JPS5853726Y2 - Braking device for magnetic recording and reproducing equipment - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a braking device for a magnetic recording/reproducing device, and particularly includes a dedicated drive motor and a braking device for each of a supply reel and a take-up reel, as well as tape tension detection means. The present invention relates to a braking device for a magnetic recording/reproducing device.

In a magnetic recording/reproducing device, if dedicated drive motors are used to rotate the supply and take-up reels,
When winding a tape at high speed, it is extremely easy to do so, and the operation device can be configured purely electrically, but the followability of the drive system of the magnetic recording and reproducing device and the operability of the operation device are Due to the problems caused by this, various adverse effects occur.

These problems include, for example, when the tape is brought into the fast rewind state by pressing the fast rewind button on the fast rewind operation device from the tape fast rewind drive state, the take up reel drive motor is turned off. Even if it is stopped and its torque is zero, the opposite supply reel drive motor operates and provides a very large reverse torque, creating a large tension.

Furthermore, if you perform a stop operation during fast forwarding (including fast winding and fast rewinding), the tape will run at a fast speed, so
The mechanical braking effect becomes unstable.

For example, if the braking force on the supply side is too strong compared to the braking force on the winding side of the tape, the tape may be stretched or cut. If the braking force is too weak compared to the braking force on the supply side, the tape will loosen and be wound around the reel on the supply side, causing the tape to bend or break.

These drawbacks are that the diameter of the tape wound on the reel changes from time to time while the tape is running, and as a result,
This occurs because the moments of inertia of both reel systems are unbalanced.

In order to solve this problem by using a detection arm for tape tension control, for example, when operating the tape so that it runs in the opposite direction, the torque of the reel motor on the supply side is electrically controlled by the output of the detection arm. However, if the take-up reel motor has a large torque, the tape tension will be a large tension commensurate with that torque.

Furthermore, when a stop operation is performed during tape running, the tape tension control circuit is shut off, making it impossible to stabilize the tape tension.

The present invention aims to provide a braking device for a magnetic recording/reproducing device that eliminates the above-mentioned drawbacks, and can move the tape from its high-speed transport state without applying harmful tension to the tape and without causing the tape to loosen. , which can be run in the opposite direction or stopped.The feature is that when the tape is running in the reverse direction, it cuts off the drive signal to the winding motor, The reel drive motor on the side is controlled by a tape tension detection mechanism to keep the tape tension constant, and the tape speed is detected to automatically reverse the drive servo motor.

Hereinafter, details of an example of the present invention will be explained with reference to FIGS. 1 to 3.

FIG. 1 is a plan view of an example of the braking device of the present invention. and a band brake 1b applied to the band brake 1b.
One end is fixed to the fixed end 1C, and the other end is fixed to the midpoint 1e of the lever 1d.

One end 1f of this lever 1d is rotatable, and the other end 1g is pivotally connected to a plunger 1h for releasing the supply brake device.

The supply reel 1' is driven by a supply reel motor 3.

The braking device 2 of the take-up reel τ is constructed in the same way as the braking device 1 of the above-mentioned supply reel 1', so the corresponding suffix a '' h is added to the reference numeral 2 for similar parts. Although the detailed explanation thereof will be omitted,
The take-up reel 2' is driven by a take-up reel motor 4.

The tape 17 is transferred from the supply reel 1' to the take-up reel 1.
Roller 15a of supply side tension arm 15 → detection roller 7 → head group 8 → shifter 9 → between pinch roller 11 and capstan 10 → guide roller 12 → winding through roller 16a of tension arm 16 on winding side The tension arm 15 on the supply side and the tension arm 16 on the take-up side are provided with tape tension detectors 5 and 6, respectively.
are provided, and tape tension detection circuits 5a and 6a are provided respectively in connection therewith.

These detectors 5.6 are composed of, for example, differential transformers.

Furthermore, as shown in the perspective view of FIG. 2, a tape speed detection rotary plate 24 is fixed to the rotation shaft 7' of the detection roller 7.
It rotates together with this rotation shaft 7'.

A large number of tape speed detection holes 26 are bored at predetermined intervals along the circumferential direction of the rotary plate 24, and are opposed to each other with the tape speed detection holes 26 in between. element 21 is arranged.

The output of this light receiving element 21 is supplied to a tape speed detection circuit 28.

The outputs from the above-mentioned detection circuits 5a, 6a and 28 are respectively supplied to circuits configured as shown in the system diagram of FIG.

That is, the outputs of tape tension detection circuits 5a and 6a pass through amplification circuits 30 and 31, and then are sent to switching circuits 32 and 3.
3 respectively.

On the other hand, these switching circuits 32 and 33 are controlled by a control signal from a control circuit 36 to be described later, and the outputs of the amplification circuits 30 and 31 are transferred to drive amplification circuits 34 and 3.
5 to the supply reel motor 3 and take-up reel motor 4, respectively, while the output from the tape speed detection circuit 28 is provided to a control circuit 36.

This control circuit 36 is further provided with a group of operation buttons 37 of the magnetic recording/reproducing device, and therefore outputs a control signal in accordance with these buttons 37 and the tape speed detection circuit 28.

As described above, the output of the control circuit 36 is given as a control signal to the switching circuits 32 and 33, respectively, and is also applied to the plungers lh and 2h for the braking devices 1' and 2' of the supply and take-up reels, and the pinch roller 11. and shifter 9
The control signals are also given to plungers 38, 39 (not shown), etc. for moving the and.

The operation of the present invention configured as described above will be explained.

The supply and take-up reel motors 3 and 4, when energized, generate torques such as to rotate the reels 1' and 2', respectively, in the directions shown by arrows C and D in FIG.

Now, if the device is driven to the fast winding or fast rewinding state and the tape 17 is running in the direction of arrow A or B in FIG. R
EW is being pressed, the supply and take-up plungers 1h and 2h are controlled by a signal from the control circuit 36, and the band brakes lb and 2b are pressed against the drum 1a.
, 2a, respectively, the supply side and take-up side braking devices 1
, 2 have been released, respectively.

At this time, the tape tension detector 5 or 6 detects the movement of the tension arm 15 or 16, and its differential transformer converts the amount of change in the tension of the tape 17 into voltage, which is then used to drive the supply or take-up reel motor 3 or 4. control the torque of

In this case, for fast winding, the tape tension detector 6 on the winding side is inactive, and the reel motor 4 on the winding side generates a dog torque force to wind the tape 17.

In this state, the tape 17 moves at high speed in the direction of arrow A (first
Since the detection roller T is rotated by the tape 17, the tape speed detection rotating plate 24 having the through hole 26 also rotates.

Therefore, a signal with a frequency proportional to the tape speed is generated in the light receiving element 21, and this signal is supplied to the tape speed detection circuit 28, so that the detection circuit 28 generates a voltage proportional to the tape speed.

Now, from the fast forward F, FWD state as described above, press the operation button group 3.
When button REW 7 is pressed, supply and winding plungers Ih and 2h are activated by a control signal from the control circuit 36.
are opened, respectively, and the shoes of the brake bands 1b, 2b come into contact with the drums Ia, 2a, respectively.

At the same time, a control signal from the control circuit 36 is applied to the switching circuit 33 so that the take-up reel motor 4 is stopped, and the driving torque of the take-up reel motor 4 in the direction of the arrow is eliminated.

At this time, the reel motor 3 on the supply side is controlled by the output of the detection circuit 5a of the tension detector 5 that detects the movement of the tension arm 15 so that the tape tension is constant.

In this state, the speed of the tape 17 gradually decreases, and the running direction of the tape 17 finally comes to be reversed due to the torque force in the rotational direction C of the supply side reel motor 3.

Therefore, the tape speed detection circuit 28 described above detects the speed of the tape 17.
When it is detected that the speed of the reel has become almost zero, the braking devices 1 and 2 of both reels are released.

At the same time, the torque relationship between both reel motors 3 and 4 is also switched.

For this reason, up until now, torque control has been used to control tape tension.
Since the supply side reel motor 3 is switched to the take-up side reel motor 4, the torque of the supply side reel motor 3 becomes large torque (full torque), and the winding reel motor 3, which used to have a large torque, becomes a large torque (full torque). The torque of the take-side reel motor 4 is smaller than the torque of the supply reel motor 3.

Therefore, by the detection circuit 6a of the tape tension detector 6,
The tension of the take-up reel motor 4 is controlled so that the tension of the tape 17 is constant.

Since the present invention is constructed and operated as described above, the tape can be stopped and reversed extremely quickly from its high-speed state with a constant tape tension.
It has great practical effects when used as a braking device for magnetic recording and reproducing devices for broadcast stations or studios.

[Brief explanation of drawings]

FIG. 1 is a schematic plan view showing the magnetic recording/reproducing apparatus of the present invention, FIG. 2 is an enlarged perspective view of the detection roller portion of the present invention, and FIG. 3 is a system diagram of the present invention. In the figure, 1 and 2 are supply and take-up side braking devices, 3,
4 is a supply and take-up side reel motor, 5.6 is a supply and take-up side tape tension detector, 5a and 6a are supply and take-up side tape tension detection circuits, 7 is a detection roller, 2
8 is a tape speed detection circuit, 32 and 33 are switching circuits, and 36 is a control circuit.

Claims (1)

[Scope of utility model registration request] A magnetic recording/reproducing device comprising a dedicated drive motor associated with a supply reel and a take-up reel, a braking device, tape tension detection means provided in the running path, and tape speed detection means associated with the running of the tape. In the apparatus, when the tape is running, the braking device is released, the reel drive motor is controlled by the tape tension detection means to maintain a constant tape tension, and from that state the tape runs in the opposite direction to the above running direction. When this operation is performed, the braking devices of both reels are operated, the drive signal of the reel drive motor on the take-up side is cut off, and the reel drive motor on the supply side is further controlled by the output of the tape tension detection means to maintain a constant tension. In this state, the running speed of the tape is slowed down by the tape tension, and when the tape speed detecting means detects that the tape running speed has almost stopped, the braking devices of both the reels are released. A braking device for a magnetic recording and reproducing apparatus, further comprising switching the reel drive motor controlled by the tape tension detection means to another reel drive motor other than the reel drive motor.