Patent Document

BACKGROUND OF THE INVENTION 
     This invention relates in general to golf clubs and, more particularly, to golf clubs having weight inserts. 
     The swing weight of a golf club can be thought of as the ratio of the head weight to the grip weight measured at a consistent point of reference, typically 14 inches from the butt end of the club. Swing weights were, at one time, measured in ounces up to as much as 28 ounces, or more. Today, swing weight is most commonly measured on an arbitrary alphabetical scale from “A” to “G”, with “A” swing weighted clubs having relatively lower head weight to grip weight ratio and “G” swing weighted clubs having the highest ratio of head weight to grip weight. For a matched set of clubs, the swing weight should be consistent throughout the set for optimum performance (e.g., “D 3 ” for a set of medium swing weighted men&#39;s clubs). 
     Because the swing weight of any particular club is a function of the shaft weight, club head weight, and grip weight, as well as manufacturing tolerances in the weight of all of these, clubs are advantageously swing weighted to the customer&#39;s specifications after final assembly. Ordinarily, this is accomplished by attaching a small balance weight to the exterior of the club, usually in a pocket formed in the outside wall of the club for this purpose. 
     Golf clubs come in many different styles and model designations all of which must be swing weighted at some point during their manufacture. In many cases, the club&#39;s model designation is imprinted on the balance weight so that it is visible once the balance weight is installed. Using an imprinted balance weight allows for ready identification of the model designation of the particular golf club. As can be readily determined from the foregoing, in order for a manufacturer to be able to swing weight each of its models across the full range of swing weights, it must maintain a separate inventory of swing weights imprinted for each model of club. Some economy of scale can be achieved by manufacturing the balance weights for each model of club so that they are all the same size and shape. The mass is then varied by varying the density (e.g., by using a tungsten-loaded thermoplastic in which the tungsten density is varied). This way a single mold can be used for all of the balance weights for a single club model. This does not, however, solve the inventory problem engendered by the necessity of having available a complete array of balance weights imprinted with markings for each club model. 
     One model of prior art iron-type club head  100 , as shown in  FIGS. 10 and 11 , incorporated a two-piece weight  102  disposed in the back face  104  of the club head  100 . The club head  100  included a hosel  106  for receiving a golf shaft (not shown) and a cavity  108  for receiving the weight  102 . It will be understood that the weight  102  consists of a weight member  110  and a weight cover  112  that is locked in place over the weight member  110  by utilizing clips  114  on the weight cover  112  that snap into grooves  116  in the weight member  110 . 
     SUMMARY OF THE INVENTION 
     The present invention satisfies the foregoing need by providing a golf club head having a balance weight, selected from a plurality of balance weights, mounted in a weight cavity formed in the golf club head. A cover, which according to an illustrative embodiment is imprinted with information such as the club model designation, is mounted to the club head body so that it substantially covers the balance weight. By providing a single cover for each model of club, in combination with a plurality of weights that are interchangeable between models, the total number of balance weights that must be maintained in inventory is significantly reduced. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The present invention will be better understood from a reading of the following detailed description, taken in conjunction with the accompanying drawing figures in which like references designate like elements, and in which: 
         FIG. 1  is a front perspective view of a golf club head incorporating features of the present invention; 
         FIG. 2  is a rear exploded perspective view of a golf club head incorporating features of the present invention; 
         FIG. 3  is a rear perspective view of the club head shown in  FIG. 2  as assembled; 
         FIG. 4  is a partial cross-section of the club head shown in  FIG. 3  taken along line  4 - 4 ; 
         FIG. 5  is an enlarged view of a portion of  FIG. 4 ; 
         FIG. 6  is an alternative embodiment of a balance weight and cover incorporating features of the present invention; 
         FIG. 7  is another alternative embodiment of a balance weight and cover incorporating features of the present invention; 
         FIG. 8  is an additional alternative embodiment of a balance weight and cover incorporating features of the present invention; 
         FIG. 9  is yet another alternative embodiment of a balance weight and cover incorporating features of the present invention; 
         FIG. 10  is a rear perspective view of a prior art iron-type club head; and 
         FIG. 11  is a cross sectional view of the club head of  FIG. 10 . taken along line  11 - 11 . 
     
    
    
     DETAILED DESCRIPTION 
     The drawing figures are intended to illustrate the general manner of construction and are not necessarily to scale. In the detailed description and in the drawing figures, specific illustrative examples are shown and herein described in detail. It should be understood, however, that the drawing figures and the detailed description are not intended to limit the invention to the particular form disclosed, but are merely illustrative and intended to teach one of ordinary skill how to make, and/or use the invention claimed herein and for setting forth the best mode for carrying out the invention. 
     With reference to  FIGS. 1 and 2 , a golf club head  10  comprises a body  12  and a hosel  14 , which is counterbored for receiving one end of a shaft  16 . The body  12  has a front face  18  adapted for impacting a golf ball and body surface or skirt  20  disposed between the crown  22  and sole  24  of body  12 . Body surface  20  includes a weight cavity  26  defined by a bottom wall  28  and a side wall  30 . In the illustrative embodiment, golf club head  10  is a hollow metal wood driver having a weight of approximately 200 grams. The weight cavity  26  is elliptical in shape and measures approximately 35 millimeters along the major axis, 15 millimeters along the minor axis and is approximately 5-10 millimeters in depth. 
     Because the golf club head  10  is of a fixed weight, in order to provide the various swing weights necessary to accommodate different shafts and golfer&#39;s preferences, a balance weight  32 , is selected from a plurality of balance weights and attached to body  12  within cavity  26 . In the illustrative embodiment, the plurality of balance weights are identical in size and shape, but range in mass from 2.5 to 21.5 grams in one-gram increments. Once the appropriate balance weight  32  has been attached to body  12 , a cover  34  is also attached to the club head body so that it covers substantially all of the balance weight  32 . In the embodiment of  FIG. 2 , cover  34  is attached to balance weight  32  by means of tabs  35  that engage corresponding slots  37  formed in lateral side  52  of balance weight  32 . (Alternatively, the tabs  35  could be formed on the balance weight  32  and the slots  37  could be formed in the cover  34 .) Cover  34  is selected from a plurality of covers each of which carries information appropriate to the particular golf club, for example the club model designation and any other information of use to the golfer or golf club fitter (e.g., information representative of loft, lie, swing weight, etc.). As shown in  FIG. 3 , once assembled, the information cover provides a ready means of identifying the club model. 
     With reference to  FIGS. 4 and 5 , balance weight  32  is attached to body  12  within weight cavity  26  by means of a pair of threaded fasteners  36  and  38  which are threaded into bottom wall  28  of cavity  26 . Preferably an anaerobic adhesive such as LOCTITE is applied to the threads of threaded fasteners  36  and  38  prior to assembly. Once balance weight  32  is installed, cover  34  is attached to balance weight  32 . As seen in  FIGS. 4 and 5 , cover  34  follows substantially the contour of body surface  20  but does not cover the heads of threaded fasteners  36  and  38 . This allows threaded fasteners  36  and  38  to be accessible in the event balance weight  32  should need to be changed, for example if a new shaft is installed or the golfer&#39;s preferences change. 
     With reference to  FIG. 6 , according to an alternative embodiment, balance weight  32   a  is attached to body  12  within weight cavity  26   a  by means of a pair of threaded fasteners  36  and  38  which are threaded into bottom wall  28  of cavity  26   a . Once balance weight  32   a  is installed, cover  34   a  is attached to balance weight  32   a  within cover cavity  54  by means of a layer of adhesive  40  applied between inner surface  42  of cover  34   a  and floor  56  of cover cavity  54 . Outer surface  46   a  of cover  34   a  is formed to follow the general contour of body surface  20  and extends over threaded fasteners  36  and  38  to provide a continuous, smooth surface. Alternatively, as with the embodiment of  FIG. 5 , outer surface  46  may stop short of threaded fasteners  36  and  38  so that they are easily accessible in the event balance weight  32   a  should need to be changed. 
     In another alternative embodiment as shown in  FIG. 7 , balance weight  32   b  is attached to body  12  within weight cavity  26   b  by applying a layer of adhesive  48  between bottom wall  28   b  of cavity  26   b  and lower surface  50  of balance weight  32   b  as well as between side wall  30   b  of cavity  26   b  and lateral side  52  of balance weight  32   b . Cover cavity  54   b  is defined by a floor  56   b  and reveal  58   b  in which is formed a slot  60 . A corresponding tab  62  is formed in the perimeter surface  64  of cover  34   b . Once balance weight  32   b  has been attached to body  12  cover  34   b  is attached to balance weight  32   b  by snapping tab  62  into the corresponding slot  60 . 
     With reference  FIG. 8 , in an additional alternative embodiment, balance weight  32   c  is attached to body  12  inside weight cavity  26   c  by means of threaded fasteners  36  and  38  which are threaded into bottom wall  28   c  of cavity  26   c . A slot  66  is formed in side wall  30   c  of cavity  26   c . A corresponding tab  68  is formed in the perimeter surface  70  of cover  34   c . Once balance weight  32   c  is installed, cover  34   c  is installed by snapping tab  68  into corresponding slot  66  formed in side wall  30   c  of weight cavity  26 . 
     With reference  FIG. 9 , in yet another alternative embodiment, balance weight  32   d  is attached to body  12  inside weight cavity  26   d  by means of threaded fasteners  36  and  38  which are threaded into bottom wall  28   d  of cavity  26   d . Cover  34   d  is then installed by pressing a plurality of pins  72 ,  74  into the corresponding recesses  76 ,  78  formed in the heads of threaded fasteners  36  and  38 . Optionally, an adhesive, such as a cyanoacrylate adhesive may be used to permanently secure cover  34   d  to balance weight  32   d    
     Although certain illustrative embodiments and methods have been disclosed herein, it will be apparent from the foregoing disclosure to those skilled in the art that variations and modifications of such embodiments and methods may be made without departing from the spirit and scope of the invention. For example, an adhesively bonded balance weight in cooperation with a cover that snaps into a slot formed into the side wall of the cavity, threaded weight in cooperation with a cover that is adhesively bonded to the weight cavity or any combination of threaded, bonded, or snap-in attachments are all considered within the scope of the present invention. Accordingly, it is intended that the invention should be limited only to extent required by the appended claims and the rules and principals of applicable law.

Technology Category: 1