Magnetic head mechanism for reversing head orientation and moving head in tape width direction

A magnetic head mechanism in a magnetic tape apparatus is capable of multiple track, two-way recording and reproduction on magnetic tape. A magnetic head is supported in such a way that it is reversible around an axis that is perpendicular to the surface of the head over which magnetic tape slides, the magnetic tape is moved across the width of the magnetic tape.

BACKGROUND OF THE INVENTION 
The present invention relates to a magnetic head mechanism in a magnetic 
tape apparatus that is capable of multiple track, two-way recording and 
playback. 
Multiple track, two-way recording and playback is typically performed with 
a magnetic tape apparatus such as a backup tape recorder on a magnetic 
disk apparatus. With a view to performing multiple track recording with 
conventional magnetic tape apparatus, U.S. Pat. No. 4,389,689 proposes the 
use of multichannel magnetic heads fixedly connected with a mounting 
plate, and U.S. Pat. No. 4,491,890 proposes that the number of channels on 
a magnetic head be reduced by adapting it to be movable in the direction 
of tape width. 
The first proposal has the disadvantage that a multichannel magnetic head 
is not only difficult to fabricate by machining but also expensive. The 
second approach which depends on moving a magnetic head in the direction 
of tape width suffers the problem that a magnetic head having at least two 
channels is required when recording by a serpentine recording technique or 
a read-after-write technique or performing recording over a large width 
and playback from a narrow width or vice versa (see U.S. Pat. No. 
4,414,593), and this also results in difficulty of machining and high 
production cost. 
In some audiotape recorders, the magnetic head is adapted to be reversible 
in orientation so as to achieve two-way recording and playback. However, 
none of the prior art audio tape recorders have a dual capability for 
reversing the magnetic head and moving it in the direction of tape width 
and the number of tracks on which information can be recorded and 
reproduced has been limited. 
SUMMARY OF THE INVENTION 
The present invention has been accomplished in order to solve these 
problems of the prior art. An object, therefore, of the present invention 
is to provide a magnetic head mechanism that is capable of not only 
performing multiple track, two-way recording and playback with a magnetic 
head as simple as a single-channel head but also realizing both track 
interchange and reversal of magnetic head in an efficient manner with a 
simple arrangement. 
Another major requirement of the industry is to perform high-density 
recording on tape with the guard band between tracks being eliminated, and 
azimuth recording is one possible solution to this problem. To perform 
azimuth recording a multichannel magnetic head having different azimuth 
angles is necessary but such a head is difficult to fabricate. To effect 
azimuth recording, a head with at least two channels having different 
azimuth angles is necessary. As a further problem, in order to perform 
recording on multiple tracks, the magnetic head must be moved over the 
full width of tape and this necessitates a large space, leading to a bulky 
mechanism. 
Therefore, another object of the present invention is to provide a magnetic 
head mechanism that enables azimuth recording with a magnetic head of 
simple configuration while avoiding the increase in the thickness of the 
mechanism. 
The above-stated objects of the present invention can generally be attained 
by a magnetic head mechanism which comprises means for supporting a 
magnetic head reversibly around an axis that is perpendicular to the 
surface of the head over which magnetic tape slides, means for moving the 
support means across the width of the magnetic tape, means for reversing 
the magnetic head by engaging the rear portion of the magnetic head, and 
means for moving the reversing means or the magnetic head in a direction 
having a component perpendicular to the surface of magnetic tape. This 
magnetic head mechanism reverses the magnetic head by allowing the 
reversing means to move relative to the magnetic head in a direction 
having a component perpendicular to the surface of magnetic tape. 
In the mechanism of the present invention, track interchange is effected 
with the moving means which allows both the support means and magnetic 
head to be moved across the width of magnetic tape. When the reversing 
means moves relative to the magnetic head in a direction having a 
component perpendicular to the surface of magnetic tape, the reversing 
means comes into engagement with the rear portion of the magnetic head, 
thereby allowing the magnetic head to be reversed on the support means.

DETAILED DESCRIPTION OF THE INVENTION 
Several embodiments of the magnetic head apparatus of the present invention 
are described hereinafter with reference to the accompanying drawings. 
In FIGS. 1 and 3, a chassis 1 typically made of aluminum by die casting is 
furnished with a subchassis 2 typically made of a resin which 
substantially covers the front half (the lower half of FIG. 1) of the 
chassis 1. As also shown in FIG. 6, the subchassis 2 is furnished with a 
pair of guides 3 that guide the loading of a tape cassette 32 and which 
provide a reference plane for the positioning of the loaded cassette 32 in 
a vertical direction. The guides 3 are formed integrally with the 
subchassis 2 and project in the direction of cassette loading. The guides 
3 are provided symmetrically in the right and left portions of the 
subchassis 2. A leaf spring 6 is attached to the underside of the 
subchassis 2. A roller 4 is disposed between the leaf spring 6 and the 
subchassis 2 and under each guide 3. A ball 5 in a ball holder 27 is also 
provided between the leaf spring 6 and the subchassis 2 and in a median 
portion between the two guides 3. The rollers 4 and the ball 5 are urged 
with the leaf spring 6 toward the top surface of the subchassis 2. The 
rollers 4 cooperate with the ball 5 to hold the loaded cassette in 
position. 
A capstan motor 7 is disposed in the central portion of the chassis 1. The 
motor 7 has a rotor 7a that performs direct drive of a capstan 9 and is 
swingably supported on a pair of fulcrums 8. The motor 7 is positioned 
under the subchassis 2 and the leaf spring 6 and urged in one direction 
around the fulcrums 8 by means of a projection 6a on the leaf spring 6 in 
such a way that the capstan 9 is urged in the direction indicated by the 
arrow in FIG. 1 to be pressed against capstan rollers in the cassette 32. 
A magnetic head support member 12 is mounted on the chassis 1 in such a way 
that it is capable of pivoting around a shaft 14 on the chassis 1 in a 
horizontal plane parallel to the surface of the chassis 1 while it is 
movable in a vertical direction along the shaft 14. The shaft 14 is 
positioned closer to the left end of the head support member 12. A pair of 
supports 12a positioned across the head support member 12 are formed 
integrally with the latter on a location that is closer to its right end. 
A reversing shaft 11a for a head holder 11 penetrates through the supports 
12a. The head holder 11 is capable of rotating about the shaft 11a. A 
magnetic head 10 is fixedly attached to the front end of the head holder 
11. The shaft 11a is provided vertically with respect to the surface of 
the magnetic head 10 over which tape slides, and the support member 12 
supports the magnetic head 10 reversibly around the shaft 11a. The 
magnetic head 10 has an erase core, a recording core and a reproduce core. 
These cores may be arranged in a single set to provide a mono-channel 
configuration. The recording gap is longer than the reproduction gap in 
the direction of tape width or vice versa so that recording can be made 
over a large width and reproduction can be made over a small width, or 
vice versa. 
A positioning projection 11d is provided on one lateral side of the head 
holder 11. The rear end of the reversing shaft 11a projects rearwardly 
from the rear part of support 12a and a leaf-shaped reversing plate 11b is 
secured to that rear end. A spring hook 11c is fixedly provided at the 
front end of the reversing plate 11b, and a reversing spring 20 is 
provided between this spring hook 11c and a reversing spring 20 is 
provided between this spring hook 11c and another spring hook 12c that is 
fixedly provided on the head support member 12. The spring hook 12c is 
disposed at a height generally equal to that of the reversing shaft 11a. 
As best illustrated in FIG. 4, the reversing spring 20 is at its dead 
point when the spring hook 11c is on a line that connects the spring hook 
12c with the reversing shaft 11a. When both the spring hook 12c and the 
reversing shaft 11a come to a position lower than the spring hook 11c, the 
reversing spring 20 goes beyond its dead point and the reversing plate 11b 
rotates in a counterclockwise direction as shown in FIG. 3. If the spring 
hook 12c and the reversing shaft 11a come to a position higher than the 
spring hook 11c, the reversing spring 20 also goes beyond its dead point 
and the reversing plate 11b rotates in a clockwise direction as shown in 
FIG. 5. As the reversing plate 11b rotates in either direction, the 
magnetic head 10 is reversed correspondingly. A pair of positioning screws 
25 and 26 for restricting the range over which the magnetic head 10 should 
be reversed are threaded into the head support member 12 at right and left 
positions across the head holder 11. The positioning projection 11d 
contacts the lower end of either positioning screw 25 and 26 depending 
upon the direction in which the head holder 11 is reversed, thereby 
determining the position of its reversal. 
A sector gear wheel 12b is formed at the right end portion of the head 
support member 12. The gear 12b meshes with a pinion 13a on the output 
shaft of a stepping motor 13 so that the head support member 12 will pivot 
around the shaft 14 as the stepping motor 13 is driven to rotate. The 
stepping motor 13 is provided with a stopper 13b that restricts the range 
over which the pinion 13a should rotate. 
A holder plate 18 is fixed on a chassis 31 in the upper left portion of 
FIG. 1. A track interchanging stepping motor 17 is fixed to the vertical 
lug of the holder plate 18, and a worm 30 is securely attached to the 
output shaft of the stepping motor 17 which generates through the vertical 
lug in a horizontal direction. A screw shaft 19 is fixed downwardly to the 
horizontal lug of the holder plate 18 on the lateral side the shaft 14. 
The female thread of a track interchanging gear 16 is in engagement with 
the screw shaft 19. The track interchanging gear 16 meshes with the worm 
30. The head support member 12 is urged with a spring 15 (FIG. 2) to 
ascend along the shaft 14. The spring 15 is provided between a spring hook 
12d at the left end of the member 12 and another spring hook 18a on the 
holder plate 18 that lies above it. The ascending movement of the head 
support member 12 by the biasing force of the spring 15 is restricted by 
the lower end of the track interchanging gear 16. The screw shaft 19 is 
rendered adjustable in its vertical position by means of a track adjusting 
nut 28 (FIG. 3) in combination with a retainer spring 29 (also see FIG. 3) 
interposed between the screw shaft 19 and the nut 28. The track 
interchanging gear 16 provides means for moving the head support member 12 
across the width of magnetic tape. 
A head rotating cam 21 is fixed on the chassis 31 at the back of the head 
holder 11. As best illustrated in FIG. 7, the cam 21 has an upper cam face 
21a and a lower cam face 21b, as well as a control groove 21c formed 
horizontally between these cam faces. The cam faces 21a and 21b are 
capable of contacting the spring hook 11c integral with the head holder 11 
depending upon the vertical position of the hook 11c. These cam faces have 
an inclined surface that guides the spring hook 11c into the central 
groove 21c when it is pressed against the cam 21. The cam 21 provides 
means for reversing the magnetic head 10 by engaging the spring hook 11c 
at the back of the head. 
As shown in FIG. 1, a flexible printed circuit board 24 for transmitting 
signal between the magnetic head 10 and an external circuit is wound 
around the reversing shaft 11a. Symbol 33 denotes a front bezel. 
The operation of the mechanism described above will proceed as follows. 
Suppose information is recorded or reproduced with the tape running in a 
forward direction in the operational mode shown in FIGS. 1 and 3. In this 
mode, both the track interchanging gear 16 and the head support member 12 
are on their respective lower positions. The reversing spring 20 produces 
a force that causes both the reversing plate 11b and the magnetic head 10 
to rotate around the reversing shaft 11a counterclockwise as shown in FIG. 
3, whereupon the positioning projection 11d contacts the positioning screw 
26 to determine the position of the magnetic head 10 in the direction of 
its rotation. The head support member 12 pivots around the shaft 14 in a 
clockwise direction (as viewed in FIG. 1), whereupon the magnetic head 10 
advances toward the operator together with the head support member 12 in 
such a way that its front face makes slidable contact with magnetic tape 
running either rightward or leftward to perform information recording or 
reproduction. 
When a reverse signal is supplied from an appropriate control means, the 
track interchanging stepping motor 17 is driven to rotate and the head 
support member 12 is returned to a substantially central position in its 
vertical direction which corresponds to the direction of the width of 
magnetic tape. Stated more specifically, when the worm 30 is driven to 
rotate by means of the stepping motor 17, the track interchanging gear 16 
is driven to rotate and ascends along the screw shaft 19, whereupon the 
head support member 12 ascends by the biasing force of the spring 15. When 
the head support member 12 comes to a substantially central portion in its 
vertical direction, the stepping motor 17 is brought to a stop. 
Subsequently, the head reversing stepping motor 13 is driven and the head 
support member 12 is allowed to pivot counterclockwise as shown in FIG. 2 
by the mechanism consisting of the pinion 13a on the motor 13 and the 
sector gear wheel 12b. As the head support member 12 pivots, the head 
holder 11 moves backward and the spring hook 11c on the holder 11 contacts 
the upper cam face 21a of the head rotating cam 21. The spring hook 11c is 
depressed downward and obliquely by the cam face 21a, whereupon the 
reversing plate 11b as well as the head holder 11 and magnetic head 10 
which are integral with the plate are displaced out of the state shown in 
FIG. 3 and rotate in a clockwise direction. In the meantime, the spring 
hook 11c is guided into the central 21c in the cam 21 and the head 
reversing motor 13 thereafter comes to a stop. In this instance, the 
magnetic head 10 is at a substantially median position of the range over 
which it can be reversed, and the reversing spring 20 comes to its dead 
point with the spring hook 12c, reversing shaft 11a and spring hook 11c 
all being aligned on a straight line. 
In the next place, the stepping motor 17 is driven in such a way that the 
head support member 12 is moved upward. The spring hook 11c is restricted 
by the central groove 21c in the cam 21 with respect to its position in a 
vertical direction. When the head support member 12 moves upward, the 
spring hook 11c becomes lower in position than the line connecting the 
spring hook 12c and the shaft 11b, and the elastic force of the reversing 
spring 20 acts to rotate the reversing plate 11b in a clockwise direction 
(as viewed in FIG. 4). If, in this state, the head reversing motor 13 is 
driven so as to pivot the head support member 12 clockwise to the position 
indicated in FIG. 1, thereby advancing the head holder 11, the spring hook 
11c comes out of engagement with the central groove 21c in the cam 21, and 
both the head holder 11 and the magnetic head 10 are rotated clockwise as 
shown in FIG. 5 by the elastic force of the reversing spring 20. Since the 
spring hook 11c comes out of engagement with the central groove 21c as it 
makes slidable contact with the lower cam face 21b of the cam 21, the head 
holder 11 and the magnetic head 10 will be reversed slowly enough to avoid 
any shock that might cause undesired effects such as azimuth error. The 
reversal of the magnetic head 10 is restricted by the positioning 
projection 11d on the head holder 11 which contacts the lower end of the 
positioning screw 25. When the head holder 11 advances toward the 
operator, the front face of the magnetic head 10 comes into slidable 
contact with the reverse running magnetic tape to perform information 
recording or reproduction. 
By driving the stepping motor 17 to rotate during a record/reproduce mode 
in a forward or reverse direction, the head support member 12 and the 
magnetic head 10 supported by it can be controlled with respect to their 
vertical position so as to insure correct track interchanging. 
In the embodiment of the present invention described on the foregoing 
pages, track interchanging is effected by moving the head support member 
12 in the direction of tape width by means of the track interchange gear 
16. At the same time, the magnetic head is reversed by moving it relative 
to the cam 21 in a direction having a component perpendicular to the 
surface of magnetic tape. Because of these features, a simple mechanism 
can be employed for performing not only reversal of the magnetic head 10 
but also track interchanging. As an additional advantage, the magnetic 
head 10 is capable of performing multiple track, two-way recording and 
playback even if its composition is as simple as a monochannel 
configuration. 
Another embodiment of the present invention is described hereinafter with 
reference to the case where azimuth recording is performed. 
FIGS. 9 and 10 show a two-channel head block 10 that comprises the first 
head lA and the second head 2A. Tape (not shown) is supposed to run from 
right to left or vice versa (as viewed in FIGS. 9 and 10) and the first 
and second heads 1A and 2A are disposed in the direction of tape width. 
The first head 1A has a recording (write) head W1 and a reproduce (read) 
head R1 that have a predetermined azimuth angle with respect to the 
recording tracks on tape and which are aligned in the direction of tape 
travel. The second head 2A has a recording (write) head W2 and a reproduce 
(read) head R2 that are also aligned in the direction of tape travel but 
which have a different azimuth angle than the first head 1A. The head 
block 10 enables information to be read after being written. In the first 
head 1A, write head W1 and read head R1 are oriented opposite to W2 and R2 
in the second head 2A with respect to the direction of tape travel. The 
head block 10 is supported in such a way that it is movable in the 
direction of tape width. The head block 10 is also rotatable about a shaft 
that is perpendicular to the surface over which the magnetic tape slides 
and which is disposed at a position substantially median between the first 
and second heads 1A and 2A. The center of rotation provided by such a 
shaft is denoted by C in FIGS. 9 and 10. 
FIG. 11 shows a track format for azimuth recording with the head block 10. 
Assume the magnetic tape runs in the forward direction indicated by arrow 
(A) and in the reverse direction indicated by arrow (B). Recording tracks 
are aligned on tape TP in the order of (11), (9), (13), (7), . . . (1), 
(21), (12), (10), (14), (8), . . . (20), (2) and (22) from top to bottom 
in the direction of tape width. Information is recorded and reproduced 
from track (1) with the first head 1A when tape is running in the forward 
direction. In a similar way, the first head 1A records and reproduces 
information from tracks (3), (5), (7) and (9) when the tape is running in 
the forward direction. Needless to say, information is recorded and 
reproduced from individual tracks as the head block 10 is moved in the 
direction of tape width. On the other hand, information is recorded and 
reproduced from track (2) with the second head 2A when the tape is running 
in the reverse direction. In a similar way, the second head 2A records and 
reproduces information from tracks (4), (6), (8) and (10) when the tape is 
running in the reverse direction. Again, information is recorded and 
reproduced from individual tracks as the head block 10 is moved across the 
tape. 
In the next step, the head block 10 is reversed around the center of 
rotation C, and information is recorded and reproduced from tracks (11), 
(13) (15), (17), (19) and (21) with the second head 2A when the tape is 
running in the forward direction while the first head 1A records and 
reproduces information from tracks (12), (14), (16), (18), (20) and (22) 
when the tape is running in the reverse direction. 
The above is the procedures for performing multiple track recording and 
playback in which information is recorded and reproduced from the upper 
half of the tracks on tape TP when the tape is running in the forward 
direction while the lower half of the tape is used for information 
recording and reproduction when the tape is running in the reverse 
direction. Information is recorded and reproduced from adjacent tracks at 
different azimuth angles since the head block 10 is reversed around the 
center of rotation for allowing the first and second heads 1A and 2A 
having different azimuth angles to perform alternate recording and 
reproduction. As a result, high-density recording can be accomplished 
without the problem of crosstalk even if tracks are closely arranged as 
shown in FIG. 11. 
In FIG. 11, symbols F and R denote the ranges over which the head block 10 
can move across the magnetic tape when it is running in the forward and 
reverse directions, respectively. In the embodiment shown, each of the 
first and second heads 1A and 2A is positioned a distance of L, or one 
fourth the total track width 4L, away from the center of rotation C, so 
the range of movement of each head in the direction of tape width can be 
minimized by adopting a system in which the direction of recording is 
altered whenever it covers one half the tape width as shown in FIG. 11. 
This contributes to a reduction in the overall height of the head 
mechanism. 
As described above, the magnetic head mechanism of the present invention 
enables not only multiple track but also azimuth recording with a simple 
two-channel magnetic head. This magnetic head mechanism has the additional 
advantage of being reduced in height since the heads need to be moved over 
a shorter range in the direction of tape width. In addition, azimuth 
recording can be accomplished without experiencing off-tracking even if 
the track width is not varied in recording and playback modes. 
In the embodiment shown in FIG. 9, each of the first and second heads is 
furnished with a recording and a playback head. This arrangement is not 
necessarily required and, as shown in FIG. 10, the head block 10 may be 
provided with a single first head H1 and a single second head H2 which are 
electrically interchangeable as a recording or a playback head. In this 
case, a full-width erase head E is formed integrally with the head block 
10, and a shaft for reversing the first and second heads H1 and H2 is 
provided at a median position C between these heads. The head block 10 is 
supported in such a way that it is movable across the width of magnetic 
tape. 
In the embodiment shown in FIG. 10, multiple track and azimuth recording 
can also be accomplished by electrically switching the individual heads H1 
and H2 so that either one of them acts as a recording or playback head 
depending upon the direction of tape travel and on the mode of operation 
(whether it is in a recording or playback mode). 
The cam 21 as reversing means and the magnetic head 10 only need to be 
capable of relative movement in a direction having a component 
perpendicular to the surface of magnetic tape. An illustrative embodiment 
that satisfies this requirement is shown in FIG. 8, in which the cam 21 is 
mounted on a lever 37, which pivots to bring the cam 21 into engagement 
with the spring hook 11c in the rear of the magnetic head 10 so as to 
reverse it. The lever 37 is capable of pivoting around a shaft 38 when a 
sector gear wheel 37a at the front end of the lever meshes with the pinion 
13a on the output shaft of the stepping motor 13. The head support member 
12 is capable of moving only in a vertical direction along a guide shaft 
36. Other components including the structure for supporting the magnetic 
head 10 and the mechanism for restricting the vertical position of the 
support member 12 are the same as those used in the embodiment shown with 
reference to FIGS. 1 to 7 and need not be described in detail. 
According to one aspect of the present invention, track interchanging is 
accomplished by moving the head support member across the width of 
magnetic tape with specified moving means while at the same time, the 
magnetic head is reversed by moving it relative to specified reversing 
means in a direction having a component perpendicular to the surface of 
magnetic tape. Because of these features, a simple mechanism can be 
employed for performing not only reversal of the magnetic head but also 
track interchanging in an efficient manner. As an additional advantage, 
the magnetic head is capable of performing multiple track, two-way 
recording and playback even if its composition is as simple as a 
monochannel configuration. 
In accordance with another aspect of the present invention, a head block 
comprising two heads having different azimuth angles is disposed in such a 
way that it is capable of moving across the tape width and being reversed 
about a median position between the two heads. This arrangement enables 
azimuth recording to be performed with a simple two-channel head. At the 
same time, it contributes to a reduction in the thickness or height of the 
magnetic head mechanism by virtue of the decrease in the range of head 
movement across the tape width.