JPH07121937A - Reel-stand braking device - Google Patents

Abstract

PURPOSE:To prevent a tape from being damaged by a method wherein, when a stop instruction is issued during a fast-forward operation, a first motor continues driving until the first motor operates a brake by a control circuit. CONSTITUTION:Even when a stop instruction is issued in a fast-forward mode, a capstan-motor control circuit does not issue immediately a stop instruction, and a capstan motor 1 continues driving for a prescribed time. On the other hand, as soon as a stop instruction is issued, a mode motor 20 starts turning, and it moves a main rod 8 via a gear train 2, a main cam gear 21 and a main cam lever 23. When the rod 8 is moved, brake pins 11a, 12a are detached from a cam face 8b on the rod 8, and respective brakes start hitting a take-up reel stand 7 and a feed reel stand 14. Simultaneously with this operation, a regulation lever pin 9a is pressed by a cam face 8a on the rod 8, a regulation lever 9 is turned, and an oscillating gear 5 is separated forcibly from the reel stand 7. After that, the respective brakes are operated, and they act so as to stop the reel stands 7, 14. Then, the motor 1 is stopped by the control circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in video tape recorders, digital audio tape recorders, etc.
The present invention relates to a reel stand braking device.

[0002]

2. Description of the Related Art Recently, in video tape recorders, digital audio tape recorders and the like, there is a strong demand for shortening the fast-forwarding / rewinding time and shortening the image output time after the fast-forwarding / rewinding. Along with this, a reel stand brake device that brakes the supply / take-up reel stand by increasing the tape speed during fast-forwarding / rewinding and increasing the tension increase coefficient by fast-forwarding / rewinding in a state where the cylinder is fully loaded. Also, high braking characteristics are required.

The following two points must be noted in the structure of the reel stand brake device. An example will be described when shifting from the fast-forward mode to the stop mode. First
Also, it prevents tape damage.

When stopping from fast feed, a large brake torque (biting torque) is applied to the supply reel base, and a small brake torque (escaping torque) is applied to the take-up reel base.
Takes. Therefore, the supply reel stand tends to stop early and the take-up reel stand tends to stop late, but when there is more tape on the take-up reel stand, the inertial force increases and the tape tension increases. Since the tape runs helically around the inclined post, there is a component of tape tension in the vertical direction (axial direction) of the post. If the tension becomes excessive, this force also increases and the tape is pressed against the flange of the guide post. Especially in the case of thin tape (180 minutes tape), tape deformation and damage may occur due to low tape rigidity.

Second, it is necessary to prevent the slack of the tape. When the supply reel base has a lot of tape and has a large inertial force, and the take-up reel base has a small inertial force, when stopping from the fast-forward mode, the supply reel base is hard to stop even if a large biting torque is applied, Even with a small escape torque, the take-up reel stand easily stops. Therefore, the tape tends to sag. If the tape sags, it will come off the guide post flange and fall. As a result, when the tape is wound and stretched next time, the tape is pressed against the flange of the guide post, and the tape is deformed or damaged.

In this way, tape damage and tape slack are prevented from the beginning to the end of winding of the tape cassette, and the tape flow amount from the receipt of the stop command to the actual stop of the tape is reduced. In this way, each company proposes a mechanism for setting the brake torque and the escape torque, and for setting the brake.

Fast forward / rewind of a general magnetic recording / reproducing apparatus has a structure in which power is transmitted from a capstan motor for driving a capstan to a reel stand and a tape is wound on the reel stand. With such a configuration, fast forward
When shifting from the rewind mode to the stop mode, the inertia of the capstan motor is transmitted to the reel stand, so the actual inertia of the take-up reel stand becomes large, and tape damage easily occurs, The flow rate of the flow increases.

As means for solving such a problem, there has been proposed a structure in which the capstan motor and the reel stand are forcibly disconnected in the stop mode as disclosed in Japanese Utility Model Laid-Open No. 02-8277. . FIG. 7 is a plan view of a main part around a reel stand of a conventional example. Briefly explaining the configuration,
When the brake member 100 operates in the stop mode, the contact portion 101 of the brake member 100 contacts the swing gear 103 rotatably provided on the rotating arm 102, separates the swing gear 103 from the reel base 104, and causes the capstan to move. The power of a motor (not shown) is separated from the reel base 104.

Next, the operation will be described. When a stop command is issued during high-speed running (fast-forward operation), the capstan motor drive is immediately cut off, and the tape tension during running gradually decreases. (FIG. 6) Until the brake is applied to the reel base 104 until it stops, the braking force of the escape torque and the load due to the tape tension work to stop the reel base 104, but the tape tension is low. The load for stopping the reel stand 104 is small, and the reel stand 104 still has a considerable inertial force (rotational energy).

Therefore, even if the supply reel base (not shown) bites into the supply reel base and the supply reel base stops immediately, the tape tension becomes large due to the inertial force (rotational energy) of the reel base 104 (see FIG. 7), tape damage will occur.

[0011]

As described above, the conventional structure has a major problem that the tape tension increases momentarily when the fast-forward mode is changed to the stop mode, resulting in tape damage. . In particular, when a solenoid does not need to be used for the brake operation and it takes a relatively long time to operate the brake (several hundreds of milliseconds), or when the moment of inertia of the capstan motor is small, the tendency is remarkable.

[0012]

In order to solve the above-mentioned problems, a reel base brake device of the present invention has a pair of supply / winding units each having an engaging portion for engaging with a tape reel and integrally provided with a gear portion. A take-up reel stand, a pendulum gear that selectively meshes with one of the gear parts of the pair of supply / take-up reel stand, and a first motor that drives the supply / take-up reel stand via the pendulum gear, A mode switching member that moves according to each operation mode, a second motor that drives the mode switching member, a reel brake that interlocks with the mode switching member to brake a pair of supply / take-up reel bases substantially at the same time, and a mode. A release member that interlocks with the switching member to release the meshing between the pendulum gear and the gear portion of the supply / take-up reel base substantially at the same time when the reel brake is braked, and the fast-forward / rewind mode shifts to the stop mode. Do In, until meshing with at least pendulum gear and the supply / take-up reel base gear portion is released, the first
It is composed of a control circuit that continues to drive the motor.

[0013]

According to the present invention, the tape tension is not lowered because the control circuit continues to drive the first motor until the brake is operated by the control circuit when a stop command is issued during the fast-forward operation. While the brake is operating, a predetermined tape tension and escape torque are applied to the take-up reel stand, and the take-up reel stand has less inertial force (rotational energy). At this time, since the inertial force of the first motor is separated from the reel base by the release member, the inertial force of the take-up reel base is further reduced. Therefore, the tape tension does not become extremely high even when the bite torque acts on the supply reel stand, and the occurrence of tape damage can be prevented.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a timing chart when the reel base brake device of the present invention is shifted from a fast-forward mode to a stop mode, FIG. 2 is a plan view of the reel base brake device, FIG. 3 is a side view of essential parts of the reel base brake device, and FIG. FIG. 5 is an operation explanatory view showing the main part of the reel base brake device in the transition from the fast forward / rewind mode to the stop mode, and FIG. 5 is a schematic block diagram in which the capstan motor and the mode motor are driven. .

First, the overall structure will be described with reference to FIG.
A belt 2 for transmitting a driving force is wound around a capstan motor 1 which is a driving source and a center gear 3. The center gear 3 rotatably supports one end of a pendulum arm 4, and the other end rotatably supports the pendulum gear 5 around a pendulum gear shaft 5a.

A PLAY gear arm 15 is rotatably provided around the axes of the take-up reel base 7 and the supply reel base 14, and a PLAY gear 16 is rotatably supported on a PLAY gear shaft 15a provided at one end thereof. is doing. PLAY
The gear arm 15 is provided with a restriction pin receiving portion 15b that engages with a restriction pin 17 fixed to a chassis (not shown). Further, the regulating arm 1 is attached to the PLAY gear shaft 15a.
9 is engaged with the guide groove 19a, and the follower pin 19b of the regulating arm 19 is engaged with the arm cam surface 8d of the main rod 8. A movement guide groove 19c is formed in the regulation arm 19, and the guide pin 18 provided on the chassis 18 is provided.
Guided and supported by a.

Small gear 5c of center gear 3 and pendulum gear 5
Is always in mesh, and the pendulum gear 5 is the capstan motor 1
Depending on the direction of rotation of, it can be rotated left and right. FF
The idler gear 6 is rotatable about an axis fixed to the chassis, and the take-up reel gear 7a or the supply reel gear 14a is always meshed. Also, PLAY gear 1
6 and the take-up limiter gear 7b or the supply limiter gear 14b are always meshed with each other. A take-up tape reel (not shown) is provided on the take-up reel base 7 integrally formed with the take-up reel gear 7a, and a supply-side tape reel (not shown) is provided on the supply reel base 14 integrally formed with the supply reel gear 14a. ) Are engaged with each other. 2 state (fast forward /
In the rewind mode), the output of the capstan motor 1 is the center gear 3, the small gear 5c of the swing gear 5, the large gear 5b,
It is transmitted to the take-up reel stand 7 via the FF idler gear 6 and the take-up reel stand gear 7a. When the PLAY gear arm 15 rotates (not shown), the output of the capstan motor 1 is the center gear 3 and the small gear 5 of the swing gear 5.
c, the PLAY gear 16 and the take-up limiter gear 7b to transmit the take-up reel stand 7. Although not shown, a torque limiter is provided between the take-up limiter gear and the take-up reel base.

The mode motor 20 to the main cam gear 21
Up to the gear train 22 is configured. Main cam gear 2
A cam pin 23a provided at one end of the main cam lever 23 is engaged with the cam groove 21a provided at 1, and a rod pin 23b provided at the other end is a main rod that is a mode switching rod that moves to the left and right when the mode is changed. The guide grooves 8c of 8 are engaged. The main rod 8 has a lever cam surface 8a and a brake cam surface 8b.

The take-up side brake 11 and the supply side brake 12 are pivotally supported near the take-up reel base 7 and the supply reel base 13, respectively, and a spring hook portion 1 provided at one end of each of them.
Brake springs 13 are wound around 1b and 12b, and are attracted to each other, and the take-up side brake pin 11a and the supply side brake pin 12a are in contact with the main rod 8.

A spring hooking portion 9b is provided at one end of a pair of regulating levers 9 having a rotation support shaft, and a regulating lever spring 10 is stretched between them and pulled toward each other.
The regulating lever 9 is provided with a lever pin 9a. The restriction lever 9 is supported at a position where it can contact the pendulum gear shaft 5a protruding from the pendulum gear 5, as shown in FIG.

Further, as shown in FIG. 5, the mode command detected by the mode detection circuit 50 is transmitted to the capstan motor control circuit 51, and the capstan motor drive circuit 52.
Drives the capstan motor 1. Similarly, the mode command detected by the mode detection circuit 50 is transmitted to the mode motor control circuit 53, and the mode motor drive circuit 54 drives the mode motor 20.

The operation of the reel stand device configured as described above will be described below. Since the present invention is characterized by the operation when shifting from the fast forward / rewind mode to the stop mode, only that operation will be described. Further, since the operation of shifting from the fast-forward mode to the stop mode and the operation of shifting from the rewinding mode to the stop mode are basically the same, only the transition operation from the fast-forward mode to the stop mode will be described. As shown in FIG. 1, even if a stop command is issued during the fast-forward mode, the capstan motor control circuit 51 does not immediately issue a stop command, so the capstan motor 1 does not stop immediately and the Continue driving for time T0. On the other hand, when the stop command is issued to the mode motor 20, the mode motor control circuit 53 immediately issues a stop command, so that the mode motor 20 starts rotating immediately, and the main rod 8 passes through the gear train 22, the main cam gear 21, and the main cam lever 23. To move. When the main rod 8 moves from FIG. 4a to FIG. 4b, the brake pin 1 provided on each brake
Since 1a and 12a are disengaged from the cam surface 8b of the main rod 8, the respective brakes start to hit the take-up reel base and the supply reel base. (FIG. 4b) At almost the same timing as this, the regulating lever pin 9a is attached to the cam surface 8a of the main rod 8.
Since it is pushed by, the regulation lever 9 rotates and the swing gear 5
Is forcibly separated from the take-up reel stand 7. After that, the respective brakes operate to work to stop the take-up reel base 7 and the supply reel base 14. (FIG. 4c) Next, the capstan motor 1 is stopped by the control circuit.

On the other hand, looking at the tape tension according to the above operation (FIG. 1), the capstan motor 1 continues to be driven even if a stop command is issued, so the tension in the fast-forward mode is maintained. When the brakes are applied, the tape tension is not lowered, so the rotational energy of the take-up reel stand 7 is suddenly decreased and the tension is increased a little, but it is considerably smaller (B) than the maximum tension A of the conventional example. You can Therefore, the fast-forward mode can be switched to the stop mode without causing tape damage. By appropriately selecting the time T0 from when the stop command is issued until the drive of the capstan motor 1 is stopped, the above-mentioned contents can be obtained even if there is a difference in inertia of the capstan motor or load variation of the traveling system. Can be achieved.

[0024]

As described above, according to the present embodiment, at the time of shifting from the fast-forward / rewind mode to the stop mode, at least the meshing of the pendulum gear and the gear portion of the supply / take-up reel stand is released. Since the capstan motor continues to be driven until it starts, the tension before the brake is actuated is kept high, so that the rotation energy of the take-up reel is gradually consumed by the brake and tape tension. The tape tension can be kept low and the occurrence of tape damage can be prevented.
Also, since the swing gear is forcibly separated from the reel stand, it is possible to suppress the occurrence of tape damage regardless of the magnitude of the moment of inertia of the capstan motor,
Its practical effect is great.

[Brief description of drawings]

FIG. 1 is a diagram showing an operation timing chart of a reel stand brake device according to an embodiment of the present invention.

FIG. 2 is a plan view of a reel stand brake device according to an embodiment of the present invention.

FIG. 3 is a side view of an essential part of a reel stand brake device according to an embodiment of the present invention.

FIG. 4a is an operation explanatory diagram of a reel base braking device according to an embodiment of the present invention. FIG. 4b is an operation explanatory diagram of the reel base braking device. FIG. 4c is an operation explanatory diagram of the reel base braking device.

FIG. 5 is a schematic block diagram according to an embodiment of the present invention.

FIG. 6 is a diagram showing an operation timing chart of a reel stand braking device in a conventional example.

FIG. 7 is a plan view of a main part of a reel stand brake device in a conventional example.

[Explanation of symbols]

 1 Capstan motor 3 Center gear 4 Pendulum arm 5 Pendulum gear 6 FF idler gear 7 Take-up reel stand 7a Take-up reel gear 8 Main rod 8a Lever cam surface 8b Brake cam surface 9 Restricting lever 10 Restricting lever spring 11 Take-up side brake 11a Take-up side Brake pin 12 Supply side brake 12a Supply side brake pin 13 Brake spring 14 Supply reel stand 14a Supply reel gear 50 Mode detection circuit 51 Capstan motor control circuit 52 Capstan motor drive circuit 53 Mode motor control circuit 54 Mode motor drive circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsutoshi Nagao 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] 1. An engaging portion engaging with a tape reel,
A pair of supply / take-up reel bases integrally provided with gears, a pendulum gear that selectively meshes with any of the gears of the pair of supply / take-up reel bases, and the pendulum gears A first motor that drives the supply / take-up reel base, a mode switching member that moves according to each operation mode, a second motor that drives the mode switching member, and the pair of the pair of motors that interlock with the mode switching member. A reel brake for braking the supply / take-up reel base substantially at the same time, and teeth of the pendulum gear and the gear portion of the supply / take-up reel base substantially at the same time as the reel brake is braked in cooperation with the mode switching member. A releasing member for releasing the engagement, and the first motor until at least the engagement between the pendulum gear and the gear portion of the supply / take-up reel base is released when the fast-forward / rewind aspect shifts to the stop aspect. And a control circuit for continuously driving the reel base brake device.