Electricity: motive power systems – With particular motor-driven load device – Tension-maintaining type of motor-control system
Reexamination Certificate
1999-01-25
2001-03-27
Masih, Karen (Department: 2837)
Electricity: motive power systems
With particular motor-driven load device
Tension-maintaining type of motor-control system
C318S007000, C318S034000, C318S063000, C318S068000, C318S008000, C318S080000
Reexamination Certificate
active
06208096
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a winding drive for a material in tape form. The invention proceeds from the winding device of a recorder for recording and/or reproducing signals by means of a recording medium in tape form and separate winding motors for driving the winding plates.
Such a winding drive is known, for example, from U.S. Pat. No. 3,906,299. For the purpose of braking the winding plates, particularly when switching over from winding mode into the stop mode, it is provided there during a rewinding operation to switch off the respectively pulling winding motor, also termed the motor on the winding-up side, and in this case to supply the respective other motor, also termed the motor on the unwinding side, with field current in such a way that the transport of the recording medium is braked and finally comes to a standstill, an evaluation circuit ensuring that the field current is switched off in good time so that no reverse movement can occur. The EMF generated in the respectively idling motor on the winding-up side serves as criterion in this case.
During a braking operation, such braking devices exert a uniform pulling action on the recording medium. Because of different mass distribution in the recording medium on the winding plates, however, it is possible for an indeterminate braking characteristic and thus for different braking distances and braking times to occur.
SUMMARY OF THE INVENTION
It is therefore the object of the invention to specify a method for driving such a winding device with an improved braking behaviour.
The invention relates to a method for controlling the drive of an appliance for transporting a recording medium in tape form, having two separate winding motors, in which the winding device is braked by means of stepwise controlling the two winding motors. The method comprises the steps of measuring respective instantaneous rotary movement of the two winding motors, comparing each respective measured instantaneous rotary movement with a desired value, deriving signals from both winding motors representative of differences between measured instantaneous values and the respective desired values, controlling the energization of each winding motor as a function of a sequence of paired reference values corresponding to respective rotational speed values, and progressing to a subsequent pair of reference values as soon as the rotational speed and assigned reference value of the respective winding motor correspond to one another.
A further object of the invention consists in specifying a winding device of the aforementioned type having an improved braking behaviour.
The invention is based on the idea configuring a winding device with separate winding motors to be capable of open-loop control and/or closed-loop control in such a way that—particularly at the end of a search or rewind operation—braking operations can take place in any defined fashion with respect to the braking time or a target position.
It is preferred to use servo units constructed as open-loop and/or closed-loop devices for driving the winding motors, with the result that it is possible in principle to dispense with driving the recording medium by means of a capstan and capstan idler, something which is otherwise customary when operating a recorder to record and/or reproduce. In accordance with the invention, these servo units are configured in such a way that they can advantageously be used for open-loop control and/or closed-loop control of the drive of the winding motor even during a braking operation. Developments and further advantages emerge from the following description.
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Search Report for German Patent Appln. No. 198 07 088.8.
Search Report for EPO Application No. 99101681.7-2210.
Mahr Peter
Oldermann Klaus
Deutsche Thomson-Brandt GmbH
Laks Joseph J.
Masih Karen
Sragow Daniel E.
Tripoli Joseph S.
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