GB2276756A

GB2276756A - Magnetic disc drive apparatus

Info

Publication number: GB2276756A
Application number: GB9406533A
Authority: GB
Inventors: Junichi Miyata; Takuro Kohyama; Katsuhiko Fujinuna; Maki Wakita
Original assignee: Citizen Watch Co Ltd
Current assignee: Citizen Watch Co Ltd
Priority date: 1993-04-01
Filing date: 1994-03-30
Publication date: 1994-10-05
Anticipated expiration: 2014-03-30
Also published as: GB2276756B; HK44297A; GB9406533D0

Abstract

A disc drive apparatus comprising a carriage with upper and lower arms 72, 74 each carrying a magnetic head 64, 66, a carriage driving mechanism which comprises a motor and feed screw arrangement 98, 104 for driving the carriage radially across the disc, a zero track sensor 108 for detecting the position of the carriage where the magnetic heads are stationed on the outermost track of the disc, and a spring means 82 which has a coil portion 82a mounted within the carriage body for pressing the upper arm against the lower arm. The disc driving motor (62) comprises a motor body (62a) and a pulley (114) which has a smaller diameter than the motor body. An interface connector (112) is at least partly positioned in the space around the pulley. This arrangement reduces the overall size of the disc drive. <IMAGE>

Description

MAGNETIC DISC DRIVE APPARATUS This invention relates to a disc drive apparatus for rotationally driving a disc type of recording medium, such as a floppy disc used as a recording medium for a computer or office automation equipment, and recording and reading out the information therein and therefrom, and more particularly to an arrangement of the components of the disc drive apparatus.

Due to the increase of personal usage of computer or information processing equipments, miniaturization of these equipments has been developed. Floppy discs or fixed magnetic discs are used as a recording medium for such equipments, which requires an apparatus for rotational driving and for read/write operation.

In a typical floppy disc drive apparatus, a floppy disc is stored in a cassette which is inserted and removed to and from the disc driving apparatus, and an inserting/removing mechanism is provided for carrying the cassette forward and backward between the inserting/removing position and the place where the disc is rotationally driven. A shutter opening and closing mechanism is also installed for opening the shutter provided on the cassette when inserting the disc to directly expose the magnetic disc to the read/write heads. The disc drive apparatus also comprises one or more heads for recording information onto a plurality of tracks formed in concentric circles on the disc and reading out the recorded information, and a carriage driving mechanism for driving a carriage mounting the head thereon to align the head onto a desired track. Further, a driving mechanism for rotationally driving the disc and an interface connector for communicating with peripheral equipments are also included in the disc drive apparatus.

As is mentioned above, miniaturization of computer or information processing equipments is desired in accordance with the increase of personal usage, and the like demand is applied to a disc drive apparatus. However, a disc drive apparatus comprises many mobile mechanisms as described above, and it is difficult to miniaturize.

This invention provides a miniaturized disc drive apparatus in which each of the mobile mechanisms are effectively arranged. In the improved disc drive apparatus, miniaturization is achieved by rearranging the positions of the carriage carrying the heads at the edge thereof, the carriage driving mechanism for driving the carriage to align the heads onto a desired track on the disc, and the zero-zero track sensor for detecting that the heads are positioned onto the outermost track (zero-zero track), and by adding a new composition.

The carriage driving mechanism comprises a carriage driving motor, a feed screw aligned with the carriage driving motor and parallel to the carriage moving direction which is rotationally driven by the carriage driving motor, a feed screw receiver fixed onto the carriage and engaging with the feed screw, and a zero-zero track sensor for detecting the carriage position where the heads are opposed to the outermost track of the recording medium.

The carriage driving motor is arranged parallel to the feed screw, and each of the components are arranged so that when the carriage is at the backmost position, the back end of the carriage is positioned at the same position as or backward of the carriage driving motor and the zero-zero track sensor.

The carriage consists of a carriage body having a lower arm holding a lower head at the edge thereof, an upper arm rotatably supported by the carriage body and holding an upper head at the edge thereof, and a presser spring for forcing the upper head to the lower head.

The coil portion of the presser spring is housed inside the carriage body, and the presser bar is positioned inside the carriage frame.

According to the foregoing construction, when the carriage is at the backmost position, its back end is positioned in alignment with the back end of the disc drive apparatus. In other words, each of the components are positioned so as not to backwardly project from the back end of the carriage when the carriage is at the backmost position.

Since the forward and backward movement of the carriage is essential movement for positioning the heads opposed to a desired track, the depth of the disc drive apparatus is no less than the length to the backmost position of the carriage.

That is, when the back end of the carriage at its backmost position coincides with the rear end of the disc drive apparatus, the depth of the apparatus becomes minimum and miniaturization of the apparatus is realized.

Further, in the disc drive apparatus of this invention, the disc drive motor for rotating the disc (recording medium) and the interface connector are effectively arranged. The disc drive motor comprises a motor body and a pulley fixed on the output shaft of the motor. The outer diameter of the pulley is smaller than that of the motor body, and the total shape of the drive motor is overlaid with two different sized of cylinders. A space is created around the. pulley because of its smaller diameter, which is used for storing at least a portion of the interface connector. Thus, a space inside the disc drive apparatus is effectively used to minimize the size of the apparatus.

The following is a description of a specific embodiment of the invention, reference being made to the accompanying drawings, in which: FIG. 1 is a plan view of a disc drive apparatus according to a preferred embodiment of the invention; FIG. 2 is a perspective view of a cassette inserting/removing mechanism and showing a slide plate, carrier, and a cassette; FIG. 3A is a cross sectional side views showing positional relationship between the projection of the carrier and the recesses of the slide plate and the frame, for explanation of the inserting and removing of the cassette; FIG. 3B is a cross sectional side views showing positional relationship between the projection of the carrier and the recesses of the slide plate and the frame when the cassette is at the loaded position, where the projection is at lower position; FIG. 4 is a cross sectional view of the carriage; and FIG. 5 is a cross sectional side view showing a positional relationship between the disc drive motor and the interface connector.

Referring to FIG. 1, a carriage, a carriage driving mechanism, a cassette inserting/removing mechanism, disc driving mechanism, and so on are shown inside a frame 10.

These components will be described below in detail.

A cassette 22 storing a magnetic disc is inserted from the direction B shown in FIG. 1 and held onto a carrier 12, and then fixed onto a chuck 14. When removing the cassette, an injection button 16 is pushed from the direction B which moves the slide plate 18 to move the carrier 12 to the removal position. This operation will be explained in more detail with reference to FIGs. 2, 3A and 3B.

The cassette 22 storing the magnetic disc 20 is inserted into the carrier 12 from direction B of FIG. 2. Projections 24 are provided on each corner of the carrier 12, which are engaged with recesses 26 formed onto each corner of the slide plate 18. The projections 24 are also engaged with guide grooves 28 (shown in FIGs. 3A and 3B) of the frame 10.

Accordingly, the projections 24 can move up and down along the guide grooves 28. In other words, the carrier 12 is allowed to move relative to the frame only up and down along the guide grooves. FIG. 3A shows a carrier position at the upper portion of the groove when the cassette is inserted or removed.

When the cassette is inserted, the leading edge of the cassette touches the edge 32 of the lock lever 30 (shown in FIG. 1) which is rotatably supported onto the shaft 34. As the cassette is further advanced, the lock lever 30 rotates clockwise around the shaft 34 against the tensile strength of the presser spring 40. On the other edge of the lock lever 30, an engagement cam 36 is provided which engages with a cam receiver 38 provided on the bact end of the slide plate 18.

The slide plate is always pulled to the opposite direction of direction B by the presser spring 42, but the engagement of the cam 36 with the cam receiver 38 prevents the slide plate from moving to the opposite direction of direction B. When the cassette is further advanced to the loading position shown by dashed line 22a, the engagement cam 36 disengages from the cam receiver 38 and the slide plate 18 moves to the opposote direction of direction B using the tensile force of the presser spring 42. This movement of the slide plate 18 forces the projections 24 of the carrier 12 toward the lower position along the recess 26 of the slide plate as shown in FIGs 2, 3A and 3B. Since the carrier 12 is forced downward by a presser spring (not shown) hooked by the hook 44 located on the side wall of the carrier 12, the carrier 12 securely moves downward according to the movement of the slide plate 18 to fix the cassette 12 at a predetermined position on the chuck 14. This action is shown in FIG. 3B, and the projection 24 of the carrier 12 is positioned at the bottom of the frame 10.

When the cassette is inserted, the edge 32 of the lock lever 30 touches the notch 48 of the cassette 22. In accordance with the rotation of the lock lever 30, the edge 32 of the lock lever 30 slides the shutter 50 provided on the cassette 22 in direction C shown in FIG. 2. When the window 52 of the shutter 50 coincides with the window 54 of the cassette 22, a portion of the magnetic disc 20 is exposed.

The magnetic disc 20 is rotated by the driving shaft 56 fixed onto the pulley 58 which is rotated by the spindle motor 62 via a belt 60.

The upper and lower heads 64 and 66 carry out recording and reading out of the information onto and from the tracks on the disc 20. In FIG. 1, the lower head 66 is not shown because it is just under the upper head 64. The heads 64, 66 are fixed on the carriage 68. By moving the carriage 68, the position of the heads 64, 66 can be adjusted relative to the disc 20, thus enabling recording and reading out at a desired position on the track. Details of the carriage driving mechanism will be described below.

FIG. 4 is a cross sectional view of the carriage 68. An upper arm 72 and a lower arm 74 extend from the carriage body 70. The lower arm 74 is made of stainless steel and has elasticity. The lower arm is pressed from the downward by a spring-mounting plate 76 and is attached to the carriage body.

A lower head 66 is fixed to the edge of the lower arm 74. An upper arm 72 is supported at the fulcrum 80 by a supporter 78 fixed to the carriage body 70, and is pressed downward by a presser bar spring 82. An upper head is fixed to the edge of the upper arm. The coil portion 82a of the presser bar spring 82 is disposed in the recess 70 of the carriage body 70 so as not to project from the back end of the carriage 70.

When the disc 20 is in loaded position, the upper and lower heads 64, 66 are close to each other as shown in FIG. 4.

When inserting or removing the disc 20, the upper and lower arms 64, 66 are open. The arm lifter 84 (FIG. 1) controls the closing and opening operation of, the heads.

The arm lifter 84 is rotatably supported by a bearing 86, and the edge 88 of the arm lifter 84 pivots in the vertical direction. The edge 88 of the arm lifter 84 is normally pressed downward by an arm lifter spring 90 and is engaged with a lifter receiver 92 of the carriage 68. When the cassette is loaded in position, the arm iifter 84 is positioned downward by means of the pressing force of the arm lifter spring 90, and moves the upper arm 74 so that the upper and lower heads close. The closing and opening operation of the heads 64, 66 is carried out in accordance with the up and down movement of the carrier 12. When the lifter claw 94 provided on the carrier 12 is up and touches the claw receiver 96 of the arm lifter, the edge 88 of the arm lifter moves upward, which lifts the lifter receiver 92 of the carriage 68 to open the upper and lower heads. When the carrier 12 is down at the loading position, the upper and lower heads are closed by the presser bar spring 82.

Thus, when the carrier 12 is positioned at the cassetteloading position, the upper and lower heads 64, 66 are closed to make contact with the magnetic disc 20. By moving the carriage 68 to the radius direction of the disc 20, the upper and lower heads 64, 66 are positioned and opposed to each other on a predetermined track.

The carriage driving mechanism controls the movement of the carriage 68, which is comprised of a step motor 98, gears 100, 102, a feed screw 104 and screw receiver 106.

The output of the step motor 98 is transmitted to the feed screw 104 via the gears 100, 102. Since the feed screw 104 is not directly attached to the shaft of the step motor 98, the degree of freedom increases according to the configuration of the step motor 98 and the feed screw. In this embodiment, the step motor 98 and the feed screw 104 are situated parallel to each other in order to decrease the axial length.

The driving force is output from the step motor 98 in direction B in FIG. 1 to rotate the gear 100 fixed onto the output shaft of the motor, which then rotates the gear 102 engaging with the gear 100. The gear 102 further rotates the feed screw 104 fixed on the co-axis of the gear 102. The feed screw 104 is arranged closer to the inner side relative to the gear 102, and the driving output is first fed in direction B (to the outer direction), then the output direction is changed 180 degrees by the gears 100 and 102 to the direction opposite to direction B. Thus, the carriage driving mechanism is compactly arranged within the full length of the feed screw 104, and the depth of the disc drive apparatus is reduced.

The rotation of the feed screw 104 moves the screw receiver 106 to and from direction B. Since the screw receiver 106 is fixed to the carriage 68, the translation of the screw receiver 106 means the movement of the carriage 68.

In FIG. 1, the carriage 68 is positioned in the middle of the movable range. A guide rail 110 is provided on the opposite side of the feed screw 104, along which the carriage 68 moves.

When the cassette is inserted, the step motor 98 drives the carriage to the rearmost position in order to position the heads 64, 66 in agreement with the outermost track (zero-zero track) of the disc 20. A zero-zero track sensor 108 is provided for detecting the positioning of the heads. The zero-zero track sensor detects the carriage position on the zero-zero track of the disc 20, and controls the movement of the carriage 68 with reference to the zero-zero position. The forward and backward movement of the carriage is controlled by the angle (direction) of the rotation of the step motor 98, and the heads 64, 66 are moved to a desired track to read/write the necessary information.

The disc drive apparatus of the present invention is characterized by an arrangement in which the back end of the carriage 68 is in agreement with the rear end of the frame 10 when the carriage is at the backmost position, and the other components are situated closer to the front than to the backmost position of the carriage 68. More particularly, the step motor 98 and the feed screw are disposed parallel to each other in order to shorten the length of the driving mechanism in the axial direction. According to this positioning, the step motor 98 is positioned closer to the front than to the backmost position of the carriage. Further, a recess 70a is provided on the carriage body to store the coil portion 82a of the presser bar spring 82 so that the presser spring does not project out from the back end of the carriage 68.

In this embodiment, an interface connector 112 is provided for communicating with,the peripheral equipments in order to input control commands for each movable portions as well as information to be recorded and output read-out information. As is shown in FIG. 1, the interface connector 112 is positioned so that a portion of the interface connector overlaps the disc drive motor 62.

A detailed cross sectional view of this configuration can be seen from the arrow A as shown in FIG. 5. The motor 62 consists of a motor body 62a and a motor pulley 114 fixed to the output shaft of the motor body, and a belt 60 is placed round the pulley 114. Driving power from the motor 62 is transmitted via the belt to a pulley 58 of the chuck to rotate the disc 20. The diameter of the motor pulley 114 is smaller than that of the motor body 62a, and thus the total shape of the drive motor 62 is overlaid with two different sized cylinders. In FIG. 5, the pulley 114 is located under the motor body 62a, and a space 116 is created under the motor body because of the smaller diameter of the pulley. This space can be used for rearranging a component or some other parts to increase the amount of space available. In this embodiment, the interface connector 112 is piaced in this space, which enables the miniaturization of the disc drive apparatus.

Thus, the present invention provides miniaturized disc drive apparatus by means of a more effective arrangement of each of the components. Those skilled in the art can make many substitutions and modifications of the embodiments described above, without departing from the scope and spirit of the appended claims.

Claims

CLAIMS:

1. A magnetic disc drive apparatus for performing at least either of recording or reading out of information in or from a disc-shaped magnetic recording medium, comprising: a disc driving motor for rotationally driving the magnetic recording medium; a pair of magnetic heads for performing at least either of recording or reading out information onto or from the magnetic recording medium; a carriage for mounting the magnetic heads and for contacting the magnetic heads to a desired track on the rotating magnetic recording medium, said carriage comprising a carriage body including a lower arm having a lower magnetic head at the end thereof, an upper arm rotatably supported by the carriage body and having an upper magnetic head at the end thereof, and a presser spring for pressing the upper arm against the lower arm; and a carriage driving mechanism for driving the carriage to move the magnetic heads back and forth in the radius direction of the recording medium, said carriage driving mechanism comprising a carriage driving motor, a feed screw aligned with the carriage driving motor and parallel to the carriage moving direction which is rotated by the carriage motor, a screw receiver fixed onto the carriage and for receiving the feed screw, and a zero-zero track sensor for detecting the carriage position where the magnetic heads are on an outermost track of the recording medium and positioned more to the front than the rear end of the carriage when it is in backmost position, said presser bar spring having a coil portion which is housed within the carriage body.

2. A disc drive apparatus according to claim 1 wherein said disc drive motor consists of a motor body and a pulley having a smaller diameter than the motor body and the total shape thereof is overlaid with two different sized cylinders so that a space is created around the pulley, said disc drive apparatus further comprising an interface connector for communicating with peripheral equipments, the interface connector being located in said space around the pulley.

3. A magnetic disc drive mechanism for performing at least either of recording or reading from information onto or from a disc-shaped magnetic recording medium, comprising: a disc driving motor for rotating the magnetic recording medium and consisting of a motor, body and a pulley having a smaller diameter than the motor body, the total shape of said disc driving motor being overlaid with two different sized cylinders so that a space is created around the pulley; a pair of magnetic heads for carrying out at least either of recording or reading out information onto or from the magnetic recording medium; a carriage for mounting the magnetic heads and for contacting the magnetic heads to a desired track on the rotating recording medium; a carriage driving mechanism for driving the carriage in order to move the magnetic heads back and forth in the radius direction of the recording medium: and an interface connector for communicating with peripheral equipment, at least a portion of said interface connector being positioned in said space around the pulley.

4. A disc drive apparatus for recording information on or reading information from a magnetic disc substantially as described with reference to the accompanying drawings.