US20030119597A1 - Golf club - Google Patents

Abstract

A golf club permits a swing that does less harm to the body of a golfer and, in particular, to his vertebral column. The club has a shaft length that, in an embodiment of the invention, is longer than a standard shaft length by more than 2 inches, and a lie angle that more acute than a standard lie angle.

Description

BACKGROUND OF INVENTION
• Experiments with professional and amateur golfers have shown that pathological loading of the lumbar vertebral column occurs during the golf swing. This explains the back pains that occur with professional golfers with increasing frequency and that can force the golfer to change the swing or give up the sport.[0001]
• The cause, in particular, is the bent posture and the intense twisting of the lumbar vertebral column during the back swing and the follow-through. In the process, not only is the intervertebral disk region pathologically stressed, but the smaller vertebral joints are also pathologically loaded. The latter become prematurely worn.[0002]
• A younger golfer, with pronounced bending of the lumbar vertebral column and bending of the pelvis, can execute a powerful swing without pain. With increasing age, however, this ability is reduced.[0003]
• In addition, for the golfer, a uniform repetition of this swing, which rotates about two axes (perpendicular body axis and vertebral column axis inclined forward) is difficult to coordinate, since he has to control a complex sequence of movements during the execution of this swing.[0004]
SUMMARY OF INVENTION
• The object of the invention is to provide a golf club that permits a swing that does less harm to the body of a golfer and in particular to his vertebral column.[0005]
• The invention is based on the idea that a more upright swing, which rotates essentially about only one body axis, reduces the pronounced twisting of the lumbar vertebral column and, as a result, reduces damage to the vertebral column structures and the pain associated with it. According to the invention, for the more upright swing, and as compared conventional golf club proportions that are matched to the normally practiced golf swing (which is detrimental to health), this requires an increase in the club shaft length and a reduction in the lie angle. The lie angle is defined by a horizontal axis in the shot direction, and is the angle between the club shaft and the underside of the club head.[0006]
• Among golf clubs, the “irons” as well as the “woods” are standardized with regard to both the geometry of their club head and their grip shaft length. It is known that golfers, as a function of their height, then use golf clubs that deviate from this standard shaft length by a certain size. This is because it is evident that a tall golfer needs a longer shaft than a smaller golfer in order to execute the same swing. The known maximum for very tall golfers is 2″ (50.8 mm) more than the standard length, which for golf clubs in the iron category, to which the present invention relates, can be gathered from Table I.[0007]

  	TABLE I
  	Iron	Length (inches)	Length (cm)

  	1	39.75	100.965
  	2	39.25	99.695
  	3	38.75	98.425
  	4	38.25	97.115
  	5	37.75	95.885
  	6	37.25	94.615
  	7	36.75	93.345
  	8	36.25	92.075
  	9	35.75	90.805
  	PW	35.50	90.17
  	MW	35.25	89.535
  	SW	35.25	89.535
  	LW	35.00	88.90

• A shaft length that is 2″ longer than the standard length is not shown in the prior art because even the tallest golfer could no longer realize the swing technique which corresponds to the known and conventional school. However, as it is important in golf to hit the ball with maximum reproducibility in order to hit it precisely toward the aiming point, the club geometries for realizing the shot that can be reproduced according to rule have so far not deviated from the known described geometries.[0008]
• In contrast, however, for a golfer of average height, to whom the standard length according to Table I was previously allocated in order to execute the known conventional golf shot, a club having a shaft length that is longer than the standard shaft length by more than 2″ (5.08 cm), preferably by 3″-8″ (7.6-20.32 cm) and in particular preferably by 5″-6″ (12.70-15.24 cm), is provided according to the invention. The golf club thus constructed according to the invention is then held by the golfer at a flatter angle of inclination of his shaft in the neutral position at the start of the swing with the striking face of the club head at the ball. The golfer is then advantageously able to keep his upper body more upright and thus counteract the above-described detrimental effects of the conventional golf swing, bent forward to a greater degree.[0009]
• To adapt the club geometry, according to the invention, to the more upright golf swing, the lie angle is preferably more acute than the standard lie angle of conventional “irons” by more than 4°; the standard lie angle can be seen from Table II:[0010]

  	TABLE II
  	Iron	Lie (°)

  	1	58
  	2	58.50
  	3	59.50
  	4	60
  	5	61
  	6	61.50
  	7	62.5
  	8	63
  	9	64
  	PW	64.50
  	MW	64.50
  	SW	64.50
  	LW	64.50

• According to the invention, this results in the advantage that, with the upright upper body posture of the swing sequence assisted by the club according to the invention, the sole of the club head (its underside) can lie essentially parallel to the ground, while the club shaft, in the neutral position, assumes the flatter inclination described. Angles of between 2° and 20° below the standard size according to Table II and in particular between 8° and 20° below the standard size are preferred.[0011]
• The more upright swing assisted by the club according to the invention is to be carried out with the upper body bent only slightly forward (about 10° to about 20°). In this case, the essential measurement for adapting the club according to the invention to the body measurements of a golfer is preferably the distance of the base joints of the fingers to the ground. The larger club shaft length according to the invention, with the more upright posture of the upper body, then produces the centrifugal force during the swing. The club rotates, with this centrifugal force, about an axis inclined forward to a greater extent than is the conventional swing. In other words, it rotates in a swing plane tilted to a less pronounced extent from the horizontal than a conventional swing. At the same distance of the base joints of the fingers, the swing plane running through these base joints and, according to the invention, tilted to a less pronounced extent from the horizontal, results in the club being tangent to the ground at a greater radial distance from the finger base joints. This results in the longer club shaft length which is advantageous according to the invention.[0012]
• During the shot, the club head speed is in principle an important factor for the shot distance. Various factors then have to be matched to one another so that as fast a club head speed as possible can be achieved. These include factors depending on the individual, such as muscle power, height, arm and leg length and also the distance of the hands from the ground in the neutral position. There are also factors which depend on the club geometry, such as the club shaft length, the shaft flexibility and in particular also the weight of the club head. Normally the head of an iron golf club has a weight of 200 g to 220 g.[0013]
• The known clubs in the “1 iron” to “9 iron” category normally have a flat club head underside, which in the neutral position rests flat on the ground. In contrast, according to the invention, a convex curvature of the club head underside is used, the curvature defined relative to a horizontal axis perpendicular to the shot direction. As a result, in the event of a shot that is not quite precise, the risk of the club opening or closing, due to contact with the ground with either the leading edge or the trailing edge of the underside, can be advantageously reduced. According to the invention, a curved transition between the club head underside (sole) and the shaft can also be used.[0014]
• Furthermore, some trials with tour golfers have shown that it is advantageous if the hands of the golfer are located in front of the club head in the shot direction at the moment of impact. In order to ensure that the club head lies behind the hands at the moment of impact, the club head, according to the invention, can be displaced to the rear relative to the hosel (the extension of the club head at the bottom end of the shaft) in golf clubs in the “1 iron” to “9 iron” category.[0015]
• Alternatively, or additionally, it is particularly preferred according to the invention to slightly invert the striking face of the club head relative to the shaft, i.e., to realize an inversion angle (between the striking face and the shaft) that is less than 180°, which is normally realized in the prior art. This has several advantages. During the downswing and follow-through, on account of the dynamic forces, bending and torsion of the shaft occur and, therefore, opening of the club blade occurs. The inversion angle according to the invention of less than 180° counteracts this effect. However, this inversion angle according to the invention also causes the hand to be situated in front of the ball at the moment of impact.[0016]
BRIEF DESCRIPTION OF DRAWINGS
• The present invention is described below with reference to the attached drawings, wherein:[0017]
• FIG. 1 schematically shows a golf club according to the invention, viewed from the striking direction of the ball in the neutral position;[0018]
• FIG. 2 shows a golf club according to the invention in side view;[0019]
• FIG. 3 shows a golf club according to the invention in plan view.[0020]
DETAILED DESCRIPTION
• A[0021]golf club2 with aclub head4 and ashaft6 can be seen in FIG. 1. Thegolf club2 is depicted in the neutral position, i.e., thegolf head4 rests with its underside or sole8 on theground10. In this position, an angle12 (lie angle) is obtained between the sole8 of theclub head4 and theshaft6. According to the invention, thislie angle12 is smaller than in agolf club2′ according to the prior art, theshaft6′ of which, with the club head in the same position, is indicated by broken lines.
• A golfer having a certain height and, in particular, a certain individual distance A of his finger base joints from the[0022]ground10 must execute a swing about anaxis16′ with theclub2′ according to the prior art. Thisaxis16′ is inclined forward to a noticeably greater extent than theaxis16, about which a swing can be performed with theclub2 according to the invention. The golfer is not depicted, but the height of his finger base joints is indicated by thehorizontal line14. It should be noted that the axes and proportions shown only serve for viewing schematically. Thus, by comparing theswing axis16′ according to the prior art with theswing axis16 in accordance with the invention, it can be seen from FIG. 1 that theclub2 according to the invention, having a longer shaft length L, at the same distance A of the finger base joints from the ground, permits a more upright swing.
• In addition, it can be seen from[0023]line8ain FIG. 1 that the sole8, according to the invention, need not be flat, but may also be convexly curved about an axis in the shot direction. FIG. 2, in the side view of theclub head4 shown there, illustrates a convex curve according to the invention of the sole8aabout a horizontal axis perpendicular to the shot direction.
• It can also be seen in FIG. 2 that—in order to have the hands in front of the ball at the moment of impact—the[0024]striking face18 of theclub head4 is offset to the rear (to the left in FIG. 2) relative to thehosel20.
• With the same aim of getting the hands in front of the ball, an[0025]inversion angle22 of less than 180° between the leading edge of thestriking face18 of theclub2 and theshaft 6 can be seen in FIG. 3 in the plan view of theclub2.

Claims (7)

What is claimed is:

1. A golf club in the iron category, having a head with design parameters, including a lie angle, which are standardized as a function of the category number, and a shaft with a shaft length which has a standard shaft length assigned to it as a function of the category number, wherein the shaft length is longer than the standard shaft length by more than 2 inches (5.08 cm), and wherein the lie angle is more acute than the standard lie angle.

2. The golf club as claimed inclaim 1, wherein the lie angle is more acute than the standard lie angle by 2° to 10°.

3. The golf club as claimed in either of the preceding claims, wherein the lie angle is more acute than the standard lie angle by 5° to 8°.

4. The golf club as claimed in one of the preceding claims, wherein the shaft length is longer than the standard shaft length by 3″ to 8″.

5. The golf club as claimed in one of the preceding claims, wherein the shaft length is longer than the standard shaft length by 5″ to 6″.

6. The golf club as claimed in one of the preceding claims, wherein the inversion angle is less than 180°.

7. The golf club as claimed in one of the preceding claims, wherein the bottom edge of the club head is convexly curved about an axis inclined in the shot direction.

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