JPH0567928U - Tape tension device - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] The tension and relaxation of the band brake can be reliably controlled without changing the tape running position during tape rewinding and fast-forwarding, and the drive shaft during assembly. Tape tension device that can optimally adjust the offset between the band brake and the band brake. [Structure] One end of a band brake 4 is attached to a back tension arm 5, and the other end is attached to a rotating plate 16 provided with an offset adjusting plate 20. The drive plate 17 is engaged with the cam portion 14b provided on the outer peripheral portion of the back tension arm driving cam gear 14 and the adjusting plate 20. At the time of mode switching from the recording / reproducing state to the rewinding or fast-forwarding state, the rotating plate 16 having the end portion of the band brake fixed is rotated by the cam portion 14b via the drive plate 17 and the adjusting plate 20. The back tension is released without moving the arm 5. By adjusting the mounting angle of the adjusting plate 20 with respect to the rotating plate 16, the cylindrical side surface portion 2a of the drive shaft 2 and the brake 4 can be adjusted.
You can adjust the offset between and.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a device for optimally controlling the tape tension of a recording / reproducing device using a magnetic tape such as a video tape recorder, a digital audio tape recorder, etc. With a simple structure, initial setting of the tension applied to the magnetic tape is easy. And a tape tension control device with good assembling workability.

[0002]

[Prior Art]

 Conventionally, this type of tape tension device is generally of a type that applies tension by interlocking with a back tension arm so that a band brake abuts so as to wind around the cylindrical side surface of the magnetic tape running drive shaft. . Details of this type of conventional tape tension device will be described with reference to FIGS.

6 and 7 are plan views of a conventional tape tension device, FIG. 6 shows a state in which a braking force is applied to a drive shaft, and FIG. 7 shows a state in which the braking force is released. Is shown. Referring to these drawings, in order to run the magnetic tape 8 wound on a reel (not shown) on the chassis 1, a reel shaft 3 planted on the chassis 1 is partially formed in a cylindrical shape. A drive shaft 2 having a side surface 2a is rotatably supported, and is configured so that it can be fitted to a reel by a drive portion 2b. A band brake 4 having one end fixed to the chassis 1 by a mounting screw 12 or the like is in contact with the cylindrical side surface 2a of the drive shaft 2 so as to wind around the cylindrical side surface 2a.

The other end of the band brake 4 is a back tension arm 5 whose one end is rotatably supported by a tension arm shaft 13 implanted in the chassis 1, and a guide provided on the back tension arm 5. It is attached to the pin 5a via a connecting arm 10 pivotally supported. Further, one end of a back tension spring 11 is attached to the back tension arm 5 for adjusting the tension of the band brake 4 contacting the drive shaft 2 by rotating the back tension arm 5.

The connecting pin 6 embedded in the back tension arm 5 is provided in a cam groove 14a formed integrally with a cam gear 14 rotatably supported by a cam shaft 9 embedded in the chassis 1. The cam gear 14 is engaged and is rotated by a predetermined angle in accordance with the rotation of the cam gear 14. The cam gear 14 is generally connected to a motor (not shown) for tape loading and mode switching via a gear train for rotation. Further, the back tension arm 5 is provided with a tension pole 7 which is in sliding contact with the magnetic tape 8 and detects the tension thereof.

In the back tension device configured as described above, the band brake 4 whose one end is fixed on the chassis 1 receives the force of the back tension spring 11 and the other end thereof rotates in the direction of arrow B to drive the drive shaft. The band breaker 4 which is in contact with the cylindrical side surface 2a of 2 strongly slides to brake the rotation of the drive portion 2b of the drive shaft 2 with a constant force. Further, when the magnetic tape 8 wound on a reel (not shown) fitted with the drive unit 2b is delivered by the rotation of the drive unit 2b, the magnetic tape 8 slides on the tension pole 7 provided on the back tension arm 5, It always runs at a constant speed. When the amount of the magnetic tape 8 wound on the reel changes, the load changes, or the running state of the magnetic tape 8 changes, the balance between the rotation of the drive unit 2b and the running speed of the magnetic tape 8 is lost. As a result, the back tension, which is the tension in the direction opposite to the running direction of the magnetic tape 8, changes.

At this time, if the tension in the running direction of the magnetic tape 8 becomes strong, the tension pole 7 is rotated in the direction of the arrow A by the tension of the magnetic tape 8 and is wound around the cylindrical side surface 2 a of the drive shaft 2. The brake 4 is loosened, the rotational speed of the drive shaft 2 is increased, and the magnetic tape 8 is delivered faster than before. When the tension in the running direction of the magnetic tape 8 becomes weaker, the tension pole 7 is rotated in the direction of arrow B by the force of the back tension spring 11 stretched on the back tension arm 5, and the cylinder of the drive shaft 2 is rotated. Since the band brake 4 wound around the side surface 2a is tightened, the rotation speed of the drive shaft 2 is decreased, the feeding speed of the magnetic tape 8 is decreased, and a constant back tension is always applied to the magnetic tape 8. Therefore, stable tape running can always be obtained.

Then, in order to run the magnetic tape 8 at a high speed during, for example, fast-forwarding or rewinding, it is necessary to release the back tension device in order to reduce the running resistance of the tape. That is, the cam gear 14 is always rotated during the rewinding, fast-forwarding, stop and eject modes, and the cam groove 14a formed in the cam gear 14 is rotated, so that the back tension arm 5 engaged with the cam gear 14 is mechanically moved by the arrow. It was necessary to loosen the band brake 4 by rotating it in the A direction and fixing the back tension arm 5 in a fixed position with the cam groove 14a.

However, when the back tension arm 5 is rotated in the direction of arrow A at this time, the tension pole 7 provided on the back tension arm 5 also moves largely, and the tension pole 7 separates from the magnetic tape 8. It will be. Therefore, the running path of the magnetic tape is greatly different between when the magnetic tape 8 is run in this relaxed state and when the back tension device is not removed. In addition, since the movement of the back tension post 7 at the time of mode switching becomes large, the magnetic tape 8 is likely to be greatly loosened or, conversely, is likely to be in a tensioned state with excessive tension. In addition, parts with high shape and dimensional accuracy of the band brake 4 are used, and special attention is paid when assembling those parts as well. If the mounting position accuracy is also not high, the offset between the drive shaft and the band brake 4 will be incorrect. As a result, the tension and relaxation control operations are not performed reliably, resulting in incomplete contact, and even braking force cannot be generated. There was a problem that caused the.

[0010]

[Problems to be solved by the device]

As described above, in the conventional tape tension device, it is necessary to move the back tension arm to release the back tension device at the time of fast-forwarding and rewinding. The driving route of the car will be very different. In addition, the movement of the back tension post at the time of mode switching becomes large, so the tape is slackened, and conversely, it tends to be in a state of being stretched with excessive tension. In addition, the parts with high shape and dimensional accuracy of the band brake are used, and special attention is paid to the assembly of these parts. If the mounting position accuracy is not high, the offset between the drive shaft and the band brake will be incorrect. As a result, the tension and relaxation control actions are not performed reliably, resulting in incomplete contact, and even braking force cannot be generated. There was a problem of causing. Therefore, the present invention is intended to solve the above problems, and it is possible to reliably control tension and relaxation of the band brake without changing the tape traveling path, and to assemble the assembly. It is an object of the present invention to provide a tape tension device that can adjust the offset between the drive shaft and the band brake at the optimum time and surely.

[0011]

[Means for Solving the Problems]

 The tape tension device of the present invention comprises a back tension arm rotatably provided on a base member and a first tensioning arm for urging the back tension arm in a direction in which the back tension arm is pressed against a tape running by rotation of a drive shaft. Biasing means, a band brake whose one end is attached to the back tension arm so that it is pressed against the drive shaft when the back tension arm rotates in the tape pressing direction, and recording / reproducing, rewinding, fast forward, stop, and eject of tape. And a cam member having a first cam portion that engages with the back tension arm, and a first rotary member that is rotatably provided on the base member and has the other end of the band brake attached. A moving member and a second rotating member having the same center of rotation as that of the first rotating member and configured so that the relative angle to the first rotating member can be adjusted and fixed. Member, a second urging means for urging the first rotating member in the direction in which the band brake is pressed against the drive shaft, and a first rotatably provided on the base member and formed on the cam member. A second cam portion and a third rotating member engaged with the second rotating member, wherein the first cam portion has a cam member from a recording / reproducing position to a rewinding or fast-forwarding position. It is formed so as to keep the back tension arm in the tape pressing position when rotated, and separate the back tension arm from the tape when the cam member is rotated to the eject position. , When the cam member is rotated from the recording / reproducing position to the rewinding or fast-forwarding position, the first rotating member is rotated in the band brake relaxing direction via the third and second rotating members. Characterized by being formed

[0012]

[Action]

 In the tape tension device having the above structure, the first cam portion keeps the back tension arm at the tape pressing position when the cam member is rewound from the recording / reproducing position, fast-forwarded, or rotated to the stop position, and , The back tension arm is formed so as to separate from the tape when the cam member is rotated to the eject position, and the second cam portion is such that the cam member is rewound from the recording / reproducing position or fast-forwarding position. Is formed so as to rotate the second rotating member and the first rotating member integrally fastened with the second rotating member through the third rotating member in the band brake relaxing direction. Since the back tension arm is held at the tape pressing position during recording and playback, the tension of the band break is controlled by rotating and displacing according to the tension of the magnetic tape. That. As a result, the braking force applied from the band brake to the drive shaft is controlled and the back tension applied to the magnetic tape is kept constant. On the other hand, when the recording / playback state is switched to the tape rewinding or fast-forwarding state, the back tension arm is held at the tape pressing position, but the band brake is loosened by the rotation of the first rotating member, so that the drive is performed. The braking force applied to the shaft is released. Therefore, the tape can be rewound or fast-forwarded at high speed. In addition, since the traveling path of the magnetic tape does not change significantly by switching between the recording / playback state and the tape rewinding or fast-forwarding state, a large slack is generated in the magnetic tape or, conversely, tension is applied with excessive tension. Or the rigidity of the band brakes causes the band brakes to try to extend straight, so the band brakes will not be completely separated from the drive shaft, causing variable load and uneven rotation. There is no such problem. Further, when the relative angle of the first rotating member with respect to the second rotating member is changed, the first cam rotated by the second cam portion via the third and second rotating members. Since the rotational position of the moving member changes, the pressure contact strength between the drive shaft and the band brake changes. Therefore, by adjusting the relative angle of the first rotating member with respect to the second rotating member, the offset between the drive shaft and the band brake can be adjusted optimally or reliably. Since such an adjusting mechanism is provided, the workability of assembling when initially setting the pressure contact amount of the band brake with respect to the drive shaft is very good. Since the back tension arm is separated from the magnetic tape during ejection, the back tension arm does not get in the way when taking out the cassette containing the magnetic tape.

[0013]

【Example】

 1, 2 and 3 are plan views showing an embodiment of the tape tension device of the present invention. FIG. 1 is a state when tension is applied to the drive shaft, and FIG. 2 is a state in which the tension is released. The state, FIG. 3 is a state explanatory view showing an intermediate process leading to the eject. Further, FIG. 4 is an exploded view of a main part, and FIG. 5 is a perspective view of a jig used for operating the offset adjusting mechanism of the present invention. The same components as those in the conventional configuration shown in FIGS. 6 and 7 are designated by the same reference numerals.

Referring to these figures, in order to run the magnetic tape 8 wound on a reel (not shown) on the chassis 1, a part of the reel shaft 3 planted on the chassis 1 has a cylindrical shape. A drive shaft 2 having a formed side surface 2a is rotatably supported, and is configured so that it can be fitted to the reel by a drive portion 2b. A tension pole 7 is erected on one end of the surface of a back tension arm 5 rotatably supported by a tension arm shaft 13 planted in the chassis 1, and is provided between the tension pole 7 and a fulcrum. One end of a band brake 4 which is abutted so as to wind around the cylindrical side surface 2a of the drive shaft 2 is fixed to a connecting arm 10 rotatably attached to the guide pin 5a. On the other end side, one end of a back tension spring 11 as a first biasing means for adjusting the tension applied to the band brake 4 by rotating the back tension arm 5 in the direction of arrow B is attached. . Further, the connecting pin 6 planted in the back tension arm 5 is a cam groove as a first cam portion formed in a cam gear 14 rotatably supported by a cam shaft 9 planted on the chassis 1. 14a, the back tension arm 5 is configured to rotate by a predetermined angle as the cam gear 14 rotates.

The other end of the band brake 4 is fixed to a rotating plate 16 as a first rotating member that is rotatably supported by a rotating plate shaft 15 that is erected on the chassis 1. The hand brake 4 is arranged so as to be in sliding contact with the substantially semicircle of the cylindrical side surface portion 2a of the drive shaft 2. The rotating plate 16 is formed with a spur gear 16b centered on a mounting hole 16a for the rotating plate shaft 15, and a slot 16c for inserting the adjusting screw 21 is formed in the lower portion thereof. Further, an offset adjusting plate 20 as a second rotating member is rotatably supported by the rotating plate shaft 15. The offset adjusting plate 20 has a substantially triangular shape, and has a round hole 20a for attaching to the rotating plate shaft 15 at one end and a round hole 20b for guiding the offset adjustment at the other end, and the other end. An elongated hole 20c is formed at the end. The long hole 20c is inserted into and guided by the drive plate shaft 18 provided upright on the chassis 1. Further, 20d is a screw hole for the adjusting screw 21.

Next, a rotating plate spring 19 that applies a biasing force to the bending portion 20f of the offset adjusting plate 20 in the direction in which the band brake 4 is pressed against the cylindrical side surface portion 2a of the drive shaft 2, that is, in the arrow C direction. One end of is attached. Further, a drive plate shaft 18 erected on the chassis 1 is rotatably supported by a drive plate 17 as a third rotating member, and a connecting portion 17a provided on the drive plate 17 is attached to an offset adjusting plate 20. It is configured to come into contact with the provided bent portion 20e and to transmit rotation only in one direction. Immediately when the drive plate 17 rotates in the direction of arrow C about the drive plate shaft 18, the offset adjustment plate 20 rotates in the direction of arrow D about the rotary plate shaft 15. The rotating plate 16 fastened integrally with this also rotates in the direction of arrow D. As described above, the rotary plate 16 and the drive plate 17 can be interlocked.

In such a configuration, when the pressure contact amount of the band brake 4 with respect to the cylindrical side surface portion 2a of the drive shaft 2 is initialized, it is adjusted as follows. The jig 22 shown in FIG. 5 is used for this adjustment. The jig 22 is a round bar 22b having a handle 22a at its base end, and a gear 22c fixed to the portion near the tip. To make the above adjustments, first loosen the adjusting screw 21 using a screwdriver. Then, the tip end of the round bar 22b of the jig 22 is inserted into the guide round hole 20b of the offset adjusting plate 20, and the gear 22c is meshed with the spur gear 16b of the rotating plate 16. Next, the handle 22a of the jig 22 is operated to rotate the gear 22c, thereby rotating the rotating plate 16 in the direction of arrow C or D using the rotating plate shaft 15 as a guide. By doing so, the other end of the band brake 4 is tensioned or loosened, and the amount of pressure contact of the band brake 4 with respect to the cylindrical side surface portion 2a of the drive shaft 2 changes. Then, the rotating plate 16 is stopped at that position in a state where the pressure contact amount of the band break 4 is appropriately set, and in this state, the adjusting screw 21 is tightened to fix the rotating plate 16 to the offset adjusting plate 20. . In this way, the pressure contact amount of the band break 4 with respect to the cylindrical side surface portion 2a of the drive shaft 2 is adjusted.

In this embodiment, the mounting position of the other end of the band brake 4 with respect to the rotating plate 16 is the axis of the drive shaft 2 and the axis of the rotating shaft 15, which is the center of rotation of the rotating plate 16. Since it is set in the vicinity of the connecting straight line, when the rotating plate 16 rotates in the direction of the arrow D, the other end (fixed end) of the band brake 4 is the cylindrical side surface portion 2 a of the drive shaft 2. It moves almost tangentially to. Therefore, the band brake 4 can be separated from the drive shaft 2 substantially evenly with a small movement of the rotary plate 16, and the rigidity of the band brake 4 causes the band brake 4 to extend straight. These devices can be compactly arranged around the drive shaft 2 without the problem that the 4 remains completely separated. Further, the drive plate 17 has an engaging portion 17b provided thereon in contact with an outer peripheral cam portion 14b as a second cam portion provided on the outer peripheral portion of the cam gear 14, so that the drive plate 17 is rotated by a predetermined angle by the rotation of the cam gear 14. Is configured.

The cam gear 14 is connected to a motor (not shown) for tape loading and mode switching via a gear train so as to be rotated, so that rotation transmission is also reliable and the cam gear 14 is engaged with this. The rotation angle of the rotating member can be controlled accurately. When the cam gear 14 rotates to a position where the tension pole 7 comes into contact with the magnetic tape 8 at a predetermined angle, the drive plate 17 and the rotary plate 16 interlocking therewith also rotate at a predetermined angle and the cylindrical side surface portion of the drive shaft 2 is rotated. 2a and the band brake 4 are brought into contact with each other to exert a predetermined tension, and when the cam gear 14 is rotated by a predetermined amount in the opposite direction from this position, the position of the tension pole 7 does not move substantially from this position, Only the drive plate 17 and the rotary plate 16 interlocked with the drive plate 17 rotate in the direction in which the tension of the band brake 4 is relaxed, and the cam groove 14a provided on the cam gear 14 and the cam provided on the outer peripheral portion of the cam gear. 14b is formed.

That is, this conventional cam groove 14a plays a role of bringing the back tension arm 5 into contact with the magnetic tape 8 at the time of tape loading and the back tension arm 5 at the time of rewinding, fast-forwarding, stopping, and ejecting. In contrast to this, in the present invention, it is used only for contacting when loading the tape and for separating when ejecting.

With the above-mentioned configuration, it is necessary to rotate the tension pole 7 to a position where the back tension is detected, apply a predetermined amount of tension to the drive shaft 2, and then release the tension by fast-forwarding or rewinding. When the tension occurs, it can be easily achieved by rotating the cam gear 14 by a predetermined amount in the direction opposite to the direction in which the tension is applied, and since the tension pole 7 hardly changes its position, the tape running position is also changed. It has become stable and stable.

In this embodiment, the first cam portion is the cam groove formed in the cam gear, and the second cam portion is the outer shape cam formed in the outer peripheral portion of the cam gear. However, the present invention is not limited to this. Instead, the external cam formed on the outer peripheral portion of the cam gear is used as the first cam portion, and the cam groove formed on the cam gear is used as the second cam portion. There is no problem as long as it is.

[0023]

[Effect of the device]

 According to the present invention, in order to release the back tension when the mode is switched, the back tension arm is not moved, but the second cam portion is formed in the back tension arm driving cam member, and the band brake is formed by this cam portion. This is done by moving the side that was previously fixed, the side opposite to the side that is locked to the back tension arm. By doing this, the back tension can be released without changing the running position of the magnetic tape. Therefore, when the mode is changed, the movement of the tension arm becomes large, the tape becomes slack, and on the contrary, it is in a state where it is stretched with excessive tension, and the rigidity of the band brake makes the band brake straight. This has the advantage that the tension and relaxation of the band brake can be reliably controlled without the problem that the band brake is not completely separated from the drive shaft and the variable load is applied to the drive shaft because of the extension.

Further, by providing a first rotating member for fixing one end of the band brake and a third rotating member for driving the same, the operation direction of this fixed end is made substantially tangential to the drive shaft. Because of the rigidity of the band brake, the band brake tries to extend straight, so that the band brake does not completely separate from the drive shaft, and there is no problem such as uneven rotation due to fluctuating load. Since these members can be compactly arranged around the drive shaft, they can effectively reduce the size and weight of the entire recording / reproducing apparatus. Further, since the second rotating member for adjusting the mounting angle of the first rotating member is provided, the offset between the drive shaft and the band brake can be optimally adjusted at the time of assembly, so that the assembling workability is also very high. Get better.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a tape tension device of the present invention.

FIG. 2 is an operation explanatory view of the tape tension device shown in FIG.

FIG. 3 is an operation explanatory view of the tape tension device shown in FIG.

FIG. 4 is an exploded view of a main part of the tape tension device shown in FIG.

5 is a perspective view of a jig used for operating an offset adjusting mechanism of the tape tension device shown in FIG. 1. FIG.

FIG. 6 is a plan view of a conventional tape tension device.

FIG. 7 is an operation explanatory view of the tape tension device shown in FIG.

[Explanation of sign]

1 chassis (base member) 2 drive shaft 2a cylindrical side face 2b drive unit 3 reel shaft 4 band brake 5 back tension arm 5a guide pin 6 connecting pin 7 tension pole 8 magnetic tape 9 camshaft 10 connecting arm 11 back tension spring (No. 1) One urging means) 12 mounting screw 13 tension arm shaft 14 cam gear 14a cam groove (first cam portion) 14b cam (second cam portion) 15 rotating plate shaft 16 rotating plate (first rotating member) ) 16a mounting hole 16b spur gear 16c long hole 17 drive plate (third turning member) 17a connecting part 17b engaging part 18 drive plate shaft 19 turning plate spring (second biasing means) 20 offset adjusting plate ( Second rotation member) 20a round hole 20b round hole 20c elongated hole 20d screw hole 20e bent portion 2 1 Adjustment screw 22 Jig 22a Handle 22b Round bar 22c Gear

Claims (1)

[Scope of utility model registration request] 1. A back tension arm rotatably provided on a base member, a first urging means for urging the back tension arm in a direction to press the back tension arm against a tape running by rotation of a drive shaft, and a back tension. A band brake with one end attached to the back tension arm so that it is pressed against the drive shaft when the arm rotates in the tape pressing direction, and recording / reproducing, rewinding, fast-forwarding, stop of tape,
A cam member having a first cam portion that is rotated in response to an operation such as an eject and engages with the back tension arm;
A first rotating member that is rotatably provided on the base member, and has the other end of the band brake attached, and a first rotating member that has the same center of rotation as the first rotating member and is opposed to the first rotating member. A second rotating member configured to adjust and fix the angle,
Second urging means for urging the first rotating member in a direction in which the band brake is pressed against the drive shaft, and a second cam portion rotatably provided on the base member and formed on the cam member. And a third rotating member engaged with the second rotating member, wherein the first cam portion rotates the cam member from the recording / reproducing position to the rewinding, fast-forwarding, or stopping position. Keeps the back tension arm in the tape pressing position, and
The back tension arm is formed so as to separate from the tape when the cam member is rotated to the eject position, and the second cam portion is such that the cam member rotates from the recording / reproducing position to the rewinding, fast-forwarding, or stopping position. A tape tension device, characterized in that it is formed so as to rotate the first rotating member in the band brake loosening direction via the third and second rotating members when moved.