-processing reduces the weight and also allows the weight distribution to be modified front to back or heel to toe. It would be apparent that complex or simple patterns of material removal might be considered without departing from the scope of the invention. 
         [0117]    Referring to  FIG. 12  an alternate structure for a golf club head  1200  is depicted comprising a base element  1210 , body element  1220  and core  1230 . Body element  1220  for example may be formed from a glass/carbon/basalt fiber FRP or a ceramic such as alumina, having a typical density of 4 gcm −3 , or tungsten carbide, density 15.8 gcm −3 . Core  1230  may be formed from a material such as tungsten that is then selectively post-processed, such as by machining to remove material. The core  1230  being bonded to the body element  1220 . Formed upon the face of golf club head  1200  is an impact area  1240 , formed for example by the selective deposition of tungsten, diamond or other material to form the impact surface. 
         [0118]    Alternatively, core  1230  may be formed from materials with varying densities such as FRP, aluminum, and tungsten to provide a series of increasing weights for the overall golf club head  1220 . The body element  1220  may also be formed from a progressive sequence of materials. In the case that the body element  1220  for example is formed from tungsten then the impact area  1240  may be formed from tungsten carbide through the carbonization of tungsten. 
         [0119]    As discussed supra the “feel” of a golf club to a golfer can be adjusted through the position of the balance point. In the embodiments presented supra the focus has been to increased golf club weight. Considering golf club  1300  then this is achieved together with an adjustment in “feel” or swing weight through the provisioning of a counter-balancing weight in the grip portion  1300 B of the club. Accordingly, there is shown in the hosel-shaft region  1300 A a first in-shaft weight structure and in the grip portion  1300 B a second in-shaft weight structure. For simplicity these are depicted as being the same. Accordingly a hollow shaft  1310  has a tapered inner channel, not identified for clarity, receiving a bar-like weight  1320 . The weight  1320 , being shaped to mate with the inner channel. The hollow shaft  1310  further has a threaded inner periphery  1315  defined at its thin end  1313 , and the threaded intermediate section  1333  of the structure  1330  is engaged with the threaded inner periphery  1315  in such a way that its annular stop  1331  abuts the thin end  1313  of the shaft  1310  and its boss  1335  fits in the recess  1321  of the weight  1320 . As a result, the structure  1330  is connected to the shaft  1310 . 
         [0120]    A secondary weight  1360  may be additionally received in the channel of the hollow shaft  1310 , if necessary. The secondary weight  1360  being located adjacent to an end of the weight  1320  opposed to the structure  1330 , and has a boss  1361  configured to fit in the recess  1322  of the weight  1320 . The secondary weight  1360  may further have a recess  1362  for the addition of a third weight. The hosel  1330  and the weight  1320  or weights  1320 ,  1360  may be joined to the shaft  1310  through a resin  1370 , which may also be applied to the recesses  1321 ,  1322  and the bosses  1335 ,  1361 . In this case, the hollow shaft  1310  has a vent  1314  defined therein, in order to let air into the hollow shaft  1310  to help consolidation of the resin  1370 , as well as to lead surplus resin  1370  out of the hollow shaft  1310 . 
         [0121]    Accordingly through the combination of the weight  1320  or weights  1320 ,  1360  the overall weight of the golf club  1300  can be adjusted but also the “feel” adjusted by adding more counter-balancing weight to the grip of the golf club  1300 . 
         [0122]    Referring to  FIG. 14  there is shown an alternate golf club  1400  providing increased weight, counter-balancing but with increased adjustment. Accordingly in each of the hosel attachment region  1400 A and grip region  1400 B of the golf club  1400  an adjustable weight structure is provided. As shown the shaft  1450  has disposed a first plate  1420  and a second plate  1460 . Running between first plate  1410  and second plate  1460  is lead screw  1430  that has a key recess  1410  at the end with first plate  1420 . Lead screw  1430  being free to rotate relative to first and second plates  1420  and  1460  respectively. Attached to the lead screw  1430  is weight  1440  such that rotation of the lead screw  1430  through the use of the key in key recess  1410  moves the weight vertically along the length of the lead screw  1430 . Accordingly, the weight(s) can be adjusted vertically with respect to the golf club  1400 . Optionally with a long lead screw multiple weights  1440  may be added to one or both structures. As such the golf club weight can be increased; the “feel” adjusted through counter-balancing and the golf club  1400  set to each individual gofer&#39;s preferred set-up. 
         [0123]    It would be evident that the embodiments of the invention above may be employed discretely or in combination. For example weighting the golf club head with an asymmetric weighting and counter-balancing through a weight in the grip of the golf club. 
         [0124]    The above-described embodiments of the present invention are intended to be examples only. Alterations, modifications and variations may be effected to the particular embodiments by those of skill in the art without departing from the scope of the invention, which is defined solely by the claims appended hereto.