Golf Club Head Of The Iron Type Having A Concave Sole

Abstract

A golf club of the iron type having a novel golf club head comprising a striking face with a leading lower edge, a toe, a heel, and a novel concave sole; said concave sole imparting improved ball striking characteristics such as improved dynamic stability of the head in contact with the ground and minimize deceleration of the club head speed in contact with the ground. The golf head is useful for the manufacture of golf clubs of the iron type.

Description

FIELD OF INVENTION

This invention relates to golf clubs and more particularly to a golf club of the "iron" type having a novel golf club head with a concave sole.

BACKGROUND OF THE INVENTION

It is well known in golf, a game of skill, that the golfer's accuracy is dependent upon the golf club head speed and the relationship of the golf ball and the club striking face at the point of impact.

The accepted technique in hitting the ball from sand requires the club head entering the sand some distance behind the ball, the face of the club continuing through the ball with such direction and force so as to propel the ball onto the green or putting surface. This is known as the explosion or sand shot. All other shots in golf require that the object ball be struck with the hitting surface or face of the club prior to the leading edge of the face entering the media upon which the ball rests. Any departure from this technique results in the loss of objective.

I have invented a golf club having a novel golf club head with a concave sole which provides greater accuracy than is obtainable with conventional golf clubs. My golf club is particularly useful for golf clubs of the "iron" type and more particularly for the golf club known as the sand wedge and the like used to impart a high loft or arc of trajectory to a golf ball.

SUMMARY OF THE INVENTION

This invention is directed to a golf club of the "iron" type comprising a shaft and a head; said head having a striking face with a leading lower edge; a toe; a heel; a sole extending rearwardly from said lower edge between said toe and heel to provide a first downwardly facing surface generally parallel to and immediately behind said lower edge; a second downwardly facing concave surface as viewed from below extending rearwardly from said first surface; and a third downwardly facing surface having a lowermost portion extending rearwardly from said second surface; said second surface having a width that is greater than the width of said first surface plus the width of said third surface forward of said lowermost portion, said widths being measured in a plane passing through and perpendicular to a central portion of the striking face.

The golf club of this invention is of the "iron" type comprising a shaft and a head; said head having a lofted striking face with a rear side and a leading lower edge on said face; a toe; a heel; a sole extending rearwardly from said lower edge between said toe and heel to provide a first downwardly facing surface generally parallel to and immediately behind said lower edge; a flanged portion extending rearwardly from said rear side having a second and third downwardly facing surfaces, said second surface being formed by a cavity between said first and third surfaces and having a width which is greater than the width of the first surface plus the width of the third surface forward of the lowest portion of the third surface.

BRIEF DESCRIPTION OF THE DRAWINGS

In the attached drawings wherein preferred embodiments of the invention are illustrated:

FIG. 1 is a schematic view of the action of club head through said media upon which the ball rests;

FIG. 2 is the front elevational view of a lofted golf club of the lofted type, i.e., sand wedge golf club head embodiment of this invention;

FIG. 3 is a top plan view of said sand wedge;

FIG. 4 is a bottom plan view of said sand wedge;

FIG. 5 is a rear elevational view of said sand wedge;

FIG. 6 is a right elevational view of said sand wedge;

FIG. 7 is a cross-sectional view of said sand wedge taken along lines 7 -- 7 of FIG. 2;

FIG. 8 is a bottom plan view of an alternate golf club head construction;

FIG. 9 is a rear elevational view of the embodiment shown in FIG. 8;

FIG. 10 is a cross-sectional view taken along line 10 -- 10 of the golf club head shown in FIG. 8;

FIG. 11 is a side elevational view of an alternate modification of the golf club head of this invention; and

FIG. 12 is a side elevational view of another alternate modification of the golf club of this invention.

Referring to the drawings and more particularly to FIG. 1 to 7, the golf club 10 comprises a tubular shaft 28 having a hand grip 32 at the upper end of the shaft and the novel golf club head 12 at the other end of the shaft. The golf club head is attached to the shaft by a concentric coupling element 30. The club head which is composed of metal can be produced by well known casting, or investment casting techniques. The club head has a heel 35, a toe 34 and a striking face 14 with a leading lower edge 16, a sole extending rearwardly from said leading lower edge between said toe and heel and consisting of a first downwardly facing surface 17, which is generally parallel to and immediately behind said lower edge, having a lowermost portion 18; a second downwardly facing concave surface 20 extends rearwardly from said first facing surface and a third downwardly facing surface 24 having a lowermost portion 22, said third surface extending rearwardly from said second surface. The lowermost portion 18 of the first downwardly facing surface can be considered to be a second lower edge at the intersection of the first facing surface and the concave surface and the lowermost portion 22 of the third downwardly facing surface can be considered to be a third lower edge at the intersection of the third facing surface with the concave surface. An optional feature of the club head is a groove 38 by which the weight of the club head is controlled by varying the depth of the groove; said groove extending upwardly from said third surface to the uppermost portion of the striking face.

In essence, the novel sole of my golf club head comprises a lofted striking face with a rear side and a leading lower edge on said face; a toe; a heel; and a sole extending rearwardly from the lower edge between the toe and heel to provide a first downwardly facing surface generally parallel to and immediately behind the lower leading edge, with a flanged portion extending rearwardly from said rear side. The flanged portion which extends rearwardly from the rear side, comprises a second and third downwardly facing surface said second surface being formed by a cavity between the first and third surfaces. The cavity has a width which is greater than the width of the first surface plus the width of the third surface forward of the lowest portion of the third surface.

The ratio of the width of the cavity to the sum of the width of the first and third surfaces is 2:1 to 10:1 or more and preferably 3:1 to 8:1 and most preferred 3:1 to 5:1.

The club head is attached to the shaft by a cylindrical shank 26 extending from the heel of the club which has a hollow portion 40 for being adapted to the shaft.

The striking face contains a plurality of grooves 26 which assist imparting spin to a golf ball 15 which has been struck.

FIG. 1 shows the action of a lofted embodiment of the golf club of this invention through sand and in phantom from the club before striking the ball and after striking the ball. The leading edge of the moving club head meets the ground before lower edge 22. The leading edge and lower edge 22 of the golf club prior to, during, and after striking the golf ball forms path A and B as arcs of two concentric circles. Preferable, at about the middle of the striking face, the angle formed by a line passing through the leading edge perpendicular to the golf club shaft and the line drawn from the leading edge and edge 22 forms an angle a of up to about 25.degree., preferably in the range of 7.degree. to 15.degree., and most preferred is an angle in the range of 7.degree. to 12.degree..

Restated another way, a line drawn in a plane perpendicular to a center portion of said face from the lowermost portion of the third surface to the lower leading edge with the shaft when viewed rearwardly forms an obtuse angle .alpha. shown in FIG. 11 which is within the range of 90.degree. to 115.degree. more or less when viewed rearwardly, and preferably 90.degree. to 105.degree. and most preferred 92.degree. to 95.degree..

In FIG. 7, the concavity is described distance e from the bottom of the concavity to a line joining edges 18 and 22 and the distance d between 18 and 22. Preferably, the ratio of d to e is 4 to 1 to 15 to 1 and most preferred 6:1 to 10:1. The length of the distance d preferably is 0.5 to 1.5 inches or longer and most preferred 0.75 to 1.25 inches.

The concave surface on the sole of the club can be any section of a quadric or conic surfaces of revolution provided the longitudinal axis of the surface lies essentially parallel to the leading edge. The second surface, for example, can be the top portion of a hemisphere, a spheroid, an ellipsoid, and a sphere or a spheroid cut with a cylinder or a series of cylinders or a curved cylinder to form a quadric surface or a conic surface of revolution. The surface when it is a section of a cylinder is positioned so that the longitudinal axis of the cylinder lies essentially parallel to the lower leading edge. Alternately, the longitudinal of the cylinder can be curved with the center of curvature lying at a point behind the striking face of the golf club. Thus the surface as showing in FIG. 5 is a section of a cylinder and in FIG. 4 and FIG. 7 the surface is an ellipsoid. In FIG. 7, the cross-sectional surface of the club head is shown as 42.

In FIG. 8 to 10 the golf club head 12-A shows the modification of the invention where the concave surface is an ellipsoid. The club head consists of a shank 26-A, having a hollow portion 40-A for connection with the golf club shaft, a toe 34-A, a striking face 14-A, with a leading edge 16-A, a sole extending rearwardly from said leading lower edge between the toe and heel and consisting of a first downwardly facing surface 17-A which is generally parallel to and immediately behind the lower edge and having a lowermost portion 18-A, a second downwardly facing concave surface 20-A extending rearwardly from said first facing surface and a third downwardly facing surface 24-A having a lowermost portion 22-A extending rearwardly from the second surface. Optionally, the club can have a weight compensating groove 38-A which extends from the uppermost portion of the third surface to the uppermost portion of the striking face, a cross-sectional surface of the club 42-A.

The relationship of the various surfaces to each other in the alternate embodiment shown in FIG. 8, 40 and 11 are the same as described above for the club described in FIG. 1 -7.

The modification of the golf club in this invention for a less lofted club 12-C is shown in FIG. 12 comprising a shank 26-C, a toe 34-C, a striking face 14-C with a lower leading edge 16-C, with a sole extending rearwardly from said leading lower edge between said toe and heel and consisting of a first downwardly facing surface 17-C which is generally parallel to and immediately behind said lower edge having a lowermost portion 18-C; a second downwardly facing concave surface 20-C extends rearwardly from said first facing surface and a third downwardly facing surface 24-C having a lowermost portion 22-C extending rearwardly from said second surface. The lowermost portion 18-C of the first downwardly facing surface can be considered to be a second lower edge at the intersection of the first facing surface and the concave surface and the lowermost portion 22-C of the third downwardly facing surface can be considered to be a third lower edge at the intersection of the third facing surface with the concave surface. An optional feature of the club head is a groove 38-C by which the weight of the club head is controlled by varying the depth of the groove; said groove extending upwardly from said third surface to the uppermost portion of the striking face.

Another modification of the golf club is shown in FIG. 11 comprising a cylindrical shank 26-B, a toe 34-B, a striking face 14-B having a lower leading edge 16-B, a concave surface 20-B and a third surface 24-B. FIG. 11 shows a golf club used for more lofted shots than the club of FIG. 12, but less lofted than the club of FIG. 7. Optionally, a weight compensating groove 38-B which can be of varying depth, extends from the uppermost portion of the lowermost portion of the third surface to the uppermost portion of the rear side of the striking face.

The ratio of the width of the lower flange to the width of the flat sole is 1:2 to 1:10 or greater and preferably 1:3 to 1:8 and most preferred 1:3 to 1:6. The first and third surfaces have a width of 1/8 to 5/16 inch or more and preferably 3/8 to 1/4 inch, and are not necessarily the same width.

The leading edge can be straight or curved, with the center of curvature being located at a point behind the striking face. The longitudinal axis of the concavity is essentially parallel to the straight leading edge or to the tangent to the curved leading edge at a point near the midpoint of the striking face.

By a golf club of the "iron" type it is meant the club consisting of a metal head having the striking face related to the shaft that it slopes upwardly and rearwardly when the sole of the club is parallel to the ground and the shaft is held vertically.

The golf club of this invention with the novel golf club head unexpectedly improves the accuracy of a person's golf game using the same. It is believed that the design of my club, particularly for the lofted clubs, can be used to more easily propel a golf ball along a path of desired trajectory and distance because of the improved dynamic stability of the head of the club in the media upon which the golf ball rests and because of the minimization of the rate of deceleration of the speed of the golf club head upon entry into and passage through said media.

A sand wedge such as has been described herein has all the embodiments required of the so-called pitching wedge. Conversely, a pitching wedge to be effective need not have the embodiments required of the sand wedge. United states Golf Association rules require that a contestant carry no more than 14 clubs in his bag during sanctioned tournament. Therefore, a club effective for both pitching and sand is desirable. Such latitude is intended within the scope of my invention. The foregoing detailed description has been provided for clarity of understanding only and no unnecessary limitations are to be understood therefrom. The invention is not limited to the exact details shown and described for obvious modifications will occur to those skilled in the art.

Claims

The preferred embodiments in which an exclusive privilege or position is claimed are as follows:

1. A golf club iron comprising a shaft with a metal head secured thereto at one end thereof, a substantially planar ball striking face inclined upwardly and rearwardly from a front ground penetrating edge portion to an uppermost rear portion, the major portion of the ball striking face being rearward of a reference plane containing the axis of the shaft and extending generally parallel to the front edge portion of the ball striking face, a downwardly facing sole rearward of the front edge portion of the ball striking face, a back face extending between the sole and the uppermost rear portion of the ball striking face, and shallow concavity in the major portion of the sole gradually curving in a direction generally transverse to the reference plane, the concavity having a leading boundary portion spaced from the front edge portion and forming a first sole portion, the leading boundary portion forming a first sole portion edge, the first sole portion edge being the lowermost elevation of the first sole portion, the concavity having a trailing boundary portion spaced from the back face and forming a second sole portion, the trailing boundary portion terminating at a second sole portion edge, the second sole portion edge being the lowermost elevation of the second sole portion, and the second sole portion edge being the lowermost elevation of the sole when the reference plane is vertical.

2. A golf club iron as in claim 1 wherein a line interconnecting the first and second sole portion edges forms an angle of 90.degree. to 115.degree. with the vertical.

3. A golf club iron as in claim 2 wherein the angle is in the range of 92.degree. to 95.degree..

4. A golf club iron as in claim 1 wherein the shallow concavity is defined by the uppermost portion of a cylinder having a longitudinal axis generally parallel to the front edge portion of the ball striking face.