Balancing or stabilizing mechanism for vertically movable tank roofs

Claim 1

IN A TANK HAVING ITS UPPER END CLOSED BY A DISCLIKE ROOF THAT IS VERTICALLY MOVABLE WITH RESPECT TO THE TANK IN ORDER TO VARY THE INTERNAL VOLUME OF THE TANK BENEATH THE ROOF, THE COMBINATION COMPRISING, AN UPSTANDING SUBSTANTIALLY RIDID VERTICAL GUIDE POST FIXED AT ITS LOWER END AT THE CENTER OF THE TANK AND HAVING ITS UPPER END PORTION EXTENDING THROUGH AN OPENING IN THE CENTER OF THE ROOF, ROLLER MEANS FOR GUIDING SAID ROOF UPON SAID POST FOR ARTICULATE TILTING MOVEMENTS WITH RESPECT THERETO AND ALSO FOR GUIDED VERTICAL MOVEMENTS ALONG SAID POST, SAID ROLLER MEANS BEING SO CONSTRUCTED AND ARRANGED AS FREELY TO ACCOMMODATE TILTING MOVEMENT OF SAID ROOF WITH RESPECT TO SAID POST AND WITH RESPECT TO THE HORIZONTAL WHEN AN UNBALANCING OFF-CENTER LOAD IS APPLIED TO SAID ROOF, AN UPWARDLY EXTENDING HOUSING HERMETICALLY COVERING SAID OPENING IN SAID ROOF AND CONTAINING SAID ROLLER MEANS, SAID UPPER PORTION OF SAID POST EXTENDING UPWARDLY INTO SAID HOUSING, AND AN ANNULAR BALANCING WEIGHT FOR SAID ROOF ENCOMPASSING SAID POST AND ARRANGED FOR GUIDED VERTICAL SLIDING MOVEMENTS THEREON, SAID ANNULAR BALANCING WEIGHT BEING OF SUBSTANTIAL MASS AND BEING SUSPENDED BENEATH SAID ROOF SOLELY FROM THE PERIPHERAL PORTION THEREOF BY A PLURALITY OF SUBSTANTIALLY EQUALLY SPACED FLEXIBLE SUSPENSION MEMBERS HAVING THEIR RESPECTIVE UPPER ENDS SECURED TO SAID PERIPHERAL PORTION OF SAID ROOF AT CIRCUMFERENTIALLY SPACED LOCATIONS THEREON AND HAVING THEIR LOWER ENDS SECURED TO SAID WEIGHT, THE MASS OF SAID BALANCING WEIGHT TENDING TO MAINTAIN SAID ROOF IN A HORIZONTAL ATTITUDE AND CAUSING SAID ROOF TO RETURN TO SAID HORIZONTAL ATTITUDE WHEN AN UNBALANCING OFF-CENTER LOAD IS REMOVED FROM SAID ROOF.