JPS61107521A - Measuring device of height of head for flexible magnetic disc device - Google Patents

Abstract

PURPOSE:To measure simply the height of a head face to a disc fixed face without diassembling the titled device by pressing a cantilever to a slide face between a magnetic head and a disc to detect the change in the height of the magnetic head sliding face to a turntable as a deflection change of the flat plate cantilever. CONSTITUTION:A seat 2 is pressed into contact onto the turntable 5 of the magnetic disc device via a disc retainer 7 by a plate spring 6 for disc loading. The magnetic head 8 is placed to a head carriage 9 and moved in the direction of arrow and positioned. An arm 10 supported by the head carriage 9 is energized by a spring to act like contacting closely the disc onto the head via a felt-made pad 11 provided at the tip. The deflection of the flat plate 1 is changed attended with the vertical movement of the magnetic head 8, a resistance wire strain gauge 4 is deformed and its resistance value is changed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a flexible magnetic disk device, and particularly to a device for measuring the height of a magnetic head surface relative to a disk fixing surface.

[Background of the invention]

In a magnetic disk device using a replaceable flexible magnetic disk as a record carrier, the positions of the disk and head must be maintained with high precision. In particular, the mounting height is one of the important performance factors of the device, as it relates to fluctuations in the amplitude of the reproduced signal, wear of the disk, misalignment of the head in the track direction, and the like. Conventionally, the height of the sliding surface of the magnetic head relative to the rotary table surface that fixes the disk is measured by measuring the height from a certain reference surface using a hide gauge or tool microscope. Microscopes are also stipulated in the Japanese Industrial Standards. (B-7153, 7517) It is a general purpose measuring instrument. However, in order to use these devices, a certain amount of space is required for measurement, and there are disadvantages such as a long measurement time, which takes several tens of seconds or more.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a device that can easily measure the height position of a head surface relative to a disk fixing surface without disassembling the device.

[Summary of the invention]

In the present invention, a cantilever beam whose fixed end is the part that contacts the rotary table on which the disk is mounted is purchased, and this cantilever beam is pressed against the sliding surface of the magnetic head against the disk, and the magnetic head against the rotary table is A change in the height of the head sliding surface is taken as a change in deflection of a flat plate cantilever beam, and a strain change is detected as a change in 12 resistances with an adhesive resistance wire strain meter installed on the beam.〇 [Embodiment of the invention] Below, An embodiment of the present invention will be explained with reference to the drawings.
The figure shows the structure of a cantilever beam, where 1 is a flat plate that constitutes the beam, 2 is a pedestal that is in contact with the rotary table surface of the magnetic disk device, and 3 is a pedestal 2 that adhesively holds the cantilever beam 1 and the pedestal 2.
, 3 have a shape that is compatible with the disk fixing method of the magnetic disk device. The flat plate 1 has a tongue shape as shown in the figure, and has a pressure contact portion 1- between the pedestal fixing portion 1-cL and the head surface.
An adhesive resistance wire 8 and a strain gauge 4 are provided on both sides between the two sides. FIG. 2 is a side sectional view showing the state in which the cantilever assembly shown in FIG. The disks are pressed together via the disk presser 7. A magnetic head 8 is mounted on a head carriage 9 and is moved and positioned in the direction of the arrow. 1
Reference numeral 0 denotes an arm pivotally supported by the helad carriage 9, which is biased by a spring (not shown) and functions to bring the disk into close contact with the head through a felt pad 11 provided at the tip. In FIG. 2, the arm 10 is shown in an open state in a lifted state. In this embodiment, the thickness of the pedestal 2 is made smaller than the actual disk pedestal 1 so that the flat plate 1 is in contact with the sliding surface of the head 8 even if the height of the head 8 is lower than a predetermined value. Alternatively, the flat plate 1 may be deformed in advance so as to come into pressure contact with the head 8. As the magnetic head 8 moves up and down, the deflection of the flat plate 1 changes, the resistance wire strain meter 4 deforms, and the resistance value changes. Figure 3 shows a circuit for detecting changes in the resistance value of the strain meter, including a strain meter 4 and a fixed resistor 30.
Voltage changes are extracted by a pre-requisite circuit constructed of . FIG. 4 shows an example in which the above-described cantilever assembly is housed in a 3-inch compact floppy disk, where 20 is a disk teeth, 22 is a head window shutter,
23 is a band-like member for opening and closing the shutter 22, and 24 is a spring that biases the shutter 22 in a closed state. The shutter 22 is rotatably attached to the case 20, and a band member 23 is locked at its tip, and a shutter biasing spring 24 is locked at the other end of the band member 23. Cantilever beam assembly 2
A bottle 25 is placed on the opposite side of the beam part of the flat plate 1 that constitutes the beam 4.
is fitted into an index hole 20α in the case 20.

Therefore, the beam is always above the magnetic head. When actually used, the head height may be calibrated for a known head. FIG. 5 is a graph calibrated without arm 10. If you want to measure with the arm 10 in an actual disk device, you can create a calibration curve in a similar state. In the above-described embodiment, the head height detection cantilever beam assembly can be easily housed in the disk case and is protected by the shutter so that the beam portion will not be damaged.

〔Effect of the invention〕

According to the present invention, the head height can be measured simply by attaching a disk case incorporating a head height detection cantilever to the disk device to be measured in the same way as a normal disk device. Not only can the measurement time be significantly shortened from several minutes to several seconds, but the head height in the final product can be measured and checked without disassembling the device. Furthermore, since the detection cantilever beam is housed in a disk case, the beam is not damaged and is reliable.

[Brief explanation of the drawing]

Figure 1 is an exploded perspective view of the head height detection cantilever, Figure 2 is a side sectional view showing how the cantilever is used, Figure 3 is a circuit diagram of the detection bridge, and Figure 4 is an exploded view of the disk case. The perspective view, FIG. 5, is a characteristic diagram for determining a calibration value between head height and output voltage. DESCRIPTION OF SYMBOLS 1...Flat cantilever beam, 2.6...Pedestal, 4...Adhesive resistance strain meter, 5...Rotary table 1 8...Magnetic head, 20...Disk case, 20α・...Index hole, 25...Pin, 60...Fixed resistance. 1st 2nd blunder / θ 3rd hard 5th exclamation Fig. 4

Claims (1)

[Claims] 1. A tongue-like flat plate having one end that is brought into close contact with a rotary table that rotationally drives a disk of a flexible magnetic disk device and a portion that comes into pressure contact with a disk contacting surface of a magnetic head, and abutment of the tongue-like flat plate with the rotary table. 1. A head height measuring device for a flexible magnetic disk drive, characterized in that an adhesive resistance strain gauge is provided on at least one surface between the magnetic head contact portion and the magnetic head contact portion.