Auto-reverse magnetic-head unit having a flexible conductor board

A magnetic-tape apparatus having a magnetic-head unit includes a head support which is rotatably mounted by a mounting device and has a duct through which a flexible conductor board is passed, which conductor board for connection to a signal processing circuit comprises a widened connecting portion. The head support has at least one slot which extends at least over the entire length of the duct, passes through the head support and terminates in the duct, through which slot the flexible conductor board can be passed while its original flat shape is maintained.

BACKGROUND OF THE INVENTION 
The invention relates to a magnetic-tape apparatus comprising a 
magnetic-head unit for scanning a magnetic tape, which unit is pivotable 
through 180.degree. between two scanning positions about a pivotal axis 
substantially perpendicular to the magnetic tape being scanned and which 
is carried by a head support which is rotatably mounted by means of a 
mounting device and which is rotatable about the pivotal axis, which head 
support has a duct leading to the magnetic-head unit carried by the head 
support and to the end of the head support which is remote from the 
magnetic-head unit, which duct is traversed by at least a flexible 
conductor board having conductor tracks connected to the magnetic-head 
unit and also leading to a signal processing circuit of the apparatus, 
which board at its end leading to the signal processing circuit comprises 
a connecting portion which is widened relative to the section situated in 
the duct. 
A magnetic-tape apparatus of the type defined in the opening paragraph is 
known and is commercially available. In the known apparatus, the flexible 
conductor board comprises only six adjacent conductor tracks for 
electrically connecting the magnetic-head unit to the signal-processing 
circuit. Owing to the comparatively small number of conductor tracks these 
tracks can be comparatively wide, so that mechanically the conductor 
tracks are comparatively robust. In the area adjacent the magnetic-head 
unit and extending through the duct the flexible conductor board is 
divided into two conductor board strips by a dividing zone which extends 
in the same direction as the duct and whose width is slightly smaller than 
the diameter of the duct, which is of circular cross-section in this case. 
This ensures that the two conductor board strips in the duct always have a 
flat shape, so that the conductor board strips and the conductor tracks 
provided on these strips are not mechanically loaded. To pass the flexible 
conductor board through the duct of the head support, which is necessary 
during manufacture of the apparatus, there are two possibilities. With the 
first possibility the conductor tracks of the conductor board are first 
electrically connected to the magnetic-head unit, which means that 
subsequently the widened connecting portion of the flexible conductor 
board has to be passed through the duct. For this purpose the widened 
connecting portion should be rolled up about a rolling axis extending in 
the longitudinal direction of the duct and should be pushed through the 
duct in its rolled-up condition. Both as a result of rolling-up and 
pushing through of the connecting portion it is not unlikely, despite the 
comparatively small number of conductor tracks and the resulting 
comparatively high mechanical strength of the conductor tracks of the 
flexible conductor board, that the mechanical loading gives rise to 
damaging of the conductor tracks at the location of the connecting 
portion, which may lead to interruptions in the conductor tracks. In such 
cases the entire magnetic-head unit is unserviceable and has to be 
removed, which is inconvenient and undesirable. With the second 
possibility the two narrow conductor board strips are passed through the 
duct and subsequently the conductor tracks of the conductor board are 
electrically connected to the magnetic-head unit. However, this is 
undesirable and problematic in view of a reliable, simple and automated 
electrical connection of the conductor tracks of the flexible conductor 
board to the magnetic-head unit or to the corresponding connections of the 
magnetic-head unit. 
SUMMARY OF THE INVENTION 
It is an object of the invention to preclude the above problems and to 
construct a magnetic-tape apparatus of the type defined in the opening 
paragraph in an advantageous manner such that before they are passed 
through the head support the conductor tracks of the flexible conductor 
board are electrically connected to the magnetic-head unit and that 
subsequently the flexible conductor board can be passed through the head 
support without the risk of damaging of the conductor tracks of the 
conductor board, even if the conductor board comprises a large number of 
conductor tracks. 
To this end the invention is characterised in that the head support has at 
least one slot which extends at least over the entire length of the duct, 
extends through the head support and terminates in the duct, said slot 
being constructed in such a manner that the flexible conductor board can 
be passed through the slot while its flat shape is maintained. In a very 
simple manner it is thus achieved that the entire flexible conductor board 
and, consequently, also the widened connecting portion of the flexible 
conductor board can be passed through the head support while its original 
flat shape is maintained, so that the conductor tracks are not 
mechanically loaded when the flexible conductor board is passed through 
and interruption of the conductor tracks is substantially excluded. 
The head support may have two slots which are opposed diametrically 
relative to the pivotal axis and which each extend over the entire 
dimension of the head support in the direction of the pivotal axis, and 
consequently comprises two parts which are joined after introduction of 
the flexible conductor board into the duct and which are held together by 
separate connection means. Such a construction has the advantage that the 
flexible conductor board can be passed very simply through the head 
support but in order to achieve a sufficiently high mechanical stability 
of the two-part head support additional separate means are needed which 
make the head support and hence the magnetic-tape apparatus more 
complicated and expensive. In a magnetic-tape apparatus in accordance with 
the invention, in which the head support comprises a tubular supporting 
member which is coaxial with the pivotal axis and which at its end which 
faces the magnetic-head unit changes into a holding member having a larger 
radial dimension than the tubular supporting member, it is found to be 
advantageous if the slot comprises a first slot portion, which traverses 
the wall of the tubular supporting member over its entire length and 
extends in the direction of the pivotal axis, and a second slot portion, 
which partly passes through the holding member, is inclined relative to 
the first slot portion and terminates in the first slot portion. In this 
way it is achieved that the head support can consist of a single part, 
which has the advantage of a high mechanical stability of the head support 
and enables it to be manufactured cheaply using plastics technology, which 
has the advantage of lower production costs, and that in addition to these 
advantages the flexible conductor board can be passed simply through the 
head support. 
With such a magnetic-tape apparatus it is found to be very advantageous if 
there is provided an end member mounted on the tubular supporting member 
of the head support, which end member has a passage for the flexible 
conductor board, which passage extends in the direction of the pivotal 
axis, and a slot which extends radially of the pivotal axis from the outer 
surface of the end member up to its passage, through which slot the 
flexible conductor board can be introduced into the passage, by means of 
which end member the first slot portion of the slot in the tubular 
supporting member can be closed at least partly. In this way the flexible 
conductor board is very effectively prevented from sliding out of the duct 
of the head support by simple means. 
With such a magnetic-tape apparatus it is found to be very advantageous if 
the end member comprises a rib which extends radially of the pivotal axis 
and from the duct of the head support into the first slot portion of the 
slot, which slot portion extends through the wall of the tubular 
supporting member, which rib has a rounded free end by which the 
circumferential surface of the tubular supporting member is completed to a 
circularly cylindrical surface at the location of the first slot portion. 
In this way it is achieved that, despite the presence of the slot in the 
tubular supporting member, the circumferential surface of this tubular 
supporting member, at least at the location of the rib, is a substantially 
continuous circularly cylindrical surface, which cooperates with a bore to 
guarantee a correctly supported head support. 
It is also found to be advantageous if the end member comprises two 
mutually parallel guide surfaces for the flexible conductor board, between 
which guide surfaces the conductor board is passed with clearance. This 
ensures that the entire part of the flexible conductor plate which 
traverses the head support is not twisted when the magnetic-head unit is 
pivoted.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 shows a part of a magnetic-tape apparatus 1 constructed to receive a 
cassette 2, which is shown diagrammatically in dash-dot lines in FIG. 1. 
For this purpose the apparatus 1 has, for example, a trough-shaped 
cassette holder, not shown. The cassette 2 accommodates a magnetic tape 3. 
The magnetic tape 3 extends from a first reel hub 4, on which the magnetic 
tape 3 has been wound to form a tape spool 5 in the situation shown, to a 
second reel hub 9 via a tape guide 6, along a long narrow side 7 of the 
cassette and via a further tape guide 8, and can thus be wound between the 
two reel hubs 4 and 9. 
The magnetic-tape apparatus 1 comprises a substantially plate-shaped 
chassis 10. A first rotatably drivable winding mandrel 11 and a second 
rotatably drivable winding mandrel 12 are rotatably supported on the 
chassis 10 to rotate the first reel hub 4 and the second reel hub 9 
respectively. A first capstan 13 and a second capstan 14 are also 
rotatably supported on the chassis 10. Each of the two capstans 13 and 14 
is rotationally locked to one of two flywheels 15 and 16. A belt 17, which 
is guided on a pulley 18, is wrapped oppositely around part of the 
circumferential surfaces of the two flywheels 15 and 16. The pulley 18 can 
be driven with a constant speed by a motor 19 secured to the chassis 10 in 
an anticlockwise direction as viewed in FIG. 1. The second winding mandrel 
12 can be driven by the first capstan 13 and the first winding mandrel can 
be driven by the second capstan 14 in known manner by means of a 
selectively activated intermediate drive mechanism, which comprises for 
example a plurality of drive wheels and a friction coupling to compensate 
for differences in speed. 
The apparatus 1 further comprises a mounting plate 23 which is guided on 
the chassis 10 by means of three pin-slot joints 20, 21 and 22 so as to be 
movable perpendicularly to the long narrow side 7 of the cassette. Such a 
mounting plate is often also referred to as a head support. The mounting 
plate 23 carries a first pressure roller 24 and a second pressure roller 
25, which are pivotably supported on the mounting plate 23 by means of 
levers, not shown, and which can be applied selectively in resilient 
engagement with one of the two capstans 13 and 14, the magnetic tape 3 
being situated between the relevant capstan and the relevant pressure 
roller. In this way the magnetic tape 3 can be driven with a constant tape 
speed by means of a rotatably driven capstan against which the magnetic 
tape is pressed by the associated pressure roller. In a "normal forward" 
mode the first pressure roller 24 is pressed against the first capstan 13, 
as is shown in FIG. 1. The motor 19 then drives the first capstan 13 with 
a constant speed in the anti-clockwise direction viewed in FIG. 1, so that 
the magnetic tape 3 is driven in the tape transport direction indicated by 
an arrow 26. The magnetic tape 3 is then wound onto the second reel hub 9, 
which is driven by the second winding mandrel 12. In a "normal reverse" 
mode, also referred to as "reverse" mode the second pressure roller 25 is 
pressed against the second capstan 14, the motor 19 driving the second 
capstan 14 in the clockwise direction viewed in FIG. 1, so that the 
magnetic tape 3 is driven in the tape transport direction indicated by an 
arrow 27. The magnetic tape 3 is then wound onto the first reel hub 4 
driven by the first capstan 11. 
The mounting plate 23 of the magnetic-tape apparatus 1 further carries a 
magnetic-head unit 28 for recording and reproducing information signals, 
for example audio signals. The magnetic-head unit 28 is mounted in a metal 
housing 29 in a manner not shown, which housing comprises a fork-shaped 
tape guide 30 and 31 situated at opposite sides of the magnetic-head unit 
28. The magnetic-head unit 28 is pivotable through 180.degree. between two 
scanning positions about a pivotal axis 32 which extends perpendicularly 
to the long narrow side 7 of the cassette and perpendicularly to the 
magnetic tape 3 being scanned, one of said scanning positions being shown 
in FIGS. 1 to 4. Each scanning position corresponds to one of the two 
opposite tape-transport directions 26 and 27. In each scanning position 
the magnetic-head unit 28 scans a track area of the magnetic tape 3 by 
means of magnet-core systems 33, 34 and 35, shown diagrammatically in FIG. 
4, which are disposed eccentrically of the pivotal axis 32 of the 
magnetic-head unit 28. The magnet-core systems 33 comprise two magnet 
cores which are juxtaposed in the track-width direction and which are 
constructed for the reproduction of stereophonically recorded audio 
signals in analog form. The magnet-core system 34 comprises nine magnetic 
cores which are juxtaposed in the track-width direction and which are 
constructed for recording audio signals in digital form. The magnet-core 
system 35 also comprises nine magnetic cores which are juxtaposed in the 
track-width direction and which are constructed for the reproduction of 
audio signals in digital form. 
In FIGS. 3 and 4, the two track areas of the magnetic tape 3 bear the 
reference numerals 36 and 37. In the situation shown in FIGS. 2 and 3, the 
magnetic tape 3 is driven in the tape-transport direction 26 and the 
magnetic-head unit 28 consequently occupies the scanning position in which 
it scans the track area 36 by means of its magnet-core system 33 and the 
track area 37 by means of its two magnet-core systems 34 and 35. When the 
magnetic tape 3 is driven in the opposite tape-transport direction 27 the 
magnetic-head unit 28 occupies the reversed other scanning position in 
which it scans the track area 37 by means of its magnet-core system 33 and 
the track area 36 by means of its two magnet-core systems 34 and 35. FIG. 
2 shows two tape guides 38 and 39 at the cassette side in dash-dot lines, 
which tape guides provide the necessary contact of the magnetic tape 3 
with the magnetic-head unit 28. 
The magnetic-head unit 28 is carded by a head support 40 which is pivotable 
about the pivotal axis 32. To hold the magnetic-head unit 28 the head 
support 40 comprises a holding member in the form of a cylindrical 
supporting disc 41 having an outer cylindrical surface 42. Two 
block-shaped projections 44 and 45, which are integral with the supporting 
disc 41, project from a radial surface 43 of the disc 41 in the direction 
of the pivotal axis 32. A plate 46 is secured to these two projections 44 
and 45 by means of two screws 47 and 48. The housing 29 of the 
magnetic-head unit 28 is connected to the plate 46. 
On the mounting plate 23 the magnetic-tape apparatus 1 has a mounting 
device 49 with a mounting recess 50 for rotatably mounting the head 
support 40. The mounting device 49 is partly constituted by the mounting 
plate 23 itself and by a substantially disc-shaped bearing member 51. At 
the location of its radial surface 52 facing the magnetic-head unit 28 the 
bearing member 51 has two ridges 53 and 54 which are mirror-inverted 
relative to one another and which have end portions which are inclined 
towards one another at their ends which are remote from the mounting plate 
23. The portions of the two ridges 53 and 54 which extend perpendicularly 
to the mounting plate 23 each comprise a straight bead 55 and 56, 
respectively, of substantially semicircular cross-section whose 
semicircular bounding walls 57 and 58, which extend perpendicularly to the 
two tape-transport directions 26 and 27, bound the mounting recess 50 in 
which the supporting disc 41 is rotatably mounted. Two further bounding 
walls 59 and 60 of the mounting recess 50 are defined by the inclined end 
portions of the ridges 53 and 54. A further bounding wall 61 of the 
mounting recess 50 is formed by a part of the wall of mounting plate 23 
which faces the magnetic-head unit 28. This bounding wall 61 of the 
mounting recess 50 extends in the same direction as the two tape-transport 
directions 26 and 27. With its supporting disc 41 the head support 40 is 
rotatable with clearance in the mounting recess 50 bounded by said 
bounding walls 57, 58, 59, 60 and 61. In practice this clearance is 
approximately one tenth of a millimeter. As can be seen in FIG. 3, the 
mounting recess 50 of the mounting device 49 has areas 62, 63, 64, 65 and 
66 where the supporting disc 41 of the head support 40 is free, so that in 
a cross-sectional view of the mounting recess 50 the supporting disc 41 of 
the head support 40 is only in point contact with the mounting recess at 
predetermined contact points, as will be explained hereinafter. In order 
to limit axial movement of the head support 40 its supporting disc 41 
cooperates with a rib 67 which projects from the mounting plate 23, via 
which rib the supporting disc 41 is pressed in the direction of the 
pivotal axis 32 when the head support 40 is inserted into the mounting 
device 49. 
At the radial surface 68 of the supporting disc 41 which is remote from the 
magnetic-head unit 28 the head support 40 comprises a first positioning 
cylinder 69 which is coaxial and integral with said disc. A toothed wheel 
70 is coaxial and integral with said first positioning cylinder 69. A 
second positioning cylinder 71 of smaller diameter is coaxial and integral 
with the toothed wheel 70. A bore 72 extends through the supporting disc 
41, the first positioning cylinder 69, the toothed wheel 70 and the second 
positioning cylinder 71, and in the supporting disc 41 it flares towards 
the magnetic-head unit 28. The bore 72 forms a duct leading to the 
magnetic-head unit 28 and to the end 73 of the head support 40 which is 
remote from the magnetic-head unit 28, electrical leads to the 
magnetic-head unit 28 being passed through the bore, as will be described 
in more detail hereinafter. The first positioning cylinder 69, the toothed 
wheel 70 and the second positioning cylinder 71, which are all traversed 
by the bore 72, together constitute a tubular supporting member 74 which, 
in addition to the supporting disc 41, has been provided for rotatably 
mounting the head support 40. 
As mentioned hereinbefore, the magnetic-head unit 28 is pivotable through 
180.degree. between two scanning positions. Consequently, the head support 
40 is also rotatable through 180.degree. between two operating positions. 
These two operating positions are defined by means of two adjustable 
positioning screws 75 and 76, whose free ends depending on the operating 
position of the head support 40 engage with a positioning projection 77 
which projects radially from the first positioning cylinder 77, as is 
shown in FIGS. 2 and 3 for the operating position of the head support 40 
which corresponds to the "normal forward" mode. The positioning screws 75 
and 76 are each fitted in a plate-shaped projection 78 and 79 of the 
bearing member 51. The two projections 78 and 79 of the bearing member 51 
project from the radial surface 80 which is remote from the magnetic-head 
unit 28 towards the pivotal axis 32. 
In order to reverse the magnetic-head unit 28 and the head support 40 the 
apparatus comprises an actuating device 81 for the head support 40, which 
device is shown in FIG. 1. The actuating device 81 comprises a toothed 
wheel 82 which can be driven in opposite directions of rotation by means 
of a motor, in a manner not shown. The toothed wheel 82 meshes with a 
toothed rack 83 which is guided to be movable in its axial direction 
between two stops 84 and 85, shown diagrammatically. A leg spring 87 is 
fitted around a pin 86 projecting from the toothed rack 83 and has two 
legs 88 and 89 between which a pin 90 projecting from the rack 83 extends, 
thereby defining the position of the leg spring 87. The two legs 88 and 89 
of the leg spring 87 tend to move towards one another. A further pin 91 
extends between the two legs 88 and 89 of the leg spring 87 and is 
connected to a toothed rack 92 which is guided on the mounting plate 23 so 
as to be movable in its longitudinal direction. The toothed rack 92 is in 
mesh with the toothed wheel 70 of the head support 40. 
In a known manner, reversal of the magnetic-head unit 28 is possible only 
if the magnetic-head unit 28 has been moved so far out of the scanning 
position shown in FIG. 1 in the direction indicated by the arrow 93 that 
it has been withdrawn from the cassette 2. This movement of the 
magnetic-head unit 28 is obtained by moving the mounting plate 23 in the 
direction indicated by the arrow 93, as is shown in dash-dot lines in FIG. 
1 for a part of the mounting plate 23 and the end of the toothed rack 92 
carrying the pin 91. As is illustrated by the dash-dot lines, the pin 91 
is also situated between the two legs 88 and 89 of the leg spring 87 when 
the mounting plate 23 has been moved, thereby guaranteeing that in this 
position of the mounting plate 23 force is transmitted from the 
motor-driven toothed wheel 82 and the toothed rack 83 to the pin 91 via 
the leg spring 87 and consequently to the toothed rack 92, the toothed 
wheel 70 and the head support 40. Therefore, before the magnetic-head unit 
28 is reversed, the mounting plate 23 is moved in the direction indicated 
by the arrow 93 and after the reversal of the magnetic-head unit 28 the 
mounting plate 23 is moved back in a direction opposite to that indicated 
by the arrow 93. How this movement of the mounting plate 23 is effected is 
not relevant to the present invention and is therefore not indicated. 
For additionally positioning the head support 40 in its two operating 
positions this support is integral with the first coaxial positioning 
cylinder 69 and the second coaxial positioning cylinder 71. For the 
cooperation with the first positioning cylinder 69 there are provided two 
positioning ribs 94 and 95 which have substantially semicircular 
cross-section shapes and extend perpendicularly to the two tape-transport 
directions 26 and 27. The two positioning ribs 94 and 95 are each arranged 
on one of two blocks 96 and 97 which project from the plate-shaped 
projections 78 and 79 of the bearing member 51 towards the mounting plate 
23. The second coaxial positioning cylinder 71 extends through an opening 
98 in a positioning plate 99 which projects perpendicularly from the 
mounting plate 23. At its end which is remote from the mounting plate 23 
the opening 98 in the positioning plate 99 is closed by a member 100 which 
is secured to the positioning plate 99 by two laterally projecting pins 
101 and 102 pressed into corresponding bores in the positioning plate 99. 
The reversal of the magnetic-head unit 28 is described below. It is assumed 
that the magnetic-head unit 28 is in the scanning position not shown in 
FIGS. 1 to 3, in which the magnet-core system scans the track area 37 and 
the two magnet-core systems 34 and 35 scan the track area 36, the toothed 
rack 83 then being in the position indicated by the dash-dot line shown in 
FIG. 1, in which it abuts against the stop 85. The mounting plate 23 is 
first moved in the direction indicated by the arrow 93, so that the 
magnetic-head unit 28 is withdrawn from the cassette 2. Subsequently, the 
toothed wheel 82 is driven clockwise in FIG. 1, causing the toothed rack 
83 to be moved into its position shown in solid lines in FIG. 1, in which 
position it abuts against the stop 84. The pin 91 is then moved by means 
of the leg spring 87 via its leg 89, causing the leg spring 87 to be 
tensioned and the toothed rack 92 to be moved in the direction indicated 
by the arrow 103. As a result of this, the toothed wheel 70 is rotated 
anti-clockwise as viewed in FIG. 3. In this way the head support 40 is 
also rotated anti-clockwise until the positioning projection 77 abuts 
against the free end of the positioning screw 76. When this is the case 
the head support 40 has reached its operating position in which the 
magnetic-head unit 28 occupies the scanning position in which it can scan 
the track area 36 by means of its magnet-core system 33 and the track area 
37 by means of its two magnet-core systems 34 and 35. Subsequently, the 
mounting plate 23 is moved back in a direction opposite to that indicated 
by the arrow 93, the magnetic-head unit 28 again being applied to the 
cassette 2 to scan the magnetic tape 3. This operating position is 
illustrated in FIGS. 1 to 4. 
In the operating position illustrated in FIGS. 1 to 4 the leg 89 of the leg 
spring 87, which acts upon the toothed rack 83, continually exerts a force 
on the toothed rack 92 via the pin 91, as a result of which the toothed 
rack 92 is urged in the direction indicated by the arrow 103. Thus, the 
leg spring 97 forms a loading means which in the present operating 
position of the head support 40 continually urges the toothed rack 92 in 
the direction indicated by the arrow 103. As a result of this load exerted 
by the leg spring 87, the toothed rack 92 continually exerts a force on 
the toothed wheel 70. This force causes the positioning projection 77 to 
be pressed against the free end of the positioning screw 76. Moreover, 
this force presses the first positioning cylinder 69 against the 
positioning rib 94 on the block 96. Said force also presses the second 
positioning cylinder 71 against that bounding wall 104 of the opening 98 
in the positioning plate 99, which wall faces the mounting plate 23. Since 
the positioning projection 77 is pressed against the free end of the 
positioning screw 76 by means of the toothed rack 92 a torque acting on 
the head support 40 is produced and presses the supporting disc 41 of the 
head support 40 with its surface 42 against the bounding wall 61 of the 
mounting recess 50 formed in the mounting plate 23, the supporting disc 41 
of the head support 40 and the bounding wall 61 of the mounting recess 50 
of the mounting device 49 being in engagement with one another at a 
contact area 105 which is point-shaped in a cross-sectional view of the 
mounting recess 50. Since the first positioning cylinder 69 is pressed 
against the positioning rib 94 on the block 96 by means of the toothed 
rack 92 a further torque acting on the head support 40 is produced and 
presses the supporting disc 41 of the head support 40 with its surface 42 
against the bounding wall 58 of the bead 56, the supporting disc 41 of the 
head support 40 and the bounding wall 58 of the bead 56 being in 
engagement with one another at a contact area 106 which is also 
point-shaped in a cross-sectional view of the mounting recess 50. 
The operating position of the head support is thus defined exactly in the 
manner described above. In this operating position the surface 42 of the 
supporting disc 41 of the head support 40 is pressed only against the two 
above-mentioned contact areas 105 and 106. Since the head support 40 is in 
engagement with the cross-sectionally point-shaped bearing areas 105 and 
106 each time that it is rotated into this operating position it is 
guaranteed that the head support 40 always assumes the operating position 
defined by the two contact areas 105 and 106 in an unambiguously 
reproducible manner. Thus, it is achieved that the magnetic-head unit 28 
carried by the head support 40 is always set to the same scanning position 
in an unambiguously reproducible manner, thereby guaranteeing that a 
correct scanning performance of the magnetic-head unit 28 is maintained. 
As can be seen in FIGS. 2 and 4 the magnetic tape 3 moves past the 
magnetic-head unit 28 in the tape-transport direction 26 in the shown 
operating position of the head support 40. The magnetic tape 3 then exerts 
a frictional force on the magnetic-head unit 28. This frictional force 
extends in the tape-transport direction 26 and, via the magnetic-head unit 
28, it produces a torque which acts upon the head support 40 and which 
assists the leg spring 87 in pressing the supporting disc 41 of the head 
support 40 against the contact area 106 in the mounting recess 50. This 
ensures that even if a large frictional force is exerted on the 
magnetic-head unit 28 this unit 28 remains in its scanning position. 
In the operating position of the head support 40 which is reversed relative 
to that described above and which is not shown in FIGS. 1 to 4, the leg 
spring 87 forming the loading means always subjects the toothed rack 92 to 
a force opposite to the direction indicated by the arrow 103. As a result 
of this, the toothed rack 70 always exerts a force on the toothed wheel 70 
of the head support 40, by which the positioning projection 77 is pressed 
against the free end of the other positioning screw 75, the first 
positioning cylinder 69 is pressed against the other positioning rib 95 on 
the block 97, and the second positioning cylinder 71 is pressed against 
the bounding wall 104 of the opening 98 in the positioning plate 99. 
Moreover, the supporting disc 41 of the head support 40 is then pressed 
against the bounding wall bounding wall 61 of the mounting recess 50 and 
against the bounding wall 57 of the other bead 55 in the mounting recess 
50, the supporting disc 41 of the head support 40 again being in 
engagement only with two predetermined cross-sectionally point-shaped 
contact areas on the mounting device 49, i.e. at the contact area 105 and 
at a further contact area 107 on the bounding wall 57 of the bead 55, so 
that also in this operating position of the head support 40 the 
magnetic-head unit 28 always occupies the same scanning position, thereby 
guaranteeing a correct scanning by the magnetic-head unit 28. 
As already stated, the magnetic-head unit 28 has three magnet-core systems 
33, 34 and 35, which serve for scanning two track areas 36 and 37. The 
electrical coils of these magnet-core systems 33, 34 and 35 are connected 
to a signal processing circuit 108, shown diagrammatically in FIG. 1, via 
electrical leads. The electrical leads are constituted by a flexible 
conductor board 109, which is shown diagrammatically in FIGS. 1 to 3 and 
realistically in FIG. 5. As can be seen in FIG. 5 the flexible conductor 
board 109 comprises a connecting portion 110 connected to the 
magnetic-head unit 28. Adjacent this connecting portion 110 a dividing 
zone 111 divides the flexible conductor board in its longitudinal 
direction into two conductor board sections 112 and 113. The width of 
these conductor board sections 112 and 113 is slightly smaller than the 
diameter of the bore 72 through the tubular supporting member 74 of the 
head support 40. At the ends 114 and 115 of its two conductor board 
sections 112 and 113 leading to the signal processing circuit 108 the 
flexible conductor board 109 has connecting portions 116 and 117 which are 
widened in comparison with the conductor board sections 112 and 113 which 
are disposed in the duct 72 in the assembled condition. In the two 
connecting portions 116 and 117 the conductor tracks have a larger width 
than in the two conductor board sections 112 and 113. This larger width of 
the conductor tracks is necessary because the widened connecting portions 
116 and 117 are adapted to cooperate with so-called printed-circuit 
connectors via which the electrical connection between the conductor 
tracks of the flexible conductor board 109 and the signal processing 
circuit 108 is made. In order to guarantee a correct insertion of the 
widened connecting portions 116 and 117 into the printed-circuit 
connectors 118 and 119 shown diagrammatically in FIG. 1, the widened 
connecting portions 116 and 117 are additionally stiffened so that they 
can bend only to a very limited extent. Each of the two connecting 
portions 116 and 117 and each conductor board section 112 and 113 
connected to the respective connecting portion comprises fifteen conductor 
tracks. 
During assembly of the magnetic-tape apparatus 1 the flexible conductor 
board 109, which is connected directly to the magnetic-head unit 28 in the 
housing 29 by means of its connecting portion 110, must be passed through 
the head support 40. For this purpose, the head support 40 has a slot 120 
which extends over the full length of the duct 72 and which passes through 
the head support 40 radially of the pivotal axis 32 and terminates in the 
duct 72, the slot being constructed in such way that the flexible 
conductor board 109 can be passed through the slot 120 while maintaining 
its flat shape. 
As can be seen in FIG. 6, the slot 120 comprises a first slot portion 122, 
which traverses the wall 121 of the tubular supporting member 74 over its 
entire length and extends in the direction of the pivotal axis 32, and a 
second slot portion 123, which partly passes through the supporting disc 
41 forming the holding member for holding the magnetic-head unit 128, 
which second slot portion 123 is inclined relative to the first slot 
portion 122 and terminates in the first slot portion 122. 
As can also be seen in FIG. 6, the duct 72 in the form of a bore has a 
diameter d. Without special steps each of the two widened connecting 
portions 116 and 117 of the flexible conductor board 109 would have to be 
rolled up to allow the passage of the flexible conductor board 109 through 
this duct 72, which is not practical because the connecting portions 116 
and 117 have been stiffened and this would lead to breaking of the 
conductor tracks. By providing the slot 120 of a construction as shown in 
solid lines in FIG. 6, a flexible conductor board whose width is slightly 
smaller than the radial dimension D of the slot 120, which dimension D is 
substantially larger than the diameter d of the duct 72, can be passed 
through this slot 120 in the direction of the pivotal axis 32 without 
having to change the original flat shape of the flexible conductor board. 
In the present embodiment, in which the flexible conductor board 109 has 
two conductor board sections 112 and 113 which each change into a widened 
connecting portion 116 and 117 respectively, the sections 112, 113 and the 
connecting portions 116, 117 are arranged with their main surfaces 
adjacent each other, after which they are passed through the slot 120. 
In FIG. 6 a duct of a second construction is shown in dash-dot lines, the 
duct comprising two tapered parts in its area facing the magnetic-head 
unit. This construction of the duct enables an even wider flexible 
conductor board, whose width corresponds substantially to the value D1, to 
be passed through the slot 120 in the direction indicated by the arrow 
124. 
By providing the slot 120 it is achieved in a very simple manner that the 
entire flexible conductor board 109 and consequently also the widened 
connecting portions 116 and 117 of the flexible conductor board 109 can be 
passed through the head support 40 with their original flat shape, so that 
when the flexible conductor board 109 is passed through the conductor 
tracks on this board 109 are not subjected to any mechanical loads and 
consequently damaging of these conductor tracks or an interruption of 
these conductor tracks is excluded. Moreover, this yields the advantage 
that the flexible conductor board 109 can already be connected to the 
magnetic-head unit 28 with its connecting portion 110 before it is passed 
through the head support 40. This is very advantageous because in the 
present case, in which the connecting potion 110 has thirty conductor 
tracks in total, these tracks are very narrow, which narrow conductor 
tracks can only be connected to the corresponding terminals of the 
magnetic-head unit by a very expensive and intricate method, which 
requires the use of a separate device by means of which the flexible 
conductor board is also connected to the magnetic-head unit in the course 
of the production of the entire magnetic-head unit. 
As is apparent from FIGS. 1, 2, 3 and 6, the magnetic tape apparatus 1 
comprises an end member 125 mounted on the tubular supporting member 74 of 
the head support 40. As is shown in particular in FIG. 7, the end member 
125 has a passage 126 for the flexible conductor board 109, i.e. for the 
two sections 112 and 113 of the flexible conductor board 109, which 
passage extends in the direction of the pivotal axis 32. The end member 
125 further has a slot 128 which extends radially of the axis 32 from the 
outer surface 127 of the end member 125 up to its passage 126. The 
flexible conductor board 109, i.e. its conductor board sections 112 and 
113, can be passed through the slot 128 into the passage 126 of the end 
member 125. During assembly of the apparatus 1 the flexible conductor 
board 109 is first passed through the slot 120 in the head support 40, 
after which the conductor board sections 112 and 113 are situated in the 
bore 72 of the supporting member 74. Subsequently, the end member 125 is 
slid onto the conductor board sections 112 and 113 with its slot 128 until 
the conductor board sections 112 and 113 are situated in the passage 126. 
After this the end member 125 is slid in the direction of the pivotal axis 
32 onto the tubular supporting member 74, i.e. onto the second positioning 
cylinder 71 thereof. For this purpose, the end member 125 comprises a 
substantially cylindrical portion 129, which is inserted into the bore 72 
in the second positioning cylinder 71. The passage 126 of the end member 
125 is situated in this cylindrical portion 129. The cylindrical portion 
129 of the end member 125 is integrally connected to a hollow cylindrical 
portion of the end member 125 via a disc-shaped portion 130 of the end 
member 125. By means of this end member 125 the first slot portion 122 of 
the slot 120, formed in the tubular supporting member 74 of the head 
support 40, can be closed partly, which ensures that the conductor board 
sections 112 and 113 cannot inadvertently slide out of the duct 72. 
The end member 125 further comprises a rib 132 which extends radially of 
the pivotal axis 32. The rib 132 extends from the duct 72 in the head 
support 40 into the first slot portion 122 of the slot 120 which extends 
through the wall 121 of the tubular supporting member 74. The rib 132 has 
a rounded free end 133 by which the circumferential surface 134 of the 
tubular supporting member 74, i.e. of the second positioning cylinder 71 
is completed to a circularly cylindrical surface at the location of the 
first slot portion 122. In this way it is achieved that in spite of the 
presence of the slot 120 in the tubular supporting member 74 the 
circumferential surface of this member 74, at least at the location of the 
rib 132, is a substantially continuous circularly cylindrical surface, 
which in conjunction with the opening 98 in the positioning plate 99 
guarantees a correct mounting of the head support 40. 
In the present case the rib 132 extends up to the disc-shaped portion 130 
of the end member 125 and its portion between the cylindrical portion 129 
and the hollow cylindrical portion 131 is widened to interconnect the 
cylindrical portion 129 and the hollow cylindrical portion 131, which 
improves the overall stability of the end member 125. 
As appears in particular from FIG. 7, the end member 125 comprises two 
mutually parallel guide surfaces 135 and 136 for the conductor board 109, 
i.e. for the conductor board sections 112 and 113, at the location of the 
passage 126 for the flexible conductor board 109, between which guide 
surfaces the conductor board 109, i.e. its conductor board sections 112 
and 113, is passed with clearance. Thus, at the location where it 
traverses the head support the flexible conductor board 109 is protected 
simply against twisting when the magnetic-head unit 28 is pivoted about 
the pivotal axis 28. 
FIGS. 8 and 9 show a head support 40 of a magnetic-tape apparatus in 
accordance with a second embodiment of the invention. This head support 40 
has two slots 137 and 138 which are diametrically opposed relative to the 
pivotal axis 32 and which each extend in the same direction as the pivotal 
axis 32 over the whole dimension of the head support 40. The head support 
40 thus comprises two parts 139 and 140 which are separated from one 
another by the slots 137 and 138. For the passage of the conductor board 
sections 112 and 113 through the duct 72 of this head support 40 the two 
parts 139 and 140 of the head support 40 are separated from one another, 
after which the conductor board sections 112 and 113 are placed in the 
duct 72. Subsequently, the two parts 139 and 140 are reassembled to form 
the head support 40. To hold the two parts 139 and 140 together a ring 141 
and a ring 142 are respectively slid onto the supporting disc 41 and onto 
the second positioning cylinder 71 of the tubular supporting member 74 in 
the direction of the pivotal axis 32. The principal advantage of the head 
support 40 as shown in FIGS. 8 and 9 resides in the fact that in this case 
a flexible conductor board can be mounted in a very simple way and that 
the widened connecting portions of the flexible conductor board can have 
an arbitrary width. 
In the head support 40 shown in FIGS. 8 and 9, the supporting disc 41 has 
two bores 143 and 144 into which two fixing screws can be fitted to secure 
a suitably constructed magnetic-head unit to the supporting disc 41.