Abstract: A method of making a golf club includes the use of an inner tube, which is made of an elastic and refractory material and is wrapped orderly onto with at least a matrix layer of thermoplastic material and with at least a reinforcing layer of long fiber material so as to form a tubular body having a laminated outer shell. The tubular body is heated in a molding tool up to a temperature corresponding to the melting point of the thermoplastic plastic material. A pressurized gas is introduced into the tubular body to force the molten thermoplastic plastic material to diffuse evenly into the interstices of fiber bundles making up the long fiber material. After being cooled, the molding tool is opened to remove therefrom the golf club made of plastic composite material. Such golf club is tough, light in weight, and has an excellent shock-absorbing quality.

Abstract: A highly shock-absorbing racket frame of fiber reinforcing plastic material comprising an outer shell made from a plurality of fiber fabric sheets preimpregnated in epoxy resin and made up of fibers arranged in a predetermined orientation. The outer shell located in the head portion and the shaft portion is provided with at least one shock-absorbing portion fitted into a tubular bridging in a manner such that they are adhered securely. A first reinforcing is used to cover across a bordering portion of one end of the bridging and outer shell in addition to a surface adjacent to bridging and outer shell. A second reinforcing is used to cover across the bordering portion of another end of the bridging and outer shell in addition to the surface adjacent to the bridging and outer shell. The shock wave generated in the head portion is effectively absorbed and mitigated by the shock-absorbing portion.

Abstract: A sports racket frame comprises an outer shell made of a fiber-reinforced composite. Located at a predetermined area of the outer shell encasing the handle portion are slits in the shell and a plurality of strength-reinforcing and shock-absorbing inlay pieces which reduce effectively the shock wave originating from the ball-hitting surface to a minimum and to give the racket frame an added elasticity and rigidity.

Abstract: A ball bat comprises an impact portion, a grip portion, and a flexible bending portion situated between the impact portion and the grip portion. The bat is characterized in that it comprises a fiber-reinforced plastic casing of a predetermined thickness. The slits of a predetermined number are constructed in the casing located at the junction area of flexible bending portion and grip portion. The number of fibers incised to form slits is in a predetermined proportion to the total number of fibers contained in the casing located at the junction area, with the ratio being in the range of 5% to 95%. The slits serve to obstruct the transmission of shock from the impact portion to the grip portion of the ball bat. Rigidity and elasticity of the impact portion are different from those of grip and flexible bending portions by virture of an existence of slits disposed in the latter.

Abstract: A baseball bat formed from a plurality of laminations. The laminations are held together through the engagement of dovetail shaped grooves and ridges located on the mating surfaces of the laminations. Layers of resin impregnated carbon fiber webs are sandwiched between the wooden laminations so as to provide strength and shock absorbing characteristics.

Abstract: A composite construction of a golf club head including a plurality of laminated wooden layers and a plurality of resin impregnated fiber layers provided between said wooden layers characterized in that each of said wooden layers is provided with engagement surfaces for interengaging with other wooden layers. The engagement surfaces includes a plurality of tongue-and-groove surfaces in the direction perpendicular to the direction of the stroke.

Abstract: A composite structural member for ski construction comprises at least two wooden layers and a reinforcing resin impregnated fiber layer adhesively bonded to and sandwiched between the wooden layers characterized in that the wooden layers are provided with raised bars which are meshed each other at their opposite sides.

Abstract: A racket frame is made by molding a thermosetting resin composition together with reinforcing fibers. Molds are made of flexible strip members, such as plastics, wood pulp, paper pulp, wood, bamboo, etc., which are bent to form a racket frame in a fitting, thereby reducing the production cost incurred in fabrication of expensive molds. The formed racket frame has no shell and core structure.

Abstract: A method of producing a racket frame, in which multiple layers of wooden strips are laminated to form a racket frame. An elongate groove is made at least in a wooden strip of mid layer on the side perpendicular to the string of the racket. The groove includes a shallow elongate central portion and two deeper elongate portions joining longitudinally with the central portion. A reinforcing material is filled in the groove and the mid layer is then plied with the wooden strips of other layers by means of adhesive. The preformed frame is heated and the reinforcing material sets in the groove and form an integral body therewith.The racket frame comprises, a plurality of elongate wooden strips laminated and fabricated to form a frame; and a reinforcing material being sandwiched in the mid part of the frame. The reinforcing material extends longitudinally along the frame and have a structure in which the cross section is narrow at the central part and broad about two ends.