GB2236612A

GB2236612A - Head drive mechanism

Info

Publication number: GB2236612A
Application number: GB9020494A
Authority: GB
Inventors: Yuichi Kurosawa
Original assignee: Asahi Kogaku Kogyo Co Ltd
Current assignee: Pentax Corp
Priority date: 1989-09-22
Filing date: 1990-09-19
Publication date: 1991-04-10
Anticipated expiration: 2010-09-19
Also published as: GB2236612B; FR2652437A1; FR2652437B1; DE4029979A1; DE4029979C2; JPH03113784A; JPH0828084B2; GB9020494D0

Abstract

A head drive mechanism associated with a disk drive device whereby the head 7 is mounted on a carriage 6, on which a protrusion 9 is provided, and is driven in the direction parallel to the surface of the disk by the protrusion being engaged with a lead screw 5 when the lead screw is rotated. When the carriage is held against a stopper (eg. the motor housing 1) located at a predetermined position, the movement of the head in the radial direction of the disk is prevented. A control system further rotates the screw in the direction that the carriage is held against the stopper, and the protrusion is forced to ride up the inclined portion of the screw thread whereby the head is moved away from the disk. <IMAGE>

Description

:2:2:3 f11 ES L SPECIF1CATION Title of the Invention llead Drive Mechanism

Background of the Invention

The present invention relates to a head drive mechanism for magnetic disk drive device.

Electronic still video cameras are so designed that magnetic heads are used for recording or reproducing video signals onto or from video floppy disks (magnetic disks). WhIle the magnetic dlsk is riot rotated, It may be deformed If the magnetic head is kept abutting thereagainst for a long time. In such a case, the disk drive system is designed to detach the magnetic head from the magnetic disk.

Conventionally, an actuator or the like has been employed to detach the magnetic head from the magnetic disk.

Notwithstanding, the disadvantage pertaining to the use of such an actuator Is that the disk drive tends to become not only complicated in construction and hence large-sized but also costly.

Summary of the Invention

It Is therefore an object of the present Invention to provide an improved head drive mechanism simple in construction In that a head is made detachable from a disk without adding a special mechanism thereto.

According to the present invention, there is provide a head drive mechanism associated with a disk drive device, a disk being mounted and driven to be rotated on said disk drive device, said head drive mechanism comprising a head member capable of recording signals on said disk and reproducing the same from said disk, said head drive mechanism further comprises:

a rotary shaft extending in the direction parallel to the surface of said disk and having a helical groove formed on the circumferential surface thereof, said helical groove being provided with an inclined sectional surface; a support member carrying said head member thereon and provided with an engaging member, said support member being movable in the direction parallel to the surface of said disk, said engaging member being engaged in said helical groove of the rotary shaft in such a fashion that said support member is moved in parallel with the surface of said disk upon rotation of said rotary shaft; a stopper member for preventing the sliding movement of said support member in the direction parallel to the surface of said disk at a predetermined position; and control means for controlling rotation of said rotary shaft In such a fashion that said rotary shaft is further rotated at a predetermine amount after the movement of said support member is stopped by said stopper member so that said engaging member Is forced to be moved away from said disk at said predetermined position due to sliding contact of said engaging member with said inclined sectional surface of said helical groove.

According to another aspect of the invention, there is provided a head drive mechanism associated with a disk drive device, a disk being mounted and driven to be rotated on said disk drive device, said head drive mechanism comprising a head member capable of recording signals on said disk and reproducing the same from said disk, said head drive mechanism further comprises: a lead screw extending in parallel with the surface of said disk, the thread of said lead screw 25 having an inclined sectional surface; and provided with an engaging member on one end thereof, said engaging member being engaged with said lead screw in such a fashion that said support member Is moved In the direction parallel to the surface of said disk upon rotation of said lead screw; a guide member for guiding said support member In the direction parallel to the surface of said disk, and for pivoting the other end of said support member such that said one end of said support member is swIngable in the direction orthogonal to the guiding direction of said guide member; a stopper member for preventing the sliding movement of said support member In the direction parallel to the surface of said disk at a predetermIned position; and control means for controlling rotation of said lead screw In such a fashion that said lead screw Is further rotated at a predetermine amount after the movement of said support member is stopped by said stopper member so that said support member is forced to be moved away from said disk at said predetermined position due to sliding contact of said engaging member with the thread of said lead screw.

Optionally, the head drive mechanism further comprises a biasing member for biasing said engaging member to be neutrally engaged with said lead screw.

Further, the control means comprises detect means for detecting that said support member Is located at said predetermined position. 5 Description of the Accompanying DrawJnrs

Fig. 1 Is a perspective view of a disk drive device provided with a head drive mechanism embodying the present invention; Fig. 2 Is a block diagram of the head drive mechanism embodying the present Invention; Fig. 3 is a side view of the magnetic disk and the head drive mechanism embodying the present Invention while the magnetic disk Is kept abutting against a video floppy disk; Fig. 4 is an enlarged side view illustrating the disk kept abutting against the video floppy disk; Fig. 5 is a sectional view illustrating the relation between a lead screw and a needle In the head drive mechanism embodying the present invention; Fig. 6 is a side view illustrating the magnetic disk detached from the video floppy disk In the head drive mechanism embodying the present Invention; and 25 Fig. 7 is an enlarged side view Illustrating the magnetic disk detached from the video floppy disk.

Description of the Embodiments

Fig. 1 is a perspective view of a disk drive device provided with a head drive mechanism embodying the present invention.

As shown in Fig. 1, the disk drive device comprises a spindle motor 1 used for rotating a flywheel (spindle chuck) 2, a video floppy disk 3 mounted and chucked on the flywheel 2 for being rotated and used for recording or reproducing a video signal, a step motor 4 used for rotating a lead screw 5, and a carriage 6 on which a magnetic head 7 is mounted.

The component parts further Include a needle 9 as a mating part secured on the carriage 6 to be engaged with the lead screw 5; a plate spring 8 as a resilient member secured to the carriage 6, the plate spring 8 being used for biasing the carriage 6 In such a manner that the needle 9 is pressed against the lead screw 5; and a guide bar 11 used for guiding the carriage 6 in its extending direction.

In addition, a projection 12 is secured to the carriage 6 and arranged so that it passes the position opposite to a detection portion of a photocoupler 13 which is secured to a base plate (not shown). Fig. 2 Is a block diagram illustrating the configuration of disk drive embodying the present Invention. 5 As shown in Fig. 2, drive circuits 21. 22 are used for driving the spindle motor 1 and the step motor 4, respectively. A control circuit 23 comprises a microcomputer or the like and controls each of the circuits in correspondence with the operation of' an input circuit 24 having switches or buttons. A recordIng/reproducing circuit 25 receives a signal, modulates it, and supplies the modulated signal to the magnetic head 7. Moreover, the recording/reproducing circuit 25 demodulates the signal reproduced from the magnetic head 7 and outputs the demodulated signal.

When the input circuit 24 Is operated, for example, to instruct recording a signal, the control circuit 23 drives the spindle motor 1 via the drive circuit 21, thereby the video floppy disks 3 is rotated. The control circuit 23 also drives the step motor 4 via the drive circuit 22, thereby the lead screw 5 Is rotated. As the needle 9 Is kept engaging with the lead screw 5, the needle 9, therefore the carriage 6 on which the needle 9 is secured Is moved 25 with being guided by the guide bar 11. As a result, the magnetic head 7 fixed to the carriage 6 is moved In the direction parallel to the surface of the video floppy disk 3 and caused to face a predetermined track. this time, as shown In Figs. 3 and 4, the magnetic head 7 contacts the video floppy disks 3, whereas the video floppy disks 3 resiliently deforms In such a manner that its contact part slightly protrudes to the other side.

The video signal received from the circuit (not shown) Is modulated in the recording/reproducing circuit 25 and the signal thus modulated Is supplied to the magnetic head 7. In this way, the video signal is recorded on a predetermined track of the video floppy disk 3.

is When reproducing is instructed, the magnetic head 7 and the video floppy disk 3 are driven as above. Then the video signal reproduced by the magnetic head 7 Is demodulated In the recording/reproducIng circuit 25 before being delivered to a display such as a CRT (not shown).

When stopping recording or reproducing operation is Instructed, the control circuit 23 stops driving the drive circuit 21 so as to stop the rotation of the spindle motor 1. The control circuit 23 then drives the step motor 4 via the drive circuit 22 to make the carriage 6 move in the direction parallel to the surface of the video floppy disk 3 toward the Inner (or outer) peripheral of the video floppy disk 3.

When the carriage 6 is located at a predetermined position (inside the innermost peripheral track or outside the outermost peripheral track), It abuts against the cage of the spindle motor 1 (the Inner wall of the outer cover (not shown) of the disk drive, for Instance, when the carriage 6 Is moved in the outer peripheral direction) and stops thereat. When the carriage 6 reaches the predetermined position, the projection 12 is located opposite to the detection part of the photocoupler 13 and intercepts the light from the photocoupler 13. The control circult 23 monitors the output of the detection part of the photocoupler 13 and detects its position.

When the control circuit 23 detects the predetermined position from the output of the detection part of the photocoupler 13, It further drives the step motor 4 slightly In the direction in which the carriage 6 abuts against the spindle motor 1. The needle 9 thus runs on the teeth of the lead screw 5.

More specifically. while the needle ga is being driven normally, it remains in contact with the front and rear teeth of the lead screw Sa as shown by a thick line of Fig. 5. When the needle gb is driven to the predetermined position where the carriage 6 abuts against the stopper, it runs on the rear teeth of the lead screw 5b as shown by a thin line of Fig. 5 (i.e., it moves downward in Fig. 5).

As a result, the carriage 6 slightly revolves clockwise about the guide bar 11 against the biasing force of the plate spring 8 as shown in Fig. 6. The magnetic head 7 thus detaches from the video floppy disk 7 as shown in Fig. 7 as an enlarged view of Fig. 6.

Although, the lead screw is employed to transmit the driving force to the carriage in the embodiment above, the lead screw can be substituted with a rotary 1. shaft-provided with a helical groove having an inclined sectional surface on its circumferential surface.

Although the needle has been employed as the engaging part in the embodiment shown, a ball or the like may be used. Although the plate spring has been employed as the resilient member, moreover, rubber, a coil spring or the like may be used.

Although the disk drive according to the present invention has been described as what Is applicable to an electronic still video camera, for instance, the 2. disk drive according to the present invention may be applicable to other apparatus.

In the disk drive according to the present invention, the lead screw Is further driven when the carriage is further moved slightly in the direction In _5 which the carriage abuts against the stopper when the carriage abuts thereagainst as stated above. The engaging part Is consequently caused to run on the lead screw so as to make the carriage rock, so that the head Is simply detached from the disk without adding a special mechanism as represented by an actuator or the like.

Claims

What is claimed is:

1. A head drive mechanism associated with a disk drive device, a disk being mounted and driven to be 5 rotated on said disk drive device, said headdrive mechanism comprising aPead member capable of recording signals on said disk and reproducing the same from said disk. said head drive mechanism further comprises: a rotary shaft extending in parallel with the surface of said disk and having a helical groove formed on the circumferential surface thereof, said helical groove being provided with an inclined sectional surface; a support member carrying said head member thereon and provided with an engaging member, said support member being movable in the direction parallel to the surface of said disk, said engaging member being engaged in said helical groove of the rotary shaft in such a fashion that said support member is moved in the direction parallel to the surface of said disk upon rotation of said rotary shaft; a stopper member for preventing the sliding movement of said support member in the direction parallel to the surface of said disk at a predetermined 25 position; and control means for controlling rotation of said rotary shaft in such a fashion that said rotary shaft is further rotated at a predetermine amount after the movement of said support member Is stopped by said stopper member so that said support member Is forced to be moved away from said disk at said predetermined position due to sliding contact of said engaging member with said Inclined sectional surface of said helical groove.

2. The head drive mechanism according to claim 1, which further comprises a biasing member for biasing said engaging member to be neutrally engaged with said helical groove.

3. The head drive mechanism according to claim 1, which further comprises guide means for guiding said support member so that sald head member Is moved In the radial direction of said disk.

4. The head drive mechanism according to claim 3, wherein said guide means comprises a cylindrical rod member, wherein said support member has a hole extending in the direction in which said support member 25 is moved, said rod member being engaged In said rod member. whereby said support member is moved along said rod member, and said support member is capable of being rotated in the direction orthogonal to the extending direction of said rod member.

5 5. The head drive mechanism according to claim 1, wherein said disk drive device comprises a case member for accommodating a spindle motor for driving said disk member, and wherein said stopper member comprises a wall of said case member in the direction parallel to the spindle of said spindle motor provided between said spindle motor and said head member.

6. The head drive mechanism according to claim 1, wherein said control means comprises detect means for 11 detecting that said support member is located at said predetermined position.

7. The head drive mechanism according to claim 6, wherein said detect means comprises a fixedly disposed photocoupler, and light shield member provided on said supporting member, and wherein said light shield member shields the light of said photocoupler when said supporting member Is located at said predetermined position.

8. The head drive mechanism according to claim 2, wherein said biasing means comprises a leaf spring, one end side portion of said leaf spring and said engaging member being arranged to nip said rotary shaft therebetween, the other end of said leaf spring being attached on said support member.

9. A head drive mechanism associated with a disk drive device, a disk being mounted and driven to be rotated on said disk drive device, said head drive mechanism comprising a head member capable of recording signals on said disk and reproducing the same from said disk, said head drive mechanism further comprises: a lead screw extending in parallel with the surface of said disk, the thread of said lead screw having an inclined sectional surface; a support member carrying said head member thereon and provided with an engaging member on one end thereof, said engaging member being engaged with said lead screw in such a fashion that said support member is moved in the direction parallel to the surface of said disk upon rotation of said lead screw; a guide member for guiding said support member In the direction parallel to the surface of said disk, and for pivoting the other end of said support member such that said one end of said support member Is swingable in the direction orthogonal to the guiding direction of said guide member; a stopper member for preventing the sliding movement of said support member In the direction parallel to the surface of said disk at a predetermined position; and control means for controlling rotation of said lead screw in such a fashion that said lead screw Is further rotated at a predetermine amount after the movement of said support member Is stopped by said stopper member so that said support member Is forced to be moved away from said disk at said predetermined position due to sliding contact of said engaging member with the thread qf said lead screw.

10. The head drive mechanism according to claim 9, which further comprises a biasing member for biasing said engaging member to be neutrally engaged with said lead screw.

11. The head drive mechanism according to claim 9, wherein said support member has a hole at said other end thereof, and wherein said guide member comprises a rod member having a circular sectional surface, said rod member being fitted In said hole, whereby said support member Is guided along said rod member as well as made swingable about said rod member.

12. The head drive mechanism according to claim 9, wherein said disk drive device comprises a case member for accommodating a spindle motor for driving said disk member, and wherein said stopper member comprises a wall of said case member in parallel with the spindle of said spindle motor provided between said spindle motor and said head member.

13. The head drive mechanism according to claim 9, wherein said control means comprises detect means for detecting that 4aid support member Is located at said predetermined position.

14. The head drive mechanism according to claim 13, wherein said detect means comprises a fixedly disposed photocoupler, and a light shield member provided on said supporting member, and wherein said light shield member shields the light of said photocoupler when said supporting member Is located at said predetermined position.

15. The head drive mechanism according to claim 10, wherein said biasing means comprises a leaf spring, one end side portion of said leaf spring and said engaging member being arranged to nip said lead screw therebetween, the other end of said leaf spring being attached on said support member.

is 1 Published 1991 atIbe PatentOffice. State House. 66171 High Holborn. Undon WC1R4TP. Further copies rnay be obtained frorn Sales Branch. Unit 6. Nine Mile Point Cwrnfeltnfach, Cross Keys. Newport. NPI 7HZ. Printed by Multiplex techniques ltd. St Mary Cray. Kent.