Printing – Rolling contact machines – Rotary
Reexamination Certificate
2001-06-22
2004-03-16
Colilla, Daniel J. (Department: 2854)
Printing
Rolling contact machines
Rotary
C101S225000, C101S227000, C101S232000
Reexamination Certificate
active
06705220
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to printing presses and more particularly to a device and a method for guiding a travelling web.
In a web-fed printing press, e.g. an offset lithographic printing press, one or more material webs, e.g. paper webs, are printed by respective print couples of printing units with different colors and are then fed to a folding apparatus for creating folded signatures. A folding apparatus typically comprises a superstructure in which a plurality of angle bars or turning bars are located and guide the paper webs from the printing units to the former boards of the folding apparatus. The angle bars can be air loaded with compressed air, which exits the angle bars through air nozzles, located in the surface of the angle bars and can also be coated with a chromium surface. Both the pressurized air and the coated surface reduce the friction of the angle bar surface and therefore marking of the freshly printed paper webs. For better access, the angle bars can be cantilevered in the superstructure of the folding apparatus.
The angle bars are used for offsetting and turning a guided travelling web or longitudinally cut ribbons of the web. A delivered portion of the web can be laterally offset with respect to an arriving portion of the web by the use of two parallel angle bars. The web can therefore be shifted for example from one side of the machine to the other side of the machine. The delivered portion of the web can also be turned with respect to the arriving portion of the web by the use of two parallel angle bars and an additional deflection roller, which is located between the two angle bars in direction of the web path.
The afore-mentioned angle bar arrangements are also used for bringing together and superposing printed paper webs before the webs are fed to a common former board of the folding apparatus.
U.S. Pat. No. 5,108,022 discloses a universal web turning system, particularly for printed webs derived from a rotary web-type printing machine. The turning system comprises a first and a second turning bar and a first and a second deflection roller which are retained in an essentially rectangular frame, with the position of the turning bars adjustable along the sides of the frame and the position of the deflection rollers being longitudinally adjustable along the sides of the frame as well as height-adjustable perpendicular to the plane of the web travelling between the respective turning bars and deflection rollers. The turning system allows for turning, offsetting or turning and offsetting a web of material especially a printed web.
For adjusting the print-to-cut register known devices are provided with an additional movable compensator roller, which by its movement changes the length of the paper path, and therefore also the print-to-cut register. U.S. Pat. No. 5,108,022 does not disclose how to adjust the print-to-cut register.
The device of the '022 U.S. patent has a disadvantage in that at least three guiding elements, the two turning bars and at least one additional deflection roller, are needed to provide the turning system with the necessary guiding characteristics.
BRIEF SUMMARY OF THE INVENTION
An object of the present invention is to provide for a reliable and efficient device for guiding a travelling web, which comprises few movable components for achieving the necessary guiding characteristics.
The present invention provides a device for guiding a travelling web comprising:
a first movable angle bar and a second movable angle bar;
the first movable angle bar being located in a position P
1
and the second movable angle bar being located in a position P
2
in a first operative mode to guide the travelling web from an entering direction D
1
to an exiting direction D
2
and to define a first print-to-cut registration setting;
the first movable angle bar being located in a position P
3
and the second movable angle bar being located in a position P
4
in a second operative mode to guide the travelling web from the entering direction D
1
to an exiting direction D
3
, the exiting direction D
3
being offset with respect to the exiting direction D
2
, the second operative mode having the first print-to-cut registration setting; and
the first movable angle bar being located in a position P
5
and the second movable angle bar being located in a position P
6
in a third operative mode to guide the travelling web from the entering direction D
1
to the exiting direction D
2
, the third operative mode having a second print-to-cut registration setting.
The terms P
1
to P
13
and D
1
to D
4
in this application are used herein solely to distinguish the positions and direction from one another, and are not meant to have any specific meaning. The operative modes may also be called operative conditions.
The present invention permits guiding of a travelling web, particularly shifting the exiting direction of the travelling web and permits adjusting the print-to-cut registration setting with only two movable angle bars. It is an advantage of the present invention that the number of movable components is reduced to only two movable angle bars without the need of further compensator rollers and that therefore a cost and maintenance reduction can be achieved.
It is possible to change, i.e. to move or locate the respective angle bars, from the first operative mode to the second or the third operative mode or to change from the second operative mode to the third operative mode. Also returning to the first operative mode is possible from the second or the third operative mode is possible.
In a further embodiment of the invention the device comprises at least one first movable device being operative for moving the first movable angle bar and at least one second movable device being operative for moving the second movable angle bar.
Preferably, at least one of the first and second movable angle bars is pivotable.
In a preferred embodiment of the invention at least one of the first and second movable devices is a sliding carriage and at least one of the first and second movable angle bars is pivotably mounted on the respective movable device. The sliding carriage provides a linear movement, preferably substantially perpendicular to the direction of the arriving portion of the travelling web, and by mounting the angle bars pivotally on the respective sliding carriages also a rotational movement can be provided and can be superposed with the linear movement of the sliding carriage.
It is further possible and in certain cases even advantageous to support at least one of the first and second movable angle bars by means of pistons, which are slidably supported by the sliding carriage, i.e. for example by a base body of the sliding carriage.
It is also possible that at least one of the first and second movable angle bars is pivotably mounted with both ends to one of the respective movable devices.
In accordance with another feature of the invention, the device further comprises at least one further guiding element, e.g. a third bar or a first deflection roller, located between the first angle bar and the second angle bar on the path of the travelling web, the further guiding element guiding the web from the first angle bar to the second angle bar thereby turning the web. The axis of the further guiding element, e.g. of the third bar can be located substantially parallel to the direction of the arriving portion of the guided web. Further, it is possible that the further guiding element of the device is movable.
A device according to the invention can also comprise two further guiding elements, e.g. a third and a fourth bar located between the first angle bar and the second angle bar on the path of a travelling web, the third and the fourth bar located one above the other, in order to guide the travelling web from a lower angle bar unit to an upper angle bar unit. This advantageously allows for feeding multiple-color pages to any part of a newspaper in a press with limited color capability.
All the movements of the angle bars,
Colilla Daniel J.
Culler Jill E
Davidson Davidson & Kappel LLC
Heidelberger Druckmaschinen AG
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