Abstract:
An extensible exercise golf club including a golf club shaft comprising a plurality of telescopic interlocking shaft lengths which function to extend from a collapsed position to a fully extended position as a result of the force generated by the swinging action of the golf club and automatically return to the collapsed position by the force of vacuum generated within the shaft as the shaft sections are telescopically extended.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an extensible exercise golf club for training golfers and more particularly, to an exercise golf club which includes a plurality of telescopic interlocking tubular shaft lengths containing a vacuum space disposed therein for causing the telescoped shaft lengths to extend from a collapsed position to a fully extended position and then to collapse from the extended position to a fully collapsed position as a result of the force generated by the vacuum space. Thus, beginning golfers can learn to swing a golf club very easily with very little effort, thus effectively reducing the training period. 
     2. Description of the Prior Art 
     Several types of collapsible golf clubs are known in the art. For example, such golf clubs include those which possess adjustable shaft lengths; means for varying the grip of golf clubs axially collapsible shafts, and the like. However, such collapsible golf clubs suffer from many problems. For example, it is difficult for a beginning golfer to timely hit a golf ball using such golf clubs and to properly control the power transferred from the legs of the golfer to a golf club head. Such golf clubs are described in U.S. Pat. No. 2,107,983 to Hamilton, U.S. Pat. No. 2,214,079 to Horton, U.S. Pat. No. 2,772,887 to Blake, U.S. Pat. No. 3,070,370 to Steiner, U.S. Pat. No. 3,102,726 to Barrett, U.S. Pat. No. 3,214,170 to Warnock, U.S. Pat. No. 3,524,646 to Wheeler, U.S. Pat. No. 3,528,660 to Kategian, U.S. Pat. No. 3,539,185 to Andis, U.S. Pat. No. 3,663,019 to Palotsee, U.S. Pat. No. 3,829,092 to Arkin, U.S. Pat. No. 3,840,231 to Moore, U.S. Pat. No. 4,343,473 to Laursen, U.S. Pat. No. 4,674,747 to Mazzocco et al. 
     In order to avoid such problems, U.S. Pat. No. 4,931,661, issued to the present inventor, describes an extensible exercise golf club including a golf club shaft comprising a plurality of telescopic tubular members which telescopically fit into each other for slidably extending from a telescopically collapsed position to a telescopically extended position. Channel and rail members are disposed alternately on the inner and outer surfaces of adjacent telescopic tubular members, whereby the rail member of one tubular member engages the channel member of an adjacent tubular member for interlocking the adjacent telescopic tubular members together. Thus, upon swinging the golf club, the club shaft member of the golf club is guided by the engagement of the rail members within the channel members whereby the twisting of adjacent shaft members is effectively prevented. 
     However, this extensible exercise golf club is complicated in structure and expensive to manufacture. Furthermore, in order to collapse the extended telescopic tubular shaft members, the golfer has to utilize force to push the tubular shaft members, which takes time in its operation. Sometimes, if the channel and rail members become broken, the extensible exercise golf club cannot be used and thus it becomes uneconomical. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide an improved extensible exercise golf club for use in training golfers. 
     Another object of the present invention is to provide an extensible exercise golf club which includes a plurality of concentric, telescopic interlocking tubular light shaft lengths containing a vacuum space disposed therein which extends from the handle member. 
     A further object of the present invention is to provide an extensible golf club which is further provided with a pseudo-ball containing a weight member disposed therein and attached to the heel shaft thereof, whereby the golfer can swing freely. 
     Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
     Briefly described, the present invention relates to an extensible golf club including a golf club shaft which comprises a plurality of telescopic interlocking shaft lengths and a vacuum space disposed therein, and a golf ball containing a weight member attached to the end of the shaft whereby the shaft extends from a collapsed position to a fully extended position as a result of the force generated by the swinging action of the golf club. The shaft then collapses from an extended position to a fully collapsed position as a result of the vacuum force generated in the vacuum space by the extension of the shaft members. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
     FIG. 1 is a perspective view of an extensible golf club according to the present invention in a fully collapsed position, showing in cut away portions thereof the basic components of the present invention; 
     FIG. 2 is a perspective view of the extensible club according to the present invention in a fully extended position; 
     FIG. 3 is a sectional view of FIG. 2, taken along line 3--3, showing the enlarged connecting portions of a tubular shaft length; 
     FIG. 4 is a cross-sectional view of FIG. 1, taken along line 4--4; and 
     FIG. 5 is a pictorial view, showing a golfer using the extensible golf club according to the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now in detail to the drawings for the purpose of illustrating preferred embodiments of the present invention, the extensible exercise golf club as shown in FIGS. 1, 2, and 3 comprises an extensible shaft 10 defining a plurality of concentric, telescopically interlocking tubular shaft lengths 11a, 11b, and 11c, a pseudo-golf ball 13 containing a ball weight member 14 disposed at one end of the shaft and a cap 15 disposed at the other end of the extensible shaft 10. That is, the pseudo-golf ball 13 is provided at the end portion of the tubular shaft length 11c and the cap 15 is provided at the top of the tubular shaft length 11a, with the shafts defining a space 17 disposed in the tubular shaft lengths 11a, 11b, and 11c. 
     The tubular shaft length 11a is provided with a typical golf club grip member 12 disposed therearound for permitting a tight grasp of the golf club. The ball weight member 14 has an aperture 16 to facilitate its attaching to the end portion of the tubular shaft length 11c with a strong adhesive 16a as shown in FIG. 3. The ball weight member 14 is made of steel, rubber, or the like to add weight to the pseudo-golf ball 13. 
     As shown in FIG. 3, the telescopic interlocking tubular shaft lengths 11a, 11b, and 11c contain extended raised portions 111a, 111b, 111c, and 111d which operatively interlock with each other at the end openings of the shaft lengths. 
     Accordingly, when the telescopic interlocking tubular shaft lengths 11a, 11b, and 11c are fully extended by the force of the swing of the player, the extended raised portions 111a and 111b, and 111c and 111d are tightly interlocked. At this time, a vacuum is generated in the space 17 of the telescopic interlocking tubular shaft lengths 11a, 11b, and 11c (FIGS. 2 and 3). Accordingly, when the swing of the golfer is finished, the fully extended tubular shaft lengths 11a, 11b, and 11c are caused to immediately collapse by the vacuum generated in the space 17 of tubular shaft lengths 11a, 11b, and 11c (FIGS. 1 and 4). 
     In assembly, first of all, the shaft length 11c is slidably inserted into the shaft length 11b so that the raised portion 111c of the shaft length 11c interlocks with the raised portion 111d of the shaft length 11b. Thus, the shaft length 11b is engaged with the shaft length 11c (FIG. 3). Thereafter, the shaft length 11b which is engaged with the shaft length 11c is slidably inserted into the shaft length 11a so that the raised portion 111b of the shaft length 11b interlocks with the raised portion 111a of the shaft length 11a. Thus, the shaft length 11a is engaged with the shaft length 11b (FIG. 3). 
     Afterwards, the cap 15 is placed on the end opening of the shaft length lla and the grip member 12 is provided around the upper portion of the shaft length 11a (FIG. 3). Thereafter, the pseudo-golf ball 13 containing the weight member 14 is attached to the lower end portion of the shaft length 11c by inserting the shaft member into the aperture 16 of the ball 13 with the strong adhesive 16a (FIGS. 1 and 3). The weight member 14 is steel, rubber, or the like. 
     In operation, as shown in FIG. 5, when a golfer swings forward, the golf club is gradually extended in the direction indicated by arrows (a), (b), (c), (d), (e), (f), and (g) from a collapsed position (A) to the extended position (B). At that time, the pseudo-golf ball 13 rhythmically hits a point disposed on the ground 20 and the golfer can swing with very little effort being required by the golfer. 
     Accordingly, the extensible shaft lengths 11a, 11b, and 11c of the exercise golf club are slidably and frictionally engaged with each other so that the force of the swing overcomes the frictional engagement for freely extending the club shaft during the swinging operation of the golf club for striking the ground 20. 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included in the scope of the following claims.