Arrangement for cleaning a magnetic head in a magnetic tape recorder

For cleaning a magnetic head in a magnetic tape recorder, the cassette is provided with a cleaning device and is inserted in the magnetic tape recorder instead of a magnetic tape cassette. The cleaning device contains a cleaning element located at a carrier, the cleaning element pressing against the front side of the magnetic head instead of the magnetic tape and converting a rotary motion of a drive arrangement which normally drives the magnetic tape into a reciprocating motion and, under given conditions, simultaneously converting the rotary motion into a pivoting or rotational motion of the cleaning element relative to the magnetic head. The tape drive capstan of the magnetic tape recorder preferably serves a drive arrangement and the carrier is driven via an eccentric shaft which may be inclined relative to its rotational axis and via a worm gearing driven by the tape drive capstan.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an arrangement for cleaning a magnetic 
head in a magnetic tape recorder using a cassette provided with a cleaning 
device, the cassette being introduced into the magnetic tape recorder 
instead of a cassette provided with a magnetic tape, and being driven by a 
drive arrangement of the recorder. 
2. Description of the Prior Art 
It is already generally known in the art to employ a cassette for cleaning 
a magnetic head in a magnetic tape recorder, the cassette being inserted 
into the magnetic tape recorder instead of a cassette which is provided 
with magnetic tape. Instead of the magnetic tape, these cassettes contain 
a cleaning tape having a rough surface, the cleaning tape being driven in 
the same manner as the magnetic tape by way of the tape drive capstan 
and/or via the tape winding. 
Given the utilization of such a cassette, the cleaning therefore occurs in 
the running direction of the magnetic tape. Given frequent operation of 
the magnetic tape recorder, however, there is a danger that the magnetic 
tape will form countersinks on the magnetic head which can lead to slight 
depressions at the front side of the magnetic head in the region of the 
magnetic tape. Since the cleaning tapes comprise a rough surface, these 
depressions are further intensified by the cleaning tape. 
U.S. Pat. No. 4,272,796, fully incorporated herein by this reference, 
discloses an arrangement for cleaning a magnetic head in a magnetic tape 
recorder wherein a cleaning device is provided in a cassette. The cleaning 
device is composed of an eccentric arrangement which is driven by the 
drive arrangement of the magnetic tape recorder which drives the tape 
reel. A cleaning element executes a reciprocating motion in the moving 
direction of the magnetic tape. In a further embodiment, a wedge is 
provided at a drive wheel, the wedge executing a motion of the cleaning 
element perpendicular to the moving direction of the magnetic tape. 
A further arrangement for cleaning a magnetic head in a magnetic tape 
recorder is disclosed in the Japanese patent application No. 50-93774 
(Kokai No. 52-18306), also fully incorporated herein by this reference. 
Therein, also, a cleaning element located at a lever is driven in a 
cassette by a drive wheel and is moved perpendicular to the moving 
direction of the magnetic tape. The drive wheel comprises a wave-shaped 
depression at its circumference. 
SUMMARY OF THE INVENTION 
The object of the present invention is to provide a further arrangement for 
cleaning a magnetic head in a magnetic tape recorder, the arrangement 
guaranteeing a reliable cleaning of the magnetic head and nonetheless 
requires a relatively low expense. 
The above object is achieved in an arrangement for cleaning a magnetic head 
in a magnetic tape recorder, using a cassette provided with a cleaning 
device, the cassette being introduced into the magnetic tape recorder in 
place of a normal magnetic tape cassette and being driven by a drive 
arrangement of the tape recorder, and is particularly characterized in 
that the cleaning device contains an eccentric arrangement driven by the 
drive arrangement of the tape recorder, the eccentric arrangement 
converting the rotational motion of the drive arrangement into a 
reciprocating motion of a cleaning element of the cleaning device relative 
to the magnetic head and perpendicular to the moving direction of a 
magnetic tape. 
The arrangement is further particularly characterized in that the cleaning 
device contains an eccentric arrangement driven by the drive arrangement 
of the magnetic tape recorder, the eccentric arrangement converting the 
rotational motion of the drive arrangement into a pivoting motion of the 
cleaning element relative to the magnetic head. 
The cassette of the present invention has the advantage that it is 
versatily useable and comprises extremely good cleaning properties since 
the cleaning element executes a reciprocating motion relative to the 
magnetic head, which differs from the running direction of the magnetic 
tape. Deposits on the magnetic head which collect behind the 
irregularities of the magnetic head are therefore also covered. Moreover, 
the formation of depressions in the region of the magnetic tape is not 
additionally promoted when cleaning the magnetic head. 
Particularly good cleaning properties of the arrangement are achieved when, 
instead of the reciprocating motion of the cleaning element perpendicular 
to the direction of motion of the magnetic tape or in addition to this 
reciprocating motion, a pivoting motion of the cleaning element is 
executed. This pivoting motion can also be interpreted as a partial 
rotational motion or an oscillatory motion in the plane of the magnetic 
tape. 
According to a preferred embodiment of the invention, the eccentric 
arrangement contains an eccentric shaft which is driven via a worm gear 
and a drive pinion and which is at least partially embraced by a carrier 
provided with a cleaning element. 
The pivoting motion of the cleaning element is achieved in that the 
eccentric shaft is fashioned in an inclined manner. For example, the ends 
of the eccentric shaft can be turned relative to one another by an angle 
of roughly 60.degree.. 
The worm gearing is preferably formed of a worm driven by a drive pinion 
and of a worm wheel located on a shaft of the eccentric arrangement. The 
drive pinion is thereby driven by the tape drive capstan normally moving a 
magnetic tape or is driven by a drive arrangement of the magnetic tape 
recorder turning a reel with the magnetic tape. In the former case, the 
drive pinion is advantageously fashioned as a friction wheel. 
In order to integrate the cleaning device in a cassette, it is favorable 
when the drive pinion or drive wheel is immediately connected to a worm of 
the worm gearing and comprises a depression for an appertaining worm 
wheel. 
The bearing of the carrier provided with the cleaning element 
advantageously occurs upon use of a spherical portion connected to the 
carrier, the spherical portion resting on a corresponding ball socket 
connected to the cassette and being arranged at that end of the cassette 
lying opposite the cleaning element. 
In addition to the reciprocating motion perpendicular to the direction of 
movement of the magnetic tape and, given conditions, in addition to the 
pivoting motion, a motion of the cleaning element in the direction of the 
magnetic tape can also be executed. In case this is desirable, a guide pin 
is advantageously provided, the guide pin guiding the carrier via a 
corresponding recess during its reciprocating motion perpendicular to the 
direction of movement of the magnetic tape or during its pivoting motion. 
The cleaning element is advantageously designed as a replaceable element. 
To this end, the cassette contains an additional opening in its cover. The 
cleaning element is located on a strip. This strip can be dilatably 
fashioned and can be replaced in common with the cleaning element. It 
proves advantageous, however, to arrange the cleaning element on a strip 
which is secured at the carrier in a pivotal and logical fashion. However, 
it also proves advantageous to arrange the cleaning element at a strip 
which is secured to the carrier in a pivotal and latchable fashion. The 
cleaning element is preferably provided with a longitudinal opening by way 
of which it can be interchangeably slipped onto the strip. The cleaning 
element can therefore be replaced in a very simple manner and, for 
example, can be turned over after a prescribed time interval so that the 
rear side can also be employed for cleaning. 
For the purpose of replacement, the strip is preferably provided with an 
articulation at its one end, the articulation being secured to the 
carrier, and is provided with a catch nose at its other end, the catch 
nose being latchable in the carrier. When the carrier is fashioned with 
plastic, the articulation is preferably fashioned as a film hinge. 
A particularly advantageous cleaning effect occurs when the cleaning 
element is located not parallel, but rather inclined, relative to the 
front edge of the cassette.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to FIG. 1, a cassette 1 has outer dimensions which largely 
coincide with those of a commercially available cassette provided with 
magnetic tape which is also known as a 1/4" cartridge. After the cassette 
1 has been introduced into a corresponding magnetic tape recorder 
comprising a magnetic head 2 and a tape capstan drive 3 normally provided 
for the drive of the magnetic tape, a cleaning element 4 of a cleaning 
device contained in the cassette presses against the front side of the 
magnetic head 2. A drive wheel 5 of the cassette 1 is fashioned, for 
example, as a friction wheel and has a coating of rubber on its periphery. 
A worm 6 is located on the shaft of the drive wheel 5, the worm 6, for 
example, forming a structural unit with the drive wheel 5. The worm 6 is a 
portion of a worm gearing and is assigned to a worm wheel 7 located on an 
eccentric arrangement 8. The eccentric arrangement 8 is formed of a shaft 
10 seated in two bearings 9 and an eccentric shaft 11. The worm wheel 7 is 
located on the shaft 10. 
The eccentric shaft 11 is embraced by a carrier, first by its supporting 
surface and second by a lift 13. The cleaning element 4 is located at the 
carrier 12, at the front side thereof, the cleaning element 4 being 
fashioned, for example, felt-like and pillow-shaped and can be saturated 
with a cleaning fluid. The cleaning element 4 is located on a preferably 
dilatable strip 14 and can, for example, be replaced together with the 
strip 14. To this end, the cover of the cassette 1 comprises an opening at 
its upper side in the corresponding region. The rear portion of the 
carrier 11 is movably seated at the cassette, in particular by way of a 
spherical portion 15 which is movably seated in a corresponding ball 
socket 16 connected to the base plate of the cassette 1 and which is held 
in the ball socket 16 by way of the pin 17 located at the cover of the 
cassette 1. 
Given a rotational motion of the tape drive capstan 3 in one of the two 
rotational senses, the drive wheel 5 and the worm 6 are likewise placed in 
rotation. The rotational motion is transmitted onto the eccentric 
arrangement 8 by way of the worm gearing formed of the worm 6 and the worm 
wheel 7 and, due to the eccentric shaft 11 which is embraced by the 
carrier 12, the carrier 12 executes a reciprocating motion perpendicular 
to the direction of motion of the magnetic tape relative to the magnetic 
head 2 in order to clean the latter. In case the magnetic head 2 is 
fashioned to be positionable, a motion, preferably a slow motion of the 
magnetic head 2 can be additionally executed perpendicular to the 
direction of movement of a magnetic tape. The cleaning element 4 thereby 
presses lightly against the magnetic head 2 and can be saturated with a 
cleaning fluid for cleaning. 
It is also possible to drive the cleaning device by way of a drive 
arrangement of the magnetic tape recorder which is normally provided for 
driving one or both reel of the magnetic tape in the cassette. Further, it 
is possible to execute a reciprocating motion in the direction of movement 
of the magnetic tape in addition to the reciprocating motion perpendicular 
to the direction of ovement of a magnetic tape. 
The second embodiment of the invention illustrated in FIG. 2 largely 
coincides with the first embodiment. A significant difference, however, is 
that the eccentric shaft 11 is not arranged parallel to the shaft 10, but 
is located inclined relative thereto. For example, the ends of the 
eccentric shaft 11 are rotated relative to one another in a range of from 
45.degree. through 75.degree., preferably 60.degree.. Further differences 
with respect to the first embodiment are also that a further bearing 9 is 
provided, and that the carrier 12 comprises an opening 19 through which a 
guide pin 18 projects perpendicularly to the floor of the cssette. The 
guide pin 18 guides the carrier 12 during its oscillatory motion and, 
under given conditions, during its reciprocating motion and the opening 19 
is fashioned such that these motions are possible. Finally, the second 
embodiment also differs in that the strip 14 with the cleaning element 4 
is fashioned so that it, can be hinged out in order to replace the 
cleaning element when the cleaning element is fashioned to be pluggable 
onto the strip 14. 
The plan view of the cassette 1 of the second embodiment is shown in FIG. 3 
which illustrates the eccentric arrangement 8 which is composed of a shaft 
10, the worm wheel 7 and the eccentric shaft 11. The eccentric arrangement 
8 is rotatably seated in three bearings 9 and is driven via a drive wheel 
5, and the worm 6 connected thereto, via the worm wheel 7. The eccentric 
shaft 11 is located inclined relative to the axis of the shaft 10 and, 
upon rotation of the eccentric arrangement 8, the carrier 12 is placed in 
reciprocating motion and, simultaneously, into the oscillatory motion 
which can also be interpreted as a pivoting motion or a partial rotary 
motion. In other words, as is clear from FIGS. 2-4, the cleaning element 4 
rotates about an axis which extends from the cleaning element 4 in the 
general direction of pin 17, while the axis itself can be said to 
simultaneously translate back and forth in a complex motion between an 
extreme left and an extreme right position, i.e., in an oscillatory path, 
such that the translation of the axis about which the cleaning element 4 
rotates, and therefore the translation of the rotating element 4 itself, 
has components both perpendicular to and parallel to the direction of tape 
travel. At its rear end, the carrier 12 is seated by the spherical part 15 
and embraces the eccentric shaft 11 at the one side, for example, at the 
upper side, by way of the lateral seating surfaces and embraces the shaft 
11 at the other side, for example, the underside, by way of the lip 13. 
The pivotal strip 14 may be seen at the front side of the carrier, the 
strip 14 being secured to the carrier via an articulation 21. When the 
carrier is fashioned of plastic, the articulation is formed, for example, 
as a film hinge. At its other end, the strip 14 comprises a catch nose 22 
which can be inserted into a corresponding opening 23 of the carrier when 
the strip 14 is in its operating position. The strip 14 is slipped over 
the cleaning element which comprises a longitudinal opening. The cleaning 
element 4 is interchangeably secured on the strip 14 and, when the latter 
is hinged out, can be replaced or turned in a simple manner, so that it 
can be used from both sides. The cleaning element 4 is constructed 
pillow-like or felt-like and can be saturated with the cleaning fluid. 
In the illustration of FIG. 4, the eccentric arrangement 8 is shown as a 
discrete component. As already set forth, it is composed of a shaft 10, 
the worm wheel 7 and of the eccentric shaft 11. Sections along the lines 
A--A and B--B are shown at both sides in FIG. 4, it proceeding therefrom 
that the ends of the eccentric shaft 11 are rotated relative to one 
another by an angle of, for example, 60.degree.. 
In the section through the carrier shown in FIG. 5, the spherical portion 
15 may be seen at the rear end thereof. Also visible are the recess 19 for 
the guide pin 18 and the lip 13 which embraces the eccentric shaft 11 on 
the underside of the carrier. The opening 23 for the catch nose 22 of the 
strip 14 is shown at the front end of the carrier 12. 
The drive wheel 5 illustrated in FIG. 6 forms a structural unit with the 
worm 6. The drive wheel 5 is fashioned as a friction wheel and, at its 
underside at the region of the worm 6, comprises a depression 20 for the 
worm wheel 7 in order to achieve a low structural height of the worm 
gearing. 
Although I have described my invention by reference to particular 
illustrative embodiments thereof, many changes and modifications of the 
invention may become apparent to those skillediin the art without 
departing from the spirit and scope of the invention. I therefore intend 
to include within the patent warranted hereon all such changes and 
modifications as may reasonably and properly be included within the scope 
of my contribution to the art.