JPS6215880Y2 - - Google Patents

Description

[Detailed description of the invention] The invention is applicable to, for example, a video tape recorder (hereinafter referred to as
Abnormalities in the tape due to the inertial force of the take-up reel tend to occur when the power is turned off while the magnetic tape (hereinafter simply referred to as tape) is running at high speed, especially in tape feed control devices used in VTRs. The present invention aims to provide a tape feed control device that can apply a tape tension or prevent tape deflection.

The tape wound around the outer circumferential surface of the tape guide drum must travel around the tape guide drum in an optimal contact state, but changes in the winding amount of the tape wound around the supply reel,
Alternatively, if the running condition changes for some reason, the tape tension of the tape changes.
For this reason, for example, in the case of a VTR, so-called skew distortion may occur on the screen, degrading the image quality.

Therefore, in the case of VTRs, etc., a tension regulator device using a band brake or the like is installed to control fluctuations in the tape tension of the tape on the supply side and keep the above-mentioned tape tension constant. ing.

By the way, when the tape is running at high speed, it is necessary to release the brake band etc. associated with the tension regulator device from the supply side reel stand so that no load is applied to the tape being wound from the supply reel to the take-up reel. The tape is run at high speed in a state where the tape is running at high speed, but if the power to drive the VTR is cut off due to a power outage etc. during this high speed run, the brake band is released from the supply side reel stand. At that moment, the plunger of the solenoid working on the reel no longer maintains its state, which may apply a brake to the supply reel stand. When this happens, when the tape is being wound quickly, an abnormally high tension is applied to the tape due to the inertial force of the take-up reel, and when the tape is being rewound quickly, an abnormally high tension is applied to the tape. In this case, the tape becomes slack due to the inertial force of the take-up reel. As a result, there are disadvantages in that a part of the tape may be stretched, or when the power is turned on again, the tape may be pressed against the flange provided on the tape guide pin, causing damage to the tape.

The present invention has been proposed to eliminate these conventional drawbacks.

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

FIG. 1 is a schematic plan view showing the operating state of the tape feed control device when the tape is being fed at a constant speed, and FIG. 2 is a schematic plan view showing the operating state of the tape feeding control device when the tape is being fed at high speed.

In FIG. 1, a tape cassette (not shown)
A brake band 2 as a brake means is mounted on the outer peripheral surface of the supply side reel stand 1 on which the supply reel is mounted. One end of the brake band 2 is fixed to the chassis of the VTR, and the other end is locked to a part of a rotating arm 4, which is a brake link rotatably mounted on a first support shaft 3.

A tension regulator arm 6 is rotatably attached to the first support shaft 3 for applying a predetermined back tension to the tape 5 wound around the outer peripheral surface of the tape guide drum. . A tape guide pin 6a for guiding the tape 5 is implanted at one end of the tension regulator arm (tension arm) 6. A spring 7 is stretched between the tension regulator arm 6 and the rotation arm 4 to connect them. In addition, between the tape guide pin 6a on the upper surface of the tension regulator arm 6 and the first support shaft 3, there is a first support for preventing the pressing protrusion 4a formed on the rotation arm 4 from rotating. A stopper 8 is formed to protrude.

At a lower position of the tension regulator arm 6, a rotary lever 9 is rotatably supported on the first support shaft 3. This rotating lever 9 is
It is divided into two parts around the above-mentioned support shaft 3,
One first lever part 10 has a V-shaped notch 10a, and the other second lever part 11 has a second stopper formed to protrude from the lower surface of the tension regulator arm 6. A through hole 11a into which a hole 12 is inserted is formed respectively. Inside the notch 10a of the first lever section 10 is a control plate for operating the rotary arm 4, which is a brake link that slides in the direction of arrow A or B in FIG. 1 during loading or unloading, respectively. A protrusion 13a planted on the slide plate 13 is inserted.

Furthermore, on the tension regulator arm 6 between the tape guide pin 6a and the first support shaft 3, there is a spring 14 that elastically biases the tension regulator arm 6 in the right direction in FIG.
is provided.

On the other hand, a self-holding solenoid 16 including a plunger 15 is fixed near the first support shaft 3 . This self-holding solenoid 16
functions to release the brake band 2 from the supply reel stand 1 when the tape 5 is running at high speed, and even if the power is cut off during the high speed run, the brake band 2 is released from the supply side reel stand 1. It works to maintain the released state.

At the tip of the plunger 15 of this self-holding solenoid 16, there is a long hole 1 formed in a pressing rod 18 that can freely rotate around a second support shaft 17.
A shaft 20 inserted into 9 is attached.

Note that the elongated hole 19 bordering on the second support shaft 17
A compression spring 21 is stretched between one end of the pressing plate 18 on the opposite side and the self-holding solenoid 16. Further, at the other end of the pressing plate 18,
A pressing portion 18a is provided for pressing one end of the rotating arm 4 during the suction operation of the plunger 15 and rotating the rotating arm 4 in the counterclockwise direction in FIG. 1 about the first support shaft 3. It is being

The operation of the present invention having the above configuration will be explained.

First, the operation of the tape feed control device when the tape runs at a constant speed will be described.

When the slide plate 13 moves in the direction of arrow A in FIG. 1 while the tape is being pulled out from inside the tape cassette, the protrusion 13a of the slide plate 13 presses the notch 10a of the rotating lever 9. The rotating lever 9 rotates clockwise in FIG. 1 about the first support shaft 3. As shown in FIG. Therefore,
The through hole 11a formed in the second lever part 11 of this lever 9 presses the stopper 12 of the tension regulator arm 6, so that the tension regulator arm 6 is connected to the first support shaft 3. Rotate clockwise around the center. Therefore, the tape guide pin 6a of the tension regulator arm 6 moves rightward in FIG. 1, so that the tape 5 is given the required back tension.

On the other hand, the tension regulator arm 6
As described above, when the regulator arm 6 and the rotating arm 4 rotate clockwise in FIG.
The rotating arm 4 rotates clockwise about the first support shaft 3 due to the tensile force of the spring 7 stretched between the two. Therefore, one end of the brake band 2 is pulled upward in FIG. Therefore, the brake band 2 comes into pressure contact with the outer peripheral surface of the supply side reel stand 1, and the required brake is applied to the reel stand 1.

Next, the operation of the tape feed control device when the tape runs at high speed will be described.

In this case, first the self-holding solenoid 16
The plunger 15 is operated to attract the pressure rod 18 against the elastic force of the compression spring 21 stretched between the solenoid 16 and the pressure rod 18.
is rotated clockwise in FIG. 1 about the second support shaft 17 (see FIG. 2). The above pressing rod 18
rotates, and the pressing part 18a at the other end is rotated by the rotating arm 4.
When one end is pressed, this rotating arm 4 rotates counterclockwise in FIG. 1 about the first support shaft 3, so that the brake band 2 loosens as shown in FIG. This brake band 2 is released from the supply side reel stand 1. Therefore, the tape 5 can be smoothly unwound from the supply reel to the take-up reel and rewound from the take-up reel to the supply reel at high speed and smoothly.

By the way, in the present invention, since the self-holding solenoid 16 is arranged in the mechanism for operating the band brake, even if the power is cut off while the tape 5 is running at high speed, the plunger of the self-holding solenoid 6 15 self-maintains in a suctioned state. Therefore, as shown in FIG. 2, in order to continue to press the rotating arm 4 in the counterclockwise direction in the figure, the brake band 2 is continued to be released from the supply side reel stand 1. Therefore, even if the take-up reel continues to rotate due to the action of inertia, high tension is not applied to the tape 5 or the tape 5 is not bent when the power is turned off.

In this embodiment, the system control circuit is configured to enter the eject mode when the power is turned on again after it has been once cut off.

As is clear from the above explanation, the present invention
In a tape feed control device that controls a reel stand that drives the inner supply reel of a pair of reels on which magnetic tape is wound, a rotatable tension arm having a tape guide planted at one end; A brake link that moves in response to this tension arm, a brake that brakes the supply side reel stand in response to the movement of this brake link, and a brake that moves the tension arm to a predetermined position when the magnetic tape normally runs. a control plate that moves the brake link so as to allow the brake to be applied, and a self-retainer that moves the brake link in a direction to release the brake of the link stand when the magnetic tape performs fast forward/rewind running. The self-holding solenoid maintains the brake release state of the reel stand even if the power is cut off while the magnetic tape is running in fast forward/rewind mode. Even if the power is cut off during running, the brake means can be self-maintained in a state in which it is released from the supply reel stand, so it is possible to prevent abnormally high tension or bending of the tape when the power is cut off. This is something that can be prevented.

[Brief explanation of the drawing]

Each of the drawings shows an embodiment of the present invention.
This figure is a schematic plan view showing the operating state of the tape feed control device when the tape is being fed at a constant speed, and FIG. 2 is a schematic plan view showing the operating state of the tape feeding control device when the tape is being fed at high speed. 1... Supply side reel stand, 2... Brake band, 5... Magnetic tape, 6... Tension regulator arm, 15... Plunger, 16...
...Self-holding solenoid.

Claims (1)

[Claim for Utility Model Registration] In a tape feed control device that controls a reel stand that drives the supply side reel of a pair of reels wound with magnetic tape, a tape guide is installed at one end. a freely rotatable tension arm; a brake link that moves in response to the tension arm; a brake that brakes the reel stand on the supply side in response to the movement of the brake link; a control plate that moves the brake link so that the tension arm can be moved to a predetermined position and the brake can be applied; and a control plate that allows the brake link to be applied to the link stand when the magnetic tape is fast forwarding or rewinding. The magnetic tape has a self-holding solenoid that moves in a direction to release the brake, and even if the power is cut off while the magnetic tape is running in fast forward/rewind mode, the self-holding solenoid maintains the brake release state of the reel stand. Tape feed control device.