Tank lifting mechanism

Claim 1

AN ARTICLE LIFTING MECHANISM COMPRISING A FRAME, MEANS MOVING SAID FRAME TO A POSITION SPACED FROM AN ARTICLE TO BE LIFTED, A PLURALITY OF GRIPPER HEAD ASSEMBLIES CARRIED ON SAID FRAME, EACH GRIPPER HEAD ASSEMBLY COMPRISING A CONTROLLING CYLINDER HAVING A PISTON THEREIN AND A GRIPPER HEAD MOUNTED ON THE PISTON, EACH OF SAID GRIPPER HEADS HAVING A SUCTION GROOVE FROM WHICH AIR IS TO BE EVACUATED, MEANS ON SAID FRAME SUPPLYING FLUID TO SAID CONTROLLING CYLINDERS FOR INDEPENDENTLY MOVING EACH PISTON AND ITS RESPECTIVE GRIPPER HEAD RELATIVE TO THE FRAME AND WITH THE SAME FORCE AGAINST SAID ARTICLE TO BE LIFTED AS THE FRAME IS MAINTAINED IN A STATIONARY POSITION, THE MOVEMENT OF EACH GRIPPER HEAD BEING STOPPED BY ENGAGEMENT WITH SAID ARTICLE SUCH THAT EACH GRIPPER HEAD CONTACTS AND ENGAGES THE ARTICLES WITH THE SAME FORCE IRRESPECTIVE THAT SOME GRIPPER HEADS MAY HAVE MOVED FURTHER THAN OTHERS, AND MEANS ON SAID FRAME FOR EVACUATING SUCH SUCTION GROOVE TO CREATE A REDUCED PRESSURE IN SAID GRIPPER HEADS TO PERMIT EACH OF THE HEADS TO GRIP THE ARTICLE WITH A SUBSTANTIALLY EQUAL FORCE TO REDUCE THE TENDENCY OF THE GRIPPER HEAD TO DISTORT AND OTHERWISE DAMAGE THE ARTICLE.