NEW RECORDING MEDIUM 



537 



parison with the remainder of the record-mecHum which was subjected 

 to the normal aUernatiug-current erase. 'J'liis effect becomes neghgible 

 if the separation between the record medium and the erase structure is 

 increased b}' | inch before the current is interrupted. This is accomi)Hshed 

 by u;?ing a solenoid -actuated moiuiting for the erase structure so ar- 

 ranged that the structure normally is retracted from the erasing position 

 and holds open a switch in the circuit to its coil. When erasure is desired, 

 the solenoid is actuated. This moves the erase structure into operating 

 position and releases the switch to energize the coil. When the erase 

 cycle is completed the solenoid is de-energized, and the erase structure 

 retracts, opening the switch at the end of its travel. Fig. 3 is a sketch 



SCHEMATIC 



PHYSICAL ARRANGEMENT 



Fig. 3 — Method of erasing magnetic recorder. 



