JPS593746A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To perform secure recording and reproduction, by moving up and down a pad arm which presses a vertically movable magnetic disk automatically associatively with only the loading and unloading of a cassette, and pressing the disk against a head. CONSTITUTION:The pad arm 70 has a pad 77 on its tip rear surface, and a base end part is linked to a leaf spring 78 and fixed to a projecting piece 11a implanted in a carriage which is not shown in a figure with a screw 80 through a patch 79. A recessed part 70a is formed in the rear surface of the pad arm 70 to face the projection 68 of a lever 66 provided on a substrate side which is not shown in the figure. When an unshown cassette is inserted, its end part presses the lever 66 to move forth the projection 68 and the projection 68 engages the recessed part 70a to lower the tip of the lever 70, so that the pad 77 presses an unshown head. When the cassette is drawn out, the lever 70 is elevated and the pad 77 is released from being pressed. Thus, the secure recording and reproduction are carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic disk device, and more specifically, in a small magnetic disk device using a small diameter magnetic disk, a magnetic disk is attached to a magnetic head in conjunction with the mounting operation of a magnetic disk cassette. This invention relates to a magnetic disk device that can be reliably pressed against the magnetic disk.

Floppy disk devices, which are widely used as storage devices using magnetic disks, are used in various electronic devices such as robot equipment, personal computers, word processors, electronic typewriters, and pocket computers, and are useful for increasing the added value of these devices. ing.

With the miniaturization of devices in this type of magnetic disk device, for example, magnetic recording media with a diameter of about 50 mm, that is, magnetic disks (floppy disks) are used, and small magnetic disk devices are used to enable high-density recording. Demand for discs is increasing.

SUMMARY OF THE INVENTION An object of the present invention is to provide a small magnetic disk device as described above, in which a magnetic disk can be pressed against a magnetic head in conjunction with the attachment/detachment of a magnetic disk cassette. There is.

In order to achieve the above object, in the present invention, a pad arm having a pad fixed to the lower surface is lowered in conjunction with the mounting operation of a magnetic disk cassette, and in the mounted state, the magnetic disk is connected to the magnetic head via the pad. We adopted a structure that allows pressing with a predetermined pressure.

Hereinafter, the present invention will be described in detail based on the drawings.

FIG. 1 and the following illustrate a magnetic disk device to which the present invention is applied, and FIG. 1 shows an exploded schematic configuration thereof.

The magnetic disk device according to the present invention can be roughly divided into five parts: a base section 1, a position detection mechanism 2, a holder section 3, a disk holding mechanism 4, and a magnetic disk cassette 5 (hereinafter referred to as , magnetic disks are called floppy disks).

The base l constitutes the main part of the floppy disk device, and is provided with a magnetic recording/reproducing head and a driving source.

The position detection mechanism 2 detects the track position and detects the track position.
A floppy disk cassette (hereinafter abbreviated as cassette) 5 is removably attached thereto, and serves to correctly guide the floppy disk to a head provided on the base side.

Further, the disk holding mechanism 4 exerts a pressing force on the floppy disk, and serves to bring the head and the floppy disk into contact with an appropriate pressing force.

The details of each part will be sequentially explained below.

The base section 1 is assembled with a base 6 as a reference, and is provided with a motor 7 for rotating a floppy disk, the output shaft 8 of which is arranged vertically.

The base 6 has two wooden guide rails 9 that sandwich the motor 7. The IOs are horizontally suspended in parallel, and a carriage 11 is slidably fitted into these guide rails 9 and 10. The guide rail 8.10 has a coil spring 12.
13 is attached to apply a pressing force to the carriage 11 in a direction toward the output shaft 8 of the motor 7.

A magnetic head 14 for recording and reproducing is fixed on the carriage 11, and a roller 15 for tracking in conjunction with a positioning mechanism to be described later is attached to the lower surface of the front side thereof.

A pulse motor 16 for driving the head is attached to one corner of the base 6, and a gear 17 fixed to its output shaft is a gear 1 rotatably supported near the pulse motor 16.
It meshes with 8. The pinion gear 1 is located on the underside of the gear 18.
9 is integrally provided.

Above the motor 7 is the pinion gear 19. motor 7
The printed circuit board 20 is attached while avoiding the output shaft 8. This printed circuit board 20 has a through hole 20a at the negative corner, and this through hole 20a is fitted with a pin 21 protruding from the base 6, and the pin 21 is fixed between the top and bottom of the pin 20 with an E ring 22. be done.

The corner facing the through hole 20a is fixed to the upper end of the side wall 24 of the base 6 with a screw 23, and the other end is also fixed to the base 6 via a screw.
fixed on the side wall or partition wall.

Photodetectors 25 and 28 each consisting of a light receiving element and a light emitting element are attached to the upper and lower parts of the printed circuit board 20.

By the way, the motor 7 has a structure as shown exploded in FIG. 3. The motor 7 has a rotor 27 formed by pressing a magnetic metal such as an iron plate into a flat cylindrical shape, and inside the rotor 27 there are permanent magnets 28, 28 as shown in FIG.
are fixed at equal angular intervals. These permanent magnets 2B, 2
! No. 3 is molded from synthetic resin mixed with magnetic powder, and is excellent in mass production.

The output shaft 8 is fixed to the rotor 27, and a bearing fixed to a yoke 30 of the output shaft 8 is rotatably supported by two upper and lower bearings 32a and 32b fixed to a holder 31. Reference numeral 33 denotes a printed circuit board, which is arranged above the yoke 30, and on which six coils L are mounted, surrounding the through hole 33a into which the holder 31 fits.
1 to L6 are provided, and when a current is passed through these coils L and -L6, a magnetic flux is generated, and in cooperation with the permanent magnets 28 and 29 of the rotor 27, the rotor 27
is rotated.

A disk 34 is fixed to the lower side of the rotor 27, as shown in FIGS. 3 and 4. A pattern 35 in which a total of six black and white zones are alternately arranged at equal angular intervals and a pattern 36 in which a total of 102 black and white zones are formed are concentrically formed on the lower surface of the disk 34.

The printed circuit board 3 corresponds to these patterns 35 and 313.
3, photodetectors 37, 38 are fixed.

The photodetector 37 detects the pattern 36 and detects the rotor 27.
Detects the rotation speed. Moreover, the photodetector 38 is connected to the coil L!
~Detect the positional relationship between L6 and the permanent magnets 28 and 29.

A detection circuit using these photodetectors and coils L and -L6 is shown in FIG. In Figure 5, LED, and T
r5 constitutes a photodetector 38, and 3LE[]2 and Tr6 constitute a photodetector 37.

In FIG. 5, the rotation start signals MO, T ON of the motor 7
is input to the servo circuit 102, IC2 starts operating, and transistors Tr1. Tr3 or blind 2°T
Turn on either between r3 and coil L 1 + L
3 *A current flows through L5 or L2, La, L6, and the magnetic field from the permanent magnet 28.28
Since a magnetic circuit passing through 0 is formed, repulsion and attraction alternately occur between the coil and the magnetic flux Jl, and the rotation of the mouth is detected by the photodetectors 37 and 38.

Now, when the black color of the pattern 35 is detected by the photodetector 3B consisting of LED L and Tr5, the output of Tr5 flows to IC, IC2, and is input to the base of Trl.
Trl is conductive and coil L1 + L 3 + L 5
Current is supplied to Also, when white is detected, Tr
The output of L2.5 turns on IC1, current flows through Tr2, and coil L2. Current flows through L4 and L6. At this time,
Since IC2 is an inverter, its output is 0, Trl is turned off, and no current flows. As a result, no current flows through the coils L 1 + L 31 L 5 .

That is, by changing the information between LED 1 and TrS,
Trl and Tr2 are alternately switched to cause current to alternately flow through odd-numbered coils and even-numbered coils.

By the way, since the rotor 27 needs to maintain a certain rotation speed, Trl and Tr2 are turned on and off.
Tr3 is used as a digital switch, and Tr3 is used as an analog switch to control the current flowing through the coil and rotate the rotor 27 containing a permanent magnet.

Servo ■C3 is used to rotate the motor 7 at a constant speed,
An OR component such as a crystal oscillator is used as part of the servo 103 to oscillate a reference frequency with accurate pulse time intervals, which is input to the servo C3 and the LED 2.
The rotational frequency, which is the detection result of pattern 3B by photodetector 37 consisting of If the rotational frequency generated by rotation in pattern 3B is below the reference frequency, a high current is applied to the base of Tr3, and the coil L! ~ Supply a large current to L6 to increase the rotation speed. Moreover, if the rotational frequency is equal to or higher than the reference frequency, a low current is supplied to the base of Tr3, and a small current is supplied to the coils L1 to L6 to lower the rotational speed.

In this way, the rotation speed of the rotor 27 is detected by the photodetector 37 and the pattern 3B, and compared with the reference frequency by the Sanipo C3, the base current of the Tr 3 is controlled, thereby making the rotation speed constant. .

By the way, specifically, the rotational speed of the rotor 27 during steady state is 2Q4 m5ec, and the number of passes of the pattern 35 to the photodetector 38 during one rotation is 6.
Therefore, the switching period of Trl and Tr2 is 204/[1, which is 34 m5ec. Also, the standard pulse time interval for rotating the motor at a constant speed is 2 m5.
The base of the drive transistor 23 is controlled as the ec interval. Therefore, pattern 38 is divided into 102 equal parts and 2 m long.
This makes it possible to generate 5ec signals.

Since load fluctuations when a magnetic head contacts a floppy disk for recording and reproduction are relatively small, satisfactory rotation can be obtained even if the reference pulse time interval is increased to 2 m5ec or more. Rather, what is difficult is the precision of dividing the pattern 36, the precision of the signal rise time of the photodetector 37, etc., and if these precisions can be improved, there is no problem even if the reference frequency is lowered.

By the way, the permanent magnets 28°29 accommodated in the rotor 27
If it is formed from an integrally molded ring-shaped permanent magnet, the boundary between the magnetic poles becomes unclear during magnetization. Therefore, the Kino-O side is made of a split type, which reduces the mass of the entire permanent magnet and reduces the gap between the magnetic poles. This creates a space between the parts and reduces the weight.

In addition, if such a rotor structure is adopted, it is quite possible that the permanent magnet material will be formed from expensive rare earth materials in order to downsize the motor in the future, so using split permanent magnets will save resources and cost. Connected to down.

Incidentally, a large-diameter gear 39 and a cam 40 are rotatably supported on the output shaft 8 of the motor 7 via a bearing 41, and the gear 39 meshes with the pinion gear 18, so that the rotation of the pulse motor 16 is controlled. communicated. When a single pulse is applied to the pulse motor 16, the gear 17 attached to its output shaft 8 rotates 18 degrees. This rotation is transmitted to gear 39 via gear 18 and pinion gear 18 .

Incidentally, high precision is required for the dimensional accuracy of the relative positional relationship between the magnetic head 14 on the carriage 11 and the output shaft 8 of the motor 7.

The reason for this is that if the dimensional accuracy varies, inter-cassette recording and playback becomes impossible.

Therefore, in order to reduce variations in dimensional accuracy between the magnetic head 14 and the output shaft 8, a cam 4 for driving the carriage is attached to the output shaft 8, which is the rotation center of the floppy disk.
It is optimal to install 0.

Further, by attaching the cam 40 to the output shaft 8 via a bearing 41 with excellent rotational efficiency, the influence exerted from the cam on the motor 7 can be reduced, thereby reducing the rotational load.

By the way, as will be described later, since the cam 40 is engaged with the roller 15 provided on the carriage, the vibration of the output shaft 8 is transmitted to the cam 40, the carriage 11 vibrates, and the vibration is transmitted to the magnetic head 14. However, since the floppy disk is also attached to the output shaft 8, the vibration of the magnetic head and the vibration of the floppy disk are synchronized, and the track position and dimensions do not go out of order.

Incidentally, in practice, when the pulse motor 16 is energized with three pulses, the angle of the cam 40 changes by 9 degrees, and the carriage 11 is set to move by one track.

However, as shown in Fig. 7, the characteristics of a pulse motor is that when one pulse of electricity is applied, the axis of the pulse motor 16 is displaced by 18 degrees, but when the second pulse is applied, it should be displaced by 38 degrees, but due to the inertia of the rotor. And due to magnetization accuracy, 61 rotations are exceeded. Furthermore, when a pulse of 3° is applied, the amount of displacement decreases by 62 degrees from the planned displacement of 54 degrees. Further, the rotation stop position of the pulse motor generally varies slightly, such as when the fourth energization is applied, the pulse motor rotates 72 degrees as planned.

Therefore, if the cam 40 rotated by the pulse motor 1B has a linear relationship between the rotation angle and the amount of displacement as shown in FIG. 8, then a pulse motor with the characteristics shown in FIG. In this case, the stop position of the carriage 11 varies at a rate of ±δ2154@, making it impossible to accurately stop the magnetic head on a predetermined track.

On the other hand, as shown in Figure 9, the relationship between rotation angle and displacement is
If a cam that changes stepwise is used, even if the stop position of the pulse motor is deviated by 62 minutes, the gum will not be displaced to the same extent as this, and variations in the stop position can be drastically reduced. Further, even if bank crash or eccentricity occurs between the power transmission gears, the errors caused by these can be absorbed, and the magnetic head can be accurately aligned with the desired position. As a result, backlash can be provided between the gears in the rotational torque of the pulse motor, so it is possible to reduce the rotational torque and power consumption.

For this reason, in the present invention, a plurality of stepped cam surfaces 40a are formed on the circumferential surface of the cam 40, as shown in FIG. 1θ. The number of these stepped cam surfaces 40a is 40, which in this embodiment is the same as the number of tracks on a floppy disk. Further, the circumferential surface of the cam 40 is on a spiral curve, and gradually becomes smaller from the short diameter part to the long diameter part, and the connecting part between the short diameter part and the long diameter part is a straight part 40b, and the base of this straight part 40b is An arc-shaped recess 4Qc is formed.

By the way, if it is not always known which track position "" the magnetic head 14 currently corresponds to, recording and reproducing errors will occur. Therefore, when the magnetic head is located at a position corresponding to the maximum diameter track of the floppy disk, a reference signal is generated from the device side, and the correspondence state with other track positions is indicated by the number of pulses energized to the pulse motor 16. We devised a configuration in which the position of the magnetic head is determined by memorizing it using a control circuit that does not have a built-in control circuit. This is the disk 42 that constitutes the detection mechanism section 2.

As shown in FIGS. 1 and 23, the disc 42 is attached to the gear 38 in a state in which it is rotatably fitted to the post 43. A detection piece 42a protrudes from a part of the disc 42. This is a structure that reflects light by plating or pasting aluminum foil. This detection piece 42
a is detected by a photodetector 25 provided on the bottom surface of the printed circuit board 20, and a pulse signal is transmitted once per rotation. Therefore, this detection piece 42a can be detected by the photodetector 25 when the magnetic helad 14 is at the maximum diameter track position.

Of course, it is possible to provide a detection piece directly in front of the magnetic head 14 so that the position of the magnetic head can be known, but in this embodiment, the l-track moving distance is 0.125 m+.
e, and the change in the electrical output of the photodetector is minute, requiring an expensive circuit and being impractical.

However, in the present invention, the detection piece 42a rotates slowly together with the gear 38, and the amount of movement per track is approximately 2.5 mm. It became possible to detect.

On the other hand, although the cam 40 is mounted on the gear 38 together with the disk 42, positional deviations may occur due to processing errors or mounting errors, and the above-mentioned detection function may not be fully exerted. For this reason, in the present invention, arcuate long holes 42b are provided in the disc 42 facing each other, and the screws 44 that are screwed onto the gear 38 are fitted into these long holes 42b, so that the disc 40 can be rotated. In this way, the position of the detection piece 42a can be finely adjusted. To perform this fine adjustment, an eccentric pin gauge 101 as shown in FIG. 23 is used. This eccentric pin gauge 101 has an eccentric pin 101a at the lower end. If the diameter of the eccentric pin gauge 101 is D, and the width of the long hole 42c in the radial direction formed in the disk 42 is W, then D=W, and the small hole 31 into which the eccentric pin 101a fits.
1a is formed on the gear 38 side facing the elongated hole 42c.

Therefore, by fitting the eccentric pin gauge 101 into the elongated hole 42c, fitting the eccentric pin 101a into the small hole 39a, and rotating the eccentric pin gauge 101, the disc 42 can be rotated left and right, and the detection piece Fine adjustment of the position of 42a becomes possible.

In the present invention, the tracks of the floppy disk are divided into 40 equal parts with a radius of 15 mm to 20 II1, each track having a length of 0.125 am. Therefore, the magnetic head extends between 15m+a and 20mm around the output shaft 8 of the motor 7.
If the floppy disk is not driven accurately at a pitch of 0.1251, floppy disks recorded with other devices cannot be used.

Also, the maximum track diameter position of the magnetic head is 20 mm.

If the minimum diameter position of 15m+++ is not accurate, it will not be a common specification with other devices. Therefore, the dimensional tolerance of each component between the output shaft 8 and the magnetic head 14 cannot be ignored.

The mounting structure of the roller 15 solves this problem. The mounting structure of the roller 15 is shown in FIGS. 11 to 13. That is, the roller 15 is
It is mounted eccentrically via the shaft 15a. This amount of eccentricity is δ. The 6-screw shaft 45 has a groove 45a at its upper end.
A screwdriver or the like is inserted into the carriage 11 and screwed into a screw hole 11a formed in the carriage 11.

Therefore, when the screw shaft 45 is rotated, the center of the roller 15 can be rotated with a radius δ, and the distance between it and the cam 40 is
That is, the distance between the output shaft 8 to which the cam 40 is fixed and the magnetic head 14 can be reliably finely adjusted. After finishing the fine adjustment, tighten the lock nut 4 on the upper end of the screw shaft 45.
6 and fix it in that position. In this way, variations in processing accuracy and mounting accuracy are absorbed and adjusted.

As shown in FIG. 10, the cam 40 has a plurality of through holes 40e formed around a central hole 40d into which the output shaft 8 is fitted, and a shaft 43a protruding from the post 43 into these through holes 40e. are fitted and fixed by caulking or other methods.

A disk 47 is attached to the upper end of the output shaft 8. The disk 47 has a post 48 on the upper surface and a cylinder 49 on the lower surface, and is fixed by fitting the cylinder 48 to the upper end of the output shaft 8 and screwing a screw 50 from the side.

A disk 51 is fitted into this cylinder 48 between the disk 47 and the cam 40 through its center hole 51a, and the pin 5
It is fixed by caulking 1c. The disc 51 has a detection piece 51b protruding from its circumferential surface. This detection piece 51b is formed as a reflector so that it can be detected by another photodetector 28 provided on the upper surface of the printed circuit board 20.

An arcuate spring piece 52 is punched out from a part of the disk 51, and a pin 53 is formed on the upper surface of the free end side of the spring piece 52.
is installed protrudingly. The pin 53 is fitted into a through hole 47a formed in a portion of the disk 47 and faces above the disk 47. This screw 753 is fitted into a through hole formed in the hub of a floppy disk housed in a cassette, which will be described later, and transmits the rotation of the output shaft 8. This disk 51 is fixed to the post 43 together with the cam 40.

A detection piece 51b protruding from the disc 51 is detected by the photodetector 26 every rotation of the output shaft 8 and generates a start position signal.

On the other hand, the holder portion 3 has a structure as shown exploded in FIG.

That is, the holder portion 3 is assembled based on the substrate 54. The substrate 54 is press-molded from a metal plate, and side plates 55 are formed on both left and right sides thereof. These side plates 5
Through holes 55a are formed at opposing positions on the distal end side of the shaft 5, and a shaft 58 is fitted into these through holes. Both ends of the shaft 56 are rotatably fitted into through holes 6a formed in the left and right side plates of the base 6.

Further, a projecting piece 57 is provided in the center of the side plate 55,
A spring 58 is stretched between this protruding piece 57 and a protruding piece 6b protruding from the base 6.
It provides a pulling force to the base 6 side.

A through hole 54a into which the disk 47 can be inserted is formed in the center of the substrate 54, and an elongated hole 54b into which a magnetic head can be inserted is formed on the side of the hole 54a.

Bent pieces 54c, 54c bent upward are formed on the free end side edge of the substrate 54, and bent pieces 55b are formed on the edge of the side plate 55 in a state of expanding left and right. A bent piece 55c bent downward is formed on the lower side of the bent piece 55b.

These bent pieces 54c, 55b, and 55c serve as guides when the cassette 5 is installed.

Furthermore, guide pieces 55d for guiding the cassette 5 are formed at the lower ends of the side plates 55, respectively.

Lever 513.80 is attached to the outside of the left and right side plates 55. These levers 51a, 130 have a central part,
A through hole 59a and an EIOa are formed along the longitudinal direction, and a guide pin 61 fixed to the protruding piece 57 is fitted into each of these through holes. Each lever 59
．． A protrusion 59b is provided at the tip of 80 to protrude downward.
A spring 62 is stretched between Bob and the protrusion 57, and constantly pulls the respective levers 59 and 130 toward the front.

Each lever 59. There is a notch 5 along the longitudinal direction on the front edge of the EIO! ac and BOc are formed, and a guide bin 63 fixed to the side plate 55 is formed in these notches.
is inserted.

Further, L-shaped bent portions 58d and BOd bent at right angles toward the board 54 are formed at the tip of the levers 58 and 60, and these bent portions 51]d and Sod are formed on the side plate 58. 55 into a notch 55e formed on the top surface of the tip of the cassette 55 so that the tip faces the inside of the side plate 55, and when the cassette 5 is installed, both sides 5a and 5b of the tip of the cassette 5 are inserted.
engaged with.

Furthermore, each lever 59. Projecting pieces 59e and 80e are provided on the front edge of the EIO, and these projecting pieces 58
e.

60e is located at a position where it can be engaged with one of the guide rails 10 provided on the base 6 side.

Also, between the protruding pieces 59b and 513e of each lever 58 and 8
0b.

Between 80e and 80e are guide portions 59f and 130F that come into contact with a guide roller of an operating lever, which will be described later.

By the way, a protruding piece 84 is provided on the tip end of the base plate 54 at approximately the center thereof, and a lever 8B is rotatably supported on the tip end via a pin 65 at the center thereof. This lever 86 is formed approximately in the shape of a "〈" character, and one end thereof has a bent portion 5 formed at the tip of the lever 59.
1] A pin 87 that is slidably fitted into the elongated hole 59g formed in d is provided to protrude downward.

Further, the upper surface of the other end of the lever 68 will be described later. , a protrusion 88 is provided to engage with the pad arm.

On the other hand, the disc holding mechanism portion 4 is constructed as shown in FIG.

The disc holding mechanism 4 is composed of a leaf spring 88 and a pad arm 70. The leaf spring 68 is formed into a substantially quadrilateral shape, and the leaf spring 8 is inserted into the through hole Ha formed in the center of the leaf spring 68.
The post 71a of the rotating body 71 is fitted from the bottom of the plate spring 68, and the boss 71a is a through hole of the retaining ring 72 located above the leaf spring 68. 2a, and the presser ring 7 is secured by a screw 73.
2 and is rotatably attached to the leaf spring 88. An arcuate portion 71b is formed on the circumferential surface of the rotating body 71, and this portion is connected to the through hole 54 of the substrate 54 of the holder.
a to ensure smooth insertion when the cassette 5 is installed. This rotating body 71 comes into contact with the hub of a floppy disk housed in a cassette, which will be described later, and plays the role of supporting the rotation of the floppy disk from above.

The leaf spring 89 has three through holes 69b formed therein.
Pins 74 protruding from the upper surface of the substrate 54 are fitted into these through holes 68b and fixed by caulking.

A spring piece 75 is protruded from the center of the tip of the leaf spring θ8, and this spring piece 75 is fitted into the notch 54d formed in the base plate 54, and serves to hold down the cassette 5.

Further, spring pieces 7 are provided at both left and right ends of the other end of the leaf spring 69.
Ei and 7B are formed and serve to hold down the cassette 5 from above.

The plurality of punched grooves formed between the through holes 89a provide elasticity to the portion surrounding the through hole E19a, and are used to elastically maintain contact between the rotating body 71 and the hub of the floppy disk. It is.

The pad arm 7o has a pad 77 on the lower surface of its tip, and a leaf spring 78 is connected to its base end.
It is fixed to a protruding piece 11a provided protrudingly from one end of 1. The pad 77 corresponds to the magnetic head 14, and the pad arm 7
Four portions 70a are formed on the lower surface of 0 at positions that can correspond to the protrusions 68 of the lever 68 provided on the substrate 54 side. The pad 77 passes through a notch 89d formed on the side edge of the leaf spring 88 and fits into the elongated hole 54b of the substrate 54, and is disposed opposite the magnetic head 14 to press the floppy disk from above.

On the other hand, the cassette 5 has a structure as shown exploded in FIG. 14.

That is, the cassette 5 is a cassette half 81. made of synthetic resin or the like. f12, through holes 81a and 82a into which the disk 47 and rotating body 71 are fitted are formed at opposing positions in the center thereof, and a magnetic head and pads are fitted into the vicinity of 7. Openings 81b and 82b are formed. Inside the upper cassette half 81, a disc-shaped liner 83 is fixed at multiple locations indicated by reference numeral 83a via an adhesive or the like. The liner 83 has a through hole 83b at a position corresponding to the through hole 81a of the cassette half 81, and an opening 83c at a position opposite to the opening 81b. The spring pieces 84 and 85 are connected to the opening 83.
It is placed with c in between. Base end 8 of spring piece 84.85
4a and 85a are fixed to the lower surface of the cassette half 81,
Its free end side presses the liner 83 downward on both sides of the opening 83c. The role of these spring pieces 84, 85 is to press the liner 83 against the floppy disk on both sides of the magnetic head and pads that sandwich the floppy disk from above and below, thereby maintaining reliable contact between the floppy disk and the magnetic head.

This state is shown in FIG.

Liners 8El and 8fll are provided on the lower cassette half 82 side with a through hole 82a in between, and a small hole 82c is formed at a position that does not contact the floppy disk. The upper end portion of the pin 21 protruding from the base 6 side is fitted into this small hole 82c, which serves as a positioning hole for mounting the cassette.

A floppy disk 87 is accommodated between the liner 83 and the lower cassette half 82. The floppy disk 87 has a hub 88 in the center, into which the boss 48 of the disk 47 is fitted, and into which the spring piece 52 of the disc 51 protrudes into a through hole 138b formed in the vicinity. The provided pin 53 is fitted.

Incidentally, the base 6 side is devised to constitute a mounting reference surface when a cassette is mounted. That is, 1st B
As shown in the figure, the pin 21 protruding from the base 6 not only serves to attach the printed circuit board 20, but also has a protrusion 21b protruding from its upper edge 21a that fits into the small hole 82c of the cassette half 82. The upper edge [19a
, 90a are set to be in the same plane as the upper edge 21a of the pin 21, thereby forming a mounting reference plane. pin 21
and struts 89.904 are arranged to form each vertex of a triangle, and the upper edges 89a, 90a of struts 89.90
Projecting pieces 89b, 90b are provided on the outside of the cassette 5.
It plays the role of positioning.

Therefore, when the cassette 5 is lowered together with the holder toward the base 6 by the operation described later, the cassette 5 is reliably supported on a certain base surface by the pins 21 and the supports 89 and 90, and also by the protrusions 21b and the protrusions. Accurate positioning is achieved by the pieces 8fllb and 90b.

By the way, an operating lever 81 is provided on the base 6 side. The operating lever 81 is formed as a substantially U-shaped frame and is rotatably supported on both sides of the front end of the base 6 via pins 82 . A roller 83 is rotatably attached to the inner surface of the pin 82 at a position remote from the pin 82.

This roller 93 is connected to the guide portion 5 of the lever 5θ, 60.
It is located in contact with 9f and 60f.

The operating lever 91 has the tendency to rotate clockwise in FIG. 1 about the pin 82 due to its own weight.

Next, the operating method and operation of the floppy disk device according to the present invention constructed as above will be explained.

Before the cassette 5 is installed inside the holder, the front end of the board 54 is lifted upward as shown in FIG. 17, and the lever 58. θ0 is the spring 82
It is in a state where it is pulled towards you by the tensile force of. but,
The lower ends of the protrusions 59e and 8oe of the lever 59 and flO are in contact with the guide rail 10, and do not descend even when the tensile force of the spring 58 is applied, maintaining this forest state.

At this time, the operating lever 81 is rotated to the front side, and the roller 93
is in contact with the front corner of the guide portion 59f, eOf.

In this state, the lever 88 is rotated counterclockwise in FIG. 2 about the pin 65 via the pin e7 due to the movement of the lever 59 toward the front side, and the protrusion 68 is moved to the 21st position.
As shown in the figure, the pad arm 70 is in contact with the back side of the recess 70a on the lower surface of the pad arm 70, and the pad arm 70 is connected to the leaf spring 78.
The pad 77 is pushed up in a direction away from the substrate 54 against the pressing force of the pad 77.

In this state, when the cassette 5 is inserted into the guide portion formed by the bent pieces 54c, 55b, and 55c at the front end of the board 54, the tips 5a and 5b of the cassette 5 are pushed into the levers 59 and 59.
When the lever 59.80 contacts the bent pieces 511d and 130d on the rear side of the EIQ and further pushes the cassette 5, the lever 59.80 moves inward against the tensile force of the spring 62. This limit of movement is regulated by long holes 59a and 60a. Eventually, as the lever 59.80 moves forward, the projections 58e, 60e begin to separate from the guide rail 10, as shown in FIG.

At the same time, as the lever 59 moves forward, the lever 86 is rotated clockwise in FIG. 2 via the pin 67, and as shown in FIG.
It starts to fit inside.

As a result, the tip of the pad arm 70 is lowered by the force of the leaf spring 78, passes through the elongated hole 54b of the board 54, fits into the opening 81b of the cassette 5, and the floppy disk 8
Begin contact with 7.

Eventually, when the levers 59 and 80 are pushed to the farthest position, the protrusions 5 of each lever are pushed in as shown in FIG.
9e and EIOe are separated from the guide rail lO, and the holder part 3 is moved around the board 54 by the tensile force of the spring 58.
is pulled downward.

At this time, the protrusion 21b of the pin 21 is fitted into the small hole 82c formed on the back surface of the front end of the cassette 5, and the lower surface of the cassette 5 is fitted onto the edge 21a of the pin 21 and the upper edge of the support 88. are in contact with each other, and the cassette 5 is set on the reference surface. At the same time, both ends 5c and 5d on the back side of the cassette 5 are positioned and mounted in the left-right direction by the projecting pieces 89b and 11Ob of the support 8111.90.

In this state, as shown in FIG. 15, the floppy disk 87 is sandwiched between the pad 77 and the magnetic head 14 from above and below, and is pushed through the liner 83, which is pressed on both sides by the spring pieces 84 and 115, so that it is not exposed to the magnetic head. 1
4, the floppy disk 87 is slightly bent and comes into secure contact with the magnetic head 14.

In this state, magnetic recording and reproduction are performed.

If you want to remove the cassette 5, press the operation lever 81 downwards and rotate it clockwise about the pin 82 while the cassette is completely installed as shown in FIG. EiO is pushed upward and is also pulled back to the front side by the force of the spring 62. Eventually, the protrusion 59e of each lever
, 80e is separated from the guide rail 10, and the entire holder part is locked with the front side raised.

At the same time, the pad arm 70 is also raised by moving the lever 58.80 toward the front, and the cassette 5 is pushed back toward the front by a predetermined distance. When the cassette 5 is picked up and pulled out, the spring piece 75 of the leaf spring 89 restrains the cassette 5.
Since it is only 76, it can be easily drawn out.

As is clear from the above description, according to the present invention, the pad is provided with a pad that separates from the magnetic disk before mounting the magnetic disk and reaches a position where it presses the magnetic disk in conjunction with the operation of mounting the magnetic disk. Since the structure is equipped with an arm, the magnetic disk can be automatically pressed against the magnetic head with a predetermined pressing force simply by inserting and removing the magnetic disk cassette, ensuring reliable magnetic recording and playback. can be done.

[Brief explanation of the drawing]

The figures are for explaining one embodiment of the present invention; FIG. 1 is an exploded perspective view of the base portion, FIG. 2 is an exploded perspective view of the holder portion,
Fig. 3 is an exploded perspective view of the motor, Fig. 4 is a perspective view of the lower side of the motor, Fig. 5 is a circuit diagram showing the connection between the photodetector and the coil, and Fig. 6 is the base. Fig. 7 is a diagram showing the relationship between the number of input pulses of the pulse motor and the rotation angle, and Fig. 8 is a diagram showing the relationship between the rotation angle and displacement amount of a general cam shown as a comparative example. 9 is a diagram showing the relationship between the rotation angle and displacement amount of the cam applied to the present invention, FIG. 1θ is a plan view of the cam, and FIG. FIG. 12 is a perspective view of the roller seen from below, FIG. 13 is a side view showing the arrangement of the cam and roller, FIG. 14 is an exploded perspective view of the cassette,
Fig. 15 is a partially enlarged longitudinal sectional side view of the cassette, Fig. 16 is a perspective view showing the reference plane setting structure for mounting the cassette, and Fig.
7 to 18 are side views explaining the operation, FIG. 20 is a partially longitudinal side view showing the cassette installed state, FIGS. 21 and 22 are side views explaining the operation of the pad arm, and FIG.
FIG. 3 is a perspective view illustrating a fine adjustment method using an eccentric pin gauge 6 1...Base part 2...Position detection mechanism part 3.
...Holder part 4...Disc holding mechanism 5...
・Cassette 6...Base 7...Motor 8...
・Output shaft 8. lO... Guide rail 11.
... Carriage 14 ... Magnetic head 15 ...
Roller 16... Pulse motor 20... Printed circuit board 25.28... Photodetector 21... Pin 27... Rotor 28, 29... Permanent magnet 34... Disc 40... Cam 47... Disc 54... Board 58. eo, 1(El
... Lever 68 ... Leaf spring 70 ... Pad arm 77 ... Pad 81.82 ...
・Cassette half 83.88...Liner 87・
...Floppy disk 88...Hub 89.90
...Strut 91...Operation lever Fig. 20 Fig. 21 7゜

Claims (1)

[Claims] In a magnetic disk device in which a magnetic disk cassette is removably attached via a holder, one end of the cassette is fixed to the device fixing part via a spring above the inner end of the holder, and the other end is fixed to the device fixing part via a spring. A pad arm having a pad for pressing the magnetic disk is provided on the lower surface, and this pad arm can be moved toward and away from the magnetic disk via a lever that is linked to the operation of attaching and detaching the magnetic disk cassette. magnetic disk device.