JPH0414656A - Tape tension detecting mechanism - Google Patents

Abstract

PURPOSE:To buffer the tentative excess tension of a tape by disposing an elastic supporting means for a tension detecting arm, a position detection means and a movement limiting means to one member supported elastically. CONSTITUTION:A leaf spring 68, a Hall sensor 74, a mechanism limiter 67 are disposed on one loading plate 63, and the loading plate 63 is supported elastically by a tensile spring 71. A tension detecting arm 70 is supported by the leaf spring 68 and moved up to a position balanced with the force detected by a tape tension detecting roller 7 and the quantity is detected by the Hall sensor 73 as the movement of the magnet 74. Thus, the tension detecting arm 70 is turned to the right integrally with the loading plate 63 so as to buffer the momentary excess tape tension.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a tape tension detection mechanism, and particularly to an arm type tape tension detection mechanism in a magnetic tape running device such as a magnetic recording/reproducing device.

[Conventional technology]

An example of this type of device that runs a tape by controlling tape tension is a magnetic recording/reproducing device (hereinafter referred to as a VTR) having a rotating drum equipped with a magnetic head.

FIG. 6 shows a schematic plan view of essential parts of an example of a tape running system after tape loading in a conventional VTR. 101 is a main chassis, 102 is a cassette half, 103 is a supply side reel, 104 is a take-up side reel, 105 is a magnetic tape, 106° 108.110, 111, 113, 11
4.116.119, 120, and 121 are tape guides for guiding the tape 105, 107 is a tension detection roller for detecting tape tension, and tos and tts are fixed heads. 112 is a rotating drum equipped with a magnetic head, and 117 is a capstan for conveying the tape 105 by pinching it between the pinch rollers 11B.

In the VTR on the side, the tape 105 is pulled out from the supply reel 103, and is passed through a tape guide 106, a tension detection roller 107, and so on. Tape guide 108. Fixed head 109. It wraps around the rotating drum 112 via tape guides 110, 111. Further, the tape 105 is attached to each tape guide 113, 114 . A fixed head unit 115° is conveyed via a tape guide 116 while being held between a capstan 117 and a pinch cooler 118. Furthermore, the tape 105 is connected to each tape guide 119, 120, 1
21, and is configured to be wound onto a take-up reel 104.

The tape tension of this VTR&:S is detected by the tension detection roller 107. An enlarged plan view of the main part of this mechanism is shown in FIG. 7, and an enlarged sectional view of the main part is shown in FIG.
As shown in the figure.

Reference numeral 160 denotes a loading lever, which is rotatably supported by a loading plate 163 and a shaft 162, which are shown broken away in FIG. 164 is a mechanical limiter (hereinafter abbreviated as mechanical limiter), which is connected to the tension detection arm 17o.
Spring support shaft 16 provided on the top (shown broken in the same figure)
The movement of the arm 170 is restricted by coming into contact with the arm 9 . 167 is a mechanical limiter shaft that limits the movement of the arm 170 by coming into contact with the tension detection arm 170. A Hall sensor stand 165 is screwed onto the main chassis 101, and a Hall sensor board 1 is mounted on the top surface.
66 is screwed down. A leaf spring 168 elastically supports the tension detection arm 170 via the spring support shaft 169. 173 is a magnet, which is fixed to the tension detection arm 170 with a screw. 174 is a Hall sensor (
Hall element), 175 is a spring plate provided with a leaf spring 168 and a mechanical limiter 164, and is screwed onto the loading plate 163. Reference numeral 176 denotes a limiter plate on which a mechanical limiter shaft 167 is erected, and is screwed onto the loading plate 163 described above. 177 is a rotation support shaft of the tension detection arm 170.

Here, a means for detecting the tape tension of the magnetic tape 105 will be explained. The tape tension is transmitted to the tension detection roller 107, giving the tension detection arm 170 a clockwise rotation moment in FIG. 6.7. On the other hand, a spring support shaft 169 provided on the tension detection arm 170 pushes a leaf spring 168 provided on the loading plate 163. Since the loading plate 163 is fixed by the loading lever 160, it applies a counterclockwise rotation moment to the tension detection arm 170 in FIG. 6.7. Eventually, the tension detection arm 170 moves to a point where the tape tension and the force of the leaf spring 168 are balanced. That is, the tension detection arm 170 rotates by an amount corresponding to the tape tension at that time. This amount of rotation is detected by a Hall sensor (element) 174 and a magnet. Tension detection arm 170
A magnet 173 for this purpose is provided above, and moves together with the tension detection arm 170. on the other hand,
A pole sensor 174 is mounted on the main chassis 101 via a Hall sensor stand 165 and a Hall sensor board 166.
is fixed. The pole sensor 174 is an element that generates a voltage in response to changes in the magnetic field, and can thereby detect the movement of the magnet 173 of the tension detection arm 1701.

This mechanism is configured to be able to detect tape tension. Furthermore, VTRL'$5 controls the tape tension based on this information.

Its block diagram is shown in FIG. Tension detection mechanism 1
80, the detected tape tension is converted into a voltage signal by the Hall sensor 174, amplified by the amplifier 182, and compared with the target tension voltage 183 by the comparator 184 to detect an error voltage.

Furthermore, the motor driver 185 outputs motor power according to the error voltage, and the reel motor 186 outputs motor power according to the error voltage.
A back torque is applied to the supply reel 187 to control tape tension.

By the way, the Hall sensor 174 that detects the movement of the tension detection arm 170 has conventionally been installed separately from the loading plate 163 via the Hall sensor stand 165 on the main chassis 101 which is fixed and does not move. It was getting worse.

The Hall element voltage output with respect to the amount of movement of the Hall sensor 174 and the magnet 173 has a relationship as shown by the dotted line in FIG. 10, which shows an example of the output characteristics. That is, the relationship has an extreme value when the north pole or south pole of the magnet 173 approaches.

Therefore, the tension detection arm 170 (7) 1113 is connected to each mechanical limiter 164.1 shown in FIGS. 7 and 8.
67, the area is limited to the area indicated by X in FIG.

Furthermore, the Hall element voltage used for electrical tension control is ■. In order to avoid malfunction of the tension control due to detection by the Hall sensor 1 and 4, the tension control is limited to the following.

[Problem to be solved by the invention]

However, in the above-mentioned conventional example, since a mechanical limiter mechanism 164 is provided to limit the movement of the tension detection arm 170, when an excessive tensile run is temporarily loaded on the tape, this tension is buffered. There is a risk that the tape will break or the mechanical limiter will be destroyed. If the latter mechanical limiter is destroyed, when the tension detection arm moves to the area x3 shown in FIG. 10, the Hall sensor 174 may malfunction and the reels 103 and 104 may run out of control due to tension control. In either case, there was a possibility that the VTR running system and tape would be seriously damaged.

The present invention has been made in view of the problems of the conventional examples as described above, and even if excessive tension is temporarily applied to the tape, it can buffer this and prevent the damage as described above. The purpose is to provide the means.

(Means for Solving the Problem) Therefore, in the present invention, in a control device for controlling tape tension and running the tape, the tape guide means for detecting the tape tension and one end thereof are provided. a tape tension detection arm that is rotatably supported and has a tape tension detection guide means at the other end; an elastic support means for biasing the arm in one rotation direction;
The elastic supporting means, the position detecting means, and the movement limiting means have the same elasticity. The above object is achieved by configuring the tape tension detection mechanism to be disposed on the support member.

(Function) With the configuration of the tape tension detection mechanism as described above,
Even if excessive tension is temporarily applied to the tape, the elastic supporting means acts to prevent damage to the various parts.

〔Example〕

The present invention will be explained below based on examples.

FIGS. 1 and 2 are a plan view and an enlarged cross-sectional view of the essential parts of an embodiment of the tape tension detection mechanism according to the present invention, and FIG. 3 shows a VTR equipped with this tape tension detection mechanism. A schematic plan view of the tape running system at the time of completion of loading is shown, and the same (equivalent) components as in FIGS. 6 to 8 of the conventional example are represented by corresponding symbols excluding 100-digit numbers.

(Configuration) 1 is the main chassis, 2 is the cassette half, 3 is the supply side reel, 4 is the take-up side reel, 5 is the magnetic tape, 6, 8,
10, 11, 13, 14° 16. 19, 20. 21 are respective tape guides for guiding the tape 5, 7
1 is a tension detection roller as a tension detection guide means, 9.15 is each fixed head, 12 is a rotating drum equipped with a magnetic head, and 17 is a pinch roller 1 for holding the tape 5.
This is a capstan for holding and conveying with 8. The tape 5 is pulled out from the supply reel 3 and guided through the tape guide 6.
, tension detection roller 7, tape guide 8. Fixed head9. Rotating tram 1 through each tape guide 10.11
Wrap around 2. Further, the tape 5 is connected to each tape guide 13.
゜14, fixed head unit 15. The tape is conveyed through a tape guide 16 while being held between a capstan 17 and a pinch roller 18 . And each tape guide 19, 2
It is wound onto the take-up reel 4 via a wire of 0.21.

(Tensilene Detection Mechanism) Next, the tension detection mechanism according to the present invention will be described based on FIG. 1, which is an enlarged plan view that best shows the characteristics, and FIG. 2, which is an enlarged sectional view.

Reference numeral 60 denotes a loading lever, which has an arc-shaped shaft 79 centered on the rotation support shaft 77 of the tension detection arm 70 after loading is completed. Further, a shaft 62 is provided on the loading plate 63, and the arc-shaped groove 79
It is mated with. Also, 78 is the rope ink plate 6
The fixing point 7 at the other end is rotated so that the plate 63 is rotationally biased by a tension (coil) spring 71 with a shaft provided on the lower surface of the plate 63.
From 2 onwards, tension is applied. 64 is a mechanical limiter (hereinafter abbreviated as mechanical limiter) as a movement limiting means;
Spring support shaft 6 provided on the tension detection arm flow
9 limits the movement of the arm 70. A mechanical limiter shaft 67 limits the movement of the arm 70 by coming into contact with the tension detection arm 70. , 65 are Hall sensor stands screwed onto the rope ink plate 63, and a Hall sensor board 66 is screwed onto the top surface.

A leaf spring 68 elastically supports the tension detection arm 70 via the spring support shaft 69 mentioned above.

Reference numeral 72 denotes a shaft provided on the main chassis l, which serves as a fixed end of the tension spring 71. , 73 are fixed to the four-tension detection arm 70 with magnets. 74 is a Hall sensor (
Hall element), 75 is the leaf spring 68. A mechanical limiter 64 is a spring plate to which is screwed, and is disposed on the loading plate 63. 76 is a limiter plate on which a mechanical limiter shaft 67 is erected, and is disposed on the loading plate 63.

77 is a rotation support shaft of the tension detection arm 70.

The operating principle of the tension detection mechanism is the same as that in the conventional example described above, and therefore, repeated explanation will be omitted here.

The features of this embodiment include a 68° leaf spring and a Hall sensor 74. A mechanical limiter 67 is disposed on one loading plate 63, and this loading plate 63 is elastically biased and supported in the counterclockwise direction in FIG. 1 by a tension spring 71. Figure 1 shows these operations.

This will be explained based on FIGS. 4 and 5. FIG. 1 shows the case of the same cypress as in the conventional example shown in FIG. 7, that is, a state in which the tension control is normally operating.

The tension detection arm 70 is supported by a leaf spring 68,
It moves to a position balanced with the force detected by the tape tension detection roller 7, and this amount is detected by the Hall sensor 73 as the movement of the magnet 74. This corresponds to the range of X in FIG. Next, in FIG. 4, a relatively large tape tension is applied to the tension detection arm 70, and whether this arm 70 or the rope ink plate 63
It shows the state when it comes into contact with the mechanical limiter shaft 67 disposed above. This is the part indicated by point A in FIG. In this state, the loading plate 63 is
A shaft 62 erected on the lower surface of the plate is supported by a tension spring 71 in contact with an end of an arcuate groove 79 of the loading lever 60 .

FIG. 5 shows a state in which even more excessive tape tension is applied. The tension detection arm 70 is pulled by the tape tension and rotates to the right in the figure. By the way, since this arm 70 is in contact with the mechanical limiter shaft 67, it transmits a force to rotate the loading plate 63 clockwise. Then, the shaft 62 erected on the lower surface of the loading plate 63 overcomes the elastic reaction force of the tension spring 71 and separates from the end of the arcuate groove 79 . Accordingly, the tension detection arm 70 further rotates clockwise together with the loading plate 63, thereby being able to buffer the instantaneous excessive tape tension.

This state corresponds to the range x2 * Therefore, the Hall element voltage VC maintains the state at point A in FIG. Therefore, the Hall sensor 74 only operates in the range of X+ and does not malfunction in the range of x3.

(Other Embodiments) In this embodiment, the loading plate 63 is elastically biased and supported by a tension coil spring, but it goes without saying that this may be replaced with a torsion spring or the like.

Furthermore, similar effects can be obtained by replacing this with an elastic member such as a sponge or rubber material.

Further, in this embodiment, the spring support mechanism, mechanical limiter mechanism 64, and Hall sensor 74 are arranged on the loading plate 63, but even when there is no need for loading, they are arranged on this type of elastically supported member. Of course, the same effect can be obtained by doing so.

Furthermore, in this embodiment, the position of the tension detection arm 70 is detected using the magnet 73 and the Hall element 74, but the same effect can be obtained even if the position is detected using a magnet-MR element. can get.

(Effects of the Invention) As explained above, according to the present invention, by arranging the elastic support means, the position detection means, and the movement restriction means of the tension detection arm on one elastically supported member, It has the effect of buffering the temporary excessive tensile strength of the tape.

[Brief explanation of drawings]

FIG. 1 is a plan view of an embodiment of the tension detection mechanism of the present invention, FIG. 2 is an enlarged sectional view of the main part of FIG. 1, and FIG.
FIG. 4 is a plan view of the tape running system of the VTR of this embodiment.
Figure 1 is a diagram equivalent to when a relatively large tension is applied to the tape, Figure 5 is a diagram equivalent to Figure 1 when an excessive tension is applied to the tape, and Figure 6 is a diagram of a conventional tape VTR running system. A plan view of an example, FIG. 7 is an enlarged view of the main part of the tape tension detection mechanism in FIG. 6, FIG. 8 is an enlarged sectional view of the main part of FIG. 7, and FIG. 9 is a tape tension control block diagram. FIG. 10 is an example of a Hall element voltage characteristic diagram. 5 ------- Magnetic tape 66 ------- Hall sensor board 67 ---- Mechanical limiter shaft 6 B ------- Leaf spring 69 ------- Spring support shaft 70 ------- -Tension detection arm 71---
tension coil spring

Claims (1)

[Claims] A control device for running a tape by controlling tape tension, comprising: a tape guide means for detecting the tape tension; and a tape tension detection arm rotatably supported at one end and provided with a tape tension detection guide means at the other end. and elastic support means for biasing the arm in one rotation direction, position detection means for detecting the movement of the arm, and movement limiting means for restricting the movement of the arm. A tape tension detection mechanism characterized in that an elastic support means, the position detection means, and the movement restriction means are arranged on the same elastic support member.