Printing – Rolling contact machines – Rotary
Reexamination Certificate
1998-11-30
2001-06-05
Yan, Ren (Department: 2854)
Printing
Rolling contact machines
Rotary
C101S183000, C271S193000, C310S013000, C318S038000
Reexamination Certificate
active
06240843
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a sheet transport system, a propulsive drive device, a web infeed device and a transport gripper system for a rotary printing machine including a sheet transport device having a sheet holder, and a first and a second propulsive drive element for propulsively driving the sheet transport device guidingly in a first and a second guide rail, respectively, the second guide rail extending substantially parallel to the first guide rail, the first and the second propulsive drive elements forming rotors of an electric linear drive, the first and the second guide rails having a plurality of drive stations disposed thereon and forming a stator of the linear drive, and a control device assigned to the drive stations for controlling and regulating movement of the first and the second propulsive drive elements. Sheet transport systems for rotary printing presses have become known heretofore in the prior art and are installed or used, for example, in the feeder region of a printing press to remove a sheet from a sheet pile and to feed the sheet to a first printing unit. Furthermore, it has become known heretofore to use sheet transport systems for transporting sheets within the printing press from printing unit to printing unit or for transporting the sheets from the last printing unit to a delivery pile in a delivery region, the transport of the sheets in the different printing press sections being generally performed by variously constructed sheet transport systems. Thus, in the feeder region, mechanically driven, mainly rectilinearly displaced suction devices in the form of lifting and dragging suckers are used. Between the printing units, i.e., within the printing press, the sheet transport is then usually performed by sheet transfer cylinders or drums with gripper devices arranged thereon. In the delivery region, the sheets are finally transported by gripper bars, which are fixed to two revolving endless chains arranged parallel to one another.
Furthermore, the German Non-prosecuted Patent Application (DE-OS) 25 01 963 discloses the practice of transporting the sheets through the entire printing press with the aid of a sheet transport system in the form of a gripper carriage with a gripper bar arranged thereon. The gripper carriage is driven, in this regard, by first and second propulsive or forward drive elements, which are guided in appertaining endless guide rails running at both sides in the housing of the printing press, and form the rotor of an electric linear motor. Extending along the two guide rails are endless stator coils, which produce an electromagnetic traveling field for the propulsive drive of the gripper carriage. In this regard, provision may be made for the coils to be subdivided into a plurality of electrically independent subsections, which are assigned to the respective printing units, in order to be able to control the speed of the gripper carriage with high accuracy, for example, when it is passing a press nip. A disadvantage of the aforedescribed sheet transport system is that the stator coils are constructed as endless coils, which leads to a high electrical power demand and makes necessary a comparatively high control and regulation outlay and the corresponding costs associated therewith. Thus, particularly in order to achieve the in-register feeding of sheets into the press nips of the respective printing units, it is necessary to drive each individual winding of the endless coil by a separate control device, in order to attain the required accuracy.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a sheet transport system for rotary printing presses which may be installed universally in the individual subsections of a printing press, and has a movement which takes place with an accuracy required for the in-register sheet transport in a printing press and which requires, in addition to a reduced outlay or expense for devices for controlling and regulating the propulsive drive movement, a comparatively low electrical power demand.
With the foregoing and other objects in view, there is provided, in accordance with a first aspect of the invention, a sheet transport system for a rotary printing press, including a sheet transport device having a sheet holder, and a first and a second propulsive drive element for propulsively driving the sheet transport device guidingly in a first and a second guide rail, respectively, the second guide rail extending substantially parallel to the first guide rail, the first and the second propulsive drive elements forming rotors of an electric linear drive, the first and the second guide rails having a plurality of drive stations disposed thereon and forming a stator of the linear drive, and a control device assigned to the drive stations for controlling and regulating movement of the first and the second propulsive drive elements, each of the first and second propulsive drive elements comprising a structure formed of magnetizable material, at least part of which is movable relative to another part thereof, and the drive stations being spaced from one another, at least in some sections of the sheet transport device, a distance which is at most equal to the length of the propulsive drive elements.
In accordance with another feature of the invention, the structure of the propulsive drive elements, respectively, is a link chain formed of the magnetizable material and including at least two individual elements articulatedly connected to one another.
In accordance with a further feature of the invention, the structure of the propulsive drive elements, respectively, is a flexible belt formed of the magnetizable material.
In accordance with an added feature of the invention, the magnetizable material is formed by permanent magnets.
In accordance with an alternative feature of the invention, the magnetizable material contains permanent magnets.
In accordance with an additional feature of the invention, the magnetizable material is a ferromagnetic material.
In accordance with yet another feature of the invention, the flexible belt is formed at least partly with ferromagnetic material, and slots are provided in the belt.
In accordance with yet an added feature of the invention, the sheet transport system is in combination with a printing press, and the sheet transport device is arranged between an upline and a downline printing unit of the printing press, and the sheet holder is formed by gripper devices for accepting a sheet from gripper devices of the upline printing unit and transferring the sheet to gripper devices of the downline printing unit.
In accordance with yet a further feature of the invention, the sheet transport system includes a plurality of sheet transport devices simultaneously revolvable together within the guide rails.
In accordance with yet an additional feature of the invention, the sheet transport device is arranged in a delivery region of a printing press, and the sheet holder is formed by gripper devices for accepting a sheet from an upstream printing unit of the printing press and depositing the sheet on a pile.
In accordance with still another feature of the invention, the control device serves for controlling the movement of the propulsive drive elements of the sheet transport devices in the region of the sheet pile so that distances between two successive sheet transport devices are less than the length of a transported sheet, and so that an imbricated formation of the deposited sheets is formed.
In accordance with still a further feature of the invention, the sheet transport system includes at least one dryer disposed in vicinity of the guide rails, so that the printed sheets are guidable past the dryer.
In accordance with still an added feature of the invention, the first and second guide rails, in the region of the at least one dryer, are divided into two rail paths running above one another wherein the speed of the sheet transport devices is reduced, and a diverter is provided thereat for feeding succe
Kruger Michael
Laubscher Hans-Jorg
Greenberg Laurence A.
Heidelberger Druckmaschinen AG
Lerner Herbert L.
Stemer Werner H.
Yan Ren
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