1. Field of the Invention
The present invention relates to an apparatus that assists in selecting a shaft for a golf club.
2. Description of the Related Art
In recent years, a tendency among golfers to want golf clubs more suitable for them is growing. Hence, a method of measuring the head speed and struck ball data upon a test strike, and selecting a golf club in accordance with the measurement results (for example, Japanese Patent Laid-Open No. 2003-102892), etc. have been proposed. A tendency to want parts of a golf club, which are individually, exclusively suitable for each golfer, is also growing, and many golfers want especially shafts suitable for them. Hence, a golf club with an easily exchangeable shaft (for example, Japanese Patent Laid-Open No. 2009-178296), etc. have also been proposed.
A wide variety of shafts have been distributed to the market, so it is becoming important for golf shops to carefully select and recommend shafts suitable for individual golfers. In the conventional recommended shaft selection, it is often the case that shafts are classified mainly in accordance with their flexes (stiffnesses), and shafts with flexes corresponding to individual golfers are selected and recommended in consideration of, for example, their head speeds. However, even shafts with nearly the same flex may give greatly different swing feels and produce greatly different test strike results, so a new method of selecting a recommended shaft is required.
It is an object of the present invention to select shafts suitable for individual golfers.
According to an aspect of the present invention, there is provided a shaft selection assist apparatus comprising storage means for storing recommended shaft information indicating a correspondence between measurement parameters obtained upon a test strike with a golf club to which a predetermined reference shaft is attached, and recommended shafts among shafts of a plurality of types, acquisition means for acquiring measurement results of the measurement parameters associated with a test strike actually made by a user with the golf club, selection means for selecting a recommended shaft by referring to the recommended shaft information based on the measurement results acquired by the acquisition means, and output means for outputting information indicating the recommended shaft selected by the selection means, wherein the recommended shaft information stored in the storage means comprises information which specifies recommended shafts based on a relationship between a shaft rigidity distribution and the measurement parameters.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
<Apparatus Arrangement>
The CPU 101 executes a program associated with shaft selection assistance (to be described later). This program is stored in the HDD 105. Also, the HDD 105 accumulates data necessary to execute this program, such as recommended shaft information and individual shaft information (to be described later). Each of the ROM 102, RAM 103, and HDD 105 may be a storage means of another type.
The interface 104 is interposed between an external device and the CPU 101 to allow the CPU 101 to output data to an external device and allow the external device to input data to the CPU 101. Interfaces 104 suitable for individual external devices can be provided.
An input device 110 includes, for example, a keyboard and a pointing device such as a mouse. The CPU 101 can acquire information and an instruction, which are input to the input device 110, via the interface 104. A display 120 displays various kinds of information as electronic images in accordance with instructions from the CPU 101. The CPU 101 performs, for example, display control of the recommended shaft selection result via the interface 104.
The assist apparatus 100 according to this embodiment is connected to a measuring device for measuring various kinds of measurement parameters upon a test strike. In this embodiment, the measuring device includes a pair of sensors 131 and a pair of cameras 132. A test strike is made by actually striking a golf ball 200, supported on a tee 210, assuming a direction d1 indicated by an arrow as the flight trajectory direction (target direction). A mark 201 for measuring data on a struck ball is formed on the surface of the golf ball 200.
The sensor 131 is a photosensor including, for example, a light-emitting element and light-receiving element. The pair of sensors 131 are arranged slightly behind the tee 210 in the direction d1 with a spacing from the tee 210 in a direction perpendicular to the direction d1, and are spaced apart from each other in a direction parallel to the direction d1. Each of the pair of sensors 131 detects passage of a golf club head.
The pair of cameras 132 are arranged slightly in front of the tee 210 in the direction d1 with a spacing from the tee 210 in a direction perpendicular to the direction d1, and are spaced apart from each other in a direction parallel to the direction d1. Each of the pair of cameras 132 captures an image of a struck ball (golf ball 200).
Data on the detection result obtained by the sensor 131 and on the image captured by the camera 132 are read into the assist apparatus 100. The CPU 101 measures the time from when the sensor 131 on the rear side in the direction d1 detects passage of a golf club head until the sensor 131 on the front side in this direction detects passage of the golf club head. The CPU 101 can then calculate the head speed from the measured time and the known distance between the pair of sensors 131.
The CPU 101 can also calculate the back spin amount on a struck ball, the side spin amount and side spin direction on this ball, and the vertical and horizontal launch angles of this ball based on the images captured by the pair of cameras 132. These values can be calculated based on changes in position and orientation of the mark 201 included in the captured images, the image capturing timings, and the distances between the pair of cameras 132.
The back spin amount can be calculated from the amount of vertical pivoting, the side spin amount and direction can be calculated from the amount of horizontal displacement of the mark 201, and the vertical launch angle can be calculated from the amount of vertical displacement of the mark 201. The horizontal launch angle can be calculated from a change in size of the mark 201. As shown in the image IMG2, when the mark 201 is smaller than that in the image IMG1, the ball 200 is launched horizontally, so the launch angle can be calculated based on the degree of horizontal launch.
<Shaft Rigidity Distribution>
In this embodiment, a plurality of shafts are classified based on their rigidity distributions, and a recommended shaft is selected from them. First, the shaft rigidity distribution will be described.
In the shaft 11, the side of the head 12 will be called a distal end, and the grip 13 will be called a proximal end. Normally, the shaft 11 has a rigidity (Young's Modulus×Cross-sectional Second-order Moment) which gradually increases from the distal end to the proximal end. However, the rigidity of the shaft 11 does not always increase linearly, and increases with characteristics which differ depending on its type.
The present invention focuses attention on the fact that the shaft rigidity distribution influences a swing and a struck ball. In this embodiment, shafts are classified especially based on the distal rigidity difference and proximal rigidity difference among various types of shaft rigidity distributions, and a recommended shaft is selected.
The distal rigidity difference means the rigidity difference in a predetermined range of the shaft on the distal side, and corresponds to a rigidity difference D1 between the two ends of a range P1 in
The inventors of the present invention conducted an experiment, and concluded that the golfer is likely to feel that the distal end of the shaft is soft during a swing when the distal rigidity difference is large, whereas he or she is likely to feel that the distal end of the shaft is stiff during a swing when the distal rigidity difference is small. Also, we concluded that the golfer is likely to feel that the proximal end of the shaft is stiff during a swing when the proximal rigidity difference is large, whereas he or she is likely to feel that the proximal end of the shaft is soft during a swing when the proximal rigidity difference is small. Hence, a shaft suitable for the tendency of a swing or struck ball for the golfer can be recommended to him or her in consideration of such shaft rigidity distributions.
<Shaft Classification>
In this embodiment, shafts are classified into four groups I to IV in accordance with the distal rigidity difference and proximal rigidity difference.
<Test Strike>
In recommended shaft selection, the user actually makes a test strike using a golf club to which a predetermined reference shaft is attached, and the measurement results of specific measurement parameters are used. In this embodiment, the head speed, the side spin amount and direction on a struck ball, and the horizontal launch angle of this ball are used to select a recommended shaft. The CPU 101 of the assist apparatus 100 reads the detection results obtained by the pair of sensors 131, and the images captured by the pair of cameras 132, calculates the measurement result of each measurement parameter, and stores them in the HDD 105. The measurement result of each measurement parameter preferably is its average obtained upon a plurality of times of test strikes.
The reference shaft for use in a test strike desirably has a rigidity distribution with little unevenness, such as the one which belongs to a region surrounded by a broken line in
<Shaft Selection Assist Process>
A shaft selection assist process executed by the CPU 101 of the assist apparatus 100 will be described next with reference to
In step S1, the measurement results of measurement parameters obtained upon a test strike are acquired. In this embodiment, the measurement results obtained upon a test strike are stored in the HDD 105. Thus, the measurement results are acquired by reading them out from the HDD 105. Assume that although the user made a test strike in the past, the measurement results obtained upon the test strike are not stored in the HDD 105 and are only known to the user. In this case, the user manually inputs the measurement results from the input device 110, and the CPU 101 receives the input data, thereby acquiring them. Also, assume that the assist apparatus 100 has a network interface and can be connected to a network such as the Internet. In this case, the CPU 101 may receive the input data indicating the measurement results via the network, thereby acquiring them.
In step S2, a recommended shaft is selected. This process is performed by referring to recommended shaft information stored in the HDD 105 in advance, based on the measurement results acquired in step S1.
The recommended shaft information indicates a correspondence between measurement parameters obtained upon a test strike using a golf club to which a reference shaft is attached, and recommended shafts among shafts of a plurality of types. In this embodiment, the recommended shaft information specifies recommended shafts based on the relationship between the shaft rigidity distribution and the measurement parameters, as will be described below.
In this embodiment, the recommended shaft information indicates a correspondence between the side spin amount and direction and the horizontal launch angle, and groups of recommended shafts, as shown in
In the example shown in
The swing trajectory and the orientation of the face surface at the time of impact, and the shaft rigidity distribution can be evaluated to have the following relationship. First, a user who produces an inside-out swing trajectory tends to swing a golf club with a so-called late hit. Hence, the use of a golf club having a shaft with a tight proximal side allows this user to easily have a swing, so a shaft with a stiff proximal end is suitable for him or her. Conversely, a user who produces an outside-in swing tends to swing a golf club with little so-called late hit. Hence, the use of a golf club having a shaft with a flexible proximal side allows this user to easily have a swing, so a shaft with a soft proximal end is suitable for him or her.
A user who closes the face at the time of impact preferably does not make the head travel at the time of impact from the viewpoint of preventing the formation of a trajectory line with a strong hook. Hence, a shaft with a stiff distal end is suitable for this user. Conversely, a user who opens the face at the time of impact preferably makes the head travel at the time of impact from the viewpoint of preventing the formation of a trajectory line with a strong slice. Hence, a shaft with a soft distal end is suitable for this user.
Referring to
Region C corresponds to a left launch angle and slice side spin. Hence, a shaft with both a soft proximal end and distal end is suitable for region C, so group III is associated with region C as recommended shafts. Region D corresponds to a left launch angle and hook side spin. Hence, a shaft with a soft proximal end and a stiff distal end is suitable for region D, so group IV is associated with region D as recommended shafts.
In the process of step S2, the CPU 101 specifies one of regions A to D, to which the user belongs, from the measurement results of the horizontal launch angle and side spin direction acquired in step S1. Next, the CPU 101 specifies a shaft group corresponding to the specified region among groups I to IV. Moreover, the CPU 101 specifies the flex of a shaft suitable for the user from the head speed acquired in step S1. For example, the CPU 101 specifies R if the head speed is less than 42 m/s, S if the head speed is 42 m/s (inclusive) to 47 m/s (exclusive), and X if the head speed is 47 m/s or more.
The CPU 101 selects a shaft, which belongs to the specified group and flex, as a recommended shaft by referring to the shaft classification information shown in
Although the group specification and the flex specification are performed in this order in this embodiment, they may be performed in reverse order. Also, although the recommended shaft information and the shaft classification information are separately stored in the HDD 105 in this embodiment, they may be combined into recommended shaft information.
Referring back to
In this manner, in this embodiment, shafts more suitable for individual golfers can be selected by selecting recommended shafts in consideration of the shaft rigidity distributions. Especially because the horizontal launch angle and the side spin direction are associated with the shaft rigidity distribution, a shaft suitable for the swing trajectory of a golfer as the user and his or her habit in terms of how to move the face at the time of impact can be recommended to him or her. In this embodiment, users are classified in accordance with both the horizontal launch angle and the side spin direction, and shafts are also classified in correspondence with these parameters. However, for example, users may be classified in accordance with only the horizontal launch angle, and shafts may also be classified in correspondence with this parameter. Alternatively, users may be classified in accordance with only the side spin direction, and shafts may also be classified in correspondence with this parameter.
Although users are classified in accordance with the horizontal launch angle and the side spin direction in the first embodiment, they may be classified in accordance with other measurement parameters. Also, it is often the case that intermediate/advanced golfers strike balls with both small side spin amounts and horizontal launch angles, so the use of only the horizontal launch angle and the side spin direction is insufficient to appropriately classify users and shafts. In view of this, in this embodiment, a recommended shaft is selected using two types of recommended shaft information which adopt different measurement parameters.
In step S12, region determination is performed. In this case, the users who have made test strikes are classified using recommended shaft information shown in
Referring back to
In step S15, a recommended shaft is selected based on recommended shaft information shown in
In the example shown in
The vertical launch angle serves as an index which determines the swing trajectory of the user who has made a test strike. In other words, this trajectory can be evaluated such that an upper blow swing trajectory is produced if the vertical launch angle is large, and a down blow swing trajectory is produced if the vertical launch angle is small. Also, the back spin amount serves as an index which determines whether the user who has made a test strike tends to largely turn his or her hands at the time of impact (tends to rotate the face). In other words, this tendency can be evaluated such that the user turns his or her hands only a small amount if the back spin amount is large, and the user turns his or her hands significantly if the back spin amount is small.
The swing trajectory and the tendency to or not to largely turn hands, and the shaft rigidity distribution can be evaluated to have the following relationship. First, a user who produces an upper blow swing trajectory tends to be incapable of making the head travel at the time of impact upon delaying the head, that is, flexing the proximal side of the shaft because he or she cannot make a late hit upon a down swing. Hence, the use of a golf club having a shaft with a flexible proximal side allows this user to easily have a swing while making a late hit upon a down swing, so a shaft with a soft proximal end is suitable for him or her. Conversely, a user who produces a down blow swing trajectory tends to hit a ball while bouncing it with the head at the time of impact. Hence, the use of a golf club having a shaft with a tight proximal side allows this user to easily have a swing, so a shaft with a stiff proximal end is suitable for him or her.
A user who tends to largely turn his or her hands at the time of impact prefers that the face surface should rotate to follow a turn of his or her hands, and therefore prefers moderate head behaviors. Hence, a shaft with a stiff distal end is suitable for this user. Conversely, for a user who tends to turn his or her hands little at the time of impact, the head preferably travels at the time of impact. Hence, a shaft with a soft distal end is suitable for this user.
Referring to
Region c corresponds to a relatively small vertical launch angle and a relatively large back spin amount. Hence, a shaft with both a soft proximal end and distal end is suitable for region c, so group III is associated with region c as recommended shafts. Region d corresponds to both a relatively small vertical launch angle and back spin amount. Hence, a shaft with a soft proximal end and a stiff distal end is suitable for region d, so group IV is associated with region d as recommended shafts.
In the process of step S15, the CPU 101 specifies one of regions a to d, to which the user belongs, from the measurement results of the vertical launch angle and back spin amount acquired in step S11. Next, the CPU 101 specifies a shaft group corresponding to the specified region among groups I to IV. Moreover, the CPU 101 specifies the flex of a shaft suitable for the user from the head speed acquired in step S11. The CPU 101 selects a shaft, which belongs to the specified group and flex, as a recommended shaft by referring to the shaft classification information shown in
Referring back to
In this manner, in this embodiment, since a recommended shaft is selected using two types of recommended shaft information which adopt different measurement parameters, a recommended shaft corresponding to the user level can be selected.
Although users are classified into four groups in accordance with the vertical launch angle and the back spin amount to generate the recommended shaft information shown in
Region e corresponds to, for example, a vertical launch angle of 12° (inclusive) to 16° (inclusive) and a back spin amount of 2,000 to 3,000 rpm for a driver, and preferably corresponds to an ideal range of the vertical launch angle of a struck ball and the back spin amount on this ball. In other words, users belonging to region e are advanced golfers.
When recommended shaft information is generated as shown in
A process associated with recommended shaft selection when users and recommended shafts are each classified into five groups, as in this embodiment, is the same as in step S15 of
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2009-293806, filed Dec. 25, 2009, which is hereby incorporated by reference herein in its entirety.
Number | Date | Country | Kind |
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2009-293806 | Dec 2009 | JP | national |