Printing – Processes – Condition responsive
Reexamination Certificate
2000-03-31
2002-06-11
Hirshfeld, Andrew H. (Department: 2854)
Printing
Processes
Condition responsive
C101S216000
Reexamination Certificate
active
06401620
ABSTRACT:
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The invention relates to a method for compensating torsional vibrations of a printing machine by introducing torques which compensate the vibration excitation. The invention relates, furthermore, to apparatus for performing this method, with at least one device for introducing torques into the drive train of a printing machine for compensating vibration excitations.
Various types of vibrations occur in printing machines and influence print quality. Predominent originating sources of vibrations are cylinder channels or gaps and also sheet transfer elements and other discontinuously operating machine elements. This leads, on the one hand, to bending vibrations in rollers and cylinders, but also to torsional vibrations of cylinders or drums. The latter are propagated via gearwheels of the gearwheel train. The occurring torsional vibrations can be described by a number of characteristic forms and amplitude/time profiles assigned thereto. In this regard, the characteristic forms reproduce a local amplitude distribution. They are printing machine properties independent of the excitation, and they depend upon the number of printing units and upon the type of construction of the machine. Such machine vibrations can be controlled by passive and active accessory systems.
The published European Patent Document EP 0 592 850 B1 discloses a device and a method providing active actuating elements, for example motors, on individual cylinders in order to activate the motors via measurements and controls so that regulating forces for damping the vibrations are generated. This is not an originally targeted counterstrategy against vibrations in the machine-typical characteristic forms, but rather, the vibrations which occur are measured and are thereafter controlled at the measurement location. In this way, compensation is not timely optimized, however, and requires a great outlay for regulating purposes, the risk being that regulation either has too great a time delay or itself causes vibrations. Nor are the compensating measures optimized with regard to the location thereof. If only a single actuating member is provided, it may lie at the zero crossing of a characteristic form of the printing machine, and, at this point, neither a value for the vibration in this characteristic form is determined, nor can countertorques be introduced thereat. If the compensating measure takes place at a location of low amplitudes of the characteristic form, correspondingly higher torques are required. In any case, a great outlay in sensor and regulation technology is required.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a method and a device of the type mentioned in the introduction hereto, namely, for compensating torsional vibrations of a printing machine by introducing torques which compensate the vibration excitation, so that optimum compensation of torsional vibrations of a printing machine is achieved at the least possible expense or outlay.
With the foregoing and other objects in view, there is provided, in accordance with one aspect of the invention, a method for compensating torsional vibrations of a printing machine by introducing torques which compensate vibration excitation, which comprises determining at least one characteristic form of a printing machine for at least one location on a drive train of the printing machine, determining and storing at least one respective countertorque for compensating the torques which excite vibration in a characteristic form at a location whereat the characteristic form is not zero, and applying the at least one countertorque at the corresponding location so that the vibration is maximally reduced due to the application of the at least one countertorque.
In accordance with another mode, the method of the invention includes selecting the location for applying the at least one countertorque thereat because it is a location at which the amplitudes of the vibration in the characteristic form are high.
In accordance with a further mode, the method of the invention includes using a plurality of characteristic forms of a printing machine for determining countertorques.
In accordance with an added mode, the method of the invention includes determining the countertorques for an average rotational speed of the machine.
In accordance with an additional mode, the method of the invention includes determining the countertorques for various rotational speeds of the machine.
In accordance with yet another mode, the method of the invention includes, for changing the phase relationship of the required countertorques, introducing into the drive train at least two partial torques, the phase relationship of which is adjusted correspondingly.
In accordance with yet a further mode, the method of the invention includes, for a printing machine operating in a verso printing mode, determining the countertorques separately for each machine region adjacent to a reversing device, and separately applying the corresponding countertorques for each machine region.
In accordance with another aspect of the invention, there is provided an apparatus for performing a method of compensating torsion vibrations by introducing torques which compensate vibration excitation, comprising at least one device for introducing torques into a drive train of a printing machine for compensating vibration excitations, said at least one device being disposed at a location of the drive train at which a characteristic form having an excitation which is to be compensated is not zero, the torque for compensating the torques which excite vibration in the characteristic form being introducible to said at least one device, and said at least one device being able to impart a countertorque to said drive train.
In accordance with another feature of the invention, the at least one device is disposed at a location on the drive train at which amplitudes of the characteristic form are high.
In accordance with a further feature of the invention, the apparatus includes further devices for applying further countertorques, the further countertorques serving for compensating torques which excite vibration in further characteristic forms.
In accordance with an added feature of the invention, the at least one device is constructed for storing and retrieving countertorques for various machine parameters.
In accordance with an additional feature of the invention, the apparatus is in combination with a printing machine having at least one reversing device, each machine region adjacent the reversing device having the countertorque-applying device assigned thereto.
In accordance with yet another feature of the combination, the printing machine is convertible between recto printing and verso printing mode, and during such a conversion, the countertorque-applying device is adjustable therewith for the machine region adjusted in angular relationship thereof to the rest of the machine, so that the countertorques are applicable in a correct phase relationship.
In accordance with yet a further feature of the combination, the device for introducing torques is a motor.
In accordance with yet an added feature of the combination, the device for introducing torques comprises a hydraulic application of torque.
In accordance with yet an additional feature of the invention, the combination includes a control for receiving an entry therein of countertorques for various rotational speeds of the machine.
In accordance with an alternative feature of the combination, the device for introducing torques is at least one cam mechanism.
In accordance with still another feature of the combination, the cam mechanism has a cam disk fixedly connected to a gearwheel of the drive train, and a roller is included for applying a force to the cam mechanism.
In accordance with still a further feature of the combination, the cam mechanism has a stationary cam disk, and there is included a roller rotatable by an arm connected to a cylinder journal for applying a force to the cam mechanism.
In ac
Buck Bernhard
Merz Michael
Greenberg Laurence A.
Heidelberger Druckmaschinen AG
Hirshfeld Andrew H.
Locher Ralph E.
Nolan, Jr. Charles H.
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