Abstract:
A variable length shaft assembly comprising at least one spacer, a shaft portion, and a threaded fastener, wherein the threaded fastener removably connects the spacer to the lower shaft, is disclosed herein. The variable length shaft assembly may further comprise at least two spacers that are stackable on a butt end of the shaft portion so a golfer can adjust the total length of the shaft. Methods of adjusting the length of a golf club shaft without damaging any portion of the shaft and variable length shaft kits are also disclosed herein.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
       [0001]    The present application is a division of U.S. patent application Ser. No. 13/544,536, filed on Jul. 9, 2012, which claims priority to U.S. Provisional Patent Application No. 61/577,366, filed on Dec. 19, 2011, the disclosure of which is hereby incorporated in its entirety herein. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not Applicable 
       BACKGROUND OF THE INVENTION 
       [0003]    1. Field of the Invention 
         [0004]    The present invention relates to a variable length shaft assembly that allows for quick, semi-permanent length adjustments. More specifically, the present invention relates to a variable length shaft whose length can be adjusted in a short period of time with the use of shaft spacers that are stackable on a butt end of the shaft. 
         [0005]    2. Description of the Related Art 
         [0006]    Customization of golf clubs to help golfers attain better shots and putts has become a popular and more prevalent practice in recent years. Golf club manufacturers and designers have devised various features to allow club fitters and golf club players to adjust certain characteristics of their clubs. Such characteristics include loft, lie, face angle, center of gravity (CG) location, and club length. 
         [0007]    Current technology provides two methods to adjust overall club length. One such method involves the destruction and removal of the grip on a shaft. Upon removal of the grip by peeling or tearing, the end portion of the shaft is trimmed to decrease the club length or an extension piece is affixed to the end of the shaft to increase its length. Aftermarket extensions are available specifically for this purpose; alternatively, extensions can be made from portions of other golf club shafts that are cut to the desired length and then inserted into the end of the first club&#39;s shaft. The extension piece must match the diameter of the existing shaft, so it is necessary at times to build up the diameter of the extension or existing shaft by adding layers of tape. This method requires that the user making the adjustments have access to potentially expensive new components and tools as well as having a high level of skill. It also causes damage to the original shaft and grip. 
         [0008]    The second method of adjusting club length involves replacing the entire shaft and grip using a semi-permanent head-shaft connection device that some manufacturers offer with their clubs, particularly with drivers. The existing shaft may be removed from the driver head and replaced with a different shaft that has either a shorter or longer length. This method is not possible on all clubs, however, as the head must have hardware that allows for removal of the shaft and replacement with a new shaft without damaging the head. 
         [0009]    A golfer who does not possess club altering skills or the necessary disposable income to purchase new components likely will be daunted by these two methods of adjusting club length. The first method requires the golfer to make use of several tools to remove the grip and cut the shaft if he or she desires a shorter length, and also to have materials such as tape and a replacement grip on hand to replace the grip and mend any damage caused to the shaft and grip. The skill set required to change the shaft length using this method is usually beyond the abilities of the average golfer, so the golfer would need to seek the services of a golf club fitter or technician to have their club length changed. The second method requires the golfer to buy an entirely new shaft at a different length, which can be very expensive, and also may require the golfer to retain a golf club fitter or technician to replace the shaft. 
         [0010]    Ultimately, the two methods described above require an inventory of spare components and above average technical skill, particularly with regard to the first method. It is therefore desirable to facilitate the change of a club&#39;s length using a faster, easier, and less expensive system and method than is currently available. 
       BRIEF SUMMARY OF THE INVENTION 
       [0011]    One aspect of the present invention is a variable length golf club shaft comprising a variable length golf club shaft comprising a shaft comprising a grip, a butt end, and a tip end, a shaft adapter, a spacer having an upper end and a lower end, a cap, and a fastener, which may be a bolt, wherein the shaft adapter is affixed to the butt end of the shaft, wherein the lower end of the spacer engages the shaft adapter, wherein the cap engages the upper end of the spacer, and wherein the fastener fixes the cap and the spacer to the shaft. The lower end of the spacer may comprise a keyed projection and the upper end of the spacer may comprise a keyed socket, and the spacer may have a molded urethane cover is disposed on an exterior surface. The molded urethane cover may be textured to help a golfer more securely grip the shaft. Each of the spacer, shaft, and the shaft adapter may further comprise at least one flat side and at least one curved side. In one embodiment, the shaft adapter may be removably affixed to the shaft. In other embodiments, the spacer may be composed of a plastic material, and the cap may comprise a bore and be composed of a lightweight metal material. 
         [0012]    Another aspect of the present invention is a golf club comprising a putter-type head comprising a face and a hosel, a shaft comprising a lower end sized to fit within the hosel, an upper end, and a grip, wherein the grip is disposed proximate the upper end of the shaft, wherein the upper end of the shaft comprises a bore, wherein the shaft is composed of a graphite material, and wherein the grip is composed of an elastomeric material, a shaft adapter comprising a bore, a threaded internal surface, and a keyed socket, the shaft adapter composed of a metal material, a plurality of spacers, each spacer comprising a lower end comprising a keyed projection, an upper end comprising a keyed socket, at least one curved side, at least one flat side, a through-bore, and a molded elastomeric cover disposed on the at least one curved side and the at least one flat side, wherein each of the spacers has a length of no more than 1.25 inches, a cap comprising a keyed projection, a socket, and a through-bore, the cap composed of an aluminum material, and an elongate bolt comprising a head and a threaded body, the elongate bolt composed of a metal material, wherein at least a part of the shaft adapter is bonded within the bore in the upper end of the shaft, wherein the keyed projection of each of the plurality of spacers fits within the keyed socket of the shaft adapter and within the keyed socket of each of the other spacers, wherein the keyed projection of the cap fits within the keyed socket of each of the plurality of spacers, and wherein the threaded body of the bolt extends through the through-bore of the cap and the through bore of each of the plurality of spacers and engages the threaded internal surface of the shaft adapter to secure the cap and the plurality of spacers to the shaft. 
         [0013]    In a further embodiment, the upper end of each of the spacers may comprise at least one shallow depression and wherein the lower end of each of the spacers may comprise at least one nub sized to fit within the shallow depression. In another embodiment, each of the plurality of spacers is not rotatable with respect to each other when assembled. 
         [0014]    Yet another aspect of the present invention is a kit comprising a golf club comprising a putter-type head affixed to a shaft, the shaft comprising a lower end sized to fit within the hosel, an upper end, a grip, and shaft adapter, a plurality of spacers, each spacer comprising a lower end comprising a keyed projection, an upper end comprising a keyed socket, at least one curved side, at least one flat side, and a through-bore, herein each of the spacers has a length of no more than 1 inch, a cap comprising a keyed projection, a socket, and a through-bore, and an elongate bolt comprising a head and a threaded body, wherein the keyed projection of each of the plurality of spacers fits within the keyed socket of the shaft adapter and within the keyed socket of each of the other spacers, wherein the keyed projection of the cap fits within the keyed socket of each of the plurality of spacers, and wherein the threaded body of the bolt extends through the through-bore of the cap and the through bore of each of the plurality of spacers and engages the threaded internal surface of the shaft adapter to secure the cap and the plurality of spacers to the shaft. 
         [0015]    In a further embodiment, the upper end of each of the spacers may comprise at least two shallow depressions, and the lower end of each of the spacers may comprise at least two nubs sized to fit within the shallow depressions. The shaft may be composed of a composite material, the cap may be composed of an aluminum alloy, and the spacers may be composed of a plastic material. In one embodiment, the putter-type head may be a blade putter head. In another embodiment, each of the plurality of spacers may comprise a molded elastomeric cover disposed on the at least one curved side and the at least one flat side. The elastomeric cover may be is textured, and the grip may have the same texture as the elastomeric cover. In a further embodiment, the elastomeric cover may be urethane. 
         [0016]    Having briefly described the present invention, the above and further objects, features and advantages thereof will be recognized by those skilled in the pertinent art from the following detailed description of the invention when taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0017]      FIG. 1  is a side, exploded view of a putter embodiment of the present invention. 
           [0018]      FIG. 2A  is a side, perspective view of the part of the putter circled in  FIG. 1 . 
           [0019]      FIG. 2B  is a cross-section view of the part shown in  FIG. 2A  along lines  2 B- 2 B. 
           [0020]      FIG. 3A  is a side, perspective view of an embodiment of a spacer of the present invention. 
           [0021]      FIG. 3B  is a bottom, perspective view of the spacer shown in  FIG. 3A . 
           [0022]      FIG. 3C  is a top, perspective view of the spacer shown in  FIG. 3A  associated with another spacer. 
           [0023]      FIG. 4  is a top, exploded view of the spacer shown in  FIG. 3C  and a cap. 
           [0024]      FIG. 5  is an exploded view of the cap, spacers, and bolt of the present invention. 
           [0025]      FIG. 6  is an assembled view of the embodiment shown in  FIG. 5 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    The present invention is directed to a variable length shaft that provides club length adjustability. In particular, the present invention is directed to adjustable shafts for belly putters, so that golfers can adjust the overall length of the club to better suit their putting skills. 
         [0027]    The present invention provides golfers with a system and method to easily, quickly and inexpensively modify the length of their putters, particularly belly putters, to have them perform in a desired manner. This invention will enable golfers to change their club length wherever they wish, including, but not limited to, at the practice range, the golf course, and their home. The present invention also is designed to avoid altering a club&#39;s swing weight or its “feel.” The components that are used to alter a club&#39;s length are small and can be carried in a pocket of the user&#39;s golf bag. Furthermore, the technical ability required to modify the golf club length according to this invention is minimal and its approach is intuitive and easy for a golfer to understand. 
         [0028]    A preferred embodiment of the present variable length shaft invention is shown in  FIGS. 1-6 . According to this embodiment of the invention, a golf club having a shaft  10  and a head  100 , preferably a putter head, is provided. An upper portion of the shaft  10  is encircled by a grip  15 , which preferably is textured to facilitate gripping by a golfer. The shaft  10  has an upper surface  12  at the top of the grip  15 , and has a length of 32 to 55 inches, more preferably 40 to 50 inches, and most preferably approximately 41 inches. The upper surface  12  of the shaft  10  includes a bore  13  sized to receive a shaft adapter  20 . The shaft  10  may be manufactured so that the bore  13  is integrally formed, or the bore  13  may be created later by a golfer or a specialist using appropriate machinery. 
         [0029]    The present invention also comprises a shaft adapter  20 , which preferably fits within the bore  13  so that an upper surface  22  of the adapter is flush with the upper surface  12  of the shaft  10 , as shown in  FIG. 5 . The shaft adapter  20  preferably includes a lower projection  24 , an upper barrel  26 , and a through-bore  28  sized to receive a fastener  50 . The part of the through bore  28  located within the lower projection  24  is threaded to receive mating threads  55  of the fastener  50 . The exterior surface of the projection  24  also provides an extended bonding surface when the shaft adapter  20  is assembled within the shaft  10  bore  13 . 
         [0030]    The upper barrel  26  of the shaft adapter  20  includes a keyed feature  25 , which may be an opening (not shown) or an interior structure having a stepped portion  23 , an example of which is shown in  FIGS. 2A and 2B . The keyed feature  25  is sized to receive a part of a spacer  30 , preferably the stepped portion  70  of a keyed projection  33  as described herein, and prevent it from rotating when engaged with the shaft adapter  20 . The shaft adapter  20  is preferably non-removably bonded within the shaft bore  13  with an adhesive, but in an alternative embodiment may comprise threads disposed at least on an external surface of the projection  24  that mate with internal threads disposed in the shaft bore  13  to permit the shaft adapter  20  to be removably secured within the shaft bore  13 . These external threads may also cover the external surface of the barrel  26  to further secure the shaft adapter  20  within the bore  13 . 
         [0031]    Once the shaft adapter  20  is assembled with the shaft  10 , one or more spacers  30  can be added to extend the overall length of the shaft  10 . Spacers  30 , shown in  FIGS. 3A ,  3 B,  3 C,  4 ,  5 , and  6 , each comprise a lower end  32  having a keyed projection  33 , which includes a stepped portion  70 , an upper end  34  having a keyed socket  35 , which comprises a protrusion  75 , a through-bore  31 , and an external surface  39 . The keyed projection  33  of each spacer  30  is sized to fit within the keyed socket  35  of each spacer  30 , so that the stepped portion  70  engages the protrusion  75  such that multiple spacers  30  can be non-rotatably stacked on top of each other as shown in  FIGS. 5 and 6 . In the preferred embodiment, the external surface  39  of the spacer  30  includes a curved portion  36  and a flat portion  37 , and further comprises a molded urethane cover  38  disposed on the external surface  39 , which preferably has the same texturing as the grip  15  to facilitate grasping by the golfer and make the assembly more aesthetically pleasing. 
         [0032]    The keyed projections  33  of each spacer  30  are shaped so that spacers  30  can be fitted to each other and to the shaft adapter  20  in only one configuration, preferably one in which the flat side  37  of each spacer  30  lines up. Each spacer  30  preferably has an overall length, from the top-most surface of the socket  35  to the end of the keyed projection  33 , of between 0.50 and 1.50 inches, more preferably a length between 0.75 and 1.25 inches, and most preferably a length of approximately 1 inch. In alternative embodiments, the external surface  39  may have any number of curved and/or flat portions  36 ,  37 , may have a cover formed of some other elastomeric or graspable material, and may have another overall length. In the preferred embodiment, the lower end  32  of the spacer  30  further comprises at least one nub  60 , as shown in  FIG. 3B , and the upper end  34  of the spacer  30  and the upper surface  12  of the shaft  10  each comprise at least one shallow depression  65 , as shown in  FIGS. 3A ,  3 C, and  4 . During assembly of each spacer  30  with other spacers  30  or the shaft  10 , the nubs  60  mate with the shallow depressions  65  to help line up the spacer  30  with whichever piece is disposed below. 
         [0033]    Once a golfer has increased the overall shaft length by assembling the desired number of spacers  30  with the shaft adapter  20 , the assembly is secured using a removable cap  40  and a fastener  50 . The fastener  50 , which is preferably an elongated bolt, has a head  52  and a threaded body  54 . The cap  40  has a keyed cap projection  42  comprising a stepped portion  78  that is sized to fit within the keyed socket  35  of each of the spacers  30  and engage the protrusion  75 , a cap socket  44  sized to receive the fastener head  52  and a through bore  46  to receive the threaded body  54 . As shown in  FIGS. 5 and 6 , to secure spacers  30   a,    30   b,    30   c,    30   d  to a shaft  10  comprising a shaft adapter  20 , the keyed cap projection  42  of the cap  40  is inserted into the top-most spacer  30   d  socket  35 , and the threaded body  54  of the fastener  50  is threaded through the through bores  31   a,    31   b,    31   c,    31   d,    46  of the spacers  30   a,    30   b,    30   c,    30   d  and the cap  40  and engaged with the internal threads of the shaft adapter  20  projection  24 . The fastener  50  can be tightened using a screwdriver or similar type of tool. Alternatively, if a golfer does not wish to extend the shaft  10 , the shaft adapter  20  can be covered with the cap  40  and secured by the fastener  50 . 
         [0034]    The present invention is useful because the shaft  10  itself never has to be changed in order to adjust the overall shaft length. This invention allows a golfer to increase or decrease the length of a golf club shaft without detaching the shaft  10  from the club head  100  or cutting or otherwise damaging any part of the shaft  10  or grip  15 . The parts of the invention may be sold with a golf club as a kit so that golfers can, immediately upon purchase, have all the parts necessary to adjust their new golf club&#39;s length. 
         [0035]    The parts of the present invention may be composed of any number of durable materials, including metals, plastics, rubbers, and composites. The shaft  10 , shaft adapter  20 , spacers  30 , cap  40  and fastener  50  may be composed of titanium, graphite or carbon composite, plastic, magnesium, aluminum, steel, or alloys of such materials, specifically stainless steel  17 - 7  or titanium  6 - 4 . The shaft  10  preferably is composed of graphite, the spacers  30  are preferably composed of plastic, the grip  15  preferably is composed of a rubber material, the cap  40  preferably is composed of an aluminum alloy, and the fastener and shaft adapter  20  preferably are composed of a metal material. The pieces of the embodiments disclosed herein may also be bonded together with an adhesive to prevent unwanted separation if the golfer decides he does not want to further adjust the overall club length. 
         [0036]    From the foregoing it is believed that those skilled in the pertinent art will recognize the meritorious advancement of this invention and will readily understand that while the present invention has been described in association with a preferred embodiment thereof, and other embodiments illustrated in the accompanying drawings, numerous changes, modifications and substitutions of equivalents may be made therein without departing from the spirit and scope of this invention which is intended to be unlimited by the foregoing except as may appear in the following appended claims. Therefore, the embodiments of the invention in which an exclusive property or privilege is claimed are defined in the following appended claims.