초록 ▼

Composite bowling pins and baseball bats are formed with foamed, cured-in place plastic bodies securely adhered to a central aluminum core by a somewhat thermoplastic adhesive coating. The exothermic reaction attendant to curing the plastic so softens the adhesive coating that it does not interfere

Composite bowling pins and baseball bats are formed with foamed, cured-in place plastic bodies securely adhered to a central aluminum core by a somewhat thermoplastic adhesive coating. The exothermic reaction attendant to curing the plastic so softens the adhesive coating that it does not interfere with shrinkage of the plastic body relative to the core. This minimizes stress concentrations in the composite construction which otherwise tend to lead to cracking in use.

대표청구항 ▼

The method of making a molded composite baseball bat, bowling pin or like article having a body of cured-in-place foam plastic of a type which has an exothermic reaction and shrinks on curing comprising the steps of coating an elongated aluminum core with an adhesive of the type which at least partl

The method of making a molded composite baseball bat, bowling pin or like article having a body of cured-in-place foam plastic of a type which has an exothermic reaction and shrinks on curing comprising the steps of coating an elongated aluminum core with an adhesive of the type which at least partly softens at the temperature of such exothermic reaction and which at room temperature will securely bond foamed plastic to said core causing said coating to dry, mounting said coated core within a mold, foaming plastic material thereabout within the mold and causing such exothermic reaction, softening the dry adhesive coating on the core with the heat of such exothermic reaction, permitting the foamed plastic to shrink and draw together slippingly along the softened adhesive coating on the core, and thereafter permitting the adhesive coating to harden during cooling of said foamed plastic, whereby to minimize stresses which would otherwise accompany resistance of the core to the shrinking of the plastic.