Avoidance of resonance in the inflatable sport ball by limiting the critical ratio

Abstract

A sport ball having an internal device such as an internal pump has a critical ratio that insures that rebound characteristics or coefficient of restitution of the ball, such as a basketball, will be acceptable for use. The invention also includes the method for evaluating design and/or quality control of a sport ball by measuring the internal vibration and determining the critical ratio of the sport ball.

What is claimed:  
     
         1 . A sport ball comprising a self-contained inflation mechanism, wherein said sport ball comprising a self-contained inflation mechanism has substantially the same rebound characteristics as a corresponding sport ball that does not comprise a self-contained inflation mechanism.  
     
     
         2 . The sport ball of    claim 1   , wherein the sport ball is hollow.  
     
     
         3 . The sport ball of    claim 1   , wherein the sport ball is a basketball.  
     
     
         4 . The sport ball of    claim 3   , wherein the basketball is a regulation size basketball.  
     
     
         5 . The sport ball of    claim 3   , wherein the basketball is a non-regulation size basketball.  
     
     
         6 . The sport ball of    claim 1   , wherein the basketball is a youth size basketball.  
     
     
         7 . The sport ball of    claim 1   , wherein the sport ball is a soccer ball.  
     
     
         8 . The sport ball of    claim 1   , wherein the sport ball comprises a cover wherein the material is selected from the group consisting of leather, synthetic leather, composites, rubber materials and combinations thereof.  
     
     
         9 . The sport ball of    claim 1   , wherein the sport ball is a football, volley ball or playground ball.  
     
     
         10 . A sport ball according to    claim 3   , wherein the rebound characteristics of the ball comprise the rebound distance of the ball when dropped vertically from a height of 72 inches, and the ball has a rebound of 50-57 inches.  
     
     
         11 . A sport ball according to    claim 10   , wherein the difference between the maximum and minimum rebound heights of the ball is 5.5 inches or less.  
     
     
         12 . A sport ball according to    claim 11   , wherein the ball has a coefficient of restitution of 0.750-0.813.  
     
     
         13 . A sport ball according to    claim 12   , wherein the delta COR of the ball is 0.051 or less.  
     
     
         14 . A sport ball according to    claim 12   , wherein the delta COR of the ball is 0.036 or less.  
     
     
         15 . A sport ball according to    claim 3   , wherein the difference between the maximum COR and minimum COR of the ball when the ball is dropped repeatedly with different orientations is 0.051 or less.  
     
     
         16 . A sport ball according to    claim 3   , wherein the difference between the maximum COR and minimum COR of the ball when the ball is dropped repeatedly with different orientations is 0.036 or less.  
     
     
         17 . A sport ball according to    claim 4   , wherein the difference between the maximum COR and minimum COR of the ball when the ball is dropped repeatedly with different orientations is 0.051 or less.  
     
     
         18 . A sport ball according to    claim 1   , wherein the rebound characteristics of the ball comprise the rebound consistency of the ball.  
     
     
         19 . A sport ball according to    claim 1   , wherein the rebound characteristics of the ball include the minimum critical ratio of the ball, wherein the minimum critical ratio is equal to (half period of component vibration)/(duration of the ball's impact with the floor).  
     
     
         20 . The sport ball of    claim 1   , wherein the self-contained inflation mechanism is a pump.  
     
     
         21 . A sport ball having a self contained inflation mechanism and exhibiting a minimum critical ratio equal to: (half period of component vibration)/(duration of the ball's impact with the floor), wherein the critical ratio is selected such that the sport ball having the self contained inflation mechanism exhibits substantially the same minimum critical ratio as a comparable sport ball without a self contained inflation mechanism.  
     
     
         22 . The sport ball of    claim 21   , wherein the sport ball is a basketball.  
     
     
         23 . The sport ball of    claim 21   , wherein the sport ball is a soccer ball.  
     
     
         24 . The sport ball of    claim 21   , wherein the sport ball comprises a cover wherein the material is selected from the group consisting of leather, synthetic leather, composites, rubber materials and combinations thereof.  
     
     
         25 . The sport ball of    claim 21   , wherein the sport ball is a football, volley ball or playground ball.  
     
     
         26 . The sport ball of    claim 21   , wherein the self contained inflation mechanism is a pump.  
     
     
         27 . A method of determining the critical ratio of an inflated sport ball, comprising the steps of: 
 a) determining the duration of the ball's impact with the floor;    b) determining the half period of component vibration; calculating the critical ratio by dividing the half period of component vibration, (b), by the duration of the ball's impact with the floor, (a).    
     
     
         28 . A method according to    claim 27   , wherein the steps (a) and (b) are performed repeatedly with different ball orientations.  
     
     
         29 . The method of    claim 27   , wherein the sport ball is a basketball.  
     
     
         30 . The method of    claim 27   , wherein the critical ratio is 0.95 or greater, and the basketball is suitable for play.  
     
     
         31 . The method of    claim 27   , wherein the sport ball is a football, volley ball, soccer ball or playground ball.  
     
     
         32 . A sport ball which comprises a self-contained inflation mechanism, the sport ball having rebound characteristics determined by dropping the ball repetitively with different orientations from a height of 72 inches onto a wooden floor and measuring the rebound height that occurs when respective surface areas of the ball contact the floor, 
 wherein the ball has rebound characteristics according to which the maximum rebound height minus the minimum rebound height is less than or equal to 5.5 inches.