JPS60254446A - Slant pole of magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To hold the normal run of a magnetic tape so as to reduce the frictional force, by constituting a rotary section which is smaller than the width of the magnetic tape and a fixed section which controls the movement of the tape so that the tape cannot be moved in undesired directions by the rotary section at the section where the magnetic tape is wound. CONSTITUTION:A slant pole 4 is equipped with a rotary section 4a having a width S smaller than the width A of a magnetic tape 1. The rotation of the rotary section 4a is made around the axis of the slant pole 4 and its rotating direction is not normal to the running direction of the magnetic tape 1. This is because the slant plate 4 is standed under an inclined condition. Therefore, when force being applied to a minor area of the magnetic tape 1 is considered, the force in the running direction of the magnetic tape 1 and the force in the rotating direction of the rotary section 4a are applied to the area and the upward force of the slant pole 4 acts on the magnetic tape 1. Therefore, the width B of the rotary section 4a is made smaller than that A of the magnetic tape 1 to prevent the upward movement of the magnetic tape 1.

Description

[Detailed description of the invention] [Field of application of the invention] The present invention relates to a slant ball for a magnetic recording/reproducing device.

[Background of the invention]

^3 Figure shows a slant ball in a conventional magnetic recording/reproducing device provided in a loading mechanism.

A leader for spreading a magnetic tape 1 pulled out from a cassette (not shown) onto a drum cylinder 2 has a roller 3 erected perpendicularly to the reference plane and a slant ball 4 erected diagonally. This slant ball 4 is used to change the incident angle and exit angle of the magnetic tape 1 as shown in FIG.

As shown in Figure 4, the tape tension runs before and after the slant ball 4 are T1 and T, the M friction coefficient between the magnetic tape 1 and the slant ball 4 is μ, and the winding of the magnetic tape 1 around the slant ball 4 is at an angle. When is θ, the following formula holds true.

T,=T,・eμθ These frictional forces increase tape tension.

This causes serious problems in running the magnetic tape 1, such as the occurrence of stick slips. In recent years, with the use of metal tapes or vapor-deposited tapes, and with the decrease in allowable tensile stress due to thinning of magnetic tapes, the above-mentioned problems regarding frictional force have become increasingly serious.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned points, and its object is to provide a slant ball for a magnetic recording/reproducing device that reduces the cost of magnetic tape by $6.

[Summary of the invention]

In this book, the magnetic tape is wound around a rotatable part with a width smaller than the width of the tape, and the rotation of the rotatable part applies an undesired force to the magnetic tape to change the direction. It is characterized by reducing the frictional force between it and the magnetic tape without changing it.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the slant ball 4 is connected to the magnetic tape 1.
The rotating part 4a has a width B that is smaller than the width A of
Ru. The upper and lower fixed parts of the slant ball 4 are connected by a central shaft 4b, and the rotating part 4a is rotatable with respect to the central shaft 4b. The fixed part and rotating part 4a of the slant ball 4 have the same outer diameter, and the magnetic tape 1 is wound around both.

The friction coefficient of the rotating part of the slant ball 4 is μm, the friction coefficient of the fixed part is μ2, and the tape tension of the magnetic tape 1 before and after the slant ball 4 is T, , I
ll, the following equation holds true.

The friction coefficient μm is very small compared to the friction coefficient μmushroom, so the tension T! The value of will also become smaller.

Incidentally, the rotation of the rotating portion 4a is performed around the axis of the slant ball 4, and is not perpendicular to the running direction of the magnetic tape 1. This is because the slant ball 4 is established at an angle. Therefore, considering the force in the minute area of the magnetic tape 1, the force in the running direction of the magnetic tape,
A force in the rotational direction of the rotating portion 4a acts, and eventually an upward force of the slant ball 4 acts on the magnetic tape 1. For this reason.

In order to prevent the magnetic tape 1 from moving upward, the rotating part 4
The width B of a is made smaller than @A of the magnetic tape 1, and a force is applied to the fixed portion of the slant ball 4. Therefore, the magnetic tape 1 rotates while sliding on the rotating portion 4a and advances in the running direction shown by the arrow in FIG.

The width B of the rotating portion 4a described above is 1 of the width A of the magnetic tape 1.
It is good to choose a value of /2 or less, but it is best to confirm the details through experiments before deciding.

〔Effect of the invention〕

As explained above, the present invention includes a rotating part smaller than the width of the magnetic tape in the part where the magnetic tape is wound, and a fixed part that acts to prevent the magnetic tape from moving in an undesired direction due to the rotating part. Because of this configuration, a slant ball can be obtained in which the normal running of the magnetic tape is maintained and the slanting force is reduced.

[Brief explanation of drawings]

FIG. 1 is a front view of a slant ball according to an embodiment of the present invention, FIG. 2 is a front view showing a state in which magnetic tape is wound around the slant ball shown in FIG. 1, and FIG. 3 is a front view of a conventional slant ball. Magnetic recording and reproducing device. 4 is a plan view of the slant ball of FIG. 3, and FIG. 5 is a front view of the slant ball of FIG. 3. 1...Magnetic tape, 2...Drum cylinder, 4...Slant ball, 4a...
...Rotating part.

Claims (1)

[Claims] In a slant ball of a magnetic recording/reproducing device that winds a magnetic tape diagonally to change the running direction, the winding portion of the magnetic tape of the slant ball has a width smaller than the width of the magnetic tape. It is characterized by comprising a rotating part that rotates as the tape runs, and a fixed part that applies a frictional force to the magnetic tape to prevent the rotating part from moving the magnetic tape in the axial direction of the slant ball. Slant ball is a magnetic recording and reproducing device.