Tubular baseball bats with variable stiffened barrels

Abstract

Tubular baseball bats comprised of an elongated handle portion and a striking or barrel portion wherein the barrel portion has variable stiffness along its length. One such bat has a circumferential low cost, low weight stiffener generally located in the sweetspot area designed to increase radial stiffness in a controlled manner which results in decreasing the bat performance to meet a changed bat performance standard and can be applied at low cost to both used field returned bats and bats being newly manufactured. Further, new tubular polymer composite bats can be designed with increased radial stiffness generally located in the sweetspot area or with radial stiffness graduated from highest, generally in the sweetspot area, to lowest at the barrel ends. All bats of the present invention result in calculated bat performance to meet applicable regulatory standards while also increasing the sweetspot size.

1 . A tubular baseball bat with a longitudinal axis comprising a cylindrical handle portion on for gripping, a cylindrical tubular barrel portion of given length for striking, the barrel portion having a barrel wall with a sweet spot area within its length, and a tapered bridging portion connecting the handle portion and the barrel portion, wherein the barrel portion has:
 a) a distal end remote from the handle;   b) a proximal end where the tapered portion connects to the handle portion;   c) a mid-section within the barrel portion, the mid-section having of shorter length than the length of the barrel portion and including the sweet spot area;   d) two lateral regions commencing immediately adjacent to and extending respectively on each side of the mid-section towards the distal and proximal ends respectively, and   e) a radial stiffness for the barrel wall at each location along the length of the barrel portion,   the radial stiffness of the barrel wall being greater in the mid-section of the barrel portion than in the two lateral regions of the barrel portion   to provide a flattened batting performance over the mid-section that is flattened compared to what otherwise would exist without the presence of the greater radial stiffness in the mid-section and which is characteristic of an enlarged sweet spot.   
   
   
       2 . The bat as described in  claim 1 , wherein the barrel portion comprises a barrel wall of polymer composite material and the polymer composite material provides a radial stiffness in the barrel wall within the mid-section of the barrel portion which is greater than the radial stiffness of the barrel wall within the lateral regions. 
   
   
       3 . The bat as described in  claim 2 , wherein the barrel wall has a thickness and wherein the polymer composite material of the barrel wall is of a greater thickness within the barrel wall of the mid-section than in the lateral regions by at least 8⅓% to provide the barrel wall with a radial stiffness in the mid-section that is greater than the radial stiffness of the barrel wall within the two lateral regions of the barrel portion. 
   
   
       4 . The bat as described in  claim 1 , wherein the barrel wall has a thickness and the thickness of the barrel wall in the mid-section is greater than the thickness of the barrel wall in the lateral regions by at least 8⅓% whereby the radial stiffness of the barrel wall in the mid-section of the barrel portion is greater than the radial stiffness of the barrel wall in the lateral regions. 
   
   
       5 . The bat as described in  claim 4 , wherein the thickness of the mid-section of the barrel portion is greater than the thickness of the lateral regions at their thinnest parts by at least 5%. 
   
   
       6 . The bat as described in  claim 1 , wherein the barrel portion has inner and outer surfaces, the barrel portion comprising a stiffener positioned along the mid-section of the barrel portion adjacent the inner or outer surface of the barrel portion, whereby the radial stiffness of the barrel wall with the stiffener present along the mid-section of the barrel portion is greater than the radial stiffness of the barrel wall in the lateral regions. 
   
   
       7 . The bat as described in  claim 6 , wherein the stiffener comprises an area of varied barrel thickness. 
   
   
       8 . The bat as described in  claim 6 , wherein the stiffener has a stiffener wall having a thickness of between 0.005 inches 0.040 inches. 
   
   
       9 . The bat as described in  claim 6 , wherein the stiffener has a length of 2 to 6 inches. 
   
   
       10 . The bat as described in  claim 6 , wherein the stiffener is unbonded along its length to the barrel portion. 
   
   
       11 . The bat as described in  claim 6 , wherein the stiffener is bonded at least partially along its length to the barrel portion. 
   
   
       12 . The bat as described in  claim 6 , wherein the stiffener is bonded fully along its length to the barrel portion. 
   
   
       13 . The bat as described in  claim 6  wherein the stiffener is located on the inner surface of the barrel portion. 
   
   
       14 . The bat as described in  claim 6 , wherein the stiffener is located on the external surface of the barrel portion. 
   
   
       15 . The bat as described in  claim 6 , wherein the stiffener is composed of polymer composite material which comprises a resin matrix encapsulating reinforcement fibers wherein the resin is selected from the group of resin consisting of epoxy, vinyl ester, polyester, urethane, nylon, and mixtures thereof and wherein the reinforcement fibers are selected from the group consisting of fiberglass, graphite, carbon, aramid, boron, nylon fibers and mixtures thereof. 
   
   
       16 . The bat as described in  claim 1 , wherein the mid-section has a length that is less than 33.3% of the length of the barrel portion. 
   
   
       17 . The bat as described in  claim 16 , wherein the mid-section has a length that is less than 25% of the length of the barrel portion. 
   
   
       18 . The bat as described in  claim 16 , wherein the mid-section has a length that is less than 16⅔% of the length of the barrel portion. 
   
   
       19 . The bat as described in  claim 2 , wherein the bat consists of polymer composite material which comprises a resin matrix encapsulating reinforcement fibers wherein the resin is selected from the group of resin consisting of epoxy, vinyl ester, polyester, urethane, nylon, and mixtures thereof and wherein the reinforcement fibers are selected from the group consisting fiberglass, graphite, carbon, aramid, boron, nylon fibers and mixtures thereof. 
   
   
       20 . A tubular bat with a longitudinal axis comprising a cylindrical handle portion for gripping, a cylindrical tubular barrel portion of given length for striking, the barrel portion having a barrel wall with a barrel wall thickness and distinct locations including a sweet spot area within its length, and a tapered bridging portion connecting the handle portion and the barrel portion, wherein the barrel portion has:
 a) a distal end remote from the handle;   b) a proximal end where the tapered portion connects to the handle portion;   c) a mid-section within the barrel portion, the mid-section being of shorter length than the length of the barrel portion and including the sweetspot area;   d) two lateral regions commencing immediately adjacent to and extending respectively on each side of the mid-section towards the distal and proximal ends respectively, and   e) a radial stiffness for the barrel wall at each location along the length of the barrel portion   
     wherein the barrel wall thickness in the barrel mid-section that contains the sweet spot area is greater than the thickness of the barrel wall in the lateral regions by at least 5% over the thinnest portion of the barrel wall in the lateral regions, and 
     wherein the barrel wall of the barrel portion consists essentially of polymer composite material, and 
     wherein the area of greater thickness in the barrel mid-section is formed of the same general material as the underlying barrel wall portion with which it is associated, to provide the barrel wall with a radial stiffness in the mid-section that is greater than the radial stiffness of the barrel wall within the two lateral regions of the barrel portion and thereby with an enlarged sweet spot. 
   
   
       21 . The bat as described in  claim 20 , wherein the greater radial stiffness in the mid-section provides the bat with a relatively flattened batting performance level along such mid-section compared to the batting performance level along the immediately adjacent portions of the lateral regions on the respective sides of the mid-section. 
   
   
       22 . The bat as described in  claim 21 , wherein the thickness of the total barrel wall is 0.005 to 0.040 inches greater in the barrel mid-section than in the two lateral regions. 
   
   
       23 . The bat as described in  claim 22 , wherein the radial stiffness of the barrel wall in the mid-section provides the bat with a batting performance level that is reduced to substantially the batting performance level of the portions of the lateral regions immediately adjacent to each side of the mid-section. 
   
   
       24 . The bat as described in  claim 20 , wherein the increased thickness of the barrel wall in the barrel mid-section is the only part of the barrel portion that is of increased thickness over the thickness of the barrel wall in the lateral regions. 
   
   
       25 . The bat as described in  claim 20 , wherein the barrel mid-section of increased thickness is centered around the middle of the barrel. 
   
   
       26 . The bat as described in  claim 20 , wherein the lateral regions start from 1″ to up to but not including 2″ from the center of the mid-section and extend towards the proximal and distal barrel ends. 
   
   
       27 . The bat as described in  claim 20 , wherein the mid-section has a length that is less than 50% of the length of the barrel portion. 
   
   
       28 . The bat as described in  claim 20 , wherein the bat is a single wall bat. 
   
   
       29 . The bat as described in  claim 20 , wherein the bat is a multi-wall bat, which includes a double wall bat. 
   
   
       30 . The bat as described in  claim 20 , wherein the barrel wall thickness on either side of the barrel mid-section that contains the sweet spot area is graduated towards a decreasing thickness within the lateral regions. 
   
   
       31 . The bat as described in  claim 24 , wherein the barrel wall thickness in the barrel mid-section that contains the sweet spot area is greater than the thickness of the barrel wall in the lateral regions by at least 8⅓% over the thinnest portion of the barrel wall in the lateral regions, 
   
   
       32 . The bat as described in  claim 22 , wherein the thickness of the total barrel wall is greater in the barrel mid-section than in the two lateral regions by an amount selected from the group of ranges consisting of 0.010 inches to 0.040 inches in thickness, 0.015 inches to 0.040 inches in thickness, and 0.015 inches to 0.030 inches. 
   
   
       33 . The bat as described in  claim 20 , wherein the bat is a double-wall bat having an exterior frame with a tubular barrel and an inner tubular insert within the barrel, the insert having a thickened portion extending internally within the insert along the mid-section of the barrel to provide the barrel wall with its barrel wall portion of greater thickness.