Symmetrical Golf Club Head With Center Of Gravity Coincident With Geometric Center

Abstract

A wood type gold club in which the head is comprised of a molded, high impact, plastic material of uniform density and is homogenous throughout, both as regards density and weight, embodies similarly lofted front and rear faces, has its geometric center coinciding with its center of gravity, is symmetrical with respect to a vertical plane passing centrally and longitudinally therethrough and also through the axis of the shaft, and is so constructed, dimensioned, shaped and proportioned that when the club is supported in pendulum fashion from the proximate end of the club shaft, the plumb line axis passes through the common or coincident geometric center and center of gravity of the head.

Description

The present invention relates generally to golf clubs and has particular reference to a "wood" type (driver, brassie, spoon, etc.) golf club in which the club head is molded from a uniform density, molded, high impact, plastic material, the club head per se having novel symmetrical dimensional characteristics, and the golf club in its entirety being balanced in a particular manner so as to impart thereto inherent performance attributes which hitherto have not been attained with conventional or previously designed "wood" type golf clubs.

Insofar as the use of a non-organic, high-impact plastic material for the body of the golf club head is concerned, it has been found that organic material such as wood, even when the best grade is employed, will vary in its characteristics over a period of time. The center of gravity of the club head may shift slightly, either with aging or with temperature differentials. Changes in density also may occur especially if the club head is exposed to moisture over a relatively short period of time, such, for example, as when the club is used in heavy dew or on wet turf. Splitting and surface defects are also known to occur due to repeated impact blows. By the use of a uniform density, high impact, plastic resin such as moldable polystyrene or other suitable plastic material, these difficulties are obviated.

Insofar as the use of a symmetrical golf club head is concerned, this feature insures that with the normal aim and swing of an experienced golfer, the point of ball impact will lie at a point on the club face where there will be no unbalanced reaction forces on either side of such points, either outwardly or inwardly thereof.

Insofar as golf club balance is concerned, according to the present invention, the club shaft and the club head are so designed and related to each other than when the club is supported in pendulum fashion from the proximate or upper end of the shaft, the plumb line axis resulting therefrom passes through the common geometric center and the center of gravity of the club head. By such an arrangement, when this feature is embodied in any given set of "wood" type golf clubs having substantially or approximately equal shaft lengths, there will be no deviation in the point of ball impact with the face of the clubs when such clubs are used by the same player with the same proper aim and swing.

The provision of a golf club such as has been briefly outlined above and possessing the stated advantages constitutes the principal object of the invention.

Other objects and advantages of the invention, not at this time enumerated, will become readily apparent as the nature of the invention is better understood from a consideration of the following detailed description.

The invention consists in the several novel features which are hereinafter set forth and are more particularly defined by claims at the conclusion hereof.

In the accompanying single sheet of drawings forming a part of this specification one illustrative embodiment of the invention is shown.

In these drawings:

FIG. 1 is a front perspective view of the head of a golf club embodying the principles of the present invention;

FIG. 2 is a top plan view of the golf club head of FIG. 1;

FIG. 3 is a front view of the golf club head of FIG. 1;

FIG. 4 is a bottom plan view of the golf club head of FIG. 1;

FIG. 5 is an end view of the golf club head of FIG. 1 looking in the direction of the toe portion of the club;

FIG. 6 is an opposite end view of the golf club head of FIG. 1 looking in the direction of the heel portion of the club;

FIG. 7 is a reduced vertical transverse sectional view taken on the line 7--7 of FIG. 1;

FIG. 8 is a top view view of a complete golf club embodying the head of FIG. 1 and showing the same in a pendulum-balanced position;

FIG. 9 is a front view of the balanced golf club of FIG. 8; and

FIG. 10 is a rear view of the golf club head of FIG. 3.

Referring now to the drawings in detail and in particular to FIGS. 8 and 9, a "wood" type golf club embodying the present invention is designated in its entirety by the reference numeral 10 and is comprised of a horizontally elongated head 12, a shaft 14, and an elongated straight hosel 16. The hosel is formed integrally with the heel portion of the head 12 and as clearly shown in FIG. 3 of the drawings, it extends upwards and outwards therefrom at an angle of approximately 60.degree. with respect to the horizontal when the head 12 is soled as shown in FIGS. 3, 5, 6, 7 and 10 of the drawings. It is upwardly tapered and has an axially extending socket or bore (not shown) for snugly receiving the lower distal end of the shaft 14. The head is formed of a suitable high impact, uniform density, molded plastic material such as polystyrene, or other similar materials having suitable hardness and toughness sufficient to withstand the impact of a golf club when striking the same, as well as having a desirable infinitesimal degree of elasticity. It is contemplated that the head will be solid throughout its mass and of uniform density throughout. As best illustrated in FIGS. 2, 4 and 7, the head 12 is for all intents and purposes symmetrical with respect to a vertical plane passing centrally and longitudinally therethrough and also through the axes of the shaft 14 and the hosel 16 and, in addition, is provided with a substantially flat conditioned striking face 18 at the front thereof and a substantially flat non-conditioned rear face. The head 12 is further formed with a rounded toe 20, a substantially flat or planar bottom face 22, a rounded or convexly curved, heel 24, and a substantially flat top face 25, The shaft 14 and the hosel 16 are coaxial and the lower or distal end of the shaft is surrounded by a protective sleeve 26 which surmounts and forms an upper continuation of the hosel 16. As best shown in FIGS. 2, 5, 6 and 7, the substantially flat striking face 18 and the non-conditioned rear face 19 are each spaced equidistantly throughout its length from the aforementioned imaginary vertical plane which passes centrally and longitudinally through the head and also the common axes of the shaft 14 and the hosel 16. The sole or bottom surface face 22 is recessed to accommodate a metallic sole plate 30. The latter is generally hourglass-shaped in profile and is fixedly and removably held in position within the recess by screws 32 (see FIG. 4). As illustrated in FIG. 4, the sole plate 30, like the head 12, is symmetrical with respect to a vertical plane passing centrally and longitudinally through the head 12 and also through the axes of the shaft 14 and the hosel 16. In other words, the two end portions of the sole plate are exactly the same in size, shape and thickness and the narrow central portion of the sole plate is disposed in intersecting relation with the aforesaid imaginary plane.

The front striking face 18 of the head 12 is provided with friction or ball-spinning striations or other surface interruptions, the illustrated interruptions being in the form of a series of equally spaced apart, vertical grooves 34 and a series of equally spaced apart horizontal grooves 36 in intersecting relation with the vertical grooves, the checkerboard intersection of such grooves representing the striking area of the front striking face as shown in FIG. 9 of the drawings, the area which is formed by the intersecting vertical and horizontal grooves is located in the central portion of the lofted front striking face 18 of the club head 12 and is symmetrically arranged with respect to the hereinafter mentioned coincident geometric center and center of gravity of the club head 12. The angle or slope of the striking face 18 with respect to the sole or bottom face 22 of the head 12 may vary according to the desired loft, but in any event, the slopes or lofts of the front striking face 18 and the non-conditioned rear face 19 are exactly the same. If the head is to be used by a left-handed player, the striking face 18 and the non-conditioned rear face 19 will be reversed.

As best seen in FIG. 1, the over-all shape of the head proper is of bulbous design and of such a character that the planes of the faces 18 and 19 intersect the generally rounded body of the head and thereby assume a generally triangular outline with rounded corners, the bottom corner presenting a radius of curvature which is appreciably greater than the radii of curvature. The neck 26 is generally of frusto-conical shape and tapers smoothly upwardly into the outline of the hosel 16, the latter smoothly tapering into the cylindrical outline of the shaft 14.

The shaft may be of any conventional design, and in the illustrated form of shaft 14, it is provided at its upper end with the usual hand grip 40 which is coaxial with respect to the remainder of the shaft and the details of which may vary widely and form no part of the present invention.

Because of the fact that the head 12 of the golf club 10 is solid, is symmetrical with respect to a vertical plane passing centrally and longitudinally through the head also through the axes of the shaft 14 and the hosel 16, and is of uniform density throughout, the geometric center of the club head and the center of gravity of the head are coincident. Additionally, because FIG. 7 is a sectional view which is taken transversely through the head 12 on a vertical plane that intersects this common or coincident geometric center and center of gravity, this center becomes exposed and it is possible to designate the same by a point which is appropriately labelled in this view or figure of the drawings.

According to the present invention, the golf club 10 as a whole is so constructed, dimensioned, shaped and proportioned that when the club is freely suspended as illustrated in FIGS. 8 and 9 from the upper or proximate end of the shaft 14, an imaginary plumb line axis such as is schematically shown by a dotted line and labelled as such, passes through the aforementioned common or coincident geometric center and center of gravity of the head. In FIG. 8 where the golf club is viewed from the top, the plumb line axis visibly intersects said common geometric center and center of gravity of the head. Also in FIG. 9 where the golf club is viewed from the side, the plumb line axis also visibly intersects said common centers.

From a mathematical and physical point of view, it is obvious that by varying the length of the shaft 14 with the size, shape and mass of the club head 12 remaining the same, slight deviations of the plumb line axis from said common geometric center and center of gravity of the club head 12 will take place. However, such deviations are practically negligible when the variations in shaft length fall within conventional golf club shaft lengths. To effect an appreciable deviation of the plumb line axis in such a manner as to defeat the intent of the present invention, the shaft would have to be shortened to no less than one-half of the length of the shortest practical shaft length, or lengthened to many times such a practical shaft length.

Because of the aforesaid symmetrical arrangement of the present golf club head, and particularly because of the fact that a plumb line axis will pass through the common or coincident geometric center and the center of gravity of the golf club head 12, an additional test for accurate club symmetry and balance is available and is predicated upon ballistic principles. This test consists in suspending the balanced club of the present invention by a string of predetermined length and torsion resistance from the exact center of the upper end of the shaft 14, and similarly suspending a non-balanced or conventional club from a second string of the same length and torsion resistance. Thereafter, both clubs are rotated in the same direction a large number of equal turns until both strings are under high torsion. The two clubs are then released simultaneously and allowed to "spin out." Due to the unbalanced condition of the non-balanced or conventional club, eccentric forces are set up during the spin-out operation and since there are no unbalanced forces in connection with the balanced club of the present invention, obviously the rate of string "unwind" will be greater where the latter club is concerned. At the precise moment that the balanced club begins to reverse its direction of rotation due to a reverse wind occasioned by club mass momentum, it will be found that the unbalanced club is either still unwinding or has entered into its period of rewind.

With a golf club such as that which is illustrated and described herein, a properly aimed and executed stroke of the golf club 10 will invariably result in the ball being struck at the optimum point of impact on the used lofted striking face 18 where there will be no unbalanced reaction forces tending to turn the club to one side or the other and thereby, as a consequence, the full force of the impact will be applied to producing straight-forward ball velocity in flight. By changing the slope or loft of the front striking face 18 and the non-conditioned rear face 19, a different kind of "wood" type golf club will be produced without any variation in the normal swing of the club and the player is not required to change or adjust his or her swing. With the present particular constriction of the golf club, the user will be induced to hit the ball on that portion of the striking face that gives maximum or best results namely, the restricted area which is formed by the intersecting vertical and horizontal grooves 34 and 36.

Claims

Having thus described the invention what I claim as new and desire to secure by Letters Patent is:

1. As a new article of manufacture, a golf club comprising a straight, normally upstanding shaft having an upper proximate end and a lower distal end, and a symmetrical, horizontally elongated "wood" type head at the distal end of the shaft, said head being formed throughout of molded, high impact, plastic material of uniform density and embodying toe and heel portions at its opposite ends, a substantially flat bottom face, and an integrally formed, upwardly and outwardly extending hosel on its heel portion, said shaft having the distal end thereof connected to said hosel and being disposed in coaxial relation with the latter, said head also embodying a substantially flat and lofted front striking face and a substantially flat rear face with a loft the same as the loft of the front striking face, said front and rear faces being symmetrical with respect to a vertical plane passing centrally and longitudinally through the head and the common axes of said shaft and hosel, and, in addition, being each spaced equidistantly from said plane throughout its entire length, said head being designed so that its geometric center and its center of gravity are coincident and lie in the aforementioned plane, said golf club as a whole being constructed, dimensioned, shaped and proportioned so that when it is freely suspended from the upper proximate end of the shaft a plumb line axis passing through the point of suspension will intersect said coincident geometric center and center of gravity of the head.

2. A golf club according to claim 1 and having, additionally, a sole plate positioned and secured in a correspondingly shaped recess in said bottom face of the head, embodying a generally hourglass shape, having end portions of exactly the same shape and size, and positioned so that its end portions lie on opposite sides of said plane to the end that the sole plate is symmetrical with respect to the plane.

3. A golf club according to claim 1 and wherein the lofted front striking face of the head has in the central portion thereof a restricted area which is formed by a series of spaced apart vertical grooves and also a series of spaced apart horizontal grooves arranged in intersecting relation with the vertical grooves and forming therewith a checkerboard pattern, said checkerboard pattern being symmetrically arranged with respect to the coincident geometric center and center of gravity of the head.