EP0294107A2

EP0294107A2 - Golf club

Info

Publication number: EP0294107A2
Application number: EP88304794A
Authority: EP
Inventors: Kazumi Masaki
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-05-30
Filing date: 1988-05-26
Publication date: 1988-12-07
Also published as: KR880013591A; JPS63193065U; EP0294107A3; BR8802150A

Abstract

Disclosed is a novel balanced golf club wherein the center of gravity in a direction transverse to the club shaft (1) is located substantially on the club shaft by providing an eccentric weight (4) at a larger end of the club shaft (1) to cancel a weight eccentricity in the direction.

Description

The present invention relates to a golf club, specifically, to a golf club wherein the center of gravity in a direction transverse to the club shaft is located substantially on the club shaft.
As disclosed in Japanese Utility Model Laid-Open Nos.30,166/71 and 4,014/79, conventionally, an appropriate weight is attached equally around the club shaft of a golf club to dynamically balance it.
Such method, however, has the drawback that although the center of gravity in a direction along a club shaft can be finely controlled to meet the player, that in a direction transverse to the club shaft can not be controlled.
More particularly, since golf clubs are usually shaped into an elongated cylindrical rod, their center of gravity in a direction along a club shaft can be easily controlled, while that in a direction transverse to the club shaft can not be controlled with an ease because the club head is eccentrically held with respect to the club shaft.
Common drawbacks found in using such golf club are that, when swung up, its head weight tends to effect a rotation about the club shaft which may slip a grip point and an effort to avoid this may result in an unsatisfactory swinging characteristic, as well as that, when swung down, the head weight hinders a desirable orientation of the club shaft and also the attainment of a long straightforward ball.
With the viewpoint that the balance in a direction transverse to a club shaft is important in obtaining a desired swing action, the present inventor studied various means that can overcome these drawbacks of conventional golf club.
As a result, the present inventor found that the object is attainable with a golf club arranged in such manner that the center of gravity in a direction transverse to the club shaft is located substantially on the club shaft.
More particularly, the present invention relates to a golf club, characterized in that the center of gravity in a direction transverse to the club shaft is located substantially on the club shaft.
The present invention will hereinafter be explained with reference to the accompanying drawings in which:

FIG.1 is the side elevation view of a standard-type golf club;
FIG.2 is the longitudinal sectional view of the principal part of an embodiment according to the invention, wherein an eccentric weight in cork shape is tightly inserted in a larger end of a club shaft;
FIG.3 is the longitudinal sectional view of the principal part of another embodiment according to the invention, wherein an eccentric weight is covered with a grip while allowing the eccentric weight to contact with a larger end of a club shaft;
FIG.4 is the longitudinal sectional view of the principal part of still another embodiment according to the invention, wherein an attaching member bearing inside an eccentric weight is equipped to a club shaft;
FIG.5 is a partial cutaway plane view of further embodiment according to the invention, wherein an eccentric weight with projections is engaged in a club shaft by inserting the projections along with L-shaped guide grooves provided on the inside wall of the club shaft;
FIG.6 is the longitudinal front elevation view of the embodiment shown in FIG.5; and
FIG.7 is the perspective view of a cylindrical eccentric weight having a cutaway.

Throughout the invention, reference numeral 1 designates club shaft; 2, club head; 3, grip; 4, eccentric weight; 5, attaching member; 6, screw; 7, projection; and 8, L-shaped guide groove.
FIG.1 shows a standard-type golf club, wherein reference numeral (1) designates a club shaft provided with club head (2) at one end and grip (3) at the other end.
In the standard-type golf club, when directions along and transverse to club shaft (1) are represented with symbols "X" and "Y" respectively, the center of gravity in Y-direction is usually not located on club shaft (1) but located at a side where club head (2) projects.
The present invention is to locate the center of gravity in Y-direction substantially onto club shaft (1) by cancelling a weight eccentricity with the attachment of eccentric weight (4). For example, as shown in FIG.2, eccentric weight (4) composed of heavy part (4a), such as that of metal, and light part (4b), such as that of plastic, is tapered into cork shape, plugged into a larger end of club shaft (1) in such manner that heavy part (4a) is located at a side opposite to head (2) with respect to club shaft (1), and covered with grip (3). Thus, the center of gravity in Y-direction can be shifted substantially onto club shaft (1).
An appropriate weight of eccentric weight (4) is at a level where its attachment to a larger end of club shaft (1) cancels a weight deviation in Y-direction to bring the center of gravity in Y-direction substantially onto club shaft (1). The weight is usually approximately equal to that of club head (2) or slightly heavier than it, dependently on the attachment point and volume ratio of heavy part (4a) to light part (4b). Desirably, eccentric weight (4) is prepared into the possible compactest shape by using in heavy part (4a) a material with a relatively high density, such as lead, so that eccentric weight (4) does not hinder a desired playing action.
The method to attach eccentric weight (4) can be freely chosen. Now explaining several embodiments that are different from the above one, FIG.3 shows an embodiment wherein eccentric weight (4) is first allowed to contact with a larger end of club shaft (1) in such manner that heavy part (4a) is located at a side opposite to club head (2) with respect to club shaft (1), then covered with grip (3). In order to appropriately retain such contact, eccentric weight (4) can be attached to club shaft (1) by using an adhesive. Alternatively, eccentric weight (4) can be attached to the end of club shaft (1) by first providing eccentric weight (4) inside grip (3), then attaching grip (3) to club shaft (1).
FIG.4 shows another embodiment according to the invention, wherein a larger end of club shaft (1) is inserted in cylindrical attaching member (5) bearing eccentric weight (4) on its inside bottom, and then suitably stopped with screw (6) in such manner that heavy part (4a) is located at a side opposite to club head (2) with respect to club shaft (1). This embodiment can be advantageously used in conventional golf club.
FIGs.5 and 6 show still another embodiment according to the invention, wherein eccentric weight (4) in rod shape is provided by eccentrically covering heavy part (4a) with light part (4b). Projections (7)(7) are provided on opposite outsides of eccentric weight (4), while L-shaped guide grooves (8)(8) are provided inwardly on the inside wall of club shaft (1). Eccentric weight (4) is engaged with club shaft (1) by inserting projections (7)(7) along with guide grooves (8)(8) in such manner that heavy part (4a) is located at a side opposite to club head (2) with respect to club shaft (1).
FIG.7 shows further embodiment according to the invention, wherein eccentric weight (4) is provided by shaping a heavy plate acting as heavy part (4a), such as that of metal, into a ring having a cutaway. The cutaway can be removably filled with light part (4a) of a light material, and then, if necessary, covered with a cloth or an adhesive tape to improve its appearance and/or handleability.
Eccentric weight (4) is equipped to a golf club by first inserting a slenderer part of club shaft (1) in eccentric weight (4) through the cutaway, then moving eccentric weight (4) towards a larger end of club shaft (1), prior to its use.
Alternatively, band-shaped eccentric weight (4) of a flexible material, such as lead, can be wound around grip (4).
Although in the above embodiments an eccentric weight is attached near to the grip of a golf club, the eccentric weight can be attached in other way, as long as such attachment does not hinder a desired playing action.
As described above, since in the present invention the center of gravity in a direction vertical to a club shaft is located substantially on the club shaft, the present invention is free of the drawback that the head weight tends to slip the grip point when swung up.
Furthermore, the present invention is characterized in that, when swung down, the head weight helps to appropriately orient a golf ball as well as to increase its flying distance.
The present invention exerting such remarkable effects would make a significant contribution to the art.

Claims

1. A golf club comprising a club shaft provided with a club head at one end and a grip at the other end,
wherein the center of gravity in a direction transverse to the club shaft is located substantially on the club shaft.

2. A golf club according to claim 1, wherein the center of gravity in a direction transverse to the club shaft is located substantially on the club shaft by equipping an eccentric weight to the club shaft.

3. A golf club according to claim 1, wherein the center of gravity in a direction transverse to the club shaft is located substantially on the club shaft by equipping an eccentric weight comprising a heavy part and a light part to a larger end of the club shaft in such manner that the heavy part is located at a side opposite to the club head with respect to the club shaft.

4. A golf club according to claim 1, wherein the center of gravity in a direction transverse to the club shaft is located substantially on the club shaft by plugging an eccentric weight in cork shape comprising a heavy part and a light part into a larger end of the club shaft in such manner that the heavy part is located at a side opposite to the club head with respect to the club shaft; and covering the eccentric weight and the end of the club shaft with the grip.

5. A golf club according to claim 1, wherein the center of gravity in a direction transverse to the club shaft is located substantially on the club shaft by allowing an eccentric weight comprising a heavy part and a light part to contact with the larger end of the club shaft in such manner that the heavy part is located at a side opposite to the club head with respect to the club shaft; and covering the eccentric weight and the end of the club shaft with the grip.

6. A golf club according to claim 1, wherein the center of gravity in a direction transverse to the club shaft is located substantially on the club shaft by inserting into the larger end of the club shaft a cylindrical attaching member bearing an eccentric weight comprising a heavy part and a light part in such manner that the heavy part is located at a side opposite to the club head with respect to the club shaft.

7. A golf club according to claim 1, wherein the center of gravity in a direction transverse to the club shaft is located substantially on the club shaft by preparing a flexible plate member into a ring having a cutaway; inserting the club shaft in the ring through the cutaway; and moving the ring towards the larger end of the club shaft.

8. A golf club according to claim 1, wherein the centre of gravity in a direction transverse to the club shaft is located substantially on the club shaft by providing an eccentric weight comprising a heavy part and a light part and having projections on its opposite outside; and inserting the projec tions along with guide grooves, provided inwardly on the inside wall of of the club shaft, in such manner that the heavy part is located in a side opposite to the club head with respect to the club shaft.