JPH0749634Y2 - Mode changer for tape recorder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a malfunction prevention device in a motor shift mechanism, in which a mechanism is switched to a plurality of operation modes by a cam disk rotated by a motor.

(Prior Art and Problems Thereof) A so-called so-called cam disk conventionally driven by a motor is used, and an operation mode is switched by operating an electromagnet by an electric circuit to control the rotational position of the cam disk. Logic motor shift mechanisms are well known.

This type of mechanism is superior in power consumption and mechanical noise compared to the plunger mechanism that switches the mechanism mode only with the plunger, because the mode switching itself is performed by the power of the motor and only its control is performed by the electromagnet. Since it can be operated by an electric switch, it has excellent operability and is currently the mainstream tape recorder mechanism.

However, control is performed by an electric circuit, but since the actual mechanism mode switching is performed by a cam board, etc.,
For example, if the cam disk for motor switching is released from the lock due to external vibration, etc., or the operating member moves and only the mechanism switches to another mode, the electrical circuit mode and the actual mode may change. This is a major problem of the logic type motor shift mechanism because it has a drawback that the operation mode of the mechanism is different and the operation to switch to the next operation mode is often impossible. It was

(Purpose of the invention) The purpose is to eliminate the above-mentioned drawbacks. In the logic type motor shift mechanism, even if the mechanism malfunctions due to external vibration, the operation mode of the control circuit and the actual mechanism is different. It is an object of the present invention to provide a novel tape recorder mode switching device that does not exist.

(Outline of the device) In a logic type motor shift mechanism in which a mechanism is switched to a plurality of operation modes by a cam disk or the like rotated by a motor and the control is performed by an electromagnet and its control circuit, the mechanism is driven by external vibration or the like. When it malfunctions and enters the switching operation to another mode, it detects this and applies a stop control signal to the control circuit, forcibly sets both the control circuit and mechanism to the stop mode, and the control circuit and the actual It is a novel tape recorder mode switching device which prevents the operation modes of the mechanism from being different from each other.

(Embodiment) FIG. 2 is a plan view of the tape recorder of the present invention, in which 1 is a chassis, 2a and 2b are reel stands, and 3 is a capstan. A flywheel 3a is attached to the capstan 3 so as to rotate integrally therewith, and a pulley 5 and a belt 6 of a motor 4 are attached.
Are linked by.

On the chassis 1 facing the capstan 3, a pinch roller lever 7 having a pinch roller 7a rotatably attached is rotatably arranged by a shaft 8 and is urged by a spring 9 in a direction of being pressed against the capstan 3. ing.

On the chassis 1 between the reel bases 2a and 2b, a head chassis 11 having a magnetic head 10 attached is slidably arranged back and forth by elongated holes 11a to 11c and pins 12a to 12c. It is biased downward as you look. An engaging portion 11d that engages with the pin 7b of the pinch roller lever 7 is formed at the right end of the head chassis, and a protrusion 11e that is constantly engaged with a later-described head chassis controlling rotary lever 13 is formed at a substantially central portion. 11f is cut and raised to the back side of the chassis.

3 to 5 show the structure of the rear surface of the chassis 1,
The rotation lever 13 for moving the head chassis 11 back and forth is the axis
It is rotatably arranged by 14 and the engaging part at one end
13a is always between the projections 11e and 11f of the head chassis 11, and the engagement pin 13b at the other end is always engaged with the cam portion 152 of the cam board 15 described later. By rotating the cam board 15, the head chassis 11 is moved back and forth. Can be controlled.

The cam disk 15 is rotatably arranged on the rear surface of the chassis 1 by a shaft 16, and a gear 151 is formed on the outer periphery of the cam disk 15. The gear 17 is arranged to rotate integrally with the capstan 3, and a large diameter gear 18a, Small diameter gear 18 formed integrally with large diameter gear 18a
Rotation is transmitted via b, a large diameter gear 19a, a small diameter gear 19b formed integrally with the large diameter gear 19a, and a drive gear 20.

On the other hand, on the rear surface of the chassis 1 on the right side of the cam board 15, a trigger lever 21 for controlling the cam board 15 is rotatably arranged by a shaft 22, and one end thereof has cam portions 153, 154 on the upper surface of the cam board 15 which will be described later. An engaging pin 21a for engaging with is formed, and a metal plate 21b is attached to the other end so as to be attracted to an electromagnet 23 attached to the rear surface of the chassis 1, and is always biased clockwise by a spring 24.

The electromagnet 23 is a so-called release electromagnet, and is of a type that includes an iron core of a permanent magnet and that excites the coil to cancel the magnetic force of the permanent magnet. Therefore, for example, as shown in FIG.
When the electromagnet 23 is excited while the metal plate 21b of 21 is attracted to the permanent magnet of the electromagnet 23, the magnetic force of the permanent magnet is offset, and the trigger lever 21 is rotated clockwise by the elasticity of the spring 24.

The cam disk 15 moves the head chassis 11 back to a stop position ST where the magnetic head 10 is separated from the tape T, a reproduction position PL where the magnetic head 10 is pressed against the tape T, and a slight retreat from the reproduction position PL to bring the magnetic head 10 into light contact with the tape T and to speed up Movement control is performed to the music selection position MS where the music can be selected, and the gear 151 on the outer periphery of the gear 151 is formed with toothless portions 151a, 151b, 151c facing the drive gear 20 at each movement position of the head chassis 11. .

On the lower surface of the cam board 15, there is formed a cam portion 152 which is constantly engaged with the pin 13b of the rotating lever 13, and which engages to control the movement of the head chassis 11 to the stop position ST, the reproduction position PL, and the music selection position MS. The surfaces 152a, 152b, 152c are formed continuously.

The engagement surface 152a has the largest diameter, the engagement surface 152b has the smallest diameter, and the engagement surface 152c is formed to have a slightly larger diameter than the engagement surface 152b. Has been decided.

That is, when the pin 13b of the rotating lever 13 is located on the engagement surface 152a having the largest diameter, the rotating lever 13 is in the state of being rotated most clockwise as seen in FIG. 11 is the stop position ST which is the farthest from the tape T.

When the pin 13b of the rotary lever 13 is located on the engagement surface 152b having the smallest diameter, the rotary lever 13 is in the most counterclockwise rotated state as viewed in FIG. Is the reproducing position where the magnetic head 10 is pressed against the tape T.

Further, when the pin 13b of the rotating lever 13 is located on the engaging surface 152c, the rotating lever 13 is at a position rotated slightly clockwise as compared with when the pin 13b is engaged with the engaging surface 152b. The chassis 11 is slightly retracted from the playback position PL and the tape T
So-called high-speed music selection position where the magnetic head 10 is lightly contacted with the
Become MS.

On the upper surface of the cam board 15, cam portions 153 and 154 that engage with the pin 21a of the trigger lever 21 are formed so as to face each other.

The cam portion 154 on the outer side is used for positioning lock of the cam board 15, and is engaged with the pin 21a of the trigger lever 21 to stop, reproduce, and lock projections 154a, 154 for locking at the music selection position.
b, 154c are formed.

The inner cam portion 153 is for controlling the trigger lever 21,
A member for rotating the trigger lever 21 separated from the electromagnet 23 and unlocking the cam board 15 counterclockwise to return to a position where it can be engaged with the locking projections 154a to 154c of the cam portion 154. Mating protrusions 153a to 153c are formed, and further, an engagement slope 153d for converting the pressure contact of the pin 21a of the trigger lever 21 into the starting force of the cam disk 15 is formed.

On the right side of the electromagnet 23, a leaf switch S that detects that the trigger lever 21 has left the electromagnet 23 is arranged. The switch S is normally closed, and is opened when the trigger lever 21 is separated from the electromagnet 23 and rotated clockwise as shown in FIG.

The mechanism portion of the tape recorder of the present invention is constructed as described above, and each operation mode will be described below.

(1) Stopped state As shown in FIG. 3, the cam disk 15 is in a position where its toothless portion 151a faces the drive gear 20, and the locking projection 154a of the cam portion 154 on the upper surface is the pin of the trigger lever 21. The position is held by being locked by 21a. Then, the trigger lever 21 is held by being attracted to the permanent magnet of the electromagnet 23 at its position rotated counterclockwise against the spring 24.

The maximum diameter portion 152a of the cam portion 152 is engaged with the pin 13b of the rotary lever 13 for controlling the head chassis, and the head chassis 11 is retracted by the spring 25 to the stop position ST shown in FIG. .

When the head chassis 11 retracts, the pinch roller lever 7 is pushed down by the engaging portion 11d, and the pinch roller 7d is separated from the capstan 3.

(2) Play state When the electromagnet 23 is instantly excited once in the stop state, the magnetic force of the permanent magnet is canceled for a moment, and the trigger lever 21 is rotated clockwise by the spring 24. As a result, the pin 21a is separated from the locking projection 154a of the cam portion 154, and the locked state of the cam board 15 is released. At the same time, the pin 21a of the trigger lever 21 is pressed against the engaging slope 153d of the inner cam portion 153, and the cam disk 15 receives the rotational starting force in the clockwise direction as shown in FIG. After that, it is rotated by the drive gear 20.

When the cam board 15 rotates clockwise, the pin 13b of the rotary lever 13 gradually moves from the large diameter portion 152a of the cam portion 152 to the small diameter portion 152b.
When the head chassis 11 is moved in the direction of, the head chassis 11 is moved in the direction of advancing upward as viewed in the figure with the engaging portion 13a.

The cam board 15 continues to rotate, and as shown in FIG.
When the pin 13b of 13 moves to the small diameter portion 152b of the cam portion 152,
The head chassis 11 advances to the reproducing position PL in FIG. 2, the magnetic head 10 is pressed against the tape T, and the pinch roller 7a is pressed against the capstan 3 to be in a reproducing state.

On the other hand, the toothed portion 151b faces the drive gear 20, and the rotation transmission to the cam disk 15 is cut off. Also the trigger lever 21
Is rotated counterclockwise when the pin 21a passes through the engaging projection 153a of the cam portion 153, and is again attracted to the electromagnet 23, so that the pin 21a can be engaged with the locking projection of the cam portion 154. Therefore, when the cam board 15 rotates to the above-mentioned position, the cam section
The locking projection 154b of 154 is locked to the pin 21a of the trigger lever 21, and the rotational position of the cam board 15 is locked. The small diameter portion 152b of the cam portion 152, which is in pressure contact with the pin 13b of the rotating lever 13, is a pin.
It is an inclined surface with respect to the pressing direction of 13b, and lever 13
The pressing force of the pin 13b of the above acts as a starting force for rotating the cam disk 15 in the clockwise direction.

(3) Music selection state A music selection state can be obtained by exciting the electromagnet 23 in the above-described reproduction state.

When the electromagnet 23 is momentarily excited in the state shown in FIG. 4, the trigger lever 21 is rotated clockwise by the spring 24, and the engagement pin 21
a is separated from the locking portion 154b of the cam portion 154, and the locked state of the cam board 15 is released.

The cam board 15 is provided with a sloping surface of the small diameter portion 152b of the cam portion 152 and the rotation lever 1
It is rotated clockwise by the pressure contact force of the pin 13b of 3 and comes into mesh with the drive gear 20.

The cam disk 15 is rotated to a position where the toothless portion 151c faces the drive gear 20, and the pin 13b of the rotating lever 13 is a small diameter portion of the cam portion 152.
It moves to the music selection position 152c which is slightly larger in diameter than 152b. At this time, the pin 21a of the trigger lever 21 has the cam portion 153.
By being pressed by b, it rotates counterclockwise and is attracted and held by the electromagnet 23. As shown in FIG. 5, the cam plate 15 has the engagement portion 154c of the cam portion 154 with the trigger lever 154c. The rotational position described above is maintained by being locked to the pin 21a of 21.

As a result, the rotating lever 13 is slightly rotated clockwise, and the head chassis 11 is retracted to the music selection position MS shown in FIG. When the head chassis 11 is retracted, the pinch roller lever 7 is pushed down by the engaging portion 11d, the pinch roller 7a is separated from the capstan 3, and the magnetic head 10 comes into a state of lightly contacting the tape T. By moving a reel base drive system (not shown) at a high speed, it is possible to find the beginning of a piece of music by a known inter-track detection circuit.

In addition, the music selection position 152c of the cam portion 152 is also the pin 1 of the rotation lever 13.
In order to convert the pressure contact force of 3b into the rotational force in the clockwise direction,
An inclination is provided with respect to the pressing direction of 13b.

In the above-mentioned music selection state, when the space between the music on the tape is found or when the music selection operation is stopped, the electromagnet 23
To turn the trigger lever 21 clockwise and
You can unlock 15 locks.

The cam disk 15 is meshed with the gear 20 by the pressure contact force of the pin 13b of the rotating lever 13, and when the toothless portion 151a is rotated to a position facing the gear 20, the cam projection 153c of the cam portion 153 returns to the outside. Pin 21 of the trigger lever 21
The locking projection 154a of the cam portion 154 is locked by a and stops,
Returning to the stopped state in the figure If the electromagnet 23 is excited again (or the electromagnet 23 is kept excited), the reproduction state shown in FIG. 4 can be obtained as described above.

As described above, each time the electromagnet 23 is excited, it is stopped, regenerated,
Since the music selection states can be sequentially set, it is possible to switch between various operation modes by controlling the excitation time or the excitation timing of the electromagnet 23.

The above is the configuration and operation of the mechanism. Next, the control circuit and its malfunction prevention will be described.

As described above, this mechanism rotates the cam disk 15 every time the trigger lever 21 is operated, and switches the operation mode. Therefore, the operation is performed by exciting the electromagnet 23 by an electric circuit.However, if the trigger lever 21 leaves the electromagnet 23 even when the electromagnet is not excited due to external vibration or the like, only the cam board 15 is operated. It rotates and switches to another operation mode, and the mode of the electric circuit that controls the electromagnet 23 to switch the mode differs from the actual operation mode, which interferes with the next operation. The malfunction prevention circuit described below prevents this.

FIG. 1 shows a circuit for controlling the mechanism of the present invention.

26 is a control circuit for controlling the operation mode by exciting the electromagnet 23 according to the operation mode. Stop, playback, music selection mode input terminals P _{1 to} P ₃ (other fast forward, rewind, pause, recording etc. are omitted. the), stop having one end connected to ground, reproduction, music selection switches S ₁ to S ₃ are connected, these switches S ₁
~ S ₃ is closed and a low level pulse is input to its input terminals P _{1 to} P ₃ to control the mechanism in a mode according to the operated switch.

The base of the transistor Q ₂ for driving the electromagnet 23 is connected to the control output terminal OUT of the control circuit 26, and the electromagnet 23 is arranged between the collector of the transistor Q ₂ and the power supply line Vcc. high level signal is output is driven by the transistor Q ₂ is turned from.
Further, D is a backflow prevention diode.

Then, the control circuit 26 rotates the cam board 15 according to the operated mode according to the duration of the high level signal output from the output terminal OUT according to the operation of each operation switch, the interval of the high level signal, that is, the timing, or the like. The position can be controlled.

On the other hand, 27 is a malfunction prevention circuit, a transistor Q ₁ is connected between the stop mode input terminal P ₁ of the control circuit 26 and the ground, and the base of the transistor Q ₁ is via a leaf switch S for detecting the position of the trigger lever 21. It is connected to the power supply line Vcc and also connected to the output terminal OUT of the control circuit 26 via the resistor R.

Therefore, the transistor Q ₁ conducts when its base becomes low level, and when the transistor Q ₁ conducts, the stop mode input terminal P _{1 of the} control circuit 26 falls to the ground, just as when the stop switch S ₁ is operated. It can be in stop mode.

Since the electromagnet 23 is excited only when the trigger lever 21 is operated at the time of switching the operation mode, the control output terminal OUT is normally at the low level regardless of the mode. Therefore, the base of the transistor Q ₁ is connected to the low level via the resistor R, but the switch S 1
Is closed when the trigger lever 21 locks the cam board 15, so that the transistor Q ₁ is held in the off state.

When one of the operation switches is operated in this state and the output terminal OUT becomes high level and the electromagnet 23 operates, the trigger lever 21 rotates to open the switch S, but the transistor Q ₁ has its base. Is kept at a high level by the high level signal of the output terminal OUT and enters, so that there is no conduction and the stop control signal is not applied to the stop input terminal P ₁ .

On the other hand, when the mechanism is in operation, if the trigger lever 21 leaves the electromagnet 23 due to external vibration, etc., the cam board 15 starts rotating and only the mechanism shifts to another operation mode. Although the actual mode of the mechanism differs from that of the control circuit 26, in this case, the electromagnet 23 is not excited and the high level signal is not output from the output terminal OUT of the control circuit 26. Therefore, when the trigger lever 21 is operated and the switch S is opened, the base of the transistor Q ₁ is released from the power supply line Vcc to a low level, and the transistor Q ₁ becomes conductive.

As a result, a low-level pulse is input to the stop mode input terminal P ₁ of the control circuit 26, and the control circuit 26 is set to the stop mode, and the mechanism is also controlled to the stop mode, just as when the stop switch S ₁ is operated. It

By the above operation, even if only the mechanism malfunctions due to vibration or the like even though the control circuit 26 is not operated, the operation modes of the two do not become different and the operation is not substantially disabled. Precise control can be performed.

(Effect of the Invention) As described above, according to the mode switching device of the present invention,
In a logic type motor shift mechanism in which the mechanism can be switched to a plurality of operation modes by a cam disk rotated by a motor, and the control is performed by an electromagnet and its control circuit, a cam disk, etc. due to external vibration, etc. When the lock is released and the mechanism shifts to a switching operation to another operation mode, this is detected and a stop control signal is supplied to the control circuit, and the control circuit and mechanism are forcibly set to the stop mode. Therefore, it is possible to completely prevent an accident in which the mechanism malfunctions due to external vibration, etc., and the next mode switching operation becomes impossible due to the difference between the control circuit mode and the actual mechanism operation mode. It is possible to solve the drawback of the logic type motor shift mechanism which has been a problem.

[Brief description of drawings]

Each drawing shows an embodiment of the present invention. FIG. 1 is a circuit diagram for controlling the mechanism in each operation mode, FIG. 2 is a plan view of a tape recorder, and FIGS. 3 to 5 are mode switching. It is for explaining the structure and operation of the mechanism. Fig. 3 is a stopped state, Fig. 4 is a reproducing state, Fig. 5 is a plan view of the backside of the mechanism showing a music selection state, and Fig. 6 is a starting state of a cam plate. FIG. 7 is a partial plan view showing the above state, and FIG. 7 is a partial plan view for explaining the operation of the position detecting switch of the trigger lever. Explanation of code 3 …… Capstan, 11 …… Head chassis 13 …… Rotating lever, 15 …… Cam board 21 …… Trigger lever, 23 …… Electromagnet 26 …… Control circuit, 27 …… Malfunction prevention circuit S… ... Leaf switch for position detection of trigger lever

Claims (1)

[Scope of utility model registration request] 1. A drive gear rotated by a motor, and a plurality of tooth gaps which are rotated by meshing with the drive gear to set a mechanism in a plurality of modes and hold rotational positions corresponding to the respective operation modes. A cam disk having a portion formed therein, a lock position for locking the cam disk at a rotational position corresponding to each of the above-described operation modes, and a lock release position for releasing the lock and engaging the drive gear. A tape provided with a trigger lever which is controlled by an electromagnet so as to be possible, and a control circuit which controls the electromagnet to operate the trigger lever to control the rotation of the cam board to a rotation position according to each operation mode. In a recorder mode switching device, the trigger lever is unlocked when the electromagnet is in a non-excited state by detecting the operating state of the electromagnet and the moving position of the trigger lever. A malfunction prevention circuit that outputs a stop control signal to the control circuit when the trigger lever moves to the unlocked position while the electromagnet is in a non-excited state. A mode switching device for a tape recorder, characterized in that a stop control signal is supplied to the device to force a stop mode to prevent the rotational position of the cam disk and the operating state of the control circuit from being different. .