Magnetic recording and playback systems

Claim 1

A MAGNETIC TAPE RECORDING AND PLAY-BACK DEVICE COMPRISING A SUPPLY-REEL; A TAKE-UP REEL; A ROTATABLE CYLINDRICAL TAPE-GUIDE ARRANGED IN SUCH A WAY BETWEEN SAID SUPPLY REEL AND SAID TAKE-UP REEL AS TO BE ENGAGED ALONG A PREDETERMINED ANGLE BY TAPE RUNNING FROM SAID SUPPLY-REEL OVER SAID TAPE-GUIDE TO SAID TAKE-UP REEL; AN ELECTROMAGNETIC TRANSDUCER ROTATABLE ABOUT AN AXIS PARALLEL TO THE AXIS OF ROTATION OF SAID CYLINDRICAL TAPEGUIDE, SAID TRANSDUCER COMPRISING A MAGNET SYSTEM HAVING A PLURALITY OF POLE MEMBERS OF OPPOSITE POLARITY DEFINING THEREBETWEEN A PLURALITY OF HELICAL MAGNETIC GAPS, SAID PLURALITY OF POLE MEMBERS AND SAID PLURALITY OF HELICAL MAGNETIC GAPS BEING SITUATED IN A CYLINDRICAL SURFACE COAXIAL WITH THE AXIS OF ROTATION OF SAID TRANSDUCER AND TANGENTIALLY ENGAGING SAID CYLINDRICAL TAPEGUIDE, EACH OF SAID PLURALITY OF HELICAL GAPS HAVING AN ANNULAR EXTENT OF 360 DEGREES DIVIDED BY THE NUMBER OF SAID GAPS, SAID MAGNET SYSTEM INCLUDING ONE SINGLE MAGNET COIL AND MAGNETIC MEANS FOR LINKING WITH SAID COIL THE MAGNETIC FLUX ACROSS EACH OF SAID PLURALITY OF HELICAL MAGNETIC GAPS; AND A MAGNETIC TAPE RUNNING FROM SAID SUPPLY-REEL THROUGH A NIP FORMED BETWEEN SAID CYLINDRICAL TAPE-GUIDE AND SAID PLURALITY OF POLE MEMBERS TO SAID TAKE-UP REEL WHEREBY A POINT-FORM ENGAGEMENT IS EFFECTED BETWEEN SAID PLURALITY OF HELICAL MAGNETIC GAPS AND SAID TAPE.