Dynamic magnetic information storage or retrieval – Automatic control of a recorder mechanism
Reexamination Certificate
2000-06-19
2003-07-22
Hudspeth, David (Department: 2651)
Dynamic magnetic information storage or retrieval
Automatic control of a recorder mechanism
Reexamination Certificate
active
06597527
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a library apparatus of a composite type magnetic tape apparatus or the like and in particular, to an improvement of a data storage medium transportation unit for selecting a data storage medium from a plurality of data storage media stored in a data storage medium container and carrying the selected data storage medium to a read/write block or returning a data storage medium from the read/write block to the data storage medium container.
2. Description of the Related Arts
There is a known configuration of the data storage medium transportation unit for holding a data storage medium between the data storage medium container and the rear/write block. For example, a data storage medium is guided by a guide rail and transported by a timing belt and a screw type feed mechanism.
FIG. 7
is a conceptual representation of such a configuration. This is an example of composite type magnetic tape apparatus in which a magnetic tape cartridge is used as the data storage medium.
The composite type magnetic tape apparatus
100
shown in
FIG. 7
includes a data storage medium container
102
for storing a plurality of magnetic tape cartridges
101
, a read/write block
103
for reading and writing a data from/to the magnetic tape cartridge
101
, and a data storage medium transportation unit
119
.
The data storage medium transportation unit
119
includes: a data storage medium holding block
104
for which reciprocally moves with a magnetic tape cartridge
101
between the data storage medium container
102
and the read/write block
103
; a power transmission mechanism
105
for vertically driving the data storage medium holding block
104
; and a motor
106
.
The power transmission mechanism
105
includes: a guide rod
107
for vertically guiding the data storage medium holding block
104
; a driven pulley
108
rotatably attached to the top of the guide rod
107
; a drive pulley
109
fixed to a shaft of the motor
106
, and a timing belt
110
extending between the pulleys
108
and
109
so as to surround the pulleys
108
and
109
. A portion of the timing belt
110
is fixed to the data storage medium holding block
104
.
Accordingly, when this motor
106
is driven, the timing belt
110
is rotated and the data storage medium holding block
104
fixed to this timing belt
110
is raised or lowered along the guide rod
107
according to the rotation direction of the motor
106
, so that the data storage medium holding block
104
moves between the data storage medium container
102
and the read/write block
103
.
The data storage medium holding block
104
has a pickup mechanism (not depicted) for taking out a magnetic tape cartridge
101
from the data storage medium container
102
and the read/write block
103
or remounting the magnetic tape cartridge
101
, so that the magnetic tape cartridge
101
is taken out or remounted between the data storage medium container
102
or the read/write block
103
and the data storage medium holding block
104
.
The data storage medium container
102
has a plurality of layered cells
111
layered in a vertical direction. In order to pass the magnetic tape cartridge
101
horizontally between a cell and the data storage medium holding block
104
, the data storage medium holding block
104
should be accurately positioned to match the height of each of the cells
111
.
For this, in the conventional composite type magnetic tape apparatus
100
, the motor
106
serving as a drive source of the data storage medium holding block
104
has been constituted by an expensive servo motor, and a complicated control unit has been used for performing a feed back control of respective loops concerning the position and the speed.
FIG. 8
shows a concept of a general servo control. A reference symbol
112
represents a rotation-shift instruction. A microprocessor in a control unit performs pulse assignment according to a predetermined speed pattern
113
and outputs a rotation-shift instruction, i.e., a substantial rotation speed instruction for each pulse assignment cycle. Moreover, each time the microprocessor outputs the rotation-shift instruction, a value of the current rotation-shift instruction is deleted from a target value of the rotation shift amount stored in an assignment amount storage register, so as to determine a final rotation shift amount. That is, the pulse assignment processing is complete when the value of the assignment amount storage register has become zero.
The rotation-shift instruction
112
which is output from the control unit is added, for each processing cycle, to an accumulation counter
114
, and a return pulse from a pulse encoder
115
of the motor
106
, i.e., a feed back value of an actual rotation-shift amount of the motor
106
is deleted from the accumulation counter
114
, so that a current value of the accumulation counter
114
is fed as a rotation speed instruction according to a rotation-shift deviation to an D/A converter
116
. Accordingly, the motor
106
delays to follow the rotation-shift instruction
112
and the rotation-shift position deviation increases, which in turn increases the current value of the accumulation counter
114
and the value of the speed instruction. Moreover, when the rotation-shift deviation has become zero, the value the speed instruction also becomes zero, and the motor
106
retains its rotation position.
Moreover, the rotation speed instruction which is output from the D/A converter
116
is deleted by an output value of a tachogenerator
117
of the motor
106
, i.e., the actual rotation speed of the motor
106
, and the resultant value is fed as a torque instruction according to the rotation speed deviation, to a servo control circuit
118
. Accordingly, if the motor
106
delays to follow the rotation speed instruction to increase the rotation speed deviation, the torque instruction fed to the servo control circuit
118
is also increased. Moreover, when the rotation speed deviation has become zero, the torque instruction also becomes zero, the motor
106
retains its rotation position.
The servo control circuit
118
fed with the torque instruction controls the motor
106
by power amplitude processing or the like, and vertically drives the data storage medium holding block
104
as a mechanical load via the power transmission mechanism
105
.
Such a servo control enables to obtain a stable drive speed of the data storage medium holding block
104
with a high positioning accuracy. However, such a servo control requires peripheral apparatuses including the accumulation counter
114
, the D/A converter
116
, the servo control circuit
118
, and the tachogenerator
117
. That is, the production cost is increased. Moreover, in order to perform pulse assignment, the processing of the microprocessor should be performed as multi task, which increases the load of the microprocessor itself.
In order to eliminate these defects, the applicant of the present invention has suggested a data carrier loader as Japanese Patent Publication 10-366906, in which a protrusion of a data storage medium holding block is engaged with a rotary shaft having a helical groove on its circumferential portion, so that the data storage medium holding block is fed in the shaft axis direction.
The rotary shaft of this data carrier loader has a lead (distance advancing in the axis direction) zero portion as a flat portion for positioning, i.e., an interval where the position of the data storage medium holding block is not changed even if the rotary shaft is rotated, so that the positioning of the data storage medium holding block can be accurately performed even if the rotation position of the rotary shaft is not accurate. Thus, control is simplified and the positioning accuracy is increased.
The data carrier loader of Japanese Patent Publication 10-366906 can obtain a final positioning of a data storage medium holding block with a high accuracy even with rough control, and there is no need of measuring the rotation positi
NEC Corporation
Tzeng Fred F.
LandOfFree
Data storage medium transportation unit does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Data storage medium transportation unit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Data storage medium transportation unit will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3099663