Abstract: A ball for a ball game includes an elastic bladder having the form of a spherical hollow body into which compressed air is charged, a reinforced layer formed on a whole surface of the bladder, and a plurality of leather panels bonded onto the reinforced layer directly or through a cover rubber layer, wherein a peripheral edge portion of the leather panel is folded toward an inside and a thickness adjusting member for eliminating a difference in step caused by the folding of the leather panel is caused to be bonded onto the back of the leather panel surrounded by the folded portion of the leather panel.

Abstract: A ball for a ball game includes an elastic bladder having the form of a spherical hollow body into which compressed air is charged, a reinforced layer formed on a whole surface of the bladder, and a plurality of leather panels bonded onto the reinforced layer directly or through a cover rubber layer, wherein a peripheral edge portion of the leather panel is folded toward an inside and a thickness adjusting member for eliminating a difference in step caused by the folding of the leather panel is caused to be bonded onto the back of the leather panel surrounded by the folded portion of the leather panel.

Abstract: A ball for a ball game includes a bladder made of a spherical elastic air-impermeable material in a hollow spherical shape and filled with air; a spherical flexible shape-maintaining frame body containing the bladder and having openings; and skin panels in a surface skin layer and having edges contacting one another on the frame body, wherein at least the edges of the skin panels are adhered to the frame body.

Abstract: A ball for ball game comprising: a leather skin layer formed by sewing a plurality of leather panels by a thread, the leather skin layer having a spherical shape; and a bladder made of an elastomer having a hollow spherical shape, the bladder being accomodated in the leather skin layer, the bladder being provided with a valve for feeding air into the rubber bladder, the bladder being charged with air through the valve; wherein the thread is made of a self-shrink thread which is subjected to a shrinking treatment after sewing.

Abstract: A method for making a ball for sports comprises providing a round rubber tube, forming a reinforcing layer of a yarn wound about the tube, forming a rubber cover layer formed on the reinforcing layer, and vulcanizing the rubber cover layer to provide a carcass. In the method, the reinforcing layer is formed by winding, in combination, a covered yarn made of a urethane elastomer core thread wound thereabout with a synthetic resin filament or in combination with the synthetic resin filament and a yarn made of a member selected from the group consisting of cotton, polyesters and polyamides. The carcass may be attached with a skin layer made of a natural or artificial leather. Alternatively, the round rubber tube having the reinforcing layer may be attached with a skin layer.

Abstract: A molding apparatus for injection-molding a hemispherical hollow body formed of a thermoplastic elastomer and having a valve formed integrally therewith. The apparatus includes a first mold having a hemispherical convex molding surface, a second mold having a hemispherical concave molding surface larger in size than the convex molding surface. The second mold is superposed on the first mold to form a molding cavity for the hollow body. A first valve mold is removably mounted at the center of the hemispherical convex molding surface of the first mold, for forming the valve and an inside and small-diameter portion of a valve rubber insertion hole of the valve. A second valve mold is removably mounted at the center of the hemispherical concave molding surface, for forming an intermediate and large-diameter portion of the valve rubber insertion hole and an outside and small-diameter portion thereof while forming a cavity for the valve in cooperation with the first valve mold.

Abstract: A ball for ball game, comprising a base body composed of two hemispherical hollow bodies formed by injection-molding a thermoplastic elastomer and bonded together to form a spherical hollow body, said base body containing and sealing compressed air injected therein through an air-injection valve provided at an appropriate portion of one of said two hemispherical hollow bodies, and a plurality of leather panels bonded by means of an adhesive to the surface of said base body, wherein a 10% tensile stress of said thermoplastic elastomer forming said base body ranges from 30 to 190 kg/cm.sup.2. Various properties of said ball such as shock-absorptivity, shape-maintaining property, impact resilience and the like can be set within appropriate ranges.

Abstract: A ball for ball game comprises a rubber hollow spherical bladder, a valve holder fixed to the tube for charging air into the tube, a valve member attached to the valve holder; a fabric layer covering the bladder surface and a leather layer. The fabric layer is composed of a plurality of equilateral quadrilateral pieces sewn together to form a sphere. The equilateral quadrilateral pieces each include two sheets of approximately trapezodial fabric pieces that are sewed together symmetrically at a central seam line. The equilateral quadrilaterla pieces are sewed together such that central seam lines of adjacent equilateral quadrilateral pieces fall at right angles to ech other. The fabric layer gives sphericity, dimensional stability and durability to the ball. The leather layer is adhered to the fabric layer directly or through a rubber based thin intermediate layer.

Abstract: A sound emitting ball has (a) a ball having an airtight bladder with an air injection valve, (b) a housing provided within the ball on the opposite side of the bladder with respect to the valve without interferring with the airtightness of the bladder, (c) a cover for concealing the housing, (d) a detector for detecting an application of external force to the ball, (e) a sound generator for generating a sound signal according to the signal from the detector, (f) a speaker for emitting sound according to the sound signal from the sound generator, and (g) a battery power source. The detector, sound generator, speaker, and battery power source are accommodated in the housing and the sum of the weights of the housing, cover, detector, sound generator, speaker, and battery power source are adjusted to a weight which does not substantially interfere with the impact resilience of the bladder and is substantially the same as the weight of the valve.

Abstract: An athletic ball comprising (a) a ball having an airtight bladder with an air injecting valve, (b) a housing provided with the ball on the opposite side of the valve without interfering the airtightness of the bladder, a detector for detecting an application of external force to the ball, an operation converter for converting the detected impact signal to a numerical information signal, a display for displaying the numerical information and/or for generating a sound according to the numerical information, and a battery power source; the converter, display and battery power source being accommodated in the housing, and the sum of the weights of all of the above elements being adjusted to the weight which does not substantially interfere the impact resilience of the bladder and is substantially the same as that of the valve.