JPS6130336B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electromagnetic actuating device for a tape recorder, and more specifically, it is an object of the present invention to stably electromagnetically control an actuating device for pressing a pinch roller against a capstan using a motor as a drive source in an energy-saving manner. This is the first purpose. A second object of the present invention is to provide a function for bringing the above-mentioned actuating device into a reset state, i.e., an auto-shut-off function, when the power to the device is cut off or when it becomes substantially impossible to maintain a predetermined voltage level. The goal is to provide this with a simple configuration.

In such a conventional electromagnetic actuating device, a notched gear is activated by electromagnetic force and engaged with a pinion driven by a motor to produce an intermittent output to press the pinch roller.
However, in the specific configuration of this conventional method, if the notch gear is configured to be activated with a light load, a problem arises in that the activation device is inadvertently activated due to slight vibrations. That is, one of the problems with the conventional system is that it is not possible to simultaneously increase the reliability of the starting device and reduce electromagnetic energy.

On the other hand, in order to prevent unnecessary deformation of the pinch roller, the pinch roller is automatically pressed when the power to the tape recorder is cut off, or when the power supply voltage drops below a predetermined level and the tape can no longer be driven. It will be necessary to cancel it. However, in the conventional method described above, a complicated device configuration is usually required to enable this release operation. In other words, another problem with the conventional method is that based on this complicated device configuration,
This impeded the simplification and reliability of the device.

The present invention has been made to solve the above-mentioned problems, and utilizes the power of a motor to selectively operate the above-mentioned starting device. In other words, a configuration is adopted in which power is obtained from the motor to bring the starter into the non-operating state, and the shift to the non-operating state is prevented by selectively activated electromagnetic means, and the pinch roller is pressed and released. It is designed to tighten. An embodiment of the present invention will be described below.

In FIG. 1, a triangular cam 12 having a maximum radius portion 12a and a minimum radius portion 12b is rotatably provided with respect to a shaft 10 that is installed on a device board (hereinafter referred to as the board) (not shown). The cam follower 14, the output rack 16, and the differential rod 18 are connected to the board by a mechanism (not shown) at arrows 20 and 22.
It is supported so that it can move freely in the direction. The cam follower 14 is formed with a square hole including flat parts 14a and 14b that come into contact with the triangular cam 12, and a rack part 14c is formed at the end. A pinion 26 is rotatably supported by a shaft 24 mounted on the differential rod 18, and this pinion 26 meshes with the above-mentioned rack portion 14c and output rack 16. The activation lever 28, which is made of soft iron, is rotatably supported by a shaft 30 mounted on a base plate, and biased clockwise by a spring 32 stretched between one end of the shaft 30 and the base plate.

Cam portions 18a and 28a are formed at a portion of the differential rod 18 and at the tip of the activation lever 28, respectively. A spring 34 is stretched between the hook provided on the output rack 16 and the board, and energizingly holds the output rack 16 in the position shown in the figure where it abuts against a stopper 36 erected on the board. stoppa 38
The differential rod 18 is also erected on the base plate and is located close to the upper end of the differential rod 18 determined by the position of the cam 12 and output rack 16 in the figure. An electromagnetic coil 42 that terminates at terminals 42a and 42b is wound around the magnetic core 40, and flat portions 40a and 40b are formed at the tips. These flat parts 40a and 4ab are adapted to abut and engage with a flat part 28b provided at one end of the activation lever 28, so that the lever 28
When in this contact state due to the action of
The magnetic core 40 is fixed to the substrate so that 8a and 28a are on the verge of engagement.

The output shaft 44a of the motor 44, which can be freely reversed, has
A pair of one-way clutches 46, 4 that use this output shaft as an input to generate one-way rotational outputs in opposite directions.
8 is provided, and when the motor rotates in the direction of arrow 50, the clutch 46 produces a rotational output in the direction of arrow 54. Further, when the motor rotates in the direction of arrow 52, clutch 48 generates a rotational output in the direction of arrow 56. A tape drive element 60 including a capstan 58, which is a rotating body for driving the magnetic tape, an idler, etc., is connected to the clutch 48. Further, the output of the clutch 46 is transmitted to the triangular cam 12 via a reduction gear 61.
The rotational position of the triangular cam 12 is determined by the cam detection switch 62.
The switch 62 detects the position of the cam 12 as shown in the figure and the position rotated by 180 degrees from the position shown in the figure (see FIG. 2), and sends detection outputs to the control circuit 64. The control circuit 64 is supplied with electrons by a power source 66 and controls energization of the motor 44 and electromagnetic coil 42 based on commands from the operation button 68 and switch 62. This control will be described later.

On the other hand, a pinch roller lever 72 is connected to the output rack 16 via a spring device 70. This lever 72 is rotatably supported by a shaft 74 mounted on the base plate, and a pinch roller 78 is rotatably supported by a shaft 76 mounted on the lever 72. The above-described spring device 70 is for pressing the pinch roller 78 against the capstan 58 to drive the magnetic tape 80 when the output rack 16 is displaced from the position shown in the figure in the direction of arrow 20. Even if it is displaced further in the direction of arrow 20, it is provided in order to absorb this displacement and stabilize the above-mentioned pressure welding. Note that the operation button 68 has
A tape recorder is equipped with buttons for playback, stop, fast forward, rewind, etc., which are required for tape recorders, but operations other than playback and stop are not covered by this example. The related explanation will be omitted. Furthermore, the structure for bringing the tape 80 into fast forward and rewind states is also omitted because it has the same meaning.

Next, the operation of this device will be explained. When the regeneration operation is selected by the operation button 68 in FIG. 1, the control circuit 64 energizes the coil 42 and also energizes the motor 44 to rotate in the direction of arrow 50. As a result, the cam 12 starts rotating and drives the cam follower 14 in the direction of arrow 22. On the other hand, since the output rack 16 is energized by the spring 34, the differential rod 18 attempts to displace in the direction of arrow 22 in accordance with the movement of the cam follower 14, but this displacement is caused by the activation of the magnetic core 40. It is regulated by the tip 28a of the lever 28. Therefore, the movement of the cam follower 14 is transmitted to the output rack 16 via the rack portion 14c and the pinion 26, causing it to be displaced in the direction of arrow 20. When the cam 12 rotates further and reaches the position shown in FIG.
2 is activated, and the control circuit 64 moves the motor 44 to the direction indicated by the arrow 5.
Starts the operation of energizing in two directions. In this state, the output rack 16 has been raised to the position shown in FIG. 2, pressing the pinch roller 78 against the capstan 58 via the spring device 70. Therefore, in response to the operation of the motor starting to rotate in the direction of arrow 52, the tape drive element 60 is driven and the tape 80 starts running by the capstan 58. Note that the details of the means for winding up the tape sent out by the capstan 58 will be omitted.

Next, when a stop operation is selected using the operation button 68 from the reproducing state shown in FIG. 2, the control circuit 64 switches the energization so that the motor rotates in the direction of arrow 50 again. Therefore, the cam follower 14 is driven in the direction of the arrow 20, and the output rack 16 is driven in the direction of the arrow 20 from FIG.
The displacement in the direction opposite to that shown in the figure begins. During this time, the electromagnetic coil 42 remains energized. The output rack 16 and cam 12 are moved from the position shown in FIG.
When the switch 62 returns to the position shown in the figure, the switch 62 is activated and the control circuit cuts off the power to the motor 44 and the electromagnetic coil 42. That is, the device returns to the stopped state shown in FIG.

Note that the pinch roller 78 returns from the position shown in FIG. 1 to the position shown in FIG. 2 and from the position shown in FIG. 2 to the position shown in FIG. It should be noted that no sound is generated, and even if the pinch roller 78 or the spring device 70 does not operate as desired for some reason, the stopper 38 prevents the differential rod 18 from moving in the direction of arrow 20. It should be noted that since the output rack 16 is regulated, the output rack 16 is forcibly driven in the direction of the arrow 22, and the transition from FIG. 2 to FIG. 1 is performed stably.

FIG. 3 shows a mode in which no playback operation is activated. The operation of disabling the pinch roller 78 when an operation other than a play operation or a stop operation is performed using the operation button 68 shown in FIG. 1 (for example, a fast forward operation) will be explained with reference to this figure. In this case as well, the motor 4 shown in FIG.
4 is energized to rotate the cam 12, but the difference from the explanation given in FIG. 1 is that the electromagnetic coil 42 is not energized. Therefore, due to the rotation of the cam 12, the cam follower 14 moves toward the arrow 22.
When the differential rod 1 is displaced in this direction, the differential rod 1
8 also tries to be displaced in the same direction. At this time, the cam portion 18a of the differential rod 18 comes into contact with the cam portion 28a of the activation lever 28, generating a biasing force that causes the activation lever 28 to rotate counterclockwise around the shaft 30.

On the other hand, the activation lever 28 is biased clockwise by a spring 32, and the output rack 16 is also biased by a spring 34. Now, the shapes of the cam portions 18a and 28a described above are determined as follows based on the relationship of the forces described above.
That is, if the differential rod 18 receives a downward force when the attraction force generated by the electromagnetic coil 42 is not acting on the activation lever 28, the differential rod 18 will move against the biasing force of the spring 32. Rotate the activation lever 28 counterclockwise. In other words, spring 34
is set to generate the additional force necessary to apply this force to the differential rod 18. In comparison, the biasing force generated by the spring 32 is set to be extremely small, and it is sufficient to simply rotate the activation lever 28 clockwise and generate a force to return it to the state shown in FIG. 1. As a result of setting such a force relationship, even if the cam 12 is displaced from the position shown in FIG. 1 to the position shown in FIG. 3, this displacement will be absorbed by the displacement of the differential rod 18, and the output rod 16 will not be displaced at all. Therefore, the pinch roller 78 is not displaced and remains in a stopped state. A detailed explanation of the operations performed by the tape recorder in this mode in which the reproduction operation is not started and explanation of its configuration will be omitted, but examples include fast forwarding and rewinding operations.

The operation of the auto-shutoff function will be explained with reference to FIG. When the power supply from the power supply 66 is cut off in the reproducing state shown in FIG. 2, the apparatus operates as follows. Incidentally, the power source 66 may be a commercial power source, for example, or may be a battery. In the former case, the power supply is cut off due to a power outage or a timer operation, and in the latter case, the battery electromotive force is outside a predetermined value, and the power supply is cut off. Now, if the power supply is cut off in the state shown in FIG. 2, the control circuit 64 can no longer maintain the energization of the electromagnetic coil 42, and therefore the electromagnetic attraction is used to hold the activation lever 28 in the position shown in the diagram. Power disappears. Therefore, the force relationship in this state is the same as that explained in FIG.
a acts on the cam portion 28a of the activation lever 28 to rotate it counterclockwise about the shaft 30. Therefore, there is nothing in the differential rod 18 that restricts its displacement in the direction of arrow 22, and the differential rod 18 can be freely displaced in this direction. At the same time, the output rack 16 is also free to displace in the same direction and is displaced based on the biasing force of the spring 34. These operations occur simultaneously, and the differential rod 18 and output rack 16 are displaced from the position shown in FIG. 2 to the position shown in FIG. be done.

The above is a description of the specific configuration and operation of this embodiment, and here, its characteristic points will be listed.

First, the characteristics of the operation of pressing the pinch roller 78 will be explained. As explained in FIG. 3, the mode in which the device for pressing the pinch roller 78 is brought into a non-operating state is configured to be carried out using the power of the motor as the power source. Further, the mode in which the pinch roller 78 is pressed into contact with the pinch roller 78 is configured to be activated by simply holding the starting lever 28 electromagnetically in the state shown in FIG. 1 so as not to shift to the mode shown in FIG. 3. Flat portion 28 of activation lever 28 in FIG.
b is in contact with the flat parts 40a and 40b of the magnetic core 40, forming a so-called magnetically closed loop. As is well known, the magnetic attraction force in this state is extremely large, and therefore the electromagnetic coil 42
This state can be maintained with only a very small amount of energization. Furthermore, it should be easy to understand that there is no fear that this device will malfunction due to vibration or the like.

Next, the features of the configuration for automatically shutting off the pinch roller 78 will be explained. As is clear from the content explained in FIG. 4, the feature is that there is no mechanism specifically provided to realize automatic shut-off. That is, the feature of the operation of pressing the pinch roller 78 is that it can directly provide an auto-shutoff function. Therefore, the feature is that this function is realized with a simple configuration.

As described above, the electromagnetic actuating device for a tape recorder of the present invention includes a cam driven by a motor, a cam follower that follows the cam, and an output member that displaces the pinch roller in conjunction with each other. By providing a differential member that differentially displaces with respect to the cam follower and the output member, and regulating the displacement of the differential member by electromagnetic force,
The cam follower and the output member work together to press the pinch roller against the capstan. The configuration for regulating the displacement of the differential member is a combination of a starting member that can freely lock the differential member and an electromagnetic device that attracts and holds the starting member at the locking position. . As is well known, electromagnetic force generates its maximum force in an adsorbed state.
As described above, the electromagnetic energy required for simply attracting and holding the activation member can be extremely small. In addition, the action of releasing the pinch roller that is in pressure contact with the capstan is performed by the action of a cam provided on at least one of the differential member or the starting member, and as the electromagnetic force disappears, the starting member is differentially moved. Since this is done automatically by displacing the member to an unrestricted position, this is possible with a simple configuration.
Therefore, by employing the present invention, it is possible to improve the reliability and energy saving of such a device, and it is also possible to provide a so-called auto-shut-off function at a low cost.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing the stopped state of the device in the embodiment of the present invention, Fig. 2 is a plan view showing the reproducing state, Fig. 3 is a plan view showing the state in which the reproducing operation is not started, and Fig. 4 is a plan view showing the device in a pinch state. FIG. 3 is a plan view showing a state in which the rollers are brought into an auto-shut-off state. 12...triangular cam, 14...cam follower, 1
6... Output rack (output member), 18... Differential rod (differential member), 18a... Cam portion, 26...
Pinion, 28... Starting lever (starting member), 2
8a...cam part, 32...spring (second spring),
34... Spring (first spring), 40... Magnetic core (electromagnetic device), 42... Electromagnetic coil (electromagnetic device),
44...Motor, 58...Capstan, 78...
...pinch roller, 80...magnetic tape.

Claims (1)

[Claims] 1. A magnetic tape drive capstan, a cam that is driven and rotated by a motor, a cam follower that is interlocked with the cam, an output member that is movable between a return position and an actuated position, and an output member that is interlocked with the output member and that is At the return position, separate from the above capstan,
a pinch roller that presses against the capstan at the operating position of the output member; a first spring that biases the output member from the operating position toward the return position;
A differential member that interlocks with the cam follower and the output member in a differential relationship through a differential gear mechanism, and a first position where the differential member is locked and a second position where the differential member is not locked. It includes a movable starting member, a second spring that urges the starting member from the second position to the first position, and an electromagnetic device that attracts and holds the starting member at the first position. , at least one of the differential member and the starting member includes a cam portion that displaces the starting member from the first position to the second position by displacement of the differential member, and the operating state of the electromagnetic device When the starting member locks the differential member, the output member is displaced in conjunction with the cam follower to press the pinch roller against the capstan, and when the electromagnetic device is in an inactive state, Since the differential member can displace the activation member from the first position to the second position via the cam portion, the output member returns to the return position due to the biasing force of the first spring. An electromagnetic actuating device for a tape recorder, characterized in that the pinch roller is stopped at a position separated from the capstan.