Refrigerated freight containers

Claim 1

A REFRIGERATED FREIGHT CONTAINER COMPRISING AN ELONGATED SUBSTANTIALLY RECTANGULAR BASE FRAME INCLUDING A PAIR OF LONGITUDINALLY EXTENDING SIDE SILLS AND A PAIR OF LATERALLY EXTENDING END SILLS, THE OPPOSITE ENDS OF SAID END SILLS BEING RIGIDLY SECURED TO THE CORRESPONDING OPPOSITE ENDS OF SAID SIDE SILLS, A FIRST LATERALLY EXTENDING INTERMEDIATE SILL ARRANGED WITHIN THE FRONT END PORTION OF SAID BASE FRAME AND LOCATED REARWARDLY OF THE FRONT ONE OF SAID END SILLS, THE OPPOSITE ENDS OF SAID FIRST INTERMEDIATE SILL BEING RIGIDLY SECURED TO THE ADJACENT FRONT PORTIONS OF SAID SIDE SILLS, A FRONT PLATE CARRIED BY THE TOP FRONT END PORTION OF SAID BASE FRAME AND EXTENDING LONGITUDINALLY BETWEEN SAID FRONT END SILL AND SAID FIRST INTERMEDIATE SILL AND RIGIDLY SECURED THERETO AND ALSO EXTENDING LATERALLY BETWEEN THE FRONT PORTIONS OF SAID SIDE SILL AND RIGIDLY SECURED THERETO, THEREBY TO REINFORCE THE FRONT END PORTION OF SAID BASE FRAME, A SECOND LATERALLY EXTENDING INTERMEDIATE SILL ARRANGED WITHIN THE REAR END PORTION OF SAID BASE FRAME AND LOCATED FORWARDLY OF THE REAR ONE OF SAID END SILLS, THE OPPOSITE ENDS OF SAID SECOND INTERMEDIATE SILL BEING RIGIDLY SECURED TO THE ADJACENT REAR PORTIONS OF SAID SIDE SILLS, A REAR PLATE CARRIED BY THE REAR END PORTION OF SAID BASE FRAME AND EXTENDING LONGITUDINALLY BETWEEN SAID REAR END SILL AND SAID SECOND INTERMEDIATE SILL AND RIGIDLY SECURED THERETO AND ALSO EXTENDING LATERALLY BETWEEN THE REAR PORTIONS OF SAID SIDE SILLS AND RIGIDLY SECURED THERETO, THEREBY TO REINFORCE THE REAR END PORTION OF SAID BASE FRAME, AN ELONGATED SUBSTANTIALLY RECTANGULAR FLOOR PANEL OF PREFABRICATED UNITARY RIGID SANDWICH STRUCTURE ARRANGED UPON THE TOP OF SAID FRAME WITH THE LOWER FRONT PORTION OF SAID FLOOR PANEL SUPPORTED UPON THE TOP OF SAID FRONT PLATE AND WITH THE LOWER REAR PORTION OF SAID FLOOR PANEL SUPPORTED UPON THE TOP OF SAID REAR PLATE, THE OPPOSITE SIDES OF SAID FLOOR PANEL BEING SECURELY FASTENED TO SAID SIDE SILLS AND THE OPPOSITE ENDS OF SAID FLOOR PANEL BEING SECURELY FASTENED TO SAID END SILLS, WHEREBY SAID BASE FRAME AND SAID FLOOR PANEL COOPERATE TO PRODUCE A COMPOSITE BASE WITH SAID FLOOR PANEL LENDING GREAT RIGIDITY THERETO, AN UPSTANDING LATERALLY EXTENDING SUBSTANTIALLY RECTANGULAR HEAT-INSULATING BULKHEAD CARRIED BY THE FRONT END PORTION OF SAID FLOOR PANEL AND RIGIDLY SECURED THERETO, SAID BULKHEAD BEING LOCATED APPROXIMATELY ABOVE SAID FIRST INTERMEDIATE SILL, FIRST HEAT-INSULATING STRUCTURE RIGIDLY SECURED TO SAID COMPOSITE BASE AND LOCATED REARWARDLY OF SAID BULKHEAD AND COOPERATING MUTUALLY THEREWITH TO PRODUCE A SUBSTANTIALLY BOX-LIKE BODY DEFINING A LADING COMPARTMENT THEREIN THAT IS DISPOSED ABOVE BOTH THE CENTRAL PORTION AND THE REAR END PORTION OF SAID COMPOSITE BASE, SECOND HEAT-INSULATING STRUCTURE RIGIDLY SECURED TO SAID COMPOSITE BASE AND LOCATED FORWARDLY OF SAID BULKHEAD AND COOPERATING MUTUALLY THEREWITH TO PRODUCE A SUBSTANTIALLY BOX-LIKE HOUSING DEFINING A PLENUM CHAMBER THEREIN THAT IS DISPOSED ABOVE THE FRONT END PORTION OF SAID COMPOSITE BASE, A PLURALITY OF LONGITUDINALLY EXTENDING RIGID STRUCTURAL MEMBERS ARRANGED IN LATERALLY SPACED-APART RELATION AND SECURELY FASTENED TO THE TOP OF SAID FLOOR PANEL, AT THE CENTRAL AND REAR END PORTIONS THEREOF, THEREBY TO REINFORCE THE CORRESPONDING CENTRAL AND REAR END PORTIONS OF SAID COMPOSITE BASE, SAID STRUCTURAL MEMBERS BEING DISPOSED IN SAID LADING COMPARTMENT AND COOPERATING WITH EACH OTHER TO DEFINE IN SAID LADING COMPARTMENT BOTH A LADING-SUPPORTING FLOOR AND A PLURALITY OF LONGITUDINALLY EXTENDING AND LATERALLY SPACED-APART FLOOR FLUES, SAID LADING SUPPORTING FLOOR AND SAID FLOOR FLUES BEING POSITIONED ABOVE THE TOP OF SAID FLOOR PANEL, MEANS FOR CIRCULATING AID FROM SAID PLENUM CHAMBER THROUGH A BOTTOM OPENING PROVIDED IN SAID BULKHHEAD AND THENCE REARWARDLY THROUGH SAID FLOOR FLUES IN SAID LADING COMPARTING AND THEN UPWARDLY AND BACK FORWARDLY THROUGH THE UPPER PORTION OF SAID LADING COMPARTMENT AND ULTIMATELY BACK THROUGH A TOP OPENING PROVIDED IN SAID BULKHEAD AND THUS BACK INTO SAID PLENUM CHAMBER, AND MEANS DISPOSED IN SAID PLENUM CHAMBER FOR COOLING THE AIR THAT IS CIRCULATED THERETHROUGH.