Identifying the sweet spot of a bat

Abstract

A test fixture for identifying the sweet spot of a bat includes one or more vibration absorbers, which may include cuffs, caps, and cuff/accelerometer combinations. An impact mass driven by motors strikes the bat at a series of locations along the barrel of the bat while the magnitude of vibration at the handle of the bat is measured by an accelerometer. The sweet spot is identified based on the minimum of the maximum measured acceleration values. The vibration absorbers inhibit gross movement of the bat and accelerate quiescence of oscillatory vibration of the bat between strikes, thereby reducing test time and increasing accuracy.

What is claimed is: 
     
         1 . An apparatus for analyzing a bat characterized by a handle, a barrel and a transition, comprising:
 at least one vibration absorber adapted to inhibit gross movement of the bat and quiesce oscillatory vibration of the bat;   an accelerometer adapted to sense acceleration at the handle of the bat; and   an impact mass adapted to strike a plurality of locations on the barrel of the bat.   
     
     
         2 . The apparatus of  claim 1  wherein the at least one vibration absorber comprises at least one of a vibration absorber cap, vibration absorber cuff, and vibration absorber cuff with accelerometer. 
     
     
         3 . The apparatus of  claim 1  wherein the at least one vibration absorber comprises a vibration absorber cap configured to contact with the barrel end of the bat and a vibration absorber cuff configured to contact the transition of the bat. 
     
     
         4 . The apparatus of  claim 1  wherein the at least one vibration absorber comprises a vibration absorber cap configured to contact the knob of the bat, and a vibration absorber cuff configured to contact the transition of the bat. 
     
     
         5 . The apparatus of  claim 1  wherein the at least one vibration absorber comprises a first vibration absorber cap configured to contact the knob of the bat, and a second vibration absorber cap configured to contact the barrel end of the bat. 
     
     
         6 . The apparatus of  claim 1  wherein the at least one vibration absorber comprises a vibration absorber cuff with accelerometer configured to attach to the handle of the bat and a vibration absorber cuff configured to attach to the transition of the bat. 
     
     
         7 . The apparatus of  claim 1  wherein the at least one vibration absorber comprises a vibration absorber cuff with accelerometer configured to attach to the handle of the bat and a vibration absorber cap configured to contact the barrel end of the bat. 
     
     
         8 . The apparatus of  claim 1  further comprising the vibration absorber cuff being adapted to be repositioned along the transition of the bat. 
     
     
         9 . The apparatus of  claim 1  further comprising the vibration absorber cuff having a vibration damping layer disposed within a rigid collar. 
     
     
         10 . The apparatus of  claim 9  in which the vibration damping layer comprises one or more of resilient foam, rubber, cork, polyurethane, and polyvinyl chloride. 
     
     
         11 . The apparatus of  claim 9  further comprising the vibration damping layer and rigid collar characterized by a split cylindrical shape having two halves connected by a hinge. 
     
     
         12 . The apparatus of  claim 1  further comprising the vibration absorber cap having a single open concave end that defines an opening characterized by a spherical cap, spherical segment, conical, or truncated conical shape. 
     
     
         13 . The apparatus of  claim 12  wherein the vibration absorber cap comprises a cylindrical rigid receiver with a sidewall, enclosed bottom, and open top. 
     
     
         14 . The apparatus of  claim 13  wherein the vibration absorber cap comprises a vibration damping layer adapted to fit against the sidewall and enclosed bottom of the receiver and a concave curved opening that defines a void shaped as a spherical cap, spherical segment, cone or truncated cone for receiving the barrel end of the bat. 
     
     
         15 . The apparatus of  claim 1  wherein the vibration absorber cuff and the vibration absorber cap are configured to align a center axis of the bat perpendicular with a first linear axis of strike travel of the impact mass and parallel with a second linear axis of relocation travel of the impact mass. 
     
     
         16 . The apparatus of  claim 15  further comprising motors configured to linearly move the impact mass in the first linear axis to strike the bat with a predetermined force and to linearly move the impact mass in the second axis to change the location of impact along the barrel between successive strikes. 
     
     
         17 . The apparatus of  claim 16  further comprising a controller with a microprocessor and memory adapted to controls the motors to cause the impact mass to strike the bat at a series of locations, at predetermined distance increments, along the barrel of the bat while measuring responsive acceleration at the handle of the bat using the accelerometer. 
     
     
         18 . The apparatus of  claim 17  further comprising the controller being configured to identify a sweet spot of the bat based on the measured acceleration values and present the results on a display. 
     
     
         19 . The apparatus of  claim 18  further comprising the controller being configured to cause the location of the sweet spot to be marked on the bat. 
     
     
         20 . A method for identifying a sweet spot of a bat characterized by a handle, a barrel and a transition, comprising:
 striking the bat at a series of locations along the barrel of the bat;   measuring maximum acceleratory response to each strike at the handle of the bat;   quiescing oscillatory vibration of the bat and inhibiting gross movement of the bat with at least one vibration absorber; and   identifying the sweet spot based on the location corresponding to minimum of the maximum acceleratory responses.