Patent Application
20150005116
Not Applicable.
Not Applicable.
Not Applicable
1. Field of the Invention
This invention relates to the field of sports. More specifically, the invention comprises an oblong throwing ball containing a large central passage that is bounded by a rigid material, with the outer portions of the ball being made of compressible foam.
2. Description of the Related Art
Spherical balls have been used in many sports and many amusement games. An example is the pressurized spherical ball used in the international game of football (known in America and some other regions as “soccer”). A spherical ball obviously rolls well and is easy to kick and otherwise manipulate with the feet. However, it is not easy to throw a large spherical ball.
The game of American football initially used a pressurized ball having an oblong shape. The original American football was similar in size and shape to the ball presently used in the sport of Rugby. However, as the forward pass evolved in American football during the first half of the 20th century, the ball began to change as well. The ball evolved to include distinct point at each end and a more slender shape. This allowed the ball to be more easily gripped and thrown.
The modern American football has a distinct central axis, with points at each end lying along this central axis. A skilled passer can release the ball so that (1) the ball's central axis is parallel to its flight path, and (2) the ball's center of rotation coincides with its central axis. When these two conditions exist, the passer has achieved a “tight spiral.” When the two conditions do not exist, the ball appears to “flutter.” This is true primarily because the leading point of the ball does not lie on the axis of rotation. Instead, it rotates around the axis of rotation, This eccentricity of rotation tends to persist throughout the flight of the ball. It significantly increases drag and also reduces directional stability. A badly eccentric throw is often called a “wounded duck.” For the same amount of initial velocity, it will not travel nearly as far as a “tight spiral.”
Thus, significant skill is required to correctly throw a modern American football. The exterior surface of such a football is also relatively rigid and requires a strong grip to throw effectively. It would be advantageous to provide a football having a more compressible exterior surface that could be more easily gripped. It would also be advantageous to provide a football having eccentricity-correcting features so that the ball would tend to stabilize in flight even when thrown poorly. The present invention provides these features as well as additional features.
The present invention comprises a throwable ball having a large internal passage aligned with its central axis. A relatively rigid insert defines the bounds of the internal passage. This insert is surrounded by compressible foam that gives the ball an easy gripping surface. Interlock features are preferably provided between the insert and the compressible foam so that they do not slip relative to each other.
The diameter of the internal passage is large in comparison to the overall diameter of the ball. The diameter of the internal passage is preferably at least 50% of the overall diameter. Although the insert extends for most of the length of the ball, it does not extend to the two ends. The ends only contain the compressible foam. This prevents injury or damage when the ball strikes something.
It is preferable to provide one or more interlocking features that will help lock the insert and the surrounding foam together. In the embodiment shown a pair of ribs 16 extend radially outward from the cylindrical wall. The foam is typically molded around the insert so the foam—while still in a non-set state—flows around the ribs. When the foam sets, the ribs create a mechanical interlock.
Foam body 28 includes a cylindrical foam body passage 54. Foam body passage 54 opens into a cylindrical insert recess 50. The insert recess is a cylindrical recess that does not extend for the entire length of the foam body. Instead, it stops at two insert containment steps 20. The first insert containment step abuts first insert end 40 and the second insert containment step abuts second insert end 42. These abutting relationships—along with the ribs on the insert—create a good mechanical interlock between the insert and the foam body.
Surface adhesion between the insert and the foam body may also assist in the creation of the desired interlock. This surface adhesion may be created by a variety of processes, including molding the foam over the insert or the use of a separate spray-on or liquid adhesive.
Exterior profile 38 has a maximum diameter in the center of the orb ball. This diameter tapers toward either end of the ball. The diameter of the internal passage remains constant (or nearly so). Foam body 28 extends to first end 34 and second end 36. However, in the embodiment shown, the elliptical exterior profile 38 does not extent all the way to the ends of the orb ball. Instead, a chamfer 44 is included proximate first end 34 and second end 36. In addition, a fillet 46 is used to join the extreme end of each chamfer to foam body passage 54.
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Those skilled in the art will understand the principles of angular momentum. In viewing
Looking back at
When the orb ball is thrown, air flows through its central passage with considerable velocity. The central passage acts like a wind sock, in that it will always tend to align itself with the prevailing flow. The prevailing flow is of course determined by the direction of the orb ball's flight. Thus, the flow through the central passage acts like a yaw damper for an imperfect throw. The term “imperfect throw” may apply to several conditions including: (1) The ball's axis of rotation is angularly offset from central axis 22, (2) The ball's central axis is misaligned with the direction of flight, and (3) combinations thereof.
For any of these conditions the flow of air through the orb ball's central passage will tend to damp the error. In other words, the flow through the central passage will tend to (1) Shift the ball's axis of rotation so that it lies on the central axis, and (2) Align the central axis with the direction of flight. These stabilizing forces tend to reduce drag and increase the range of a particular throw. A further drag reduction results from the fact that the central passage reduces the orb ball's projected frontal area.
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Foam body 28 may be created using an overmolding process. In overmolding, the completed insert is placed into a larger mold cavity. A liquid foam molding agent is then added to the cavity. The foam molding agent transitions to a solid while still in the mold. The unified assembly is then removed from the mold.
Insert 14 may be made of any desired thermoplastic. It could also be made using a thermoset material or a cross-linking material. For that matter, insert 14 could even be made of a metal such as aluminum.
Foam body 28 is preferably made from a high-density compressible foam. A suitable foam has a density in the range of 20 kilograms per cubic meter up to 60 kilograms per cubic meter. An even more preferable range lies between 30 kilograms per cubic meter and 50 kilograms per cubic meter. A foam's density is largely dependent upon the cell site in comparison to the cell wall thickness. A variety of techniques can be used to determine this value in order to bring the foam into the desired range of density. A wide variety of foams could be used. Examples include HDPE (high-density polyethylene) and polyurethane foams.
Overmolding tends to produce a good surface bond between the insert and the foam body. The assembly may be created in other ways, however. For example, the foam body could be separately molded and then connected to the insert. The foam body is quite pliable so the insert could be slipped into the interior and snapped into position. A separate adhesive could also be used to facilitate the surface bond.
Although the preceding description contains significant detail, it should not be construed as limiting the scope of the invention but rather as providing illustrations of the preferred embodiments of the invention. One skilled in the art may easily devise variations on the embodiments described. Thus, the scope of the invention should be fixed by the claims rather than the examples given.
