BACKGROUND OF THE INVENTION
Present invention relates to a short-shaft training golf club for practicing golf swing in a confined environment, and particularly a method for determining its shaft length and simulating the swing plane of standard golf club.
Developing fundamental golf skills requires constant practicing, which is normally taken place in golf course or driving range. However, author of present invention finds that most fundamental golf skills can be conveniently obtained by practicing golf swing without striking a golf ball in a confined environment such as at home or in office. They include: (1). how to rotate forearms and hinge hand wrist to properly open club face during takeaway, (2). how to position club shaft parallel to ground and parallel to target line with properly-opened club face at the end of takeaway, (3). how to keep club face open to the swing plane after takeaway, and (4). how to develop consistent swing plane, path and temple.
Clearly, practicing golf swing in a confined environment requires a short-shaft golf club that has a shaft length sufficiently shorter than that of standard golf club. By shortening the shaft length, club head can be located closer to the grip. This allows golfer to easily see club face and check if club face is properly opened throughout the entire golf swing. As a result, a short-shaft golf club can be ideal for practicing golf swing.
But the question is how can a golfer determine the swing plane of short-shaft golf club during practicing golf swing? We all know that swing plane of standard golf club is represented by the incline angle of club shaft when golfer addresses golf ball by placing club head immediately behind golf ball and adjacent to ground. When golfer is at address position with a short-shaft golf club, he can't accurately visualize or determine the incline angle of club shaft because club shaft and club head are suspended in air at a relatively high elevation. Without the ability to set the suspended-in-air club shaft at the incline angle identical to that of standard golf club, golfer can't possibly practice golf swing in a swing plane identical to that of standard golf club. As a result, such golf practicing is improper. Clearly, a means for determining the swing plane of short-shaft golf club must be devised before it is used for practicing golf swing.
By analyzing the geometrical relationship between the inclined standard golf club, golfer's feet, hands and eyes at address position, author of present invention devises a graphical method for determining and setting up the short-shaft golf club at the incline angle of standard golf club. The graphical method, which will be discussed in details in later section, is by means of providing a reference marking on ground, and simultaneously determining the shaft length of short-shaft golf club, and the distance between the reference marking and the toe of golfer's shoe at address position. As a result, when golfer is at address position, he can easily set up the incline angle (i.e. swing plane) of short-shaft golf club identical to that of standard golf club by standing away from the reference marking at the predetermined distance, and aiming the suspended-in-air club head at the reference marking on ground.
SUMMARY OF PRESENT INVENTION
An objective of present invention is to provide a short-shaft training golf club for practicing golf swing in a confined environment.
Another objective of present invention is to provide such a short-shaft training golf club with a means for simulating the swing plane of standard golf club.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows the short-shaft training golf club of present invention, with the graphical method for determining its shaft length and simulating the 45 degree swing plane of a standard driver.
FIG. 2 shows the short-shaft training golf club of present invention, with the alternative graphical method for determining its shaft length and simulating the 40 degree swing plane of a standard driver.
FIG. 3 shows the short-shaft training golf club of present invention, with the graphical method for determining its shaft length and simulating the 55 degree swing plane of a standard 7-Iron club.
FIG. 4 shows the short-shaft training golf club of present invention, with the alternative graphical method for determining its shaft length and simulating the 50 degree swing plane of a standard 7-Iron club.
DETAILED DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a graphical method for determining the shaft length of short-shaft training golf club 1 of present invention capable of simulating the swing plane of a standard driver. Short-shaft training golf club 1 has a club head 2 and grip 3 identical to those of standard driver, and a club shaft 4 sufficiently shorter than that of standard driver. Some important input data used in this method are summarized as follows:
(1). Shaft length of standard driver is 45″. (2). Ben Hogan has developed a theory that 1.5″ of grip's butt end of driver shaft shall be extended behind the heel of golfer's shoe when standard driver is laid down on ground with club head aligned to golf ball. (3). Ben Hogan has illustrated that Incline angle of driver shaft is about 45 degree at address position. (4). Ben Hogan has illustrated that an eye-to-thumb line is substantially vertical to ground. (5). Ben Hogan has an average golfer's height at 5′8″, so that his eye location is about 58″ above ground when he is at address position.
In FIG. 1, the graphical method consists of the following steps: (a). plotting an X-Z coordinate in (inch) scale, in which, X axis represents a horizontal ground distance perpendicular to a target line and away from golfer, Z-axis represents a vertical distance above ground, and zero base 0 (0, 0) represents the heel of golfer's shoe when golfer is at address position; (b). locating a point A (43.5, 0) on X-axis to represent the club head of standard driver, in which, 45−1.5=43.5; (c). plotting an 45 degree sloped line AB to represent the standard driver at address position, in which, shaft length of standard driver AB=45; (d). locating a point C in line AB to represent golfer's thumb location on grip 3, in which, BC=7, AC=45−7=38; (e). plotting a vertical line passing through point C to represent an eye-to-thumb vertical line; (f). locating a point D in eye-to-thumb vertical line at elevation=58 to represent the location of golfer's eyes; (g). locating a Point E (28, 0) on X-axis to represent a reference marking E, in which, distance between the reference marking E and the toe of golf's shoe=28−10=18, assuming shoe length is about 10″ from toe to heel; (h). plotting a line DE to represent an eye-to-reference marking line, in which, line DE intersects line AB at point F; (i). measuring the distance between point B and point F (i.e. BF=18) that determines the shaft length of short-shaft training golf club 1 (i.e. shaft length=18 inches); (j). drawing the configuration of club head 2 at point F, in which, incline angle between club shaft 4 and the top line of club head 2 is 120 degree, top width between toe and heel of club head 2 is 5 inches, and height between top line and sole line of club head 2 is 2½ inches; (k). finding out that line DE (i.e. eye-to-reference marking line) intersects club head 2 in an area near by the heel of club head 2.
As a result, when golfer is at address position with the toe of his shoe standing away from reference marking E by 18 inches, he is ready to set up the 18 inch-short-shaft training golf club 1 at the typical 45 degree incline angle of standard driver by aiming the heel of the suspended-in-air club head 2 at reference marking E on ground. By doing so, golfer is ready to simulate the typical 45 degree swing plane of standard driver during practicing golf swing.
FIG. 2 shows an alternative graphical method for determining the shaft length of short-shaft training golf club 5 of present invention capable of simulating the swing plane of standard driver. Short-shaft training golf club 5 has a club head 6 and grip 7 identical to those of standard driver, and a club shaft 8 sufficiently shorter than that of standard driver. The input data used in this alternative method are identical to those used in the graphical method of FIG. 1 with the following exceptions:
(1). Many modern professional golfers including Tiger Wood have illustrated that Incline angle of driver shaft is about 40 degree in lieu of 45 degree at address position. (2). Tiger Wood has illustrated that a chin-to-thumb line in lieu of eye-to-thumb line is substantially vertical to ground. (3). Wood's eye location is at about 60″ above ground and 4″ extended forwardly from his chin at address position.
The alternative graphical method in FIG. 2 consists of the following steps, in which, with exception of steps (c), (e), (f), (i), and (k), all other steps (a), (b), (d), (g), (h) and (j) are the repeated steps of graphical method in FIG. 1: (a). plotting an X-Z coordinate in (inch) scale, in which, X axis represents a horizontal ground distance perpendicular to a target line and away from golfer, Z-axis represents a vertical distance above ground, and zero base O (0, 0) represents the heel of golfer's shoe when golfer is at address position; (b). locating a point A (43.5, 0) on X-axis to represent the club head of standard driver, in which, 45−1.5=43.5; (c). plotting an 40 degree sloped line AB to represent the standard driver at address position, in which, shaft length of standard driver AB=45; (d). locating a point C in line AB to represent the thumb location on grip 7, in which, BC=7, AC=45−7=38; (e). plotting a vertical line passing through point C to represent a chin-to-thumb vertical line; (f). locating a high point in the chin-to-thumb vertical line at elevation=60, and shifting this high point horizontally and forwardly by 4 inch to locate point D representing the location of golfer's eyes; (g). locating a Point E (28, 0) on X-axis to represent a reference marking E, in which, distance between the reference marking E and the toe of golf's shoe=28−10=18, assuming shoe length is about 10″ from toe to heel; (h). plotting a line DE to represent an eye-to-reference marking line; (i). locating a point F in line AB, in which, the 18 inches (BF=18) distance between point B and point F represents the shaft length of short-shaft training golf club 5; (j). drawing the configuration of club head 6 at point F, in which, incline angle between club shaft 8 and the top line of club head 6 is 120 degree, top width between toe and heel of club head 6 is 5 inches, and height between top line and sole line of club head 6 is 2½ inches; (k). finding out that line DE (i.e. eye-to-reference marking line) intersects club head 6 in an area near by the toe of club head 6.
As a result, when golfer is at address position with the toe of his shoe standing away from reference marking E by 18 inches, he is ready to set up the 18 inch-short-shaft training golf club 5 at the typical 40 degree incline angle of standard driver by aiming the toe of the suspended-in-air club head 6 at reference marking E on ground. By doing so, golfer is ready to simulate the typical 40 degree swing plane of standard driver during practicing golf swing.
FIG. 3 shows a graphical method for determining the shaft length of short-shaft training golf club 9 of present invention capable of simulating the swing plane of standard 7-Iron club. Short-shaft training golf club 9 has a club head 10 and grip 11 identical to those of standard 7 Iron, and a club shaft 12 sufficiently shorter than that of standard 7-Iron. Some important input data used in graphical method of FIG. 3 are summarized as follows:
(1). Shaft length of standard 7-Iron is 37 ¼″. (2). Ben Hogan has illustrated that Incline angle of standard 7-Iron is about 55 degree at address position. (3). Ben Hogan has illustrated that, at address position, his eyes, thumb, and toe of his shoe form a sloped line at approximately 80 degree incline angle. (4). Ben Hogan's eye location is about 56″ above ground.
In FIG. 3, the graphical method consists of the following steps: (a). plotting an X-Z coordinate in (inch) scale, in which, X axis represents a horizontal ground distance perpendicular to a target line and away from golfer, Z-axis represents a vertical distance above ground, and zero base O (0, 0) represents the heel of golfer's shoe when golfer is at address position; (b). plotting an 80 degree slopped line passing through the toe of shoe on X-axis at (10, 0); (c). plotting another 55 degree sloped line AB to represent the standard 7-Iron at address position, in which, AB=37¼ represents the shaft length of standard 7-Iron; (d). locating a point C in line AB to represent the thumb location on grip 11, in which, BC=7, AC=37¼−7=30¼; (e). location of sloped line AB as shown in FIG. 3 is determined by a trial method, in which, sloped line AB is shifted back and forth horizontally until point C coincides upon the 80 degree sloped line of (b) above; (f). locating a point D in the 80 degree slopped line of (b) at elevation=56, which represents the location of golfer's eyes; (g). locating a Point E (22, 0) on X-axis to represent a reference marking E, in which, distance between the reference marking E and the toe of golf's shoe is 12 inches (22−10=12), assuming shoe length is about 10″ from toe to heel; (h). plotting a line DE to represent an eye-to-reference marking line; (i). locating a point F in line AB, in which, the 18 inches (BF=18) between point B and point F represents the shaft length of short-shaft training golf club 9; (j). finding out that eye-to-reference marking line DE intersects club head 10 in the area nearby the heel of club head 10.
As a result, when golfer is at address position with the toe of his shoe standing away from reference marking E by 12 inches, he is ready to set up the 18 inch-short-shaft training golf club 9 at the typical 55 degree incline angle of standard 7-Iron by aiming the heel of the suspended-in-air club head 10 at reference marking E on ground. By doing so, golfer is ready to simulate the typical 55 degree swing plane of standard 7-Iron during practicing golf swing.
By applying the above graphical method of FIG. 3 to all other standard iron clubs from 2-Iron to 9-Iron, author of present invention finds that the results of graphical methods of FIG. 3 remain valid for all other standard iron clubs from 2-Iron to 9-Iron. Therefore, it is concluded that, when golfer is at address position with the toe of his shoe standing away from a reference marking E by 12 inches, he is ready to set up the 18 inch-short-shaft training golf club 9 at the typical 55 degree incline angle of any standard iron club by aiming the heel of the suspended-in-air club head 10 at reference marking E on ground. By doing so, golfer is ready to simulate the typical 55 degree swing plane of any standard Iron club during practicing golf swing.
FIG. 4 shows an alternative graphical method for determining the shaft length of short-shaft training golf club 13 of present invention capable of simulating the swing plane of standard 7-Iron club. Short-shaft training golf club 13 has a club head 14 and grip 15 identical to those of standard 7-Iron, and a club shaft 16 sufficiently shorter than that of standard 7-Iron. Some important input data used in this alternative method are summarized as follows:
(1). Shaft length of standard 7 Iron is 37¼″. (2). Most modern professional golfers including Tiger Wood have illustrated that Incline angle of standard 7-Iron is about 50 degree at address position. (3). Tiger Wood has illustrated that, at address position, his eye, thumb, and the front cup head of his shoe form a sloped line at approximately 78 degree incline angle. (4). Wood's eye location is about 56″ above ground at address position.
In FIG. 4, the graphical method for determining shaft length of short-shaft training golf club 13 consists of all the repeated steps of graphical method of FIG. 3. The results of graphical method of FIG. 4 show that, when golfer is at address position with the toe of his shoe standing away from reference marking E by 12 inches, he is ready to set up the 18 inch-short-shaft training golf club 13 at the typical 50 degree incline angle of standard 7-Iron by aiming the toe of the suspended-in-air club head 14 at reference marking E on ground. By doing so, golfer is ready to simulate the typical 50 degree swing plane of standard 7-Iron during practicing golf swing.
Again, by applying the above graphical method of FIG. 4 to all other standard iron clubs from 2-Iron to 9-Iron, author of present invention finds that the results of graphical methods of FIG. 4 remain valid for all other standard iron clubs from 2-Iron to 9-Iron. Therefore, it is oncluded that, when golfer is at address position with the toe of his shoe standing away from a reference marking E by 12 inches, he is ready to set up the 18 inch-short-shaft training golf club 13 at the typical 50 degree incline angle of any standard iron club by aiming the toe of the suspended-in-air club head 14 at reference marking E on ground. By doing so, golfer is ready to simulate the typical 50 degree swing plane of any standard iron club during practicing golf swing.
Patent Application
20170036089
