Tennis racket and method for manufacturing the same

Abstract

A tennis racket includes a frame that surrounds a hitting face for hitting a ball, wherein a foam material is provided inside two side portions of the frame on opposite sides of a predetermined area of the hitting face, and the two side portions of the frame have a strength that is higher than a strength of another portion of the frame.

What is claimed is: 
     
         1 . A tennis racket comprising:
 a frame that surrounds a hitting face for hitting a ball; wherein a foam material is provided inside two side portions of the frame on opposite sides of a predetermined area of the hitting face, and the two side portions of the frame have a strength that is higher than a strength of another portion of the frame.   
     
     
         2 . A tennis racket according to  claim 1 ,
 wherein a foam material for filling that is different from the foam material is provided inside the another portion of the frame.   
     
     
         3 . A tennis racket according to  claim 1 ,
 wherein the foam material is provided inside the another portion of the frame, and   an amount of the foam material in the two side portions is different from an amount of the foam material in the another portion.   
     
     
         4 . A tennis racket according to  claim 1 ,
 wherein the frame has a frame portion that surrounds the hitting face on one end side, and has a grip portion on another end side, and   the predetermined area is an area on the one end side than substantially a middle of the hitting face.   
     
     
         5 . A tennis racket according to  claim 4 ,
 wherein when a position of the one end of the frame portion is set at 0 degrees relative to a center of the hitting face, the foam material is provided in a range of 20 degrees to 60 degrees of the frame portion.   
     
     
         6 . A method for manufacturing a tennis racket including a frame having a first strength and a second strength that is higher than the first strength, comprising the steps of:
 arranging a foam material on a resin sheet in an area that corresponds to the second strength;   forming a sheet tube by wrapping the resin sheet, on which the foam material is arranged, into a cylindrical shape; and   forming a frame in which the resin sheet and the foam material are integrally molded, by bending the sheet cylinder to be set in a die, and then causing the foam material to undergo foaming.