KR830000702B1 - Broadband signal magnetic recording and playback device - Google Patents

Abstract

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Description

Broadband signal magnetic recording and playback device

1 is a partial cross sectional and side view of a head support comprising a head drum unit of a video recorder, ie a head disc having two magnetic heads.

2 is a plan view of the head drum of FIG.

3 is an enlarged view showing the head disk mounting of FIG. 1 in detail, in which the central diaphragm is enlarged for clarity.

4 is a plan view of a central diaphragm having a circular central hole.

5 is a cross-sectional view of the central diaphragm of FIG. 4 by arrow V-V.

6 is a trust member for mounting the central diaphragm of FIGS. 4 and 5;

7 is a cross-sectional view of the trust member of FIG. 6 by arrow VIII-VIII.

8 shows another example of a central diaphragm having a triangular central hole.

9 shows another example of a central diaphragm having a non-circular center hole equipped with three contacts.

The present invention relates to an apparatus for magnetically recording and reproducing a wide area signal on a magnetic tape in a state of signal tracks obliquely adjacent to each other, in particular rotatable about a rotating side and partially cylindrical with a free end. One drive spindle, at least one magnetic head rotatable within the circular hardness around the rotational side of the drive spindles for recording and reproducing oblique signal tracks on a magnetic tape, is detachably fixed to a cylindrical portion near the free end of the drive spindles. A head support for a magnetic head having a center hole formed thereon for mounting on a drive spindle, and a device for removably mounting the head support on the drive spindle, and also centering the head support relative to the rotational side of the drive spindle. Centering device and magnetic head support and drive It relates to a device consisting of a fixing device for tightly connecting the spindles to each other.

The device of the type described above is used in a so-called spiral scanning video recorder for magnetically recording and reproducing video signals. These video recorders are mass produced for the consumer market. Known consumer video recorders for magnetically recording and reproducing signals are of the latest state of the art. This is because the signal is subjected to very severe conditions that must be accurately recorded and reproduced on the magnetic tape by a rapidly rotating magnetic head. Magnetic tapes are always accommodated in certain standard cassettes. One of the important conditions is that when copying a cassette already recorded with one video recorder to another similar type of video recorder, the copy quality must be copyable without noticeable degradation compared to the original recorded copy quality. . In fact, these interchange conditions of certain standard cassettes and video recorders are generally referred to as compatible conditions.

Considering the most economical use of magnetic tape used in cassettes and the play time that can be taken with a particular cassette, attempts have been made to minimize the density of signals recorded on magnetic tapes with video recorders. In a recent video recorder for general consumers, oblique tracks are recorded by two magnetic heads on a magnetic tape. These tracks are usually about 40 microns wide. The distance between successive tracks is about 30 microns, so the tracks slightly overlap each other. The length of the oblique track is about 100mm, which is quite large compared to the width of the track. The above mentioned dimensions for track width and track distance must be kept within some limits for the total length of the inclined track in light of compatibility conditions.

Limiting the track on the magnetic tape to a small tolerance reduces the tolerance limit for the position of the magnetic head, which means that the position of the magnetic head relative to the device of the video recorder that guides the tape along the head support requires a high degree of accuracy. do.

It is also important that for video recorders with a large number of magnetic heads being used, the synchronization of the signals reproduced by the magnetic heads must be very accurate. The synchronization error can come out as a visible timing error on the playback television screen causing an unstable condition at the top of the screen.

미크론 이하이어야만 한다. 또 다른 조건은 자기 헤드들이 정확한 방법으로 헤드 지지체의 주변에서 균일하게 격리되어야만 된다는 것이다. 예를들면, 두 개의 자기 헤드가 사용될때 두개의 헤드들간의 원호의 기장은 서로간에 3미크른 이상 차이가 나지 말아야 한다.During manufacture the magnetic head is for example located on a head support with special optical precision, ie a head support mounted on the spindle. The above-described tolerance of the magnetic heads for the rape guide members of the video recorder should be adjusted to about 5 microns in size so that the difference in height between the magnetic heads does not exceed 5 microns. In addition, when the diameter of the head support is 65 mm in the form of a rotary head disc, the funnel of the magnetic heads is

Should be less than micron. Another condition is that the magnetic heads must be uniformly isolated around the head support in a precise manner. For example, when two magnetic heads are used, the length of the arc between the two heads should not differ by more than 3 microns from each other.

미크론 범위 이내의 헤드 지지체의 정밀한 중심설정은 대단히 중요하다. 수리기술자에 의해 신속히 위치 정렬 장치없이 중심설정이 시행될 수 있는 것이 매우바람직하다. 공지된 장치에서 헤드 지지체는 특정하게 꼭맞는 헤드지지체의 중심구멍에 맞물리는 전술한 플랜지의 환상 돌출부상에 헤드 지지체를 장착시킴으로서 구동스핀들상에 중심설정된다. 상이한 실시예들에서는 스펀들과 중심구멍간에 배치된 중심부재를 사용한다. 스핀들돌과 구멍이 대량생산될 수 있는 경우의 공차로 보아, 그러한 구성으로서 상술한 아주 적은 허용 편심공차를 일치시키는 것은 불가능하지는 않지만 지극히 어려운 것이다. 그러므로 그러한 중심설정 방법들은 최신 비데오 레코더에 대해 만족스립지 못하다.Devices of the type mentioned in the introduction are for example introduced in US Pat. No. 3,422,230. In this arrangement the flanges are fixed to the drive spindles on which the head support can be mounted by screws. Flanks are precisely machined on the side facing the head support, and the head support already has magnetic heads so that at least the distance between the magnetic heads can be accurately adjusted in advance. This is necessary because the compatibility of the video recorder must not be lost when replacing or repairing the head support. Therefore, in order to fix and center the head support, such measures must be taken to ensure compatibility after removing the head support and replacing it with a new head support, for example for repair purposes. Given the small tolerances that can be tolerated with respect to the eccentricity of the magnetic heads with respect to the drive spindles,

Precise centering of the head support within the micron range is of great importance. It is highly desirable that the center setting can be implemented quickly by the repair technician without the alignment device. In known arrangements the head support is centered on the drive spindle by mounting the head support on the annular projection of the aforementioned flange which engages in the center hole of the specifically fitted head support. Different embodiments use a core material disposed between the spuns and the center hole. In view of the tolerances where spindle stones and holes can be mass-produced, it is not impossible, but extremely difficult, to match the very small allowable eccentricity tolerances described above with such a configuration. Therefore, such centering methods are not satisfactory for the latest video recorders.

It is an object of the present invention to provide a device of the type mentioned in the foreword which allows for a highly precise mounting of the head support on the drive spindle without the need for a special special precision measuring device. A feature of the present invention is that the centering device is made of a thin elastic plate material having a center hole for firmly fitting the glass ends of the drive spindles, and the center hole is formed when the free ends of the drive spindles are aligned with the portions of the adjacent central diaphragm. As a result of the force generated between the central diaphragm and the drive spindle, it has a central diaphragm manufactured in such a shape and dimensions that are elastically bent in the axial direction, and furthermore, to a limited extent the parts of the central diaphragm located between the connecting device and the central hole. It is slightly separated from the central hole of the central diaphragm to bend elastically, but has a connecting device for connecting the central diaphragm to the head support.

The use of a central diaphragm makes it possible to fix the head support in an unwavering manner during operation. Hardly polished drive spins are used with a nominal diameter of 6 mm and when manufactured with a diameter tolerance of 4 microns, a small size between 11 and 21 microns will be sufficient for the transverse dimension of the central hole in the central diaphragm. Lateral forces that will be affected during mounting can be easily obtained without the drive spindles being unacceptable and without the use of auxiliary devices.

In order to fix the central diaphragm to the head support, the head support has an annular contact surface concentric with the rotational axis of the drive spindles and the central diaphragm, and the connecting force for connecting the central diaphragm to the head support is far from the contact surface. A thrust member disposed on the axial surface of the central diaphragm and having an annular thrust surface concentric with the rotational side of the drive spindles, and further comprising a connecting device compressing the thrust member against the core material, thereby providing a It is advantageous to use the embodiment, which is characterized by including a threading device for clamping the central diaphragm.

In order to reduce the axial force that will be influenced on the drive spindle along the head support during assembly disassembly, one embodiment of the present invention is that the central hole in the central diaphragm is non-circular, and the central diaphragm is driven at at least three positions. It is characterized by contact with the spindle. The central hole is for example actually polygonal and preferably triangular.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Since the head drum unit of FIG. 1 is only a schematic diagram and is not directly related to the present invention, it is generally located and all other parts are omitted from the description. For a more comprehensive description of the head drum unit in a video recorder and the tape guide device for guiding magnetic tape along the head drum unit, a comprehensive reference to the present invention is given, for example, in SMPTE magazine, November 1978. Publication, pp. 87,767-771, "Machine Design and Considerations for Conical Scanning Video Tape Recorders," and US Pat. No. 3,422,230, supra.

The apparatus of FIG. 1 for magnetically recording and reading a wideband signal on a magnetic tape in break signal tracks extending obliquely adjacent to each other is a cylindrical drive spin rotatable about a rotation axis 1 and having a free end 3. It includes (2). The two magnetic heads 4 and 5 are rotatable about the axis of rotation 1 for recording and reproducing signals on the magnetic tape. In the form of a head dust 6 a head support is mounted on the drive spindles 2 near the autonomous end 3 and on the disk a magnetic head 4 and 5 are mounted. This is not shown in the figure because the manner in which the magnetic heads 4 and 5 are mounted on the head disc 6 is independent of the present invention. The head disc 6 has a center hole 7 for mounting the head disc on the drive spindles. In order to detachably mount the head disk on the drive spindle, the axis of rotation of the drive spindle 2 as well as a fixing device in the form of four bolts 9, in particular for fastening the head disc 6 and the drive spindles 2 to one another. An apparatus is provided comprising a central diaphragm 8 for centering a head support with respect to (1). The fixing device also includes a flange 10 fixed to the drive spindles 2 by a locking screw 11. Therefore, the head disk 6 can be rotated about the fixed drum 12 by the drive spindles 2, and this dream drives the motor (not shown) and the drive spindles 2 for driving the head disc 6. It involves a device for journaling. This motor and journal device are not shown in the drawings because they are independent of the present invention. The fixed drum 12 is fixed to the chassis portion 14 by four screws 13 through the flange 23.

The central diaphragm 8 includes a central diaphragm made of a thin elastic plate material, which has a central hole 15 for firmly fitting the free end 3 of the driving spindle 2. The central diaphragm is singly formed in the axial direction as a result of the force generated between the central diaphragm and the drive spindle, in which the parts of the central diaphragm near the center hole 15 at insertion of the free end of the drive spindles are particularly well illustrated in FIG. It has such a shape and dimensions to bend. In order to connect the central diaphragm 8 to the head disk 6, a connecting device is provided at regular intervals from the central hole 15 of the central diaphragm. Therefore, the portion of the central diaphragm 8 located between these connecting devices and the central hole is freely elastically deformed in a limited range.

The head disc 6 has an annular contact surface 16 concentric with the axis of rotation 1 of the drive spindle 2, with the center diaphragm 8 being located with respect to the surface thereof. The connecting device for connecting the central diaphragm 8 to the head disc 6 includes a thrust member 17 in the laterality of the central diaphragm distant from the contact surface 16. The trust member has an annular trust surface 18 concentric with the axis of rotation 1 of the drive spindles 2. Furthermore, the connecting device comprises three bolts 19 for compressing the trust member 17 against the central diaphragm 8 to clamp the central diaphragm 8 between the contact surface 16 and the trust surface 18. have.

In order to allow the bolt 19 to pass through, the central diaphragm 8 has three holes 20 that coincide with three holes 21 in the thrust member. The thrust member has a center hole 22 for passing the drive spindles 2 through.

The central diaphragm 8 of FIGS. 4 and 5 is made of chromium-nickel (I8Cr, 8Ni) spring steel worth about 0.1 mm in thickness. The outer diameter of the central diaphragm is about 20 mm and three holes 20 are located on a pitch circle of about 16 mm for the bolt 19 to pass through. The hole 20 coincides with the hole 21 of the trust 17. The central hole 15 of the central diaphragm 8 has a diameter of about 6 mm, to which the inner diameter of the annular trust surface 18 of the thrust member 17 is about 12 mm. As a result, the clearance between the thrust surface 18 of the thrust member 17 and the edge of the central hole 15 of the central diaphragm 8 is 3 mm.

An enlarged view is shown in FIG. 3 or a variant of the central diaphragm portion located between the central hole 15 and the trust surface 18. In fact, the axial deflection will not be more than about 0.2 mm. When the central diaphragm according to FIGS. 4 and 5, that is, the circular pit 15 and the diaphragm having a thickness of about 0.1 mm, about 1000 g of force is used to fit the head disc 6 on the drive spindles 2. Required. Smaller force is sufficient to remove the head disc 6. This is due to the deformation of the central diaphragm 8, which is bent during removal of the head disc 6 and requires less force than the force required by deflection when the head disc is mounted.

Center to FIG. 8 having a central diaphragm 25 or an approximately triangular center hole 24 used by FIG. 8 having a central hole 26 defined by a wall with three bulging lugs 27. When the diaphragm 23 is used, the force will be sufficient and the force may be several times smaller depending on the actual and dimensions of the central diaphragm, in particular the area of the center hole caution.

Claims (1)

And drive spindles (2) whose cylindrical part is at least in its column with a free end (3) rotatable about a rotation axis (1). At least one magnetic head (4, 5) rotatable in a circular path around the axis of rotation (1) of the drive spindles (2) for recording and reproducing oblique signal tracks on the magnetic tape; Magnetic heads 4 and 5 which are removably fixed to the cylindrical portion of the drive spindles 2 near the free end 3 and which have a central hole 7 for mounting the head support on the drive spindles 2. Head support 6, and Removably mounts the head support on the drive spindles and for firmly connecting the magnetic head support and the drive spins with a central device for determining the center of the head support 6 relative to the axis of rotation 1 of the drive spindles 2. In the wideband signal magnetic recording and reproducing apparatus provided in the fixing apparatus (9), The central seam is provided with a central diaphragm 8 made of a thin elastic sheet, which secures the free end 3 of the drive spindle 2 firmly and its shape and dimensions are adjacent to the central hole 15. It has a shape and dimensions that are elastically deformed in the axial direction by the force generated between the central diaphragm and the drive spine, and the central diaphragm 8 is fixed at regular intervals from the central hole 15 of the central diaphragm. Broadband, characterized in that the part of the central diaphragm (8) between the connecting device (17, 19) and the central hole (5) is elastically deformed within a limited range by installing a coagulation device (17, 19) connected to the Signal magnetic recording and reproducing apparatus.

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