JPH01205751A - Reverse traveling tape tension mechanism - Google Patents

Abstract

PURPOSE:To make tape tension constant regardless of the change of winding diameter by controlling breaking force applied to the reel disk of a take-up reel base in accordance with the fluctuation of the tape tension at the time of reverse traveling. CONSTITUTION:In the reverse traveling, when the tape winding diameter of the take-up reel base 7 is large, the tape tension between the base 7 and a capstan 18 is large and therefore, a guiding arm 24 turns counterclockwise. The displacement of the arm 24 is transmitted to a breaking arm 25 through a link 26 and the arm 25 turns counterclockwise against a spring 27. Thus, the breaking force of a block breaking member 25b to a reel disk 7a is released. As the winding diameter gets smaller, rotational load is decreased, the arm turns clockwise and the breaking force is increased. Consequently, the tension is made constant regardless of the winding diameter of the tape.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a reverse running tape tension mechanism, and more particularly to a reverse running tape tension mechanism that applies 1< tension to the tape during reverse running.

Conventional Technology For example, in a video tape recorder, magnetic recording/reproduction is performed by pulling out a tape from a tape cassette, winding it around a guide drum, and running the tape spirally around the outer periphery of the guide drum at a predetermined angle. ing. In this type of video tape recorder, a certain tension is applied to the tape at the entrance side of the guide drum so that the running tape stably adheres to the outer periphery of the guide drum as described above.

However, when the tape is unwound from the supply reel and runs along the guide drum, the tension is obtained by the action of the normal running tape tension mechanism, but when the tape runs in reverse, contrary to the above, the normal running tape tension mechanism is in a tension-released state and no tension can be applied to the guide drum outlet side, that is, to the tape that is fed out from the take-up reel and driven by the capstan. Therefore, in a video tape recorder, even in the reverse search mode where the tape wound on the take-up reel is played back while being rewound onto the supply reel, a brake force is applied to the take-up reel stand that drives the take-up reel, and the tape is taken up. A reverse running tape tension mechanism that applies tension to the tape from the reel to the capstan is provided separately from the normal running tape tension mechanism.

In this reverse running tape tension mechanism that applies pack tension to the tape running in reverse, for example, when the tape running direction is switched to reverse running, a lever having a block brake member is moved toward the take-up reel stand by the pressing force of a torsion spring. There is a configuration in which the take-up reel table is rotated to apply a braking force to the take-up reel stand.

Problems to be Solved by the Invention However, in the above mechanism, when the tape runs in reverse,
Since the brake member is always pressed against the outer periphery of the take-up reel stand with a constant spring force, the pack tension torque remains constant regardless of changes in the tape winding diameter. The tape tension fluctuates approximately 3.2 times during the change from the beginning of winding to the end of winding. That is, as the number of tape windings wound around the take-up reel decreases, the pack tension of the tape increases.

Therefore, for example, even in reverse search mode,
If the pack tension of the tape unwound from the take-up reel table fluctuates greatly in a short period of time, the tape running along the rotating drum will fluctuate in the tape running direction and in the upward and downward directions, making the reverse playback screen unstable. There is a problem that this happens.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a reverse running tape tension mechanism that solves the above problems.

Means and Function for Solving the Problems The present invention provides, in the above-mentioned reverse running tape tension mechanism, a displacement member that is displaceable in accordance with fluctuations in tape tension between the take-up reel stand and the capstan. The brake member is displaced in the direction of pressing the take-up reel stand or in the direction of releasing the suppression along with the displacement of the displacement member so as to keep the pressure constant, so that the tension of the tape fed out from the take-up reel does not change during reverse running. It is.

Embodiment FIGS. 1 to 3 show a first embodiment of a reverse running tape tension mechanism according to the present invention.

FIG. 1 shows the stop mode of the video tape recorder. In Figure 1, tape cassette (indicated by a dashed line in the figure)
1 accommodates a supply reel 3 and a take-up reel 4 on which tape 2 is wound, and is mounted at a predetermined mounting position above the chassis 5! Arrived at A. Further, reel shafts (not shown) of the supply reel stand 6 and the take-up reel stand 7 (not shown) are fitted into the reel hubs of the supply reel 3 and take-up reel 4.

Front tape bus 2 mounted on the front of tape cassette 1
A tape loading member 8.9 is relatively fitted inside a. When the playback mode is operated, the tape loading member 8.9 moves in the directions of arrows A and B along the guide 10° 11 formed on the chassis 5, and the tape 2 in the tape cassette 1 is pulled out. It will be done.

As shown in FIG. 2, when the tape loading member 8°9 reaches the loading position where it comes into contact with the stopper 12.13, the tape 2 is loaded onto the impedance roller 14, the full-width erasing head 15, the guide drum 16, the audio control head 17, and the cap. A tape path 2b is formed that comes into sliding contact with the stand 18 and the pinch roller 19. Further, in conjunction with the movement of the tape loading member 8 in the six directions of the arrow, the rotating arm 20 of the normal running tape tension mechanism rotates counterclockwise, and the tape 2 fed out from the supply reel 3 is Tension works.

Reference numeral 21 denotes a control plate (indicated by a broken line in the figure), which is provided on the lower surface side of the chassis 5 so as to be slidable in the directions of arrows C and D. The control plate 21 has a protruding pin 21a on the left end that engages with a cam groove (not shown) of the cam mechanism, and is displaced in accordance with the operation of the cam mechanism.

In the playback mode, the control plate 21 slides in the direction of arrow C and releases the pinch roller arm 22.

Therefore, the pinch roller arm 22 rotates counterclockwise, and the pinch roller 19 presses the tape 2 onto the capstan 18.

Reference numeral 23 denotes a reverse running tape tension mechanism which is an important part of the present invention, and as shown in FIGS.
4, a brake arm 25 that applies a braking force to the take-up reel stand 7, and a link 26 that connects the guide arm 24 and the brake arm 25. The guide arm 24 is rotatably supported on the chassis 5 by a shaft 24a, and a guide ball 24b stands vertically at the tip. The guide arm 24 also has a pin 24 connected to one end of the link 26.
It has G.

Further, the brake arm 25 is rotatably supported by a shaft 25a, and a block brake member 25b is integrally fixed to one end. Further, the other end of the brake arm 25 has a pin 2 that engages with a long hole 26a at the other end of the link 26.
5G stands vertically, and on the lower surface of the brake arm 25 is a contact pin 2 that slides into contact with the cam portion 21b of the control plate 21.
5d is provided.

27 is a coil spring that biases the brake arm 25 in a clockwise direction. A torsion spring 28 is wound around a pin 26b that protrudes from the side of the link 26. One end engages with the link 26, and the other end engages with the pin 25 of the brake arm 25.
Contact with G. In the stop mode, the torsion spring 28 presses and biases the guide arm 24 to the counterclockwise rotation limit position to hold the guide arm 24.

The brake arm 25 is rotated clockwise or counterclockwise as the displacement of the guide arm 24, which rotates in response to fluctuations in tape tension, is transmitted via the link 26. That is, as will be described later, the brake arm 25 is rotated due to the balance between the tape tension and the tensile force of the coil spring 27, and the brake force applied to the take-up reel stand 7 is reduced to zero so that the tape tension remains constant.

In addition, the "stop mode" shown in Fig. 1 and the "stop mode" shown in Fig. 2
When the brake arm 25 is in the regeneration mode, the contact pin 25d of the brake arm 25
Since the block brake member 25b of the brake arm 25 is in contact with the cam portion 21b of the control plate 21, the brake arm 25 is displaced to a position where the block brake member 25b is separated from the outer periphery of the reel disk 7a of the take-up reel stand 7.

Here, the operation during reverse running will be explained.

When the reverse search mode is operated in the above playback mode, the control plate 2
1 slides in the direction of arrow C from the reproduction mode position shown in FIG. Therefore, the contact pin 25 of the brake arm 25
d fits into the notch 21c of the control plate 21,
Rotate clockwise. As a result, the block brake member 25b comes into contact with the reel disc 7a of the take-up reel stand 7. Further, the guide arm 24 connected to the brake arm 25 via the link 26 rotates clockwise, and the ball 24b slightly pulls out the front tape bus 2a.

At this point, the tension of the tape 2 acts on the ball 24b of the guide arm 24, and the guide arm 24
It is rotated counterclockwise by the buttension. or,
The rotation arm 20 on the supply side is rotated in the direction away from the tape 2, and no braking force is applied to the supply roll table 6.

In this state, the supply reel 3 is rotated counterclockwise,
The tape 2 wound around the take-up wheel 4 runs in the direction of arrow E. That is, the tape 2 of the take-up rule 4 is attached to the guide arm 2.
The guide ball 24b1 passes through the capstan 18, the audio control head 17, and the tape loading member 9 on the winding side, and reaches the guide drum 16. Further, the tape 2 is played by running along the outer periphery of the guide drum 16 in a spiral manner, and thereafter passes through a tape loading member 8 on the supply side and a full-width erasing head 15, and is wound onto the supply reel 3.

When the tape 2 is run and rewound as described above, the pack tension of the tape 2 is kept constant by the operation of the reverse running tape tension mechanism 23. That is, when the tape winding diameter of the take-up reel stand 7 is large, the tape tension between the take-up reel stand 7 and the capstan 18 is sufficiently large, so that the guide arm 24 rotates counterclockwise. This displacement of the guide arm 24 is transmitted to the brake arm 25 via the link 26.
5 rotates counterclockwise against the tensile force of the spring 27.

Therefore, the block brake member 25b is displaced in a direction away from the reel disc 7a, and the braking force on the reel disc 7a is relaxed.

As the tape 2 is wound from the take-up reel stand 7 to the supply reel 3, the tape winding diameter of the take-up reel stand 7 becomes smaller. Along with this, the rotational load on the take-up reel stand 7 decreases, and the tape tension gradually decreases.

However, when the tape tension between the take-up reel stand 7 and the capstan 18 becomes less than a predetermined value, the guide arm 24 rotates in the timing direction until the tape tension and the spring force of the spring 27 are balanced. This displacement of the guide arm 24 is transmitted to the brake arm 25 via the link 26, and the brake arm 25 is rotated clockwise by the spring force of the coil spring 27, increasing the pressing force of the block brake 25b against the reel disc 7a.

In this way, even in the reverse search mode, as the tape winding diameter of the take-up reel stand 7 becomes smaller, the braking force applied to the reel disk 7a is automatically controlled so that the tape tensicon of the tape 2 reaching the capstan 18 remains constant. is maintained. Therefore, regardless of the tape winding diameter, the tape 2 can run along the guide drum 16 in a stable state due to the action of a constant back tension, and a good reverse reproduction image can always be obtained in the video tape recorder.

FIG. 5 shows a second embodiment of the present invention. In FIG. 5, the same components as those in FIG. 1 are denoted by the same reference numerals, and the explanation thereof will be omitted.

In FIG. 5, reference numeral 31 denotes a guide arm, which is rotatably supported on the chassis 5 by a shaft 31a.

This guide arm 31 has a substantially triangular shape, and has a pin 31C at its corner that slides against the guide ball 31b1, on which the tape 2 slides, and the cam portion 33a of the control plate 33. Further, the guide arm 31 is urged to rotate clockwise by the spring force of the coil spring 34. 35 is a band brake member, which is attached to the reel disc 7a of the take-up reel stand 7;
One end is screwed onto the chassis 5, and the other end is locked in the hole 31d of the guide arm 31.

Therefore, the reverse running tape tension mechanism 36 is composed of the guide arm 31, the coil spring 34, the band brake member 35, and the like.

In the stop mode and the playback mode, the guide arm 31 rotates counterclockwise against the tensile force of the spring 34, so that the band brake member 35 is loosened and separated from the reel disc 7a. However, in the reverse search mode, as the control plate 33 slides in the direction of arrow C, the bin 31C moves into the notch 33b1 of the cam portion 33a.
．． :11 people, and the guide arm 31 rotates clockwise as shown in FIG. As a result, the band brake 35 is in a state without slack and comes into sliding contact with the reel disc 7a.

Therefore, as the tape winding diameter of the take-up reel stand 7 becomes smaller and the tape tension becomes smaller, the guide arm 31 is rotated clockwise until the tensile force of the spring 34 and the tape tension are balanced. Therefore, the band brake 35 tightens the reel disk 7a more tightly as the guide arm 31 rotates clockwise.

That is, the braking force acting on the reel disc 7a is automatically controlled according to the variation in tape tension, and the increase or decrease in this braking force causes the tape 2 to reach the capstan 18.
The tension is held constant.

Note that the reel disc 7a is fixed by the band brake member 35.
When tightening the outer periphery of the reel disc 7a, even if the reel disc 7a rotates slightly eccentrically, the band brake 35 will tighten the reel disc 7a.
Since it is wound around half the circumference of reel disk 7a, braking force can be applied without being affected by rotational wobbling of reel disk 7a, and the tape pack tension can be kept constant during reverse running.

Effects of the Invention As described above, the reverse running tape tension mechanism of the present invention includes a brake that is applied to the reel disk of the take-up reel stand in response to fluctuations in tape tension when the tape on the take-up reel is run in reverse toward the supply reel. The force can be automatically controlled, and the tension of the tape from the take-up reel to the capstan can be kept constant, even in response to changes in tape tension due to changes in the tape winding diameter of the take-up reel. . Therefore, even in the reverse search mode, when the tape running in reverse passes through the capstan and attaches to the guide drum, the tape can run stably without fluctuating in the tape running direction or in the upward or downward direction. It has features such as the ability to obtain search playback images.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a video tape recorder to which a first embodiment of the reverse running tape tension mechanism of the present invention is applied, FIG. 2 is a plan view of the playback mode state, and FIG. 3 is a plan view of the reverse running tape tension mechanism. FIG. 4 is a side view, FIG. 4 is a plan view in a reverse mode state, and FIG. 5 is a plan view of a tape recorder to which a second embodiment of the present invention is applied. 2... Tape, 7... Take-up reel stand, 7a... Reel disk, 18... Capstan, 21... Control plate, 23... Reverse running tape tension mechanism, 24... Guide arm, 24b...
Guide ball, 25... Brake arm, 25b...
・Block brake member, 26...link, 27...
・Coil spring, 28...Torsion spring, 31...
Guide arm, 33... Control plate, 34
... Coil spring, 35 ... Band brake member, 3
6... Reverse running tape tension mechanism. Patent applicant: Victor Japan Co., Ltd.

Claims (2)

[Claims] (1) During reverse running, when the tape on the take-up reel is brought into sliding contact with the capstan and the rotating drum and rewound to the supply reel side, a brake member is pressed against the take-up reel stand that rotates with the take-up reel to create tension on the tape. In the reverse running tape tension mechanism, a displacement member is provided between the take-up reel stand and the capstan and is displaced according to fluctuations in tape tension, and the displacement of the displacement member is adjusted so as to keep the tension of the tape constant. A reverse running tape tension mechanism characterized in that the brake member is also displaced in a direction in which the take-up reel stand is pressed or in a direction in which the pressure is released. (2) When the tape on the take-up reel is brought into sliding contact with the capstan and the rotating drum and rewinded to the supply reel side during reverse running, a braking force is applied to the take-up reel stand that rotates together with the take-up reel, and the tape is In a reverse running tape tension mechanism that applies tension, a displacement member is provided between the take-up reel stand and the capstan and is displaced in accordance with fluctuations in tape tension, and the tape is tensioned in accordance with displacement of the displacement member. and a band brake member wrapped around the outer periphery of the take-up reel stand so as to keep the tension constant.