Training bat

Abstract

A training bat 100 includes a core bar 170 placed within a space formed in a bat body 120; a weight 130 movable within the space; and a biasing means for applying a biasing force to the weight 130. The biasing means includes a first compression spring 150 having a coil and a second compression spring 160 having a coil. The core bar 170 is configured to pass through the coil of the first compression spring 150, the through hall of the weight 130 and the coil of the second compression spring 160. The weight 130 is movable between an initial position and a tip position. The biasing means is configured to apply the biasing force to the weight 130 in a direction where the weight 130 returns from the tip position back to the initial position, when the weight 130 is positioned at the tip position.

1 . A training bat comprising:
 a grip portion;   a bat body, wherein a space is formed within at least a part of the bat body;   a core bar placed within the space;   a weight movable within the space; and   a biasing means for applying a biasing force to the weight, the biasing means including a first compression spring having a coil and a second compression spring having a coil,   wherein a through hall is formed within the weight such that the core bar can pass through the weight,   wherein the core bar is configured to pass through the coil of the first compression spring, the through hall of the weight and the coil of the second compression spring, such that the first compression spring is positioned at a position closer to the grip portion than the weight and the second compression spring is positioned at a position closer to a tip portion of the training bat than the weight,   wherein the weight is movable between an initial position and a tip position, the initial position is a position closer to the tip portion of the training bat than the initial position along a longitudinal direction of the training bat,   wherein the biasing means is configured to apply the biasing force to the weight in a direction where the weight returns from the tip position back to the initial position, when the weight is positioned at the tip position, and   wherein both ends of the first compression spring are free ends and both ends of the second compression spring are free ends.   
     
     
         2 . A training bat according to  claim 1 , wherein, when the weight is positioned at the initial position, the first compression spring is in a compressed state and the second compression spring is in a compressed state or a neutral state. 
     
     
         3 . A training bat according to  claim 1 , wherein the winding number of the second compression spring per unit length is equal to the winding number of the first compression spring per unit length. 
     
     
         4 . A training bat according to  claim 1 , wherein the winding number of the second compression spring per unit length is less than the winding number of the first compression spring per unit length. 
     
     
         5 . A training bat according to  claim 1 , wherein the second compression spring is a conical compression spring, and the second compression spring is configured such that the radius of the coil of the second compression spring is monotonically increased as the coil of the second compression spring becomes closer to the tip portion of the training bat. 
     
     
         6 . A training bat comprising:
 a grip portion;   a bat body, wherein a space is formed within at least a part of the bat body;   a core bar placed within the space;   a weight movable within the space; and   a biasing means for applying a biasing force to the weight, the biasing means including a first compression spring having a coil and a second compression spring having a coil,   wherein a through hall is formed within the weight such that the core bar can pass through the weight,   wherein the core bar is configured to pass through the coil of the first compression spring, the through hall of the weight and the coil of the second compression spring, such that the first compression spring is positioned at a position closer to the grip portion than the weight and the second compression spring is positioned at a position closer to a tip portion of the training bat than the weight,   wherein the weight is movable between an initial position and a tip position, the initial position is a position closer to the tip portion of the training bat than the initial position along a longitudinal direction of the training bat,   wherein the biasing means is configured to apply the biasing force to the weight in a direction where the weight returns from the tip position back to the initial position, when the weight is positioned at the tip position, and   wherein the winding number of the second compression spring per unit length is less than the winding number of the first compression spring per unit length.   
     
     
         7 . A training bat comprising:
 a grip portion;   a bat body, wherein a space is formed within at least a part of the bat body;   a core bar placed within the space;   a weight movable within the space; and   a biasing means for applying a biasing force to the weight, the biasing means including a first compression spring having a coil and a second compression spring having a coil,   wherein a through hall is formed within the weight such that the core bar can pass through the weight,   wherein the core bar is configured to pass through the coil of the first compression spring, the through hall of the weight and the coil of the second compression spring, such that the first compression spring is positioned at a position closer to the grip portion than the weight and the second compression spring is positioned at a position closer to a tip portion of the training bat than the weight,   wherein the weight is movable between an initial position and a tip position, the initial position is a position closer to the tip portion of the training bat than the initial position along a longitudinal direction of the training bat,   wherein the biasing means is configured to apply the biasing force to the weight in a direction where the weight returns from the tip position back to the initial position, when the weight is positioned at the tip position, and   wherein the second compression spring is a conical compression spring, and the second compression spring is configured such that a radius of the coil of the second compression spring is monotonically increased as the coil of the second compression spring becomes closer to the tip portion of the training bat.   
     
     
         8 . A training bat according to  claim 1 , further comprising:
 a guide portion for guiding the core bar such that a longitudinal direction of the core bar coincides with the longitudinal direction of the training bat.   
     
     
         9 . A training bat according to  claim 1 , wherein the tip portion of the training bat is configured to be opened or closed, and the training bat is configured such that at least one of the first compression spring, the weight, and the second compression spring can be exchanged when the tip portion of the training bat is opened. 
     
     
         10 . A training bat according to  claim 1 , wherein the training bat is a metal bat. 
     
     
         11 . A training bat according to  claim 6 , further comprising:
 a guide portion for guiding the core bar such that a longitudinal direction of the core bar coincides with the longitudinal direction of the training bat.   
     
     
         12 . A training bat according to  claim 6 , wherein the tip portion of the training bat is configured to be opened or closed, and the training bat is configured such that at least one of the first compression spring, the weight, and the second compression spring can be exchanged when the tip portion of the training bat is opened. 
     
     
         13 . A training bat according to  claim 6 , wherein the training bat is a metal bat. 
     
     
         14 . A training bat according to  claim 7 , further comprising:
 a guide portion for guiding the core bar such that a longitudinal direction of the core bar coincides with the longitudinal direction of the training bat.   
     
     
         15 . A training bat according to  claim 7 , wherein the tip portion of the training bat is configured to be opened or closed, and the training bat is configured such that at least one of the first compression spring, the weight, and the second compression spring can be exchanged when the tip portion of the training bat is opened. 
     
     
         16 . A training bat according to  claim 7 , wherein the training bat is a metal bat.