Mueller-perry Co., Inc.

Desoto, Inc.

Alvin W Mueller

Robert E Ansel

Robert J Williams

Bowling pins formed by molding a plastic shell about a foamed plastic core have not heretofore come into practical use because of inability to withstand shocks in service, resulting in separation of the shell from the core. According to the present invention, a foamed thermoset (non-melting) copolymer is employed for casting the core. Thereafter, before casting a plastic shell thereabout, the core surface area is substantially increased by simply removing the core surface skin, thereby opening the outermost thermoset core cells for filling by the shell material.

Method of making a bowling pin having expanded copolymer core

A method for forming a plastic composite bowling pin includes removing the surface skin of a foam core, mounting a plastic base ring on such core, and molding a relatively thick elastomer shell around the prepared core and the base ring so that the hardening of the shell interlocks the shell, core and base ring. A pin made by this method is easily refurbished by removing the base ring and part of the shell and re-molding the surface of the shell.

Bowling pin with interlocking shell to form core and base

A composite baseball bat has a unique tapered aluminum spar encased in polyurethane foam. The tapered spar is formed by swaging, starting with an aluminum tube whose outer diameter and wall thickness are those for the barrel section of the bat. A tapering portion is swaged to a decreasing outer diameter and increasing wall thickness, which is then constant over the handle portion of the bat. This construction yields far greater stiffness and freedom from objectionable vibrations.

Composite baseball bat having swaged spar and plastic foam covering

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.

Method for making a stress-relieved composite foamed resin baseball bat

A composite molded baseball bat is provided using a tubular, high yield strength aluminum core surrounded by a foam plastic body having a density of from 30-50 pounds per cubic foot and an integral outer skin. The tubular aluminum core has an outside diameter of from three-quarters to 1 inch and a wall thickness of from 0.062 to 0.125 inch.

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St. Louis, MO, United States of America

Alvin W Mueller