Browse Prior Art Database

Magnetic Head Surface Formation

IP.com Disclosure Number: IPCOM000085164D
Original Publication Date: 1976-Mar-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 59K

Publishing Venue

IBM

Related People

Vair, GG: AUTHOR

Abstract

In U. S. Patent No. 3,921,340, a head is moved toward and rotated against an abrasive until a predetermined head resistance is detected. Here, in addition, the rate of resistance change is monitored to prevent overgrinding.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 60% of the total text.

Page 1 of 2

Magnetic Head Surface Formation

In U. S. Patent No. 3,921,340, a head is moved toward and rotated against an abrasive until a predetermined head resistance is detected. Here, in addition, the rate of resistance change is monitored to prevent overgrinding.

Referring to the figure, there is illustrated a logic configuration capable of performing a calculation for determining the unknown resistance X. Signals on the bus 35 from a resistance bridge are gated into AND circuits 201, 202 and 203, when a measure and store signal occurs on line 211, to circuits which calculate the current head resistance X. A quantity XLim, representing a predetermined limit resistance value, is stored in a register 210 and compared with the calculated quantity X in a comparator 207.

A signal occurs on line 219 when the X quantity equals XLim and a measure and store signal occurs. Line 219 remains activated until X is less than XLim. The calculated quantity X is stored in the X register 200, which is reset by every measure and store signal on line 211, and is also gated by a signal on a display line 214 through AND circuit 215 to a last X register 16 which holds the previous head resistance.

A start signal on line 227 from an external source sets the flip-flop 218 to the one condition, enabling AND circuit 228 to pass a series of clock pulses from a clock 235 which steps a ring counter 236 from position to position in sequence. As the ring counter 236 is stepped, AND circuits 229-234 are...