Racket for playing a game with a ball

(19)

(11)

EP 0 317 711 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	16.05.1990 Bulletin 1990/20

(43)	Date of publication A2:
	31.05.1989 Bulletin 1989/22

(21)	Application number: 88112740.1

(22)	Date of filing: 04.08.1988

(51)	International Patent Classification (IPC)⁴: A63B 49/00, A63B 59/00

(84)	Designated Contracting States:
	AT BE CH DE ES FR GB GR IT LI LU NL SE

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Priority:

04.08.1987 US 79991

(71)	Applicant: WILSON SPORTING GOODS COMPANY
	River Grove Illinois 60171 (US)

(72)	Inventor:
	Karasek, Mark L Villa Park Il 60181 (US)

(74)	Representative: Hiebsch, Gerhard F., Dipl.-Ing. et al
	Postfach 464 D-78204 Singen D-78204 Singen (DE)

(56)

References cited: :

(54)	Racket for playing a game with a ball

(57) The stiffness of a tennis racket is adjusted so that the first mode of bending of the racket under free-free constraint conditions is between 170 Hz and 250 Hz preferably between 200 Hz and 210 Hz. The second mode of bending under clamped-free constraint conditions is between 215 Hz and 315 Hz and preferably between 230 Hz and 265 Hz.

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