US 3865369 A
A bowling ball is top-weighted to offset the loss of weight resulting from drilling of finger holes and to provide a small additional top weight to improve performance of the ball, by means of a weighted insert located near to and on the top side of the midplane, and with a substantial part of the added weight located near the surface of the ball to increase the rotational inertia of the ball.
Claims available in
Description (OCR text may contain errors)
United States Patent 1191 Randolph [451 Feb. 11, 1975 BOWLING BALL  Inventor: John L. Randolph, 1076 N. Jacoby Rd., Akron, Ohio 44321  Filed: Dec. 20, 1973 21 Appl. No.: 426,506
 US. Cl 273/63 E  Int. Cl A63b 37/10  Field of Search 273/58, 63, 64
 References Cited UNITED STATES PATENTS 2,035,975 3/1936 Meyer 273/63 E 2,291,738 8/1942 Luth et a1. 273/63 E 3,270,108 8/1966 Randolph 273/63 G X Fabanich 273/63 E Skuse 273/63 E Primary Examiner-George J. Marlo Attorney, Agent, or Firm-Harold S. Meyer  ABSTRACT A bowling ball is top-weighted to offset the loss of weight resulting from drilling of finger holes and to provide a small additional top weight to improve performance of the ball, by means of a weighted insert located near to and on the top side of the midplane, and with a substantial part of the added weight located near the surface of the ball to increase the rotational inertia of the ball.
9 Claims, 6 Drawing Figures ANNULAR WEIGHT BOWLING BALL BACKGROUND It has been the practice for many years to incorporate unsymmetrical weights in bowling balls in one way or another to offset the loss of material and therefore of weight resulting from drilling of finger holes. Such weights are preferably on the same side of the ball as the finger hole location, to avoid excessive unbalance, but are often purposely made heavier than the drillings so as to provide unbalance in a predetermined location with respect to the finger holes or grip, to facilitate rolling of the ball in a curved path, when that is desired.
Thus the Luth et al., .U.S. Pat. No. 2,291,738 shows various ways to provide a dense material on one side of the ball, into which finger holes are drilled, and a lighter density material located predominantly on the other side of the ball for approximate balance after the finger holes are drilled, with the dense material located either THE DRAWINGS In the accompanying drawings,
FIG. 1 represents a bowling ball made in accordance with this invention partly broken away to show in section the internal construction.
FIG. 2 similarly shows a slightly different construction made up of two, rather than three, components.
FIG. 3 similarly shows a construction like that of FIG.
on 0 MM. that tha umtnmpd insert is annular.
balloons are tiny hollow spheres of synthetic resin material which, when mixed into a composition such as the casting resins used in making bowling balls, provide hollow spaces and therefore lighten the material used.
In the manufacture of such a ball, spherical sheet metal molds may be used, divided at an equatorial plane, such as the molds indicated diagramatically in FIG. 5 and FIG. 6. The bottom half 30 of such a mold will be a hemisphere with a flanged margin and can be used in making both the weighted segment 12 and surrounding spherical core 11. This part of the ball can be made from any material which can be handled satisfactorily in making a fairly massive shaped article, but preferably is made from a casting resin such as one of the modern epoxy or polyester resins, preferably a slightly resilient polyester which is supplied as a liquid and which sets up spontaneously when mixed with a very small portion of a suitable peroxide. Such epoxy and polyester materials are well known in the bowling ball business and are described in detail in prior publications, such as Satchell U.S. Pat. No. 3,068,007 and Baggcnstoss U.S. Pat. No. 3,256,018.
A suitable composition may contain 8 lbs. of liquid polyester resin and 13 lbs. of ground barytes intimately mixed together and then further mixed with a suitable small proportion of a peroxide catalyst such as methyl ethyl ketone peroxide or di tertiary-butyl peroxide, or a mixture of them, preferably with an activator such as cobalt naphthenate. Since the casting is rather massive, care must be taken to use a minimumm quantity of catalyst which will assure proper hardening, else the material may set up too quickly and overheat, as is well known.
The exact quantity of the weighted liquid synthetic resin used will depend upon the densities of the other components of the finished ball and the relative volumes occupied by each and, of course, on the exact magnitude of off center weight, or top weighting, which is desired. This can be calculated but is also easily determined by a few preliminary trials. It is generally satisfactory to use a quantity of the weighted liquid resin which will about half fill one of the hemispherical half molds 30, with more or less weighting material depending on the weight of ball being made and the density of the other components of the ball. When the resin has set up to constitute the weighted internal portion 12, it is removed from the mold 30 and a hole is drilled in the exact center of the spherical surface to receive a supporting pin. The supporting pin 31 is then affixed to the center of the bottom mold half 30, and the hardened weighted spherical segment 12 is set on the pin, with its plane surface in the same equatorial plane as the top of the hemispherical mold half 30. The top half mold 32 is then fastened to the bottom half 30, and the mold is filled, through the filler neck 33, with the lighter resin composition making up the core portion 11, as is shown in FIG. 6. The core material 11 may be made of exactly the same liquid polyester resin as the weighted segment 12, except that it may contain a mediumor lightweight filler as already described. Such composition containing the necessary catalyst will surround and embed the weighted portion 12 and form a complete sphere with the weighted portion 12 having its plane surface, which was the free surface when the weighted material was cast, being at such a level as to lie-in the exact midplane of the mold andtherefore of the spherical core.
When the material 11 is set up, the mold halves 30 and 32 are separated and the spherical core is removed and is finished by grinding off the projecting stub of material formed by the filler neck 33 of the mold. The entire surface may be ground to assure that the core is perfectly spherical so that it can be exactly concentric with the surface of the finished ball.
The spherical core 11 is then placed in another spherical mold which can be exactly like the one already used except that it is a fraction of an inch to an inch or more larger in diameter. The bottom half 30 of the larger mold will also contain a supporting pin 31 on which the hardened core 11 can be mounted concentric with the inner surface of the mold.
The surfacing composition 10 is then prepared either from the same basic material as the one used in making the core or from one which is more or less different in composition and properties, as being, for example, softer and more resilient, or as being more attractive in appearance when finished to the desired exact dimensions. Thus the core ll may be made from a resin composition sclected to have a finished hardness of 80 on the Shore D Durometer, while the surface layer 10 may be made from a grade or resin selected to set up to a more resilient consistency, such as Durometer or even less.
When the surfacing resin has hardened, the mold is opened again, the ball is removed, and the mold flash and projecting stub from the filler neck are ground off. The hole previously occupied by the supporting pin 31 may then be drilled out clean, and in any event is filled with a small quantity of the same surfacing composition or one which is made different in appearance as by adding or omitting coloring material so as to identify the axis on which the weighted segment 12 is located.
When the material used to fill the hole is hardened, the ball is ground to the exact desired size and perfect sphericity and is then finished ready for sale. If the top of the ball is not indicated by a plug of visibly different material, as described above, the location of the weight axis, for proper positioning of the finger holes can be determined easily by supporting the ball for free rotation, as on a cushion of air, so that it will take a position with the heavy top side down.
It is not essential that the balls of this invention have the weighted portion 12 embedded in a spherical core ll which is later surrounded by a surface layer 10. Instead, a single composition can be used for the entire volume surrounding the weighted insert 12, as shown in FIG. 2.
In this embodiment, the weighted insert 12 is placed directly in a spherical mold of a proper size for casting the final ball, and all of the ball other than the weighted insert 12 is cast from a single composition as shown in FIG. 2.
It is also not essential that the weighted insert be the exact shape of a spherical segment. For example, there are some additional advantages in making it annular, so that more of the weight will be close to the surface of the ball. Such an annular insert 15, as shown in FIG. 3, can be made very simply in the same spherical half mold 30 shown in FIG. 5 by setting a cylinder in the mold to serve as a mold core, and then casting the weighting composition in the mold 30 around the cylinder.
If it is desired to provide an annular weighted insert which is smoothly rounded, it can be made toroidal or doughnut shape, as indicated in FIG. 4, showing a ball containing an off-center toroidal weight 20.
In every case the weighted insert, regardless of its shape, should be close to the midplane, with its bottom surface close to and preferably coinciding with the midplane of the finished ball, and its opposite surface substantially spaced from the top of the ball. The margins of the weighted insert, though, should be near enough to the surface to produce a significant increase in rotational inertia around the diametral axis passing through the top where the finger holes will be located.
1. An integral solid bowling ball containing a top weight which more or less offsets the one-sided loss in weight resulting from drilling of finger holes in the neighborhood of an axis passing through the center of the ball and the center of mass of the weight, characterized in that the weight is spaced from the surface with the spacing greater along the axis than in a circumferential location near the midplane, that the weight is closely adjacent to and generally on the top side of the midplane, and that the weight has its mass s distributed that a substantial part of its mass is closer to the surface than to the center of the ball.
2. A bowling ball as in claim 1, in which the weight is entirely on one side of the midplane.
3. A bowling ball as in claim 2, in which the lower surface of the weight is at the midplane.
4. A bowling ball as in claim 1, in which the weight is a segment of a sphere with the plane surface of the segment toward the midplane and the curved surface of the segment toward the top of the ball.
5. A bowling ball as in claim 4, in which the plane surface of the weighted segment of a sphere is in the midplane of the ball.
6. A bowling ball as in claim 5, in which a marker for location of finger holes is at the top end of the axis.
7. A bowling ball as in claim 1 in which the weight is annular.
8. A bowling ball as in claim 7 in which the weight is toroidal.
9. A bowling ball as in claim 1, in which a marker for location of finger holes is at the top end of the axis.