Door closure and operating means

Claim 1

DOOR OPERATING MEANS FOR A CYLINDRICAL DRUM OF THE TYPE HAVING A DOOR OPENING, SAID OPENING HAVING TOP, BOTTOM AND SIDE EDGES, AND A DOOR FOR SAID OPENING COMPRISING AN UPPER PANEL AND A LOWER PANEL, THE UPPER PANEL BEING HINGED TO THE DRUM WALL ALONG THE TOP EDGE OF SAID OPENING TO PROVIDE A FIRST AXIS OF SWING, AND THE LOWER PANEL BEING HINGED TO THE UPPER PANEL ALONG A SECOND AXIS OF SWING, BOTH SAID AXES BEING PARALLEL TO EACH OTHER WHEREBY TO PERMIT SAID PANELS TO BE SWUNG UPWARDLY AND INWARDLY ON SAID FIRST AXIS, AND SIMULTANEOUSLY TO BE JACKNIFED TOWARDS MUTUAL OVERLAP BY MOVEMENT OF SAID LOWER PANEL AROUND SAID SECOND AXIS SO AS TO CLEAR SAID DOOR OPENING FOR LOADING OR UNLOADING, A RESILIENT SEALING STRIP EXTENDING ALONG THE TWO SIDE EDGES AND THE BOTTOM EDGE OF SAID OPENING AND ADAPTED TO BE CONTACTED RESPECTIVELY BY ADJACENT SIDE EDGES OF SAID DOOR PANELS AND BY THE BOTTOM EDGE OF SAID LOWER PANEL WHEN SAID DOOR APPROACHES CLOSED POSITIONS, SAID DOOR IN THE LATTER POSITION CONSTITUTING A TOGGLE SYSTEM WHERIN SAID SECOND AXIS IS THE CENTER PIVOT, AND IS DISPOSED RADIALLY OUTWARDLY OF A PLANE COMMON TO SAID FIRST AXIS AND THE SEALING STRIP ALONG THE BOTTOM OF SAID OPENING, AND OPERATING MEANS FOR SAID DOOR COMPRISING A FIRST FLUID POWER MOTOR AND A SECOND FLUID POWER MOTOR, A PISTON IN SAID FIRST FLUID MOTOR, A FIRST LINKAGE MEANS CONNECTING SAID PISTON WITH SAID LOWER PANEL WHEREBY WHEN SAID FIRST MOTOR IS ENERGIZED SAID DOOR MOVES BETWEEN OPEN AND AN INITIAL CLOSED POSITION, IN WHICH POSITION THE SIDE EDGES AND BOTTOM EDGE OF SAID DOOR ESTABLISH INITIAL CONTACT WITH THE RESPECTIVE SIDE SEALING STRIPS AND THE BOTTOM SEALING STRIP, A PISTON IN SAID SECOND FLUID POWER MOTOR, A PISTON ROD EXTENDING OUTWARDLY THEREFROM, A SWINGABLE LEVER PIVOTED AT ONE POINT TO SAID PISTON ROD, A COOPERATING MEMBER ON SAID DOOR ADJACENT TO SAID SECOND AXIS OF SWING, SAID COOPERATING MEMBER BEING ADAPTED TO BE OPERATIVELY ENGAGED BY SAID SWINGABLE LEVER WHEN SAID DOOR IS IN INITIAL CLOSED POSITION AND SAID SECOND MOTOR IS ENERGIZED, WHEREBY, UPON ENERGIZATION OF SAID SECOND MOTOR SAID LEVER ENGAGES SAID COOPERATING MEMBER TO EXTEND SAID TOGGLE SYSTEM AND APPLY TIGHTLY SEALING PRESSURE OF THE DOOR EDGES ON THE BOTTOM AND SIDE SEALING MEMBERS, SAID LOWER EDGE OF SAID SECOND PANEL BEING RELATIVELY NARROW WHEREBY TO READILY INDENT SAID RESILIENT SEALING STRIP AND AUGMENT THE SEALING ACTION.