Magnetic heads with means for preventing side erosion

Claim 1

AN ANNULAR MAGNETIC HEAD FOR RECORDING, REPRODUCING AND/OR ERASING MAGNETIC RECORDINGS IN A NARROW TRACK OF A MAGNETIC CORD CARRIER, COMPRISING AT LEAST TWO CIRCUIT PARTS COMPOSED OF SINTERED OXIDIC FERROMAGNETIC MATERIAL, SAID PARTS BEING SEPARATED BY A USEFUL GAP FILLED WITH A FIRST NONMAGNETIC MATERIAL WHICH PROTECTS THE GAP AND BONDS THE TWO CIRCUIT PARTS TOGETHER, A PORTION OF SAID CIRCUIT PARTS AND SAID GAP FORMING A GUIDE SURFACE HAVING A PLURALITY OF SIDES, SAID SIDES OF SAID GUIDE SURFACE HAVING A PLURALITY OF SIDES, SAID CIRCUIT PARTS BEING COVERED WITH A LAYER OF A SECOND NONMAGNETIC MATERIAL WHICH IS BONDED TO SAID FERROMAGNETIC MATERIAL AT ALL OF SAID SIDES AND SAID ANOTHER PORTION AND WHICH EXTENDS OUTWARDLY FROM EACH OF SAID SIDES, SAID LAYER HAVING A MECHANICAL STRENGTH AND RESISTIVITY TO WEAR SUBSTANTIALLY EQUAL TO THAT OF THE SINTERED OXIDIC FERROMAGNETIC MATERIAL, THE PART OF SAID LAYER WHICH IS ADJACENT TO THE RECORD CARRRIER DURING OPERATION OF THE HEAD BEING SUBSTANTIALLY CO-PLANAR WITH THE GUIDE SURFACE OF THE HEAD.