Method of making tennis ball with a single core and cover bonding cure

A method of making internally pressurized tennis balls comprising the steps of:

• premolding a pair of rubber, hemispherical core halves, one of which is provided with an integrally formed one-way air valve therein;
• removing any rubber flashing present from the premolding step on said halves and exteriorly grinding exterior surfaces of said core halves to facilitate subsequent cementing of fabric pieces thereto;
• applying a first suitable curable cement to mating core halves end faces and allowing the same to dry to a tacky, uncured state;
• assembling the two core halves to one another with a mass of air therein at substantially atmospheric pressure and holding them in a subassembly thereof by the tackiness of the first cement;
• dipping the core subassembly in a suitable, second fabric adhesive curable cement and letting the same dry to a tacky, uncured state;
• providing a pair of fabric pieces of generally figure eight configuration and coating lateral edges thereof with a suitable, curable third cement and allowing the same to dry to a tacky uncured state;
• assembling the fabric pieces about the ball core subassembly to provide a ball assembly of core parts and fabric pieces with the first, second and third uncured cements holding the core halves to one another, the fabric pieces to the core and the fabric edges to one another, respectively, to provide an uncured and internally unpressurized ball assembly;
• placing the ball assembly within a suitable heat providing mold and applying heat through said mold to said cements of said ball assembly to cure the same and concurrently bond said core halves to one another, said fabric pieces to said core halves and said fabric pieces to one another in a single bonding step during which the air pressure within said assembly is that due only to the affect thereon of said heat on said mass of air therein;
• and
• subsequently subjecting said bonded ball assembly to an above atmospheric external pressure of a pressurizing medium such as air to introduce such medium into the bonded ball assembly core to thereby provide an internally pressurized ball.

A method of making internally pressurized tennis balls and the like which include an assembly of core halves and fabric cover pieces secured together by cured adhesive comprising the steps of:

• providing a pair of core halves, one of which has a one-way air valve therein for subsequently injecting air into the assembled core, and holding said halves together in a subassembly thereof by the tackiness of a suitable cement applied to edge surfaces of the halves which abut when said halves are provided in such subassembly, said subassembly having a mass of air therein at substantially atmospheric pressure;
• applying a fabric cover of fabric pieces about said core subassembly to provide a assembly of core halves and cover of fabric pieces with a suitable curable cement between said piece and said core and between each other and holding said assembly in a prefinished state by the tackiness of the step uncured cements;
• curing the cements of said assembly concurrently in a single step to complete a bonding of said core halves together, said fabric pieces to said core and said fabric pieces to each other in a single curing step, said curing step comprising the application of heat only to said assemblies without the application of additional internal or external pressure, the air pressure within said assembly during said curing being only that due to the affect of said heat on said mass of air therein;
• and
• thereafter introducing a pressurizing medium such as air into said assembly core through said one-way valve.