Printing – Press part or attachment
Reexamination Certificate
1999-08-02
2001-06-19
Colilla, Daniel J. (Department: 2854)
Printing
Press part or attachment
C101S216000, C310S083000, C310S06700R
Reexamination Certificate
active
06247407
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a printing press drive system having at least one drive with an external-rotor motor, the rotor thereof being equipped with permanent magnets and assigned to at least one cylinder of the printing press for the drive of the one cylinder, the stator of the external-rotor motor containing the windings and being firmly connected to a side panel of the printing press.
Printing press drive systems heretofore known in the prior art are formed of a closed gear train at the drive side of the printing press, the gear train being driven by a drive motor via a reduction gear and a belt drive. In this regard, high torques must be transmitted over an input pinion, a corresponding outlay being necessary with very massive gearwheels. In addition, the drive motor requires considerable space, and high tension forces of the drive belt must be taken up by bearings. Belt disturbances result in impairment of the torque quality which can in turn reduce printing quality. Because the power is led in over the central pinion, this must take up the entire drive torque for the press. The high forces are a problem particularly for presses with many printing units, especially for presses with six to eight or more printing units which are necessary when special inks have to be used.
In order to remedy these problems, a drive system of the type mentioned at the introduction hereto was proposed in the published German Patent Document DE 195 30 283 A1 in which the gear train is replaced by individual drives. One of the proposed individual drives provides an external-rotor motor having a stator fixed to the inside of the side panel of the printing press. This stator lies inside the cylinder, and the rotor is connected with the inside surface of the cylinder. In this way it is possible to dispense with a gear train and central drive motor and thus avoid the foregoing problems associated therewith.
A disadvantage of this attempted solution is that the angular coordination of the cylinders is controlled only electronically. In the case of a malfunction, for example due to a power interruption, the angular coordination is lost and there is a danger of a collision of the gripper bars. A further disadvantage of this attempted solution is that the cylinders no longer have any free shaft ends at the drive side of the printing press. Thus, it is not possible to provide auxiliary gearwheels for preventing the aforementioned danger of collision, nor to provide sensors, tachometers or brakes.
It is also impossible to drive further cylinders or rollers from the individual drives. Thus a large number of separate drives are necessary, although fewer drives—often only one drive per printing unit—would represent an ideal solution. Waste heat from the motor fitted inside the cylinder is an additional problem. This type of waste heat interferes with the printing process for many cylinders, for example plate cylinders, blanket cylinders or impression cylinders.
2. Summary of the Invention
It is accordingly an object of the invention, therefore, to provide a printing press drive system that avoids the disadvantages of drive systems or drives of the prior art and the disadvantages of the proposed individual drives, and which, in particular, reduces the high torques and, thereby, represents a simple, efficient and functionally reliable concept which saves space and material.
With the foregoing and other objects in view, there is provided, in accordance with the invention, a printing press drive system comprising at least one drive having a motor with an external rotor equipped with permanent magnets, the one drive being assigned to at least one cylinder of the printing press for driving the cylinder, and with a stator provided with windings and firmly fixed to the side panel of the printing press, at least part of the drive system being implemented via a gear train, and the rotor having a gear rim at a perimeter thereof.
In accordance with another feature of the invention, the rotor is firmly connected to the cylinder.
In accordance with a further feature of the invention, the printing press includes additional drives with respective external rotor-motors, and the printing press has a plurality of printing units, each of the printing units having at least one of the drives with an external-rotor motor assigned thereto.
In accordance with an added feature of the invention, the at least one drive is assigned to a cylinder so that it is separated from cylinders having the greatest power demand through as few power transmission locations as possible.
In accordance with an additional feature of the invention, the stator is fixed directly to the outside of the side panel of the printing press.
In accordance with yet another feature of the invention, the rotor is connected directly to a cylinder shaft and has the shape of a pot embracing the stator from the outside.
In accordance with yet a further feature of the invention, the rotor is formed of high-energy magnetic materials with a minimum possible thickness in a circumferential region thereof.
In accordance with yet an added feature of the invention, the gear rim is supported on the rotor so as to enable the gear rim to be rotated and fixed in position.
In accordance with yet an additional feature of the invention, the printing press drive system includes a sensor assigned to the gear rim, the gear rim having gear teeth serving for the sensor as markings for determining the angular position of an appertaining cylinder.
In accordance with still another feature of the invention, the rotor has a braking surface disposed thereon, and a brake is assigned to the rotor.
In accordance with still a further feature of the invention, the gear rim is directly received in the gear train.
In accordance with still an added feature of the invention, the printing press has a plurality of cylinders, and the gear rim serves as a driving part of a compact gear transmission system for driving the cylinders.
In accordance with another feature of the invention, the compact gear transmission system is a planetary gear train.
In accordance with an alternate feature of the invention, the compact gear transmission system is a cyclic gear train.
In accordance with a further alternate feature of the invention, the compact gear transmission system is a harmonic drive gear train.
In accordance with an added alternate feature of the invention, the compact gear transmission system is a spur gear train.
In accordance with an additional feature of the invention, the printing press drive system includes a flowing medium for cooling the stator.
In accordance with a concomitant feature of the invention, the printing press drive system includes a controller for discontinuously feeding power to at least one of the drives in a manner for counteracting a generation of vibrations due to discontinuous power consumption.
The invention makes it possible to avoid both the disadvantages of drives of the prior art and the disadvantages of the individual drives proposed in the published German Patent Document DE 195 30 283 A1. In particular, the torques arising in the gearwheels are considerably reduced, so that they and the bearings can be made smaller, thereby ecomizing on material, costs and space requirements. The particular advantage is that the drives can be arranged where high torques are necessary. This means either a direct disposition on the cylinder for which a high torque is necessary or in the vicinity of the cylinders for which high torques are necessary. This arrangement also makes it possible to avoid the transmission of high torques over many gearwheels with many transfer positions. An example would be a desirable central input of power to the impression cylinder. This advantage is enjoyed even if the printing press has only a single printing unit and is provided with only one drive of the type according to the invention. As a result, the transmission of the torques no longer needs to go through the entire gear train but can take place in all
Hartmann Klaus
Kruger Michael
Wagensommer Bernhard
Colilla Daniel J.
Greenberg Laurence A.
Heidelberger Druckmaschinen AG
Lerner Herbert L.
Stemer Werner H.
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