JPH0433599Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(Field of Industrial Application) The present invention relates to magnetic disk cassettes used in electronic devices such as word processors and personal computers, and particularly to improvements in lifters provided on the inner surface of the shell constituting the outer shell of the magnetic disk cassette. (Prior art and its problems) Normally, as shown in Figure 3, magnetic disk cassettes have a shell 11 made of a thin plate made of synthetic resin such as polyester or metal such as stainless steel on the inner surface of the shell 11 that constitutes the outer shell. A lifter 12 is attached. This lifter is inclined upward at a constant angle in the direction of rotation of the recording medium, and by elastically pressing a nonwoven fabric liner against the recording medium at its tip, it cleans the recording medium and prevents the media from running. Stabilization, uniform stabilization of head touch, etc. are achieved. However, the conventional lifter 12 is
As shown in b, it has a shape bent at a predetermined angle at approximately the center, and is attached by simply joining the lower surface of one end to the inner surface of the shell 11 with, for example, adhesive or adhesive. was. However, this bending of the lifter 12 is usually done at the same time as the lifter itself is die-cut from a thin sheet, or by cold-folding or hot-folding the die-cut lifter before joining it to the shell. However, in either case, it is difficult to set the angle accurately, and variations of around ±5° are unavoidable.
This has the disadvantage of adversely affecting the cleaning effect and electromagnetic conversion characteristics. Furthermore, it is desirable that the upper edge of the lifter's tip press against the recording medium with uniform pressure and be positioned at right angles to the rotational direction of the media. Not only is it difficult to bend the lifter, but it is also prone to misalignment during installation, resulting in variations in the contact pressure applied to the left and right sides of the upper tip of the lifter, which causes dropouts and other negative effects on the recording media. . Furthermore, after being attached to the shell 11, such a lifter loses its elasticity over time and the bending angle becomes small, which is a very serious problem both technically and practically. It was hot. In addition, if such a lifter is simply adhesively fixed to the flat inner surface of the shell, the adhesive used may protrude from the lifter, and dirt may adhere to it and form a solid substance, or the nonwoven fabric may become adhesive. This may deteriorate its cushioning properties, but these have been a cause of errors in recording media. Also, when this is made of stainless steel,
Because of its strong bending rigidity and repulsive force, there was a risk of damaging the recording medium. For this reason, as shown in FIG.
4, one end of an elastic piece 15 made of synthetic resin is attached to this, and the other end is extended diagonally upward and brought into pressure contact with the liner. According to this, although the disadvantages associated with bending and the use of adhesive in the previous example can be solved, this is because the contact area between the elastic piece 15 and the groove 14 is small.
It was not possible to prevent the elastic piece 15 from becoming fatigued during long-term use. In order to increase this contact area, it is necessary to deepen the groove 14, which requires making the shell 11 thicker, which has the disadvantage of increasing material costs. (Means for Solving the Problems) The purpose of the present invention is to provide a magnetic disk cassette equipped with a lifter that maintains an accurate angle without impairing the function of the magnetic media and can withstand long-term use. It is something to do. That is, the present invention provides a concave portion on the inner surface of the shell with a sloped bottom surface that rises in the direction of rotation of the recording medium, and a convex portion adjacent to this concave portion that has an upper sloped surface continuous with the sloped bottom surface. The present invention provides a magnetic disk cassette in which one end of a flat synthetic resin lifter is attached to both inclined surfaces. (Example) Next, this invention will be explained based on the example shown in FIGS. 1 and 2. Figures 1a and 1b show a first embodiment of this invention in a perspective view and a partial sectional view. is provided, the bottom of which forms an inclined bottom surface 3 that rises at a predetermined angle toward the rotational running direction of the recording medium, and the recess 2 has a wedge-shaped cross section. A convex portion 4 is provided adjacent to the rotation direction side of the concave portion 2, the upper portion of which is continuous with the inclined bottom surface 3,
An inclined surface 5 rising at the same angle as this is formed, and the cross-sectional shape of the convex part 4 is also wedge-shaped like the concave part 2. The formation of the concave portions 2 and the convex portions 4 can be done, for example, by providing corresponding portions in the mold cavity of the shell 1.
This is carried out by a known method such as integral molding by injection molding, compression molding, or the like. 6 is a lifter consisting of a flat plate made of synthetic resin with elasticity, and the tip of one end thereof is connected to the front wall 2 of the recess 2.
', and then its lower surface 7 is fixedly connected to the sloped (bottom) surfaces 3 and 5 continuously formed from the bottom surface of the recess 2 to the upper surface of the recess 4 using an adhesive or an adhesive. It is firmly held in the shell 1, and the other end extends obliquely upward, and its tip reaches the surface of the nonwoven fabric liner, which is elastically pressed against the surface of the recording medium. FIG. 2 shows another embodiment of this invention, and this magnetic disk cassette is different from the embodiment shown in FIG. 1 by providing protrusions 8, 8, . The small holes 9, 9... of the lifter 6 are drilled in advance at corresponding positions, and the small holes 9, 9... of the lifter 6 are fitted into the projections 8, 8.... Therefore, the lifter 6 is attached mechanically to the inclined surfaces 3 and 5, or after being attached, it is welded and fixed using an ultrasonic welding machine or the like. Although this embodiment has a slightly more complicated structure than the one shown in FIG. 1, it has the advantage that the positioning of the lifter 6 when it is attached to the shell 1 can be done easily and accurately. (Function of the invention) Next, with the structure shown in Figs. 1 and 5, the present invention using a lifter made of polyester with a thickness of 125μ, the conventional product, and the structure shown in Fig.
Made of 75μ and 125μ polyester and 50μ thick
The table shows the results of examining changes in lifter fatigue over time for conventional products using each type of stainless steel lifter.

[Table] In the test, the height of the tip of the lifter for each sample was maintained at 1 mm by applying a constant load for a predetermined period of time, which corresponds to the shell spacing on both sides of the magnetic disk cassette, and the height was determined after removing the load. The degree of settling was expressed by measuring and calculating the percentage of the weight before loading. From this, it can be seen that while the conventional products shown in Figure 4, especially the polyester products, show a remarkable degree of settling in the initial stage, there is almost no change in the product of the present invention, compared to the stainless steel products shown in Figure 4 and the conventional products shown in Figure 5. In addition to being able to obtain a product with less change over time,
Stainless steel products have strong bending rigidity and repulsive force, which can damage the recording media, but the product of this invention does not have that risk, so it can be provided with good performance at a low price. I understood. Furthermore, when the electrical characteristics of the same sample were measured using the average signal amplitude and modulation, no abnormality was observed, and it was found that there was no problem in practical use. (Effect of the invention) As explained above, the magnetic disk cassette of the invention has a recess on the inner surface of the shell with an inclined bottom surface that rises in the direction of rotation of the recording medium, and an adjacent recess adjacent to the recess. and providing a convex portion having an upper inclined surface continuous with the inclined bottom surface,
Since one end of a flat synthetic resin lifter is attached to both inclined surfaces, 1. The contact area between the lifter and the inner surface of the shell is large, and the lifter is firmly held at a predetermined angle, so it can be used for a long period of time. In addition to completely preventing the lifter from sagging during use, there is no need to increase the thickness of the shell, so less material is required. 2 The lifter presses the liner evenly, so
The liner comes into contact with the surface of the recording medium without strain, and cleaning and running of the recording medium are stabilized, as well as uniform and stable head touch. 3. Since the lifter is an elastic body without distortion, the drop in resistance due to changes over time is extremely small, and not only can it withstand long-term use, but there is no risk of damage to the recording media when using stainless steel products. It has remarkable effects such as

[Brief explanation of drawings]

Figures 1 and 2 show different embodiments of the present invention in terms of the lifter mounting structure.
is a perspective view thereof, and b is a longitudinal sectional view thereof. 3 to 5 relate to the conventional example, and FIG. 3 is a perspective view of the shell;
FIG. 4a is an enlarged perspective view of the lifter shown in FIG. 3, and FIG. 4b is a longitudinal cross-sectional view showing its mounting structure.
FIG. 5 is a longitudinal sectional view of a different conventional example. Explanation of the main symbols in the drawings, 1... Ciel, 2...
... recess, 3 ... inclined bottom surface, 4 ... convex section, 5 ... upper slope surface, 6 ... lifter.

Claims (1)

[Scope of utility model registration request] A recessed portion having an inclined bottom surface that rises in the direction of rotation of the recording medium is provided on the inner surface of the shell, and a convex portion having an upper sloped surface that is continuous with the inclined bottom surface is provided adjacent to this recessed portion. A magnetic disk cassette with one end of a flat synthetic resin lifter attached to the surface.