JPH0532829B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk device, and more particularly to a magnetic disk device equipped with a magnetic head for recording on or reproducing information from a cassette-type magnetic disk.

[Prior art]

Recently, imaging devices such as solid-state image sensors and image pickup tubes,
In combination with a recording device that uses a magnetic disk, which is inexpensive and has a relatively large storage capacity, as a recording medium, the subject is still photographed purely electronically and recorded on a rotating disk, and images are reproduced using a separate television system or printer. Electronic still camera systems have been developed.

In an image recording or reproducing system using such a magnetic disk, a disk with a diameter of about 50 mm is used, and this magnetic disk has a recording pattern of 1 track to 52 tracks from the outer circumferential side to the inner circumferential side. is formed. The head feed pitch is approximately 100 μm, which is much smaller than the feed pitch of a normal floppy disk, and therefore the magnetic head must be moved with extremely high precision. The home position, which is the start position (movement start position) of the magnetic head, is set at a predetermined position on the outer circumferential side from 1 track, and the end position, which is the end position (movement end position), of the magnetic head is set at 52.
It is set at a predetermined position on the inner circumferential side from the track. Therefore, in the magnetic disk device, it is necessary to detect the home position and the end position, and to stop the feeding operation of the magnetic head at the home position or the end position.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and provides a magnetic disk device that detects the home position and end position of a magnetic head and stops the feeding operation of the magnetic head at the home position or the end position. The purpose is to propose.

[Structure of the invention]

In order to achieve the above object, the present invention provides a head carriage that includes a rotational drive source and a magnetic head for recording or reproducing data on or from a rotating magnetic disk and moves the magnetic head in the radial direction of the magnetic disk.
A gear reduction device that constitutes a power transmission mechanism that connects the rotary drive source and the head carriage, a first switch that detects the home position of the magnetic head and stops the rotary drive source, and detects the end position of the magnetic head. the second to stop the rotational drive source.
a contact portion formed on a reduction gear of a gear reduction device that rotates at less than one revolution per one stroke of movement of the magnetic head, the contact portion abutting the first switch at a home position of the magnetic head; The magnetic head is characterized in that the end position of the magnetic head contacts the second switch to operate the second switch.

〔Example〕

Preferred embodiments of the magnetic disk device according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a plan view showing this embodiment, and FIG. 2 is an enlarged sectional view taken along the upper line in FIG. 1. As shown in FIG. 1, a main body 10 of a cassette type magnetic disk recording device, such as an electronic camera or a reproducing device, has a rectangular shape. As shown by the imaginary line in FIG. 1, a disk pack 12 is mounted on this main body 10 so that the disk stored in the disk pack 12 is engaged with the rotary shaft 16 of the disk drive motor 14 so that it can rotate freely. be done.

First, the structure of the disk pack will be explained.As shown in FIGS. 3A and 3B, the disk pack 12 has a main body 18 and a magnet rotatably housed therein. It consists of 20 disks,
It is placed on the main body 10 of an electronic camera or the like with its surface facing upward so that the end surfaces indicated by arrows A in FIGS. 1 and 3A are common.

The magnetic disk 20 is composed of a disc-shaped magnetic recording material 22 having a recording layer formed on its back surface, and a center core 26 provided with a hole 24 in the center to engage the rotating shaft 16 of the disk drive motor 14. The pack body 18 has openings 28 and 30 for exposing the center core 26 of the magnetic disk 20, and openings 32 and 34 for exposing the recording surface and non-recording surface of the magnetic disk 20. A magnetic head is made to protrude from 34 onto the recording surface to perform recording or reproduction. The member indicated by the two-dot chain line 36 is the shutter, and the pack body 18
When inserted into the playback device and taken out, the shutter 36
slides to open and close apertures 32 and 34.

Reference numeral 38 denotes a counter display section for the number of recorded tracks, which is rotated by the drive of a head feed mechanism provided in the electronic camera body, for example, and displays the number of recorded tracks. Reference numeral 40 denotes an erroneous recording prevention claw similar to the erroneous erasure prevention claw of an audio cassette provided on the back side of the pack body 18, and the presence or absence of the color of the nail is detected by a detection mechanism such as the camera body or the player body. This prevents erroneous recording. 42
is a field/frame switching detection section, and the position of the member 44 sliding on this switching section 42 is detected by a detection mechanism in the camera body or the playback device body so as to obtain a signal for switching between field/frame recording or reproduction. It's summery.

As shown in FIG. 1, a head carriage 46 is slidably disposed in the main body 10 of the apparatus.
That is, the head carriage 46 is connected to the disk pack 12.
The device is equipped with a magnetic head 48 for writing or reading information on the magnetic disk 20 inside, and is slidable along a guide bar 50 fixed to the main body 10 of the device. The rotational force of the stepping motor 47 shown in FIG. 2 is transmitted to the head carriage 46 via a planetary gear reduction device and a rotational-linear motion conversion device, which will be described below, and the head carriage 46 is slightly fed.

First, the planetary gear reduction device will be explained with reference to FIG. 2. Output shaft 47 of stepping motor 47
A pinion 49 is provided as a sun gear. Around this pinion 49, there is a pinion 4
A fixed internal gear 51 is disposed concentrically with 9.
A first planetary gear 52 meshes with the outside of the pinion 49, and this first planetary gear 52 is connected to the fixed internal gear 5.
It meshes well with 1. Further, a rotating internal gear 54 is arranged concentrically with the fixed internal gear 51, and this rotating internal gear 54 is pivotally supported by the device main body 10 via a shaft 56. A second planetary gear 58 meshes with the outside of the pinion 49, and this second planetary gear 58 also meshes with the rotating internal gear 54. The first planetary gear 52 and the second planetary gear 58 are attached to shafts 62 and 64, respectively, on a retainer 60 as a common arm member.
It is pivotally supported through. Therefore, the rotational driving force from the stepping motor 47 is transmitted from the pinion 49 to the planetary gear 52, and the planetary gear 52 rotates while meshing with the pinion 49 and the fixed internal gear 51, and also revolves around the pinion 49. Rotate the retainer 60. The second planetary gear 58 rotates on its own axis while being affected by the movement of the retainer 60, and also revolves around the pinion 49 at the same speed as the first planetary gear 52, and reduces its rotational force to the rotating internal gear 54. I'm starting to tell people that. External teeth 62 are formed on the outside of the rotating internal gear 54. This external tooth 62 is a sector gear 6 having a shaft 64 as its center of rotation.
It meshes with 6.

Next, FIG. 1 will mainly explain the rotational-linear motion conversion device. A pulley 68 is formed on the sector gear 66, and a steel belt 7 is attached to the pulley 68.
0 is attached by winding α. That is, the right end of the steel belt 70 in FIG. be done. The steel belt 70 is further fixed to a pulley 68 integral with the sector gear 66 by screws 78. Therefore, when the external gear 62 rotates, the sector gear 6
6 also rotates accordingly, and since the head carriage 46 is connected to the sector gear 66 via the steel belt 70, the amount of rotational movement of the sector gear 66 is converted into a linear movement amount, and the head carriage 46 moves.

Furthermore, an arm 82 as a contact portion is provided on the outer periphery of the arcuate portion 80 of the sector gear 66 to protrude radially outward. On the other hand, a home position switch 84 and an end position switch 86 are arranged at the pivoting portion of the arm 82. When the magnetic head 48 is in the home position (the first
(position shown in the figure), home position switch 84
, the home position switch 84 is closed, and the driving of the stepping motor 47 is stopped. Further, when the magnetic head 48 moves in the direction of arrow B (inner circumferential direction on the magnetic disk 20) and is located at the end position, the arm 82 contacts the end position switch 86, closes the end position switch 86, and closes the end position switch 86. The drive of the ping motor 47 is stopped.

The home position switch 84 and the end position switch 86 are composed of leaf switches, and the structure thereof will be explained below with reference to FIG. 4. The leaf switches (home position switch 84, end position switch 86) are composed of a movable contact 88 made of a phosphor bronze plate and a fixed contact 90, and a contact part 92 made of resin is formed at the upper end of the movable contact 88. There is. The movable contact 88 and the fixed contact 90 are integrally molded using a resin 94, and the lower surface of the resin 94 includes a boss 96, a lower end 98 of the movable contact 92, and a lower end 1 of the fixed contact 90.
00 stands out. The leaf switch constructed in this manner is installed on the printed circuit board 102. In this case, the boss 96 and the lower ends 98, 100 function to position and prevent the leaf switch from rotating, and the leaf switch is attached to the printed circuit board 102 by soldering the lower ends 98, 100. In the leaf switch configured in this way, when the arm 82 comes into contact with the contact portion 92, the movable contact 88 bends toward the fixed contact 90 as shown by the imaginary line, and when the movable contact 88 comes into contact with the fixed contact 90, the leaf switch is turned on.

The operation of the embodiment according to the present invention constructed as described above is as follows.

First, the rotational force of the stepping motor 47 is transmitted to the pinion 49, and the rotational force of the pinion 49 is transmitted to the fixed internal gear 51, the rotating internal gear 54, the first and second planetary gears 52, 58, and the retainer 60. It is decelerated via a planetary gear reduction device. This reduced rotational force is transmitted to the sector gear 66, which moves the head carriage 46 one track at a time along the guide bar 50 by means of a rotary-to-linear motion converter. That is, for example, if the stepping motor 47 is moved 16 steps by the speed reduction device, and the speed is reduced to 1/64 by the planetary gear speed reduction device, the head carriage 46 can be moved 100 microns. In this way, one magnetic disk 20 in the disk pack 18 is
Recording or reproduction can be performed by moving the magnetic head 48 track by track (100 microns).

Further, when the magnetic head 48 is located at the starting end position, that is, the home position, the arm 82 comes into contact with the home position switch 84 and the home position switch 84 is closed, and the stepping motor 47
The feed drive is stopped. This causes the magnetic head 48 to stop moving at the home position. When the magnetic head 48 is at the end position, the arm 82 rotates counterclockwise from the position shown in FIG. 1 and comes into contact with the end position switch 86. Close, and the feeding drive of the stepping motor 47 is stopped. This causes the magnetic head 48 to stop moving at the end position.

According to the embodiment, since the arm 82 is provided to protrude outward in the radial direction from the fan-shaped gear 66, the arm 82 magnifies the amount of feed of the magnetic head 48. As a result, the accuracy of the leaf switch can be further improved by the action of the arm 82.
In the above embodiment, the arm 82 is connected to the sector gear 66.
However, the present invention is not limited to this, and any member that rotates less than one rotation per stroke of the magnetic head 48 in the planetary gear reduction device may be used. It may be a member. Further, the shape of the contact member is not limited to the arm 82, but may be any shape as long as it can close the first and second switches.

As explained above, according to the magnetic disk device according to the present invention, a contact portion is formed on the reduction gear of the gear reduction device that connects the rotational drive source and the head carriage, and this contact portion is formed when the magnetic head is located at the home position. The first switch is actuated to stop the feeding of the magnetic head, and when the magnetic head is at the end position, the second switch is actuated to stop the feeding of the magnetic head. The magnetic head can stop feeding at the home position and end position.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing the structure of this embodiment, Fig. 2 is an enlarged sectional view taken along the top line of Fig. 1, and Fig. 3
3B are front and back views of the magnetic disk pack used in the above embodiment of the present invention, and FIG. 4 is a sectional view of the leaf switch used in this embodiment. DESCRIPTION OF SYMBOLS 10...Main body of magnetic disk recording or reproducing apparatus, 20...Magnetic disk, 46...Head carriage, 47...Stepping motor, 48...Magnetic head, 66...Sector gear, 82...Arm, 84...First
Home position switch as a switch for
86...End position switch as a second switch.

Claims (1)

[Claims] 1. A rotary drive source, a head carriage that includes a magnetic head for recording or reproducing information on a rotating magnetic disk and moves the magnetic head in the radial direction of the magnetic disk, and gears constituting a power transmission mechanism that connects the rotary drive source and the head carriage. a reduction gear,
A first switch that detects the home position of the magnetic head and stops the rotational drive source, a second switch that detects the end position of the magnetic head and stops the rotational drive source, and one-stroke movement of the magnetic head. and a contact portion formed on a reduction gear of a gear reduction device that rotates at less than one revolution relative to the magnetic head, and the contact portion contacts a first switch when the magnetic head is in the home position, and the first switch is activated. 1. A magnetic disk device characterized in that when the magnetic head is located at an end position, the magnetic head comes into contact with a second switch and operates the second switch.