US20070032311A1

US20070032311A1 - Golf club head and golf club

Info

Publication number: US20070032311A1
Application number: US11/313,920
Authority: US
Inventors: Ryota Kajita
Original assignee: Bridgestone Sports Co Ltd
Current assignee: Bridgestone Sports Co Ltd
Priority date: 2005-08-04
Filing date: 2005-12-22
Publication date: 2007-02-08
Also published as: JP2007037834A

Abstract

In a golf club head having a shape of a Mallet-type patter, a width of a sole face is in a range of 30 mm to 80 mm. A loft angle of the golf club head is in a range of 10° to 40°. A thickness A of a top blade satisfies a relationship:
10 mm≦A≦SW−5 mm. A weight of the golf club head is in a range of 350 g to 450 g.

Description

This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2005-226862 filed on Aug. 4, 2005, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention
The invention relates to an approach golf club, which is used for hitting a ball toward a pin from the periphery of the green and can be swung like a putting stroke, and its head.
2. Description of the Related Art
Golf clubs called “jigger” or “chipper” are known as golf clubs for ordinary amateur golfers that are dedicated to approach shots. For example, a golf club is known whose head stands halfway between an iron club and a putter in overall shape. More specifically, its hitting face has a loft angle of about 30° to 42° and the front portion of a sole face is continuous with the bottom portion of the hitting face to form a leading edge. In approach golf clubs of this type, the width of the sole face (in the direction from the leading edge of the hitting face to the rear side) is small (in general, smaller than 30 mm). As a result, even with golf clubs of this type, ordinary amateur golfers cannot greatly reduce the frequency of such bad shots as duffing (hitting the ground before the ball) and topping (hitting the ball above its equator).
To make approach shots easier, JP 2003-52874 A discloses approach golf clubs that particularly make duffing less likely to occur because their sole faces are as wide as 40 mm to 80 mm (see page 2 and FIG. 2 of JP 2003-52874 A). More specifically, they have wood-type heads in which the loft angle is 20° to 60°, the sole face width is 40 mm to 80 mm, and the front-rear width of the top portion is 30 mm to 75 mm. These golf clubs formed by attaching such a head to a shaft via a neck portion have overall lengths of 34 inches to 36 inches and lie angles of 65° to 75°.

SUMMARY OF THE INVENTION

The above-described wood-type approach golf clubs can decrease the probability of duffing because the wide sole fare provides high stability and a sense of security when address is taken and allows the head to slide on the grass smoothly. However, because of their shape, these golf clubs do not allow a player to swing with the same feeling as he or she strokes with a putter. Further, because of a hollow wood-type shape, the center of gravity of the head is deep and cannot be made as low as patter heads (additional reason: presence of the neck portion). These factors make it difficult Lo hit the ball at the sweet spot and obtain a stable distance. Since 2 to 3 yards are serious error in approach shot, amateur golfers unavoidably hit the ball by their own will and hence have difficulty obtaining a subtle sense of distance that is necessary for accurate approach shots.
The invention provides a golf club head and a golf club, which decrease the probability of duffing by enabling a putting-like stroke, lower the center of gravity, increase the stability in both direction and distance so that the direction and distance fall within prescribed ranges for shots made by a wide area of the hitting face and make approach shots easier.
According to one embodiment of the invention, in a golf club head having a shape of a Mallet-type patter, a width of a sole face is in a range of 30 mm to 80 mm. A loft angle of the golf club head is in a range of 10° to 40°. A thickness A of a top blade satisfies a relationship:
10 mm≦A≦SW−5 mm.
A weight of the golf club head is in a range of 350 g to 450 g.
According to one embodiment of the invention, a golf club includes a golf club head set froth above, a shaft and a neck portion. The shaft is inserted into the golf club head directly or through a hozel. The neck portion is formed with the top blade. The neck portion has a neck length equal to or less than 5 mm. An overall length of the golf club is in a range of 33 inches to 36 inches.
According to the structures set forth above, the wide sole face provides high stability and a sense of ease when address is taken. The golf club head can not only decrease the probability of duffing, but also make the center of gravity deeper and lower because the overall shape is like a mallet patter head rather than a hollow wood-type head. Since a player is caused to make a putting-like stroke rather than a swing to be made with golf clubs other than the putter, the player can easily hit the ball at the sweet spot. Even in the case of off-spot shots, sufficient directional stability is attained by virtue of toe-heel balance, As a result, a carry and a run that are determined by the loft angle and fall within prescribed ranges are expected. The golf club set forth above in which the shaft is attached to the top blade of the head allows a player to make a putting-like stroke easily and hence to easily adjust the distance in a delicate manner. In addition, setting the head weight at 350 to 450 g allows a player to make a slow stroke and thereby obtain a subtle sense of distance, which prevents hands-adjusted bad shots as would be played with golf clubs having a lightweight, hollow wood-type head.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a golf club head according to an embodiment of the present invention.
FIG. 2 is a front view of the head.
FIG. 3 is a side of the head.
FIG. 4 shows an over-hosel-type shaft attaching method.
FIG. 5 shows a golf club head according to another embodiment of the invention.
FIG. 6 is a perspective view, as viewed from the sole face side, of the head of FIG. 5.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Embodiments of the invention will be hereinafter described with reference to the drawings.
As shown in FIG. 1, a golf club head includes a hitting face 1, a top blade 2, a back face 3, a semicircular plate-like portion 4, which extends rearward from the back face 3, thick portions 5, which are disposed on the plate-like portion 4 on the toe side and the heel side thereof, and a neck portion 6 and a hosel 6A, which are provided on the top blade 2 for insertion and attachment of a shaft 10. The thickness of the top blade 2 (in the front-rear direction) is in a range of 10 mm to 25 mm. The bottom surface of the plate-like portion 4 forms a sole face of the golf club head. The contour of the sole face (plate-like portion 4) has the semi-circular shape as described above, and has a curvature radius of 300 mm or more. The height of the thick portions 5 is approximately a half of that of the top blade 2 to lower the center of gravity. The two thick portions 5 keep toe-heel balance. The loft angle α (see FIG. 3) of the hitting face 1 is in a range of 10° to 40°. The loft angle α being smaller than 10° is a loft angle of a patter. On the other hand, a conventional Mallet-type putter head has 30 mm to 80 mm in a width of a sole face, 3 degrees to 4 degrees in a loft angle and 350 g to 450 g in a head weight.
Referring to FIG. 2, an interval I between a center axis X of the shaft 10 and a heel h is equal to less than 0.625 inch. Even if a ball is hit at a position, which is out of the sweet spot in the hitting face 1 but between the sweet spot and the axis X, a resulting directional error is small. In the case of a center-shaft structure, a ball hit at a position deviated from the sweet spot to the toe t side is launched somewhat rightward at a high probability; and a ball, which is hit at a position deviated from the sweet spot to the heel h side is launched somewhat leftward at a high probability (in the case of a right-handed player). In contrast, where the shaft is attached to the head in the same manner as in the golf club of this embodiment, the directional error occurring in the case of an off-spot shot is small. In patters, what is called a center-shaft structure and a bent-shaft structure in which the shaft is bent have been known. In the approach golf club of this embodiment, the shaft 10 is directly attached to the top blade 2 at a position close to the heel h and lie angle of the club is large. The preferable lie angle range is in a range of 65° to 75°. The overall length of the club is in a range of 33 inches to 36 inches to enable a patting-like stroke. In FIG. 2, reference numeral 7 denotes a sole face. A sole height H at a position S, which is distant from the heel h by 10% of a head length L, is in a range of 0 mm to 5 mm. In this example, a sole height H at a position S, which is distant from the toe t by 10% of the head length L, is equal to the sole height H on the heel h side. However, the sole height H on the toe t side may be different from that on the heel h side, A neck length HL is equal to less than 5 mm. Since the sole height H at the position S, which is distant from the heel h by 10% of the head length L, is equal to or less than 5 mm, the sole position is low, as a result of which a risk of the heel h's hitting the ground before the ball is implanted in a golfer's mind and hence the golfer tends to move the sole face 7 parallel to the ground (patting-like stroke). This decreases the probability of duffing and topping and thereby makes the direction of the hitting face 1 less likely to deviate. The top blade 2 is approximately horizontal and an inclination BA up to about 10° is allowable. If the inclination BA is larger than 10°, it is difficult for a golfer to keep a sense of a putting-like stroke (moving the sole face 7 parallel to the ground).

FIG. 3 shows a width SW of the sole face 7, which is in a range of 30 mm to 80 mm. The reason why the loft angle α is in a range of 10° to 40° is described above. The weight of this golf club head is in a range of 350 g to 450 g. If the weight is lighter than 350 g, it is difficult for a player to make a putting-like stroke. If the weight is heavier than 450 g, a player tends to adjust the distance at an impact because the player feels that the head is too heavy.

	TABLE 1


	Example

	1	2	3	4	5

Loft angle	10°	15°	20°	30°	40°
Club length	34 in.	″	″	″	″
Head weight	350 g	″	″	″	″
Sole width SW	50 mm	″	″	″	″
Head material	Soft iron	″	″	″	″

Each of the golf clubs of Examples 1-5 was a Mallet-type club having the shape of FIG. 1, had 18 mm in the thickness of the top blade and had 350 mm in the curvature radius of the sole face (plate-like portion). Each of the golf clubs of Examples 1-5 was used by five evaluators for hitting balls actually on artificial turf. All the evaluators made a putting-like stroke, which is considered due to the length of 34 inches, which is the same as the length of patters, and an impression they would have that the sole was wide. Further, the evaluators played pitch-and-run shots using each golf club. All the five evaluators concluded that all the golf clubs were usable, that is, each of the examples would have a use for certain situations of a green and a region around the green. However, some evaluators concluded that the golf club with the loft angle of 40° had a sharp edge and hence might have cause topping and duffing in long approach shots.
The above-mentioned term “Mallet type” means a head that projects rearward and has a great center-of-gravity depth accordingly. The deep and low center of gravity increases the sweet area and hence allows a player to attain a prescribed distance by a smooth swing even if he/she does not hit the ball right at the sweet spot. Further, the deep center of gravity automatically helps the head to make a pendulum-like movement and hence allows a player to do a follow-through easily, resulting in high directional stability.
FIG. 4 shows another example of an attachment unit for attaching the shaft 10 to the head. This is what is called an over-hosel type in which a hosel 6A of a neck portion 6 is inserted into the shaft 10. The neck length HL is 5 mm or less. It is also possible to insert the shaft 10 directly into the top blade 2 without using the hosel 6A.
FIGS. 5 and 6 show still another embodiment in which opening holes 8 for a weight adjustment are defined in the back face 3 and the thick portions. Depending on an intended weight, the holes 8 may be left as they are or fitted with weights (not shown). Further, the sole face 7 is formed with two recessed side portions 7A to reduce the resistance of the grass in the case of rough shots.

Claims

1. A golf club head having a shape of a Mallet-type patter, wherein:

a width of a sole face is in a range of 30 mm to 80 mm,

a loft angle of the golf club head is in a range of 10° to 40°,

a thickness A of a top blade satisfies a relationship:

10 mm≦A≦SW−5 mm,

and

a weight of the golf club head is in a range of 350 g to 450 g.

2. The golf club head according to claim 1, wherein:

the sole face extends approximately horizontally, and

a surface of the top blade is approximately parallel to the sole face.

3. The golf club head according to claim 1, wherein a curvature radius of a contour of the sole face from a toe-side end to a heel-side end is greater than 300 mm.

4. The golf club head according claim 1, wherein a height of the sole face at a position, which is distant from a heel by 10% of a length of the golf club head is in a range of 0 mm to 5 mm.

5. The golf club head according to claim 1, comprising:

a hitting face having the loft angle of 10° to 40°;

a back face, which is opposite to the hitting face, being substantially perpendicular to a horizontal surface and substantially parallel to a shaft axis;

a plate portion that extends rearward from a lower end of the back face, the plate portion having a substantially semi-circular shape, the plate portion forming a part of the sole face; and

thick portions disposed on the plate portion on a heel side and a toe side.

6. A golf club comprising:

a golf club head of claim 1;

a shaft that is inserted into the golf club head directly or through a hozel; and

a neck portion formed with the top blade, the neck portion having a neck length equal to or less than 5 mm, wherein:

an overall length of the golf club is in a range of 33 inches to 36 inches.

7. The golf club according to claim 6, wherein an interval between an axis of the shaft and a heel of a hitting face is equal to or less than 0.625 inch.