Tetherable game ball

A tetherable game ball is provided that includes a resilient spherical hollow ball (12) having an aperture (14) through which a knotted line (17) extends therethrough and forms a loop extending exteriorly of hollow ball (12) allowing a tether to be secured thereto. Aperture (14) is tapered inwardly and prevents a rigid force distributing plug (20) located within hollow ball (12) from being pulled through and out of aperture (14). The game ball can be constructed so as to have rebound and elastic properties similar to those of a racquetball.

TECHNICAL FIELD 
This invention relates to game balls, and more particularly to game balls 
that are securable to a tether. 
BACKGROUND ART 
In the past, many games have been developed that utilize a game ball that 
is tethered. These games often involve the use of paddles, bats, golf 
clubs or other implements that are used to strike the game ball. 
Substantial forces are exerted on the game ball when it is accelerated by 
the striking implement and substantial forces are also exerted upon the 
game ball when it encounters the resistance of the tether. Typical 
tetherable game balls are described and claimed in U.S. Pat. Nos. 660,787 
issued to Bissell on Oct. 30, 1900 entitled "Tether Ball"; 2,747,873 
issued to Carroad on May 29, 1956 entitled "Tethered Ball Game Apparatus" 
and 3,051,491 issued to Cabot on Aug. 28, 1962 and entitled "Returnable 
Practice Golf Ball". 
Such prior art tethered balls incorporate solid balls or have external 
attachments making them incompatible for certain types of games. In 
addition, such balls are subject to tearing and breaking away from the 
tether after extended use. 
A need has thus arisen for a tetherable game ball that is simple in 
construction, resists tearing and breaking away from the tether and has 
characteristics of an untethered ball. 
DISCLOSURE OF THE INVENTION 
In accordance with the present invention, a tetherable game ball is 
provided. 
In accordance with another aspect of the present invention, a tetherable 
game ball is provided that is hollow and the construction of the ball 
allows forces exerted between the ball and the tether to be distributed 
about a portion of the ball so that tearing of the ball associated with 
the tether is minimized. 
One embodiment of the tetherable game ball of the present invention 
comprises a resilient, spherical hollow ball having a single aperture 
therein. The aperture has an inward taper that begins at the exterior 
surface of the hollow ball and extends over at least a portion of the 
length of the aperture. A line of predetermined length having both ends 
passed through the aperture and secured together forms a loop that extends 
exteriorly of the aperture to allow a tether to be secured to the loop. A 
plug, having a hole therein, through which said loop is threaded, is 
located within the ball, between the aperture and the knot formed by the 
two ends of the line, which knot is larger than the hole in the plug 
adjacent the knot, so that forces exerted upon the line are distributed by 
the plug about the aperture and the line cannot be pulled from the ball. 
In accordance with a further aspect of the present invention, a hollow, 
tetherable game ball is provided in which a resilient, spherical hollow 
ball has two diametrically opposed apertures. Each of the apertures has an 
inward taper that begins at the exterior surface of the hollow ball and 
extends over at least a portion of the length of each of the two 
apertures. A line of predetermined length is passed through said apertures 
that is knotted at the ends, the knot being larger than the smallest 
diameter of the aperture and the knot being located within the hollow 
portion of the ball, the relative size of the aperture and the knot 
preventing the knot from being pulled outside of the ball. At each 
aperture, a boss forms an integral part of the ball. The boss is located 
interiorly of the ball with the apertures extending through the bosses, 
thereby reinforcing the ball and distributing forces exerted on the ball 
by the line in an area adjacent the apertures.

DETAILED DESCRIPTION 
FIG. 1 illustrates one preferred embodiment of the tetherable game ball 
according to the invention in which a side elevation view of single 
apertured tetherable game ball 10 is shown. Single apertured tetherable 
game ball 10 includes a resilient, spherical hollow ball 12 having 
aperture 14 therein having rebound characteristics similar to those of a 
racquetball. Preferably, aperture 14 is circular and tapered so that the 
diameter of aperture 14 decreases along at least a portion of the length 
of aperture 14 beginning at exterior surface 15 of hollow ball 12. In 
addition aperture 14 is preferable normal to exterior surface 15. 
The decreasing taper of aperture 14 is best illustrated in FIG. 2 which 
shows a cross-sectional view of a portion of single apertured tetherable 
game ball 10. According to the invention, and as illustrated in FIG. 2, 
aperture 14 may be beveled at interior surface 16 of hollow ball 12. A 
flexible line 17, of predetermined length, may be constructed of nylon or 
string and has both ends secured together to form knot 18 located within 
hollow ball 12 forming a loop which passes through aperture 14. In 
accordance with the invention, structure is provided to distribute forces 
exerted between hollow ball 12 and line 17 in the area adjacent aperture 
14 to provide for a more durable game ball. 
In this embodiment, the structure is force distributing plug 20, located 
within resilient spherical hollow ball 12. Plug 20 also prevents line 17 
from being pulled completely out of resilient spherical hollow ball 12 
when a force is exerted upon line 17 that may occur, for example, when 
ball 10 is struck by a racket or when a tether exerts a force on line 17. 
Force distributing plug 20, a separate structure from hollow ball 12, is 
preferably wedge shaped or cone shaped having a rounded point and a flat 
base, oriented such that the flat base is adjacent interior surface 16, as 
shown in FIG. 2. The diameter of aperture 14 at interior surface 16 is 
smaller than the base of force distributing plug 20. 
Plug 20 can be constructed of any rigid material, such as plastic or metal, 
and formed into the desired configuration by any method known to those 
skilled in the art, such as casting or injection molding. In assembling 
ball 10, both ends of line 17 can be threaded through hole 22 and then 
tied to form knot 18 while plug 20 is outside hollow ball 12, or the ends 
of line 17 can first be tied together to form knot 18 and then the loop 
formed can be inserted through hole 22. After assembly of plug 20 and line 
17, knot 18 and plug 20 are inserted through aperture 14 into the hollow 
portion of ball 12, knot 18 being inserted first and followed by the 
rounded end of plug 20. The elasticity of hollow ball 12 allows aperture 
14 to expand during insertion. Further, the wedge or cone shape of plug 20 
facilitates the expansion of aperture 14 thereby facilitating insertion. A 
thin, rigid rod or other suitable implement can be used to facilitate 
insertion of plug 20 and knot 18 into the hollow portion of ball 12. 
Hole 22 extends preferably through the longitudinal axis of force 
distributing plug 20, the diameter of hole 22 adjacent knot 18 being 
sufficiently smaller than the size of knot 18 so that knot 18 cannot pass 
through hole 22 when a force is exerted on line 17. When a force is 
exerted on line 17, plug 20 contacts resilient spherical hollow ball 12 
adjacent aperture 14. When this occurs, the force exerted on line 17 is 
distributed over the area of resilient spherical hollow ball 12 that plug 
20 contacts. Thus, reinforcing plug 20 distributes a force exerted upon 
line 17 over an area adjacent aperture 14 and prevents tearing of the wall 
of ball 10. 
FIG. 3 illustrates another preferred embodiment of a tetherable game ball 
according to the invention. FIG. 3 is a side elevational view of double 
apertured tetherable game ball 24 in which the side walls of hollow ball 
12 has therein apertures 26 and 28 which are diametrically opposed. Line 
30 extends through both apertures 26 and 28, the ends of line 30 being 
tied to form knot 32 that is located within hollow ball 12. Each of 
apertures 26 and 28 are inwardly tapered along at least a portion of the 
length of those apertures, the taper beginning at exterior surface 15. The 
inward taper of apertures 26 and 28 prevent knot 18 from being pulled from 
the hollow portion of resilient spherical hollow ball 12, thus enhancing 
the appearance of the game ball. 
Double apertured tetherable game ball 24 is assembled from hollow ball 12 
and line 30 by inserting one end of line 30 through apertures 26 and 28 so 
that both ends of line 30 extend exteriorly of hollow ball 12. A thin wire 
or a thin rigid rod, or any other suitable implement can be used to 
facilitate insertion of line 30 through apertures 26 and 28. The ends of 
line 30 are then tied together to form knot 32 which can then be either 
pushed or pulled through one of apertures 26 and 28 so that knot 32 is 
located within hollow ball 12. 
FIG. 4 is a side sectional elevational view of the double apertured 
tetherable game ball illustrated in FIG. 3. The force distribution 
structure shown in this embodiment consists of two bosses 34 and 36 which 
form an integral part of resilient spherical hollow ball 12. Bosses 34 and 
36 form interior surface 16 adjacent apertures 26 and 28, apertures 26 and 
28 extending through bosses 34 and 36, respectively. Bosses 34 and 36 
allow distribution of forces exerted on resilient spherical hollow ball 12 
by line 30 to prevent tearing of the game ball in the area adjacent 
apertures 26 and 28, making the game ball more durable. As shown in FIG. 
4, apertures 26 and 28 are identical, and may include a shallow bevel at 
interior surface 16 of hollow ball 12 around each of apertures 26 and 28. 
A tether is secured to line 30 by any suitable means, such as by tying a 
tether to line 30. The tether may be attached to a fixed location such as 
a base as shown in U.S. Pat. No. 2,747,873. 
According to the invention, the ball may be made of rubber or any resilient 
material. Perferably, the ball will be made from a cross-linked synthetic 
rubber compound so that when formed in a pressureless hollow ball, 
characteristics similar to that of a racquetball will result. 
Alternatively, larger or smaller balls can be constructed according to the 
invention. Lines 17 and 30 are preferably constructed of nylon cord. 
The design of the ball according to the invention provides a tetherable 
ball which is simple to construct in addition to being durable. Hollow 
ball 12 can be manufactured by any method or material known to those 
skilled in the art. For example, compression molding can be used to form a 
synthetic cross-linked rubber into a hollow ball having rebound and 
elastic characteristics similar to a racquetball and incorporating the 
formation of the aperture or apertures of the desired configuration. In 
both embodiments described herein, the apertures function as one-way 
valves for force distributing plug 20 in the embodiment shown in FIG. 1 
and for knot 32 in the embodiment shown in FIG. 3. Force distributing plug 
20 and knot 32 can be inserted through the aperture into the hollow 
portion of hollow ball 12, yet the aperture will restrain plug 20 or knot 
32 from being extracted therefrom. The elastic properties of hollow ball 
12 allow the aperture to stretch to permit the insertion of force 
distributing plug 20 or knot 32. The simplicity of construction allows 
line 30 to be easily replaced, should this become necessary. 
FIG. 5 is an illustration of the tetherable game ball being used in a game 
for which it is suitable. The tetherable game ball is secured to one end 
of an elastic tether, the other end of the tether being secured to a 
suitable base. As illustrated in FIG. 5, the game ball is being used as a 
racquetball trainer, without the necessity of having a walled court. The 
game ball of the invention can also be used to play racquetball without a 
walled court. When game ball 38 in FIG. 5 is struck by racket 40 of player 
42, ball 38 moves in the direction in which it is struck until the 
resistance of elastic tether 44 overcomes the momentum of ball 38 and 
accelerates ball 38 in a direction towards base 46 and player 42 allowing 
ball 38 to be struck again and thereby keep ball 38 in play. 
While this invention has been described in relation to its preferred 
embodiments, it is to be understood that various modifications thereof 
will now be apparent to one skilled in the art upon reading this 
specification and it is intended to cover such modifications as fall 
within the scope of the appended claims.