JPH0675317B2 - Magnetic recording / reproducing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a magnetic recording / reproducing apparatus in which a magnetic tape is wound around a rotary head cylinder and an image is output, and the magnetic tape can be switched between forward and reverse directions freely. Is.

(Prior Art) When a video signal recorded on a tape is read by a rotating video head in a magnetic recording / reproducing apparatus (hereinafter referred to as a VTR), the tape is fed at a constant speed and an appropriate tape tension is applied. Need to keep.

In the following description, the forward running of the tape means that the tape runs from the supply reel base side to the take-up reel base side via the head cylinder, and the backward running of the tape means the forward running of the tape. Reverse rotation is to drive from the take-up reel stand side to the supply reel stand side via the head cylinder.

Further, the brake on the supply reel base does not act on the supply reel base in a fixed state but softly brakes.

To feed the tape at a constant speed, the tape is run by the rotation of the pinch roller while the tape is pinched by the capstan and the pinch roller, and when the tape is run in the forward direction, a brake is applied to the supply reel base. The tape is used to tension the tape for running.

In order to run the tape in the reverse direction, the supply reel base is rotationally driven. However, if the supply reel base is braked at this time, a large rotational torque is required. A means to release the brake on the platform has also been proposed (Sho 61-25080).

Further, in the conventional VTR, when the tape traveling direction is switched, the pinching pressure between the pinch roller and the capstan is temporarily released in order to stabilize the tape traveling and to adjust the timing of reel drive switching. Is common.

However, with a VTR that has an editing function that allows you to accurately and quickly search for a playback image in frame units and set the recording start point and end point for the tape with high accuracy, the capstan and pinch are used when switching the tape running direction. The tape must be held with the roller pressed.

Such a special VTR is a motor dedicated for reel drive because it is necessary to prevent the video signal loss due to tape slack by timing the capstan tape feeding and reel base winding when switching the tape running direction. Are using.

(Problems to be Solved by the Present Invention) As described above, a VTR having an editing function requires a reel stand drive dedicated motor, resulting in high cost.

Also, when the tape running direction is switched, the tape tension changes greatly due to the difference in the operation timing between the reel drive dedicated motor and the capstan motor, and the difference in the brake operation timing to the supply reel base. There was a problem that the screen was disturbed due to poor contact of the head.

The present invention is a system in which the capstan motor also serves as a motor for driving the reel base. The tape traveling direction is switched while the tape is clamped between the capstan and the pinch roller, and an appropriate tape tension is applied. The purpose of this study is to clarify a magnetic recording / reproducing device that can keep the tape running direction switched.

(Means for Solving the Problems) A magnetic recording / reproducing apparatus according to the present invention comprises a gapstan motor (1
5) also serves as the drive motor for the reel stand, and the capstan (1
The tape was clamped between the pinch roller (16) and the pinch roller (16), and it was hung on the supply reel stand (12) in the magnetic recording device that changes the running direction of the tape from the forward direction to the reverse direction. Brake band (41)
And the back tension post (3
2) equipped with a back tension lever (31) that is spring-biased and pulls one end of the brake band (41), and a spring (43) that biases the stopper (45) and the other end of the brake band (41). The brake release lever (42) being pulled and operates each time the tape running direction is switched, and when the tape is running in the forward direction, the brake release lever urging spring (43) and the brake release lever (42) are pressed. Piece per piece (2
5) and control plate (2) with second contact piece (26)
And a back tension lever urging force reducing spring (73) that is connected to the back tension lever (31) and reduces the urging force of the back tension lever (31) in the tape pulling direction by the operation of the control plate (2). When the tape is switched from the forward running to the backward running, the first hitting piece (25) of the control plate (2) acts on the brake release spring (43), and the spring (43) with respect to the release lever (42). ) Of the release lever (4)
2) is pressed to forcibly rotate the brake release lever (42) in the brake release direction, and the operation of the control plate (2) during this period causes the back tension urging force reducing spring (73).
Is applied to the back tension lever (31) to reduce the tension of the back tension lever against the tape.

(Operation and Effect) When the tape T is running in the forward direction, the control plate (2) is away from the brake release lever (42) and the spring (43) that biases the lever in the pulling direction of the brake band (43). 1 and 5A).

The tension spring (34) for back tension attaches the tension lever (31) to the back tension post (32) on the tension lever (31) with a force that maintains an appropriate tape tension when the tape T is running in the forward direction. If the tape is loose and the tape T is loose, the fixed guides (17) (18) on the chassis
The tape T is pulled in between to apply tension to the tape.

The operation sequence of the brake device (4) when the traveling direction of the tape T is switched from the forward direction to the reverse direction is that the control plate (2) slides toward the release lever (42) side.
The first hitting piece (25) protruding from the lever acts on the spring (43) for urging the brake release lever to put the release lever (42) in the free state (Fig. 5B).

Further, when the control plate (2) slides, the second contact piece (26) on the control plate (2) rotates the rake release lever (42) in a direction to loosen the brake band (41) (second
Figure, Figure 5C).

The tension of the spring (34) of the tension lever (31) becomes stronger according to the amount of slack in the brake band (41), but the tension linked to the tension lever is linked to the slide of the control plate (2). The reduction spring (73) works against the biasing direction of the tension spring (34), and the tape biasing force of the tension lever does not become too strong.

In this state, switching of the tape running direction is completed.

The tape is pinched by the capstan (14) and the pinch roller (16), and the tape is fed by the rotation of the capstan,
Moreover, the reel is supplied with the capstan motor (15) (12)
Also, in the VTR mechanism that also drives the take-up reel base (13), when the traveling direction of the tape T is switched, the timing of rotational force transmission is delayed by the time required to switch the drive system of the reel base.

Therefore, when the tape running direction is switched from the normal direction to the reverse direction, the tape T is loosened between the capstan (14) and the cylinder (11). At this time, as described above, the back tension post (32) acts on the tape T, and the tape T
To eliminate the looseness (Fig. 2).

When the tape is wound on the supply reel stand side, the brake release lever (42) is pressed by the control plate (2) to rotate in the loosening direction of the brake band (41) as described above. Almost no brake band is used, and it does not become a load for the winding operation by the supply reel base (12).

Further, when the tape running direction is switched from the reverse direction to the forward direction, the above-described reverse operation is performed, the control plate (2) is separated from the brake release lever (42), and the control plate (2) returns according to the return operation. The urging force of the brake release lever spring (43) gradually acts on the release lever (42), and the release lever (42) gradually rotates in a direction to brake the supply reel base (12), as shown in FIG. The tape is returned to the normal tape running state shown in.

As described above, according to the present invention, when the tape running direction is switched from the forward direction to the reverse direction, the brake for the supply reel base is released, and the reel base can be rotationally driven with a small torque.
In addition, the tension lever can eliminate the slack of the tape while the brake on the supply reel base is released, and the spring force of the tension lever can be reduced by the action of the tension reducing spring to provide the optimum tension to the tape. .

(Example) As an example of the present invention, a home magnetic recording / reproducing apparatus (hereinafter referred to as VTR) generally known as a video will be described.

Figures 1 and 2 show the VTR mechanism as seen from the top with the case removed. Figure 1 shows the tape running in the forward direction and Figure 2 shows the tape running in the reverse direction. ing.

Head cylinder (11), supply reel stand (12), take-up reel stand (13), capstan (14), on chassis (1),
A capstan motor (15) and a pinch roller (16) are arranged in a known manner, and a pair of tape leading guides (19) (19a) are slidably provided between both sides of the head cylinder (11) and the supply reel stand (12). ) Is provided.

A swing idler device (5) and a supply reel stand reverse rotation preventing device (6) are provided between the supply reel (12) and the take-up reel stand (13).

A control plate (2) is slidably provided on the chassis (1) in parallel with an imaginary line L connecting the supply reel base (12) and the take-up reel base (13), and the control lever (2) is provided with an intermediate lever. (2
1), first auxiliary control plate (22) and second auxiliary control plate (23)
The positive cam (24) is linked via the.

A band brake device (4) is connected to the supply reel base (12), and a tape tension holding device (3) is connected to the band brake device (4).

A tape tension reducing device (7) is provided between the tape tension holding device (3) and the control plate (2).

Straddling the supply reel stand (12) and the take-up reel stand (13),
A tape cassette (not shown) is loaded.

A tape leading guide (19) (19a) pulls out a tape from a tape cassette and winds it around a head cylinder (11). Each of a recording mode, a normal reproduction mode, a fast-forward reproduction mode, a slow reproduction mode, and a frame advance reproduction mode. In mode, the tape runs in the forward direction.

In each of the reverse playback mode, the reverse fast forward playback mode, the reverse slow playback mode, and the reverse frame forward playback mode, the tape runs in the reverse direction.

When the running direction of the tape T is changed, the positive cam (24) rotates to operate the auxiliary control plates (22) (23) and the intermediate lever (21), and the control plate (2) in FIG. Slides left and right.

By the sliding motion of the control plate (2), the swing idler device (5), the supply reel stand reverse rotation preventing device (6), the band brake device (4) to the supply reel stand (12), and the tape tension holding device (3) ) And the tape tension reducing device (7) operate.

In the VTR mechanism, the capstan motor (15) also serves as a drive motor for the supply reel base (12) and the take-up reel base (13).

Also, when the traveling direction of the tape T is switched in the recording and the various reproduction modes, the tape T is set to the capstan (1
4) and pinch roller (16) are nipped.

The configuration of each device will be described below together with the operation.

In the following description, each lever is rotatably arranged in a plane parallel to the chassis (1).

Band Brake Device and Tape Tension Holding Device In FIG. 1, a back tension lever (31) is provided on the left side of the supply reel base (12), and a brake release lever (42) is provided between the lever and the control plate (2). One end of the brake band (41) that is deployed and hangs around the supply reel stand (12) about half way is on the base end side of the back tension lever (31), and the other end is on the free end of the brake release rehearsal (42). Installed.

The back tension lever (31) rotates about a fulcrum (33) and is urged counterclockwise by a back tension tension spring (34) to pull the brake band (41).

The brake release lever (42) is biased counterclockwise by the torsion spring (43) and hits the stopper (45) on the chassis (1).

As shown in FIG. 5A, one end of the torsion spring (43) is inserted into the hole (10) of the chassis (1) and locked, and is wound around the fulcrum shaft (44) of the brake release lever (42) and the other end. Penetrates through a long hole (47) opened at the base end side of the lever and is exposed to the outside.

When the tape T is running in the forward direction, the control plate (2) is separated from the brake release lever (42) and the torsion spring (43) (Figs. 1 and 5A).

The operation sequence of the brake device (4) when the traveling direction of the tape T is switched from the forward direction to the reverse direction is that the control plate (2) is projected to the left end of the control plate (2) while sliding to the left. The hit piece (25) pushes one end of the torsion spring (43) to put the brake release lever (42) in a free state (Fig. 5B).

Further, when the control plate (2) slides to the left, the second contact piece (26) on the control plate (2) directly presses the brake release lever (42) to move the lever (42) clockwise. Rotate to loosen the brake band (41) (Figs. 2 and 5)
(Figure C). In this state, switching of the tape running direction is completed.

The tension spring (34) for back tension moves the tension lever (31) counterclockwise with respect to the back tension post on the tension lever (31) with a force that maintains proper tape tension when the tape T is running in the forward direction. If it is biased and the tape T loosens, the fixed guide (17) on the chassis
(18) Pull the tape T in between to apply tension to the tape.

A supply reel stand (12) and a take-up reel stand (1) are driven by a capstan motor (15) via a conventional swing idler device.
With the VTR mechanism that also drives 3), the timing of torque transmission is delayed by the amount of swing motion of the swing idler device when switching the running direction of the tape T.

Therefore, when the tape running direction is switched from the normal direction to the reverse direction, the tape T is loosened between the capstan (14) and the cylinder (11). At this time, the back tension post (32) acts on the tape T to eliminate the looseness of the tape T (Fig. 2).

FIG. 6 shows the relationship of forces acting on the back tension lever (31) when the tape is in the forward direction. When the tape is running in the forward direction, the counterclockwise moment Msp due to the load Fsp of the back tension tension spring (34)
The clockwise moment Mt due to the tape tension Ft, and the pulling force of the back tension brake band (41)
A clockwise moment Mb by Fb acts on the back tension lever (31).

At this time, the back tension lever (31) is in a balanced state and the following equation is established.

Mt + Mb = Msp The brake release lever (42) attached to one end of the back tension brake band (41) is the stopper (45).
The conditional expression when it is pressed into a fixed state is as follows.

Fto> Fb / e ^μθ Fto is generated by the torsion spring (43),
μ represents a coefficient of friction between the back tension brake band (41) and the supply reel base (12), and θ represents a winding angle with respect to the supply reel base.

By setting the load of the torsion spring (43) appropriately, when the tape tension Ft becomes extremely small,
The condition for fixing the brake release lever (42) collapsed, and Fto <Fb / e ^μθ , and the brake release lever (42)
Is operated, the back tension lever (31) is also rotated in the tape direction to apply an appropriate tension to the tape.

When the tape T is wound on the side of the supply reel stand, the brake release lever (42) is pressed by the control plate (2) to rotate in the loosening direction of the brake band (41) as described above. Almost no brake is applied and it does not become a load for the winding operation by the supply reel base (12).

Further, when the tape running direction is switched from the reverse direction to the forward direction, the above-described reverse operation is performed, the control plate (2) is separated from the brake release lever (42), and the control plate (2) returns according to the return operation. The biasing force of the torsion spring gradually acts on the release lever (42), and the release lever (42) is gradually rotated counterclockwise to gradually brake the supply reel base (12). The tape is returned to the normal tape running state shown in.

As described above, the momentary counterclockwise rotation of the brake release lever (42) due to the spring force can be suppressed, and the back tension lever (31) can be passed through the brake band (41).
Does not abruptly rotate in the clockwise direction, so that it is possible to prevent the tape from being extremely loosened and prevent the screen from being disturbed due to a poor contact of the magnetic head with the tape.

Back tension reducing device It is desirable that the tape tension be the same when the tape is running in the forward direction and when running in the reverse direction. The tape tension when traveling in the opposite direction is stronger than the tape tension when traveling in the opposite direction.

The back tension reducing device works in cooperation with the tape tension driving device to make the tensions of the tape in the forward direction and in the reverse direction as equal as possible.

Under the chassis (1), set the tension lever (3
A back tension reducing lever (71) and a relay lever (7) formed in a substantially V shape between the control plate (1) and the control plate (2), respectively.
4) is deployed and both levers (71) (74) are control plates (2)
It works in conjunction with the slide of.

As shown in FIG. 9, the tension reducing lever (71) rotates about a fulcrum (72), and the first free end (77a) and the tension lever (31) are connected by a tension spring (73). There is.

The spring connecting piece (31a) of the tension lever (31) is bent downward, and penetrates through the long hole (1a) formed in the chassis (1) and protrudes below the chassis (1) as shown in FIG. The spring (73) is hooked on the connecting piece (31a).

The spring connecting piece (31a) of the tension lever (31) is located on the counterclockwise transition path of the second free end (77b) of the tension reducing lever (71).

At the first free end (79a) of the relay lever (74), the pin (7
6) is projectingly provided, and the pin is slidably fitted in a through elongated hole (70) formed in the vicinity of the rotation fulcrum (72) of the tension reducing lever (71).

At the second free end (79b) of the relay lever (74), the protruding shaft (7
8) is projected, and the projecting shaft (78) penetrates the through window hole (1b) of the chassis (1) shown in FIG. 1 and is exposed above the chassis.

On the control plate (2), the protrusion shaft (78) of the relay lever (74) is pushed to rotate the lever clockwise.
A second cam surface (27b) protruding higher than the first cam surface is formed on the left side of the cam surface (27a) and the first cam surface.

When the tape T is running in the forward direction, the protruding shaft (78) of the relay lever (74) moves between the first cam surface (27a) and the second cam surface (27b) of the control plate (2) as shown in FIG. It fits in the recess between them.

In the above state, the back tension reducing spring (73) has a free length, and the back tension reducing device (7) is
Does not affect tape tension.

When the running direction of the tape switches from the forward direction to the reverse direction,
By sliding the control plate (2) to the left, the protruding shaft (78) of the relay lever (74) of the tension reducing device (7) rides on the first cam surface (27a) of the control plate (2) and the fulcrum (75). )
The center of the back tension reducing lever (71) rotates in the clockwise direction about the fulcrum (71) as shown by the chain line in FIG.

At this time, the back tension reducing spring (73) is stretched, and the stretching force of the spring acts against the tension spring (34) of the back tension lever (31), causing the back tension post (32) to move to the tape T. Weakens the force acting on.

The force of the back tension reducing spring (73) is as shown in FIG. 9 when the reducing lever (71) rotates counterclockwise to extend the spring, as shown by the chain line in FIG. It corresponds to the moment Mb in the clockwise direction due to the force Fb pulled by the brake band (41).

As explained about the tape tension holding device, Msp = Mt + Mb is always satisfied when the tape is running in the forward direction, and the tape is given a substantially constant tension, but the running direction of the tape was switched from the forward direction to the reverse direction. When the control plate (2) is moved to the left at the time, the brake release lever (42) is rotated clockwise, and the brake band (4)
1) loosens.

Since the brake band (41) is loosened, Fb = 0 ∴Mb = 0 and Msp> Mt, but as described above, the tension lever (31) corresponds to the looseness of the brake band and the back tension reducing spring (73). ) By the clockwise force (Mb). Therefore, the back tension lever (31) is almost Msp'-Mb (where Msp 'is the fulcrum (33) of the back tension lever (31) due to the spring force when Msp is weakened by the back tension reducing spring (73). ) Around moment) always works to absorb tape slack at any time, and since the brake band (41) releases the supply reel base (12), the tape can be wound with a small torque.

In the unloading operation of the tape in which the tape wound around the cylinder (11) is stored in the cassette (not shown) on the reel stand, the control plate (2) slides to the right side as shown in FIG. 3, and the relay lever ( The protruding shaft (78) of 74) rides on the second cam surface (27b), and the lever (74) pivots largely clockwise. Along with that, the back tension reducing lever (71) pivots largely in the counterclockwise direction, and the reducing lever (7
The second free end (77b) of 1) is the back tension lever (3
The spring connecting piece (31a) of 1) is pushed, and thereby the back tension lever (31) rotates clockwise around the fulcrum (33), and the free end of the lever (31) moves to the tape leading guide ( Located on the transition road of 19a).

While the tape leading guide (19a) moves to the reel stand side, press the back tension lever (31) to move the back tension lever (31) to a position where it does not hinder the storage of the tape T in the tape cassette. Rotate in the direction (Fig. 4).

Swing Idler Device The swing idler device (5) shown in FIG.
A swing lever (51) is provided between the supply reel stand (12) and the take-up reel stand (13), and relay gears (57) (58) are respectively provided between the reel stand and the lever (51). Has been deployed.

An idler gear (53) is provided on the swing lever (51), and the idler gear (53) is a gear rotation transmission means (5).
9) and the capstan motor (1) via the belt (54)
It is linked to 5).

When the capstan motor (15) is switched between forward and reverse rotation, a rotational frictional force acts between the swing lever (51) and the idler gear (53), and the lever vibrates around the fulcrum (52). Operation, the idler gear (53) selectively meshes with the two relay gears (57) (58), and the supply reel stand (12)
Alternatively, the take-up reel stand (13) is rotationally driven in the take-up direction.

As shown in FIGS. 7 and 8, a leaf spring (55) is attached to the swing lever (51), the base end of the leaf spring (55) is fixed to the swing lever (51), and the free end is idler. Suitable for gear mounting side.

A protruding piece (56) is bent and formed upward at the end of the swing lever (51) where the idler gear is attached.

The distance between the protrusion (56) of the swing lever (51) and the rotation fulcrum (52) of the lever is such that the free end of the leaf spring (55) and the lever (5
It is longer than the distance between the rotation fulcrum (52) in 1).

The control plate (2) has a leaf spring (55) and a protrusion (5).
6) A first protrusion (28a) and a second protrusion (28b) that can be engaged with
Is bent upward.

FIG. 1 shows the state of the swing idler device (5) when the tape T is running in the forward direction. The swing lever (5) tilts to the take-up reel stand (13) side, and the idler gear (53) winds. It meshes with the relay gear (58) on the reel stand side.

The first protrusion (28a) of the control plate (2) is the swing lever (51).
The projecting piece (56) and the second projection (28b) of the control plate (2) are just before contacting the leaf spring (55).

When the running direction of the tape T is switched from the forward direction to the reverse direction,
The capstan motor (15) temporarily stops, and the control plate (2) slides leftward during this period. At this time, the first protrusion (28a) of the control plate (2) is the protrusion (5) of the swing lever (51).
6) Press to force the swing lever (51) to rotate clockwise.

As a result, the idler gear (53) will move to the take-up reel stand (1
Move away from the 3) side relay gear (58). At this time, the second protrusion (28b) of the control plate (2) is also pressing the leaf spring (55).

The distance between the protrusion (56) of the swing lever (51) and the rotation fulcrum (52) of the lever is such that the free end of the leaf spring (55) and the lever (5
Since it is longer than the distance between the rotation fulcrum (52) of (1), when the swing lever (51) rotates in the clockwise direction, the protruding piece (56) immediately causes the protrusion (56) to move to the first protrusion (28a) of the control plate (2). ), The second protrusion (28b) of the control plate (2) independently keeps pressing the leaf spring (55), and the swing lever (51) rotates clockwise (7th).
Figure).

Further, the control plate (2) slides to the left, the swing lever (51) continues to rotate clockwise, and the idler gear (53)
Meshes with the relay gear (57) on the supply reel stand side (second
Figure).

The swing lever (51) receives a rotational force in the clockwise direction via the leaf spring (55), and if the idler gear (53) and the relay gear (57) are forced to engage with each other, the leaf spring (55) will move. As it flexes and absorbs shock, it does not damage the tooth tips.

By the series of operations of the swing idler device (5), the idler gear (53) and the relay gear (57) are surely meshed at the completion of the switching of the tape T to the reverse running mode, and the supply reel Capstan motor (15) on the table (12)
The rotation of the tape can be transmitted, and the tape T can be run in the opposite direction and wound on the supply reel stand (12).

As described above, when the tape running direction is switched from the forward direction to the reverse direction, the swing lever (51) is forcibly rotated clockwise by the control plate (2), so that the idler gear (53) and the take-up lever are wound. Even if the relay gear (58) on the reel stand side is strongly meshed, the mesh can be quickly released, and the mesh between the idler gear (53) and the relay gear (57) on the supply reel stand side is a plate. It can be done without force through the spring (55).

When the traveling direction of the tape T is switched from the reverse direction to the forward direction, the control plate (2) slides to the right prior to the switching of the rotation direction of the capstan motor (15).

Therefore, the leaf spring (52) and the protruding piece (56) of the swing lever (51) do not collide with the first protrusion (28a) and the second protrusion (28b) of the control plate (2).

Further, when the reverse running is switched to the forward running, the swing lever (51) is rotated counterclockwise from the state of FIG. 2 so that the idler gear (53) is on the take-up reel stand (13) side. Although it engages with the relay gear (58) of the tape, the winding timing is delayed during that time, and the tape T is loosened between the capstan (14) and the take-up reel stand (13). )
Since the tape is pinched by the pinch roller (16) and the tape is not loosened on the cylinder (11) side, the video signal is not lost.

When switching between modes that are not related to recording or playback, such as fast-forward / rewind mode, stop mode, and eject mode,
Since the control plate (2) operates on the right side of the forward traveling of FIG. 1, the first protrusion (28a) and the second protrusion (28b) of the control plate (2) are attached to the swing lever (51). The swing lever (51) does not affect the capstan motor (15) as before.
The normal swinging motion is performed by transmitting the rotational torque of.

Of course, a rubber idler may be used instead of the idler gear, and a relay roller may be used instead of the relay gear, so that the rotational force can be transmitted by the friction between the rubber idler and the relay roller.

Supply reel base reverse rotation preventing device A lock gear (61) is provided on the relay gear (57) on the side of the supply reel base (12) coaxially with the gear. A one-way clutch (not shown) is interposed between the lock gear (61) and the relay gear (57), and the log gear (6
In the state where 1) is locked, the relay gear (57) is allowed to rotate clockwise or is prevented from rotating counterclockwise.

The control plate (2) is provided with a lock lever (63) which is means for locking the lock gear (61).

The lock lever (63) has its base end pivotally supported by the control plate (2),
At the free end facing the lock gear (61) side, the lock gear (6
A lock claw (65) which can be engaged and disengaged is projectingly provided in (1), a spring plate (67) is projectingly provided at a base end thereof, and a contact portion (66) is projectingly provided at a tip end of the spring plate.

On the chassis (1), a pin (64) is projectingly provided on the left side of the hitting portion (66).

When the traveling of the tape T is switched from the forward direction to the reverse direction, the second
As shown in the figure, when the control plate (2) is slid to the left, the contact portion (66) of the lock lever (63) hits the pin (64), which causes the lock lever (63) to rotate clockwise and lock. The claw (65) engages with the lock gear (61) to lock the lock gear.

The lock claw (65) is connected to the lock gear (6) via the spring plate (67).
Since it is urged to the 1) side, no excessive force is applied when the lock lever (63) and lock gear (61) are engaged.

As described above, the lock gear (61) is locked during the transition of the traveling direction of the tape T from the forward direction to the reverse direction, and in this state, in this state, as described above, the relay gear on the supply reel base (12) side. (57) is allowed to rotate only in the clockwise direction and is prevented from rotating in the counterclockwise direction. Therefore, although the supply reel stand (12) meshed with the relay gear (57) rotates counterclockwise, that is, in the tape T winding direction, it rotates clockwise, that is, the tape T moves from the supply reel stand side. Rotation in the direction of withdrawal is blocked.

As a result, as described above, the slack of the tape that occurs when the running direction of the tape is switched from the forward direction to the reverse direction is pulled by the rotation of the tension lever (31) between the guides (17) and (18). When absorbing, the tape is not pulled out from the tape supply reel stand side.

The present invention is not limited to the configuration of the above embodiment, and various modifications can be made within the scope of the claims.

[Brief description of drawings]

FIG. 1 is a plan view of the VTR mechanism in the forward running state of the tape, FIG. 2 is a plan view of the same running tape in the reverse direction, FIG. 3 is a plan view of the same tape being unloaded, and FIG. FIG. 5A, FIG. 5B, and FIG. 5C are explanatory views of the operation sequence of the brake release lever with respect to the operation of the control plate, and FIG. 6 is a view showing the tape tension holding device. A plan view, FIG. 7 is a plan view of the idler device, FIG. 8 is a perspective view of an essential part of a swing lever and a control plate, and FIGS. 9 and 10 are operation explanatory views of a back tension reducing device. (12) ... Take-up reel base, (13) ... Supply reel base (2) ... Control plate, (4) ... Brake device (5) ... Swing idler device (6) ... Supply reel base reverse rotation prevention device (7) ... Back tension reducing device

Claims (1)

[Claims] 1. A capstan motor (15) also serves as a drive motor for a reel base, and when the tape is pinched between the capstan (14) and the pinch roller (16), the tape is run in the normal direction. In the magnetic recording device that shifts from the opposite direction to the opposite direction, the brake band (41) hung on the supply reel base (12)
And the back tension post (3
2) equipped with a back tension lever (31) that is spring-biased and pulls one end of the brake band (41), and a spring (43) that biases the stopper (45) and the other end of the brake band (31). The brake release lever (42) being pulled and operates each time the tape running direction is switched, and when the tape is running in the forward direction, the brake release lever urging spring (43) and the brake release lever (42) are pressed. Piece per piece (2
5) and control plate (2) with second contact piece (26)
And a back tension lever urging force reducing spring (73) connected to the back tension lever (31) and reducing the urging force of the back tension lever (31) in the tape pulling direction by the operation of the control plate (2). When the tape is switched from the forward running to the backward running, the first hitting piece (25) of the control plate (2) acts on the brake release spring (43), and the spring (43) with respect to the release lever (42). ) Of the release lever (4)
2) is pressed to forcibly rotate the brake release lever (42) in the brake release direction, and the operation of the control plate (2) during this period causes the back tension urging force reducing spring (73).
A magnetic recording / reproducing apparatus characterized in that the back tension lever (31) is acted on to reduce the pulling force of the back tension lever against the tape.