JPS58150157A - Magnetic tape device - Google Patents

Abstract

PURPOSE:To accurately rotate the revolving member with a simple constitution and to accommodate the magnetic tape device of this invention itself to the multifunctioning, by constituting the device in such a way that prescribed rotations of the revolving body in accordance with each kind of operating condition are performed by means of the abutment of the cam surface of the revolving body to the revolving body and the cam surface is separated from the revolving body in the reproducing condition. CONSTITUTION:The end face 51 of a tension arm 45 abuts to the 1st-3rd cam surfaces of a sub-cam 142 arranged to the back of a base plate 2 through a hole 55 installed into the base plate 2 in accordance with the operating condition of this device. A band fastener 57a is placed on the tension arm 45 under a rotation-free condition and a band 59 is stretched between the band fastener 57a and another band fastener 57b fixed to the base plate 2 after the band 59 is put around a feed reel base 12. While it is in a stopping mode as shown by the diagram when the rotating angle of the sub-cam 142 is 0 deg., a post 47 is positioned at the opening section of a cassette 20, because the end face 51 of the tension arm 45 contacts with the 1st cam surface and controls the anticlockwise rotation of the tension arm 45.

Description

DETAILED DESCRIPTION OF THE INVENTION In the present invention, a magnetic tape is pulled out from a cassette having a built-in pair of glue hubs capable of winding a magnetic tape, and is placed on the outer periphery of a rotating magnetic head drum installed outside the cassette. The present invention relates to a magnetic tape device, such as a video tape recorder, which records or reproduces signals by running the tape at an angle.

In general, a magnetic tape device such as a cassette-type video tape recorder pulls out a magnetic tape from a cassette and runs it while adhering to the outer periphery of a rotating magnetic head drum at a predetermined angle, and keeps the tension of the magnetic tape almost constant while running. is equipped with tension control means. In many magnetic tape devices, when the magnetic tape is housed in a cassette, it is located near an opening provided in the cassette, and during recording/playback mode when the magnetic tape is pulled out.

Using a rotating member that rotates to an operating position where it can contact the running magnetic tape and then rotates according to the tension of the magnetic tape, the amount of displacement of the rotating member is applied to the braking force of the reel stand. The structure is such that the tension is controlled to a constant level in response to changes in the tension. In such a configuration, the required rotation angle from the position of the rotating member at the opening of the cassette to the operating position is generally quite large, and even a slight stroke of the drive member that rotates the rotating member can cause the rotational angle to change. In order to enable a fixed amount of rotation, a large lever ratio relative to the center of rotation is required, and therefore high precision is required for each component.
Some types of magnetic tape devices are configured to rotate the rotary member to compensate for the insufficient stroke of the drive member by using the movement of a tape pull-out member for pulling the magnetic tape out of the cassette. Furthermore, recent video tape recorders tend to be multi-functional, and especially when performing reverse playback or high-speed reverse playback with the magnetic tape pulled out from the cassette, the magnetic tape that runs attached to the rotating member is to prevent tension loss.

releasing the attachment of the magnetic tape to the rotating member;
It was necessary to reduce the attachment angle, and the rotating member had to be rotated. This could be achieved by using a plunger, but it would be heavier, make more noise, and consume more power.

In view of the above points, the present invention provides a magnetic tape device that allows the rotary member to be rotated with high precision with a simple structure without using a plunger, and is also capable of responding to multifunctionalization.

Hereinafter, the present invention will be explained in detail based on illustrated embodiments.

FIGS. 1, 3, and 4 show top views of the present embodiment in various states. In the figure, a shaft 4.
The take-up reel stand 10 and the supply reel stand 12, which are each rotatably fitted loosely into
4. They are engaged with the supply reel hub 16 and can be rotated together by claws 8 provided on both the reel bases 10 and 12.

FIG. 2 shows a sectional view of the reel stand drive system, in which the take-up reel stand 10 and the supply reel stand 12 each have a 9-wheel gear 30.
40, the reel gear 30.40 meshes with a take-up 1 reel idler gear unit 62 and a supply reel idler gear unit 62, which are rotatably loosely fitted to a shaft 50.60 implanted on the substrate 2, Rotationally driven. The take-up reel idler gear unit 62 and the supply reel idler gear unit 62, as shown in FIG. The structure is such that the signal is transmitted to the take-up reel idler gear 54b meshing with the reel gear 30, 40 and the supply reel idler gear eab via the clutch means used.

On the other hand, a capstan 72 that is pivotally supported by a bearing member 7o fixed to the substrate 2 has a rotating roller portion 74 in a part thereof,
A predetermined pressing force is applied to the rotating roller portion 74, and the rotation is transmitted to the main idler 76, which is pressed against the rotating roller portion 74. The main idler 76 has a belt 84 stretched between a pulley portion 78 that is integrally constructed and a relay roller 82 that is rotatably loosely fitted to a shaft 8o that is implanted in the base plate 2. 82. A rotating arm 88 having a rotatable idler gear 86 supported at one end is loosely fitted to the shaft 80, and a multi-pole magnetized magnet 90 is attached to the outer periphery.
is placed integrally with the shaft 80 so that it is substantially the same as the shaft 80. Furthermore, a magnetic material 92 having a magnetic hysteresis characteristic is fixed to the inner periphery of the relay roller 82 so as to face the magnet 90 with a predetermined clearance. A rotational force is generated in the same direction as the rotational direction of the relay roller 82 and is applied to the rotating arm 88 . Further, the idler gear 86 is configured to constantly mesh with a gear portion 94 provided on the relay row 5'82, and the take-up reel idler gear 54 is rotated by the rotation of the relay roller 82 depending on the operation mode of the device.
a or the supply reel idler gear 64a to selectively transmit the rotation of the capstan 72 to the take-up reel stand 10 or the supply reel stand 12 depending on the direction of rotation. Shaft 18 embedded in substrate 2
A pinch roller lever 22 is rotatably fitted into the shaft 24, and a shaft 24 is embedded in one end of the pinch roller lever 22.
A pinch roller 192 is rotatably supported.

A crimp lever 32 having an elongated length 28 is loosely fitted onto a shaft 26 implanted in the substrate 2 so as to be rotatable and slidable in the longitudinal direction, and a pin 34 implanted at one end of the crimp lever 32 is freely rotatable. The connecting arm 36 is loosely fitted, and the other end of the connecting arm 36 is rotatably fitted to the pin 3B implanted at the other end of the pinch roller lever 22. Also, the crimp lever 3
A tension spring 44 is stretched between the shaft 26 and the spring hook 42, and the crimp lever 32 is attached upward in FIG. The end of the elongated hole 2β is in contact with the shaft 26. That is, the pinch roller lever 22, the connecting arm 36, and the pressure lever 32 constitute a so-called toggle mechanism. Further, at the other end of the crimp lever 32, a bottle 46 is attached to the substrate 2.
It extends toward the rear surface of the device through a hole (not shown) provided in the main rod 48, and is configured to abut against a bent portion 21 provided in a main rod 48, which will be described later. Therefore, when the main rod 4B, which will be described later in FIG. The pinch row 2192 rotates until it comes into contact with the capstan 72. The pinch roller lever 22 is not rotated after that, but the crimp lever 32 continues to rotate clockwise, and the crimp lever 32 is guided into the elongated hole 28 against the biasing force of the tension spring 44, as shown in FIG. τ moves downward, and at the same time, the pinch roller 192 presses the capstan 72 with a predetermined pressure.
It will be crimped.

In the reproduction mode, as shown in Fig. 3, the supply reel hub 16
The magnetic tape 180 wound above is recorded/reproduced by guiding tape pull-out members 182 and 183 having guide posts 23, 26 and 27, 29 installed from the front of the cassette 20 through guide grooves 31 and 33, respectively. fixed head 188 and tape guide 190 fixed to the substrate 2
Attach to. Furthermore, since the capstan 72 is rotating clockwise in FIG. 3, the main eye 76 is rotating counterclockwise in FIG. 3, and the belt 84 and relay roller 82 are also rotating counterclockwise in FIG. Rotate. Therefore, the rotating arm 88 is given a rotational force in the counterclockwise direction in FIG. 3 about the shaft 80, and the idler gear 86, which is rotating clockwise in FIG. 3, meshes with the winding sole eye 2 gear 64a, so that the winding The take-up reel stand 1o rotates clockwise via the clutch means described above, and the pinch roller 192 and the capstan 72 work together to wind the magnetic tape 180 fed at a constant speed around the take-up hub 14 without slack. To go.

On the other hand, a driving gear 160 driven by a motor (not shown) is disposed on the back surface of the substrate 2 shown in FIG. The sub cam 142 is loosely fitted into the sub cam 142. Further, the sub-cam 142 is rotatably loosely fitted onto a shaft 164 embedded in the base plate 2, and has a gear on its outer periphery having the same number of teeth as the outer peripheral gear of the sub-cam 142, so that it rotates in synchronization with the same angle as the sub-cam 142. The main cam 162 is a positive cam having a groove 16b extending over 360 degrees as shown in FIG. 10, and its lift curve changes the amount of lift as shown in FIG. A cam follower 166, which will be described later, moves only in this section. Furthermore, the rotation shaft 4 of the take-up reel stand 1o extending from the front surface to the back surface of the board 2 and the take-up reel idler gear unit 6
2 rotation shaft 6o and a guide shaft 13 implanted on the back surface of the substrate 2.
2 and a rotation shaft 164 of the main cam 162 has a cam follower 166 that engages with a groove 166 of the main cam 162.
The main rod 48 has guide grooves 35 , 37 , 39 provided therein.

It is loosely fitted so that it can freely move back and forth along 41. Further, the main rod 48 is provided with the bent portion 21 so as to come into contact with a pin 46 provided at the other end of the crimp lever 32.

Further, the sub cam 142 is also 36 in diameter as shown in FIG.
The cam is a positive cam having a groove 144 extending over 0°, and its lift curve is as shown in FIG.
6 and partially indicated by a dashed line
0 is designed to reciprocate like the main rod 48.

Further, the shaft 43 implanted on the surface of the substrate 2 has a.

A tension arm 45 with a boss 47 implanted at one end is rotatably fitted loosely, and the tension arm 4
6 is biased to rotate counterclockwise in FIG. 1 by a tension spring 49. Depending on the operation mode of the device, the end surface 51 of the tension arm 46 is arranged on the first cam surface 63a and the second cam surface 63b of the sub-cam 142 disposed on the back surface of the substrate 2.
, third cam surface 63C (not shown in FIGS. 1 to 6).

This is illustrated in FIGS. 6 to 9. ) and are in contact with each other through a hole 56 provided in the substrate 2. Further, the tension arm 46 has a first band fastener 57a rotatably mounted thereon, and the tension arm 46 has a first band fastener 57a mounted on the tension arm 46, and winds the knot 69 around the supply reel stand 12 between the first band fastener 57a and the second band fastener s7b fixed to the base plate 2. They are perfectly connected. 1 and 6 when the rotation angle of the sub cam 142 is O0 shown in FIG. 10.
At this time, the end surface 61 of the tension arm 46 is in contact with the first cam surface 53a and restricts the rotation of the tension arm 46 in the counterclockwise direction. cassette) 20.

Thereafter, the sub cam 142 moves clockwise in FIG.
It begins to rotate in the positive direction of the rotation angle shown in Figure 0.

Tension arm 46 in contact with first cam surface ε3a
maintains the state shown in FIG. On the other hand, although a detailed explanation will be omitted, the tape pull-out members 182 and 183 are adapted to move in accordance with the rotation of the main cam 162.
As shown in FIG. 10, from the stopped state of the main cam 162, the clockwise 111 rotation angle in FIG. 6 is from 400 to 1800.
The tape pull-out member 182,1
83, the tape pull-out members 182 and 183 move from the position shown in FIG. 1, the tension arm 46 rotates counterclockwise in FIG. After the tension arm 46 is no longer in contact with the other, the tension arm 46 begins to rotate counterclockwise from the position shown in FIG. The end surface 61 of is separated from the first cam surface 53a, and begins to come into contact with the second cam surface s3b11. Furthermore Zabucam 1
42 rotates from 1 to 1 and reaches a rotation angle of 190° as shown in FIG.

Since the band 69 wound around the supply reel stand 12 is stretched without slack, the tension arm 46 is restricted from rotating counterclockwise thereafter.
The end surface 61 of 5 is also spaced apart from the cam surface 53a. FIG. 7 shows a state in which the sub-cam 142 has subsequently rotated to a rotation angle of 206°, and the end surface 61 is completely separated from any of the cam surfaces 53m, 53b, and 53c, resulting in a regenerated state. At this time, as is well known, the braking force applied to the supply reel stand 12 by the band 69 is changed depending on the balance between the tension spring 49 and the tension of the magnetic tape 180 attached to the bottle 47, and the tension of the magnetic tape 180 is increased. It will be controlled at a certain level.

Also, as is well known, when the supply reel stand 12 is rotated counterclockwise in the state shown in FIG.
The band brake formed by the band 69 and the band 69 requires a large rotational force because it is in the biting direction.

Therefore, when winding the magnetic tape 180 on the supply reel stand 12, for example in a high-speed reverse play mode, the tension arm 46 is rotated clockwise as shown in FIG. 3, and the band 59 is loosened as shown in FIG. Therefore, it is necessary to prevent the brake force from being applied to the supply reel stand 12. In this embodiment, the Zap cam 142 is further rotated to a rotation angle of 26o0, the third cam surface 53c and the end surface 51 are brought into contact as shown in FIG. 8, and the tension arm 45 is rotated clockwise in FIG. Then, hold the rice at a position where the attachment between the post 47 and the magnetic tape 180 is almost released, and then remove the magnetic tape 18.
The wrapping angle with respect to the tape guide 190 of 0 is reduced.

Next, the operation of the embodiment of the present invention will be explained. When the playback button (not shown) is pressed from the stop state shown in FIGS. 1 and 4, the drive is driven by the motor (not shown). Gear 160 begins to rotate clockwise in FIG. 6, causing sub cam 142 and main cam 162 to rotate counterclockwise and clockwise, respectively, in FIG. When the main cam 162 rotates to a rotation angle of 4o0, the tape pulling member 182
, 183 start moving and begin to pull out the magnetic tape 180 from the cassette) 20, and at the same time the main rod 4
8 begins to move rightward in FIG. 6 following #j1166, and the pinch roller lever 22 begins to rotate.

On the other hand, when the sub-cam 142 rotates through a rotation angle of 160°, the tension arm 46 switches its end face 61 from the first cam surface 53a to the second cam surface sab, so it is rotated significantly counterclockwise in FIG. but still the second cam surface s3
Since the post 47 is in contact with the magnetic tape 180, the post 47 does not come into contact with the magnetic tape 180 in an impactful manner, despite the rotation biasing force of the tension spring 49 in the counterclockwise direction in FIG. Subsequently, when the cam 162 rotates at a rotation angle of 180''j, the movement of the tape pull-out members 182 and 183 is completed, resulting in the state shown in FIG. 3. At this time, as shown in FIG. 10, the main rod 4
8 has moved about 4 degrees to the right in FIG. When the sub cam 142 further rotates and reaches a rotation angle of 19o0, the end surface 51 of the tension arm 45 is moved to the second cam surface 63.
b, and the post 47 rotates to a position where it can completely come into contact with the magnetic tape 180. Furthermore cam 1
62 continues to rotate up to a rotation angle of 205°, the main rod 48 moves to the right in FIG. The motor stops and the sub cam 142. The rotation of the main cam 162 also stops.

At this time, the capstan 72 is rotated clockwise in FIG. 3, and the main idler 76 is rotated counterclockwise in FIG. Therefore, the belt 84. The relay roller 829 rotating arm 88 also rotates counterclockwise in FIG. 3, and the idler gear 86 rotating clockwise in FIG. The take-up reel stand 10 rotates clockwise in FIG. 3, and the pinch roller 192 and capster 772 work together to wind the magnetic tape 180 fed at a constant speed around the take-up reel hub 14 without slack. As the magnetic tape 180 is fed out, the tension arm 46 rotates to a predetermined position as described above, resulting in a reproduction mode in which the tension of the magnetic tape 180 fed out from the supply reel hub 14 is controlled at a constant level.

Next, when a highway regeneration button (not shown) is pressed from this state, the sub cam 142 and main cam 162 are further rotated by the motor up to 260° as shown in FIG. At this time, the main rod 48 does not move, so the pinch roller 192 remains pressed against the capstan 72 with a predetermined pressing force, and the tension arm 45
Since it comes into contact with the cam surface 53c, it rotates to the position shown in FIG. 4. At this time, the capstan 72 rotates counterclockwise at high speed in FIG. The supply reel hub 14 engaged with the supply reel 12 is wound around the supply reel hub 14 . Since the attachment of the magnetic tape 180 to the post 47 of the tension arm 46 is substantially released, and the winding angle of the magnetic tape 180 with respect to the tape guide 190 is small, the friction loss of the magnetic tape 180 during running is small and stable. Tape running is often obtained. Further, although a detailed explanation will be omitted, the position where the sub cam 142 has further rotated to a rotation angle of 300° is in a recording temporary stop mode, and the end surface 61 of the tension arm 46 comes into contact with the third cam surface 53c and tension is applied. The shape of the third cam surface 53c is determined so that the arm 46 is rotated clockwise in FIG. 8 to completely separate the post 47 and the magnetic tape 180.

Next time you press the stop button, the main and evening rotations will be reversed and the sub cam 1
42. The main cams 162 begin to rotate clockwise and counterclockwise in FIG. 6, respectively, and after passing through positions corresponding to the reproduction mode, the tension arm 46 pulls the end surface 51 by the second cam SSa and the first cam surface sab. Spring 4
It is rotated significantly clockwise in FIG. 3 against the biasing force 9.

Thereafter, the tape pull-out members 182 and 183 are moved toward the cassette 20, and the pinch roller 19 is moved toward the cassette 20.
2 is spaced apart from the capstan 72. Further, the capstan 72 rotates in the long direction in FIG. 3, the idler gear 86 meshes with the supply reel idler gear 64a, and the supply reel stand 12 rotates counterclockwise in FIG.
The magnetic tape that has been pulled out is wound around a supply reel hub 16 without slack. And subcam 142. The main cam 162 continues to rotate, and when the rotation angle reaches 0°, a switch (not shown) is operated to stop the motor, and the rotation of the capstan 72 is also stopped, resulting in the stopped state shown in FIG.

As described above in detail based on the embodiments of the present invention, the present invention rotates the braking force to the supply reel stand by contacting the magnetic tape and rotating and displacing it according to the tension of the magnetic tape. A cam of the rotating body is provided with a rotatable rotating body equipped with a control means that increases or decreases the tension according to the amount of displacement to keep the tension constant, and controls a predetermined rotation of the rotating body according to various operating modes of the device. This is achieved by the contact between the surface and the rotating body, and in the reproduction mode, the rotating body and the cam surface are separated from each other, and the rotating body is linked with the operation switching means, so that the operation is controlled. It is possible to accurately move the rotating body depending on the situation and to ensure synchronization with other members, which greatly contributes to stable running of the magnetic tape. Also,
It is possible to perform rotational displacement independently of the movement of the operation switching means linked to the rotating body, allowing more operations to be performed by the rotation of the 9 rotating bodies, and since both sides of the rotating body can be used, the device can be made smaller. This has a great effect on reducing costs and reducing costs. Furthermore, the shape of the cam surface not only makes it possible to make a large rotation of the rotating body at a small rotation angle, or to make a minute rotation at a relatively large rotation angle, but also allows the required speed of the movement to be reduced. Even if the rotational speed of the rotating body is constant, it can be changed as necessary, so even when complex operating modes change due to multi-functionality, the running of the magnetic tape can be easily and stably controlled with an extremely simple configuration. It has many great effects.

[Brief explanation of the drawing]

FIG. 1 is a surface view of the main parts of an embodiment of the present invention in a stopped mode;
Fig. 2 is a schematic sectional view of the reel drive system, Fig. 3 is a front view of the main parts in the reproducing mode, Fig. 4 is a front view of the main parts in the high-speed reverse reproducing mode, and Fig. 6 is the back side of the main parts in the stopped mode. figure,
6, 7, and 8 are explanatory diagrams of the operation of the tension lever, FIG. 9 is a schematic sectional view of the tension lever operating system, and FIG. 10 is a cam lift curve diagram. 14... Take-up reel no. 16...
Supply reel huff, 2o...cassette, 46...
...Tension arm, 47...Post,
48... Main rod, 51... End face, 53a... First cam surface, 63b...
Second cam surface, 53C...Third cam surface, 69...
...Band, 13o...Sub rod, 14
2...Sub cam, 162...Main cam, 18o...Magnetic tape. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 6
Figure 53c

Claims (1)

[Claims] Using a cassette that includes a pair of reel knobs capable of winding a magnetic tape and has an opening that allows the magnetic tape to be drawn out, the magnetic tape is pulled out from the cassette. It is configured to be pulled out and run along the outer periphery of a rotating magnetic head drum installed outside the cassette to record or reproduce signals, and is engaged with the pair of reel hubs and rotates integrally with the reel hubs. a supply reel stand and a take-up reel stand; a motor capable of forward and reverse rotation; a rotating body having a cam surface and rotationally driven by the motor; and a rotating body that moves to a plurality of positions following the rotating body. an operation switching means for switching the operation mode of the device into various modes corresponding to each position; and a magnetic tape located near the opening of the cassette in the stop mode and pulled out to the outside of the cassette in the signal reproduction mode. The supply reel table is rotated to a position where it can be contacted, and then rotated according to the tension of the magnetic tape, thereby increasing or decreasing the braking force on the supply reel base according to the amount of rotational displacement to maintain the tension constant. and a rotatable rotating body equipped with a control means to maintain the rotational speed, and a predetermined rotation of the rotating body according to the various operation modes is performed by abutment between a cam surface of the rotating body and the rotating body. The magnetic tape device is further characterized in that the rotating body and the cam surface are separated from each other in the reproduction mode.