Wedge type golf club including pitching wedge, approach wedge and sand wedge

1. Field of the Invention

The present invention relates to a golf club, including a pitching wedge, an approach wedge and a sand wedge.

2. Description of the Related Art

Golf clubs are classified roughly into a wood type, an iron type and a putter type. The wood-type golf club is used to give an initially low shot and hit a long ball, while the iron-type golf club is used to give an initially high shot to hit the ball with a backspin, taking aim at a target position from above, and the putter is used on a green.

Among the iron-type golf clubs, a pitching wedge type is used to hit a shot for giving a carry of up to about 110 yards (101 m), while a sand wedge type designed mainly for playing on a banker is used to hit a shot for giving a carry of up to nearly 80 yards (73 m).

In these wedge types, a tilt angle of a face surface (a golf ball hitting area), i.e., a loft angle is set at approximately 52 to 56 degrees and a tilt angle of a shaft, i.e., a lie angle is set at nearly 64 degrees.

In each of these iron-type golf club heads, there are provided a sole face acting as a ground contact surface in a lower portion thereof and a face surface acting as a golf ball hitting area in front thereof. The face surface is formed with score lines and further the head is formed with a toe, a heel and a hosel for fitting a shaft thereto, and a depressed portion at a rear, as disclosed in Japanese unexamined patent publication No. 7-255879 along with its FIG. 1, FIG. 7.

For an approach shot when the golf ball is shot to be carried on the green, a pitch-and-run shot and a pitch shot are used. These shots are golf ball hitting methods for hitting the golf ball with a larger magnitude of the backspin (a reverse spin) to give a comparatively high shot, thus stopping the golf ball on the green. Particularly, the pitch shot method aims at giving the golf ball a strong backspin, so that the golf ball is dropped short of a cup on the green and then immediately stopped.

Heretofore, the face surface is formed with multiple small grooves called score lines as a means for applying a backspin to a golf ball at the time of hitting it. The assignee of the present application has ever filed applications (e.g., Japanese unexamined patent publication No. 2003-199851) pertaining to a golf club head, in which the score lines capable of applying a strong backspin to a ball are provided on the face surface by forming score lines on the face surface by press working, and then flattening the face surface by machining or press working to thereby sharpen the edge angles of the score lines so as to make the golf ball easy to be caught in the score lines, so that an effective spin can be applied to the golf ball.

Restrictions are, however, imposed on the face surface and the score lines by the Golf Rules due to their large influences on spin imparting performance. Therefore, there has not only been a limitation in the improvement of the edge portions of the score lines but also there have been possibilities that the golf ball may be cut by such sharp edge portions of the prior art at the time of striking the same.

Whilst in the case that the angles of the edge portion of the score lines are formed sharp in accordance with the prior art, the golf ball becomes easy to be caught in the edge portions so that a backspin will be easily applied thereto, there remains, however, such a problem that not only the sharpness of each score line edge is decreased slightly at every shot but sands or the like will get into the score lines especially in the case of a bunker shot to make it impossible to ensure the sharpness of the edge portions.

To eliminate the above problems, it is therefore, an object of the invention to provide a golf club having a head with a face surface formed with score lines and a shaft connected with the head, which enables a strong backspin to be applied without the aid of the face surface having the score lines.

An aspect of the present invention is a wedge-type golf club, including a pitching wedge, an approach wedge and a sand wedge, comprising: a head having a sole face provided in a lower portion that acts as a ground contact surface, a face surface acting as a ball striking surface, provided on a front of said head with a certain loft angle, a shaft connecting portion on one side thereof, multiple score lines formed on the face surface of said head, and a shaft connected to said shaft connecting portion,

wherein a height of the center of gravity of said head is at least 21.335 mm and greater than a radius of a golf ball, the height of the center of gravity of said head being defined as a distance from a horizontal plane flush with the sole face of said head to the center of gravity of said head;

the center of gravity of said head is provided at an anterior position to said face surface, and

wherein for the score lines as measured, 50% or more of the measured values of X divided by the pitch of the score line are less than or equal to 0.0030″ (0.0762 mm²/mm), where X denotes a traverse cross section of a groove per one score line, and the pitch of the score line is defined by the sum of the groove width and the groove separation.

Thus, the center of gravity of the head is positioned in a higher position than the center of a golf ball at the time of hitting a shot, and thus the face surface is allowed to rotate downward or clockwise due to the ball impact thus imparted, so that so-called gear effect is generated to thereby be able to accelerate the backspin of the ball even if the face is the one in which the backspin is hard to accelerate.

Further, as the above structure is employed for wedge type golf club, an approach shot from around a green can be preformed correctly.

Also, it is possible to ensure a height distance greater than a radius of a golf ball regulated under the current golfing rules.

Still also, as the center of gravity is arranged in a position anterior to the face surface, a ball striking angle at the time of hitting a golf ball can be decreased.

Another aspect of the present invention is a wedge-type golf club as set forth in the foregoing aspect, wherein an upper protrusion and a lower protrusion are provided spacedly rearwardly of upper and lower positions of said head, respectively such that a distance between a rear end of said upper protrusion and said face surface is greater than a distance between a rear end of said lower protrusion and said face surface.