JPH0319053Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic erase head, and more particularly to the structure of a magnetic erase head in a cassette tape system.

In general, the track of the magnetic erasing head in a cassette tape system is as shown schematically in FIG.
It has a width that can erase the lower half of the magnetic tape 3 running in the direction, that is, W/2 (where W: magnetic tape width). In this case, approximately half of the tape width of the magnetic tape runs in areas other than the track for erasing.

FIG. 2 shows an example of a conventional magnetic erase head of this type. In this figure, a tape sliding surface 2 of a magnetic erasing head 1 corresponding to a track T for erasing is shown.
The core 4 that makes up the gap G is exposed.
The other part of the tape sliding surface 2 is constituted by the case 5 of the erasing head 1.

However, if there is enough space to cover the core 4 of the track with the case 5 as in the configuration shown in FIG. However, if there is no space to use a case to support the core, such as a small window erasing head that performs the erasing operation while inserted into the small window of the cassette half of a cassette tape, it may be necessary to or assembly problems.

FIGS. 3 and 4 show a magnetic erase head that has been proposed as a conventional small window erase head. In these figures, C-shaped cores 13A and 13B are butted against an I-shaped core 11 provided with a coil 10 via a non-magnetic gear spacer 12, and a non-magnetic dummy block 14, which forms approximately half of the tape sliding surface, is attached. It is attached by adhesive to form a magnetic erase head.

However, in the configurations shown in FIGS. 3 and 4, the I-type core 11 and the C-type core 1 are used to form the gap G.
It is necessary to insert the gear spacer 12 when joining the cores 11, 13A, 13B, and the dummy block 14 is glued etc. to each core 11, 13A, 1.
It must be provided in the front notch part of 3B. For this reason, the number of parts is large and the number of assembly steps is large, which is inconvenient in terms of improving mass productivity and reducing costs.
Furthermore, since the periphery was not surrounded by a case, there was a risk that the dummy block would peel off and fall due to poor adhesion.

In view of the above points, the present invention has a durable structure that prevents the dummy block from falling off by forming the dummy block that forms the tape sliding surface integrally with the bobbin for winding the coil with wear-resistant resin. The present invention aims to provide a magnetic erasing head that is easy to assemble and can reduce costs.

Embodiments of the magnetic erasing head according to the present invention will be described below with reference to the drawings.

FIG. 5 shows a completed magnetic erase head 20 that can be used as a small window erase head. This magnetic erasing head 20 consists of a head main body 23 in which a gap G is formed between an I-shaped core 21 made of ferrite or the like and C-shaped cores 22A and 22B made of ferrite, and a case 24 made of plastic or non-magnetic metal. A tape guide 25 is attached to the side surface of the head body 23 as required.

As shown in FIGS. 6 and 7, the head body 23 includes an I-shaped core 21 and C-shaped cores 22A, 22.
B and the coil 2 provided around the I-type core 21
6 is wound on the bobbin 27. As shown in FIGS. 8 and 9, the bobbin 27 has a dummy block 30 and a plate-shaped protrusion 31 for forming a gap at the front, and a terminal section 32 at the rear, which is approximately the same as the core part. Molded in one piece from wear-resistant plastic. As the wear-resistant plastic, a thermosetting resin such as an epoxy resin mixed with an inorganic filler such as alumina powder or vitreous powder can be used. A terminal pin 33 is fixed to the terminal portion 32, and the winding end of the coil 26 is attached to the terminal pin 33 and soldered.

The I-shaped core 21 has a notch 40 corresponding to the dummy block 30 at the tip, and the length of the tip in the upward direction (the length of the tip facing the tape sliding surface) is equal to the track width. It's starting to match. Then, the tip of the I-shaped core 21 is inserted into the bobbin 27 so that it is sandwiched between the dummy block 30 and the plate-like protrusion 31. Here, the width of the plate-shaped protrusion 31 is slightly larger than the thickness of the I-shaped core 21, and both side surfaces of the plate-shaped protrusion 31 protrude slightly from both sides of the I-type core 21.

On the other hand, the C-shaped cores 22A and 22B also have a notch 41 at the tip corresponding to the dummy block 30, and the length of the tip surface in the vertical direction is such that it can come into contact with the plate-like protrusion 31. It is set to be longer than the I-shaped core 21 by the thickness of the plate-like protrusion 31 . These C-shaped cores 22A, 22B are butted against the side surface of the I-shaped core 21, but at this time, the C-shaped cores 22A, 22B are positioned according to the diagonal lines of the dummy block 30 and the terminal portion 32, as shown in FIG. This can be done easily by using the parts marked with . C-type core 2 on the side of I-type core 21
When 2A and 22B are butt-joined, since the width of the plate-shaped protrusion 31 is larger than the thickness of the I-shaped core 21, the tip of the I-shaped core 21 and each C-shaped core 2 are inevitably connected.
A gap is created between the tips of 2A and 22B. This gap will become a gap G when completed. In this way, the head main body 23 is completed, as shown in FIG. 6, before adhesive and filler are applied.

On the other hand, the case 24 has a rectangular parallelepiped outer shape as shown in FIGS. 10 and 11, and has a through hole 50 that fits into the head body 23.
The rear portion thereof is a large window portion 51 into which the terminal portion 32 can be inserted. And the sixth
The head main body 23 as shown in the figure is fitted into the case 24, and adhesive and filler are poured into them. As a result, the head main body 23 is fixed to the case 24 while protruding forward from the case 24, and the adhesive and filler flow into the gap between the I-shaped core 21 and the C-shaped cores 22A and 22B, forming a gap G. Ru. Thereafter, the front surface of the head body 23, which will be the tape sliding surface, is polished to a mirror-like finish, completing the magnetic erasing head 20 as shown in FIG.

According to the above embodiment, the following effects can be achieved.

(1) Since the dummy block 30 is integrally formed with the bobbin 27 from plastic having approximately the same wear resistance as the core portion, the number of parts can be reduced and the assembly work can be simplified.

Furthermore, even if the dummy block 30 is not surrounded by a case, the dummy block 30 is a resin molded product integrated with the bobbin 27, so there is no risk of the dummy block 30 falling off, and it is mechanically strong and reliable. It's also expensive.

(2) A plate-like protrusion 31 having a width slightly larger than the thickness of the I-shaped core 21 is formed integrally with the bobbin 27 from wear-resistant plastic to define the gap (thickness) of the gap G. Therefore, it is possible to eliminate the need for a gear spacer, which was necessary in the past, and it is possible to reduce the number of parts and improve assembly workability.

(3) The dummy block 30 and the terminal portion 32 provided integrally with the bobbin 27 are connected to the C-shaped cores 22A, 2
Since it acts as a positioning member when butting 2B against the I-shaped core 21, there is an advantage that assembly work can be facilitated in this respect as well.

(4) It is possible to reduce assembly man-hours, improve mass productivity, and reduce costs.

(5) By appropriately selecting the viscosity of the plastic forming the bobbin 27, it is possible to make the bobbin 27 smaller and, by extension, the head smaller.
It can also be applied to magnetic erase heads for microcassettes.

In addition, the terminal part may be separate from the bobbin,
As the material of each core, other than ferrite, a metal magnetic material, or a combination of ferrite and metal magnetic material, etc. can be adopted.

As described above, the present invention provides a magnetic erasing head that is mechanically strong, improves assembly workability, and reduces cost.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the tracks of a magnetic erasing head in a cassette tape system, Fig. 2 is a front view showing an example of a conventional magnetic erasing head, and Fig. 3 is a diagram of a conventional magnetic erasing head proposed as a small window erasing head. An exploded perspective view of the magnetic erasing head, FIG. 4 is the same perspective view,
FIG. 5 is a perspective view showing an embodiment of the magnetic erasing head according to the present invention in a completed state, FIG. 6 is a perspective view showing the head body in the embodiment, FIG. 7 is an exploded perspective view of the same, and FIG. 8 Figure 9 is an exploded perspective view showing the structure of the bobbin and I-type core, Figure 9 is a side view showing the bobbin, Figure 10 is a perspective view of the case viewed from the front, and Figure 11 is a perspective view of the case viewed from the rear. be. 1, 20... Magnetic erase head, 2... Tape sliding surface, 3... Magnetic tape, 5, 24... Case,
10, 26... Coil, 11, 21... I-type core, 13A, 13B, 22A, 22B... C-type core, 14, 30... Dummy block, 23... Head body, 27... Bobbin, 31... ... Plate-like protrusion, 32 ... Terminal part, 33 ... Terminal pin, 40,
41...Notch, 50...Through hole, G...Gap.

Claims (1)

[Claims for Utility Model Registration] (1) A C-shaped core is butt-jointed on both sides of an I-shaped core provided with a bobbin wound with a coil, and between the I-shaped core tip and both C-shaped core tips. In a magnetic erasing head in which a dummy block is provided to form a gap and constitute a tape sliding surface together with each core, a notch corresponding to the dummy block is formed at the tip of each core, and a cutout corresponding to the dummy block is formed at the tip of each core. The length of the tip facing the tape sliding surface matches the track width, the bobbin and the dummy block are integrally molded from wear-resistant plastic, and each core and the dummy block protrude from the case. A magnetic erasing head characterized in that it is provided with a magnetic erase head. (2) The magnetic erasing head according to claim 1, wherein the bobbin integrally has a plate-like protrusion that defines the gap interval.