Abstract:
A golf club includes a clubhead having a striking face, a threaded cylindrical chamber behind and generally parallel to the face, and a threaded cylindrical weight member in the chamber. A hosel is attached to the cylindrical weight member and has a shaft receiving socket with a non-circular portion and a threaded portion, the shaft having a hosel engaging end with a mating non-circular cross section and a ferrule having threads engagable with the threaded portion of the socket. A second embodiment includes a clubhead which is symmetrical so that the hosel may be attached at either end to make the club ambidextrous. Some different structures for attaching the hosel to the cylindrical weight member provide for variations in the loft of the club. Another embodiment includes an asymmetric movable weight member which engages the head within a cavity therein and is adjustable both longitudinally and by changing the location of its center of gravity. A special tool mates with each of the adjustments to provide complete and accurate club assembly and adjustment. Additional embodiments include a hollow clubhead with a removable sole plate providing access for adjusting the position of various weights within the clubhead.

Description:
This continuation-in-part application claims benefit of U.S. Non-Provisional Application Serial No. 08/926,557 filed Sep. 10, 1997, now U.S. Pat. No. 6,149,533, issued Sep. 10, 1997, which is based on U.S. Provisional Application No. 60/025,236 filed Sep. 13, 1996. 
    
    
     BRIEF SUMMARY OF THE INVENTION 
     In recent years, there has been a tremendous resurgence of interest in the game of golf. This has been accompanied by a number of new designs of golf clubs all promising to lengthen drive, increase accuracy and turn duffers into professional quality players. Many of these promises have gone unfulfilled so the search continues for improved concepts which really perform. 
     I have been involved in the design of mechanical systems in which I have looked to basic fundamentals that often result in simplification, yet improved, performance. I can see that many of the attempts to design improved golf clubs may have merit, but it is my belief that some simple fundamental changes can produce a significantly better performing golf club. 
     There have been many attempts to enlarge the sweet spot of a clubhead. This has been done by enlarging the head in its entirety, and in certain cases, by distributing the volume of material to the edges of the clubhead. These attempts are designed to enlarge the sweet spot or, more precisely, to allow a slightly miss hit ball to have less effect upon the transfer of energy from the clubhead to the ball and to prevent twisting of the club in the hands of the golfer upon impact resulting in a hook or slice. 
     There is also an interest in avoiding twisting of the club in the hands of the golfer from too light a hold on the grip of the golf club. Yet, an excessively tight hold will result in tensing of arm muscles resulting in loss of control of the golf swing. 
     With the foregoing state of the art, I have recognized that different approaches can fill the need for enlarged sweet spot or improved performance in general. 
     Specifically, in one embodiment of my invention, I employ a hollow clubhead which has a plurality of individual chambers extending from the club face rearward through its body. Contained within each chamber are movable mass members which move subject to the force of the swing and the force upon impact with the ball. The force acting on the mass members during swing is principally centrifugal force and the force upon impact tends to drive the mass members into contact with the inside of the club face to transfer their kinetic energy to the club face at and shortly after the impact with the golf ball providing additional energy as well as absorbing undesirable vibrations. I have determined that it is desirable that the internal walls defining each one of the chambers be curved to conform with the arc of the swing. 
     I have also discovered that in connection with the movable weight within the clubhead that it is possible using an eccentric weight member of uniform, preferably threaded, exterior that the center of gravity of the weight and of the entire clubhead may be shifted to higher or lower positions in the head and actually farther forward or toward the rear of the clubhead. 
     In another embodiment of my invention, the clubhead is separable from the hosel and is adjustable in the angle of the head face. It also allows for the adjustment of a movable mass member located behind the face of the club, which concentrates the force of the club and also enlarges the sweet spot for greater accuracy. The mass member is preferably an aluminum cylindrical weight threaded into the body of the club and movable longitudinally parallel to the face of the club. With the readily separable hosel and clubhead, it is easy to attach a different shaft and hosel to the clubhead. 
     Once the mass member is adjusted to the desired position, it is not normally readjusted as the club is in use. 
     A modification of the above embodiment incorporates an internally adjustable weight member which can be readily adjusted by a golfer to fine tune the weight distribution of his club serving as an anti hook or slice device. 
     In my analysis of this invention, I have also discovered that even in apparently identical shafts made by the same manufacturer, the wall thickness of hollow shafts vary from as little as 0.004 in. to 0.014 in. at various positions around the shaft tube. This has a great effect on the stiffness and flexibility of the shaft. In other words, the shaft may respond quite differently depending on its orientation with respect to the face of the club. Therefore, I have provided a shaft attachment feature which allows a selection of angular orientation of the shaft head positions. 
     In order for the shaft to be properly attached to the head and for the weight positioning, as is described herein, within the head, I have produced a novel adjusting and locking tool which is also disclosed and claimed. 
     As a result of the development of the foregoing embodiments, the system of this invention provides: 
     a. interchangeable/quick detachable shafts; 
     b. totally adjustable center of gravity; 
     c. full range of adjustable loft; 
     d. adjustable lie; and 
     e. open or closed face adjustment options. 
     Additionally, for the manufacturer, it provides: 
     a. cost effective manufacturing; 
     b. major reduction in inventory including the same head for right or left handed players; 
     c. additional multiple shaft sales; 
     d. additional retrofitting after initial sale; 
     e. a precise custom fitting tool; and 
     f. most technologically advanced golf club offered. 
     For the user, it also provides: 
     a. custom fitting to give greater distance, accuracy, control and consistency; 
     b. a secure investment as the system can be reprogrammed as a golfer&#39;s level of skill changes; 
     c. positive alternatives for the physically challenged; and 
     d. allows simple change of shaft by the user himself. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING(S) 
     This invention may be more clearly understood with the following detailed description and by reference to the drawings in which: 
     FIG. 1 is a perspective view of a golf club incorporating one or more embodiments of my invention; 
     FIG. 2 is a sectional view through the handle of the golf club of FIG. 1; 
     FIG. 3 is a front elevational view, partly in section showing internal structure of FIG. 2 on an enlarged scale; 
     FIG. 3A is a block diagram of the device of FIGS. 1-3; 
     FIG. 4 is a sectional drawing of a golf clubhead and hosel incorporating another embodiment of my invention; 
     FIG. 5 is a view taken along line  5 — 5  of FIG. 4; 
     FIG. 6 is an exploded view of a portion of the structure of FIGS. 4 and 5; 
     FIG. 7 is a top view of the golf clubhead and hosel of FIGS. 4-6 with internal parts shown in dashed lines; 
     FIG. 8 is a sectional view of a golf clubhead constituting a modification of the golf clubhead of FIG. 4; 
     FIG. 8A is a fragmentary view of a portion of a clubhead and hosel similar to FIG. 8 showing a modification thereof; 
     FIG. 8B is an end view of the hosel of FIG. 8A; 
     FIG. 8C is an end view of the clubhead of FIG. 8A showing how the angle of the clubhead may be varied; 
     FIG. 9 is a top view, partly broken away, of a golf clubhead incorporating a third embodiment of my invention having internal movable mass members; 
     FIG. 9A is a view similar to FIG. 9 but in which the mass members are moved toward the face of the club; 
     FIG. 9B is an enlarged plan view of a typical rubber O-ring which may be used as a mass member in the embodiment of FIGS. 9 and 9A; 
     FIG. 10 is a fragmentary view of a portion of the golf clubhead of FIGS. 9 and 9A; 
     FIG. 11 is a sectional view taken along line  11 — 11  of FIG. 10; 
     FIG. 12 is a perspective view showing the packaging of a golf club as shown in FIGS. 4-8C; 
     FIG. 13 is an exploded view of another embodiment of my invention; 
     FIG. 14 is a view of the assembled clubhead and hosel of FIG. 13; 
     FIG. 15 is a perspective view from the opposite side of the cylindrical member mating with the hosel of FIG. 13; 
     FIG. 16 is a sectional view taken through the clubhead and hosel of FIG. 14; 
     FIG. 17 is a fragmentary elevational view of the face of the hosel of FIG. 13; 
     FIG. 18 is a diagrammatic view of the end of the clubhead showing the variation in loft or club face angle made possible with the hosel/clubhead design of FIGS. 13,  14  and  15 ; 
     FIG. 19 is a diagrammatic view showing how the internal weight member of FIG. 13 is movable parallel to the face of the club to adjust the weight balance of the club; 
     FIG. 20 is an exploded view of an alternate hosel and removable shaft usable with the golf club of FIGS. 13-19; 
     FIG. 21 is a fragmentary cross sectional view of the shaft and hosel of FIG. 20; 
     FIG. 22 is a cross sectional view taken along line  22 — 22  of FIG. 21; 
     FIG. 23 is a cross sectional view taken along line  23 — 23  of FIG. 21; 
     FIG. 24 is a perspective view of an adjusting and locking tool for the golf club of this invention; 
     FIG. 25 is a plan view thereof; 
     FIG. 26 is a front end elevational view thereof; 
     FIG. 27 is a rear end elevational view thereof; 
     FIG. 28 is a bottom perspective view of another clubhead incorporating my invention; 
     FIG. 29 is a bottom view of the clubhead of FIG. 28 with a portion of the bottom plate removed to show another embodiment of movable mass member; 
     FIG. 30 is a sectional view taken along line  30 — 30  of FIG. 29; 
     FIG. 31 is a bottom view of the clubhead of FIG. 28 with a portion of the bottom plate removed to show another embodiment of movable mass member; and 
     FIG. 32 is a sectional view on a reduced scale of the clubhead of FIG. 28 showing another embodiment of movable mass member. 
    
    
     DETAILED DESCRIPTION 
     It is recognized that a consistent grip is a significant part of a good golf swing. If the grip is too loose, the club may twist in the golfer&#39;s hand upon impact with the ball resulting in badly hit drives. If the grip is too tight, there is an excessive tensing of many muscles of the upper body which frequently results in “topping” the ball or hitting it in a wrong direction. The device of FIGS. 1-3A will notify a player, either visibly or audibly, if he or she is applying the same amount of grip pressure each time he or she is swinging the golf club. 
     FIG. 1 shows a typical golf club  10  of the type referred to as a “wood” but which is often made of metal. FIG. 2 illustrates the grip  12  of the golf club of FIG.  1 . 
     Applicant has determined that a piezoelectric device  14  may be incorporated into the rubber grip  12  of the club  10 . The piezoelectric device  14  is a planar sheet attached to a cylindrical member located within the handle  12  such that when a player grips the rubber handle a squeezing force is applied to piezoelectric device  14  causing it to generate a small electrical voltage. The harder the piezoelectric device  14  is squeezed, the higher its voltage output. This voltage output is supplied to a small circuit board  16  which converts the voltage to a measured output which, at a particular voltage level, will illuminate a LED (light emitting diode)  18  or actuate a small sound transducer to make an audible sound when the grip is recognized as being at a desired level. Connected into the circuit board  16  is a small rheostat or rotary switch (not shown) to set the level of pressure sensitivity to suit the personal requirements of each individual. With this device, an individual can set the rheostat to a desired level and then can learn to be more consistent with his grip on the club handle  12 , by increasing their grip each time just until the LED is illuminated or the audible output occurs. If desired, a second LED  20  of a contrasting color may be wired into the circuit  16 , which is responsive to an excessive grip pressure. Commercially available piezoelectric devices and circuits are available as follows: AMP Inc., P.O. Box 799, Valley Forge, Pa. 19482. 
     FIG. 3A is a block diagram indicating the electrical connections and elements of the structure of FIGS. 2 and 3. The piezoelectric element  14  responds to a grip on the handle  12  by generating a voltage which is supplied to the circuit board  16 . Circuit board  16  includes a rheostat which sets a threshold and a comparison circuit which compares the generated voltage against the threshold value. If the threshold voltage is exceeded, the LED  20  will be illuminated, or an acoustic device will emit a sound. 
     FIG. 4 is a sectional view through a golf clubhead  24  incorporating another embodiment of my invention and FIG. 5 is a view taken along line  5 — 5  of FIG.  4 . In FIGS. 4 and 5, golf clubhead  24  is shown with a relatively large cylindrical chamber  26  located just inside the club face  28  (FIG.  5 ). To provide a means for effecting an optimum balance of the clubhead, chamber  26  includes fine inside threads engaged with threads on a cylindrical weight member  30  which preferably would weigh about 6½ to 7½ oz. Member  30  also includes a threaded bore  32  along its axis and a pair of radially displaced bores  34  and  36 . 
     A hosel  38  includes a bore  40  designed to receive a bolt  42  which engages the threads of bore  32  to secure the hosel  38  to weight  30 . Hosel  38  also includes a pair of pegs  44  and  46  which align with bores  34  and  36  to prevent radial displacement of the cylindrical weight member  30  relative to the hosel  38 . A counterbore  48  concentric with bore  40  permits the bolt  42  to be turned into threaded bore  32  until its head contacts a shoulder  50  of hosel  38 . 
     A golfer using this club may experimentally determine the axial position of weight member  30 , which appears to provide the best balance and least tendency for twisting and producing hooked or sliced drives. A tendency to hook the ball, for example, would indicate the weight member  30  is too far out on the toe of the clubhead  24  and, with bolt  42  disengaged from bore  32 , weight member  30  may be turned within chamber  26  to thereby move weight member  30  axially inwardly or away from the toe of clubhead  24 . Consistent slices would indicate weight member  30  is too far inward and should be moved outwardly toward the toe of clubhead  24 . The angle of the clubhead  24  can be varied by turning the head on the threads of weight member  30  with bolt  42  loose or disengaged from bore  32 . Once the position is established for weight member  30  and the clubhead angle established, members  30  and  24  are cemented or otherwise fastened together so that clubhead  24  will not rotate on impact with a ball. A single clubhead may in this manner be used to provide a driver or any of the other fairway woods. This flexibility can substantially reduce the inventory of clubs carried by a store, pro shop or manufacturer. 
     FIG. 6 is an exploded view of the structure of FIGS. 4 and 5. In this view weight member  30  is shown axially aligned with chamber  26  and bolt  42  aligned with bore  40  and counterbore  48  of hosel  38 . Also shown are bores  34  and  36  of weight member  30  and mating pegs  44  and  46 . 
     FIG. 7 is a top view of clubhead  24  showing face  28  and hosel  38 . Shown in dotted outline are internal parts including weight member  30  in chamber  26 , bolt  42  in bore  32  and peg  44 . 
     FIG. 8 is a view of a clubhead  24 A similar to FIG. 4 but modified to permit a golfer to fine tune the weight distribution of head  24 A. In this view, parts which are, or may be, the same as the parts of the embodiment of FIGS. 4-8 are given the same numerals. Thus hosel  38  includes a bore  40  and pegs  44  and  46  which align with bores  34 A and  36 A to prevent radial displacement of cylindrical weight member  30 A relative to the hosel  38 . Cylindrical weight member  30 A includes an axial bore  32 A which receives a bolt  42  to be turned into threaded bore  32 A until its head contacts shoulder  50 . The head  24 A is secured to weight member  30 A by means of fine threads as described above, which threads make it possible to adjust the weight distribution of the clubhead and to vary the loft of the face of the clubhead  24 A. Once the position of weight member  30 A is established, it is cemented or otherwise secured to clubhead  24 A as described above. 
     Also formed in clubhead  24 A is a bore  52  in the outboard end of clubhead  24 A which is aligned with bore  32 A. A separate counterweight member  53 , which may be of about 14 grams, is threadedly engaged with threads in bore  32 A and is accessible through bore  53  by means of an Allen wrench or other suitable means to turn counterweight  54  to move it axially in bore  32 A. In this manner a golfer can fine tune the weight distribution of his club. 
     Should it be desired to make the club adjustable for loft or club face angle on a continuing basis, the opposing faces of a hosel  38 A and clubhead  24 A may be formed with mating serrations  60  on hosel  38 A and  64  on clubhead  64 A as shown in FIG.  8 A. By loosening bolt  42 , the clubhead  24 A may be rotated a small amount relative to hosel  38 A after which the bolt  42  is tightened, pressing the serrated surfaces  60  and  64  together and preventing any rotation of the clubhead  24 A upon impact with a ball. The serrations may be formed integrally with hosel  38 A and clubhead  24 A or preferably, be formed on separate washer-like members  58  and  62  which are then cemented or otherwise secured to hosel  38 A and clubhead  24 A as shown on FIG.  8 A. Other equivalent fastening means could be employed. 
     It is useful to place index marks on the top surfaces of the hosel  38 A and the clubhead  24 A so that the golfer will have a clear idea of how much loft he is selecting. A given club may be set up with an initial loft of 14° and be adjustable in 1° or 2° increments over a range of, for example, 8° to 20°. 
     FIG. 8B is a fragmentary end view of hosel  38 A with serrated member  58  attached. The surface of member  62 , attached to clubhead  24 A, would appear essentially identical as shown in FIG.  8 C. With this described structure, the clubhead may be rotated relative to the hosel as shown in FIG.  8 C. 
     Shown in FIG. 9 is a third embodiment of my invention including a golf clubhead shown at numeral  54  including a face  56  and a plurality of internal chambers  57 ,  58 ,  60  and  62 . Separating chambers  56 - 62  are a plurality (in this case  3 ) of curved parallel walls  64 ,  66 , and  68 , which, at their point of connection, are perpendicular to face  56 . Positioned in chambers  56 - 62  are movable mass members  70 . Preferably, the end surfaces of chambers  57  and  62  are also parallel to the surfaces of walls  64 ,  66  and  68  and also are contoured with concave radii the same as walls  64 ,  66  and  68  as shown in FIG.  11 . The mass members  70  may be rubber O-rings as shown (greatly enlarged) in FIG. 9B, ceramics, or carbongraphics, to achieve a desired mass. A preferred overall head  54  weight is in the range of 7½ oz. to 10 oz. of which 14 to 50 grams are movable mass members  70 . 
     When the golfer swings the club toward the ball, the mass members  70  will tend to accumulate toward the rear of the clubhead and will be held there by centrifugal force. Upon impact with the ball, mass members  70  will almost instantly move against the inside of the club face  56  to transfer their kinetic energy to the ball as shown in FIG.  9 A. 
     FIG. 10 is a perspective view of a broken away portion of clubhead  54  showing a portion of the inside of face  56  and one of the parallel walls (in this case, wall  66 ) adjoining face  56 . FIG. 11 is a sectional drawing taken along line  11 — 11  of FIG.  10  and shows that the wall  66  is concave on both sides. Walls  64  and  68  have the same contour as wall  66  as do the parallel end walls of chambers  57  and  62 . The principles of this concept could as well be applied to other sporting goods such as softball or baseball bats. 
     FIG. 12 is a perspective drawing of a packaged set of golf clubs made according to the embodiments of FIGS. 4-8. Since the clubhead  24  may be adjusted to provide a range of angles of lift from that of a driver (10°) to at least that of a No. 4 wood, which would be about 17-20°, only one clubhead is required for an entire set of woods. This clubhead may be placed on shafts of different lengths as desired. The handle length of a No. 4 wood is, of course, significantly shorter than that of a driver. The kit  71  includes, therefore, handles and shafts  72 ,  74 ,  76 , and  78 , all of which attach to head  24 , since they all have hosels identical to hosel  38 . Also included is a tool  80  for removing and replacing bolt  42 . Bands  82  and  84  secure tool  80  as well as some tees  86 . Pouches  88  and  90  are included for storage of golf balls or other items. 
     FIG. 13 is an exploded view of an additional embodiment of my invention. A clubhead  100  includes a large diameter threaded passageway  102  extending through its entire length and parallel to the club face  104 . A weight member  106  is threadedly engaged with the threads  108  in passageway  102  and is movable along the passageway to adjust the weight balance of the club. A weight and attachment member  110  is also threadedly engaged with the threads  108  in passageway  102  and is turned into passageway  102  until it is approximately flush with the end  112  of clubhead  100 . 
     Member  110 , whose opposite end is shown in FIG. 15, includes a series of circumferential ports radially outwardly displaced from its axis. A pair of pins  114  and  116  are placed in two of the ports approximately 180 degrees apart. Member  110  also includes a collar portion  118  extending outwardly along its axis, which is internally threaded and which fits into an opening  120  in a hosel  122 . The face  124  of hosel  122  includes a series of circumferential ports spaced radially outwardly from an opening  120 , one of which  126  is slotted or elongated. 
     A bolt  128 , passing through hosel  122 , secures hosel  122  to member  110 . At the opposite end of clubhead  100  is a cylindrical plug  130 , which is threadedly engaged with threads  108  to close the end of the clubhead. Plug  130  includes an axial port  131 , which provides access for a tool to engage a projection  107  on weight member  106  to move it axially. Projection  107  has a rectangular cross section as shown in FIG.  13 . Plug  130  also includes a pair of spaced bores  133  which receive a tool for turning plug  130  in threads  108 . 
     FIG. 14 shows the golf club of FIG. 13 as assembled with the hosel  122  secured to one end of the clubhead (actually to member  110 , not shown) and with plug  130  closing the opposite end. A golf ball  132  is shown in phantom adjacent face  104 . 
     FIG. 16 is a sectional view through the clubhead  100  and hosel  122  as assembled. As indicated in phantom, weight  106  is movable along passageway  102  as desired to achieve the desired weight balance of clubhead  100 . Pins  114  and  116  are positioned in corresponding ports in hosel  122 , one of which is slotted port  126 . Also shown in phantom at the left end of clubhead  100  is an alternate position for hosel  122 , since clubhead  100  is symmetrical and may be assembled either right or left handed. 
     FIG. 17 is a fragmentary elevational view showing the face of hosel  122  with opening  120  and bolt  128  shown in section. The series of ten circumferential ports are shown including the slotted port  126  which is shown containing pin  114  and another port containing pin  116 . By judicious placement of pins  114  and  116 , any degree of loft of clubhead  100  may be provided within the normal range of loft from a driver to a number  4  wood. This is indicated in FIG. 18 wherein the diagram indicates that the clubhead  100  may be rotated to vary the angle of its face  104  by an angle alpha. In my preferred embodiment, pin  114  is fixed to member  110  and of larger diameter, and pin  116  is removable and may be located in any of the available openings in the fact of the hosel  122 . In any case, the bolt  128  secures the head at the desired loft. This change of loft can be made by a player during play if desired, but the preferred arrangement is that the weighted loft and shaft orientation can be adjusted by a professional golfer to meet the best arrangement for the player and all cemented in place. 
     FIG. 19 is a diagram showing the manner in which the weight  106  may be moved along the axis of clubhead  100  to shift the weight balance as desired. 
     FIG. 20 is an exploded view of a modified hosel  138  which receives a removable shaft  140 . Hosel  138  includes external threads  142  which engage threads  108  of clubhead  100  and also internal threads  144  which receive a weight member  146 . Weight member  146  includes a “C”-shaped cut out  148 , which mates with a special tool, described below, to turn member  146  within the threads  144 . Since cut-out  148  is concentrated on one side of member  146 , turning of member  146  effects a significant modification in the weight balance near the heel of the face of the club. The weight member has its center of gravity displaced from the axis of rotation. 
     Shaft  140  is received in a hollow generally cylindrical fitting  150  which has a hexagonal surface  152  over part of its length and a tapered lower end  154  which fits into a socket  157  in hosel  138 . Axially movable on shaft  140  is a threaded cylindrical ferrule  156 , which has threads  158  engaged with threads on the upper part of hosel  138 . This structure is shown on FIG. 21 wherein fitting  156  is shown seated in socket  157  in hosel  138 . The internal bore in hosel  138  also has a hexagonal cross-section to receive fitting  150 . In this view, ferrule  156  has been moved down the shaft  140  and threads  158  are engaged with internal threads in the top of hosel  138 . With the arrangement shown, it is apparent that shaft  140  is readily removed and replaced with a longer or shorter shaft as desired, or simply rotated to change the stiffness or flexibility of the shaft. 
     FIG. 22 is a cross-sectional view taken along line  22 — 22  of FIG.  21 . On this view, it is seen that the threads  158  of ferrule  156  are engaged with those on hosel  138  with shaft  140  passing through the center. 
     FIG. 23 is a cross sectional view taken along line  23 — 23  of FIG.  21 . This view shows the fitting  150  with its hexagonal sides, which mate with the hexagonal bore in hosel  138 . 
     In order to achieve the maximum value of my invention, I have discovered a real need for an adjusting and locking tool which is designed to make precise adjustments in the location of the weight within the clubhead and to attach, adjust and remove the shaft from the clubhead and to open and close the clubhead to allow the adjustments in longitudinal weight balance. 
     Referring now to FIG. 24, in combination with FIGS. 25 and 27, an adjusting and locking tool  160  may be seen. The tool  160  includes a handle portion  161 , and at its front end, a threaded section  162  which terminates in an arcuate working tool end  163  shaped to match with the arcuate opening  148  in the weight  146  of FIG.  20 . 
     An internally threaded locking ring  164  includes a locking screw  165  to hold the locking ring  164  at any longitudinal position along the length of the threaded portion  162 . 
     At the opposite end of the tool  160  from its operating heads  163  is a slotted wrench portion  166 . Barely showing in FIG. 24 are a pair of spanner wrench pins  170  and  171  which are used to remove the plug  130  of FIG.  17 . 
     The slot  166  is dimensioned to engage the threaded ferrule  156  of FIG. 20 for loosening and tightening ferrule  156  when attaching or adjusting the club shaft  140 . 
     FIG. 28 shows another clubhead  180 , which incorporates a removable bottom or sole plate  182 . FIG. 29 is a bottom view of clubhead  180  with plate  182  removed; and FIG. 30 is a sectional view taken along line  30 — 30  of FIG.  29 . Secured to the inner side of the club face  184  is a member  186  having smooth face with a raised center section  188  comprising a track defined by pair of ridges  192 ,  194 , which provide purchase for an adjustable clamp  196  having jaws  198  which are moved toward each other or separated by means of a screw  199 . By loosening jaws  198 , clamp  196  may be moved along the track and then tightened in a desired position along the track. Secured to clamp  190  is a weight member  200 . By moving adjustable clamp  196 , weight member  200  may be repositioned along member  186  to thereby modify the weight balance of clubhead  180 . 
     FIG. 31 is a bottom view of clubhead  180  with the bottom plate  182  removed to show a still different arrangement of movable mass member. In this description, identical parts are given the same numerals as above. Adjustable clamp  196  is removably clamped to center section  188  as described above. 
     Attached to clamp  196  is a shaft, preferably a bolt  202  extending perpendicularly to center section  188  and carrying a weight member  204 , which is pivotable on shaft  202  to vary the position of its mass relative to clubhead  180 . Loosening the bolt  202  permits the weight member  204  to be moved to an alternate position as shown in dashed outline. By tightening the bolt  202 , the weight member  204  is secured in the desired position relative to clubhead  180 . 
     FIG. 32 is a sectional view similar to FIG. 30 showing a further embodiment of movable mass member as installed in the clubhead  180 . In this embodiment, the weight member  204 ′, which may be very similar to pivotable weight  204 , is shown supported on a bolt  202 ′, which is secured to the bottom plate  180 ′ by welding or epoxy cement. By loosening the nuts secured to bolt  202 ′, weight  204 ′ may be pivoted around bolt  202 ′ to achieve the desired weight balance of club  180  after which the nuts are tightened to secure weight  204 ′ in the desired position. As in the embodiments of FIGS. 30 and 31, some experimenting will, in most cases, be required to determine the best position of the weight. When the desired weight balance has been determined, the weight assemblies are secured in position by epoxy cement and the bottom plate secured to the clubhead. 
     From the foregoing, it will be appreciated that the golf club according to the present invention is extremely flexible and can be made to suit a large number of players, both right or left handed. This can significantly reduce the inventory of a professional golfer&#39;s shop. 
     The above-described embodiments of the present invention are merely descriptive of its principles and are not to be considered limiting. The scope of the present invention instead shall be determined from the scope of the following claims including their equivalents.