Abstract:
A shaft structure with a configurable bending, weight, torque and moment-of-inertia profile is provided for golf clubs, fishing rods, and the like. The shaft structure employs an innovative inner and outer shaft structure. The golfer, in practice, configures the profile of a golf shaft by choosing from a plurality of different inner shaft structures each having a unique bending, weight, moment-of-inertia and torque profile. The inner shaft is securely fastened within the outer shaft. The combination of the inner shaft with the outer shaft results in an advantageous bending, weight, torque and moment-of-inertia profile. The golfer can, at any time and very easily, change the profile of the golf shaft according to their physical, course and weather conditions for any given day.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates to shafts for golf clubs, fishing rods and the like and more particularly where the overall bending, weight, torque and moment-of-inertia profiles of these devices can be configured by the user to match their physical abilities as well as course and weather conditions. 
       BACKGROUND OF THE INVENTION 
       [0002]    Golf shafts are typically manufactured with a predetermined bending, weight, torque and moment-of-inertia profile. The “bending profile” of a golf shaft refers to a distinct flex pattern that a conventional golf shaft exhibits when subjected to a force. The flex pattern is typically measured as the amount of deflection the shaft experiences when the shaft is positioned horizontally and subjected to a constant force. 
         [0003]    Previous knowledge of golf shaft dynamics resulted in a general understanding that the overall stiffness of a golf shaft played a role in the performance of a golf club. However, it has been discovered that the overall bending profile of the shaft has much more to do with the performance of a golf club than merely its overall stiffness. The bending profile directly contributes to ball launch angle and spin, both of which can directly affect shot distance and accuracy. Additionally, the bending profile can influence club-head reaction and orientation before the clubface makes contact with the ball. Presently, golf shafts are mass produced with a predefined and fixed bending profile without regard for a golfer&#39;s individual swing mechanics. Typically, these parameters are designed in an attempt to accommodate a vast multitude of golfers. 
         [0004]    Prevailing weather conditions can also affect optimum ball flight. For example, on a windy day, a golfer might choose to reconfigure their shaft for a bending profile that promotes a lower penetrating ball flight which reduces the affects of the wind. Conversely, on a day with little or no wind, a golfer may choose to configure the bending profile to promote a higher launch angle. 
         [0005]    Course conditions can also dictate shot choice and performance. On a course with narrow fairways a golfer may choose a stiffer shaft so as to improve accuracy whereas a course that has wider fairways but is longer would dictate a less stiffer shaft so as to maximize distance. 
         [0006]    The overall weight of a golf shaft plays a crucial part in the performance of the golf club. The lighter the golf shaft the more head speed a golfer can generate which translates into more distance. However, some golfers find that a lighter shaft does not allow them to “feel” the position of the head through the swing and as result there is a loss of control. Therefore, some golfers prefer a heavier golf shaft. The weight of the golf shaft is a function of a golfer&#39;s preferences and can enhance performance. 
         [0007]    The torque of a golf shaft directly relates to the performance of a golf shaft. Torque is generally defined as torsional resistance. As such, torque also relates to the amount and type of feedback the golfer receives when the golf ball is struck. A golf ball which strikes the toe or the heel of the golf club causes the golf club head to rotate about its center of gravity. This action causes the golf ball to drastically alter course from the intended target line. Additionally, off center hits generate vibrational energy that is then transmitted via the golf shaft to the golfer&#39;s hands resulting in a “stinging” sensation. Golf shafts with a relatively high torque rating can cause the golf club head to rotate more thereby less energy is translated into vibrational energy. As a result less vibrational energy is transmitted to the golfer&#39;s hands. Conversely, a golf shaft that has a low torque rating necessarily causes the golf club head to rotate less thereby more energy is converted to vibrational energy which is then transmitted to the golfer&#39;s hands. The torque of the golf shaft is a function of a golfer&#39;s preferences and can enhance performance. 
         [0008]    The moment-of-inertia of a golf club can be directly attributable to the “feel” of the golf club and with that the performance by increasing the confidence level of the golfer. In lieu of configuring a moment-of-inertia the golfer may choose to configure the swing-weight of the golf club as indicated by a swing-weight machine. 
         [0009]    Various proposals to provide variable stiffness for a golf club shaft (or even a fishing pole) have previously been made that involve using a hollow shaft charged with a gas or liquid fluid that can be pressurized and by mechanical devices such as rods, jackscrews and the like. Increasing the fluid pressure in the shaft increases the shaft stiffness. Increasing the length of the rod increases the tension and hence shaft stiffness. 
         [0010]    Such pressurizable shafts are illustrated, for example, by Menzies U.S. Pat. No. 1,831,255, Sears U.S. Pat. No. 2,432,450, Busch U.S. Pat. No. 3,037,775, Burrough U.S. Pat. No. 4,800,668 (a fishing rod), Simmons U.S. Pat. No. 5,316,300, Koch et al. U.S. Pat. No. 5,540,625, Painter U.S. Pat. No. 5,632,693 and Qualizza U.S. Pat. No. 7,226,365. 
         [0011]    So far as is known, these variable stiffness, hollow shaft structures of the prior art do not address changing a shaft&#39;s bending profile but rather have defined a device which indiscriminately promotes a stiffness change across the entire shaft and never addresses the ability to adjust the bending characteristics of the golf shaft. Additionally, the prior art does not address being able to change a shaft&#39;s overall weight, torque or moment-of-inertia. 
       SUMMARY OF THE INVENTION 
       [0012]    In order for a golf club to be effective and ultimately configured for a golfer by the golfer without requiring the golfer to have intimate knowledge or club-building skills, the present invention provides for a device that can be easily changed to accommodate the golfer&#39;s abilities, weather and course condition for any given day. The device can also be adapted for use in existing golf shafts. 
         [0013]    The present invention overcomes the inability of prior art shafts to create a unique bending, weight, torque and moment-of-inertia profile. The present invention also overcomes the inability of the prior art to be able to effect a change in the performance of the golf shaft by providing a device which does not serve to present an axial stress force to a conventional shaft but rather provides a device which combines a shaft-in-a-shaft structure where an outer shaft is complimented by an inner, configurable bending, weight, torque and moment-of-inertia profile shaft. The inner shaft structure is placed within an outer shaft structure, in effect forming a shaft within a shaft. The bending, weight, torque and moment-of-inertia profile of the overall shaft structure is born form the compounded action of both the inner and outer shaft structures. Given this arrangement, new shafts as well as existing shaft&#39;s bending, weight, torque and moment-of-inertia profiles can be readily changed that will match the golfer&#39;s abilities so as to maximize both shot accuracy and distance. 
         [0014]    The inner shaft structure can easily be exchanged with another thereby in effect changing the overall shaft bending, weight, torque and moment-of-inertia profile. Each unique inner shaft structure has a unique bending, weight, weight distribution and torque rating. The configurable profile shaft does not require special tools or skills to affect the configuration of the bending, weight, moment-of-inertia or torque profile of an overall shaft structure. 
         [0015]    By choosing different inner shaft structures with each having their own bending, weight, weight distribution and torque parameters, an overall shaft structure can be built by the golfer to accommodate their individual physical abilities as well as to match course and weather conditions for an individual day. In practice, the golfer extracts the inner shaft structure from the outer shaft structure, chooses a new inner shaft structure and then securely places the inner shaft structure back within the outer shaft structure. 
         [0016]    An object of the present invention is to provide an overall shaft structure which allows a golfer to change the bending profile of a golf shaft to suit their needs, physical abilities, course and weather conditions. 
         [0017]    Another object of the present invention is to provide an overall shaft structure which allows a golfer to change the overall weight of a golf shaft to suit their needs, physical abilities, course and weather conditions. 
         [0018]    Yet another object of the present invention is to provide an overall shaft structure which allows a golfer to change the moment-of-inertia of the shaft structure and hence “feel” of a golf club to suit their preferences. 
         [0019]    Another object of the present invention is to provide an overall shaft structure which allows a golfer to change the torque of a golf shaft to suit their preferences and physical needs. 
         [0020]    Another object of the present invention is to provide a shaft structure that has a selectable bending profile. Hence, a single assembled shaft structure can replace many different combinations and permutations of golf shafts, golf clubs, fishing poles and manufacturing procedures and can avoid the need for large inventories of golf clubs with golf club shafts pre-set to different stiffness values, thereby effecting a saving of what would otherwise be an expenditure of substantial amounts of money. 
         [0021]    Another object of the present invention is to provide a shaft structure which allows a golfer to customize the bending profile of each shaft of an entire set of clubs, or of fishing poles, according to his ability or wishes without being dependent upon the shaft stiffness, weight, torque and moment-of-inertia that happens as a result from shaft manufacturing procedures as in the prior art. 
         [0022]    Yet another object of the current invention is to provide a device which can be easily adapted to an existing shaft structure so as to provide a golfer the ability to adjust the bending profile of their existing golf shaft. 
         [0023]    Yet another object of the current invention is to provide a device which can be easily adapted to an existing shaft structure so as to provide a golfer the ability to adjust the moment-of-inertia profile of their existing golf shaft to match that of their favorite club. Therefore, all the clubs in the bag can have the same “feel” as their favorite club. 
         [0024]    Another object of the present invention is to provide a fishing rod structure which allows a fisherman to configure the bending profile a fishing rod. 
         [0025]    Another object of the current invention is to provide for a device that can easily replicate the physical and hence performance characteristics of any given shaft on the market. If a golfer chooses they or a manufacturer of the current invention can interrogate other golf shafts on the market in order to gather the variable bending, weight, moment-of-inertia and torque characteristics of the shaft. In this manner the resultant behavioral characteristics can be duplicated by the present invention. As such the present invention can replicate the performance of virtually any other shaft on the market. 
         [0026]    Other and further objects, aims, features, advantages, applications, embodiments and the like regarding the present invention will be apparent to those skilled in the art from the present specification, attached drawings, and appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]    The invention may be understood by reference to the following description taken in conjunction with the accompanying drawings, in which, like reference numerals identify like elements, and in which: 
           [0028]      FIG. 1  illustrates a perspective view of one embodiment of a golf club which incorporates a shaft structure of the present invention; 
           [0029]      FIG. 2  illustrates a view of the proximal end of inner shaft structure of the shaft structure of  FIG. 1 ; 
           [0030]      FIG. 3  illustrates a more detailed view of the inner shaft structure of the shaft structure of  FIG. 1 ; 
           [0031]      FIG. 4  illustrates a cross-sectional view of the connection apparatus of the coupling section of the shaft structure shown in  FIG. 3 ; 
           [0032]      FIG. 5  view of the distal end of inner shaft structure of the shaft structure of  FIG. 1 ; 
           [0033]      FIG. 6  illustrates an alternative embodiment of the current invention that reveals segmented inner shaft structure; 
           [0034]      FIG. 7  illustrates a cross-sectional view of the segments of the shaft structure shown in  FIG. 6 ; 
           [0035]      FIG. 8  illustrates a locking mechanism of the shaft structure shown in  FIG. 6 ; 
           [0036]      FIG. 9  illustrates the nomenclature for displaying stiffness, weight and torque for a segment for the shaft structure shown in  FIG. 6 ; 
           [0037]      FIG. 10  illustrates an alternative embodiment of the current invention using separate components for the bending profile, weight, weight distribution and torque; 
           [0038]      FIG. 11  illustrates yet another embodiment of the current invention whereby the inner and outer shaft structures are in full contact in effect forming one shaft with out the need for spacers; 
           [0039]      FIG. 12  illustrates another alternative embodiment of the current invention that utilizes a thin layer of fluid to transmit the bending profile of the outer shaft structure to the inner shaft structure. 
       
    
    
     DETAILED DESCRIPTION 
       [0040]      FIG. 1  reveals an illustrative golf club  10  that incorporates an embodiment of an overall shaft structure  12  of the present invention. In the preferred embodiment, overall shaft structure  12  includes an outer shaft structure  18  and an inner shaft structure  16 . Both the outer shaft structure  18  and the inner shaft structure  16  are defined by a proximal and distal end. In the matter of a golf club the proximal end is accompanied by a conventional golf grip  25  whereas the distal end is accompanied by a conventional golf club-head  30 . Shaft structure  12  is defined as having an overall unique bending, weight, moment-of-inertia and torque profile. The overall moment-of-inertia of shaft structure  12  is defined by the unique distribution of weight of both the outer shaft structure  18  and the inner shaft structure  16 . The bending, weight, weight distribution and torque profile of the outer shaft structure  18  remains constant and fixed. The inner shaft structure  16  exhibits a bending, weight, weight distribution and torque profile as well but can be exchanged with a different inner shaft structure  16  that exhibits a different bending, weight, weight distribution and torque profile thereby in effect allowing the golfer to modify the profile of the shaft structure  12  to their preference. Both outer shaft structure  18  and inner shaft structure  16  can be fashioned from graphite, ferrous and non-ferrous metals, plastics and the like and need not be of the same material. Those skilled in that art will recognize that a vast multitude and combinations of materials may be used for both the outer shaft structure  18  and the inner shaft structure  16  and that the use of alternate materials does not deviate from the scope or the spirit of the present invention. 
         [0041]    In the present invention both the outer shaft structure  18  and inner shaft structure  16  exhibit a bending profile that is defined by a unique pattern of stiffness that traverses the inner shaft structure  16  from the proximal end to the distal end longitudinally. The pattern of stiffness allows for a unique bending pattern for shaft structure  12  that is born from the convoluted bending patterns of the inner shaft structure  16  and outer shaft structure  18  which are in mechanical cooperation. The outer shaft structure  18  is defined by a stiffness pattern that may be constant from proximal to distal end or in other embodiments it may change. In the preferred embodiment the inner shaft structure  16  has a stiffness pattern that changes from proximal to distal end. In another embodiment and with an existing golf shaft  12  the outer shaft structure  18  stiffness varies and defines the bending pattern. In this mode the inner shaft structure  16  bending profile would be profiled as a constant stiffness from proximal to distal end. As a result the overall bending profile would remain constant but the stiffness would increase. Those skilled in the art will recognize that a multitude of combinations of bending patterns can occur for the inner shaft structure, outer shaft structure or both and that these various combinations do not deviate from the spirit or scope of the present invention. This pattern defines, among other things, the kick-point of the overall shaft structure  12 . As is well known in the industry the kick-point of the overall shaft structure  12  is a major determinant in golf ball trajectory. For instance, a high kick-point will cause a low golf ball trajectory while a low kick-point will cause a high golf ball trajectory. A mid kick-point will cause a mid golf ball trajectory. 
         [0042]    In the present invention the overall weight of the shaft structure  12  is defined by the weight of the outer shaft structure  18  in additive combination with the weight of the inner shaft structure  16 . The weight of the shaft structure  12  plays an important role in the performance of a golf club  10  whereas a lighter overall shaft structure  12  weight allows the golfer to swing the golf club  10  faster thereby increasing club-head  30  speed which translates into more distance. Although a heavier shaft structure  12  and hence a heavier golf club  10  allows for less club-head  30  speed there is a benefit that relates to accuracy derived from being able to better control the golf club  10  due to the lower swing speed. Additionally, as the golfer becomes older he or she can regain swing-speed by making the overall shaft structure  12  lighter by exchanging the inner shaft structure  16  with one that has less weight thereby reducing the overall weight of the golf club  10 . 
         [0043]    In the present invention the weight profile or rather the distribution of weight longitudinally is defined by the distribution of weight of the outer shaft structure  18  in additive combination with the distribution of weight of the inner shaft structure  16 . The weight distribution of the outer shaft structure  18  may be constant from proximal to distal end or in other embodiments it may change. The weight distribution of the inner shaft structure  16  is unique and can be distributed so as to effect the overall moment-of-inertia of the golf club  10 . In another embodiment and with an existing golf shaft  12  the outer shaft structure  18  weight distribution varies. In this mode the inner shaft structure  16  weight distribution would be constant from proximal to distal end. As a result the overall weight of the shaft structure  12  would increase but not the distribution of weight. Those skilled in the art will recognize that a multitude of combinations of weight distributions can occur for the inner shaft structure, outer shaft structure or both and that these various distributions do not deviate from the spirit or scope of the present invention. In more generic terms the moment-of-inertia relates to the “feel” of the golf club  10  such as it is described by a golfer as the golf club  10  being “heavy” or “light”. A proxy for moment-of-inertia is swing-weight of the golf club  10  as is well known in the industry. In general terms the moment-of-inertia will increase when more weight is placed toward the distal end of the golf club  10  and will decrease as more weight is placed toward the proximal end. In this regard weight distribution within the inner shaft structure  16  can effect the moment-of-inertia. 
         [0044]    The torque of a golf shaft  12  directly relates to the performance of a golf shaft  12 . The torque profile of the outer shaft structure  18  is constant from proximal to distal end. The torque profile of the inner shaft structure  16  is unique and can be distributed so as to affect the torque profile of the overall shaft  12 . As is well known torque relates to the amount and type of feedback the golfer receives when the golf ball is struck. Additionally, a golf ball which strikes the toe or the heel of the golf club  10  causes the golf club head  30  to rotate about its center of gravity. Off center hits also tend to generate vibrational energy that is then transmitted via the golf shaft  12  to the golfers hands resulting in a “stinging” sensation. Golf shafts  12  with a relatively high torque rating can cause the golf club head  30  to rotate more. As a result less vibrational energy is transmitted to the golfer&#39;s hands. Conversely, a golf shaft  12  that has a low torque rating necessarily causes the golf club head  30  to rotate less in which more energy is converted to vibrational energy and on to the golfer&#39;s hands. The torque of the golf shaft  12  is a function of a golfer&#39;s preference and can enhance performance. 
         [0045]    In the preferred embodiment and referring to  FIG. 2 , inner shaft structure  16  includes select bending, weight, weight distribution and torque parameters and further includes a proximal and distal end. Inner shaft structure  16  is held in place at the proximal end by threaded cap  19 . Threaded cap  19  cooperatively engages threaded cup  21  of outer shaft structure  18  which is firmly affixed to the inner diameter of outer shaft structure  18  by conventional means. The proximal end of inner shaft structure  16  includes disk  25 . Disk  25  includes longitudinal lands  3  and  5  which cooperatively engage slots  7  and  9  respectively of threaded cup  21 . The cooperative engagement of lands  3  and  5  with slots  7  and  9  serve to anchor the torque as it is transmitted from the golf club-head  30  to the inner shaft structure  16 . 
         [0046]    With reference to  FIG. 3  inner shaft  16  is comprised of main body  22 , spacer  15 , spacer  17 , and spacer  19 . Main body  22  is designed so as to provide a distinct bending, weight, weight distribution and torque profile. The distinct bending pattern for main body  22  is driven from the material, diameter and wall thickness. Weight is a function of density of material and wall thickness. Torque is a function of material, diameter and wall thickness. Those skilled in the art will recognize that initially the bending, weight, weight distribution and torque profile are all co-dependent upon the material, wall thickness and diameter of the main body  22  of the inner shaft structure  16 . As such the inner shaft structure  16  will be designed taking into account of the design parameters such as material type, wall thickness and diameter. Distal end of inner shaft structure  16  is comprised of coupler  26 . In another embodiment an inner shaft structure system may be designed that incorporates a plurality of inner shaft structure such that each inner shaft structure would accommodate one or more particular parameters. For instance, there may be an inner shaft structure  16  for addressing the bending profile and another inner shaft structure  16  that would address weight distribution. 
         [0047]    Spacers  15 ,  17  and  19  serve to support inner shaft structure  16  by virtue of mechanical communication with the outer shaft structure  18  at strategic locations. The number and placement of spacers  15 ,  17  and  19  are defined so as to transfer the bending pattern of the outer shaft structure  18 , when under load, to the inner shaft structure  16 . In this manner inner shaft structure  16  is then able to influence the bending profile of the overall shaft structure  12  by virtue of its configurable arrangement. Those skilled in the art will recognize that a multitude of different types and means of support and location may be provided and these alternative means and locations do not deviate from the scope or spirit of the present invention. 
         [0048]    Referring to  FIG. 4 , male coupling device  28  of coupler  26  includes platen  23  and cross member  24 . Platen  23  has a diameter that cooperates and is firmly affixed to the internal diameter of the distal end of inner shaft structure  16 . Cross member  24  includes male cross pattern which cooperates and is received by the female cross pattern of the female coupling device  29 . The diameter of the female coupling device  29  cooperates and is affixed to the inside diameter of outer shaft structure  18  by conventional means. Further, coupler  26  serves to convey the torque that is imposed by the club head  30  to inner shaft structure  16 . 
         [0049]    With further reference to  FIG. 5  outer shaft structure  18  is affixed to the inside diameter of hosel  35  of club-head  30 . Inner shaft structure  16  is placed within the outer shaft structure  18 . Upon the introduction of inner shaft structure  16  to outer shaft structure  18  the golfer will choose to rotate the inner shaft structure  16  so as to align the cross member  24  of male coupling device  28  with female coupling device  29  of coupler  26 . Once aligned the inner shaft structure  16  of the male coupling device  28  engages with female coupling device  29  thus allowing the inner shaft structure  16  to be fully seated. In this manner inner shaft structure  16  is allowed to “float” or move axially but yet still retain torque integrity generated at the club-head  30  due to the arrangement of coupler  26 . Those skilled in the art will recognize that a multitude of designs can occur for the transferring of torque from the club head  30  to the outer shaft structure  18  and then to the inner shaft structure  16  and that these various other designs do not deviate from the spirit or scope of the present invention. 
         [0050]    Female coupling device  29  receives and cooperates with male coupling device  28  to form a structurally sound mechanical detachably connection that, by design, structurally transitions, homogenously, the characteristic torque generated at the club-head  30  to the inner shaft structure  16 . Male coupling device  28  and female coupling device  29  can be fabricated from lightweight material such as carbon fiber or ultra-high-molecular weight (UHMW) plastic. 
         [0051]      FIG. 6  reveals an alternative embodiment including an outer shaft structure  18  and inner shaft structure  16  wherein inner shaft structure  16  is comprised of separate, mechanically connected sections. Each section may have a unique stiffness, weight and torque rating. Three separate sections  22 ,  23  and  24  are shown to illustrate the present invention. With respect to the inner shaft structure  16 , section  22  is typically referred to as the tip section; section  23  is often referred to as the mid section and section  24  is often referred to as the butt section. Fewer or additional sections are within the scope of the present invention. Both the outer shaft structure  18  and inner shaft structure  16  may be formed from various materials such as graphite, ferrous and non-ferrous metals, plastics and the like. Those skilled in the art will recognize that a multitude of material can be used for both the inner shaft structure  16  and outer shaft structure  18  and using other materials does deviate from the spirit or scope of the present invention. 
         [0052]    The variable bending profile of the overall shaft structure  12  includes the variable bending properties of both the inner shaft structure  16  and outer shaft structure  18  working in tandem. The overall bending profile of outer shaft  18  is substantially constant while the overall bending profile of the inner shaft structure  16  is modifiable by virtue of the stiffness contributions of each of the sections  22 ,  23  and  24 . 
         [0053]    The overall weight of shaft structure  12  includes weight of the outer shaft structure  18 , which may be substantially constant, as well as the overall configurable weight contributed by assembled sections  22 ,  23  and  24  that define the inner shaft structure  16 . 
         [0054]    The moment-of-inertia of shaft structure  12  and as well the golf club  10  itself, includes the moment-of-inertia of the outer shaft structure  18 , which is substantially constant, as well as the total configurable moment-of-inertia as contributed by the distribution of weight of assembled sections  22 ,  23  and  24  that define the inner shaft structure  16 . 
         [0055]    The overall shaft structure  12  is detachably affixed at one end of a conventional club head  30  (not detailed structurally) and at the opposite end with a circumferentially extending, conventional golf grip  25  (not detailed structurally). 
         [0056]    With reference to  FIG. 7 , the proximal end of the mid section  23  is detachably engaged with coupler  26  and with coupler  31  at the distal end of the mid section  23 . Tip section  22  may be detachably engaged at the proximal end of the tip section  24  with coupler  31  and by coupler  50  at the distal end of tip section  24 . Inner shaft structure  16  is held in place at the distal end by the cooperative engagement of coupler  50 . Those skilled in the art will recognize and appreciate that a plurality of sections as well as a plurality of different types of coupling devices can be incorporated and that such an arrangement does not deviate from the scope and the spirit of the present invention. Mechanical connection of the individual sections occurs via a quick disconnect coupler. 
         [0057]    Spacers  15 ,  17  and  19  of section  22 ,  23  and  24  respectively serve to support inner shaft structure  16  relative to outer shaft structure  18  at strategic locations. The number and placement of spacers  15 ,  17  and  19  are defined so as to transfer the distinct bending pattern of the outer shaft structure  18 , when under load, to the inner shaft structure  16 . In this manner inner shaft structure  16  is then able to influence the bending profile of the overall shaft structure  12  by virtue of its configurable arrangement. Additionally, the length of tip section  22 , mid section  23  and butt section  24  can be chosen to advantageously place the kick-point anywhere along the shaft. For instance, in addition to the stiffness chosen for mid section  23  mid section  23  can be configured to be exceptionally long with spacers  17  located near the ends of mid section  24  so that maximum bending would occur at mid shaft thereby creating a mid kick-point. 
         [0058]      FIG. 8  reveals a typical quick disconnect coupler  35 . Locking mechanism  35  including locking tab  36  cooperating with loading spring  37 . Loading spring  37  is located within channel  38 . As an example, during assembly of mid section  23  with butt section  24 , the golfer introduces the male coupling device  28  to the female coupling device  29 . Pushing down firmly causes locking tab  36  of locking mechanism  35  to retract into channel  38  thusly loading spring  37  and allowing cross member  34  to fully engage female coupling device  29 . The pushing action causes locking tab  36  of locking mechanism  35  to retract into channel  38  thus granting the ability to fully insert male cross member  34  of male coupling device  28  into female coupling device  29 . Both male coupling device  28  and female coupling device  29  become fully engaged when locking tab  36  of locking member  35  protrudes past the bottom of female coupling device  29 . At this time, locking tab  36  springs back to the initial position and the top of locking tab  36  engages the bottom of female coupling device  29  thereby creating a detachable rigid and firmly affixed structural connection. Conversely, upon disassembly, the golfer inserts special tool  50  into acceptance hole  52 . Upon activation of the tool, scrawl end  54  inserts into acceptance hole  52  and reaches locking tab  36 . Further prosecution of the scrawl end  54  inward causes locking tab  36  to retract into channel  37  thereby compressing spring device  37 . When locking tab  36  is fully retracted into channels  38  the golfer is than able to disconnect mid section  23  from butt section  24 . 
         [0059]      FIG. 9  depicts a typical mid section  23  that displays markings  70  that identify the particular characteristics of stiffness, weight and torque. The stiffness marking  72  refers to the stiffness of mid section  23  in a 200 to 300 scale with 300 being the stiffest. The weight marking  74  refers to the overall weight of the mid section  23  in grams, i.e. 30 grams. The torque marking  76  of the mid section  23  is depicts as 1.0 to 5.0 scale where 1.0 equals the lowest torque while 5.0 represents the highest torque rating of the tip section  23 . Those skilled in the art will appreciate that any marking nomenclature such as color-coding and other decipherable markings could be use in lieu of the enclosed markings and that doing so will not deviate from the teachings herein. In practice, a golfer would have a multitude of sections  22 ,  23  and  24  as spares and then would choose the sections that would best obtain the performance that they are looking for. 
         [0060]    Configuring a variable bending profile is defined by the choice and then detachable assembly of tip section  22 , mid section  23  and butt section  24 . For instance, a golfer may choose a bending profile that promotes a strong mid section  23  and butt section  24  with a weak tip section  22 . This arrangement would facilitate a low kick-point. In this manner tip section  22  would be chosen with the lowest stiffness rating as compared to mid section  23  and butt section  24 . Mid section  23  and butt section  24  would be chosen with a higher stiffness than tip section  22 . Conversely, if a golfer chooses to configure a bending profile with a mid kick-point then the golfer would choose a mid section  23  with stiffness rating that is lower than tip section  22  and butt section  24 . As well choosing a high kick-point would dictate that the golfer would choose a butt section  24  with stiffness rating that is less than the stiffness rating for tip sections  22  and mid section  23 . It should be noted that the overall stiffness as defined by the contribution of the assembled tip section  22 , mid section  23  and butt section  24  constitute a stiffness profile. 
         [0061]    Additionally, in practice, the golfer would decide upon an overall target weight of the golf shaft  12 . The golfer would then choose the weight of each section which has the required stiffness so that the total combined weight of the assembled inner shaft structure  16  in conjunction with the weight of the outer shaft structure  18  would achieve the desired target weight of the overall golf shaft  12 . 
         [0062]    In addition to choosing the correct overall weight the golfer would also choose which section  22 ,  23  or  24  would contribute the greater weight to the overall weight of the inner shaft structure  16  such that the placement of the weight would cause the moment-of-inertia to be to their liking. For instance, if a golfer chooses to decrease the moment-of-inertia they would choose a butt section  24  whose weight is greater than tip section  22  and mid section  23 . Conversely, if they choose to increase the moment-of-inertia they would necessarily choose a tip section  22  weight that is greater than mid section  23  and butt section  24  weight. 
         [0063]    In practice and when a golfer chooses to adjust the bending profile the golfer will first remove the inner shaft structure  16  by removing hex cap  19  via a hex wrench. Once removed the inner shaft structure  16  is then disassembled and either/or tip section  22 , mid section  23  or butt section  24  is replaced. The inner shaft structure  16  is then placed back within the outer shaft structure  18 . The hex cap  19  is then threaded back on and tightened. 
         [0064]    Although in the preferred embodiment three sections are shown those skilled in the art will readily recognize and appreciate that a plurality of sections can be used and in doing so will not deviate from the scope or the spirit of the present invention. Those skilled in the art would also appreciate that using a plurality of independent shaft structures would allow for a finer tuning of the overall bending profile. 
         [0065]      FIG. 10  reveals an alternative embodiment of the inner shaft structure  16 . Inner shaft structure  16  includes a single support member  84  which is used to accommodate and support spacers  72 ,  74 ,  76  and  78  as well as stiffening sleeve  82  and weights  80 . Support member  84  can be chosen to achieve a certain torque rating by virtue of the diameter and material chosen. In this embodiment, a precise bending profile is achieved by the combination and placement of spacers  72 ,  74 ,  76  and  78  in combination with the placement, length and stiffness of stiffening sleeves  82 . The overall target weight of shaft  12  can be tuned by the choice of weights  80 . The moment-of-inertia can be tuned by the location of the weights  80 . 
         [0066]    In practice, the golfer would choose the spacers  72 ,  74 ,  76  and  78  and location to affect the position of the kick-point of the overall shaft  12 . For instance, to achieve a mid kick-point spacers  72 ,  74   76  and  78  would be placed at the proximal end of support member  84 . To further affect the bending profile a golfer would choose the number, length, stiffness and placement of any number of stiffening sleeves  82  on support member  84 . After placement of both the spacers  72 ,  74 ,  76  and  78  as well as stiffening sleeve  82  a final target weight would be achieved by virtue of weights  80 . A final moment-of-inertia would be achieved by placing the weights  80  along support member  84  to affect the choice of moment-of-inertia required. Support spacers  72 ,  74 ,  76  and  78  are locked in place along support member  84  by virtue of a set screw arrangement. 
         [0067]      FIG. 11  reveals yet another embodiment of the current invention wherein the inner shaft  16  is in direct contact with the outer shaft  18  serving to eliminate the need for spacers  15 ,  17  and  19 . The combination of the inner shaft  16  structure with the outer shaft structure  18  forms in effect a complete golf shaft  12  whose combined bending profile, wall thickness, weight and torque are identical to a typical golf shaft  12 . In this manner the bending profile of the outer shaft  18  directly influences the inner shaft structure  16  since the outer surface of the inner shaft structure  16  is in direct contact with the inner surface of the outer shaft structure  18 . 
         [0068]      FIG. 12  reveals yet another embodiment of the current invention where in lieu of spacers  15 ,  17  and  19  a thin layer of fluid  32  is provided between outer shaft structure  18  and inner shaft structure  16  in order to mechanically convey the loading of the outer shaft structure  18  to inner shaft structure  16 . Those skilled in the art will recognize that virtually any fluid or material can be used in lieu of fluid  32  and that in doing so does not deviate from the spirit or intent of the current invention.