JPH0454618Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a head touch mechanism for bringing the magnetic tape into contact with a magnetic head in a so-called cassette tape in which the magnetic tape is housed in a box-shaped case.

[Conventional technology]

As shown in Fig. 4, a so-called linear tracking type audio cassette tape has a pair of hubs 2, 2 that are pivotally supported in a box-shaped case 1, and a magnetic tape 3 is wound around these hubs 2, 2. This is what I did. The magnetic tape 3 can be wound and rewound by loading the case 1 into a drive (not shown, the same applies hereinafter) of a cassette tape recorder.
When loading the drive, the magnetic head 5 is inserted into the case 1 through the magnetic head insertion window 4 on the front surface, and the head 5 contacts the magnetic tape 3 running on the front surface of the case 1, thereby recording. Or playback takes place.

In conventional cassette tapes of this type, a head touch mechanism as shown in FIG. 5 is used to bring the magnetic tape 3 into contact with the magnetic head 5. This head touch mechanism has a non-woven fabric in the center of a leaf spring 6 whose both ends are supported by pins 9, 9.
A flat pad 7 made of rabbit hair, wool, etc. is attached.

In the above-mentioned conventional head touch mechanism, the leaf spring 6 that supports the pad 7 is made of a thin flat spring metal plate with both ends bent backward at an angle of approximately 90 degrees, and this bent portion is connected to the pins 9 and 9. It is supported by

[Problem that the invention attempts to solve]

However, this conventional head touch mechanism has the following problems.

First, since the leaf spring 6 is in the form of a flat plate, both ends supported by the pins 9 have little freedom in tilting in the thickness direction, and as shown by arrows in FIG. When pressure is applied to the leaf spring 7 with a vertical shift, the leaf spring 6 is twisted accordingly. Therefore, a repulsive force corresponding to the amount of twist is applied to the pad 7, and the biased pressure is directly applied to the magnetic tape 3. Moreover, the above-described twisting reduces the elasticity of the leaf spring 6 in other directions, making it impossible to utilize the elasticity effectively.

Second, when the wall thickness of the leaf spring 6 is reduced, its rigidity is insufficient, so that sufficient elasticity may not be obtained at the center far from the pins 9, 9, which are the fulcrums. On the other hand, if the wall thickness of the leaf spring 6 is increased,
Due to the increase in weight associated with this, the movement of the pad 7 becomes worse.

This idea was made to solve the above-mentioned problems with the conventional tape cassette head touch mechanism.It can effectively absorb uneven vertical pressure applied to the pad, and even with a thin plate spring, the pad can be easily fixed. It is an object of the present invention to provide a head touch mechanism which can obtain sufficient elasticity at the attached central part.

[Means to solve the problem]

The structure of this invention will be explained with reference to the reference numerals in FIGS. 1 to 3. Both ends of the leaf spring 16 are supported by pins 19, 19 set in the case 11, and a pad 17 is placed in the center of the pins 19, 19. Attach. This pad 17 is connected to the magnetic head insertion window 1 of the case 11.
The pad 17 is placed toward the outside of the magnetic head insertion window 14 from the back side of the magnetic tape 13 passing through the magnetic head insertion window 14.

And the leaf spring 16 that hits the pins 19, 19
The entirety of both ends of is curved so that the side surface has an arcuate shape with a protrusion toward the back side.

[Effect]

In this head touch mechanism, as shown in Fig. 2, when a large pressure difference occurs between the top and bottom, the leaf spring 1
Since both ends of the leaf spring 6 are entirely curved and the side surface is formed in an arc shape, the leaf spring 16 tilts as shown by the arrow in response to this pressure difference. Therefore, leaf spring 1
Since the pad 17 tilts in response to the unevenness of the pressure without substantially twisting the magnetic tape 6, the repulsive force due to the twisting does not act on the magnetic tape 13, and the pressure difference is absorbed.

In addition, since both ends of the leaf spring 16 are curved, the rigidity of these parts is high, and even if the leaf spring 16 is thin, a relatively large elasticity can be obtained at the center of the flat leaf spring 16. You will be able to do it.

〔Example〕

Next, an embodiment of this invention will be described with reference to FIGS. 1 to 3.

A magnetic head insertion window 14 is provided at the front of the case 11, and a shield plate 2 made of a metal plate is installed inside the window 14.
0 is installed upright, and a pair of pins 1 are installed on both sides of this front side.
9 and 19 are erected. This pin 19,19
Both ends of the leaf spring 16 are supported so as to hang over the leaf spring 16, and a cubic pad 17 made of nonwoven fabric, rabbit hair, wool, etc. is attached to the center of the leaf spring 16.

The magnetic tape 13 passes through the front surface of the pad 17, and the magnetic tape 13 is placed between the pad 17 and the magnetic head 21 inserted through the magnetic head insertion window 14.
3 is caught.

The leaf spring 16 is made of an elastic, thin and elongated metal plate such as a phosphor bronze plate.
Bend it once and hang this part on the pins 19, 19 for support. Note that when the leaf spring 16 is in a straight state with no load applied, the distance between the bent pieces 22 at both ends is set to be slightly longer than the outer distance between the pins 19, 19.

Furthermore, both ends of the leaf spring 16 are curved so that the central part on the back side is convex. As shown in FIG. 3, when the distance L from the bent pieces 22, 22 to the side surface of the pad 17 is approximately 5 mm, the length l of the curved portions 18, 18 is 1/3 to 2/3 of that. The degree is appropriate, especially around 1/2. In addition, the curved portion 1
The radius of curvature of 8 and 18 is 2.5 mm when the width of leaf spring 16 is 2.5 mm.
In the case of front and rear, a range of 2 to 10 mm is good, especially 3 to 6 mm.
mm is better.

[Effect of idea]

As explained above, according to the head touch mechanism of this invention, when a pressure difference occurs between the top and bottom of the pad 17, the pad 17 tilts in response to the uneven pressure without twisting the leaf spring 16. The repulsive force of the leaf spring 16 is not biased, and the pressure difference is absorbed. Therefore, even under such abnormal conditions, the magnetic tape 13 can be pressed onto the magnetic head 21 with uniform pressure.

Furthermore, even if the plate spring 16 is thin, a relatively large elasticity can be obtained at the center of the flat plate spring 16, which has the effect of compensating for the lack of elasticity due to thinning of the plate.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view of a main part of a head touch mechanism for cassette tape showing an embodiment of this invention, FIG. 4 is a plan view of the inside of a case showing a conventional example of a head touch mechanism for cassette tape, and FIG. 5 is a perspective view of the periphery of the pad of the same mechanism. FIG. 11... Case, 13... Magnetic tape, 16...
...Plate spring, 14...Magnetic head insertion window, 17...
Patsudo, 19...pin.

Claims (1)

[Scope of utility model registration request] A pad 17 is attached to the center of a leaf spring 16 whose both ends are supported by pins 19, 19 set up in the case 11, and the pad 17 is inserted from the back side of the magnetic tape 13 passing through the magnetic head insertion window 14 of the case 11. In a magnetic tape head touch mechanism in which the magnetic tape head is placed facing outside of the magnetic head insertion window 14, both ends of the leaf spring 16 that contact the pins 19, 19 are entirely shaped so that the side surface shape is an arc convex toward the back side. A magnetic tape head touch mechanism characterized by a curved structure.