Abstract:
A system and method for producing a bowling ball, where the thumb hole and finger holes in the bowling ball are angled to accurately match the anatomical requirements of the bowler&#39;s hand. The system includes a measuring jig assembly for obtaining data on where to drill finger holes in a bowling ball. The measuring jig assembly has holes for the thumb, the middle finger and the ring finger. The position of the thumb hole can be moved in a unique manner so that the thumb hole need not be located below the middle finger hole and the ring finger hole. Furthermore, the angle at which each of the holes enters the measuring jig assembly is adjustable across a range of motion that mimics that achievable by the tips of the thumb, middle finger and ring finger of a bowler. Accordingly, the holes can be adjusted to unique angles required by a particular bowler&#39;s hand anatomy. The data retrieved from the measuring jig assembly is then used to produce a bowling ball customized to a bowler&#39;s hand.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     In general, the present invention relates to devices and methods of fitting and drilling finger holes in a bowling ball. More particularly, the present invention relates to bowling ball fitting devices that enable the holes for the thumb to be drilled in numerous different orientations with respect to the holes for the middle and ring fingers. 
     2. Description of the Prior Art 
     A regulation bowling ball contains three finger holes. Typically, a bowler grasps the holes in the bowling ball with his/her middle finger, ring finger and thumb. However, every person has a uniquely shaped hand and fingers. Furthermore, every bowler has their own unique bowling style that is affected by the position of their fingers as they grasp and roll the bowling ball. It is for this reason that bowling balls are not manufactured with holes. Rather, bowling balls are manufactured as solid spheres. The finger holes are drilled into a bowling ball in a secondary procedure at the time of purchase of the bowling ball. 
     To drill a hole in a bowling ball, the purchaser of the bowling ball is first fitted. In the fitting procedure, a person&#39;s hand is placed within a fitting jig. The fitting jig contains adjustable finger holes so that a person can customize the position of the finger holes to their needs. Once a person is comfortable with the holes on the bowling ball, the settings measured from the fitting jig can be transferred to a drilling machine and the desired finger holes can be reproduced in an actual bowling ball. 
     In many prior art fitting jigs, the degree of adjustability is limited. Many traditional fitting jigs contain only adjustments for the middle finger and the ring finger. The position of the thumb hole is static. Such prior art devices are exemplified by U.S. Pat. No. 5,601,385 to Towers, entitled, Apparatus For Fitting and Drilling Bowling Balls. 
     The static position of thumb holes in many prior art fitting jigs is insufficient for many bowlers. Certain bowlers require and/or desire finger hole configurations where the position of the thumb hole can also be varied. Accordingly, in the prior art, some fitting jigs have been developed where the position of the thumb hole can be altered. Such prior art fitting jigs are exemplified by U.S. Pat. No. 4,067,110 to Amelio, entitled Thumb Finger Hole Positioning Device For Bowling Balls. 
     Although fitting jigs, such as is shown in the Amelio patent, are better than prior art static thumb hole fitting jigs, such fitting jigs still are not sufficient for many bowlers. In the Amelio patent, the thumb hole jig cannot be adjusted along the curved surface of the bowling ball. Rather, the thumb jig can only be adjusted along a linear path. Furthermore, the thumb hole jigs adjust about a pivot point that is deep within the bowling ball fitting jig. However, a thumb enters a bowling ball from the surface of the bowling ball, and pivots near the surface of the bowling ball. Do to the different points of pivotal rotation, the angles achievable by a person&#39;s thumb cannot be accurately matched by the thumb hole jig. 
     Prior art fitting jigs for bowling balls therefore are still not capable of accurately fitting a bowler&#39;s fingers with anatomically correct precision. Rather, prior art fitting jigs still require compromises in finger position which may cause discomfort and/or inaccuracy to the bowler. 
     A need therefore exists for an improved fitting jig for a bowling ball that can provide a wide variety of finger and thumb positional adjustments in an anatomically correct manner. This need is met by the present invention system and method as described and claimed below. 
     SUMMARY OF THE INVENTION 
     The present invention is a system and method for producing a bowling ball, where the thumb hole and finger holes in the bowling ball are angled to accurately match the anatomical requirements of the bowler&#39;s hand. The system includes a measuring jig assembly for obtaining data on where to drill finger holes in a bowling ball. The measuring jig assembly has holes for the thumb, the middle finger and the ring finger. The position of the thumb hole can be moved in a unique manner so that the thumb hole need not be located below the middle finger hole and the ring finger hole. Furthermore, the angle at which each of the holes enters the measuring jig assembly is adjustable across a range of motion that mimics that achievable by the tips of the thumb, middle finger and ring finger. Accordingly, the holes can be adjusted to unique angles required by a particular bowler&#39;s hand anatomy. The data retrieved from the measuring jig assembly is then used to produce a bowling ball customized to a bowler&#39;s hand. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a better understanding of the present invention, reference is made to the following description of exemplary embodiments thereof, considered in conjunction with the accompanying drawings, in which: 
     FIG. 1 is a front view of an exemplary embodiment of a bowling ball finger hole fitting jig in accordance with the present invention; 
     FIG. 2 is cross-sectional view of the thumb hole assembly from the embodiment shown in FIG. 1; 
     FIG. 3 is a fragmented top view of the thumb hole assembly shown in FIG. 2; 
     FIG. 4 is a cross-sectional view of an alternate embodiment of a thumb hole assembly; 
     FIG. 5 is a schematic view of a finger/thumb hole assembly showing range of movement; and 
     FIG. 6 shows a bowling ball in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, an exemplary embodiment of a bowling ball fitting jig  10  is shown. The bowling ball fitting jig  10  has a spherical housing  12  that is the same overall shape as a bowling ball. The spherical housing  12  is divided into two separate hemispheres  16 ,  18  that align along a common equatorial joint  14 . Internally within the housing  12 , the two hemispheres  16 ,  18  are joined together along a common axis  20  that runs perpendicular to the plane of the equatorial joint  14 . Each hemisphere  16 ,  18  is capable of independently rotating around the common axis  20 . Accordingly, the rotational position between the two hemispheres  16 ,  18  can be altered as desired. 
     On the lower hemisphere  18  is located a thumb hole assembly  22 . The thumb hole assembly  22  contains a cylindrical structure having an open end on the curved surface of the lower hemisphere  18 . Adjustment knobs  24 ,  26  are also disposed on the lower hemisphere  18 . The adjustment knobs  24 ,  26  are used to adjust the orientation of the thumb hole assembly  22 , as will later be explained. 
     Two finger hole assemblies  28 ,  30  are located on the upper hemisphere  16  of the spherical housing  12 . The finger hole assemblies  28 ,  30  are used to position the ring finger and the middle finger of the bowler being fitted. Adjustment knobs  32 ,  34  are located on the upper hemisphere  16 . The adjustment knobs  32 ,  34  are used to adjust the orientation of the finger hole assemblies  28 ,  30 , as will also be later explained. 
     Gauge markings  33  are located on at least one side of the equatorial joint  14  between the upper hemisphere  16  and the lower hemisphere  18  of the spherical housing  12 . A position icon  35  is opposed to the gauge markings  32  on the opposite hemisphere. As the lower hemisphere  18  and the upper hemisphere  16  are rotated relative to each other, about the central axis  20 , the degree of rotation between the two hemispheres  16 ,  18  can be quantified by the location of the position icon  35  relative the gauge markings  33 . 
     As the two hemispheres  16 ,  18  are rotated relative to each other, the relative positions of the finger hole assemblies  28 ,  30  and the thumb hole assembly  22  change. However, regardless of the change in position, the thumb hole assembly  22  remains on the curved exterior of the spherical housing  12 . 
     Referring to FIG. 2, a first embodiment of the workings of the thumb hole assembly  22  is shown. The thumb hole assembly  22  includes a cylindrical tube  40  that extends into the spherical housing  12 . The cylindrical tube  40  has an open top end  42 . An annular thumb insert  44  is placed within the cylindrical tube  40  through its open top end  42 . When fitting a bowler, an annular thumb insert  44  of the proper size is selected and inserted into the cylindrical tube  40 , prior to the positional adjustments of the thumb hole assembly  22 . The annular thumb insert  44  is retained in the cylindrical tube  40  by a spring biased locking ball  46 , which engages a corresponding groove  47  on the exterior of the annular thumb insert  44 . 
     Referring to FIG. 3, in conjunction with FIG. 2, it can be seen that the cylindrical tube  40  is supported by a gimbal system. The gimbal system includes a yoke  48 . The yoke  48  is a U-shaped element that extends around the cylindrical tube. Pivot arms  50  radially extend from opposite sides of the cylindrical tube  40 . The pivot arms  50  engage the yoke  48  in a manner that enables the pivot arms  50  to rotate freely within the yoke  48 . Accordingly, the pivot arms  50  act as an axle, wherein the cylindrical tube  40  is free to swing about that axle. 
     The yoke  48  of the gimbal system is supported by a bracket element  52 . The bracket element  52  is pivotably connected to the spherical housing  12 , via a pivot pin  54 . Accordingly, the bracket element  52  and the yoke  48  it supports can rotate freely about the pivot pin  54 . 
     Looking now solely at FIG. 2, it can be seen that when a bowler has his/her hand fitted, that bowler places his/her thumb into the thumb hole assembly  22 . As a person&#39;s thumb enters the thumb hole assembly  22 , the thumb bends at the joint between the middle and distal phalange of the thumb. As such, the thumb, pivots about that joint within the thumb hole assembly  22 . Typically, when bowling, a bowler will place their thumb in a bowling ball to a point where the thumb joint between the middle and distal phalange is slightly below the exterior surface of the bowling ball. The pivot arms  50  that extend from the cylindrical tube  40  are positioned to correspond to the joint of the thumb, when the thumb is placed into the thumb hole assembly  22 . Accordingly, the cylindrical tube  40  is free to pivot at approximately the same position as is the bowler&#39;s thumb. The cylindrical tube  40  can therefore pivot with the thumb in an anatomically correct manner. 
     If a person&#39;s thumb move sideways, outside the range of motion provided by the pivot arms  50 , then the entire yoke  48  moves about the pivot pin  54 . Thus, referring to FIG. 2, it can be seen that the gimbals system enables the cylindrical tube to rotate about the pivot arms  50  in the plane of the paper. The gimbals system also enables the cylindrical tube  40  to rotate about the pivot pin  54  in a plane perpendicular to the plane of the paper. The combined freedom of movement enables the cylindrical tube  40  to align with the natural anatomically correct position of the bowler&#39;s thumb. 
     Movement of the cylindrical tube  40  is controlled by adjustment knobs. In FIG. 2, it can be seen that a first adjustment knob  26  is attached to a threaded shaft  56 . The threaded shaft  56  engages an internally threaded shaft  58 . The internally threaded shaft  58  engages the cylindrical tube  40 , via a universal joint  60 , such as a ball and socket joint. A guide pin  62  extends downwardly from the universal joint  60 . The guide pin  62  rides in a slot of a guide bracket  64 . The guide bracket  64  is rigidly affixed to the cylindrical tube  40 . As the first adjustment knob  26  is turned, the bottom of the cylindrical tube  40  is rotated about the pivot arms  50 . The presence of the guide pin  62  in the guide bracket  64  ensures that the force applied by the first adjustment knob  26  acts in the proper direction on the cylindrical tube  40 . 
     The first adjustment knob  26  is calibrated. As such, the effect of the first adjustment knob  26  on the cylindrical tube  40  is known for any rotational position of the first adjustment knob  26 . Once the cylindrical tube  40  is adjusted to a proper position for a particular bowler, the reading from the first adjustment knob  26  can be recorded and entered into a bowling ball drilling machine. 
     Referring to FIG. 3, it can be seen that a second adjustment knob  24  also engages the cylindrical tube  40 . The second adjustment knob  24  is attached to an externally threaded shaft  70 . The externally threaded shaft  70  engages an internally threaded shaft  72 , wherein the rotation of the adjustment knob  24  makes the combined length of the externally threaded shaft  70  and the internally threaded shaft  72  either longer or shorter. The internally threaded shaft  72  engages the cylindrical tube  40 , via a universal joint, such as a ball and socket joint, as was previously described. The movement of the universal joint (not shown) is guided by the presence of a guide pin (not shown) in a slot of a guide bracket  64 . This operation was also previously described. 
     As the second adjustment knob  24  is turned, the cylindrical tube  40  and the yoke  48  that supports the cylindrical tube  40  are rotated about pivot pin  54 . The second adjustment knob  24  is calibrated. As such, the effect of the second adjustment knob  24  on the cylindrical tube  40  is known for any rotational position of the second adjustment knob  24 . Once the cylindrical tube  40  is adjusted to a proper position for a particular bowler, the reading from the second adjustment knob  24  can also be recorded and entered into a bowling ball drilling machine. 
     Referring now to FIG. 4, an alternate embodiment of a thumb hole assembly  80  is disclosed. In this embodiment, the previously described tubular shaft is replaced with a jig element  82  that has a cylindrical lower section  84  and a spherical upper section  86 . A tubular shaft  88  extends down the center of the jig element  82 . A socket relief is formed in the spherical housing  90 . An annular collar  92  engages the spherical housing  90  above the jig element  82 , thereby locking the spherical upper section  86  of the jig element  82  in an enclosed socket cavity. The spherical upper section  86  of the jig element  82  is free to move within the enclosed socket cavity. Accordingly, the jig element  82  acts as the ball in a ball-and-socket joint. 
     The rotational movement of the jig element  82  is centered around a center of rotation C. The center of rotation C is positioned at the same depth as the pivot arms  50  in the embodiment of FIG.  2 . Accordingly, when a person places their thumb in the thumb hole assembly  80 , the joint of the thumb lays near the center of rotation C. 
     The tubular shaft  88  that extends down the center of the jig element retains an annular thumb insert  94  in the same manner as was previously described with regard to the embodiment shown in FIG.  2  and FIG.  3 . Adjustments to the position of the jig element  82  are also made using the same adjustment knob subassemblies that were previously described with regard to the embodiment shown in FIG.  2  and FIG.  3 . 
     Referring to FIG. 5, it will be understood that embodiments of the thumb hole assemblies previously described are merely exemplary. The thumb hole assembly, in accordance with the present invention, can have any configuration that enables the thumb hole assembly to have the range of movement shown in FIG.  5 . The embodiments of the thumb hole assembly previously described show possible configurations for allowing the range of movement shown in FIG.  5 . 
     In FIG. 5, a schematic of a thumb hole structure  100  is shown. The thumb hole structure  100  is centered around a central axis  102 . On the central axis  102  is a fixed pivot point P. The pivot point P is a predetermined distance D below the exterior surface of the spherical housing  104 . The predetermined distance is preferably between ⅛ inch and 1 inch so as to correspond with the anatomical position of the joint on the thumb. The thumb hole structure  100  can be mounted within the spherical housing  104  in any manner that enables the central axis  102  of the thumb hole structure to freely move about the pivot point P within the shown conical range R, wherein the pivot point P is at the apex of the conical range R. 
     Until this point in the description, all means for adjustment have been applied to the thumb hole of the bowling ball fitting jig. As has been previously stated, the bowling ball fitting jig also has fitting holes for a bowlers ring finger and middle finger. The fitting holes for the ring finger and middle finger can be traditional fitting holes used in the prior art. However, it is preferred that the same range of motion provided to the thumb hole be adapted for use with the ring finger and middle finger holes. Accordingly, the range of movement and adjustments previously described for the thumb fitting hole can also be applied to the finger fitting holes. Accordingly, the range of motion shown in FIG. 5 can also be obtained at both the finger fitting hole for the ring finger and the finger fitting hole for the middle finger. 
     Returning to FIG. 1, it will now be understood that to use the bowling ball fitting jig  10 , a person adjusts the distance between the thumb hole assembly  22 , the middle finger assembly  28  and the ring finger assembly  30  to the requirements of the bowler&#39;s hand. As part of the adjustment, the thumb hole assembly  22  can be rotated out of alignment with the finger hole assemblies  28 ,  30  by rotating the lower hemisphere  18  of the spherical housing  12  in relation to the upper hemisphere  16  of the spherical housing  12 . 
     After the desired offset of the thumb hole assembly  22  is obtained and the general distance between the thumb hole assembly  22  and finger hole assemblies  28 ,  30  is achieved, a bowler places his/her thumb into the thumb hole assembly  22  and places his/her fingers into the finger hole assemblies  28 ,  30 . Once the thumb is in the thumb hole assembly  22 , the orientation of the thumb hole assembly  22  is adjusted to match the anatomically correct orientation of the bowler&#39;s thumb. Consequently, the thumb lies naturally in the thumb hole assembly  22 . Once the thumb hole assembly  22  is adjusted appropriately, the readings from the adjustment knobs  24 ,  26  of the thumb hole assembly are recorded for later use in a bowling ball drilling machine. 
     The process for fitting a bowler&#39;s fingers into the finger hole assemblies  28 ,  30  is the same as the process just described for fitting the thumb. The middle finger and ring finger are placed within the finger hole assembles  28 ,  30 . After the finger hole assemblies  28 ,  30  are adjusted for distance, as is traditional, the orientation of the finger hole assemblies  28 ,  30  is then adjusted to match the anatomically correct orientation of the bowler&#39;s fingers. Consequently, the tip of the middle finger and ring finger lay naturally in the finger hole assemblies  28 ,  30 . Once the finger hole assemblies  28 ,  30  are adjusted appropriately, the readings from the adjustment knobs  32 ,  34  of the finger hole assemblies  28 ,  30  are recorded for later use in a bowling ball drilling machine. 
     Referring to FIG. 6, there is shown a bowling ball  110  that has been drilled using data obtained from the bowling ball fitting jig previously described. The bowling ball  110  includes a thumb hole  112 , a middle finger hole  114  and a ring finger hole  116 . The thumb hole, middle finger hole and ring finger hole each has their own unique central axis  113 ,  115 ,  117 , respectively. The central axis for the different holes need not be in line with the geometric center of the bowling ball. Furthermore, the central axis for the different holes need not have any orientational correspondence to one another. Rather, the various holes can progress in any direction within the bowling ball  110 , provided the direction selected corresponds with the natural anatomical orientation of the bowler&#39;s fingers. 
     The combination of a thumb hole in a bowling ball that is not aligned under the finger holes along with holes that are aligned anatomically correctly forms a grip, herein referred to as the Max-Y Grip. 
     It will be understood that the embodiments of the present invention described and illustrated herein are merely exemplary and a person skilled in the art can make many variations to the embodiments shown without departing from the scope of the present invention. All such variations, modifications and alternate embodiments are intended to be included within the scope of the present invention as defined by the appended claims.