SU1107166A1 - Device for positioning magnetic heads - Google Patents

Abstract

A POSITIONING DEVICE FOR MAGNETIC HEADS containing a carriage of magnetic heads, a primary coil of the sensor fixed fixedly relative to the carriage, a secondary coil of the sensor attached to the carriage, a generator associated with a frequency divider, characterized in that, in order to improve the reliability and simplify the device, A magnetostrictive rod, an amplifier-shaper, a trigger, an AND circuit are introduced, and the output of the frequency divider is connected to the primary coil of the sensor installed at the end of the magnetostrictive a rod fixed relative to the magnetic heads carriage, the axis of the secondary sensor coil is parallel to the axis of the magnetostrictive rod, and the coil is connected via an amplifier-shaper to the first trigger input, the output of which is connected to the first input of the And circuit, the second input of which is connected to the generator, and the divider output is connected with the second trigger input. (L L / b and O5

Description

This invention relates to the field of magnetic recording and can be used in magnetic disk drives.

A positioning device is known which contains a magnetic head carriage, first and second scales, first and second photosensors, a light source, an address determination circuit, the first scale attached to the magnetic head carriage, and the second scale parallel to the first one fixed to the magnetic head carriage. In the device, the light source, the first and second photosensors are located on opposite sides of the scales and are connected to an address determination circuit.

When the carriage of magnetic heads moves in certain positions, the scratches on the first and second scales coincide, and the light from the source hits the first and second photosensors, producing signals by which the address determination circuit detects the current position of the magnetic heads 1.

The disadvantage of this device is its sensitivity to contamination (dust, etc.), which deteriorates the transparency of the scales, which reduces the reliability of operation.

A positioning device is known comprising a generator, a frequency divider, an integrator, a transformer, a primary and secondary sensor coils, a magnetic head carriage, a demodulator, the generator through a frequency divider, an integrator, and a transformer connected to the primary coil of the sensor located on the magnetic head carriage, and the secondary the sensor coil, located parallel to the primary one, is mounted stationary relative to the carriage of magnetic heads, consists of two groups of alternating conductors and is connected to the demod l toor 2.

The disadvantages of the known device are the relative complexity of the design of the primary and secondary coils of the sensor, since their dimensions must be maintained with great accuracy, low reliability, which is due to the short-term loss of the signal from the sensor or the effect of random interference may disrupt the normal operation of the device and for to restore the possibility of correct positioning of the positioner, it must be returned to the initial position (to the track "00 data carrier).

The purpose of the invention is to increase the reliability and simplify the positioning device.

The goal is achieved in that the device containing the magnetic heads carriage, the primary coil of the sensor fixed fixedly with respect to the carriage, the secondary coil of the sensor fixed on the carriage, the generator associated with the frequency divider is inserted magnetostrictive rod, amplifierformer, trigger, circuit I, moreover, the output of the frequency divider is connected to the primary coil of the sensor mounted on

the end of the magnetostriction rod fixed relative to the carriage of the magnetic heads, the axis of the secondary sensor coil is parallel to the axis of the magnetostriction rod, and the coil is connected through

the amplifier-driver to the first input of the trigger, the output of which is connected to the first input of the circuit I, the second input of which is connected to the generator, and the output of the divider is connected to the second input of the trigger.

FIG. 1 is functional

device layout; in fig. 2 - time diagrams for her work.

The device consists of a carriage of magnetic heads 1, a primary coil 2 of the sensor, a secondary coil 3 of the sensor, a generator 4, a frequency divider 5, a magnetostrictive rod 6, an amplifier-former 7, a trigger 8, a circuit 9, the generator 4, a divider 5, the primary coil 2 sensors connected in series. Primary coil 2 fixed at end

magnetostrictive rod 6 fixed relative to the carriage of magnetic heads, the axis of the secondary coil 3 of the sensor is parallel to the axis of the magnetostrictive rod 6 and fixed to the carriage of magnetic heads 1. The secondary coil 3 of the sensor is connected through the amplifier 7 to the first input of the trigger 8, the output of which is connected to the first input circuit And 9, the second input of which is connected to the generator 4, and the output of the divider 5 is connected to the second input of the trigger 8.

The device works as follows.

The generator 4 generates pulses with a period of €. The period of these pulses is divided by divisor 5 to the value T, and

 V

where t is the length of the magnetostrictive rod;

V is the speed of propagation of sound vibrations in a magnetostrictive rod.

These pulses are applied to the primary coil 2 of the sensor and to the input of the trigger 8, setting it to a single state. The primary coil 2 of the sensor, due to the magnetostrictive effect, excites 0 in the magnetostrictive rod 6 sound vibrations that propagate along its axis with velocity V.

Having reached the secondary coil 3 of the sensor, the sound vibrations due to the reverse magnetostrictive effect excite an electric current in it, which is generated by the driver amplifier 7 and is applied to the trigger 8, setting it to the zero state. At the output of the trigger 8, a signal of duration t is formed, with t.- 4, where E is the distance between the primary 2 and secondary 3 coils of the sensor. This signal gives permission to the circuit AND 9 and for the time i {from the output of the generator 4 to the output of the circuit AND 9 the passage P.impul ° t i- - () where f is the T-period of the pulses from the generator. The number of pulses n at the output of the device determines the actual position of the carriage of the magnetic heads at a given time. If it is necessary to obtain this value numerically, it is sufficient to transfer the number of pulses n to the scaling circuit. Thus, the proposed device provides continuous determination of the position of the magnetic heads, independent of some initial position, and confirms this information after a period T. Therefore, the accidental loss of pulses does not necessitate a return to the initial position, which increases the reliability of the operation of the positioning device. In addition, the primary and secondary sensors of the sensor are intended only for magnetic coupling with the magnetostrictive rod, and their design and manufacturing accuracy have little effect on the positioning accuracy.

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FIG. 2

Claims (1)

A MAGNETIC HEAD POSITIONING DEVICE comprising a magnetic head carriage, a primary sensor coil fixed fixed to the carriage, a secondary sensor coil mounted on the carriage, a generator coupled to a frequency divider, characterized in that, in order to increase reliability and simplify the device, it introduced a magnetostrictive rod, an amplifier-driver, a trigger, circuit I, and the output of the frequency divider is connected to the primary sensor coil mounted on the end of the magnetostrictive ster nya, fixed relative to the carriage of the magnetic head, the axis of the secondary coil of the sensor is parallel to the axis of the magnetostrictive rod and the coil is connected through a driver amplifier to the first input flip-flop, whose output is connected to a first input of AND gate, the second input of which is connected to the generator. and the output of the divider is connected to the second input of the trigger. FIG. 7