Winding – tensioning – or guiding – Unwinding and rewinding a machine convertible information... – Cartridge system
Reexamination Certificate
2002-03-20
2004-06-08
Rivera, William A. (Department: 3653)
Winding, tensioning, or guiding
Unwinding and rewinding a machine convertible information...
Cartridge system
C242S345200, C242S348000
Reexamination Certificate
active
06745968
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application is a National Stage Application of International Application No. PCT/EP00/06157, filed Jul. 4, 2001. Further, the present application claims priority under 35 U.S.C. § 119 of German Patent Application No. 199 30 802.0 filed on Jul. 3, 1999.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a cartridge for magnetic recording media in tape form, preferably a single-reel cartridge for data tapes having a multi-part braking system.
2. Discussion of Background Information
Cartridges of this type comprise at least a housing which, with the exception of one corner, is of an angular design. The housing has two housing parts with bottom, top and side walls and the housing parts are welded or screwed to one another. A tape reel is provided which uses a hub. Protruding from the ends of the hub are radial upper and lower flanges. The hub base has the driving and braking serration, and a magnetic tape (not shown) is wound up on the hub. Provided at the free end of the hub is a guide element. With the aid of the guide element, the magnetic tape is led to the winding-up reel and wound up on the latter. A reel brake is also included, which is connected on its upper side via connecting elements to the housing top wall in an axially displaceable manner. However, it is secured against twisting and radial positional changes. The serration engages in the braking serration of the tape reel and thus also secures the tape reel against twisting and, by the action of the spring, simultaneously presses against the lower housing part when the driving hub of the equipment is not in engagement.
The reel brake
1
, which is generally conventional in the case of single-reel cartridges, is released directly, as shown in FIG.
1
and
FIG. 2
, on the equipment side by a pin
2
having a wear-resistant surface. Since the surface of this pin
2
protrudes somewhat above the plane of the serration
6
of the driving hub or the winding pin
8
, the reel brake
1
is initially lifted against the force of the spring
12
by the winding pin
8
during loading of the cartridge into the drive unit. Only thereafter does the force acting between the magnet
9
on the equipment side and the metal plate
10
recessed into the hub base of the tape reel
3
cause the serration
6
of the winding pin
8
to engage in the driving serration
5
of the tape reel
3
and cause the tape reel
3
to be lifted from the lower wall of the housing
7
out of its first position, (i.e., the rest position shown in FIG.
1
), into its second position, (i.e., the operating position), which is shown in FIG.
2
.
EP 0 284 687 A describes a single-reel cartridge with improved centering of the reel brake relative to the tape reel. The ribs or projections are mounted about the cylindrical inner circumference of the tape reel hub, on which the exterior diameter of the disk-shaped center of the reel brake is guided, both when assembling the cartridge and when easing the reel brake during operation.
This type of braking system has, among other disadvantages, the disadvantage that both the required travel for releasing the reel brake and the travel for lifting the tape reel out of its first position into its second position are added to each other and consequently restrict the lower limit of the cassette height and overall equipment height.
EP 0 926 676 A describes a single-reel cartridge with two-part braking system, with the first part of the braking system being operated by the equipment-side driving hub, and having on the circumference of its disk-shaped central portion an annular protrusion pointing in the direction of equipment-side driving hub, which protrusion extends into a circular groove located in the area of the tape reel hub opening, and with the circumferential circular protrusion overlapping the circumferential circular groove even with the travel of the braking system necessary to release the reel brake, and with the cartridge thus being protected from dust and dirt entering through the reel hub opening.
However, technical development has for some time required cartridges with an every greater storage density and at the same time every smaller outer housing dimensions.
A braking system which meets this requirement is conventionally known. This system is represented in FIG.
3
and proposes a two-part braking system, the first element corresponding to the conventional reel brake
1
and the second element representing a driver disk
4
. The driver disk
4
includes a thin plate
11
, which is axially displaceable within the hub
13
and has three feet
14
which are evenly distributed around the circumference and protrude through the hub base of the tape reel
3
, through clearances
16
in the region of the driving serration
5
. The releasing of the reel brake
1
from the tape reel
3
in the operating position (i.e., the second position) thus takes place by means of this driver disk
4
, which is lifted to the same extent in the tape reel as the serration
6
of the driving hub
8
engaging into the driving serration
5
of the tape reel
3
when the forces of the magnet
9
act on the metal plate
10
fastened in the tape reel
3
.
A disadvantage of this arrangement is that it only functions satisfactorily if the tolerances between the driver disk
4
and clearances
16
of the tape reel
3
are adequate in the corresponding regions. This results in both radial and tangential backlash and consequently in moveability or movement between the driver disk
4
and tape reel
3
.
Since the tape reel
3
constantly undergoes changes of direction and accelerations during operation, forces of inertia act on the driver disk
4
, making the driver disk
4
run eccentrically within the tolerances in the tape reel
3
.
To be regarded as another disadvantage of the known cartridges is the configuration of the contact surfaces between the reel brake
1
and driver disk
4
. Adequately precise concentric running of the tape reel
3
can be achieved only if the reference receiving openings
17
for positional fixing of the cartridge in the equipment and the centering on axis A of the tape reel
3
with respect to the centering of the reel brake
1
lie within relatively small tolerances. For example, it is possible that, owing to the radial moveability or movement of the driver disk
4
within the tape reel
3
, the contact surface of the reel brake
1
can over time work into the surface of the driver disk
4
at various points, which may be further exacerbated by differences in the positional fixing when playing back the magnetic-tape cartridge on different equipment. This may result in eccentric centerings between the reel brake
1
and driver disk
4
, which bring about undesired radial movement of one or both parts
1
and
4
in their guides during each revolution.
A further disadvantage of conventional braking systems is the fact that the reel brake
1
has a tendency to undergo wobbling movements if runout errors of the tape reel
3
, caused by tolerances originating both from the equipment and from the tape reel itself, coincide with correspondingly great backlash in the elements of the twist-preventing means of the reel brake
1
.
Furthermore, during the transfer of the force of the spring
12
by the reel brake
1
to the feet
14
arranged on the outer circumference of the plate
11
, the thin plate
11
of the driver disk
4
can bend and thus reduce the brake lifting-out path.
As a consequence of this, running noises and abrasion occur at the driving serration
6
and/or driver disk
4
and/or cartridge housing
7
.
Abrasion generally produces dropouts on the recording medium in tape form. Abrasion at the driver disk
4
and at the serration
5
causes dimensional changes at the parts concerned and, in an extreme form, may reduce the brake lifting-out path and consequently make the cartridge unable to function.
Since both running noises and abrasion cannot be accepted for high-quality digital data storage systems, the object was to improve
Hummel Edgar
Kuenstner Matthias
Schoettle Klaus
EMTEC Magnetics GmbH
Greenblum & Bernstein P.L.C.
Rivera William A.
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