SU1541668A1 - Method of measuring value of angle of mutual inclination of synchrosound and erasing heads in magnetic head unit - Google Patents

Abstract

The invention relates to instrument engineering, in particular, to a technique of magnetic information recording, and can be used to control a block of magnetic heads of a video recorder. The purpose of the invention is to improve the accuracy of measuring the magnitude of the mutual inclination angle of the synchro-sound and erase magnetic heads. First, the interference pattern from the surface of the synchro head is formed in the form of stripes, then the interference pattern in the form of a line in the shape of a part of the ellipse from the erasing head. The coordinates of the vertex of the interference line and two points obtained from the intersection of this line with a straight line parallel to the tangent to the vertex of the interference line are measured. Then, the angle α of relative inclination of the surfaces of the heads is determined from the relation α = B ² / 8RH, where H is the distance between the top of the interference line and the straight line parallel to the tangent to the top of the interference line

B is the distance between the points of intersection of the direct interference line

R is the radius of curvature of the cylindrical surface of the erasing head.

Description

The invention relates to instrumentation, in particular to a technique of magnetic information recording, and can be used in stands for sorting blocks of magnetic heads of the video and video neophone.

The aim of the invention is to improve the accuracy of measuring the magnitude of the mutual inclination of the synchro-sound and erasing heads in the block of magnetic heads.

FIG. Figure 1 shows a cylindrical magnetic head, a section by an inclined plane; 2 is an optical diagram of the device for implementing the method; FIG. 3 and 4 are an image of interference patterns from surfaces of a synchro sound and erasing heads, respectively, in the plane of measurement.

The essence of the invention is as follows.

A block of magnetic heads, including a synchronous and erasing head, is set relative to the luminous flux so that an interference pattern is observed in the measurement plane

4b

about smiling

00

 from the synchronous head in the form of parallel strips (thick lines in FIG. 3)), which means that zero is set.

Then, in place of the synchro-sonic head, an erasing head is installed, the cylindrical surface of which is generally not parallel to the surface of the synchro-sound head. In the plane of measurements, an interference pattern of the fading hflova is observed, which has the form of several lines in the shape of a part of an ellipse, since when the cross section of the cylindrical surface of the bias is inclined, an ellipse is formed in the cross section (Fig. 1). IG) of the lines obtained choose the most contrast (thick line in FIG. M,

AB / 2P, N

j B2 tr ™.

whence with AB (O

The method is implemented by a device comprising a mechanism 1 for fastening a block of 2 magnetic heads (Fig. 2), an interference system 3, with the aid of

10 of which the image of the cylindrical surfaces of the heads is transferred to the target of the photodetector A, video camera 5, a block of 6 measurements, in which the measuring lines are formed,

15, the power supply source 7, the illuminator 8, which illuminates the surface of the heads through the intertitle system, the monitor 9 on the screen of which are displayed

the coordinates of its vertex are determined. The coordinates of two points of the interference line located at the intersection of this line with a straight line running parallel to the tangent line, checked to the top of the interference line 25 at the H.

The distance B between these points is also measured. Then, the angle c (in radians) of the mutual inclination of the cylindrical surfaces of the synchro-sound convoy and erasing heads is calculated using the formula

surfaces of synchro and erasing magnetic heads.

The device works as follows.

The required position of the block of 2 heads (Fig. 2) with working clearances 12 (Fig. 3 and t) is achieved by fixing in the fixing mechanism 1 and using the interference optical system 3 is projected onto the target of the photodetector k, the signal from the photodetector is processed by the block control of the video camera 5, then the video signal is transmitted to the electronic measurement unit 6, with which it will form measuring pulses and enter into the de-signal the image of the surface of the block of magnetic heads in the form of measuring lines 10 and 11 (FIG. 3 and 0). Transmission to the monitor screen 9. Illumination of the measured head is carried out through the path of the interference system using a light guide and an illuminator. Michelson's interferometer circuit is used as an interference system.The power supply of all elements of the electronic part of the device is supplied by a power source 7.

/ - B2 01 8RH

where H is the distance between the vertices.

interference lines and 35 | a straight line parallel to the tip of the inter- ference1 of the ZION LINE;

B - the distance between the points of intersection of the direct interfere - 40

CENTRAL LINE

R is the radius of curvature of the cylindrical surface of the erasing head.

Figure 1 shows the point M on 45

surface erasing head with the current coordinates X and (R-Y). Since it lies on a circle of radius R OM, which is a cross-section of the cylindrical surface of the plane, the perpen-50 dical generator, its coordinates satisfy the equation X2 + (R - Y) 2 R2,

whence X V2RY (the 55 Y term of the second order is neglected), with

Y - 6y

X 2

Y оЫ1

receive:

 / 2Р, Н

j B2 tr ™.

whence with ab in (o

The method is implemented by a device comprising a mechanism 1 for fastening the block 2 of magnetic heads (Fig. 2), an interference system 3, using

where the image of the cylindrical surfaces of the heads is transferred to the target of the photodetector A, video camera 5, measurement unit 6, in which the measuring lines are formed, power supply 7, the illuminator 8, which illuminates the surface of the heads through the interrupt system, the monitor 9 on the screen of which

cylindrical lines and image

surfaces synchro and erasing magnetic heads.

The device works as follows.

The required position of the magnetic heads unit 2 (Fig. 2) with the working gaps 12 (Figs. 3 and t) is achieved by fixing in the mounting mechanism 1 and is projected onto the target of the photodetector k using the interference optical system 3, the signal from the photoreceiver is processed by the control unit of the video camera 5, then the video signal is transmitted to an electronic unit of 6 measurements, with the help of which measuring pulses are formed and the image of the surface of a block of magnetic heads is introduced into the video signal in the form of measuring lines 10 and 11 (Fig. 3 and Full TV This signal is transmitted to the monitor screen 9. The illumination of the measuring head is carried out through the path of the interference system-L by means of a fiber and an 8L illuminator. The Michelson interferometer is used as an interference system.The power supply of all elements of the electronic part of the device is supplied by the power source 7.

Claims (1)

Invention Formula  measurement of the angle of mutual inclination of the synchro-sound and erasing heads in the block of magnetic heads, in which an image of the cylindrical surfaces of the synchro-sound is formed in the plane of measurement and erasing heads, choose the reference points of the measurements, the coordinates of which are determined, and then, based on the results of the obtained measurements, the angle of mutual inclination of the cylindrical surfaces of the magnetic heads is calculated, characterized in that magnetic heads, the luminous flux reflected from the synchronous head, form the interference pattern in the form of parallel stripes, then in place of the synchro sound head is set with an abrasive head, from the cylindrical surface of which an interference pattern is formed in the form of a line having the shape of a part of an ellipse, after which the angle c is determined (the relative inclination of the synchro and erasing heads from the ratio .91  8RH where B is the distance between the points of intersection of the direct interference line, R is the radius of curvature of the cylindrical surface erasing HEADS | H is the distance between the top of the interference line and the straight line crossing this line at two points and parallel to the tangent to the top of the interference line. FIG. g, .12 Fig.Z . / °, K C) iga