Pneumatic means for production of molded structures

Abstract

Pneumatic means comprising a hollow mandrel or hollow tube having secured around its outer surface along the length thereof according to one embodiment, a flexible open-cell polyurethane foam sleeve and an outer skin formed of a flexible non-permeable plastic such as a vinyl plastic skin adhesively secured to the outer surface of the flexible open-cell foam sleeve, and air passages for communication between the interior of the mandrel and the open-cell foam sleeve, the resulting assembly being positioned in a mold for production of cored structural panels. In operation the tool assembly is placed under pressure and expanded to force the plastic skin of the assembly outwardly during pouring and setting of the construction material, e.g., a cement or cement-polymer composition in a mold, and after setting thereof the tool assembly is subjected to reduced pressure or a vacuum to withdraw the plastic skin from the set composition, e.g., in the form of a molded panel, to facilitate removal of the tool from the molded panel, thereby forming a cored construction material or panel. Also included as a feature, pneumatic means in the form of a bellows arrangement comprising an external flexible, e.g., rubber, corrugated member, and in the interior of such corrugated member a permeable open-cell, e.g., polyurethane, foam, and tensioning means, said bellows being inflatable for applying pressure to force a contact, e.g., honeycomb, member mounted on the bellows, against an outer surface of a casting composition in a mold, to form an outer surface for a structural molded panel, and which bellows can be deflated to facilitate removal of the pneumatic tool and associated members from the mold following setting of the panel construction. Also included, means providing a combination or arrangement of a plurality of both said mandrel and bellows assemblies for provision of a cored molded structural panel containing outer surfaces of a predetermined, e.g., smooth or textured, configuration.

Dependencies are inferred from the claim text.