JP2568516B2 - Magnetic tape device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-motor drive type magnetic tape device, and more particularly to a system in which a magnetic tape is pulled out of a cassette and run in contact with a tape guide drum having a built-in rotary magnetic head. The present invention relates to a magnetic tape device of a type that can be applied to a video tape recorder (hereinafter abbreviated as VTR) or the like to significantly reduce damage to a magnetic tape.

2. Description of the Related Art Recent VTRs have come to have a function of reproducing a video image by moving a magnetic tape at a constant speed in both forward and reverse directions. The distance from the capstan to the reel on the take-up side is relatively short when the magnetic tape is fed in the forward direction, and there are few problems. The winding torque is set so that the magnetic tape and the rotating head are in contact with each other even at the maximum tape roll diameter on the winding side, in anticipation of tension loss at the rotating head and the tape running guide fixed post interposed between them. Then, when the tape roll diameter on the winding side is small, there is a problem that the tape tension becomes too large when the drawn-out magnetic tape is stored in the cassette, and the tape is damaged. The present invention provides a magnetic tape device that solves such a conventional problem.

Hereinafter, the above-described conventional magnetic tape device will be described with reference to the drawings.

FIG. 4 is a plan view of a main part showing a tape running state of the VTR. In the figure, a capstan shaft 10 and a pinch roller 12
The magnetic tape 14 sandwiched by the capstan shaft 10
Is rotated at a constant speed in the direction of arrow A by the counterclockwise rotation of. As is well known, the magnetic tape 14 is wound around the outer circumference of a tape guide drum 16 having a built-in rotary magnetic head for recording or reproducing a video signal, and its traveling is guided. The capstan shaft 10 is the capstan shaft 10
Forward / reverse capstan motor that shares the same axis with the rotating shaft
Rotated by 18 The capstan motor 18
The capstan shaft 10 is provided with an output gear 20 that rotates integrally with the capstan shaft 10.

The rotation of the output gear 20 is transmitted through idler gears 21 and 24 to a drive gear 22 disposed at substantially the same distance from the supply reel table 36 and the take-up reel table 34. The drive gear 22
A large gear 28a and a small gear 28b, which rotate integrally, are rotatably held at the tip of a rotating arm 26 which is rotatably supported coaxially with the large gear 28a. twenty two
I'm engaged. The rotating arm 26 is rotated in the same direction as the rotation direction of the drive gear 22 by friction means using a felt or the like, as is well known, and the small gear 28b is driven by the take-up reel base drive unit 30 or the supply reel base drive unit 32. Is driven to rotate.

As can be seen from FIG. 5, the supply reel base drive unit 32 rotates coaxially with the upper gear 32a and the upper gear 32a meshing with a gear portion formed on the outer periphery of the supply reel base 36, and The lower gear 32b meshes with a small gear 28b, and the rotation of the lower gear 32b is transmitted to the upper gear 32a by friction transmission means using a felt 32c and a spring 32d, which are well-known means. is there. The take-up reel base drive unit 30 has substantially the same configuration. Capstan axis
The rotation directions of the drive gear 22 and the drive gear 22 are opposite to each other. For example, when the capstan shaft 10 rotates counterclockwise in FIG. Is rotated clockwise, and as shown in FIG. 4, the rotating arm 26 is rotated and displaced in the direction of the supply reel base 36, and the small gear 28b is moved to the supply reel base drive unit 3.
2 and meshes with the lower gear 32b, rotates the supply reel base 36 in a counterclockwise direction, and transfers the magnetic tape 14 to the supply reel hub 40.
To take up.

Further, in a mode in which the capstan shaft 10 rotates clockwise to feed the magnetic tape 14 toward the take-up reel table 34, for example, in the reproduction mode, the capstan motor 18 is reversed to rotate the capstan shaft 10 clockwise. The drive gear 22 rotates counterclockwise when it is rotated in the
Is rotated in the direction of the take-up reel base 34, the small gear 28b meshes with the lower gear 30b of the take-up reel base drive unit 30, and the take-up reel base 34 is rotated clockwise to feed the magnetic tape. The 14 is wound on a take-up reel hub 38.

As a condition for winding the magnetic tape 14 sent out by the capstan shaft 10 on the take-up reel hub 38 or the supply reel hub 40 with a predetermined torque, the capstan shaft 10
, The diameter of the take-up reel hub 38 or the supply reel hub 40 is D, and the number of revolutions when driven by the capstan motor 19 is N.
The reduction ratio is set so that D · N> π · dn, and the difference in the number of rotations between the capstan shaft 10 and the driven-side reel base is determined by the take-up reel base drive unit 30 or the supply reel. Since the magnetic tape 14 is absorbed by the sliding of the friction means of the table drive unit 32, the magnetic tape 14 is wound around the driven reel table with a predetermined torque without slack.

When the tape pull-out posts 60, 61, 62, and 63 return to the positions in the cassette in the above-described configuration, when the capstan motor 18 rotates counterclockwise in the state of FIG. Magnetic tape rotates counterclockwise
14 can be stored in the cassette without slack.

Problems to be Solved by the Invention However, in the above configuration, the magnetic tape is wound up with a strong winding torque even when the tape is stored, so that the tape tension is particularly strong, and the tape pull-out posts 60, 61,
When the rollers 62 and 63 move from the position shown in FIG. 4 to a position in the cassette, tape damage occurs because the guide height of the magnetic tape 14 is not always parallel to the cassette.

The present invention has been made in view of the above problems, and when storing a drawn-out magnetic tape in a cassette, the reel base is rotated with a torque lower than usual so as to lower the tape tension and prevent the occurrence of tape damage immaturely. A magnetic tape device is provided.

Means for Solving the Problems In order to solve the above problems, the magnetic tape device of the present invention uses a motor rotatable in both forward and reverse directions, and a magnetic tape drive that is rotationally driven by the motor, and that includes a pinch roller. A tape running means including a capstan shaft capable of feeding the tape at a constant speed; a pair of tape reels for winding a magnetic tape; A pair of reel stands, rotation transmitting means for transmitting the rotation of the motor to a reel stand on the side of the pair of reel stands on which the capstan shaft sends out the magnetic tape with a predetermined torque; Tape withdrawing means for reciprocating between a first position and a second position for withdrawing the magnetic tape from the cassette and abutting the magnetic tape on the magnetic head; From first
Detecting means for detecting the movement of the reel base when the tape withdrawing means moves from the second position to the first position than when the tape withdrawing means is at the second position; The apparatus is provided with a torque varying means for varying the winding torque according to the detection signal of the detecting means so that the magnetic tape winding torque becomes small.

According to the present invention, when the magnetic tape pull-out means is returned to the position in the cassette by the above configuration, the tape winding torque of the reel base is reduced, so that the pulled-out magnetic tape is stored in the cassette. The tape tension is reduced, and the occurrence of tape damage can be largely prevented.

Hereinafter, one embodiment of the magnetic tape device of the present invention,
This will be described with reference to the drawings.

FIG. 1 is a plan view of a main part showing a tape running state of a VTR. In the figure, a capstan shaft 10 and a pinch roller 12
The magnetic tape 14 sandwiched by the capstan shaft 10
Is rotated at a constant speed in the direction of arrow A by the counterclockwise rotation of. As is well known, the magnetic tape 14 is wound around the outer periphery of a tape guide drum 16 having a built-in rotary magnetic head for recording or reproducing a video signal, and is guided to travel. The capstan shaft 10 is the capstan shaft 10
Forward / reverse capstan motor that shares the same axis with the rotating shaft
Rotated by 18 The capstan motor 18
The capstan shaft 10 is provided with an output gear 20 that rotates integrally with the capstan shaft 10.

The rotation of the output gear 20 is transmitted through idler gears 21 and 24 to a drive gear 22 disposed at substantially the same distance from the supply reel table 36 and the take-up reel table 34. The drive gear 22
A large gear 28a and a small gear 28b, which rotate integrally, are rotatably held at the tip of a rotating arm 26 which is rotatably supported coaxially with the large gear 28a. twenty two
I'm engaged. The rotating arm 26 is rotated in the same direction as the rotation direction of the drive gear 22 by friction means using a felt or the like, as is well known, and the small gear 28b is driven by the take-up reel base drive unit 30 or the supply reel base drive unit 32. Is driven to rotate.

As shown in FIG. 3, the supply reel base drive unit 32 rotates coaxially with the upper gear 32a and the upper gear 32a meshing with a gear formed on the outer periphery of the supply reel base 36, and The lower gear 32b is configured by a small gear 28b and a meshing lower gear 32b. is there.

The take-up reel base drive unit 30 has substantially the same configuration.

The rotation directions of the capstan shaft 10 and the drive gear 22 are opposite to each other. For example, in FIG.
Rotates counterclockwise to feed the magnetic tape 14 to the supply reel base 36.
The drive gear 22 rotates in the clockwise direction, and the rotating arm 26 is rotated and displaced in the direction of the supply reel base 36 as shown in FIG. 32, and the supply reel base 36 is rotated in a counterclockwise direction.
Is wound around the supply reel hub 40.

Further, in a mode in which the capstan shaft 10 rotates clockwise to feed the magnetic tape 14 in the direction of the take-up reel table 34, for example, in a reproduction mode, the capstan motor 18 is reversed to move the capstan shaft 10 When rotated clockwise, the driving gear 22 rotates counterclockwise, the rotating arm 26 is rotated and displaced in the direction of the take-up reel table 34, and the small gear 28 is rotated.
b is engaged with the lower gear 30b of the take-up reel base drive unit 30, the take-up reel base 34 is rotated clockwise, and the fed magnetic tape 14 is taken up by the take-up reel hub 38.

As a condition for winding the magnetic tape 14 sent out by the capstan shaft 10 on the take-up reel hub 38 or the supply reel hub 40 with a predetermined torque, the capstan shaft 10
, The diameter of the take-up reel hub 38 or the supply reel hub 40 is D, and the number of revolutions when driven by the capstan motor 19 is N.
The deceleration light is set so that D · N> π · dn, and the difference in the number of rotations between the capstan shaft 10 and the driven reel base is determined by the take-up reel base drive unit 30 or the supply reel described above. Since the magnetic tape 14 is absorbed by the sliding of the friction means of the table drive unit 32, the magnetic tape 14 is wound around the driven reel table with a predetermined torque without slack.

The above-described supply reel base drive unit 32 further includes a third
As clearly shown in the figure, a spring retainer 32e is fixed to an end of the boss 32f of the upper gear 32a. As shown in FIGS. 1 and 2, a felt 52 fixed to one end of a lever 50 rotatably supported on a substrate is formed on the outer peripheral surface of the spring retainer 32e so as to form a contact relationship. A tension spring 54 and a solenoid 56 are connected to the other end of the lever 50, and the felt 52 does not normally contact the outer peripheral surface of the spring retainer 32e due to the tension force of the tension spring 54 as shown in FIG. Although it is in the position, when the solenoid 56 is energized, the plunger 56a is sucked, so that the lever 50 rotates clockwise, and the felt 52 comes into contact with the outer peripheral surface of the spring retainer 32e as shown in FIG.
Now, the upper gear 32 through the felt 32c from the lower gear 32b.
Assuming that the torque transmitted to a is Ta and the brake torque due to the pressing of the felt 52 is Tb, the torque Ts transmitted from the upper gear 32a to the supply reel base 36 has the following relationship: Ts = Ta−Tb.

Tape drawer post 60,61,62,6 by switch 64
3 is detected to return to the position in the cassette as shown in FIG. 2, and when a voltage is applied to the solenoid 56, the magnetic tape winding torque of the supply reel base 36 is reduced as described above. The magnetic tape tension near the reel base 36 can be reduced. This means that in the running state shown in FIG. 1, the distance from the capstan shaft 10 to the supply reel table 36 is long, and tension loss occurs at the tape guide drum 16 and various posts interposed therebetween. Even when the tape roll diameter on the supply reel base 36 is the largest, the tape tension is large when the tape is stored when the transmission torque of the supply reel base drive unit 32 is large so that the magnetic tape 14 and the rotating head are in sufficient contact. This is extremely important because tape damage can occur too much.

In the above embodiment, the tape pull-out post 6 was used.
0, 61, 62, 63 are moved synchronously, so the switch 64 detects when the tape pull-out post 60, 61, 62, 63 has returned, turns on the solenoid 56, and takes up the supply reel base. Although the torque was reduced, the tape pull-out posts 60, 61,
The same effect can be obtained even when the voltage applied to the capstan motor 18 is reduced at the time of the return of the rollers 62 and 63 so that the winding torque of the supply reel base is smaller than the transmission torque of the supply reel base drive unit 32.

Advantageous Effects of the Invention As described above, according to the present invention, a motor capable of rotating in both forward and reverse directions, and a capstan driven by the motor and capable of feeding a magnetic tape at a constant speed with a pinch roller A tape running means including a shaft; a pair of tape reels for winding a magnetic tape;
A pair of reel bases respectively engaged with a pair of tape reels and integrally rotated, and the rotation of the motor is controlled to a predetermined one of the pair of reel bases on the side where the capstan shaft sends out the magnetic tape. Rotation transmitting means for transmitting with a torque of the tape; tape drawing means for reciprocating between a first position in the cassette and a second position for drawing the magnetic tape from the cassette and abutting on the magnetic head; Detecting means for detecting that the pulling means moves from the second position to the first position; and detecting that the tape pulling means moves from the second position to the first position than when the tape pulling means is at the second position. Torque varying means for varying the winding torque according to the detection signal of the detecting means so that the magnetic tape winding torque of the reel base is smaller when moving. Ri, pulled out the magnetic tape can be re-reduced tape tension when accommodated in the cassette, is intended to provide a great effect to prevent the occurrence of tape damage.

[Brief description of the drawings]

FIG. 1 is a plan view of a main part showing a magnetic tape reverse feed state in one embodiment of the present invention, FIG. 2 is a plan view of a main part showing a magnetic tape storage state in the embodiment of the present invention, and FIG. FIG. 4 is a cross-sectional view of a main part of a conventional magnetic tape device, showing a state in which a magnetic tape is reversely fed, and FIG. 5 is a cross-sectional view of a main part of a conventional magnetic tape device. 10 ... Capstan shaft, 12 ... Pinch roller, 14 ... Magnetic tape, 18 ... Capstan motor, 20 ... Output gear, 21 ... Idler gear, 22 ... Driving gear, 24 ... Idler gear, 26 ... Rotating arm, 28a ... Gear wheel, 28b
…… Small gear, 30… Take-up reel base drive unit, 32 ……
Supply reel base drive unit, 34 ... Take-up reel base, 36 ...
... Supply reel base, 38 ... Take-up reel hub, 40 ... Supply reel hub, 50 ... Lever, 56 ... Solenoid, 60,61,6
2,63 ... Tape drawer post, 64 ... Switch.

Claims (1)

(57) [Claims] A motor rotatable in both forward and reverse directions, and a tape running means including a capstan shaft rotatably driven by the motor and capable of feeding a magnetic tape at a constant speed with a pinch roller; A pair of tape reels for winding a magnetic tape, a pair of reel stands respectively engaged with the pair of tape reels and integrally rotating, and rotating the motor by the pair of reel stands. A rotation transmitting means for transmitting the magnetic tape to the reel base on the side where the capstan shaft sends out the magnetic tape with a predetermined torque; and a first position for pulling out the magnetic tape from the first position in the cassette and the cassette and attaching the magnetic tape to the magnetic head. A tape withdrawing means for reciprocating between two positions; a detecting means for detecting that the tape withdrawing means moves from the second position to the first position; The detecting means so that the magnetic tape winding torque of the reel base is smaller when the tape is pulled out and the tape withdrawing means moves from the second position to the first position than when the tape withdrawing means is at the second position. And a torque varying means for varying the winding torque in accordance with the detection signal.