Cette méthode de calcul d'un paramètre (P) représentatif de l'endurance d'un joueur de tennis au cours d'une période de jeu comprenant une série de sessions de jeu, caractérisée en ce qu'elle comprend au moins des étapes consistant à : a) mesurer, à l'aide d'un système de mesure comprenant des capteurs implantés sur une raquette (1) utilisée par le joueur, l'accélération linéaire et la vitesse angulaire de la raquette (1) lors de chaque coup frappé par le joueur au cours d'une session de jeu, b) calculer (100), au moyen d'une unité de calcul, la puissance (W) développée par le joueur lors de chaque coup à partir des accélérations linéaires et des vitesses angulaires mesurées à l'étape a), calculer (101) au moyen de l'unité de calcul, la puissance moyenne (Wm) développée par le joueur pendant la dernière session de jeu, la puissance moyenne étant définie comme la moyenne des puissances (W) développées lors de chaque coup par le joueur calculées à l'étape b), d) calculer (102) au moyen de l'unité de calcul l'énergie (E) dépensée par le joueur pendant la dernière session de jeu, l'énergie dépensée étant égale au nombre (n) de coups exécutés par le joueur au cours de la dernière session de jeu multipliée par la puissance moyenne (Wm) calculée à l'étape c) élevée à un exposant (i) prédéterminé, e) calculer (103) au moyen de l'unité de calcul la valeur du paramètre (P), cette valeur étant définie par le produit du nombre (N) de sessions de jeu réalisées par semaine au cours de la période de jeu, multiplié par l'énergie (E) calculée à l'étape d).

The present invention relates to a racket assembly, comprising a racket (20) including a frame (24) having a head (26), a throat (28) and a handle (30), at least one sensor assembly (36) operatively coupled to the racket (20) and configured to generate a signal indicative of at least one parameter related to use of the racket (20), and a processor (14) configured to receive the signal as an input and to generate an output based on said signal, wherein the at least one sensor assembly (36) comprises at least one accelerometer (40) to measure acceleration associated with racket movement and wherein the processor is configured to determine the speed of a ball which is struck by the racket (20) on the basis of the measured acceleration.

A method for manufacturing an object having a potential {x} that is generated in response to a field {f} applied thereto. A computerized mathematical model (801) of the object is generated by discretizing a geometric model of the object into a plurality of finite elements (802) and specifying values for the field {f} and potential {x} relative to the finite elements (802). The material properties (804) of the finite elements (802) are specified to have a particular symmetry and a material property (804) matrix [k] is calculated based on the relationship {f}=[k]{x} and the specified symmetry. Material property (804) coefficients are extracted from the material property (804) matrix [k] for each finite element (802) in the computerized mathematical model (801) and the extracted material property (804) coefficients are compared to material property (804) coefficients for known materials to match the extracted material property (804) coefficients to the material property (804) coefficients for known materials. Manufacturing parameters (805) for controlling manufacturing equipment are determined based on the matched material property (804) coefficients and the manufacturing equipment is controlled in accordance with the determined manufacturing parameters (805) to thereby manufacture the object.

It is an object of the present invention to improve drawbacks in conventional technology and provide a fiber-reinforced composite material having both an excellent static strength property and impact resistance, and an epoxy resin composition for obtaining the fiber-reinforced composite material. More particularly, it is the object of the present invention to provide the epoxy resin composition that gives a cured material having a high elastic modulus, a high heat resistance, a high plastic deformation capacity and a high toughness.

The epoxy resin composition containing following [A] to [D], a prepreg obtained by impregnating a fiber substrate with the epoxy resin composition, a fiber-reinforced composite material obtained by curing the prepreg and a tubular body thereof.

[A] 10 to 60 parts by weight of an amine type epoxy resin,

[B] 40 to 90 parts by weight of a bisphenol-type epoxy resin,

[C] 1 to 10 parts by weight of dicyandiamide or a derivative thereof, and

[D] 1 to 10 parts by weight of at least one block copolymer selected from the group consisting of S-B-M, B-M and M-B-M.

Die vorliegende Erfindung betrifft eine Dämpfungsvorrichtung (1) für Ballspielschläger. Die erfindungsgemäße Dämpfungsvorrichtung weist mindestens ein Dämpfungselement auf, das einen Fuß- bzw. Basisbereich (7), einen Kopfbereich (3) und einen zwischen dem Fuß- und dem Kopfbereich angeordneten Hals- bzw. Verbindungsbereich (5) hat. Hierbei erlaubt das Vorsehen eines Hals- bzw. Verbindungsbereichs die Ausbildung eines optimalen Abstands zwischen Fuß- bzw. Basisbereich und Kopfbereich bzw. eine optimale und sichere Positionierung des Kopfbereichs in der Bespannungsebene mit einem bevorzugten Abstand zum Herzbereich des Schlägers. Bevorzugt ist der Halsbereich zumindest in Breiten- oder Dickenrichtung der erfindungsgemäßen Dämpfungsvorrichtung gegenüber dem Fuß- bzw. Basisbereich und/oder dem Kopfbereich verjüngt bzw. eingeschnürt ausgebildet.

The frame of a racket for playing tennis, badminton or squash incorporated between two parts thereof a non-liquid substance which is perfumed with a scent of animal and/or plant and/or synthetic nature. In a preferred embodiment the two sides of the frame are interconnected near the handle by a yoke 10 made in these inter-abutting sections 11, 12 and a perfumed substance in the form of a micro-encapsulated powder is disposed between the abutting faces of the sections A gap is formed for an instant between said faces when the playing piece is struck, permitting release of scent for a correspondingly short time.

The improved racquet (1) has a strung surface (11) which is larger in area than the strung surface of a conventional racquet, and in which the strung area (11) is both larger in length and width than the strung area of a conventional racquet. However, the overall weight and balance of a conventional racquetball racquet which have proven necessary for good playing characteristics for all such racquets have been maintained. The racquet (1) has synergistically combined the weight of the racquet, the stiffness of the frame (3), and the response characteristics to create a racquet of sufficient durability with a larger "sweet spot" to facilitate the palying of the sport and to increase the level of skill, particularly of the novice and intermediate players. The racquet (1) has an overall length of 18 ½ inches to 14 ³f₄ inches, a weight of 220 grams to 270 grams, and a center of gravity at a location within a range of ¾ inch toward the handle (3) and ½inch toward the head (2) as measured from the longitudinal center point of the racquet.