US 3819190 A
A golf ball having controllable flight characteristics and comprised of a standard sized spherical body with surface depressions located in a band extending therearound and the surface portions outside this band having fewer, or no, depressions to decrease the drag on the ball while leaving the lift characteristics substantially the same thereby to cause the ball, for a given striking force, to exhibit directional control.
Claims available in
Description (OCR text may contain errors)
United States Patent [191 Nepela et al.
l ll June 25, 1974 GOLF BALL  Inventors: Daniel A. Nepela, 18960 Fernbrook Ct., Saratoga, Calif. 95070; Fred E. Holmstrom, 6520 Falls River Dr., San Jose, Calif. 95120  Filed: Oct. 2, 1972  Appl. No.: 294,363
 US. Cl. 273/232, 273/183 C  Int. Cl A6311 37/14  Field of Search 273/232, 213, 199, 235,
 References Cited UNITED STATES PATENTS 2,135,210 11/1938 Farrar 273/232 FOREIGN PATENTS OR APPLICATIONS 904,785 8/1962 Great Britain 273/213 Primary Examiner-George J. Marlo Attorney, Agent, or Firm-Gerald L. Moore  ABSTRACT A golf ball having controllable flight characteristics and comprised of a standard sizedl spherical body with surface depressions located in a band extending therearound and the surface portions outside this band having fewer, or no, depressions to decrease the drag on the ball while leaving the lift characteristics substantially the same thereby to cause the ball, for a given striking force, to exhibit directional control.
5 Claims, 5 Drawing Figures mu 1 9 l 8 3 PATENTEDJUNZSIHM FIG. 2
GOLF BALL BACKGROUND OF THE INVENTION This invention relates to an improvement in a golf ball having as its primary purpose the making of a golf ball that will travel substantially the same distance as a conventional ball while giving the player more control over the direction the ball travels.
Golf balls used today comprise a spherical body made of a solid resilient material. The outer layer of the ball is dimpled to form depressions to increase the lift forces imparted on the ball when it is hit. When properly struck, the ball will rise in flight and spin about a horizontal axis such that the bottom of the ball moves in the direction of flight and the top moves opposite to the direction of travel. imparting lift to the ball requires that a film of air immediately adjacent the ball surface spins with the ball. This air film at the top of the ball is moving in the same direction as the air passing over the ball and thereby serves to increase the velocity of the air at that point. Thus the air pressure at the top surface of the ball is lower than elsewhere on the ball. At the same time the air film at the bottom of the ball is reacting against the ambient air flow in a manner to slow the passing air and increase the pressure at that point. The result is a greater atmospheric pressure at the bottom of the spinning ball than at the top, thereby supplying a lifting force tending to carry the ball farther.
As a golf club impacts with a conventional golf ball on the ground, or on a tee, two effects occur. (I) The ball acquires translational velocity in the intended direction, and (2) the ball spins about an axis of rotation. The direction the axis of spin takes, or is'given with respect to the ground and the amount of spin imparted to the ball are the primary factors in determining what, if any, additional range may be acquired by the ball or whether it will hook or slice upon leaving the club.
In general, the lifting force increases if the ball spins faster during flight. However, the spin speed imparted to the ball is substantially constant for each golf club and a given tee height. An important factor affecting the lift is the thickness of the boundary film of air spinning with the ball. To increase this thickness, dimples or depressions are formed in the ball surface which cause localized areas of turbulence. Turbulence tends to increase the thickness of the air film spinning with the ball thereby increasing the lifting forces imparted on the ball.
However, a negative effect is realized also when a dimpled surface is utilized. The force tending to slow a conventional ball as it travels through the air is commonly referred to as drag. The drag is proportional to the planar area of the ball pushing through the air. With the air film spinning with the ball, the effective planar area of the ball is increased thereby increasing the drag forces imparted on the ball. Naturally any detrimental forces acting to slow the ball in flight will reduce the distance the ball travels. I
One other detrimental effect of increasing the lift of the ball occurs when the ball is hit imperfectly, which act results all too often with the average golfer. In hitting the ball, if the club face is not traveling in the same direction it is desired for the ball to take, i.e., with the planar surface normal to that direction, a sidewise spin is imparted to the ball causing forces to act thereon similar to those imparting lift. In this manner the ball is forced to one side or the other of the intended flight path resulting in a curved flight commonly called a hook or slice depending on the direction of the spin. Some golfers more expert at the game use an intentional hook or slice to improve theirgame, but most golfers attempt to hit the ball straight for best results.
It is the primary objective of this invention to provide a golf ball with substantially the same range as a conventional ball but incorporating a depression design on the surface of the ball that can be oriented on the tee, or with respect to the axis of spin, so that as the ball spins in flight, the lift, hook or slice properties of the ball are influenced.
SUMMARY OF THE INVENTION A golf ball including a cover having the depressions therein centered adjacent a single plane passing through the geometric center of the ball in a manner to affect the air flow past the ball during flight and render control over the direction of flight of the spinning ball.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a prior art golf ball having the surface depressions distributed evenly over the total surface;
FIG. 2 is a view along the lines 2-2 of FIG. 1;
FIG. 3 shows one preferred embodiment of the invention wherein dimple type depressions are positioned in a band about a circumferential line extending around the ball;
FIG. 4 shows another preferred embodiment of the invention wherein the surface depressions comprise grooves extending through a band portion about the ball; and
FIG. 5 shows still another embodiment wherein the total ball surface is dimpled, however, the density of the dimples is increased within a center band extending around the ball.
DESCRIPTION OF PREFERRED EMBODIMENTS In FIG. 1 is shown an example of a commonly used golf ball comprising a spherical body 10 of resilient material with the surface thereof having formed therein a plurality of evenly distributed and spaced depressions or dimples 11 provided to increase the lift on the spinning ball in flight in the manner previously described. Thus if the ball is travelling in the direction of the arrow 12 the natural back spin imparted to the ball at the impact of the club (not shown) and the ball will be in the direction of the arrow 13 about a spin axis 14 extending out of the plane of the drawing.
Referring now to FIG. 2, the ball of FIG. 1 is shown spinning in a direction with the surface being seen travelling downward relative to the drawing and with the ball travelling in a direction into the paper. The spin axis is shown as the dotted line 14 extending through the geometric center of the ball.
To illustrate the net atmospheric force tending to lift the ball, two arrows are drawn extending in a direction normal to the ball surface. Arrow 15 illustrates a lifting force acting on the bottom of the ball and resulting from the interaction of the film of air spinning with the ball as heretofore described. Arrow 16 illustrates a downward pressure imparted in the ball having a smaller force (as shown by the length of the arrow) than the lifting force thereby resulting in a resultant force acting to move the ball upward in the manner previously described.
At the same instant, all the surface is being acted on by atmospheric pressure with the differences being that the total forces have less effect on the flight of the ball than do those acting on a central band about the center of the ball.
For instance, arrow 17 representing a force acting at a point close to the intersection of the ball surface and the spin axis is comprised of force arrows 18 and 19. The vertical arrow 18 indicates a slight lifting force on the ball but unfortunately most of the force consists of that indicated by the arrow 19 acting to push the ball to the side because of the location of the point at which the force acts. Of course, the sidewise direction force 19 is offset by another force acting in the opposite direction on the other side of the ball. Additionally the total force acting at this point is less than those nearer arrow since the ball surface velocity, and therefore the velocity of the air film travelling with the surface, is less than that at arrow 15.
However, the air film over the total surface is nearly uniform in thickness due to the even distribution of the dimples in the ball surface. The thickness of the air film adds to the overall drag area of the ball thereby contributing to the drag forces imparted on the ball thus tending to slow it down while in flight. The air film in the polar regions about the spin axis contribute to the drag while contributing little or nothing to the overall lift imparted on the ball.
In accordance with the present invention, the dimples or surface depressions on the ball surface are concentrated in a circumferential band centered about a circumferential line around the ball. If the ball is teed with the plane of the band aimed along the desired direction of flight, the lift characteristics of the ball remain substantially unchanged over a conventional ball since, as shown heretofore, those areas external to the circumferential band contribute little to the lift imparted on the ball when spinning about the axis 26.
By making the surface regions outside the bar d smoother, i.e. fewer dimples, less air turbulence results and a thinner film of air is carried by these areas thereby reducing the drag on the ball while not appreciably affecting the lift forces. In this manner, the lift to drag ratio of the ball is adjusted upward.
As shown in FIG. 3, a preferred embodiment of the ball of the subject invention includes a standard resillent body 20 as used in prior art devices. However dimples 21 are concentrated in a band extending about the sphere and centered about an imaginary plane represented by the dotted line 22 passing through the geometric center of the ball. The polar regions 24, and 25 are relatively smooth surfaced in this embodiment. Of course the ball could also be made with the surface depressions being more pronounced within the band but of equal density as those outside the band.
The subject ball is teed in the position shown with the band extending in a vertical plane in the direction of the intended flight of the ball. Upon being hit, the ball spins about the spin axis 26 extending through the midpoints of the polar regions 24 and 25. Lift of the ball is accomplished by the air film adjacent the dimpled band. However, only a thin air film spins adjacent to the regions 24 and 25 due to the smoother surface configuration. Thus the lift exerted on the ball is substantially the same as for the prior art ball since the areas of high lift are the same. However the drag on the ball is decreased because less air film is carried with the ball.
A further and more unexpected result occurs with the ball heretofore described and shown in FIG. 3. If by chance the ball is hit with a sidewise spin, which commonly causes a hooking or slicing direction of travel, the resulting sidewise spin will result in less curving of the flight path since less lift results from the regions 24 and 25. Thus more control over the ball is provided by the subject invention.
Tests have shown that if the ball is hit with a partial sidewise spin, the subject ball will first start the curved flight commonly called the hook or slice. The path of the ball will thereafter tend to straighten out on a line close to the intended path and cease following the curving, or arcuate, path originally caused by the sidewise spin. One further factor tending to cause this unexpected result may be the slightly greater weight at the polar regions of the ball because of the lesser density of the dimples on the ball surface. Thus, the ball exhibits what can best be described as a barbell effect; that is, the ball always attempts to spin about a longitudinal axis extending through both polar regions. As a result, the sidewise spin ceases as the ball corrects itself in flight, thereby doing away with the sidewise spin which otherwise would cause further curving of the flight path.
Upon landing, the ball will assume any of a number of positions relative to the green where it is ultimately desired to be positioned. However the shots following the tee shot usually have distance as a secondary requirement and if the ball is not aligned to provide maximum lift, little effect results. The ball will always have an equal amount of dimples and less dimpled surface area to each side of a plane passing through the geometric center and perpendicular to the spin axis such that little or no curving of the flight path results from an unaligned lie. Further, if the barbell effect does in fact correct the sidewise spin, the ball will soon assume a spin about an axis perpendicular to the axis of the dimpled band. The player need only allow for less lift if the band initially does not align with the flight path. For putting, the undimpled areas between dimples form an even spherical surface for control of the ball.
In FIG. 4 is shown another embodiment of the ball wherein the invention is incorporated in a ball 27 having central band 28 of depressions. The depressions are formed by a series of grooves 29 extending from one smooth region 30 to the other smooth region 31. The ridges 32 combine with the grooves to create turbulence thereby to increase the film of air spinning with the ball as did the depressions in the previous embodiment.
FIG. 5 illustrates still another embodiment of the invention wherein the ball 34 has dimples 35 distributed over the total surface area. However in this instance the dimples are within a center band indicated by lines 36 and 37. Thus the turbulence within this band is greatest thereby increasing the thickness of the film adjacent thereto, while that adjacent to the cap regions 38 and 39 is less thick. Thus, control of the ball is increased in the same manner as in previous embodiments with similar beneficial results.
1. A golf ball including a cover having a plurality of depressions at spaced locations on the surface thereof adapted to exert a lifting force on the ball as it spins during flight, and said depressions being located to cause greater surface air turbulence adjacent a single circumferential band extending around the ball thereby to affect the air flow therearound and render control over the direction of flight of the ball as the ball spins about an axis generally perpendicular to the plane of the band during flight.
2. A golf ball as defined in claim 1 wherein said surface depressions are dimples in the ball surface.
3. A golf ball as defined in claim 1 wherein said surface depressions are positioned in a circumferential 10 but those within the band are shaped to cause a greater air turbulence than those outside the band.