RACKET
A racket includes a head 8 , a first foam 6 a and a second foam 6 b . The head 8 is formed from a fiber reinforced resin. The head 8 has an inside part 16 , an outside part 18 and two middle parts 20 . The foams 6 are joined to respective inner surfaces of the middle parts 20 . Each foam 6 includes a matrix and a large number of bubbles dispersed in the matrix. In a cross section of the head 8 , a ratio of an area of the foam 6 to an area of a space is equal to or greater than 5% and equal to or less than 50%. The foam 6 has a density of equal to or less than 0.30 g/cm 3 . The foam 6 has a 25% CLD measured in accordance with “JIS K6254” standard of equal to or less than 0.10 MPa.
1 . A racket comprising:
a frame formed from a fiber reinforced resin and being hollow; and
a foam joined to a part of an inner surface of the frame and containing a large number of bubbles.
2 . The racket according to claim 1 , wherein in a cross section of the racket, a ratio of an area of the foam to an area of a space of the frame is equal to or greater than 5% and equal to or less than 50%.
3 . The racket according to claim 1 , wherein the foam has a density of equal to or less than 0.50 g/cm 3 .
4 . The racket according to claim 1 , wherein the foam has a 25% CLD measured in accordance with “JIS K6254” standard of equal to or less than 0.10 MPa.
5 . The racket according to claim 1 , wherein a central angle θ of the foam at a center point of the frame is equal to or greater than 100°.
6 . A method for manufacturing a racket comprising the steps of:
laminating a foam piece containing a large number of bubbles onto a part of a surface of a prepreg including a matrix resin and a large number of fibers;
winding the prepreg into a tubular shape to locate the foam piece on an inner surface of the prepreg; and
curing the matrix resin.