Winding – tensioning – or guiding – Unwinding and rewinding a machine convertible information... – Cartridge system
Reexamination Certificate
2002-06-28
2003-12-02
Rivera, William A. (Department: 3654)
Winding, tensioning, or guiding
Unwinding and rewinding a machine convertible information...
Cartridge system
C242S348000, C360S096300
Reexamination Certificate
active
06655624
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a cartridge engaging mechanism for the engagement between a tape cartridge and a tape drive device when the tape cartridge is loaded into the tape drive device.
2. Description of the Related Art
A single reel cartridge magnetic tape is used as one of storage media for computers. The magnetic tape is wound around a reel while one end thereof is fixed to the core of the reel, and the reel is supported in a case of a cartridge so as to be rotatable relatively to the case. The other end of the magnetic tape is drawn out from the case of the cartridge followed by rotation of the reel.
When the cartridge is loaded in the magnetic tape drive device, the rotational driving force can be transmitted from the driving motor (reel motor) of the drive device to the reel of the cartridge by a cartridge engaging mechanism. In order to construct the cartridge engaging mechanism, a plane-type cartridge gear exposed to the outside from the outer surface of the case is equipped to the reel at the cartridge side, and a plane-type drive gear for receiving the rotational force transmitted from the reel motor is disposed at the drive device side, and the cartridge gear and the drive gear are disposed so as to come into contact with each other and separate from each other.
The cartridge is equipped with a reel lock mechanism for preventing the reel from being rotated relatively to the case of the cartridge when the cartridge is unloaded from the drive device (that is, the engagement of the cartridge engaging mechanism is canceled). With the reel lock mechanism, the reel can be prevented from being rotated relatively to the case of the cartridge under states other than the loading state of the cartridge in the drive device, thereby preventing rewinding of the magnetic tape and occurrence of slack of the magnetic tape.
The reel lock mechanism is designed so that brake is released only when the cartridge gear is engaged with the drive gear. In order to satisfy this operation, a movable member called as a lock pad which abuts against the gear tooth tops of the drive gear is secured to each portion at which some gear teeth are removed from the cartridge gear. The lock pad is disposed so as to be reciprocatively movable between an advance position at which the lock pad is projected forwardly from the gear surface and a retraction position at which the lock pad is retracted backwardly from the gear surface. The lock pad is forwardly urged to the advance position by a spring. The brake acts at the advance position, and the lock pad is backwardly moved to the retraction position against the urging force of the spring to release the brake. Therefore, the lock pad is required to have a proper reciprocative movement stroke.
FIG. 12
is a schematically partially cross-sectional view showing the drive gear and the cartridge gear of a conventional cartridge engaging mechanism as described above.
A cartridge gear
101
a
is designed in an annular form so as to surround the rotational center CL
1
extending in the up-and-down direction, and three lock pads
101
b
are disposed so as to be spaced at an equal angular interval in the circumferential direction of the cartridge gear
110
a.
Each lock pad
101
b
is movable in the up-and-down direction over a required stroke with the position shown in
FIG. 12
as the lower limit position. A non-tooth portion
101
e
at which three gear teeth of the cartridge gear
101
a
are removed is formed in the neighborhood of the formation position of each lock pad
101
b.
The drive gear
122
has such a shape that it is fit to the cartridge gear
101
a,
and it is designed in an annular form so as to surround the rotational center CL
2
extending in the up-and-down direction.
Each tooth top of the cartridge gear
101
a
is provided with a tapered portion having a gradually-lowered taper angle of &thgr;a in an area extending inwardly from each lock pad
101
b,
and each tooth top of the drive gear
122
is provided with a tapered portion having a gradually-lowered taper angle of &thgr;b in an area extending inwardly from the center of each lock pad
101
b
as shown in FIG.
12
. Accordingly, under the state that the cartridge gear
101
a
and the drive gear
122
are properly engaged with each other with the rotational centers CL
1
, CL
2
thereof being common to each other, the tooth tops of the drive gear
122
abut against and pushes the lock pads
101
b
at the highest position of the tooth tops, so that the lock pads
101
b
can be moved by a distance enough to release the brake.
However, if the precision of the positioning of the cartridge case to the drive device when the cartridge is loaded into the drive device and the positional precision of the cartridge gear to the cartridge case are not sufficient, there occurs a positional error between the cartridge gear
101
a
and the drive gear
122
as shown in FIG.
13
. As shown in
FIG. 13
, there is a case where the positional error described above occurs so that the positional error direction of the cartridge gear
101
a
with respect to the drive gear
122
is substantially coincident with the direction of the lock pad
101
b
relative to the rotational center CL
1
of the cartridge gear
101
a.
FIG. 14
is a cross-sectional view in the circumferential direction showing the neighborhood of the position corresponding to the lock pads
101
b
at the outermost peripheral position at which the tooth tops of the drive gear
122
are highest.
As is apparent from
FIG. 14
, when a slight inclination occurs between the rotational axis direction of the drive gear
122
and the rotational axis direction of the cartridge gear
101
a,
the tooth tops at both sides of each non-tooth portion
101
e
intrude in each portion having the largest tooth top pitch in the neighborhood of the outermost peripheral portion of the drive gear
122
. Firstly, this is because the tooth top pitch of the cartridge gear
101
a
is smaller than the tooth top pitch of the drive gear
122
within the cross section shown in
FIG. 14
, and secondly this is because the tooth tops of the drive gear
122
are formed to be highest in height in order to achieve a required lock pad movement stroke, so that the width W′ of the flat portion of each tooth top of the drive gear
122
is small and thus there is little margin in receiving the tooth tops of the cartridge gear
101
a
by the flat portions of the tooth tops of the drive gear
122
. Under such a situation, the relative rotation between both the gears is impossible, and thus it is impossible to properly engage both the gears with each other.
Therefore, in the conventional cartridge engaging mechanism, the permissible dimension for the error or displacement S′ between the rotational centers CL
1
, CL
2
of the gears which enables the proper engagement between both the gears is reduced, and thus it is required to enhance the precision of the positioning of the cartridge case to the drive device and also enhance the positional precision of the cartridge reel to the cartridge case. This is an obstacle to reduce the cost of the cartridge engaging mechanism and the cartridge and drive device.
SUMMARY OF THE INVENTION
An object of the present invention is to enhance the tolerance level of the positional error between a cartridge gear and a drive gear to be engaged with each other in a cartridge engaging mechanism.
Another object of the present invention is to enhance the tolerance level of the positional error between a cartridge gear and a drive gear to be engaged with each other in a cartridge engaging mechanism while keeping a required movement stroke of a lock pad of a reel lock mechanism.
In order to attain the above object, according to the present invention, there is provided a cartridge engaging mechanism for engaging a plane-type cartridge gear secured to a reel of a tape cartridge loaded in a tape drive device with a plate-type drive gear connected to a reel motor of the tape drive device, characterized in t
Rivera William A.
Young & Thompson
LandOfFree
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