Production of magnetic sound tape

Claim 1

IN THE METHOD OF PRODUCING MAGNETIC SOUND-RECORDING AND SOUND-REPRODUCING TAPE BY PASSING A RELATIVELY LONG AND NARROW TAPE BASE HAVING AN OBSTRUCTION THEREON SUCCESSIVELY THROUGH A COATING ZONE AND A DRYING ZONE, ONE SIDE OF THE TAPE BASE BEING COATED WITH A LAYER OF FREE-FLOWING MAGNETIC MATERIAL SUSPENDED IN A LIQUID VEHICLE WHILE MOVING THROUGH THE COATING ZONE AND THE COATING BEING DRIED WHILE MOVING THROUGH THE DRYING ZONE, THE IMPROVEMENT WHICH COMPRISES PROVIDING AND MAINTAINING IN THE COATING ZONE A GAP OF PREDETERMINED MINIMUM UNIFORM HEIGHT WIDER THAN THE THICKNESS OF THE TAPE BASE BETWEEN A BOTTOM SUPPORT FOR THE TAPE BASE AND A SUPERPOSED TRANSVERSE LIQUID BODY OF THE FREEFLOWING MAGNETIC MATERIAL, MOVING THE TAPE BASE CONTAINING THE OBSTRUCTION THROUGH THE GAP WITH ITS BOTTOM SIDE IN SURFACE TO SURFACE CONTACT WITH THE TOP OF THE SUPPORT IN A GENERALLY HORIZONTAL DIRECTION AND ITS TOP SIDE NORMALLY OUT OF CONTACT WITH AND AT A PREDETERMINED MINIMUM DISTANCE BELOW THE LIQUID BODY OF MAGNETIC MATERIAL TO ASSURE A COATING OF PREDETERMINED THICKNESS ON THE TOP SIDE OF THE TAPE BASE, INCREASING MOMENTARILY THE HEIGHT OF THE GAP IN RESPONSE TO THE OBSTRUCTION ON THE TAPE BASE AS THE OBSTRUCTION ENTERS THE GAP SO THAT THE OBSTRUCTION MAY PASS BETWEEN THE SUPPORT AND THE LIQUID BODY OF MAGNETIC MATERIAL WITHOUT SUBSTANTIAL PHYSICAL DAMAGE TO THE TAPE BASE, RESTORING THE GAP TO ITS FORMER PREDETERMINED MINIMUM UNIFORM HEIGHT AS SOON AS THE OBSTRUCTION PASSES THERETHROUGH, DEPOSITING FROM THE LIQUID BODY A LAYER OF THE MAGNETIC MATERIAL OF PREDETERMINED THICKNESS TRANSVERSELY ACROSS THE TOP SIDE OF THE MOVING TAPE BASE, THE AMOUNT OF INCREASE IN THE HEIGHT OF THE GAP BEING NO MORE THAN THAT NECESSARY TO PERMIT PASSAGE OF THE OBSTRUCTION THROUGH THE GAP SO THAT THE THICKNESS OF THE COATING ADJACENT EACH SIDE OF THE OBSTRUCTION, IN THE DIRECTION OF TRAVEL OF THE TAPE BASE, IS OF THE SAME UNIFORM THICKNESS AS THE COATING ON THE REMAINDER OF THE TAPE BASE, AND PASSING THE TAPE BASE THUS COATIED WITH MAGNETIC MATERIAL TO AND THROUGH THE DRYING ZONE.