JP2006102023A - Golf club set - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a golf club set which makes the weight of any of the golf clubs feel almost constant by using the indicator different from the rotary moment so far used as the indicator for the weight of the golf club felt by the golfers during the swing. <P>SOLUTION: The golf club set 1 made up of ten golf clubs different in the loft. The normal vertical to the face plane passing through the position of the center of gravity of each golf club head is projected onto the plane vertical to the axis of the golf club shaft to regulate the projection line. Each of the golf clubs is orthogonal to the projection line and the axis of the golf club shaft separately while the inertial moment [I<SB>c</SB>+W×(X+1)<SP>2</SP>] is almost constant on the center axis or on the straight line as axis passing the extension line thereof. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a golf club set including a plurality of golf clubs having different loft angles.

Golf is a sport in which 14 golf clubs are used to fly a golf ball to a predetermined position, and a plurality of golf clubs having different loft angles are provided on the market as golf club sets.
Such a golf club set is designed so that the flight distance of the golf ball gradually increases or decreases by changing the loft angle and the golf club length. For example, in an iron golf club set, it is 150 yards for a 5 iron and 140 yards for a 6 iron. The 7-iron is designed with a flying distance adjusted to 130 yards. In other words, in the golf club set, the golf club is designed to harmonize with the flight distance.

However, the sense of weight of a golf club that a golfer actually feels immediately before hitting a golf ball may not be harmonized by the golf club, even if the golf club set has a harmonized flight distance. For example, it feels light with a 5 iron, feels heavy with a 6 iron, and feels light with a 7 iron. In such a case, when a 6 iron is used, the golfer tries to swing with a strong golf swing as compared with the 5 iron or 7 iron so as not to lose the weight of the golf club. For this reason, the golfer may develop a force due to excessive consciousness of the golf swing, and may not be able to hit the golf ball properly.
On the other hand, as an index of the weight of the golf club felt by the golfer during golf swing, the mass of the golf club is calculated by subtracting a constant (for example, 14 inches) from the distance between the center of gravity of the golf club and the grip end. Multiplicative rotational moments have been used. However, this rotational moment is not always a sufficient indicator of the weight of the golf club.

  Therefore, the present invention can feel the weight of a golf club substantially constant in any golf club using an index of the weight of a golf club felt by a golfer, which is different from the conventional rotational moment. An object is to provide a golf club set.

In order to achieve the above object, the present invention provides a golf club set composed of a plurality of golf clubs having different loft angles, and each of the plurality of golf clubs passes through the center of gravity position of the golf club head. When the projection line is defined by projecting a normal line perpendicular to the face surface onto a plane perpendicular to the central axis of the golf club shaft, the plurality of golf clubs are separated from the projection line and the center of the golf club shaft. Provided is a golf club set characterized in that a moment of inertia of a golf club having an axis that is orthogonal to each of the axes and that has a straight line passing through the central axis or an extension of the central axis as an axis is substantially constant.
That is, the plurality of moments of inertia of the golf club when the golf club rotates toward the hitting direction of the golf club about the direction orthogonal to the central axis of the golf club shaft immediately before hitting the golf ball during golf swing. The moment of inertia is substantially constant.
The fact that the moment of inertia of a golf club is substantially constant means that the moment of inertia of any golf club is included in a range within ± 4% of the average value of the moments of inertia of a plurality of golf clubs.

The moment of inertia of the golf club is the moment of inertia when the golf club rotates in the direction of hitting the golf club around the direction perpendicular to the central axis of the golf club shaft just before hitting the golf ball during golf swing. The rotation of the golf club is a rotational movement about a position away from a grip end of the golf club on the extension line of the central axis of the golf club shaft, and the moment of inertia of each golf club is The moment of inertia around the center of rotation is preferable. At this time, the distance from the grip end to the rotation center is set in advance, and the golf club set is configured so that the moment of inertia of the golf club becomes substantially constant using the divided distance. It is preferable.
The loft angle is preferably in the range of 15 to 45 degrees.

  In the golf club set of the present invention, the moment of inertia of the above-described golf club is substantially constant in the plurality of golf clubs. For this reason, the inertia term in the rotational motion of the golf club can be made constant immediately before the impact of the golf ball during golf swing. Thereby, the golfer can feel the weight of the golf club at the time of golf swing substantially constant without depending on the count, and can perform a stable golf swing without depending on the count.

  Hereinafter, the golf club set of the present invention will be described in detail based on a preferred embodiment shown in the accompanying drawings.

FIG. 1 is a diagram illustrating an example of a golf club set, and FIG. 2 is a diagram illustrating an example of one golf club in the golf club set.
The golf club set 1 includes irons (A3 to AS) 10 for each number of irons (A3) to 9 (A9) to pitching wedges (AP), approach wedges (AA), and sand wedges (AS). Consists of books. Each iron has a grip 16 at one end of the golf club shaft 14 and a golf club head 12 at the other end. The golf club head 12 is connected to the golf club shaft 14 via a socket on a hosel protruding upward on the heel side.

  Here, the count is a loft represented by numbers (natural numbers), letters, symbols or the like given to each golf club so that golf clubs having different loft angles can be arranged in the order of the loft angles. It is the content of the identification information regarding the order of the angles, and the loft angle of each count is appropriately set by those skilled in the art at constant or substantially constant intervals. Also, a large count means a count with a large loft angle.

The loft angles θ of these irons A3 to AS are, for example, 21 ° for A3, 24 ° for A4, 27 ° for A5, 30 ° for A6, 34 ° for A7, 38 ° for A8, 42 ° for A9, AP Is 47 °, AA is 52 °, AS is 57 °, and the loft angle θ is increased. The counts having a loft angle θ of 16 ° to 41 ° are six counts A3 to A8. In addition, the loft angles of the irons A3 to AS increase with a step size of 3 ° from A3 to A6, increase with a step size of 4 ° from A7 to A9, and with a step size of 5 ° from AP to AS. The step size of the loft angle of the irons A3 to AS is not limited to this, but may be a constant step size such as 3 ° or 4 °.
In addition, the length of the golf club shaft from the end of the grip 16 to the lower end of the golf club head 12 is gradually shortened as the count is increased. In other words, the golf club shaft 14 having a smaller count has a longer length and a smaller loft angle.

In this embodiment, ten irons are used as the golf club set 1. However, the golf club set of the present invention includes not only an iron golf club set but also a wood golf club set, a wood golf club set, and an iron. A golf club set in which the boundaries of the golf club set are removed, a golf club set corresponding only to a long iron, or a so-called golf club set that is intermediate in performance between a wood golf club and an iron golf club, and so-called hard to classify A golf club set including a utility golf club includes a golf club set including a plurality of golf clubs having different loft angles θ.
In addition, in the golf club set 1, all the golf clubs in which the loft angle in the golf club set 1 is within the range of 15 to 45 degrees are within the range of the golf club set of the present invention, that is, as described later. In addition, it is preferable that the moment of inertia of the golf club when the golf club rotates toward the hitting direction of the golf club is substantially constant.

A golf club 10 shown in FIG. 2 is an iron-based golf club having a golf club head 12, a golf club shaft 14, and a grip 16.
In FIG. 2, the center of gravity G of the golf club 10 is a point on the center axis CL of the golf club shaft 10 at a distance l (this distance is referred to as a center of gravity position l) from the upper end of the grip end.
As shown in FIG. 2, the golf club 10 is placed on a horizontal plane P, an inclined surface Q inclined at an angle of 60 degrees with respect to the horizontal plane P is applied to the sole surface of the golf club head 12, and the golf club shaft 10 extends. When the intersection 18 between the horizontal plane and the inclined plane is determined, the length L of the golf club is the distance from the intersection 18 to the grip end point 19. The length L of the golf club is measured by the measurement method stipulated in the Rules II.1.c of “Golf Rules 2004 Edition” published by the Japan Golf Association.

FIG. 3 is a diagram schematically illustrating the behavior of the golf club 10 when the golfer performs a golf swing while holding the golf club 10.
Just before the golf club 10 hits the golf ball 20, the golf club head 12 performs a circular motion with the point O as the center of rotation, and the golf club shaft 14 is a straight line connecting the golf ball 20 and the point O (the center point of the circular motion). Approximate matches above. That is, immediately before hitting a golf ball during golf swing, the golf club performs a rotational motion around the point O toward the hitting direction of the golf club (D direction in FIG. 3). This point O is at a unique position corresponding to the golfer's golf swing.

In the golf club set of the present invention, the golf club is hit with the moment of inertia in the rotational motion around the point O of the golf club, that is, the direction orthogonal to the central axis of the golf club shaft immediately before hitting the golf ball during golf swing. The moment of inertia of the golf club when the golf club rotates in the direction is substantially constant.
That is, a projection line defined by projecting a normal line that passes through the center of gravity of the golf club head and is perpendicular to the face surface onto a plane perpendicular to the central axis of the golf club shaft, and the central axis of the golf club shaft. The moment of inertia of the golf club is approximately constant with the center axis or a straight line passing through the extension line of the center axis orthogonal to each other.
FIG. 4 is a view for explaining a straight line that defines the axis of the moment of inertia, and is a view of the golf club as viewed from the toe side and slightly rearward. A normal line P passing through the center of gravity G ₀ of the golf club head and perpendicular to the face surface of the golf club head is defined, and the normal line P is projected onto a plane Q perpendicular to the central axis CL of the golf club shaft. A line R is defined. At this time, the axis of moment of inertia in the present invention is an axis that is orthogonal to the projection line R and the central axis CL of the golf club shaft and passes through the central axis CL or an extension of the central axis CL. In FIG. 4, straight lines S orthogonal to the projection line R and the center axis CL of the golf club shaft are shown, and the axis of inertia moment of the present invention is an axis parallel to the straight line S. Note that a plane Q perpendicular to the central axis CL shown in FIG. 4 is a plane inclined downward in the depth direction of the paper of FIG. 4 due to the lie angle of the golf club. Therefore, the straight line S faces downward in the depth direction in FIG.

As shown in FIG. 3, such a golf club performs a rotational motion immediately before hitting the golf ball 20 of the golf club head 12. The moment of inertia in this rotational motion can be expressed as [I _c + W · (X + l) ² ]. Here, I _c is the moment of inertia around the center of gravity G of the golf club, W is the total mass of the golf club, l is the distance from the grip end of the golf club to the center of gravity G of the golf club, and a constant X is the distance between the grip end and the point O.
In the golf club set of the present invention, golfers to be used are classified according to a constant X of the moment of inertia [I _c + W · (X + 1) ² ].

The reason why the golfers to be used are classified according to the constant X is that the constant X is not a design parameter that can be changed for the golf club, but is a value specific to the golf swing of the golfer. When the golfer knows the value of the constant X specific to his golf swing, a golf club set can be found that makes the moment of inertia [I _c + W · (X + 1) ² ] of the golf club substantially constant.
That is, the golf club set has a configuration in which an identification display body that displays information for classifying golf clubs based on a constant X is attached to the golf club head to define a golfer to be used.

On the other hand, in such a golf club set, the moment of inertia [I _c + W · (X + 1) ² ] of each golf club is made substantially constant as an index of the weight of the golf club that the golfer feels during golf swing. This is to make the weight of the golf club felt by the golfer almost constant regardless of the count of the golf club set. In other words, the moment of inertia acts as a parameter that defines the inertial term of the rotational motion representing the weight during the rotational motion of the golf club performed immediately before hitting the golf ball. Thus, the golfer can feel the weight of the golf club substantially constant and perform a stable golf swing regardless of the golf club count (golf club length and weight).

In such a golf club set, the moment of inertia [I _c + W · (X + 1) ² ] can be used as a parameter defining the inertial term of the rotational motion immediately before hitting the golf ball, as shown below. In addition, the present inventors have found that the rotational energy amount of a golf club immediately before hitting a golf ball can be determined to be unique to the golfer together with the constant X.
Immediately before the golf ball is hit, the rotational energy amount E of the golf club can be expressed by the following formula (1) using the above I _c , W, l, X, and L.
1/2 · [I _c + W · (X + 1) ² ] · [HS / (X + L)] ² = E (1)
Here, if the rotational energy amount E is assumed to be an amount inherent to the golf swing together with the constant X, and the values of I _c , W, l, and L are changed in this state, the calculation is predicted from the above formula (1). The predicted calculation result of the head speed HS is extremely highly correlated with the measurement result of the head speed when the golf club in which I _c , W, l, and L are changed is actually golf swinged. FIG. 5 is a graph showing a comparison between the head speed prediction calculation result and the measurement result, and shows how the head speed changes depending on the mass (total mass W) of the golf club. According to FIG. 5, the prediction calculation result and the measurement result have an extremely high correlation coefficient R ² of 0.990. In addition, in FIG. 5, even in golfers G _a and G _{b having} different golf swings, the correlation between the predicted calculation results and the measurement results is extremely high.

Thus, the rotational energy amount E immediately before hitting the golf ball can be determined to be unique to the golf swing of the golfer together with the constant X. Therefore, the golfer's inherent rotational energy amount E immediately before hitting the golf ball can be expressed by equation (1), and the inertial moment [I _c + W · (X + l) of the golf club that defines the inertial term of the rotational motion of the golf club. ² ] can be used as an index of the weight of the golf club felt by a golfer inherently having a certain amount of rotational energy.
In the golf club set, I _c , W, and l vary according to the golf club number, but the inertia moment [I _c + W · (X + l) ² ] is substantially constant with respect to the set constant X. It is comprised so that.

In order for a golfer to find a golf club set in which the above-mentioned moment of inertia of the golf club becomes substantially uniform from among a plurality of golf club sets, the constant X needs to be known. The golfer can know the constant X by the following method.
First, golf swing is performed using the golf club A and the golf club B having different golf club specifications depending on the golfer. The golf club A has a golf club moment of inertia I _ca , a golf club length L _a , and a total mass W _a of the golf club when the golf club rotates in the direction of hitting the golf club. The value of the center of gravity point position l _a of the golf club is known. Here, the inertia moment I _ca is the inertia around the center of gravity G about the direction orthogonal to the direction of the axis S of the golf club shaft (see FIG. 3) and the direction of striking the golf club (D direction; see FIG. 3). It is a moment. Meanwhile Golf Club B are also known center of gravity G of inertia around the moment I _cb golf club _10, golf club length L _b, the value of the total mass W _b and the golf club center of gravity position l _b of the golf club . Golf clubs A and B have different golf club specifications, and any one or more of the moment of inertia around the center of gravity, the length of the golf club, the total mass of the golf club, and the position of the center of gravity of the golf club are different. Yes.
The head speeds HS _a and HS _b immediately before hitting the golf balls in the golf clubs A and B are measured using a known head speed measuring device and acquired by a computer.

  Next, from the values of the moments of inertia of the golf clubs A and B, the length of the golf club, the total mass of the golf club, the position of the center of gravity of the golf club, and the head speed, the constant X is calculated using the equation (2). Calculated. Here, the amount of rotational energy is a value unique to the golf swing of the golfer, and it is utilized that it is constant regardless of the golf clubs A and B having different specifications.

½ · [I _ca + W _a · (X + l _a ) ² ] · [HS _a / (X + L _a )] ²
= 1/2 · [I _cb + W _b · (X + l _b ) ² ] · [HS _b / (X + L _b )] ² (2)

Thus, the calculated constant X is known to the golfer, and the moment of inertia [I _c + W · (X + 1) ² ] is based on the count while referring to the identification display attached to the golf club head 12. A golf club set that is substantially uniform can be found from a large number of golf club sets.
In the above example, the constant X and the rotational energy amount E are calculated using the two golf clubs A and B. However, in the present invention, the calculation can be performed using at least two golf clubs having different specifications. . For example, when the rotational energy amount E is calculated using three golf clubs, the constant X may be obtained and set so that the deviation of the rotational energy amounts of the three golf clubs is minimized.

Note that the value of the constant X is an inherent constant characterizing the golf swing determined by the golfer. On the other hand, in the golf club set of the present invention, the moment of inertia [I _c + W · (X + 1) ² ] is substantially constant with respect to the constant X. It is configured. Here, “substantially constant” means that the moments of inertia of the golf clubs of each number are included within a range of ± 4% with respect to the average value of these moments of inertia. In the present invention, the constant X may be fixed using a predetermined value, for example, an average value, as long as it is substantially constant. For example, the constant X may be a value common to all golfers, X = 0.

The head speed in the present invention is measured using a head speed measuring device 30 as shown in FIG. The head speed measuring device 30 is a known measuring device, and includes a beam emitting unit 22, a light receiving unit 24, and a measuring unit 26.
The measuring unit 26 calculates a head speed by measuring a deviation in timing at which the light receiving unit 24 stops receiving the light beam when the golf club head crosses each of the two light beams. The head speed measuring device 30 is disposed at the head trajectory position immediately before impact in order to measure the head speed immediately before impact, and is 100 mm backward from the center of the golf ball starting from 40 mm backward in the flying direction. It is desirable that a light beam is arranged in each of the sections.

  The golf club set of the present invention has been described in detail above. However, the present invention is not limited to the above embodiment, and various modifications and changes may be made without departing from the spirit of the present invention. is there.

It is a figure which shows an example of the golf club set of this invention. It is a figure explaining the iron system golf club of the golf club set in this invention. It is a figure explaining the behavior of a golf club when a golfer holds a golf club and performs a golf swing. It is a figure explaining the straight line which prescribes | regulates the axis | shaft of the moment of inertia in this invention. It is a figure which shows the relationship between the mass of a golf club, and head speed. It is a figure explaining the head speed measuring device of a golf club.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Golf club set 10 Golf club 12 Golf club head 14 Golf club shaft 16 Grip 18 Intersection 19 End point 20 Golf ball 22 Beam injection unit 24 Light reception unit 26 Measurement unit 26
30 Head speed measuring device

Claims (3)

A golf club set composed of a plurality of golf clubs having different loft angles,
In each of the plurality of golf clubs, when a projection line is defined by projecting a normal line that passes through the center of gravity of the golf club head and is perpendicular to the face surface to a surface that is perpendicular to the central axis of the golf club shaft, The plurality of golf clubs has a moment of inertia of the golf club about a straight line that is orthogonal to the projection line and the central axis of the golf club shaft and passes through the central axis or an extension line of the central axis. A golf club set characterized by being substantially constant. The moment of inertia of the golf club is the moment of inertia when the golf club rotates in the direction of hitting the golf club around the direction orthogonal to the central axis of the golf club shaft immediately before hitting the golf ball during golf swing,
The rotation of the golf club is a rotational movement about a position that is a predetermined distance from the grip end of the golf club on the extension line of the central axis of the golf club shaft,
The golf club set according to claim 1, wherein the moment of inertia of each golf club is a moment of inertia around the center of rotation.   The golf club set according to claim 2, wherein a distance from the grip end to the rotation center is set in advance, and the inertia moment of the golf club is configured to be substantially constant using the divided distance.

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