Patent Publication Number: US-6705952-B1

Title: Golf club with an internal mechanism for measuring the force of a golf swing

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates generally to an accessory for improving a golf swing, and in particular to an accessory having an internal mechanism for measuring the force of a golf swing. 
     2. Description of the Related Art 
     Millions of people enjoy the game of golf. Prior to hitting a golf ball during a game of golf, a golfer must determine the optimal force with which to hit the golf ball, because this will determine the distance the golf ball will travel. Consequently, there is a need for a golf club which allows a user to gauge, before actually hitting the ball, the optimal force with which to hit the golf ball. 
     A variety of golf practice devices are available for improving various aspects of a golfer&#39;s swing. For example, U.S. Pat. No. 4,305,406 to Cromarty appears to show a golf practice device comprised of a number of sensors for determining the position of a head of a golf club during a swing. However, Cromarty provides no information as to the force with which the golfer has swung the club, and therefore does not help the golfer determine how far a golf ball will travel when hit by the head of the golf club. 
     Similarly, U.S. Pat. No. 5,154,427 to Harlan appears to show a golf practice device capable of tracking the real time movement of a golf club during a swing. Harlan, however, also fails to provide any information as to the distance a golf ball will travel after being hit by the head of the club. 
     U.S. Pat. No. 4,146,231 to Merkle appears to show a golf practice device having a platform to assist a player in establishing a proper weight distribution while swinging a golf club. However, Merkle contemplates an apparatus primarily designed to improve a golfer&#39;s stance during the swing, and is not designed to allow a user to estimate the force of the golf swing and the distance a golf ball would travel upon impact. 
     While these units may be suitable for the particular purpose employed, or for general use, they would not be as suitable for the purposes of the present invention as disclosed hereafter. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide a golf club with a mechanism for measuring the force of a swing of the golf club. Accordingly, the golf club has a distance-determining mechanism within its shaft, comprising a movable marker barrel and an associated main spring. During a golf swing, centrifugal force exerted upon the marker barrel causes the marker barrel to move within the shaft, thereby causing the associated main spring to extend. The position of the marker barrel within the shaft is visible to the user, and provides an accurate measure of the force of the swing. 
     It is another object of the invention to produce a golf club which allows a user to estimate the distance a golf ball will travel after being hit by a swing of a golf club of a particular force. Accordingly, the marker barrel moves within the shaft of the club when the club is swung. The position of the marker barrel within the shaft can provide the user with an accurate measure of the distance the golf ball would travel after being hit by a similar swing of the golf club. 
     It is another object of the invention to produce a golf club wherein the marker barrel remains at its extended position after the swing, so that a user may view the position of the marker barrel in order to gauge the force of the swing. Accordingly, the golf club has a release mechanism having a “locked” position, for immobilizing the marker barrel at the extended post-swing position. The release mechanism may subsequently be unlocked by pushing a release button. 
     The invention is a golf club with an internal mechanism for measuring the force of a golf swing, and consequently, the distance a golf ball will travel when hit by the golf swing. The mechanism comprises a marker barrel, an attached distance rod, and an associated main spring. When the golf club is swung, centrifugal force causes the marker barrel and the attached distance rod to be displaced a particular distance within the main spring. The distance of this displacement is limited by the tension that this displacement causes in the main spring. The position of the marker barrel may be seen through circular openings within the shaft. Each circular opening is labeled with indicia indicating the distance a ball would travel had it been hit with the force which caused the marker barrel to move to that position. The golf club additionally has a release mechanism which allows the marker barrel to return to its pre-swing position after the swing is complete. 
    
    
     To the accomplishment of the above and related objects the invention may be embodied in the form illustrated in the accompanying drawings. Attention is called to the-fact, however, that the drawings are illustrative only. Variations are contemplated as being part of the invention, limited only by the scope of the claims. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings, like elements are depicted by like reference numerals. The drawings are briefly described as follows. 
     FIG. 1 is a side view of the golf club. 
     FIG. 2 is a side view of a portion of the golf club before the club has been swung, illustrating the position of the distance rod and marker barrel. 
     FIG. 3 is a side view of a further distal portion of the golf club after the club has been swung, wherein the position of the marker barrel may be readily seen through circular openings within the shaft. 
     FIG. 4 is a side view of the internal mechanisms of the golf club, with portions of the invention broken away to reveal portions of the distance-determining mechanism. 
     FIG. 5 is an enlarged side view detailing the release mechanism. 
     FIG. 6 is a side view of the release mechanism in a released position from the force of a golf swing such that the distance rod and attached marker barrel are allowed to move longitudinally during the golf swing. 
     FIG. 7 is a side view wherein the distance rod and attached marker barrel are permitted to return to their pre-swing positions by pressing a release button to manually release the release mechanism. 
     FIG. 8 is an enlarged side view of the release mechanism as shown in FIG. 7, illustrating how the forward movement of the release sleeve with respect to the collar allows the ball bearing to release the distance rod. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 illustrates a side view of a golf club  10  having a first end  10 A having a handle portion  18 , a second end  10 B having a club head  20 , and an elongated shaft  14  located between the first end  10 A and the second end  10 B. The handle portion  18  and the shaft  14  are substantially hollow and tapered toward the club head  20 . The shaft  14  has an external surface  14 E and an internal bore extending longitudinally substantially between the first end  10 A and second end  10 B. The internal bore is not visible in FIG.  1 . The shaft  14  has a plurality of longitudinally arranged circular openings  16  which extend fully from the external surface  14 E to the internal bore of the shaft  14 . 
     The golf club  10  includes both a distance-determining mechanism and a release mechanism  30  within its substantially hollow shaft  14  and handle portion  18 . FIG. 2 provides a general overview of the position of both these mechanisms within the internal bore of the club  10  in a pre-swing position. The distance-determining mechanism comprises a selectively movable marker barrel  32 , a distance rod  24  rigidly attached thereto, and an associated main spring  34 . The golf club  10  also has a release mechanism  30  for selectively immobilizing the distance rod  24  and the attached marker barrel  32 , both before and after a golf swing. The release mechanism  30  automatically unlocks during a swing from the force of the swing, thereby allowing the distance rod  24  and the attached marker barrel  32  to move within the handle portion  18  and the shaft  14  to a longitudinal position indicative of the force of the swing. 
     FIG. 3 illustrates the club  10  of FIG. 2 shifted to the left to illustrate the marker barrel  32  in a further distal position. Here, the centrifugal force of the swing has displaced the marker barrel  32  and the attached distance rod  24  from the pre-swing position indicated in FIG. 2. A measure of the displacement of the marker barrel  32  within the shaft  14  provides an accurate measure of the force of the swing, and thereby also provides a measure of the distance a golf ball will travel if it were hit by a swing of similar force. The amount by which the marker barrel  32  has been displaced by the swing is readily determined by viewing the position of the marker barrel  32  through the circular openings  16  within the shaft  14  which are provided for this purpose. Indicia label each circular opening  16  with the force of the swing which is necessary to bring the marker barrel  32  to that particular circular opening  16 . Indicia also label each opening  16  with the distance that the golf ball would travel if it were directly hit with a swing of that particular force, or that distance can be determined by the golfer&#39;s experience when simply viewing the relative displacement of the marker barrel  32 . 
     The release mechanism  30  comprises a release nut  26 , a release spring  36 , a collar  40 , a release sleeve  44 , a release tube  22 , and a release button  23 . The position of the collar  40  is fixed within the shaft  14  of the golf club  10 . In FIG. 2, the marker barrel  32  is in its un-extended pre-swing position within the shaft  14 , wherein the distance rod  24  is mostly located between the release mechanism  30  and the handle portion  18 . In this position, a substantial portion of the distance rod  24 , and the entire associated main spring  34 , are obscured by the release tube  22 . The operation of the release mechanism  30  will be described in further detail below. 
     FIG. 4 illustrates both the distance-determining mechanism and the release mechanism  30  prior to swinging the golf club  10 . The distance rod  24  and attached marker barrel  32  are immobilized by the release mechanism  30  in their pre-swing, un-extended position, wherein the distance rod  24  extends substantially within the main spring  34  and release tube  22 . The substantially cylindrical distance rod  24  has a first end  24 A and a second end  24 B. The attached marker barrel  32  also has a first end  32 A and a second end  32 B. Finally, the main spring  34  also has a first end  34 A and a second end  34 B. The first end  32 A of the marker barrel  32  is attached to the second end  24 B of the distance rod  24 . The first end  24 A of the distance rod  24  is attached to the first end  34 A of the main spring  34 . The first end  24 A of the distance rod  24  has a flange  35  for engaging the first end  34 A of the main spring  34  and compressing the main spring  34  as the distance rod  24  moves distally within the club  10 . The second end  34 B of the main spring  34  is attached to the release nut  26  as will be described hereinafter. 
     During a golf swing, centrifugal force is exerted upon the marker barrel  32 . This causes the marker barrel  32  and the attached distance rod  24  to move towards the head  20  of the club  10 . This motion is limited because as the distance rod  24  moves towards the head  20 , the main spring  34  compresses until the centrifugal force which pulls the marker barrel  32  towards the second end  10 B of the club  10  is balanced by the opposing tensional force of the main spring  34  against the release nut  26 . The amount by which the main spring  34  is compressed by the swing, and hence, the distance which the associated distance rod  24  and the attached marker barrel  32  are able to extend during the swing, are directly proportional to the force of the swing. 
     After the swing, the release mechanism  30  automatically locks so that the marker barrel  32  and the distance rod  24  remain at their extended post-swing position within the shaft  14  until the user unlocks the release mechanism  30 , as will be described hereinafter. The user is able to view the position of the immobilized marker barrel  32  within the shaft  14  of the club  10  through the circular openings  16  within the shaft  14 . The marker barrel  32  is brightly colored, so that it may be easily seen through the circular openings  16 . The marker barrel  32  has a plurality of ribs  32 R, each having an associated groove  32 G, so that brightly colored paint on the marker barrel  32  will remain within the grooves  32 G, and will resist “wearing off” even after repeated use of the golf club  10 . 
     The release mechanism  30  has a “release” position and a “lock” position. The release mechanism  30  is “locked” both before and after a swing of the club  10 . The release mechanism  30  is “released” during the swing of the club  10 , in order that the distance rod  24  and attached marker barrel  32  may move freely to their post-swing position within the shaft  14 . FIG. 5 is an enlarged side view taken generally in the area of circle  5  in FIG. 4, with a portion of the collar  40  broken away. Here, the release mechanism  30  is “locked” prior to swinging the club  10 . In the “lock” position, the release mechanism  30  holds the enclosed distance rod  24  and the attached marker barrel  32  immobile within the shaft  14 . 
     The release mechanism  30  has an immobile collar  40  and a selectively movable hollow release sleeve  44  having an external surface  44 E and an internal bore. The release sleeve  44  extends coaxially within the collar  44  and is attached to the release nut  26 . The distance rod  24  selectively extends coaxially within the internal bore of the release sleeve  44 . The internal bore of the release sleeve  44  is not visible in the drawing figures. By virtue of the taper of the shaft  14 , when the release mechanism  30  is installed into the club  10 , the collar  40  becomes wedged within the internal bore of the club  10 , and the position of the collar  40  is fixed within the shaft  14 . The release sleeve  44  has a substantially hemispherical ball seat  50  extending fully from its external surface  44 E to its internal bore. The release mechanism  30  has a spherical ball bearing  38  which rests within the ball seat  50 , which is engaged by the overlying-collar  40 . In FIG. 5, the ball bearing  38  within the ball seat  50  is firmly pressed by the overlying collar  40  against the enclosed distance rod  24  by a camming surface  41  within the collar  40 , thereby immobilizing the distance rod  24  within the release mechanism  30  in its pre-swing position. The release mechanism  30  further comprises a release nut  26  having a first end  26 A and a second end  26 B, a release spring  36  having a first end  36 A and a second end  36 B, and a release tube  22  having a first end  22 A and a second end  22 B. A release button  23  located at the second end  22 B of the release tube  22  is in mechanical contact with the release tube  22 . The first end  34 A of the release spring  34 A is attached to the second end  34 B of the release nut  26 . The second end  34 B of the release spring  34  is attached to the collar  40 . In the absence of an applied force, the release spring  36  biases the release nut  34  away from the collar  40  and thus biases the release mechanism  30  to the locked-position wherein the ball bearing  38  is firmly held against the distance rod  24  by the camming surface  41  of the collar  40 , thereby immobilizing the distance rod  24 . 
     Force exerted upon the release nut  26  in the direction of the marker barrel  32  causes the release mechanism  30  to become “un-locked”, by urging the release nut  34  momentarily toward the immobile collar  40 . There are two origins of this “un-locking” force. Firstly, swinging the club  10  gives rise to a centrifugal force which urges all mass of the release mechanism  30  distally toward the club head  20 . The collar  40  being immobilized, the release nut  26  pushes against the release spring  36  and carries the-release sleeve  44  distally (forward) to a position where it momentarily unlocks the release mechanism  30 . Secondly, pressing the reset button  23 , after the swing is completed, unlocks the release mechanism  30  by causing the second end  22 B of the release tube  22  to press against the first end  34 A of the release nut  34 , thereby urging the release nut  34  and thus the release sleeve  44  rigidly attached thereto momentarily toward the collar  40 , thereby causing the camming surface  41  of the collar  40  to cease pressing the ball bearing  38  against the distance rod  24 , and thereby allows the compressed main spring  34  to expand and bring the distance rod  24  back to its pre-swing position. 
     FIG. 6 illustrates a side view of the distance-determining mechanism and the release mechanism  30  during a swing of the club  10 . The arrow indicates the direction of motion of the marker barrel  32  and attached distance rod  24  during the swing. Here, the release mechanism  30  is unlocked. Centrifugal force exerted upon the release nut  34  by the swing has urged the release sleeve  44  forward, thereby relieving the ball bearing  38  from the pressure exerted against the distance rod  24  by the collar  40 , so that the ball bearing  38  no longer presses against and immobilizes the distance rod  24  and the attached marker barrel  32 . 
     During the swing, the marker barrel  32  slides toward the head  20  of the club  10  until the centrifugal force of the swing is exactly balanced by the tension that this swing causes within the main spring  34 . The distance rod  24  remains at this extended “post-swing” position because the release mechanism becomes “locked” at the zenith of the swing, when the opposing forces on the release nut  34  are balanced. The user is able to determine the force of the swing by reading calibrations which are associated with the circular openings  16 . 
     FIG. 7 illustrates a side view of the distance rod  24  and attached marker barrel  32  returning to their pre-swing position, after the release mechanism  30  has been unlocked by pressing the reset button  23 . An arrow adjacent to the release button  23  indicates the direction in which the release button  23  is pressed by a user. An arrow adjacent to the marker barrel  32  indicates the direction of motion of the marker barrel  32  after the release button  23  is pressed. Pressing the reset button  23  causes the underlying release tube  22  to push the release nut  34  forward toward the collar  40 , compressing the attached release spring  36 , thereby urging the release sleeve  44  toward the head  20  of the club  10 . This causes the release sleeve  44  to move forward within the immobile collar  40 , thereby allowing the ball bearing  38  to move slightly away from the enclosed distance rod  24 , and thus releases the distance rod  24 , so that the main spring  34  returns the marker barrel  32  to the pre-swing position, and “resets” the club  10  for the next use. 
     FIG. 8 illustrates an enlarged side view of the release mechanism  30 , with a portion of the collar  40  broken away. Here, it is detailed how the release tube  22  is pushing the release sleeve  44  forward so that the ball bearing  38  is not pressed against the distance rod  24  by the camming surface  41  of the collar  40 , and the distance rod  24  and attached marker barrel  32  are able to retract back to their pre-swing position by the tension within the compressed main spring  34 . 
     In use, a user determines how far he/she would like to hit the golf ball on a particular occasion. The user then takes a practice swing with the golf club  10 , wherein the golf ball is not hit. After the practice swing, the user determines the force of the practice swing, and the distance a golf ball would have traveled had it been hit by a swing of similar force to that of the practice swing, by viewing the position of the marker barrel  32  through one of the openings  16  through the shaft  14 , and by ascertaining the associated force and distance from indicia surrounding the opening  16  which is adjacent to the marker barrel  32 . The user unlocks the release mechanism  30  after each practice swing by pressing on the release button  23 . The user repeats the practice swing, until the position of the marker barrel  24  within the shaft  14  indicates that the ball will travel the desired distance upon being hit by a swing of similar force. Now, armed with the knowledge of how hard to hit the ball, the user is ready to actually hit the ball. 
     In conclusion, herein is presented a golf club with an internal mechanism for measuring the force of a golf swing. The invention is illustrated by example in the drawing figures, and throughout the written description. It should be understood that numerous variations are possible, while adhering to the inventive concept. Such variations are contemplated as being a part of the present invention.