JPH0159658B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drive mechanism for a reel stand in a tape recorder, video tape recorder, etc.

As a conventional reel stand drive mechanism for tape recorders, video tape recorders, etc., (1) the reel stand is driven to rotate by the rotational force of a constant speed rotating part such as a capstan, and the reel stand is driven by the constant speed rotating part and the reel stand. (2) A mechanical torque limiter using a felt, etc. using a dedicated reel motor, or a rotation speed dependent method using eddy current. (3) There are those that use a type limiter, and (3) those that use a dedicated reel motor and drive the reel stand while controlling the voltage of the reel motor without using a torque limiter.

However, according to the above method (1), at least two stages of transmission torque are required depending on the tape running mode, so it is necessary to turn the limiter on and off or switch the limiter torque, and the idler transmission mechanism and lever mechanism etc., and has many problems such as restrictions on mechanism layout, reliability of operation, and difficulty in adjusting switching timing. Also, according to (2) above, in the case of a mechanical limiter, the above (1) applies.
However, limiters using eddy currents have a simpler mechanism, but there is a limit to the amount of torque that can be transmitted. In addition, according to item (3) above, although the mechanism is simple, the torque of the motor fluctuates instantaneously, resulting in uneven rotation (wow, etc.).
The problem is that it tends to cause flutter.

The purpose of the present invention is to eliminate the need for a complicated mechanism and to arbitrarily switch the torque limiter using only an electric signal, and to obtain stable transmission torque in any tape running mode so that uneven rotation is less likely to occur. The object of the present invention is to provide a reel stand driving device that has the following features.

The present invention will be explained below with reference to illustrated embodiments.

In FIG. 1, a rubber ring 4 fitted onto the circumferential surface of an idler 3 is brought into pressure contact with a motor pulley 2 of a reversible reel motor 1. idler 3
As shown in FIG. 2, the idler shaft 6 is rotatably and loosely fitted to the idler shaft 6 which is fixed to the idler lever 5. The idler lever 5 is the chassis 7
At the top, the idler lever 5 can move freely in one plane within the range of the window hole 7a formed in the chassis 7, and the idler lever 5 is moved downward in FIG. By being biased, the rubber ring 4 on the peripheral surface of the idler 3 comes into pressure contact with the motor pulley 2 as described above. An idler 9 is also rotatably fitted on the shaft 6 between the idler 3 and the idler lever 5. A rubber ring 10 is integrally fitted on the peripheral surface of the idler 9. idler 3
There is a friction material 1 such as felt between the and idler 9.
1 is interposed between the idler 9 and the idler lever 5, and a friction material 12 such as felt is also interposed between the idler 9 and the idler lever 5. The idler 3 is pressed downward in FIG. 2 by the coiled repulsion spring 13, and as a result, appropriate frictional forces are generated between the idler 3 and the idler 9 and between the idler 9 and the idler lever 5. There is. Therefore, when the idler 3 is rotationally driven in the clockwise direction in FIG. 1 by the motor 1 via the motor pulley 2, the idler 9 is rotationally driven in the clockwise direction due to the frictional force between the idler 3 and the idler 9. Due to the frictional force between the idler 9 and the idler lever 5, the idler lever 5 is moved to the right in FIG. The reel stand 14 is adapted to be rotated counterclockwise in FIG. Conversely, when the idler 3 is rotated counterclockwise in FIG. 1, the idler lever 5 is moved to the left in the same figure, and the ring 1 of the idler 9
0 presses against the reel stand 15 on the left side and the reel stand 15
is designed to be rotated clockwise.
The details of the mechanism in which the idler lever 5 is moved by frictional force are disclosed in the Utility Application filed in 1982 by the applicant.
It is described in the specification and drawings of No. 112380.

As shown in FIG. 3, three arcuate slots 3a are formed on the same circumference on the back surface (lower surface in FIG. 2) of the idler 3, as shown in FIG. Further, on the back side of the other idler 9, a recessed part 9a is formed as shown in FIG. 4, and three holes 9b are formed in the recessed part 9a at equal intervals on the same circumference. is formed. A ring-shaped stopper 16 as shown in FIG. 5 is loosely fitted into the recessed portion 9a of the idler 9. As shown in FIG. Three protrusions 16a are formed on the upper surface of the stopper 16, and these protrusions 16a fit into the three holes 9 of the idler 9.
It is loosely fitted in b. A ring-shaped permanent magnet 17 magnetized in the thickness direction is provided on the bottom side of the stopper 16.
are fitted and fixed together. Idler lever 5
An electromagnet 18 is fitted and fixed on the upper surface of the magnet 18 at a position facing the permanent magnet 17. When the electromagnet 18 is excited, a repulsive force is generated between it and the permanent magnet 17, so that the stopper 16 moves upward in FIG. 2, and the protrusion 16a of the stopper 16 enters the slot 3a of the idler 3. . An attraction plate 19 made of a magnetic material is fixed to the bottom side of the idler lever 5, and by generating a weak attraction force between the permanent magnet 17 and the attraction plate 19, the electromagnet 18 is in a demagnetized state. At this time, the magnet 17 and the stopper 16 integrated therewith can be reliably maintained at the initial position.

Next, the operation of the above embodiment will be explained. First, when recording and playing (hereinafter referred to as "PLAY") while transporting the tape at a constant speed, the electromagnet 18
The reel motor 1 is driven to rotate in a demagnetized state. When the electromagnet 18 is in a demagnetized state, as shown in the left half of FIG.
has come out of the slot 3a of the idler 3. Therefore, when the motor pulley 2 is rotationally driven in this state, the rotational force of the pulley 2 is transmitted to the reel stand 14 or the reel stand via the idler 3 integrated with the rubber ring 4, the friction plate 11, and the rubber ring 10 of the idler 9. 15, and the tape is wound onto a tape reel (not shown). While the tape is transported at a constant speed, the reel stand 14 or the reel stand 15
The rotational speed of the friction plate 1 will vary depending on the thickness of the tape, but the difference in rotational speed during this period is due to the friction plate 1
absorbed by a slip mechanism including 1, and
Through the intervention of the slip mechanism, the reel stand 14 or the reel stand 15 is rotationally driven by an appropriate torque.

Next, fast forward the tape (hereinafter referred to as "FF")
Alternatively, when performing early rewinding (hereinafter referred to as "REW"), the motor 1 is driven to rotate while the electromagnet 18 is energized. When the electromagnet 18 is energized, the second
As shown in the right half of the figure, the stopper 16
rises and its protrusion 16a is inserted into the slot 3 of the idler 3.
Enter a. Therefore, when the motor 1 is rotationally driven in this state, the idler 3 is rotationally driven via the motor pulley 2, and the rotational force of the idler 3 is applied to the stopper 16 by the wall surface of one end of the slot 3a. The rotational force of the stopper 16 is transmitted to the protrusion 16a, and the rotational force of the stopper 16 is transmitted to the idler 9 by the wall surface of one end of the hole 9b of the idler 9, and the rotational force of the idler 9 is transmitted to the reel stand 14 or the reel stand 15. is transmitted to. Therefore, the friction material 11
The slip mechanism including the idler 3 and idler 9 does not operate effectively, and the result is substantially the same as if the idler 3 and idler 9 were directly connected. will be carried out.

In addition, by demagnetizing the electromagnet from the FF and REW states,
When attempting to enter the PLAY state, it is conceivable that the stopper 16 may not descend smoothly due to mutual pressure contact between the protrusion 16a of the stopper 16 and the wall surface of one end of the slot 3a of the idler 3. Therefore, FF,
When changing from REW to PLAY, the motor 1 is temporarily reversed, the idler 9 is applied to the reel stand on the opposite side, and the impact is used to excite the electromagnet 18 in the opposite direction. A suction force is applied between them to forcefully separate the stopper 16 from the idler 3. In this case, a brake is applied to the reel stand to prevent it from rotating due to impact. As the brake mechanism of the reel stand, an electromagnetic brake as described in the specification and drawings of the above-mentioned Japanese Utility Model Application No. 112380/1980 can be used.

The control system for the electromagnet 18, reel motor 1, and electromagnetic brake described above is as shown in FIG. In FIG. 6, each mode signal of PLAY, FF, REW, and STOP selected by the operating means 21 is inputted to the control circuit 22, and the control circuit 22 stores the mode signal in the mode storage section 23 and The reel stand electromagnetic brake drive circuit 24, the idler electromagnetic clutch drive circuit 25, and the reel motor drive circuit 26 are controlled by the mode signal from the operating means 21 and the storage signal from the mode storage section 23, respectively. There is. The idler electromagnetic clutch drive circuit 25 is used to excite and demagnetize the electromagnet 18 described above, and the reel motor drive circuit 26 is used to perform high-speed rotation, low-speed rotation, and stopping of the reel motor 1 described above. be. Each of these drive circuits is controlled by the control circuit 22 at the timing shown in FIG. In FIG. 7, the limiter is a torque limiter consisting of a slip mechanism including the friction material 11, and limiter ON means that the limiter, that is, the slip mechanism is operating effectively.
OFF means that the limiter is ignored and the idler 3 and idler 9 are directly connected. Now, for example, when switching from FF to PLAY, referring to Fig. 7, immediately after the power supply to the reel motor is stopped, power is temporarily supplied in the reverse direction, and the idler 9 is applied to the reel stand on the opposite side. give a shock. On the other hand, an electromagnetic brake is applied to the take-up reel stand and the supply reel stand, but in this case, since the inertia of the supply reel stand is large, the brake is applied at a high voltage to generate a large braking force on the supply reel stand. Further, a reverse voltage is applied to the electromagnetic clutch to ensure that the clutch is released and the slip mechanism can operate effectively. After this temporary operation is completed, the electromagnetic clutch and the brakes of both reel stands are turned off, and a relatively low voltage is supplied to the reel motor to rotate the reel motor at a relatively low speed, thereby rotating the tape at a constant speed. Transport and perform PLAY operation. REW
When switching from FF to PLAY, from FF or REW
The same control is applied when switching to STOP. Also,
When switching from PLAY to FF or REW, first apply high voltage to the electromagnetic clutch to ensure clutch operation, then apply low voltage to maintain clutch operation. apply the brakes. On the other hand, after the reel motor is once stopped, a high voltage in a predetermined direction is applied to drive it to rotate at high speed, and then FF and REW operations are performed.

According to the present invention, since the torque limiter can be arbitrarily switched using only an electric signal, a complicated mechanism is not required, space can be saved, and operation reliability can be improved. Furthermore, the mode setting can be completely switched electrically, and the mechanism can be simplified from this point of view. The fact that pure electrical mode switching is possible means that the timing of the operation of each part can be set freely and accurately, and reliable operation can be performed. Further, in a fixed operation mode, there is no torque fluctuation and stable torque is obtained, so that stable tape transportation without rotational unevenness can be performed. Furthermore, the electromagnetic clutch does not connect the first idler and the second idler simply by energizing and de-energizing the electromagnet, but rather uses a stopper to connect the first idler and the second idler. A permanent magnet is provided along with an electromagnet facing it, and the attraction and repulsion between the permanent magnet and the electromagnet is used to connect the first idler and the second idler, ensuring reliable and quick disconnection. be able to.

In the illustrated embodiment, the electromagnetic clutch mechanism is of a movable magnet type, but it may be of a movable coil type with the magnet fixed.
Further, the suction piece 19 of the stopper 16 when the electromagnetic clutch is not energized does not necessarily need to be provided when the chassis 7 or the idler lever 5 is made of a magnetic material. Additionally, in the illustrated embodiment, the first
A reel stand driving device comprising an idler, a second idler, an electromagnetic clutch, etc. is provided on an axis different from the axis of the reel stand and on the side of the reel stand. The drive device may be incorporated coaxially with the reel stand.

[Brief explanation of drawings]

Fig. 1 is an external plan view showing an embodiment of the present invention, Fig. 2 is a vertical sectional view of the main part of the same embodiment, Fig. 3 is a rear view of the first rotating body in the above embodiment, and Fig. 4. 5 is a plan view of the stopper in the above embodiment, FIG. 6 is a block diagram showing an example of a control system used in the present invention, and FIG.
The figure is a timing chart showing the operation of the control system. DESCRIPTION OF SYMBOLS 1... Reel motor, 2... Motor reel (driving rotating body), 3... First idler, 5... Idler lever, 6... Idler shaft, 9... Second idler, 11... Slip mechanism 14, 15... Reel stand, 16... Stopper, 17... Permanent magnet, 18... Electromagnet forming the electromagnetic clutch mechanism.

Claims (1)

[Claims] 1. A drive rotary body rotationally driven by a motor, a reel stand for winding the tape, and a transmission means for transmitting the rotational force of the drive rotor to the reel stand. , the transmission means includes a first idler that is rotationally driven by the driving rotary body, and a second idler that is provided coaxially with the first idler and that transmits rotational force to the reel stand. , a slip mechanism for transmitting the rotational motion of the first idler to the second idler with a predetermined torque, an idler lever that supports the second idler via a friction material, and a permanent magnet at one end. A stopper having a protrusion at the other end is disposed in the concave portion of the second idler, an electromagnet is provided on the idler lever so as to face the permanent magnet, and by switching the energization to the electromagnet, the protrusion is moved to the first position. 1. A reel stand drive mechanism comprising an electromagnetic clutch mechanism that can be fitted into a hole formed in an idler and allows a first idler and a second idler to rotate together.