Manufacture of plastic articles having spaced shells with reinforced foam filling

Claim 1

THE PROCESS OF MANUFACTURING RIGID SELF-SUSTAINING STRUCTURES OF PLASTIC HAVING OUTER SHELL LAYERS OF HARD SETTING DENSE PLASTIC REINFORCED WITH FIBER REINFORCEMENT AND A CENTRAL BODY OF HARD SETTING LIGHT FOAM PLASTIC REINFORCED AGAINST FAILURE FROM SHEAR STRAINS WHICH COMPRISES THE FOLLOWING STEPS; APPLYING SHELL COATINGS OF GLASS FIBER COMBINED WITH UNCURED PLASTIC TO MOLD SURFACES OF IRREGULAR SHAPE, APPLYING DEFORMABLE BODIES COATED WITH UNCURED PLASTIC COMPATIBLE WITH THE PLASTIC OF THE MOLD COATING AT SPACED INTERVALS TO THE SHELL COATING ON AT LEAST ONE OF THE MOLD SURFACES SO AS TO FORM ISLANDS HAVING UNOBSTRUCTED PASSAGEWAYS BETWEEN THEM, THE ISLANDS BEING THICKER THAN THE SPACE BETWEEN THE SHELL COATINGS WHEN THE MOLD IS CLOSED, INTRODUCING A FOAM FORMING PLASTIC MIXTURE, CLOSING THE MOLD AND AT THE SAME TIME COMPRESSING AND DEFORMING THE ISLANDS TO SUCH EXTENT AS MAY BE NECESSARY TO PERMIT THE MOLD TO CLOSE, PERMITTING THE FOAM FORMING MIXTURE TO EXPAND AND FILL THE SPACES BETWEEN THE MOLD PARTS AND AROUND THE SPACED DEFORMABLE ISLANDS, ALLOWING THE SHELL COATINGS, ISLANDS, AND PLASTIC FOAM TO CURE TO A RIGID SUBSTANTIALLY INTEGRATED MASS, AND REMOVING THE FINISHED ARTICLE FROM THE MOLD.