Air-cushioned tape guide

Claim 1

IN A TAPE TRANSPORT SYSTEM WHEREIN A TRAVELLING TAPE PASSES AROUND A CYLINDRICALLY CURVED MEANS TO FORM A LOOP WITH AN INGOING LEG AND AN OUTGOING LEG WITH FIRST MEANS POSITIVELY GRIPPING THE TAPE TO FEED THE TAPE TO THE INGOING LEG AT A GIVEN RATE AND SECOND MEANS POSITIVELY GRIPPING THE TAPE TO WITHDRAW THE TAPE FROM THE OUTGOING LEG AT A GIVEN HIGHER RATE TO COOPERATE WITH THE FIRST MEANS TO MAINTAIN THE LOOP UNDER PREDETERMINED CONSTANT TENSION WITH TRANSDUCER MEANS COOPERATING WITH THE TAPE ADJACENT AT LEAST ONE LEG OF THE LOOP, WHEREIN A CLOSEDLOOP SERVO-MECHANISM REGULATES THE SPEED OF SAID FIRST AND SECOND MEANS TO KEEP THE SPEED OF THE TAPE IN THE LOOP CONSTANT WITHIN A SMALL RANGE OF DEVIATION AND WHEREIN SAID TRANSDUCER MEANS INCLUDES A READING HEAD THAT IS INCLUDED IN THE CLOSED-LOOP SERVOMECHANISM, THE IMPROVEMENT TO ENABLE THE SYSTEM TO DRIVE THE TAPE IN A STABLE MANNER WITH THE RANGE OF DEVIATION REDUCED TO A FEW MICROINCHES, COMPRISING: SAID CYLINDRICALLY CURVED MEANS BEING A STATIONARY HOLLOW MEMBER HAVING A CURVED WALL ITS EXTERIOR TO GUIDE THE TAPE, THE CURVED WALL BEING POROUS AND BEING FORMED FROM SOLID PARTICLES TO PROVIDE NUMEROUS CLOSELY SPACED EXCEEDINGLY SMALL TORTUOUS FLOW PASSAGES THERETHROUGH; MEANS FOR PROVIDING COMPRESSED GASEOUS FLUID; AND MEANS OPERATIVELY COUPLED TO THE LAST MENTIONED MEANS TO SUPPLY THE INTERIOR OF THE HOLLOW MEMBER WITH THE COMPRESSED GASEOUS FLUID FOR FLOW THROUGH THE TORTUOUS FLOW PASSAGES TO THE CURVED WALL TO MAINTAIN A CUSHION OF THE GASEOUS FLUID BETWEEN THE TRAVELING TAPE AND THE CURVED WALL AND TO MAINTAIN THE TAPE OUT OF CONTACT WITH THE CURVED WALL IN OPPOSITION TO THE TENSION OF THE TAPE.