royle

Claim 1

A BEARING FOR SUPPORTING A MOVABLE MEMBER IN A PREDETERMINED POSITION WITHIN AN ENCLOSING STRUCTURE, CLEAR OF THE WALLS OF THAT STRUCTURE, BY MEANS OF FLUID UNDER PRESSURE, COMPRISING A PLURALITY OF FLUID SUPPLY SYSTEMS FORMED IN THE STRUCTURE, EACH SYSTEM COMPRISING A MAIN FLUID SUPPLY ORIFICE AND A PILOT FLUID SUPPLY ORIFICE, THE SYSTEMS BEING SO SUPPORTED THAT WHEN THE MEMBER MOVES AWAY FROM ONE ORIFICE OF ONE SYSTEM IT MOVES TOWARDS THE CORRESPONDING ORIFICE IN ANOTHER SYSTEM, MEANS FOR PERMITTING THE ESCAPE, FROM THE CLEARANCE SPACE BETWEEN THE MOVABLE MEMBER AND THE STRUCTURE, OF FLUID SUPPLIED TO THE MAIN AND PILOT ORIFICES OF THE BEARING, IN WHICH THE FLUID IN ONE OF THE MAIN ORIFICES IS MAINTAINED AT A FIXED PRESSURE, THE OTHER MAIN ORIFICES BEING EACH RELATED WITH THEIR CORRESPONDING PILOT ORIFICE SO THAT AS THE CLEARANCE BETWEEN A PILOT ORIFICE AND THE MOVABLE MEMBER RISES OR FALLS THE FLUID PRESSURE AT THE CORRESPONDING MAIN ORIFICE VARIES IN THE OPPOSITE SENSE, IN WHICH THERE IS A DEVICE FOR DERIVING THE MEAN PRESSURE OF ALL THE PRESSURES ACTING AT THE INDIVIDUAL PILOT ORIFICES AND CONTROL VALVES ARE FITTED IN THE FLUID LINES LEADING TO SUCH OF THE MAIN ORIFICES AS ARE MAINTAINED AT VARIABLE PRESSURE, EACH OF SAID CONTROL VALVES HAVING OBTURATING MEMBERS URGED TO MOVE IN ONE DIRECTION BY FLUID AT THE SAID MEAN PRESSURE AND IN THE OTHER DIRECTION BY FLUID AT THE PRESSURE OF THE FLUID IN THE CORRESPONDING PILOT ORIFICE.