Abstract:
A modular golf club includes a head, a top shaft and a connector shaft between the head and the top shaft. The connector shaft has a couple of identical fastening means at both ends thereof. The fastening means is an insertion tip in the shape of regular hexagon and a union nut secured to the connector shaft slidably but with a limit defined by a radial flange at the base of the hexagonal tip. Either union nut has an inner thread toward its outer end the diameter of which is bigger than the flange to allow the union nut to be positioned over the hexagonal tip in a juxtaposed relationship.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     A. Field of the Invention  
         [0002]     The present invention relates to golf clubs. More particularly the present invention relates to a modular golf club that enables golfers to carry less.  
         [0003]     B. Description of the Prior Art  
         [0004]     Golf is a game of precision played with a golf ball and a set of clubs on a grass course with a number of holes into which the ball must drop with preferably lesser stokes. Players seek to reduce stroke numbers and prefer to pick the best club for each stroke. Different clubs have different loft, distance and trajectories. The general caddieless players must carry all, fourteen or so clubs in a bulky golf bag about the course for hours.  
         [0005]     Ideas of having a common club shaft share variety of head sections have been publicized. U.S. Pat. No. 6,547,673 to Roark incorporated herein by reference shows an interchangeable modular golf club head and adjustable handle system. Other U.S. Pat. Nos. 6,723,000 and 6,663,502 incorporated herein by reference also show interchangeable club heads. Unfortunately, because golf is a precision sport, the interchangeable system requires a firm connection. Because players cannot have unlimited time on the course, the interchange must also be quick and preferably without tools.  
       SUMMARY OF THE INVENTION  
       [0006]     In view of the foregoing, it is an object of the present invention to provide a modular golf club, be it a putter, a wood, a wedge or an iron that provides an in-line and integral connection in a simpler way of sharing multiple golf heads. Another object of the present invention is to provide a modular golf club connection with virtually no addition of bulkiness or excess mechanism.  
         [0007]     According to the present invention, a golf club comprises a head, a top shaft and a connector shaft between the head and the top shaft. The connector shaft has a couple of identical fastening means at both ends thereof. In one embodiment of the present invention, the fastening means is an insertion tip in the shape of regular hexagon and a union nut secured to the connector shaft slidably but with a limit defined by a radial flange at the base of the hexagonal tip. Either union nut has an inner thread toward its outer end the diameter of which is bigger than the flange to allow the union nut to be positioned over the hexagonal tip in a juxtaposed relationship.  
         [0008]     To restrain the movement of the union nut on the connector shaft, the nut has its inner end an annular shoulder with a smaller diameter than that of the flange.  
         [0009]     Identical receiving ends are provided distally at both the top shaft and the head units. Either receiving end is comprised of a hexagonal slot to receive and nonrotatably lock one of the hexagonal tips of the connector shaft and an outer thread which may be engaged with one of the union nuts to fasten the modular club members axially securely. Therefore, a speedy double fastening means is provided according to the present invention in order to interconnect the common golf shaft upper section and the various club heads such as a series of iron heads with high integrity.  
         [0010]     The simplified intuitive method of the inventive golf club modules needs the golfers fasten one nut of the connector shaft to the top shaft section just once at a course and allows interchanges through the club lineup with turning the other nut one way or another on the selected club heads.  
         [0011]     The present invention avoids to add the excessive contraptions to the conventional shaft profile only to make the replaceable club heads theoretically possible which will counteract the beneficial realization of having one common club shaft to master many golf heads explaining the reason behind no practical such clubs having been accepted with popularity yet.  
         [0012]     Among others, a practical benefit of the present invention will be that no rattling along the entire length of the modular club should be concerned thanks to the unique structural feature requiring lesser components and giving more integrity to the resultant clubs.  
         [0013]     Embodiments of the invention will now be described by way of example with reference to the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]      FIG. 1 a  perspective view of the modular golf club according to the present invention.  
         [0015]      FIG. 2  is an exploded perspective view of the component parts for a wood with the improved connection according to one embodiment of the invention.  
         [0016]      FIG. 3  is a part-sectional front view of the club of  FIG. 1  showing the club parts and mode of connections in detail.  
         [0017]      FIG. 4  is a view of an alternate embodiment.  
         [0018]      FIG. 5  is a view of an alternate embodiment. 
     
    
       [0019]     Similar reference numbers denote corresponding features throughout the attached drawings.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0020]     With reference to  FIG. 1 , a connector shaft  10  is shown in position between a top shaft  11  and a neck or hosel  12  of a club head  13 , which is a replaceable wood with any one of irons, wedges, and a putter in the individual golfer&#39;s roster of clubs. The top shaft  11  has a typical design at its upper portion to have a general cylinder body topped with a grip and a cap not shown, as they are well known in the field. The lower end of the top shaft  11  is shaped to make the novel union with the connector shaft  10  through one of a couple of union nuts  14  and  14 ′. The golf club sections are locked in radial orientation around the shaft as well as longitudinal orientation that is parallel to the club shaft.  
         [0021]     The wood head  13  as used for long-distance strokes by the golfer for tee shots has a longer predetermined neck or hosel than those of the irons, wedges, and putter for shorter-distance strokes in the respective specific circumstances of the course. So the wood is the longest club and iron, wedge and putter become shorter in this order. To keep the user operation as well as the manufacture of the inventive golf club modules intuitively simple, the top shaft  11  and then its assembly with the connector shaft  10  remains a common component of the golf club. Even the neck or hosel  12  of the head  13  is terminated with an identical shape to that of the lower end of the top shaft  11  to make another novel union with the union nut  14  or  14 ′.  
         [0022]     For example, the top shaft  11  may be nineteen inches long and the connector may be seventeen inches to make a thirty six inch shaft of an iron. The variation requirements between the irons and other types of clubs then can be met by varied neck lengths specified for the respective club heads which can be realized by the current manufacturing facilities. The connection thus has means preventing the twisting of the shaft as well as the bending of the shaft as well as pulling of the shaft away from the club head. This is shown in the following drawings.  
         [0023]     Referring now to the connector shaft  10  shown in  FIGS. 2 and 3 , it is clear how shaft  10  can interconnect the top shaft  11  and the club head  13 . The shaft  10  works as a lower extension of the top shaft  11  while serving its connection duty with the head  13 . The shaft  10  is comprised of a body  110  which is generally cylindrical but its opposite ends formed with a couple of identical hexagonal tips  15  and  15 ′. The hexagonal tips  15  and  15 ′ have converging points  16  and  16 ′ for insertions to the top shaft  11  and the neck or hosel  12 , respectively. To receive the tips  15  axially into the shaft  11 , it has a blind opening or corresponding hexagonal slot  17  into which the point  16  leads the tip  15  into non-rotatable locking engagements between the shafts  11  and  10 . The converging point  16  forms a face  160  preventing bending motion. The convergent tip and face should be long enough to prevent mending motion.  
         [0024]     A radial flange  18  is provided at the base of the hexagonal tip  15  acting as a stop abutting the bottom of the shaft  11 . Radially outward of the slot  17  is formed a threaded end  19  on the shaft  11  to allow a secondary locking means to achieve rigidity in the connection of the modular golf club. A couple of union nuts  20  and  20 ′ formed as internally threaded collars are slidably attached on the cylindrical body  110 . Union nuts  20  and  20 ′ have identical structure wherein a nut  20  has an inner thread  120  at its open end toward the corresponding tip  15  of the shaft  10  and at its opposite end an annular shoulder  121  with an inner diameter to slide up and down over the outer diameter of the body  110 . However, the nut  20  is limited to slide up to the flange  18  where it stops in a juxtaposed relationship to each other while the identical nut  20 ′ is slid down to the flange  18 ′ into the similar limited position. The shoulder  121  has its inner diameter set so that it slides on the body  110  between the opposite flanges  18  and  18 ′.  
         [0025]     The body may be made of a metal pipe cut to length which is then plugged by end pieces of the tips  15  and  15 ′ formed with flanges  18  and  18 ′ having two opposing union nuts  20  and  20 ′ fitted thereon as is depicted on the drawings.  
         [0026]     Also, the cylindrical body  110  and the tips  15  and  15 ′ with flanges  18  and  18 ′ may be a solid one piece made of a light weight material with an appropriate surface finish and the union nuts  20  and  20 ′ may either be metal or plastic components which can be subsequently assembled onto the body  110  according to the present invention. In this case, the nuts  20  and  20 ′ can be machine pressed onto the body  110  over the flanges  18  and  18 ′, which will then limit the nut movement therebetween.  
         [0027]     In taking such construction of golf club modules of the present invention out to the course, the top shaft  11  may be carried with the connector shaft  10  in a light weight bag for field assembly into an integral shaft component using the union nut  20  leaving the other nut  20 ′ free for mating with the golfer&#39;s choice of head. Depending on the distance to cover and the particular situation, players choose a club with the appropriate characteristics. Choosing a club will be as fast as interchanging the desired heads with the complement of tightening one nut  20 ′ over the club head of choice. Except the only sliding part of the nut  20 ′ that will be screw tightened on the head  12 , there are provided no parts to move or rattle even under excessive force of hit or mishit throughout the club of the present invention.  
         [0028]     Because the differentiation in club length has been built into the neck sizing in the respective heads, only the nut  20 ′ is left to handle at the golfer&#39;s end to achieve the high speed and integrity of the modular golf club through the connector shaft of the present invention.  
         [0029]     The nut  20  is shown as a smooth circular profile cylindrical member, but can also have at least one of a thumb and/or forefinger protrusions as in a win nut allowing easy hand tightening. The protrusions or protrusion can be made detachable. The nut  20  formed as a collar is preferably made of metal allowing secure connection between the shaft and head preventing pulling of the shaft away from the head during ball striking. The nut  20  can also be formed as a hexagonal profile allowing a wrench tool for changing club head and shaft. Although a hexagonal protrusion is preferred, any non-circular cross section protrusion can be used.  
         [0030]      FIG. 4  shows an alternate embodiment where the shaft  11  is directly connected to the protrusion  15  that is connected to the slot  17 . The connection means is analogous to the primary embodiment where the collar nut  14  secures over the threaded portion  19 . Having a single connection is better than having the double connection because it decreases complexity, cost and chance for malfunctions during ball striking. The alternate embodiment would not allow a variety of different shafts having varying lengths and characteristics. In the primary embodiment as shown in figure two, the shaft  110  can be made in a variety of different characteristics, varying in flexibility, lengths, weight and color. Also, the primary embodiment has the benefit of different styles of grips that can be interchanged without changing the shaft.  
         [0031]      FIG. 5  shows an alternate embodiment where the connection means is reversed. In this case, the hosel  12  has a protrusion  15  and the shaft has a slot receiving the protrusion  15 .  
         [0032]     It is to be understood that the present invention is not limited to the sole embodiment describe above, but encompasses any and all embodiments within the scope of the following claims. One of the equivalent connection means is reversing the connection at the club head and shaft so that the club head provides a non-circular protrusion and nut engaging with a shaft having a hole adapted for the non-circular protrusion and having thread allowing the nut to be attached.