JPH0237178Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a head feeding device in a recording/reproducing apparatus that uses a disk-shaped recording medium such as a magnetic disk.

A magnetic disk device is an example of a recording/reproducing device that uses a disk-shaped recording medium. In a magnetic disk drive, it is necessary to intermittently move a head, which serves as a transducer for recording and reproducing signals on the disk, in the radial direction of the disk. Therefore, a rotary stepping motor was used, and the intermittent rotational force of this motor was converted into linear motion using a steel belt, etc., and the head carriage was moved linearly and intermittently in the radial direction of the disk. There is.

However, according to the above conventional device, the accuracy of the track position is determined by the accuracy of the stepping motor, so a sophisticated motor must be used.
It was becoming expensive. In addition, in order to control the head position, it is necessary to determine the reference position for head feeding, but with conventional equipment, a track sensor and a detector for the excitation state of the stepper are required to determine the reference position for head feeding. Therefore, the configuration of the reference position determining mechanism was complicated.

The purpose of the present invention is to enable the head to be moved intermittently by a continuously rotating motor, so that a simple and inexpensive motor is required, and the structure of the reference positioning mechanism of the head can be simplified. The object of the present invention is to provide a head feeding mechanism that makes it possible.

The present invention will now be described with reference to the illustrated embodiments.

First, an example of a magnetic disk applicable to the device of the present invention will be explained with reference to FIGS. 1 to 3. The magnetic disk shown in FIGS. 1-3 is in the form of a cassette. That is, the magnetic disk cassette 1 is mainly composed of a flat box-shaped hard case 2 and a flexible disk 3 rotatably housed within the hard case. A disk hub 4 is integrally provided at the center of the disk 3. The disk hub 4 is provided with conical protrusions 5 on the upper and lower surfaces of its center, and an annular protrusion 6 is formed around these protrusions 5, and the inner side of the protrusion 6 is provided with the following. spindle hub 10
An engaging protrusion 7 having a triangular cross section is provided for engaging with the protrusion 5 to rotationally drive the disk hub 4. The disk hub 4 having these protrusions 5, 6, etc. is exposed through a window hole formed in the case 2. An opening 8 is provided at one side edge of the case 2 on the upper and lower surfaces so that the magnetic head can enter and come into contact with the recording surface of the disk 3. The case 2 is attached to the edge of the case 2 where the opening 8 is formed.
A step portion is formed that is somewhat lower than the upper and lower surfaces of the case 2, and a shutter plate 9 is attached to this step portion so as to sandwich the case 2 from above and below, and to be slidable along the step portion. Window holes 10 are formed in the shutter plate 9 so that the magnetic heads can enter and come into contact with the recording surface of the disk 3 so that they overlap one another. A pair of folding pieces 12 and 13 are formed on the shutter plate 9, and a pair of guide pieces 14 and 14 are also formed by folding down. The guide pieces 14, 14 are fitted into guide grooves 18, 18 formed along one side edge of the case 2 to guide the sliding movement of the shutter plate 9. In the opening 8 of the case 2, notches 15 and 16 are formed continuously to the opening 8, and a shutter plate 9 is formed.
When the shutter plate 9 moves to the left in FIG. The case 2 also includes a spring 1 at the sliding portion of the shutter plate 9.
A mounting groove 17 for mounting the J-shaped bent portion 11a of No. 1, and notches 19 and 20 on which pins to be described later for sliding the shutter plate 9 in parallel with the guide grooves 18 and 18 are to be slidably contacted. It is formed. The bent portion 11a of the spring 11 is fitted into the mounting groove 17 and then welded by heating the periphery of the mounting groove 17. The shutter plate 9 opens the case 2 while pushing open the upper and lower overlapping parts vertically.
Attach to. In that case, guide groove 1 of case 2
Notch 2 formed to connect to 8 and 18
7, 27 to the guide pieces 14, 14 of the shutter plate 9
to invade. At this time, the left end of the shutter plate 9 in FIG. 2 is in contact with the upper and lower surfaces of the case 2, which is one step higher than the step on which the shutter plate 9 is mounted. Then, when the shutter plate 9 is moved in the direction of the guide grooves 18, 18, the guide piece 1 of the shutter plate 9
4 and 14 fit into the guide grooves 18 and 18, and the left end 9a of the shutter plate 9 in FIG. The engagement state between the pieces 14, 14 and the guide grooves 18, 18 is maintained, and the shutter plate 9 is prevented from falling off. When the shutter plate 9 is attached to the case 2 as described above, the L-shaped bent portion 11b at the other end of the spring 11 is latched onto the fold-down piece 12 of the shutter plate 9, and the shutter plate 9 is attached to the spring 11. Due to the elasticity of the window hole 1 of the shutter plate 9
0 and the opening 8 of the case 2 are different and the same opening 8
is biased to slide in a direction that shields the The shutter plate 9 resists the biasing force of the spring 11.
When the spring 11 is slid, the spring 11 engages with the folded-down piece 13 of the shutter plate 9, and the bent portion 11 of the spring 11
b is designed to prevent it from coming off the fold-down piece 12. The shutter plate 9 is formed with a cutout engagement portion 30 that is to be engaged with a pin 89 of an opening/closing member 81, which will be described later.

There are square recesses 2 in the corners of the hard case 2.
1 and 22, and circular holes 23 and 23 into which pins for positioning the cassette 1 are inserted are provided within the range of these recesses. The case 2 is also provided with recesses 24 and 25 on the end surface on the side where the shutter plate 9 is attached for detecting incorrect insertion of the cassette 1. In the case 2, holes 26, 26 for preventing writing are provided at the edge portion of the shutter plate 9 opposite to the mounting portion thereof. These holes 26,
There are recesses 28, 28 on the side of the case 2 where the 26 is formed.
are provided in the recesses 28, 28, the holes 26,
writing prevention operation piece 29 for opening and closing 26;
29 is built-in.

Next, a cassette loading device for loading the magnetic disk cassette 1 constructed as described above will be explained. 4 to 7, the cassette loading device mainly consists of a chassis 42, a cassette holder 40 and an upper case 41 rotatably supported by the chassis 42, and a pressing member 66 provided on the cassette holder 40. Become. The chassis 42 includes a support portion 44 having a pin 43 that serves as a support shaft for the upper case 41, a support portion 46 that has a pin 45 that serves as a support shaft for the holder 44, and pins 47 and 48 that position the cassette 1. Also, the chassis 4
A spindle hub 105 protrudes from the top surface of 2. As shown in FIG.
1 has a top plate 52 and side plates 50 and 51 formed by bending both side edges of the top plate. Side plate 5
At the base end of 0, 51, there is an engaging portion 5 that engages with the pin 43.
3 is formed, and the engaging portion is rotatably supported by a pin 43. The upper case 41 is urged to rotate counterclockwise in FIG. 4, that is, in a direction away from the chassis 42, by a spring 55 applied between the case and the locking portion 54 of the chassis 42. As shown, the engaging portion 56 formed on the side plate 50 comes into contact with the protrusion 57 of the chassis 42, thereby delimiting the rotational limit due to the biasing force and maintaining the rotational mode. It is becoming more and more common. As shown in FIG. 5, the upper surface plate 52 of the upper case 41 has a bent portion 58 for vertically moving the upper pad at a position near the base end.
and a pressing part 59 for pressing the disk hub.
Lifting parts 60, 60 for lifting the holder 40 are formed at a position near the free end, and a notched stepped part 61 is formed in the side plate 51.

As shown in FIG. 6, the holder 40 is
The cassette 1 is formed to be able to receive the cassette 1 by left and right upper plates 65, 65, side plates 62, 63 following these upper plates, and a lower plate 93 that connects these side plates together. Pin holes 64, 64 into which the pins 45, 45 as support shafts are inserted are formed at the base ends of the side plates 62, 63. An appropriate number of protrusions 67 are formed on the top plate 65, and these protrusions 67
The hole 68 of the holding member 66 is fitted and caulked, and the holding member 66 is then fixed to the top plate 65. The holding member 66 has a pair of bent portions 69, 69 extending from the front end toward the rear end.
A hub presser piece 71 is formed between the bent portions 69 and 69 and has a recessed portion 70 whose free end protrudes downward. Hub holding piece 71
The base of the connecting piece 72 connects the bent portions 69, 6 on both sides.
9, and when the bent portions 69, 69 bend, the hub presser 71 also bends. Arm-shaped side pieces 73 and 77 are integrally formed on the left and right sides of the holding member 66, and the tip 74 of the left side piece 73 in FIG. A bent piece 75 is formed.
The bent piece 75 is located in a notch 76 formed in the side plate 62 of the holder 40. Further, the tip end 78 of the right side piece 77 is also slightly bent downward. However, the side piece 77 is slightly shorter than the other side piece 73;
Furthermore, a protruding piece 79 is formed on the side piece 77 toward the outside. At the bases of the side pieces 73, 77, spring locking pieces 80, 80 are formed that face inward from each other. The holding member 66 also includes side pieces 73,
On the inner side of the shutter plate 77, a holding part 8 holds the opening/closing members 81, 81 for opening and closing the shutter plate 9.
2 and 82 are integrally formed. holding part 82,
Reference numeral 82 denotes holding parts 84, 84 for covering the bases 83, 83 of the opening/closing members 81, 81, and the opening/closing members 8.
It has cam parts 85, 85 for serving as a guide when rotating the opening/closing members 81, 81, and stepped regulating parts 86, 86 for regulating the rotational position of the opening/closing members 81, 81. The opening/closing members 81 , 81 have pins 87 , 87 that serve as rotation axes, and projecting pieces 88 , 8 that are located below the holding portion 82 and serve as guides for the rotation of the opening/closing members 81 .
8, and pins 89, 89 for engaging the recess 30 of the shutter plate 9 and sliding the shutter plate 9. The opening/closing members 81, 81 have their pins 87,
87 is inserted into the hole 91 of the holder 40, and the pin 8
The opening/closing member 81 on the left side in FIG. The opening/closing member 81 on the right side is biased to rotate clockwise, and the opening/closing member 81 on the right side is biased to rotate counterclockwise, and the side surfaces of the opening/closing members 81, 81 abut against the regulating portions 86, 86 of the pressing member 66, so that the rotation due to the biasing force is prevented. It's becoming regulated. Above the bases 83, 83 of the opening/closing members 81, 81, there is a pressing member 6 fixed to the holder 40 by a protrusion 67.
The opening/closing members 81, 81
It is prevented from coming off. Opening/closing members 81, 81
is rotated by sliding on the upper surface of the holding parts 82, 82 of the pressing member 66, but since the projecting pieces 88, 88 are located below the holding parts 82, 82, the opening/closing member 81 , 81 are held securely. A cassette insertion slot 9 is provided at the free end of the holder 40.
2 is formed, and a notch 94 into which the spindle hub 105 and head carriage fit is provided in the center of the lower plate 93 of the holder 40. At the back left side of the holder 40 in FIG. 6, a protrusion 95 is provided to prevent incorrect insertion of the cassette. Holder 4
A bent portion 96 is provided at the rear end of the cassette 1, with which the rear end surface of the cassette 1 comes into contact to regulate the position of the cassette 1.

Next, the operation of the above-mentioned cassette loading device is shown in FIG.
This will be explained with reference to FIGS. 7 to 9. 7th
In the figure, the disk cassette 1 is attached to the shutter plate 9.
If you insert it from the entrance 92 with the side facing towards the back,
The pin 89 of the opening/closing member 81 on the left side in the figure enters the notch engaging portion 30 of the shutter plate 9, and the pin 89 is pushed by the wall surface of the notch 19 (see FIG. 1) provided in the case 2. Left opening/closing member 8
1 rotates counterclockwise. Due to this rotation of the opening/closing member 81, the pin 89 moves to the left while drawing an arc, so that the shutter plate 9 is also moved to the left side, and the window hole 10 of the shutter plate 9 and the opening of the case 2 are moved. 8 matches. That is, the shutter is opened. Note that the pin 89 of the opening/closing member 81 on the right side is pushed by the wall surface of the notch 20 of the case 2 (see Figure 1) and rotated clockwise, but the pin 89 on the right side engages with the pin 89. Since the shutter plate 9 is not provided with the notch engaging portion, the above-mentioned movement of the shutter plate 9 is not affected at all. When the shutter plate 9 is moved in this way to open the shutter and the cassette 1 is pushed in, the recess 24 of the case 2 fits into the protrusion 95 of the holder 40, and the end surface of the case 2 fits into the bent part 96 of the holder 40. This is the insertion limit for the cassette 1. Also, by inserting the cassette 1, the side piece 73 of the holding member 66
The tip 74 of the case 2 is pushed up once, but when the cassette 1 is inserted to the limit position, the tip 74 plunges into the recess 21 of the case 2.
The cassette 1 is restrained in the inserted state.

The cassette 1 is loaded in this manner, and information signals are recorded and reproduced on the disk 3 by rotating the upper case 41 from the state shown in FIG. 4 to the state shown in FIG. . A pair of engagement pieces 97, 97 are provided at the front end of the holding member 66.
are provided, and when the engaging pieces 97, 97 are hooked on the bent protrusions 60, 60 of the upper case 41, the upper case 41 is rotated above the chassis 42 as shown in FIG. Holder 40 when
is also rotated above the chassis 42. but,
When the upper case 41 is pushed down and rotated, the holder 40 also rotates downward. Thus upper case 4
1 is placed over a lower case (not shown) and closed, the state is maintained by the action of a locking mechanism (not shown).

FIG. 8 shows a state in which the upper case 41 has been pushed down to reach the recording/reproducing position, but the holder 4
Since the pivot positions of the upper case 41 and the upper case 41 are different,
Before reaching the state shown in FIG. 8, the bent portion 69 of the pressing member 66 is
69 is pushed and deflected downward, and the holder 40 is urged downward. Since the hub holding piece 71 is connected to the base of the bent parts 69, 69 by the connecting piece 72, when the bent parts 69, 69 bend downward, the hub holding piece 71 also bends downward.
At the recording/reproducing position as shown in Fig. 8, the hub holding piece 7
The protrusion 5 of the disk hub 4 is pushed by the downwardly protruding recess 70 at the tip of the disk hub 4, and the disk hub 4 is securely attached to the spindle hub 105. Upper case 4
1 pushes up the holder 40, the holding member 66 is pressed down before the holder 40 reaches the rotation limit position.
The bent portion 75 of the holder 4 comes into contact with the chassis 42, and the holder 4
0 is further pushed down, the tip 74 of the side piece 73 of the holding member 66 is lifted. As a result, the tip portion 74 escapes from the recess 21 of the case 2, the cassette 1 is no longer restrained from the holder 40, and the cassette 1 is moved to the positioning pin 4 on the chassis.
7 and 48, it is positioned at the normal position.
Note that the pin 47 is inserted into the recess 2 of the case 2 of the cassette 1.
1, and the tip of the pin 47 contacts the bottom of case 2.
The pin 48 enters the circular hole 23 of the cassette 1, and comes into contact with the lower surface of the case 2 to regulate the front-rear and up-down positions of the cassette 1. Since the length of one side piece 77 of the holding member 66 is slightly shorter than the length of the other side piece 73, when the position of the cassette 1 is regulated as described above, the position of the cassette 1 is regulated as shown in FIG. However, the tip end 78 of the side piece 77 has not yet come into engagement with the end surface of the recess 21 of the case 2. Also, by pushing down the upper case 41, the bent portion 58 is lowered,
Accordingly, the upper carriage holding the upper magnetic head descends to assume the recording/reproducing position. In FIG. 9, reference numeral 100 is a DC rotary motor, which is attached to the chassis to rotate the disk 3 and move the magnetic head. 101 is a pulley of the motor.

To eject the loaded cassette 1, the lock mechanism (not shown) is released and the upper case 41 and cassette holder 40 are rotated by the elasticity of the spring 55 as shown in FIG. conduct. When the upper case 41 rotates counterclockwise due to the elasticity of the spring 55, the engaging piece 97 of the pressing member 66 fixed to the holder 40 engages the upper case 41.
The tip of the pin 47 will come out of the positioning hole of the cassette 1, and the cassette 1 will be pushed outward based on the elasticity of the springs 90, 90 of the opening/closing members 81, 81. shall be. However, the side piece 77 of the holding member 66
The tip 78 of the cassette 1 hits the inner wall of the recess 21 of the cassette 1 and temporarily restrains the cassette 1. When the upper cover 41 is further rotated, the stepped notch 61 provided in the upper case 41 pushes up the protruding piece 79 of the pressing member 66, disengaging the tip 78 from the recess 21 of the cassette 1, and springs the cassette 1. It is pushed outward by the rotation biasing force of the opening/closing member 81 based on the elasticity of the opening/closing member 90. As the opening/closing member 1 returns to rotation, the shutter plate 9 also returns to its original position, closing the shutter.

Next, the rotational drive mechanism of the disk 3 and the movement mechanism of the magnetic head will be explained. In FIG. 10, a bearing 108 is fitted and fixed on the lower surface side of the chassis 42, and the shaft portion of the spindle hub 105 is rotatably supported by the inner periphery of the bearing 108. A boss of a small-diameter gear 104 is fitted and fixed to the shaft portion of the spindle hub 105 that protrudes from the lower end of the bearing 108, and a rotating body 103 is fitted into the boss of the gear 104.
are fitted and fixed. The outer periphery of the rotating body 103 is a pulley part, and the belt 1 is attached to this pulley part.
02 is multiplied. The belt 102 is also hung around the pulley 101 of the motor 100, and as long as the motor 100 is driven to rotate, the rotating body 103
The gear 104 and spindle hub 105 are driven to rotate together. A hole 1 is provided in the center of the spindle hub 105 for receiving the lower protrusion 5 provided in the center of the disk hub 4.
06 is formed on the spindle hub 105, and a protrusion 107 is formed on the spindle hub 105 to engage with the engagement protrusion 7 of the disk hub 4 to rotationally drive the disk 3. The rotating body 103 and the small diameter gear 104 constitute a continuous rotating body.

A cam body 109 as a rotating body for moving the head carriage is disposed on the outer periphery of the bearing 108.
is rotatably fitted with the rotation center axis being the same as the spindle hub. As shown in FIGS. 11 and 21, a cam groove 110 having a cam surface for moving the head carriage is formed on the upper surface side of the cam body 109. Cam groove 11
0 is formed in 17 steps by dividing the cam body 109 into two halves each having a diameter that changes stepwise, and the cam groove 11 formed in one half circumference.
Cam groove 1 formed in the mesial part of 0 and the other half circumference
The ten distal portions are connected to each other by a connecting groove 111. FIG. 12 shows how the cam groove 110 and the connecting groove 111 change in diameter. on the other hand,
The cam groove 11 is formed on the outer periphery of the lower surface of the cam body 109.
Locking recesses 112 as detection parts corresponding to each stage position of 0 and the same number as the number of stages are formed, and an annular projection 114 is formed at an intermediate part between the center and the outer periphery of the cam body 109. A downward protruding pin 113 is formed in a part of 114. pin 1
13, a gear 115 is rotatably fitted as shown in FIGS. 10 and 14, and an annular gear 116 is rotatably fitted to the outer periphery of the annular projection 114. Gear 115 is annular gear 11
It meshes with both the inward gear 119 and the small diameter gear 104 formed on the inner circumference of the gear 6. As shown in FIG. 13, a ratchet tooth-shaped engagement gear 118 is provided on the outer periphery of the annular gear 116.
It is formed corresponding to each of the 10 stages. 15th
As shown in FIGS. 20, 20, and 21, the cam body 109 has a groove located further outward than the locking recess 11 and below the locking recess 112. An engagement groove 134 is formed. If the rotational direction of the cam body 109 is the direction of arrow L, the rear end portion of the engagement groove 134 becomes an inclined surface 134a with respect to this rotational direction and is connected to the lower surface 133 of the engagement groove 134 forming portion. Cam body 109
The cam groove 110 may alternatively be a protruding cam surface.

In FIGS. 14 and 15, the cam body 109
A bell-crank-shaped control lever 120 is provided on the side thereof so as to be rotatable about a shaft 123. A permanent magnet 124 is fixed to the edge of one arm of the lever 120, and the iron core 1 of the magnet 124 and the electromagnet 125
26, the lever 120 is urged to rotate counterclockwise in FIG.
A hook-shaped end 121 of one arm of the cam body 109 enters and engages with the locking recess 112 of the cam body 109. On the other hand, the other hook-shaped arm end 122 of the lever 120 faces the engagement gear 118 on the outer periphery of the annular gear 116, but is normally spaced apart from the engagement gear 118. The arm formed by the hooked arm end 121 of the lever 120 has elasticity in the vertical direction, and when the arm end 121 is engaged with the locking recess 112 of the cam body 109, the arm is forcibly moved. The engagement groove 134 is bent into a state in which it comes into contact with the lower surface 133 of the engagement groove 134 formed in the shape of an eave.

FIG. 15 shows the configuration of the electromagnet 125. The electromagnet 125 includes a case body 127, a coil 132,
The coil 132 is fitted into the space between the coil attachment protrusion 128 at the center of the case body 127 and the cylindrical part surrounding it, and is connected to the center hole 130 of the coil attachment protrusion 18 on the side. A horseshoe-shaped iron core 126 is fitted and fixed into a hole 131 provided in the section. Hook-shaped attachment portions 129 are formed on both sides of the case body 127.
An electromagnet 125 is attached to the chassis by 29, and an iron core 16 faces the permanent magnet 124.

Next, the operation of the cam body 109 will be explained with reference to FIG. Together with the rotating body 103 (see FIG. 10), the small diameter gear 104 is driven to rotate in the direction of arrow H, and the gear 115 is driven to rotate in the direction of arrow I. Here, since one arm end 121 of the control lever 120 normally enters and engages with the locking recess 112 of the cam body 109, rotation of the cam body 109 is prevented, and the other arm end 121 of the control lever 120 Since the arm end 122 is separated from the engagement gear 118 of the annular gear 116 and the annular gear 116 is free, the gear 1
15 rotates the annular gear 116 in the direction of arrow J via the inward gear 119. That is,
Normally, the annular gear 116 only rotates continuously, the cam body 109 does not rotate, and the position of the head carriage does not change.

To change the position of the head carriage, the coil 132 of the electromagnet 15 is energized so that the iron core 116 repels the permanent magnet 124. As a result, the control lever 120 rotates clockwise in FIG. gear 11
8, the cam body 109 becomes rotatable, while the annular gear 116 is prevented from rotating. Therefore, as the gear 115 is rotationally driven in the direction of the arrow I, the downward protruding pin 113 of the cam body 109 is moved in the direction of the arrow K, and the cam body 109 is rotationally driven in the direction of the arrow L. Cam body 1
09 rotates, the position of a guide pin 159 (to be described later) fitted in the cam groove 110 changes to the position of the cam body 10.
9 in the radial direction, and the head carriage also moves accordingly.

Here, it is assumed that the coil 132 of the electromagnet 15 is energized momentarily. The control lever 120 is the first
In Figure 4, after rotating clockwise, it immediately tries to return to its original position. However, the arm of the lever 120 on the side where the hooked end 121 is formed bends downward in FIG. When the lever 120 rotates in this manner, the hooked arm end 121 is caught in the engagement groove 134 provided on the outer periphery of the cam body 109, and the lever 120 is prevented from returning. When the lever 120 is prevented from returning, the annular gear 116 continues to be locked by the other arm end 122 of the lever 120, and the cam body 109 attempts to rotate in the direction of arrow L. As the cam body 109 rotates, the arm end 121 of the lever 120 is pushed down onto the inclined surface 134a of the engagement groove 134 as shown in FIG. 20, and when it reaches the same level as the lower surface 133, the engagement groove 134 and enters the locking recess 112, the rotation of the cam body 109 is again prevented. Thus, when the electromagnet 125 is momentarily excited, the cam body 109 is intermittently rotated by one tooth, and the head carriage is moved by one track.

The components including the control lever 120, permanent magnet 124, electromagnet 125, etc. constitute head movement control means.

In FIGS. 16 to 19, the head carriage supporting the magnetic head is the upper carriage 1.
50 and a lower carriage 151 as main bodies.
A magnetic head 154 is attached to the head attachment portion 152 of the lower carriage 151 via a gimbal plate 153.
is supported so as to be movable within a predetermined range. Partially cylindrical pin receiving parts 155, 156 are formed on one side of the lower carriage 151, and when the carriage is attached to the chassis, the pin receiving parts are attached to the support pins 160, 160 fixed to the chassis. The carriage 151 is supported so as to move linearly in the radial direction of the disk 3 by contacting the carriages 155 and 156 from above. The other side edge of the carriage 151 is also supported by a pin 161. A cut-and-raised portion 157 is formed on the carriage 151, and a spring 1 is hung between the cut-and-raised portion 157 and the chassis.
The resiliency of 62 forces the entire carriage downward and in the radial direction of the disk. Carriage 1
51, a pin (not shown) fixed to the chassis is lightly pressed against the flat part 158 from above,
It is designed to prevent the entire carriage from lifting up. A guide pin 159 is provided at the distal end of the carriage 151, and this pin 159 engages with the cam groove 110 so that the head carriage 1
51 is moved linearly in the radial direction of the disk 3. The carriage 151 has a cut-and-raised part 1 for attaching the upper carriage 150.
63 is formed, and this cut-and-raised portion has a screw 16.
4 is formed. A screw 169 passing through a hole 166 of a leaf spring 165 and a hole 168 of a push-down spring 167 for pushing down the carriage 150 is screwed into this screw hole 164, so that the push-down spring 167 and the leaf spring 165 are connected to the carriage 15.
It is fixed to the cut and raised portion 163 of 1. Further, the bent piece 170 of the leaf spring 165 comes into contact with the end face 171 of the cut-and-raised portion 163, and the bent piece 172 of the push-down spring 167 contacts the bent piece 170.
In addition, the pair of locking pieces 173 formed by bending the push-down spring 167 press the engaging portions 175 of the groove holes 174 of the leaf spring 165, so that the leaf spring 165 is securely attached to the cut-and-raised portion 163. It is being

Two pins 177 are fixed to the base 176 of the upper carriage 150, and the carriage 150 is attached to the leaf spring 165 by inserting these pins 177 into holes 178 of the leaf spring 165 and caulking them. A bending piece 179 is provided at the intermediate portion of the carriage 150, and this bending piece 179 is adapted to engage with the bending part 58 of the upper case 41 mentioned above, so that the upper case 41 cannot be raised. The bent portion 179 is lifted by the bent portion 58, and the carriage 150 is brought to the raised position. A pad attachment portion 180 is formed at the free end of the carriage 150. As shown in FIG. 18, the pad attachment portion 180 has a shallow recess 181 formed on the lower surface side, and a gimbal plate 182 is fixed to this recess 181. A window hole is formed in the pad attachment portion 180, and a center plate portion 183 is formed so as to straddle the center of this window hole. A recess 184 is formed in the center of the center plate 183, and a lower end 185 of the recess 184 is connected to the pad 186 via the gimbal plate 182.
It is designed to hold down the center of the Padded 1
86 is made of the same material as the magnetic head 154, for example. The pad 186 is capable of gimbaling using the lower end of the recess 184 as a fulcrum. For double-sided recording method, pad 1
A magnetic head is attached in place of 86. The tip end 187 of the push-down spring 167 presses down the recess 184 of the pad attachment part 180 from above, urging the carriage 150 toward the carriage 151.

As shown in FIG. 7, when the cassette 1 is not inserted into the holder 40 to a predetermined position, the pin 8, which is one end of the opening/closing members 81, 81,
The mounting portions 9 and 89 are attached to the carriage 15 by the rotation biasing force of the opening and closing members 81 and 81 caused by the springs 90 and 90.
0, and as shown in FIG. 9,
When the cassette 1 is inserted into the holder 40 to a predetermined position, the opening/closing members 81, 81 are rotated against the urging force, so that one end thereof is separated from a position where it can come into contact with the carriage 150. I'm starting to do that. Therefore, if the cassette 1 is not inserted into the holder 40, the holder 40
Even if you move the camera to the recording/playback position, the carriage 15
0 is blocked by one end of the opening/closing members 81, 81, and the pad 186 cannot come into contact with the disk 3. With the cassette 1 inserted into the holder 40 to a predetermined position, the holder 40 is moved to the recording/reproducing position. Only then can the pad 186 come into contact with the disk 3. With this configuration, even if the disk cassette is moved to the recording/reproducing position without being inserted into the holder, the magnetic head and pad (or magnetic head) will not come into contact with each other, and furthermore, the magnetic There is no possibility that the heads will stick to each other, and there is no fear of damaging the head support mechanism etc. by trying to forcibly separate the magnetic heads that have stuck to each other.

In FIGS. 14 and 16, the cam body 109
A head position detection lever 135 is attached to the side of the shaft 14.
It is rotatably supported around 3. A pin 19 is fixed to the free end of the detection lever 135, and a switch contact piece 140 is pressed into contact with the pin 139, and the spring force of the switch contact piece 140 causes the lever 135 to move its hook-shaped free end 137. is cam body 1
It is urged to rotate in the direction of contacting the locking recess 112 of No. 09. The free end 137 of the lever 135 is
The guide pin 159 of the head carriage is in the cam groove 1.
10, when the magnetic head 154 is in sliding contact with the first track on the outermost circumference of the disk 3, it engages with the locking recess 112a corresponding to the first track. . This locking recess 112a has a stepped portion 136 as a reference detection portion.
are formed continuously. This stepped portion 136 is
Unlike the locking recess 112 described above, it is formed to be deeper, and is provided at a position corresponding to the position of the connecting groove 111. The locking recess 112a is formed to the same depth as the other locking recesses 112, but the stepped portion 13 as a reference detection portion
6 is formed deeper than the recess 112. When the free end 137 of the detection lever 135 is engaged with the locking recess 112, 112a, the switch contact piece 140 is separated from the switch contact pieces 141, 142 on both sides, and the free end of the lever 135 When the lever 137 has fallen into the detection step 136, the contact piece 140 contacts the contact piece 142, detecting that the cam body 109 is in its original position, and the free end 137 of the lever 135 is moved into the locking recess 112. When it rides on the protrusion 138 in between, the contact piece 140 comes into contact with the contact piece 141.

In FIG. 16, the guide pin 159 is located at the outermost position of the cam groove 110, and the head position detection lever 135
shows a state in which the locking recess 112a is located corresponding to the first track next to the stepped portion 136 serving as the reference detection portion. From this state, the cam body 109 is intermittently driven as described above, and its locking recess 11
Assuming that the protrusion 138 between the two is rotated one tooth at a time, the guide pin 159 will shift one step toward the mesial cam edge of the cam edge of the cam groove 110 each time the cam body 109 rotates. As a result, the sliding contact position of the magnetic head 154 with respect to the tracks of the disk 3 is shifted one step at a time to the tracks on the inner circumferential side. In addition, the cam body 109 has one of its protrusions 138.
The switch contact piece 140,1 is rotated by each tooth.
41 makes contact, a signal is emitted, and by counting this signal, it is possible to detect which track the magnetic head 154 is in sliding contact with. Further, the free end portion 137 of the detection lever 135 is connected to the stepped portion 136 as a reference detection portion.
When engaged with the switch contact pieces 140, 14
2 come into contact, and the signal generated thereby indicates that the cam body 109 is at the reference position, that is,
It can be detected that the guide pin 159 is engaged with the connecting groove 111 that connects the two cam grooves 110. In this way, the magnetic head 1
Since the sliding contact position of the contact piece 54 is always detected, the desired signal can be obtained by counting the signals caused by the contact between the contact piece 140 and the contact piece 141, and by detecting the signal caused by the contact between the contact piece 140 and the contact piece 142. A magnetic head 154 can be brought into sliding contact with the track. A component of the cam body 109 including the locking recess 112 and the step 136 constitutes a cam position detection means, and includes a detection lever 135, switch contact pieces 140, 141,
Components including 142 and the like constitute a detection means for detecting the number of the above-mentioned locking recesses as stepped portions and controlling the head feed amount.

In the illustrated example, the magnetic disk cassette 1
is a single-sided type cassette, and recesses 24 and 25 are provided at the top and bottom of the cassette 1 to prevent incorrect insertion, and the cassette can be used by turning it upside down with respect to the magnetic head 154 provided at the bottom. In addition, it is possible to prevent incorrect insertion even when the device is turned upside down.
However, if the recess 25 on one side of the cassette 1 is eliminated so that the cassette 1 can only be inserted with the cassette 1 facing one side, and the pad 186 is replaced with a magnetic head, the cassette 1 and disk device can be converted into a double-sided type. It can be used as
Further, the number of steps in the cam grooves 110 of the cam body 109 can be increased or decreased as appropriate, and one rotation of the cam body moves the magnetic head from the track position on the outermost circumference of the disk to the track position on the innermost circumference. You can also do it like this. Furthermore, since the gist of the present invention is a mechanism for moving the head in the radial direction of the disk using the rotational motion of a continuous rotating body, the type of cassette and the configuration of the cassette loading mechanism are limited to those shown in the drawings. It is not a set of rules and can be changed arbitrarily. Furthermore, the design of the moving mechanism of the magnetic head may be freely changed without departing from the technical matters stated in the claims for utility model registration.

According to the present invention, a cam surface whose diameter changes in a step-like manner is provided on the rotating body, and a head carriage is engaged with this cam surface, so that the rotational position of the rotating body is determined by the step portion and the step portion provided on the rotary body. Since the positioning of the head is controlled by a number of detecting means, it is possible to position the head using a continuously rotating motor, and there is no need to use a sophisticated stepping motor. do not have. In addition, a stepped portion is provided on the rotating body provided with a cam surface, and the reference position and track position of the cam surface are detected by this stepped portion, so that a complex track sensor or a device for detecting the excitation state of a stepper can be used. The reference position for head feeding can be determined with a simple mechanism. Furthermore, by forming irregularities in a circumferential shape on the rotating body, this can be used as a detecting part to control the head feed amount, and the detecting part can also be used as a positioning means for the rotating body by cooperating with an engaging member. As a result, there is no need to separately provide a detection section for head feed amount control and a positioning means for the rotating body, and the configuration is extremely simple. Since this is not a problem, it is possible to ensure accurate head position. In addition, since the uneven shape of a part of the above-described continuous unevenness of the detection section is made different and used as a reference detection section, there is only one detection means consisting of a switch etc. for detecting the above-mentioned detection section and the reference detection section. This is advantageous in terms of space for arranging this detection means.

[Brief explanation of drawings]

Figure 1 is a plan view showing an example of a magnetic disk cassette that can be used in the present invention, Figure 2 is an exploded perspective view of the same cassette, Figure 3 is a partially sectional side view of the same cassette, and Figure 4 is the present invention. Fig. 5 is a plan view showing the upper cover in the above embodiment, Fig. 6 is an exploded perspective view showing the cassette holder part in the above embodiment, and Fig. 7 is a side view showing the above embodiment. 8 is a side view showing different operating modes of the above embodiment according to FIG. 4, FIG. 9 is a plan view showing different operating modes of the above embodiment according to FIG. 7, and FIG. 11 is a plan view of the cam body, FIG. 12 is a developed view of the cam edge of the cam body, and FIG. Fig. 13 is a plan view showing the annular gear in the above embodiment, Fig. 14 is a sectional view taken along the line B-B in Fig. 10, and Fig. 15 is a plan view showing the annular gear used in the rotation conversion means portion in the above embodiment. 16 is a plan view of the magnetic head moving mechanism in the above embodiment, FIG. 17 is an exploded perspective view of the magnetic head support mechanism in the above embodiment, and FIG. 18 is an exploded perspective view of the control mechanism in the above embodiment. 17
19 is a plan view of the magnetic head support mechanism portion, FIG. 20 is an enlarged side view of a part of the cam body, and FIG. 21 is a sectional view of the same cam. It is a longitudinal cross-sectional view of the body. 105... Spindle hub, 109... Cam body as a rotating body, 110... Cam groove having a cam surface, 112... Locking recess as a detection part, 136
... Reference detection section, 140, 141, 142 ... Switch contact piece constituting the detection means, 150 ... Upper carriage constituting the head carriage, 151
. . . Lower carriage constituting the head carriage, 154 . . . Head.

Claims (1)

[Claims for Utility Model Registration] A rotating body supported coaxially with a spindle hub, a cam surface provided on the rotating body whose diameter changes stepwise, and a disk that moves in the radial direction by the cam surface. a head carriage; a detection section having continuous unevenness formed around the rotating body in correspondence with the number of stages of the cam surface; a reference detection section formed in a shape different from the unevenness of the detection section at a position corresponding to the reference position; and a detection means for detecting the reference detection section and counting the number of detection sections to control the head feed amount. and an engaging member that engages with the uneven detection portion to rotationally position the rotating body.