JPH03216842A - Driving device for magnetic tape running - Google Patents

Abstract

PURPOSE:To eliminate a need of a large-sized capstan rotating motor to make a device light-weight and small-sized by eliptically oscillating the surface, which comes into contact with a magnetic tape, of a capstan to directly run the magnetic tape. CONSTITUTION:A fixed capstan 21 and a freely rotatable pinch roll 22 are arranged on the running course of a magnetic tape 20 with the magnetic tape 20 between them, and a part facing the magnetic tape 20 of the capstan 21 is made of an elastic body 25, and a means (piezoelectric ceramics) 24 which generates a progressive wave in this elastic body 25 is provided. When the progressive wave is generated in the elastic body 25 of the capstan 21 coming into contact with the magnetic tape 20, contact points to the magnetic tape 20 on the surface of the elastic body 25 are elliptically oscillated to run and drive the magnetic tape in the direction opposite to the advance direction of the progressive wave, and the magnetic tape 20 is run without rotating the capstan 21 by a running motor. Thus, the device is made light-weight and small- sized.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a drive device for running a magnetic tape in a video tape recorder or the like.

Conventional technology In recent years, video tape recorders have become widespread, and portable video tape recorders have been attracting attention recently, and the most important issues are how to make them light, small, and energy efficient. Ru. Therefore, various studies have been conducted to make the running system, which is the internal mechanism, lighter, thinner, and smaller.

An example of a tape running system of a conventional video table recorder will be explained with reference to FIGS. 5 and 6. In FIG. 5, a magnetic tape 3 is pulled out from a supply reel 1 and a take-up reel 2 located inside the video cassette tape. This magnetic tape 3 passes from the supply reel 1 via the back tension post 4 to the full-width erasing head 5, contacts a rotating cylinder 7 carrying a rotating head, contacts an audio erasing head 8 and an audio control head 9 - a cab stun 10 It is configured to be wound onto a winding roll 2 via a pinch roller 11 and a pinch roller 11. Further, as shown in detail in FIG. 6, a tape running electric motor 13 is attached to the lower part of the chassis section 12 to which the capstan 10 and the pinch roller 11 are attached, with the capstan 10 serving as a rotating shaft. It is being

The operation of the magnetic tape running system configured as described above will be explained next. The magnetic tape 3 pulled out from the video cassette tape is given an appropriate tension by the back tensioner post 4, and then the tape running electric motor 13 The magnetic tape 3 is moved by the rotation of the driven capstan 10 and the pressure applied by the pinch roller 11, and recording and reproduction are performed by the rotating cylinder 7.

Problems to be Solved by the Invention However, in the above configuration, the capstan 10
Since the tape running electric motor I3 for driving the tape running motor I3 is large in size, there is a problem in that it is not suitable for video tape recorders, such as portable video tape recorders, where lightness and miniaturization are important.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, it is an object of the present invention to provide a magnetic tape running drive device that can be made lighter and smaller.

Means for Solving the Problems In order to achieve the above object, the present invention disposes a fixed cab stun and a rotatable pinch roller on the traveling path of the magnetic tape so that the magnetic tape is sandwiched between them. It is characterized in that the portion of the stun facing the magnetic tape is made of an elastic body, and a means for generating a traveling wave is provided in the elastic body.

In addition, a rotatable capstan and a rotatable pinch roller are arranged in the running path of the magnetic tape so that the magnetic tape is sandwiched between them, and the pinch roller is pressed against the portion of the pinch roller other than the portion that contacts the magnetic tape. An elastic body may be provided and a means for generating a traveling wave in this elastic body may be provided.

According to the above structure of the present invention, traveling waves are formed in the elastic body of the capstan that comes into contact with the magnetic tape.
Each point of contact with the magnetic tape on the surface of this elastic body vibrates elliptically, causing the magnetic tape to travel in the opposite direction to the traveling direction of the traveling wave, allowing the magnetic tape to travel without rotating the cab stan with the travel motor. be able to.

In addition, a traveling wave is generated in the elastic body in contact with the pinch roller,
The magnetic tape can be similarly run by rotating the pinch roller by elliptical vibration at the point of contact with the pinch roller.

Embodiment A magnetic tape running drive device according to a first embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

In FIG. 1, a fixed capstan 21 is arranged so as to pinch the magnetic tape 20 between it and a rotatably supported pinch roller 22. This cab stan 21 has a partially cylindrical elastic body 25 attached to the outer peripheral surface of a fixed cylindrical or partially cylindrical support shaft 23 via two layers of piezoelectric ceramics 24. The side surface is configured to be in contact with the magnetic tape 20. In each layer of the two layers of piezoelectric ceramics 24, polarizations 24a and 24b with opposite directions are formed alternately in the circumferential direction, and between the two layers of piezoelectric ceramics 24 and 24, the polarization i24a and 24b is 1/4 The phase is shifted by a period. In addition, two-layer piezoelectric ceramics 24
The structure is such that AC voltages of arbitrary frequencies, which are 90 degrees out of phase with each other, can be applied from AC power supplies 26a and 26b between both sides of each side.

In the above configuration, when the magnetic tape 20 is run, AC voltages having a phase difference of 90° are applied to the two layers of piezoelectric ceramics 24a and 24b by AC power sources 26a and 26b. Then, elongation strain and contraction strain occur alternately in each of the polarizations 24a and 24b of the two-layer piezoelectric ceramic 24, so that the elastic body 25 exhibits (a) to (a) in FIG.
A traveling wave is excited as shown in e). This elastic body 25
If we focus on one point on the surface of , that point is a, b, c,
It moves as d, a, etc., and when these movements are combined, it vibrates in an elliptical trajectory in the opposite direction to the traveling direction of the traveling wave, as shown in Fig. 3. Thus, the magnetic tape 20, which is pressed against the surface of the capstan 21 by the pinch roller 22, is directly driven and travels in the direction opposite to the traveling direction of the traveling wave by the elliptical vibration of the elastic body 25 at each contact point. become.

As described above, according to this embodiment, unlike the conventional capstan, a tape running electric motor is not required, and the magnetic tape is directly driven by elliptical vibration, so that the magnetic tape running system can be downsized.

Next, a magnetic tape running drive device according to a second embodiment of the present invention will be explained with reference to FIG.

In FIG. 4, numeral 31 is a rotatably supported capstan, and 32 is a rotatable pinch roller as in the conventional case, which is arranged so as to pinch the magnetic tape 30 between the capstan 3 and the pinch roller 32. has been done. A drive unit 36 is disposed on the back of the pinch roller 32 and is configured by attaching a plate-shaped elastic body 35 to one side of a support 33 via two layers of piezoelectric ceramics 34. The surface is pressed against the outer peripheral surface of the pinch roller 32. Although not shown, the piezoelectric ceramics 34
is configured to apply an alternating current voltage of any frequency from an alternating current power supply.

In the above configuration, when the magnetic tape 30 is run, when voltages with different phases are applied to the piezoelectric ceramics 34, a traveling wave is excited in the elastic body 35 by the expansion and contraction action of each piezoelectric ceramic 34, and a traveling wave is excited at each point on the surface of the elastic body 35. Since the elliptical vibration occurs, the pinch roller 32 in contact with the surface of the elastic body 350 is driven to rotate, and the capstan 31
The magnetic tape 30, which is being pinched between the pinch roller 32 and the pinch roller 32, runs.

As described above, according to this embodiment, as in the first embodiment, the electric motor for rotating the cab stun 31 is eliminated, and the pinch roller 32 is rotated by the block-shaped drive unit 36 by elliptical vibration. It is possible to downsize the tape running system.

Although piezoelectric ceramics are used in the above embodiments, other electrostrictive elements that generate distortion due to changes in applied voltage may be used.

Effects of the Invention According to the present invention, the surface of the cab stan that comes into contact with the magnetic tape vibrates elliptically, making it possible to directly run the magnetic tape, which eliminates the need for the conventional large electric motor for rotating the cab stan, making it lightweight. , it is possible to achieve downsizing and efficient driving. In addition, there is no need to use magnetism as a drive source, and the influence of magnetic noise can be eliminated, resulting in great effects.

Further, the same effect can be obtained by generating elliptical vibration on the surface of the elastic body that comes into contact with the pinch roller to rotate the pinch roller.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a schematic configuration of a magnetic tape running drive device according to a first embodiment of the present invention, FIG. 2 is an explanatory diagram of a traveling wave excited in the elastic body, and FIG. 3 is an illustration of a traveling wave excited in the elastic body. An explanatory diagram of elliptical vibration on the surface, FIG. 4 is a perspective view showing the schematic configuration of a magnetic tape running drive device in a second embodiment of the present invention, and FIG. Perspective view FIG. 6 is a perspective view of the main parts. 20, 30 2 1, 31 22, 32 23 24, 34 25, 35 3 3 --1--・36--11 Magnetic tape cab stamp pinch roller support shaft piezoelectric ceramic elastic body support drive unit.

Claims (2)

[Claims] (1) A fixed capstan and a rotatable pinch roller are arranged in the running path of the magnetic tape so that the magnetic tape is sandwiched between them, and the part of the capstan that faces the magnetic tape is made of an elastic material. A magnetic tape running drive device characterized in that the elastic body is provided with means for generating a traveling wave. (2) A rotatable capstan and a rotatable pinch roller are arranged in the running path of the magnetic tape so that the magnetic tape is sandwiched between them, and the pinch roller is pressed against the part other than the part that contacts the magnetic tape. 1. A drive device for running a magnetic tape, characterized in that an elastic body is disposed in the elastic body, and a means for generating a traveling wave is provided in the elastic body.