Method for making an integrated reinforced plastic unit

Claim 1

THE METHOD OF THERMOFORMING AN INTEGRATED PLASTIC UNIT WHICH COMPRISES PROVIDING A MOLD WITH SPACERS HAVING NOTCHES AT THE UPPER END THROUGHOUT THE FACE OF THE MOLD WITH THE SPACERS EXTENDING IN A GENERALLY STRAIGHT LINE IN ONE DIRECTION ON THE MOLD AND IN A GENERALLY STRAIGHT LINE IN A SECOND DIRECTION ON THE MOLD TO THE FREE UPPER END OF THE SPACERS AND THE FACE OF THE MOLD TO THE FREE UPPER END OF THE SPACERS AND THE NOTCHES IN THE SPACERS BEING A SHORT DISTANCE ABOVE THE SURFACE OF THE MOLD AND FILLET MEMBERS DISPOSED BETWEEN THE SPACERS WITH SAID MEMBERS TAPERED CORRESPONDINGLY TO THE TAPER OF THE SPACERS, PLACING A FIRST SET OF METAL REINFORCING MEMBERS IN THE NOTCHES OF THE FIRST NAMED SPACERS AND A SECOND SET OF REINFORCING MEMBERS IN THE NOTCHES OF THE SECOND NAMED SPACERS AND ACROSS THE FIRST NAMED REINFORCING MEMBERS WITH SAID REINFORCING MEMBERS CRISSCROSSING AT THE LOCATION OF THE SPACERS AND FILLET MEMBERS, HEATING A SINGLE SHEET OF POLYETHYLENE THERMOPLASTIC MATERIAL TO A TEMPERATURE WHEREBY THE SHEET AFTER HEATING IS IN A PLIABLE CONDITION SO THAT IT WILL READILY FLOW WHEN PRESSURE IS APPLIED TO IT, THEN PLACING THE SINGLE SHEET OF THE PREHEATED POLYETHYLENE THERMOPLASTIC MATERIAL OVER THE REINFORCING MEMBERS, THE SHEET BEING OF A SLIGHTLY GREATER SIZE THAN THE MOLD, SEALING THE ENDS OF THE SHEET TO THE MOLD, THEREAFTER DRAWING A VACUUM THROUGH HOLES IN THE MOLD TO FORCE THE PLASTIC SHEET TOWARD THE MOLD, CONTINUING TO APPLY THE VACUUM TO THEREBY EFFECT FLOW OF THE THERMOPLASTIC MATERIAL AROUND AND UNDERNEATH THE REINFORCING FORMING MEMBERS TO THEREBY ENCAPSULATE SAID FORMING MEMBERS AND MELDING THE THERMOPLASTIC MATERIAL INTO A SINGLE SOLID RIB EXTENDING UNDER AND FROM EACH REINFORCING MEMBER UNINTERRUPTED BY ANY HAIRLINE CREVICES, FURTHER CONTINUING TO APPLY THE VACUUM TO FLOW THE THERMOPLASTIC MATERIAL OVER THE MOLD TO FORM A FLAT SURFACE EXTENDING IN A DIRECTION AT GENERALLY RIGHT ANGLES TO SAID RIBS WHILE SIMULTANEOUSLY DAMMING THE FLOW OF SAID MATERIAL BY SAID SPACERS AND FILLET MEMBERS TO PREVENT THINNING AND CONSEQUENT TEARING OF THE PLASTIC SHEET AT THE CROSS OVER AREAS OF THE METAL REINFORCING MEMBERS, AND THEN COOLING SAID INTEGRATED PLASTIC UNIT.

Claim 2

THE METHOD OF THERMOFORMING AN INTEGRATED PLASTIC UNIT WHICH COMPRISES PROVIDING A MOLD WITH SPACERS HAVING NOTCHES AT THE UPPER END THROUGHOUT THE FACE OF THE MOLD WITH THE SPACERS EXTENDING IN A GENERALLY STRAIGHT LINE IN ONE DIRECTION ON THE MOLD AND IN A GENERALLY STRAIGHT LINE IN A SECOND DIRECTION ON THE MOLD TO THE FREE UPPER END OF THE SPACERS AND THE FACE OF THE MOLD TO THE FREE UPPER END OF THE SPACERS AND THE NOTCHES IN THE SPACERS BEING A SHORT DISTANCE ABOVE THE SURFACE OF THE MOLD AND FILLET MEMBERS DISPOSED BETWEEN THE SPACERS WITH SAID MEMBERS TAPERED CORRESPONDINGLY TO THE TAPER OF THE SPACERS, PLACING A FIRST SET OF METAL REINFORCING MEMBERS IN THE NOTCHES OF THE FIRST NAMED SPACERS AND A SECOND SET OF REINFORCING MEMBERS IN THE NOTCHES OF THE SECOND NAMED SPACERS AND ACROSS THE FIRST NAMED REINFORCING MEMBERS WITH SAID REINFORCING MEMBERS CRISSCROSSING AT THE LOCATION OF THE SPACERS AND FILLET MEMBERS, HEATING A SINGLE SHEET OF POLYETHYLENE THERMOPLASTIC MATERIAL TO A TEMPERATURE WHEREBY THE SHEET AFTER HEATING IS IN A PLIABLE CONDITION SO THAT IT WILL READILY FLOW WHEN PRESSURE IS APPLIED TO IT, THEN PLACING THE SINGLE SHEET OF THE PREHEATED POLYETHYLENE THERMOPLASTIC MATERIAL OVER THE REINFORCING MEMBERS, THE SHEET BEING OF A SLIGHTLY GREATER SIZE THAN THE MOLD, SEALING THE ENDS OF THE SHEET TO THE MOLD, THEREAFTER DRAWING A VACUUM THROUGH HOLES IN THE MOLD TO FORCE THE PLASTIC SHEET TOWARD THE MOLD, CONTINUING TO APPLY THE VACUUM TO THEREBY EFFECT FLOW OF THE THERMOPLASTIC MATERIAL AROUND AND UNDERNEATH THE REINFORCING FORMING MEMBERS TO THEREBY ENCAPSULATE SAID FORMING MEMBERS AND MELDING THE THERMOPLASTIC MATERIAL INTO A SINGLE SOLID RIB EXTENDING UNDER AND FROM EACH REINFORCING MEMBER UNINTERRUPTED BY ANY HAIRLINE CREVICES, FURTHER CONTINUING TO APPLY THE VACUUM TO FLOW THE THERMOPLASTIC MATERIAL OVER THE MOLD TO FORM A FLAT SURFACE EXTENDING IN A DIRECTION AT GENERALLY RIGHT ANGLES TO SAID RIBS WHILE SIMULTANEOUSLY DAMMING THE FLOW OF SAID MATERIAL BY SAID SPACERS AND FILLET MEMBERS TO PREVENT THINNING AND CONSEQUENT TEARING OF THE PLASTIC SHEET AT THE CROSS OVER AREAS OF THE METAL REINFORCING MEMBERS, AND THEN COOLING SAID INTEGRATED PLASTIC UNIT.

Claim 3

The method of making a loading pallet, which comprises providing a mold having spacer members throughout the face of the mold with the spacer members extending in a generally straight line in one direction on the mold and in a generally straight line in a second direction on the mold and with the spacer members tapering from the face of the mold substantially to the top of each member with said top being a short distance above the face of the mold, and said mold having leg formers, assembling metal reinforcing members over said mold a slight distance above the face of the mold and crisscrossed at the location of said spacers, heating a single sheet of thermoplastic material to a temperature whereby the sheet after heating is in a pliable condition so that it will readily flow when pressure is applied to it, then placing the single sheet of the preheated thermoplastic material over the reinforcing members, the plastic sheet being of a slightly greater size than the mold, sealing the ends of the sheet to the mold, thereafter applying pressure to the plastic sheet to force the sheet towards the mold and over the leg formers, continuing to apply pressure to thereby effect flow of the sheet around and underneath the reinforcing forming members and melding the thermoplastic sheet into a single solid rib extending under and from each reinforcing forming member uninterrupted by any hairline crevices, further continuing to apply the pressure to flow the thermoplastic sheet over the mold to form a flat surface extending in a direction at generally right angles to said ribs while simultaneously damming the flow of the material by said spacer members to prevent thinning and consequent tearing of the material at the crossover areas of the metal reinforcing members, and thereafter cooling the assembled pallet.

Claim 4

The method of making a loading pallet, which comprises providing a mold having spacer members throughout the face of the mold with the spacer members extending in a generally straight line in one direction on the mold and in a generally straight line in a second direction on the mold and with the spacer members tapering from the face of the mold substantially to the top of each member with said top being a short distance above the face of the mold, and said mold having leg formers, assembling metal reinforcing members over said mold a slight distance above the face of the mold and crisscrossed at the location of said spacers, heating a single sheet of thermoplastic material to a temperature whereby the sheet after heating is in a pliable condition so that it will readily flow when pressure is applied to it, then placing the single sheet of the preheated thermoplastic material over the reinforcing members, the plastic sheet being of a slightly greater size than the mold, sealing the ends of the sheet to the mold, thereafter applying pressure to the plastic sheet to force the sheet towards the mold and over the leg formers, continuing to apply pressure to thereby effect flow of the sheet around and underneath the reinforcing forming members and melding the thermoplastic sheet into a single solid rib extending under and from each reinforcing forming member uninterrupted by any hairline crevices, further continuing to apply the pressure to flow the thermoplastic sheet over the mold to form a flat surface extending in a direction at generally right angles to said ribs while simultaneously damming the flow of the material by said spacer members to prevent thinning and consequent tearing of the material at the crossover areas of the metal reinforcing members, and thereafter cooling the assembled pallet.