GB2157051A

GB2157051A - Structure for mounting shield cover of a magnetic head

Info

Publication number: GB2157051A
Application number: GB08430057A
Authority: GB
Inventors: Kiyoshi Matsui
Original assignee: Alps Electric Co Ltd
Current assignee: Alps Alpine Co Ltd
Priority date: 1984-04-02
Filing date: 1984-11-28
Publication date: 1985-10-16
Also published as: GB8430057D0; GB2157051B; JPS60159514U; KR900006057Y1; KR850009653U

Abstract

A structure for mounting a shield cover (6) of a magnetic head comprises head assembly (A), shield cover (6), printed circuit board (7) supported on the shield cover and having a conductive pattern connected to the terminals of a magnetic head, and a connector case (8) secured to the p.c.b. The shield cover (6) is sandwiched between the connector case (8) and mounting plate (5). Moreover, the shield cover (6) has an engaging part (6b1) which engages the mounting plate (5). The arrangement eliminates screw (17) (Figure 2) for mounting the shield cover. The above structure may be provided for heads 1 or 2 individually. <IMAGE>

Description

SPECIFICATION Structure for mounting shield cover of magnetic head Field of the invention The present invention relates to a structure of mounting shield cover of magnetic head and particularly to a structure for mounting shield cover of a large size magnetic head such as a voice magnetic head for VTR.

Background of the invention A magnetic head assembling body consisting of an erasing head called the voice magnetic head for VTR and a recording/playback head is provided with a shield cover in the side opposing to the magnetic tape contact surface in view of receiving no influence of external magnetic field.

In case of a magnetic head having simplified structure, a shield cover, for example, consisting of permalloy material is fixed by bonding or pressurized engagement only to the rear surface of recording/playback head. But in this case, the head is likely to be influenced by external field and recently a shield cover having complicated shape is used.

Fig. 1 and Fig. 2 shows an existing structure for mounting shield cover of voice magnetic head for VTR. Fig. 1 is a perspective view indicating the assembled condition, while Fig. 2 is a perspective view of disassembled condition.

In the figures, 1,2 are magnetic heads. For istance, 1 is a recording/playback head and 2 is a erasing head. Both magnetic heads 1, 2 and the combined shield cases 1a, 2a form a magnetic head assembling body A.

4 is terminal of both magnetic heads 1, 2. 5 is a mounting plate to which such magnetic head assembling plate A is mounted. 6 is a shield cover which is made of permalloy, for example, and covers the magnetic head assembling body A. This shield cover is composed of the upper plate 6a which covers the upper surfaces lea,, 2a, of the shield cases 1a, 2a of said recording/playback head 1 and erasing head 2, the rear plate 6b which covers the rear surfaces la2, 2a2 and the side plate 6c which covers the side surfaces la3, 2a3. The width B of the rear surface of upper plate 6a of shield cover 6 is a little larger than the width C of the magnetic head assembling body A and the rear plate 6b of the shield cover 6 provided with holes (not shown) to which the terminals 4 of magnetic heads 1, 2 can be inserted.

7 7 Is a printed circuit board having conductor pattern (not shown) at the rear surface. 14 is a hole to which the terminal 4 of said magnetic heads 1, 2 is inserted. 8 is a connected case made of an insulator -ixed to the one end of the surface of said printed circuit board 7. 9 is a connector implanted to said case 8. 10 is a mounting hole provided to the upper plate 6a of the shield cover 6. 11 is a tap hole provided to the upper surface la, of the shield case 1a of recording/playback head 1. 12 is a mounting hole provided to the mounting plate 5.

13 is a screw for tightening the shield case 1a of recording/playback head 1 to the mounting plate 5.

17 is a screw for fixing the shield cover 6. 15 and 16 are cores of magnetic heads 1,2.

Next, the procedures for mounting the shield cover 6 to the magnetic head assembling body A are described below.

First, a screw 13 is attached through the mounting hole 12 of mounting plate 5 and is tightened into the screw hole (not shown) of the shield case 1a of recording/playback head 1 in order to tighten the magnetic head assembling body A to the mounting plate 5.

The magnetic head assemling body A is covered with the shield cover 6 from the direction of arrow mark D shown in Fig. 2 and thereby the terminal 4 is protruded from the rear plate 6b of shield cover 6. Thereafter, the screw 17 is attached through the mounting hole 10 of the upper plate 6a of the shield cover 6 and is then screwed into the tap hole 11 of shield case 1a. Thereby, the shield cover 6 is fixed to the magnetic head assembling body A.

The surface of printed circuit board 7 fixing the connector case 8 is placed over the rear plate 6b of shield cover 6, thereby the terminal 4 is protruded from the rear surface through the engagement hole 14 of the printed circuit board 7 and the terminal 4 is soldered to the conductor pattern (not shown) at the rear surface of printed circuit board 7. Thereby the printed circuit board 7 is fixed to the shield cover 6.

However, said prior art has following disadvantages.

(1) The shield cover 6 must be provided with a mounting hole 10, while the shield case 1a with a tap hole 11. Moreover, after screwing the shiled cover 6 to the shield case 1a with a screw 17, the lock paint must be applied for preventing loosening of screw 17.

(2) A press mold is complicated in structure because the mounting hole 10 must be provided to the shield cover 6.

(3) Since the shield case la is made of a hard material such as permalloy, the tap may be liable to be broken while forming the tap hole 11.

The working efficiency is deteriorated due to correlation of above factors (1), (2) and (3).

(4) A mounting screw 17 is required, causing increase of a number of parts.

Summary of the invention It is therefore an object of the present invention to provide a structure for mounting a shield cover of magnetic head which assures excellent working efficiency and requires less number of parts. In order to attain such object, the present invention offers a structure for mounting shield cover of magnetic head comprising a magnetic head, a mounting plate to be fixed to said magnetic head, a shild cover which covers magnetic head, a printed circuit board which is loaded to said shield cover and has a conductor pattern connected to terminals of said mangetic head and a connecor case fixed to said printed circuit board, and holding the shild cover with said connector case and said mounting plate.

Brief description of the drawings Figure 1 and Figure 2 indicate an existing structure for mounting shield cover of voice magnetic head for VTR. Fig. 1 is a perspective view indicating the assembled condition. Fig.2 is a perspective view of dis-assembl d condition. Fig.3 and Fig.4 indicate an embodiment of the present invention.

Fig.3 is a perspective view of assembled condition.

Fig.4 is a perspective view of dis-assembled condition.

Detailed description of the invention The present invention is then described in detail with reference to a preferred embodiment of the invention by referring to attached drawings. Fig. 3 and Fig. 4 show an embodiment of the present invention. Fig. 3 is a perspective view of the assembled condition. Fig. 4 is a perspective view of disassembled condition.

The same parts as those in Fig. 1 and Fig. 2 are given the same symbols and these are not described in detail.

Difference between the present invention and prior art is described below. Namely, an engaging part which engages with the mounting plate 5, for example, a protrusion 6b, is provided to the end part formed by extending the lower edge of side plate 6c of shield cover 6 and on the other hand, the mounting plate 5 is provided with an engaging hole 18 for said protrusion 6b,. The connector case 8 is located in such a position where the lower surface 8a presses the upper plate 6a of the shild cover 6 when the terminals 4 of magnetic heads 1, 2 are engaged with the engaging hole 14 of printed circuit board 7 and the end points of terminals 4 are soldered to the conductor pattern at the rear surface of printed circuit board 7.

Next, the assembling procedures of structure for mounting shield cover of head assembling body are described below.

For example, first, the magnetic head assembling body A is fixed to the mounting plate 5 by the screw 13 as in the case of prior art. After the termi nals 4 are protruded from the rear plate 6b of the shield cover 6 by covering the magnetic head assembling body A with the shield cover 6 in the direction indicated by arrow mark D, the lower protrusion 6b, is inserted into the hole 18 of the mounting plate 5 until the bottom surface 6c, of side plate 6c is engaged with the surface of mount- ing plate 5.

Thereafter, the printed circuit board 7 is placed over the rear plate 6b of the shield cover 6 by engaging the terminals 4 of the magnetic heads 1 and 2 with the engaging holes 14 of printed circuit board 7 mounting previously the connector case 8 and the terminals 4 are soldered to the conductor pattern at the rear surface of the printed circuit board 7.

As described above, the shield cover 6 is mounted to the magnetic head assembling body A.

At the time of mounting, the connector case 8 is previously is placed so that the lower surface 8a presses the upper plate 6a of the shield cover.

Therefore, the shield cover 6 is held between the lower surface 8a of connector case 8 and the mounting plate 5 and fixed securely.

According to the present invention, following effects can be attained.

(1) A tap hole which has been required for the shield case 1a is no longer necessary.

(2) Structure of press mold can be very simplified because a mounting hole which has been required for the shield cover 6 is unnecessary.

(3) The screwing for shield cover 6 can be eliminated.

The working efficiency can be much improved as compared with the existing structure through combination of above factors (1), (2) and (3).

(4) The screw 17 for mounting the shield cover 6 is unnecessary and a number of parts can be reduced.

(5) Since the shield cover can be mounted by engaging the protrusion 6b, provided thereto with the engaging hole 18 provided to the mounting plate 5, the shield cover 6 can be positioned easily at the time of mounting. In above embodiment, the magnetic head assembling body A is formed by the recording/playback head 1 and the erasing head 2 and the shield cover 6 is provided in such a way as a covering such magnetic head assembling body A. But, the present invention is not limited only to such a structure and it is also possible to employ the modification wherein the aforementioned shield cover mouinting structure is provided for the recording/playback head 1 or erasing head 2 prepared individually.

As described in details above, the structure for mounting shield cover of magnetic head of the present invention assures the effect that excellent working efficiency can be attained, a less number of parts are required and positioning of shield cover can be done easily because the shield cover is held by the connector case fixed to the printed circuit board and the mounting plate, and the shield cover is engaged with the mounting plate.

Claims

1. A structure for mounting shield cover of magnetic head comprising a magnetic head, a mounting plate to be fixed to said magnetic head, a shild cover which covers magnetic head, a printed circuit board which is loaded to said shield cover and has a conductor pattern connected to terminals of said magnetic head and a connector case fixed to said printed circuit board, and holding the shild cover with said connector case and said mounting plate.

2. A structure for mounting shield cover of magnetic head according to claim (1), wherein an engaging part is provided to said shield cover and thereby the shield cover and said mounting plate are engaged through such engaging part.

3. A structure for providing a shield cover for a magnetic head assembly substantially as hereinbefore described, with reference to Figures 3 and 4 of the accompanying drawings.