Method for fabricating solid tire having polyurethane foam core

A method for fabricating a solid tire having a tire casing filled with a microcellular polyurethane foam forming a core comprising the steps of:

• installing a jig on the tire casing, said jig simulating the wheel hub with which the tire is to be used, said jig having two similar halves which are placed on opposite sides of the casing flush against each other and against the opposite outer surfaces of said casing, said jig being centered on the casing, the halves thereof being clamped flush against each other and in tight abutment against the opposite outer surfaces of the casing, said jig having a fill hole in one of the halves thereof which provides fluid communications between the interior of the casing and the exterior of the jig,
• forming a plurality of vent holes in a circle along the high point on the outer casing wall against which said one of the halves of said jib abuts,
• supporting the tire in a substantially horizontal position with the vent holes facing upwardly,
• filling said casing through said fill hole with an amount of a liquid flexible microcellular polyurethane foam forming mixture composed of polyol and isocyanate such that said polyurethane foam, expanding in response to the chemical reaction of the mixture of said polyol and isocyanate, will completely fill said casing,
• plugging said fill hole to contain the polyurethane foam within the casing, and
• removing said jig from said casing a predetermined time period after the casing has been filled, while the polyurethane foam is still expanding, such that the polyurethane foam expands both towards the center of the casing and outwardly tightly against the casing so that it any remaining air is vented out through the vent holes to avoid the formation of air pockets in the casing.