US 3810619 A
The system generally comprises a typical bowling ball having an elongate cavity extending inwardly generally radially a predetermined distance toward the center and a cap fitted at its outer end to restore the contour of the ball. The axis of the cavity usually extends at a substantial angle to the plane generally including the thumb and finger holes, and it may be left empty or filled with a weighting mass e.g. a barium compound, to vary the weight and performance characteristics of the ball. The cap is disc-like with a spherical outer surface to match the contour of the ball and has at least one recess in the marginal portion extending inward toward the axial center. The diameter of the disc is slightly more than that of the outer end of the cavity to produce an interference or force fit so that it cannot be removed without destroying it, thus preventing unauthorized weight changes from going unnoticed. To make an authorized change, a hole is drilled in the cap large enough to intersect the recess, leaving a ring which may be easily snapped out because of the great reduction in hoop compression force.
Description (OCR text may contain errors)
United States Patent [191 Taylor [451 May 14, 1974 BOWLING BALL AND METHOD OF CLOSING AND OPENING A CAVITY OPENING THEREIN  Inventor: Wilson G. Taylor, 2901 W. Valley,
Alhambra, Calif. 91803  Filed: Oct. 3, 1972  Appl. No.: 294,645
 U.S. Cl. 273/63 E, 29/525, 29/427,
215/51, 220/27, 273/63 B  Int. Cl A63b 37/00  Field of Search 273/63, 171, DlG. 20,58;
215/37 R, 55, 56, 51; 220/27, 42 B, 24 A, DIG. 19; 81/532; 29/525, 427
 References Cited UNITED STATES PATENTS 1,436,738 11/1922 Underhill 215/56 X 2,121,197 6/1938 .lackman.... 29/427 X 2,460,445 2/1949 Bigler v 273/170 2,607,956 8/1952 Brutus..... 273/171 3,441,274 4/1969 Collins 273/63 E 1,849,414 3/1932 Turnbull 273/63 E 2,198,981 4/1940 Sullivan 1 v 273/171 626,584 6/1899 Wilmerling 273/63 A FORElGN PATENTS OR APPLICATlONS 20.863 9/1911 Great Britain 273/63 E 346,671 4/1931 Great Britain 273/171 Primary Examiner-George J. Marlo Attorney, Agent, or Firm-Forrest .1. Lilly  ABSTRACT The system generally comprises a typical bowling ball having an elongate cavity extending inwardly generally radially a predetermined distance toward the center and a cap fitted at its outer end to restore the contour of the ball. The axis of the cavity usually extends at a substantial angle to the plane generally including the thumb and finger holes, and it may be left empty or filled with a weighting mass eg. a barium compound, to vary the weight and performance characteristics of the ball. The cap is disc-like with a spherical outer surface to match the contour of the ball and has at least one recess in the marginal portion extending inward toward the axial center. The diameter of the disc is slightly more than that of the outer end of the cavity to produce an interference or force fit so that it cannot be removed without destroying it, thus preventing unauthorized weight changes from going unnoticed. To make an authorized change, a hole is drilled in the cap large enough to intersect the recess, leaving a ring which may be easily snapped out because of the great reduction in hoop compression force.
7 Claims, 7 Drawing Figures BOWLING BALL AND METHOD OF CLOSING AND OPENING A CAVITY OPENING THEREIN BACKGROUND OF THE INVENTION This invention lies in the field of bowling balls and is directed to a novel system for modifying the weight and performance characteristics of such balls to compensate for varying conditions of play.
It has been known for some time that a bowling ball is a virtual gyroscope in action because it spins about an axis transverse to the general plane which includes the thumb and finger holes. The spin may be directly down the lane or at some angle to it depending on the manner of release. The spin rate does not normally correspond to the rate of forward motion at release and therefore the ball skids during the major portion of its travel and begins to roll shortly before it reaches the pins. Players have taken advantage of this fact by delivering the ball in such fashion that it will hook when the roll starts, and the ball will arrive at the head pin at an angle to the axis of the lane.
A system for enhancing the hooking action of the ball consists in forming a cavity in the ball at the side of the plane through the thumb and finger holes which corresponds to the direction of the desired hook and installing a weight in the cavity. The gravity moment of the weight during the skidding travel of the ball down the lane will cause a precession in the proper direction for the hook and, when the roll starts, the ball will travel at an angle toward the head pin. The mass of the weight and its moment arm determine the amount of precession. The same amount of weight is not suitable for all circumstances. Different lane conditions may require a different weight for the same bowler. Different bowlers deliver the ball differently and they need different weights. In some cases it is desirable to form a cavity and leave it empty to obtain the desired characteristics.
A cap over the cavity is needed both to retain the weight and to restore the contour of the ball. If the cap is permanently secured, as by cementing, it is not possible to change weights. If it is readily removable, then it is possible to remove it and make unauthorized weight changes without detection. Furthermore, it is possible for the cap to become loose during play and fall out with resulting loss of the weight.
SUMMARY OF THE INVENTION The present invention preserves the desirable benefits mentioned above while avoiding the disadvantages and provides a system which insures security of a weight in the ball, allows authorized changes to be made, and prevents unauthorized changes from being made without detection.
Generally stated. and in presently preferred form, the system involves forming a hole in the ball at the desired location and to the desired depth to define a cavity for reception of a weighting mass. The cavity may be formed by drilling. A mass of the desired weight is provided and has approximately the same dimensions as the cavity, the diameter of the mass being just enough less than that of the cavity for a sliding fit to facilitate removal while avoiding undesirable looseness.
A cap is provided to fill the outer portion of the cavity to hold the mass in place and also prevent its removal. The cap is disc-like and preferably cylindrical in outline, having a diameter several times as great as its thickness. The inner surface preferably lies generally in a plane while the outer surface is spherical to match the contour of the ball. The diameter of the cap is slightly greater than that of the outer portion of the cavity so that it will be an interference fit, and the cap is driven inward until it is flush with the surface of the ball. Since it is force-fitted and has nothing on its outer surface to grip and remove it, the cap cannot be non-destructively removed, thus preventing unauthorized weight changmg.
To make possible destructive but authorized removal, the marginal portion of the cap is provided with at least one recess extending generally radially inward from the edge a predetermined distance toward the axis of the cap. While the recess may take various forms, it is presently preferred to make it generally rectangular in cross section, stopping short of the outer surface but having a depth in the axial direction of more than half the thickness. The first step in removal is to drill an axially central hole through the cap of sufficient diameter to intersect the recess. This leaves an outer ring having a peripheral gap through most of its thickness which greatly reduces the hoop compression resistance of the ring and correspondingly reduces the binding engagement between the walls of the cap and the cavity. Removal is completed by inserting the tip of a removal tool in the pocket formed by the recess and the outer portion and snapping the ring out of position.
BRIEF DESCRIPTION OF THE DRAWINGS Various other advantages and features of novelty will become apparent as the description proceeds in conjunction with the accompanying drawings, in which:
FIG. 1 is a top plan view of a typical bowling ball having a side cavity to receive a weighting mass;
FIG. 2 is a schematic exploded view of the mass and cap about to be inserted in the cavity;
FIG. 3 is a schematic side view, partly in section of the mass and cap in place in the cavity;
FIG. 4 is a view similar to FIG. 3 with a modified cavity and mass;
FIG. 5 is a view similar to FIG. 3, showing the drilling operation;
FIG. 6 is a schematic perspective view of the remaining ring after the drilling operation; and
FIG. 7 is a view similar to FIG. 3, showing the removal operation.
DESCRIPTION OF PREFERRED EMBODIMENTS A typical bowling ball I0, illustrated in FIG. 1, is provided with a thumb hole 12 and finger holes 14, and the line 16 indicates the vertical central plane of the ball. A cavity 18 is formed in the ball by drilling. It extends generally radially inward at a substantial angle to the central plane to a predetermined distance to receive a weighting mass. It need not be exactly perpendicular to the plane, and also it need not be exactly radial although such attitude is preferred for simplicity.
In FIG. 2 it will be seen that a weighting mass 20 is aligned to enter cavity 18 and that a cap 22 is aligned to be fitted into the outer portion of the cavity. These components are shown mounted in place in FIG. 3. Although the American Bowling Congress permits the side weighting of bowling balls as illustrated, it does not allow the use of metal weights such as lead or iron. The mass used in the present invention comprises a capsule 24 having end caps 26 bonded to the capsule, the latter containing a finely divided material having a density Substantially greater than the density of the bowling ball material. A barium compound, preferably barium sulfate, is used and it is mixed with sufficient binder to render it a solid mass to prevent any of it from escaping from the capsule. A synthetic resin, such as epoxy resin, is used as the binder. The capsule enclosure prevents breaking or partial disintegration of the mass in handling and insures accuracy in sizing. The capsule, or its end caps if they extend radially outward, is made approximately .005 inch less than the diameter of the cavity for ready removalwhile avoiding undesirable looseness in place. It will be understood that the cross sec tion of the cavity and the capsule may be other than circular but they are preferably made circular for simplicity and ease of construction.
The cavity may be uniform from end to end but preferably the lateral dimension of the outer portion 28 is slightly larger than that of the main portion to define a shoulder 30 at a predetermined radial distance from the surface of the ball, the shoulder serving as a limiting stop for insertion of the cap.
The cap itself is an integral body and may have any parametric outline but preferably it is disc-like with a diameter several times as great as its thickness and with a cylindrical periphery or margin 32. It is formed of a suitable high impact plastic and its inner surface 34 may be flat or provided with various molding reliefs. In any event it lies generally in a plane. The outer surface 36 is spherical to match the contour of the ball. The diameter of the cap is about 0.015 inch greater than the diameter of the outer portion 28 of the cavity to produce an interference fit, and when it is driven into place it cannot be non-destructively removed. A tighter fit tends to split off portions of the ball and a looser fit does not provide adequate retention. Axially directed knurling 44 on margin 32 facilitates the force-fitting operation.
While the bottom, or inner end, 38 of the cavity may be flat in a plane transverse to the axis as shown in FIG. 3 when the cavity is formed by molding, it is more often conical as shown at 40 in FIG. 4 because the hole is usually drilled at a selected point after the ball is analyzed and the desired characteristics are determined. In this case, the cone at the inner end corresponds to the conical tip of the drill. Accordingly the capsule 24 is formed with one conical end 42 to match cone 40.
It will be apparent from the above that the cap cannot be removed without destroying it because it is force-fitted into place and there is nothing on its outer surface which can be gripped to pull it out. It will not come out inadvertently because of its tight fit. An unauthorized removal for a weight change is readily detectable. Authorized removal is made possible by the special formation provided in the marginal portion of the cap to reduce the binding engagement between the walls of the cap and the outer portion of the cavity in response to removal of the axially central portion of the This formation comprises a recess 46 formed in the marginal portion 32 of the cap. The recess extends generally radially inward from margin 32 toward the axis of the cap for a predetermined distance, and from the inner surface to a point short of the outer surface. The
radial extent of the recess is preferably from about 15 7 percent to about 25 percent of the diameter and its depth in the axial direction from the inner surface is about percent to percent of the thickness of the cap. The cross section of the recess may take any suitable form but is preferably rectangular.
The removal operation is illustrated in FIGS. 5 to 7. A cylindrical core drill 48 is operated to cut out the axially central part of the cap and is of such size that the hole which it forms will intersect the inner portion of recess 46. The result is the ring shown in FIG. 6, and the recess or its remainder, now defines a parametric or circumferential gap which greatly reduces the hoop compression resistance of the ring, and thus its resistance to removal. As shown in FIG. 7, it is now a simple matter to insert the tip of a removal tool 50. such as a screw driver or a hook, in the pocket 46 and snap the ring out of the cavity. The availability of the pocket avoids the danger of damage to the ball or the capsule which might result from random prying actions.
As previously stated, shoulder 30 serves as a depth limiting stop. Its depth is the same as the height of margin 32 so that when the cap bottoms on the shoulder it will be flush with the surface of the ball. In addition, the length of capsule 24 accurately matches the depth of cavity 18, so that the cap contacts the capsule and prevents any movement radially of the ball.
In many cases it is desirable to modify a ball by reducing rather than increasing weight at a selected spot. In such case, a cavity 18 is drilled in the ball and left empty. Shoulder 30 then has special utility since it prevents any possibility of forcing cap 22 inward to a depth below its flush position, which could not occur in any event when a capsule is present in the cavity.
1. A bowling ball comprising: a spherical ball formed with an elongate weight receiving cavity extending generally radially inward from its spherical external surface to a predetermined depth less than the radius of the ball; and
a disk-like cap having a smooth outer surface closing the outer end of said cavity and secured with a friction tight fit in the outer end of the cavity with its inner surface adapted to engage a weight mass in the cavity, and its outer surface spherical and flush with the surface of the ball to maintain its normal contour, a marginal portion of the cap having a recess sunk radially inwardly to a predetermined depth therein, in back of the spherical outer surface of the cap, so that it can subsequently be intersected by a large bore drilled generally axially through the cap to form a readily removable ring, with a remainder of said recess therein to reduce hoop compression and thereby enable easy removal.
2. A ball as claimed in claim 1 including a weight mass in the form of a capsule containing finely divided material having a substantially higher density than the density of the material of the ball.
3. A ball as claimed in claim 2; wherein the high density material is a barium compound.
4. A ball as claimed in claim 2; wherein the high density material is barium sulfate mixed with a binder in sufficient quantity to form a solid mass.
5. A ball as claimed in claim 4; wherein the binder is a synthetic resin.
6. A ball as claimed in claim 1; wherein the cavity has a conical inner end converging toward the center ofthe ball;
6 mined depth, comprising:
force-fitting into the outer end of the cavity a disclike cap having a recess in its marginal portion extending inward a predetermined distance toward its axial center to close the cavity and restore the contour of the ball;
drilling a hole through the cap to intersect the inner portion of the recess and produce a ring having a recess therein which reduces the hoop compression resistance thereof; and
snapping the ring out of the cavity.