JPH01143002A - Device for impressing external magnetic field for magneto-optical disk device - Google Patents

Abstract

PURPOSE:To reduce the size and weight of a magneto-optical disk device by providing a driving shaft which has a 1st cam groove on the outside circumference and a movable cylinder which has a 1st pin engaging with said cam groove on the inside circumference and a 2nd pin engaging with the 2nd cam of a static cylinder on the outside circumference. CONSTITUTION:The movable cylinder 5 is a member driven by the driving shaft 4 and the movement thereof is limited by the static cylinder 6. The movable cylinder 5 is rotationally driven by means of the cam groove 14 and the pin 5a and an electromagnet is horizontally turned via an arm fixed to the movable cylinder 5 and is moved to the prescribed point opposite to the magneto-optical disk when the driving shaft 4 is turned counterclockwise in accordance with the 1st command to move the electromagnet from the initial position to the prescribed point. The movable cylinder 5 descends by gravity when the pin 5b comes to the right end of the horizontal part 16a of the cam groove 16. The electromagnet is moved perpendicularly to the point opposite to the surface of the magneto-optical disk in proximity thereto as the movable cylinder descends.

Description

[Detailed description of the invention] [Industrial application field]

In the present invention, an electromagnet serving as an external magnetic field applying means is moved from near the outer periphery of the magneto-optical disk to a predetermined location close to and facing the surface of the magneto-optical disk based on a command, and is then moved back.
The present invention relates to an external magnetic field applying device in a magneto-optical disk device.

[Conventional technology]

One conventional example will be described with reference to FIGS. 8 and 9. FIG. 8 is a perspective view of essential parts of this conventional example, and FIG. 9 is a side sectional view thereof. In FIGS. 8 and 9, the electromagnet 21 is located in a space other than the space occupied by the cartridge 2 storing the magneto-optical disk 3 when it is inserted or removed, that is, above, and is fixed at a position facing the disk 3 as close as possible. . Note that 4 is an optical head. Another conventional example will be described with reference to FIGS. 10 and 11. FIG. 10 is a perspective view of the main part of this conventional example, and FIG. 11 is a side sectional view thereof. In these figures, an electromagnet 31 is fixed to a rotatable arm 32, and the center of rotation of this arm 32 is is directly connected to the output shaft of the motor 33. Therefore, when inserting or removing the cartridge 2 that stores the magneto-optical disk 3, the arm 32 including the electromagnet 31 is retracted and rotated through the hollow part 2a of the cartridge 2 to the position indicated by the two-dot chain line. It is rotated back to the position and is closely opposed to the surface of the magneto-optical disk 3.

[Problems to be solved by the invention]

As explained above, the conventional example has a very simple structure, but since there is a considerable distance between the electromagnet 21 and the magneto-optical disk 3, the magnetic field strength on the surface of the magneto-optical disk 3 can be controlled at a predetermined level. In order to maintain this value, the electromagnet 21 becomes larger and heavier, and its power consumption also increases. In addition,
The external magnetic field application device and the magneto-optical disk device that stores it also have the disadvantage of being large in size. In another conventional example, the electromagnet 31 can be brought close to the surface of the magneto-optical disk 3 through the hollow part 2a of the cartridge 2, and as a result, the electromagnet 31 can be made smaller and lighter. Furthermore, the mechanism for moving the electromagnet 31 is also simple. However, a large space is required above the cartridge 2 in order to rotate the arm 32 including the electromagnet 31, and the external magnetic field applying device and, by extension, the magneto-optical disk device that houses the same have the disadvantage of being large in size. SUMMARY OF THE INVENTION An object of the present invention is to provide an external magnetic field application device for a magneto-optical disk device that solves the problems of the conventional technology and can be made smaller and lighter.

[Means to solve the problem]

In order to achieve the above object, the external magnetic field applying device in the magneto-optical disk device according to the present invention is such that the electromagnet as the external magnetic field applying means moves from near the outer periphery of the magneto-optical disk as an initial position to close to the surface thereof based on a command. In a device that is moved to a predetermined opposing location and then returned, (a) the device is rotationally driven in one direction around a predetermined axis perpendicular to a plane containing the surface of the magneto-optical disk, and has a first cam groove in an outer peripheral portion; (b) a first cam groove that is rotatable about the predetermined axis and capable of moving straight along the axis, that protrudes from the inner circumferential side and engages the first cam groove;
(c) a movable cylinder having a second cam groove fixed about the predetermined axis as a center line and engaged with the second pin in a peripheral wall; (d) an arm fixed to the movable cylinder so that its axis and longitudinal direction are perpendicular to each other; (e) a mounting frame to which the electromagnet is fixed; (f)
Movement limiting member with respect to this mounting frame □ For example, one end can rotate around another axis parallel to the predetermined axis,
The other end has a link that is rotatable around an axis parallel to one part of the mounting frame and movable along this axis, and a cam groove having a shape corresponding to the predetermined path. The plate member □, which is connected to the mounting frame via this cam groove and the pin that engages with the cam groove, moving the electromagnet along the same plane from near the outer periphery of the magneto-optical disk to an intermediate location;
Next, the drive shaft is moved from this intermediate location parallel to the predetermined axis to a predetermined location that closely opposes the plane of the magneto-optical disk, and rotates the drive shaft in a total of one rotation based on the second command. a control unit that returns the electromagnet from the predetermined location to the initial position via the intermediate location by rotation of the arm, and the arm is directly or indirectly urged to rotate in a direction to assume the initial position; At least one of the movable cylinder and the arm is urged to move straight in a direction in which the electromagnet approaches the surface of the magneto-optical disk, and one part of the mounting frame is perpendicular to the predetermined axis by the movement limiting member. The mounting frame is movable along a predetermined path in a plane and guided so as to be movable in a straight line along the predetermined axis, and the other part of the mounting frame is an end of the arm opposite to the movable cylinder. and are coupled to be rotatable about an axis parallel to the predetermined axis.

[Function] The movable cylinder is a driven member relative to the drive shaft as a driving member, and its movement is limited (restricted) by the stationary cylinder. That is, by the first rotation of the drive shaft based on the first command, the movable cylinder is driven via the first cam groove and the first pin, and the movable cylinder is driven via the second cam groove and the second pin by the stationary cylinder. The shaft rotates in the same direction as the drive shaft, resisting the rotational force in the direction of assuming the initial position. Next, the movable cylinder moves straight along the predetermined axis via the second cam groove and the second pin in accordance with the straight-line bias toward the magneto-optical disk surface. Further, due to the rotation of the latter stage of the drive shaft based on the second command, the movable cylinder moves straight in the opposite direction along the predetermined axis against the latter's straight-forward urging,
Then, in accordance with the rotational bias of the former, it rotates around a predetermined axis in the opposite direction to the previous one and returns to the initial state. On the other hand, the arm fixed to the movable cylinder becomes the driving member,
On the other hand, the mounting frame to which the electromagnet is fixed becomes a driven member, and the movement of the mounting frame is restrained by the movement limiting member, so based on the first command, the electromagnet moves to the magneto-optical disk as the initial position. It moves along the same plane from the vicinity of the outer periphery to an intermediate location based on a combination of rotation and rectilinear motion, and then moves parallel to a predetermined axis at this intermediate location to a predetermined location that closely opposes the plane of the magneto-optical disk. Further, based on the second command, the electromagnet returns to the initial position from the predetermined position via the intermediate position. Embodiment An external magnetic field application device for a magneto-optical disk drive, which shows one embodiment of the present invention, will be described below with reference to the drawings. Fig. 1 is a perspective view of the main parts of this external magnetic field applying device, showing the electromagnet in its initial position, Fig. 2 is a perspective view of the same, showing the electromagnet in an intermediate position, and Fig. 3 shows the electromagnet in its initial position. 7 is a perspective view of the same, showing the electromagnet in its final position, and FIG. 7 is a perspective view of the main components in a disassembled manner. In FIGS. 1 to 3, this external magnetic field applying device consists of a driving part based on a cam mechanism and a driven part based on a link mechanism. First, the driving section will be explained with reference to FIG. 7, and then the driven section and the entire device will be explained with reference to FIGS. 1 to 3. In FIG. 7, reference numeral 4 denotes a drive shaft, the axis of which extends in the vertical direction, has a cam groove 14 as a first cam groove on its outer periphery, and is connected to a motor (not shown). Reference numeral 5 denotes a movable cylinder, and a pin 5a as a first pin is provided on the inner periphery of the cylinder, and a pin 5b as a second pin is provided on the outer periphery at the same location. 6 is a stationary cylinder, and a cam groove 16 as a second cam groove is provided on its peripheral wall. Drive shaft 4. The movable cylinder 5 and the stationary cylinder 6 are coaxial and are provided in contact with the outside in order, and
The contacting members are mutually movable so as to be rotatable about their respective axes and movable linearly in the direction of their axes. Further, the cam groove 14 and the pin 5a are connected to each other, and the pin 5b and the cam groove 16 are connected to each other,
engage with each other. The cam groove 14 includes an upper horizontal portion 14a, a vertical portion 14b, a lower horizontal portion 14c, and an inclined portion 14d, which form a continuous loop. Further, the cam groove 16 includes a horizontal portion 16a and a vertical portion 16b that are joined to each other at right angles. 1 to 3, 7 is an arm, one end of which is fixed to the upper end of the drive shaft 4, and 8 is a mounting frame to which the electromagnet 1 is fixed. 9 is a link, one end of which is provided with a connecting pin 9a, and the other end of which is loosely engaged with a rotating shaft 9b having a fixed axis. Further, the mounting frame 8 is rotatably connected to the arm 7 on the one hand by a connecting pin 7a,
On the other hand, it is rotatably and linearly connected to the link 9 by a connecting pin 9a. The link 9 is urged to rotate counterclockwise around the rotation axis 9b by the spring 11. Note that the arm 7, the mounting frame 8, and the link 9 are each connected to the first. A four-bar link mechanism is configured as the second and third links. Note that the fourth link in this case is a stationary node located between the axis of the drive shaft 4 fixed to the end of the arm 7 and the axis of the rotation shaft 9b. The operation of this device will be explained with reference to FIGS. 1 to 3 and FIG. 7. In FIG. 7, the movable cylinder 5 is a driven member relative to the drive shaft 4 as a driving member, and its movement is limited by the stationary cylinder 6. That is, the first
Command (move the electromagnet from the initial position to the specified location)
By rotating in the direction of the arrow (counterclockwise) at the angle θ of the previous stage based on Rotationally driven. The motion of the movable cylinder 5 is limited by the stationary cylinder 6, but the previous rotation is still caused by the pin 5.
b is allowed to fit through the horizontal portion 16a of the cam groove 16. When the pin 5b comes to the right end of the horizontal portion 16a of the cam groove 16, the movable cylinder 5 descends a certain distance due to its own weight. That is, the pin 5b moves downward along the vertical portion 16b of the cam groove 16, and the pin 5a moves downward along the vertical portion 14b of the cam groove 14. Note that the movable cylinder 5 may be biased by a spring instead of its own weight. After the drive shaft 4 rotates by the angle θ in the first stage, the second stage rotation in the same direction is started based on the second command (to return the electromagnet from a predetermined position to the initial position). Due to this rotation, the movable cylinder 5 remains stationary while the pin 5a engages with the horizontal part 14c of the cam groove 14, but the pin 5a engages with the inclined part 14d and moves upwards relative to the inclined part 14d. Accordingly, the movable cylinder 5 rises against its own weight via the pin 5b and the vertical portion 16b of the cam groove 16. When the pin 5a has gone up the inclined part 14d, the pin 5b reaches the junction between the horizontal part 16a and the vertical part 16b, and then,
The spring 11 (see FIG. 1), which will be described later, returns to the left end of the horizontal portion 16a. That is, the movable cylinder 5 rotates back to the initial position. The drive shaft 4 makes a total of one revolution in the front and rear stages, and the initial position, that is, the pin 5a is in the horizontal part 14a and the vertical part 14 of the cam groove 14.
It returns to the position where it joins b. Now, returning to FIGS. 1 to 3 again, the arm 7 fixed to the movable cylinder 5 becomes a driving member, whereas the mounting frame 8 to which the electromagnet 1 is fixed becomes a driven member. Moreover, the movement of the mounting frame 8 is limited by the link 9 as a movement limiting member. Therefore, based on the first command, the electromagnet 1 is moved near the outer periphery of the magneto-optical disk 3 (first position) as the initial position.
(see figure 2), move along the same plane to just above the hollow part 2a of the cartridge 2 (see figure 2), and then vertically downward at this point. It descends by a certain distance and moves to a location where it closely faces the surface of the magneto-optical disk 3 (see FIG. 3). Also, based on the second command, the electromagnet l moves the magneto-optical disk 3
From the point where it closely faces the surface of
(see figure). Next, an external magnetic field applying device showing another embodiment will be described with reference to FIGS. 4, 5, and 6. FIG. 4 is a perspective view of the main part, showing the electromagnet in the initial position, and FIG. 5 is a perspective view of the same, showing the electromagnet in the intermediate position. FIG. 6 is a perspective view of the same, showing the electromagnet at its final position, and corresponds to FIGS. 1, 2, and 3, respectively, regarding the external magnetic field applying device showing one embodiment. This other device differs from the previous device in the following points. That is, instead of the link 9 in FIG. 1, the cam plate 19 having the cam groove 19a in FIG. Connecting pins 18a that are fixed and slidable following the cam grooves 19a of the cam plate 19 are used, respectively. In this connection, the biasing spring force is a spring 11 acting on the link 9 in the former case, and is a spring 12 acting on the arm 17 in the latter case. In other words, the difference between the above configurations is that the movement limiting member regarding the mounting frame to which the electromagnet is fixed is a link in the former device, and a cam plate with a cam groove in the latter device.

【Effect of the invention】

As explained above, in this invention, the drive shaft,
Due to the rotation of the first stage based on the first command, the movable cylinder is driven via the first cam groove and the first pin, and is limited in movement by the stationary cylinder via the second cam groove and the second pin, The movable cylinder rotates in the same direction as the drive shaft against the rotational bias in the direction of taking the initial position, and then the movable cylinder rotates between the second cam groove and the second cam groove.
The movable cylinder is moved along the predetermined axis against the linear force by the subsequent rotation based on the second command of the linear force drive shaft which approaches the surface of the magneto-optical disk through the pin. It moves straight in the opposite direction, and then rotates around a predetermined axis in the opposite direction according to the rotational force to return to its initial state; on the other hand, the arm fixed to the movable cylinder becomes a driving member, and The mounting frame to which the electromagnet is fixed becomes a driven member, and the movement of the mounting frame is restrained by a movement limiting member. Based on the first command, the electromagnet moves from the initial position near the outer periphery of the magneto-optical disk. The disk moves along the same plane to an intermediate point based on a combination of rotation and rectilinear movement, and then moves parallel to a predetermined axis at this intermediate point to a predetermined location that closely opposes the plane of the magneto-optical disk; Based on this, the electromagnet returns from the predetermined position to the initial position via an intermediate position. Therefore, the present invention has the following superior effects compared to the conventional technology. (1) Since the electromagnet can be placed close to the surface of the magneto-optical disk, it can be made smaller and consume less power. (2) As with the previous item, since the space in which the electromagnet moves is small, the external magnetic field application device and, by extension, the magneto-optical disk device that houses it can be downsized. (3) Since it is based on a cam mechanism and a link mechanism, the structure is simple. (4) Since the operation is performed by one rotation of the drive shaft in one direction, the power source does not need to be a single one, and moreover, it is of the unidirectional rotation type, and as with the previous item, reliability can be improved and costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the main parts of an embodiment of the present invention, showing the electromagnet at its initial position, and FIG. 2 is a perspective view of the same, showing the electromagnet at an intermediate position. Figure 3 is a perspective view of the same, showing the electromagnet in its final position, Figure 4 is a perspective view of the main parts of another embodiment, showing the electromagnet in its initial position, and Figure 5 is the same. FIG. 6 is a perspective view showing the electromagnet in the intermediate position; FIG. 6 is a perspective view thereof showing the electromagnet in the final position; FIG. 7 is common to one embodiment and another embodiment. Figure 8 is a perspective view of the main parts of one conventional example, Figure 9 is a side sectional view thereof, Figure 10 is a perspective view of the main parts of another conventional example, and Figure 10 is a perspective view of the main parts of another conventional example. FIG. 11 is a side sectional view of the same. Description of symbols 1: Electromagnet, 2: Cartridge, 2a: Hollow part, 3: Magneto-optical disk, 4: Drive shaft, 5: Movable cylinder, 5a: First pin, 5b = Second pin, 6: Stationary cylinder, 7. 17:
Arm, 7a, 9a, 18a: Connection pin, 8.18
: Mounting frame, 9; Link, 9b : Rotation axis, 11.12
: Spring, 14.16.19a : Cam groove, Kabuto Figure 7 Figure 8 Figure 9

Claims (1)

[Scope of Claims] 1) An apparatus in which an electromagnet serving as an external magnetic field applying means is moved based on a command from an initial position near the outer periphery of the magneto-optical disk to a predetermined position close to and opposite to the surface of the disk, and then moved back, (a) The magneto-optical disk is rotated in one direction around a predetermined axis perpendicular to a plane including the surface thereof, and a first
(b) a drive shaft that is rotatable around the predetermined axis and can move straight along the axis, and that protrudes from the inner circumferential side and engages with the first cam groove; (c) a movable cylinder having a first pin and a second pin protruding from the outer circumferential side; (d) an arm fixed to the movable cylinder with its longitudinal direction perpendicular to its axis; (e) a mounting frame to which the electromagnet is fixed; (f) movement relative to the mounting frame; a limiting member; (g) a first
The electromagnet is moved along the same plane from near the outer periphery of the magneto-optical disk to an intermediate position by a previous rotation of less than one rotation of the drive shaft based on a command, and then from this intermediate position parallel to the predetermined axis. to a predetermined location that closely opposes the magneto-optical disk plane, and rotates the front stage of the drive shaft based on a second command, and rotates the drive shaft for a total of 1
and a control unit that returns the electromagnet from the predetermined location to the initial position via the intermediate location by a subsequent rotation, and the arm is directly or indirectly rotated in a direction to assume the initial position. Further, at least one of the movable cylinder and the arm is urged to move straight in a direction in which the electromagnet approaches the surface of the magneto-optical disk, and one part of the mounting frame is The mounting frame is movable along a predetermined path in a plane perpendicular to a predetermined axis and is guided so as to be movable straight along the predetermined axis, and the other part of the mounting frame is opposite to the movable cylinder of the arm. An external magnetic field applying device in a magneto-optical disk device, characterized in that the external magnetic field applying device is connected to a side end portion thereof so as to be rotatable around an axis parallel to the predetermined axis. 2) In the device according to claim 1, one end of the movement limiting member is rotatable around a fixed axis parallel to the predetermined axis, and the other end is rotatable around a fixed axis parallel to the predetermined axis. An external magnetic field applying device in a magneto-optical disk drive, characterized in that the link is rotatable around an axis parallel to the predetermined axis and is connected to allow straight movement along the axis. 3) In the device according to claim 1, the movement limiting member includes a cam groove having a shape corresponding to the predetermined path;
An external magnetic field application device for a magneto-optical disk device, characterized in that it is a plate-like member connected to a mounting frame via the cam groove and a pin that engages with the cam groove.