JPH0317851A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To obtain a mechanism which has a simple constitution and has stability in travelling a magnetic tape by making the difference between the load torque of the brake at the time of normally rotating a take-up reel base and at the time of reversely rotating the take-up reel base. CONSTITUTION:At the time of intermittently feeding the tape by normal rotation, a sub-brake 45 abuts on the take-up reel base 9 in an escape direction (theta1>(31-32 deg.)), so that a control force set by a spring 46 is obtained and the take-up torque of the reel base 9 which rotates clockwise is reduced. On the other hand, at the time of intermittently feeding the tape by reverse rotation, the line connecting between the rotary supporting shaft of a slow brake 43 and a brake shoe 43a makes nearly a right angle with a line connecting between the brake shoe 43a and the center of the reel base 9, so that the load by the brake 43 is the same as in a normal rotating direction. But, the brake 45 abuts on the reel base 9 in a bite direction (theta2<16 deg.), so that the reflected reaction is added to the reel base 9 as the control force by the arm part 45b of the brake 45.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is a magnetic recording and reproducing device that performs intermittent playback in the forward and reverse rotation directions of a magnetic tape, in which the braking force is applied to the reel stand that winds the magnetic tape. This article relates to a magnetic recording/reproducing device that has a mechanism for providing both forward and reverse rotation. [Prior Art] In addition to normal playback and high-speed fast forward/rewind (hereinafter referred to as FF/REV) of magnetic tape, conventional magnetic recording and reproducing devices also perform so-called slow motion playback in which the movement of the reproduced image is slower than normal playback. Functions have been incorporated. This slow-motion playback is performed by splicing still images by displaying a still image on the screen and, after a certain period of time, feeding the magnetic tape to display the next still image, with the magnetic tape being moved intermittently.

When the magnetic tape runs and stops continuously, the imbalance in the tension distribution of the magnetic tape becomes more pronounced than during normal playback, and the running of the magnetic tape tends to become unstable. Depending on the conditions, the magnetic tape may rise or fall, causing damage to the tape on the guide pins in the set or inside the cassette. As a condition for preventing scratches, during intermittent playback, if the magnetic tape is wound with a low winding torque, the tape tension will be lowered and fs will be less likely to accumulate. However, in the past, the winding torque for intermittent playback and the winding torque for normal playback were often set to be the same, and if the winding torque for normal playback was lowered for intermittent playback, the magnetic tape could not be wound depending on the conditions. It is impossible to lower it below a certain value. In order to provide this winding torque difference, the following three types of configurations can be considered.

First, there is a method in which the active reel table is moved by a dedicated reel motor. If a dedicated motor is used, it is easy to set the winding torque for each mode, and the best torque value for intermittent playback can be selected. However, using a motor results in a significant increase in cost.

Next, in the system in which the reel stand is rotated by a capstan motor, it is designed to switch between two stages: strong torque for FF/REW and weak torque for playback and high-speed playback (Cue/Review). In order to add torque for intermittent feeding to this and make it possible to select three types, the mechanism becomes complicated, and the number of parts increases significantly, which also results in a significant increase in cost.

Next, there is a method in which braking force is applied to the take-up reel stand only during the intermittent feeding period. With this method, there is little cost increase and it is possible to reliably provide a difference between the winding torque for normal regeneration and the winding torque for intermittent feeding. However, conventionally,
The brake that applies braking force to the take-up reel stand is configured to apply the same load torque when the take-up reel stand rotates forward (normal playback direction, ie, clockwise) and reversely (reverse playback, ie, counterclockwise).

However, experiments have shown that when interleaved playback is performed in both the forward and reverse directions, a configuration in which the load torque applied to the take-up reel stand is different between forward and reverse rotations is advantageous for the running of the magnetic tape. Obtained.

The take-up reel winds the magnetic tape in the forward rotation direction, but in the reverse direction, it feeds out the magnetic tape and applies pack tension to the magnetic tape.

As mentioned above, in order to lower the winding torque during normal intermittent feeding compared to normal regeneration, the brake is brought into contact with the take-up reel stand during the intermittent feeding period. The load is the pack tension torque during intermittent reverse feed. However, experiments have shown that if the pack tension torque for intermittent reverse rotation is the same as the load torque for intermittent forward rotation, the magnetic tape will not run stably, causing the magnetic tape to rise or fall. It was found that in order to stabilize the system, it was necessary to increase the load in the reverse direction and create a difference in the load torque in the forward and reverse directions.

The method of applying different brake loads to the take-up reel stand during forward and reverse intermittent feed regeneration is to set mechanical modes for forward intermittent feed and reverse intermittent feed, and apply separate dedicated brakes to each. Alternatively, the second brake may be brought into contact only on the high load torque side.

Note that related devices of this type include, for example, Japanese Patent Application Laid-Open No. 64-84463. [Problems to be Solved by the Invention] The above-mentioned conventional technology can cope with the technical aspect of obtaining running stability in both forward and reverse directions for intermittent playback of magnetic tape, but it is possible to solve the problem by simplifying the mechanism and reducing manufacturing costs. No consideration was given to this, and there was a problem in that the mechanism was complicated, such as separate brakes coming into contact with the take-up reel stand for intermittent forward rotation and intermittent reverse rotation, resulting in increased costs.

An object of the present invention is to simplify the mechanism, to bring the same brake into contact with the take-up reel stand during forward rotation intermittent feed and reverse intermittent feed, and to make the load torque of the brake different between forward rotation and reverse rotation of the take-up reel stand. The purpose is to have

[Means for solving the problem] In order to achieve the above purpose, one brake is arranged that contacts the take-up reel stand during intermittent feed regeneration, and in the forward rotation direction, the brake touches the take-up reel stand in the escape direction. The brake rotates according to the mechanical mode, comes into contact with the take-up reel stand in the intermittent feed mode of the magnetic tape, and is biased by a spring suspended from the brake.

During normal intermittent feeding, the take-up reel table rotates in the same direction as normal playback, that is, clockwise. The brake that comes into contact with the take-up reel stand is designed to come into contact with the take-up reel stand, which rotates in the normal direction, in the direction of escape, and applies the load due to the aforementioned spring load to the take-up reel stand. .

During reverse intermittent feeding, the take-up reel stand rotates counterclockwise. The brake is configured to contact in the direction of biting,
The load due to brake deflection is added to the spring load.

This allows you to change the amount of load applied to the brake in the forward and reverse directions of the take-up reel table. [Example] This will be explained below.

FIG. 4 is an overall structural diagram of a magnetic recording/reproducing apparatus (VTR) according to the present invention in a recording or reproducing state. The magnetic tape 1 is pulled out from a cassette 17 mounted on the chassis 10, attached to a cylinder 19, and recorded or reproduced. This magnetic tape 1 is provided at the axis of a capstan drive motor 2, supported by a capstan 2a and a vinyl roller 3 that rotate integrally with the capstan, and is moved in the direction of arrow A by the constant rotation of the capstan rotation motor 2. Transferred at a constant speed.

In addition, a pulley portion 5a is connected via a belt 4 hung on a pulley 2b coaxially provided to the capstan drive motor 2.
The rotation is transmitted to the driving side gear 22 of the sliding clutch mechanism 21 via the gear 20 that meshes with the gear portion 5b (FIG. 5) formed integrally with the pulley portion. A friction member 24 is provided between the driving side gear 22 and the driven side member 23.
The rotation is transmitted to the driven member 23 by the frictional force generated by the pressure of the spring 25. Then, the rotation is transmitted to the take-up reel stand 9 via a gear 26 and an oscillating gear 27 provided on the upper part of the driven side member 23.
The magnetic tape 1 transferred at a constant speed is wound onto the reel 28 in the cassette 17 via the take-up reel stand 9.

FIG. 6 is an elemental plan view showing the link mechanism in the intermittent feeding mode of the magnetic tape.

During slow playback, the capstan 2a intermittently activates the magnetic tape 1, and the playback screen moves at a fraction of the normal speed.

The capstan motor 2 needs to have a certain degree of inertia during playback, but during intermittent playback such as slow motion or frame-by-frame playback, this inertia acts in the opposite direction, causing delays in the stop position and noise on the playback screen. To avoid this problem, brake the capstan motor 2 with the brake arm 41.
I am trying to secure a stopping position. This brake arm 41 is attached to a hole (not shown) arranged on the mechanical chassis 10 via the T-brake 39 and the operating arm 38. Rotation is transmitted to the mode gear 37 from the load motor 50 via a worm 51 and a gear 52.

During intermittent feeding, the brake arm 4l is released from the engagement of the T-brake 39, and the brake shoe 4lb is biased against the capstan motor 2 by a spring 42 whose end is suspended on the chassis 10, and the braking force is applied to the capstan motor 2. give. FIG. 7 shows a mode other than intermittent feed, for example, a playback mode. The mode gear 37 rotates and the groove 37a of the mode gear 37
The operating arm 38 that is engaged moves in the direction of the arrow, and the engaged T-brake 39 engages the cam 41a of the brake arm 41 to prevent the brake arm 4l from being pressed against the capstan motor 2.

Next, a slow brake 43 and a sub brake 4 that engage the brake arm 41 to apply braking to the take-up reel stand 9
5 will be explained using FIGS. 1 to 3.

FIG. 1 is an elemental plan view showing the winding mechanism during forward intermittent feeding. The slow brake 43 is mounted on the chassis 10, and in the intermittent feed mode, the slow brake 43 is mounted on the chassis 10.
4, the surface of the brake shoe 43a comes into contact with the take-up reel stand 9, and applies braking force to the take-up reel stand 9. As described above, the rotational torque transmitted from the capstan motor 2 and passed through the bellows clutch mechanism 21 is applied to the take-up reel stand 9. Since the slow brake 43 applies braking force to the take-up reel stand 9, the winding torque of the magnetic tape l on the take-up reel stand 9 is reduced by the braking force.

Further, a sub-brake 45 comes into contact with the take-up reel stand 9. A sub-brake 45 is also attached to the chassis 10, and is urged against the take-up reel stand 9 by a spring 46 whose one end is engaged with the chassis 0, and a brake shoe 458 is attached to the contact surface. sub brake 45
It has part 45b.

During forward intermittent feeding shown in FIG. 1, the sub-brake 45 abuts against the take-up reel stand 9 in the relief direction, so a braking force is applied by the spring 46, causing the take-up reel stand 9 to rotate in the direction of the arrow. reduce the winding torque.

Figure 2 shows intermittent reverse feed. Since the line connecting the rotational shaft of the slow brake 43 and the brake shoe 43a and the line connecting the brake shoe 43a and the center of the take-up reel stand 9 are approximately at right angles, the load applied by the slow brake 43 is the same as in the normal rotation direction. . However, since the sub-brake 45 contacts the take-up reel stand 9 in the biting direction, the reaction force caused by the bending of the arm portion 45b of the sub-brake 45 is applied to the take-up reel stand 9 as a braking force.

The method of setting the relief and bite angles is well known, and the explanation thereof will be omitted. Further, the braking force can be freely selected depending on the shape of the spring 46 and the arm portion. In reverse intermittent feed,
This braking force is used as a pack tension to feed out the magnetic tape 1.

FIG. 3 shows a mode other than intermittent feed, for example, a playback mode. As described above, the brake arm 41 rotates counterclockwise and separates from the capstan motor 2. The tip portion 41c of the rotated brake arm 41 is connected to the slow brake 43.
The slow brake 43 is pushed and rotated clockwise to separate from the take-up reel stand 9. Furthermore, the tip portion 43b of the slow brake 43 engages with the cam surface 45c of the sub-brake 45 during rotation, thereby biasing the sub-brake 45 counterclockwise. Therefore, the sub-brake 45 is separated from the take-up reel stand 9.

[Effects of the Invention] According to the present invention, the braking force applied to the take-up reel table can be varied between forward and reverse rotations in the same mechanical mode, resulting in a mechanism for stable magnetic tape running with a simple configuration. be able to. Also, since the same parts are used for forward and reverse rotation,
Cost reduction can be achieved by reducing the number of parts.

[Brief explanation of drawings]

The first construction drawing is a plan view of elements of a magnetic recording/reproducing device according to an embodiment of the present invention during forward rotation intermittent feeding, FIG. 2 is an elemental plan view of the same embodiment during reverse intermittent feeding, and FIG. 3 is the same embodiment. Fig. 4 is an elemental plan view showing the recording/reproducing state of the VTR @ structure; Fig. 5 is a side sectional view of the main part of power transmission to the magnetic tape winding device; Fig. 6. 7 is a plan view of the link mechanism of the magnetic tape winding device during intermittent feeding, and FIG. 7 is a plan view of the link mechanism during playback. 9... Take-up reel 41... Brake arm 43... Slow brake 45... Sub brake 1st [2N jNG3 Fig. A Fig. 6 Fig. 2 4 5... Sub brake Fig. 7 Fig. 4 Figure 5 Procedural amendment (voluntary) Name of the invention III related to 11 people who make corrections for magnetic recording 1λ reproduction

Claims (1)

[Claims] Magnetic recording using a cassette in which a pair of reels wound with magnetic tape are placed on the left and right, the magnetic tape is pulled out and attached to a rotating cylinder containing a built-in magnetic head, and the magnetic tape is continued by a capstan. In the playback device, the take-up reel stand that winds the magnetic tape during normal playback has a braking mechanism configured to apply a braking force by bringing a braking member into contact with the magnetic tape at least during an intermittent playback period of the magnetic tape; A magnetic recording/reproducing apparatus, wherein the braking force produces a load that differs depending on the direction of rotation of the take-up reel stand.