Cylinder unit for a web-fed printing press having cylinders movable during running production

A cylinder unit is provided for a web-fed printing press. The unit includes first and second cylinders which form printing gaps with a common first counterpressure cylinder. Third and fourth cylinders are provided which form printing gaps with a common second counterpressure cylinder. The four cylinders and the two counterpressure cylinders are cylinders of a single H-shaped cylinder bridge. The second and third cylinders are spaced from one another at such a distance that a web can run in between these two cylinders in their printing-on positions at the respective counterpressure cylinders and can run out after wrapping around the two counterpressure cylinders. The first and fourth cylinders are spaced so close to one another that they can be reversed from a printing-on position against their respective counterpressure cylinder into printing-on position in relation to one another.

FIELD AND BACKGROUND OF THE INVENTION 
The present invention pertains to a cylinder unit for a web-fed printing 
press. 
SUMMARY AND OBJECTS OF THE INVENTION 
The primary object of the present invention is to increase the flexibility 
of a cylinder unit with respect to the formation of printing gaps for a 
web to be printed on. 
According to the invention, a cylinder unit is provided for a web-fed 
printing press. The unit includes first and second cylinders which form 
printing gaps with a common first counterpressure cylinder. Third and 
fourth cylinders are provided which form printing gaps with a common 
second counterpressure cylinder. The four cylinders and the two 
counterpressure cylinders are cylinders of a single H-shaped cylinder 
bridge. The second and third cylinders are spaced from one another at such 
a distance that a web can run in between these two cylinders in their 
printing-on positions at the respective counterpressure cylinders and can 
run out after wrapping around the two counterpressure cylinders. The first 
and fourth cylinders are spaced so close to one another that they can be 
reversed from a printing-on position against their respective 
counterpressure cylinder into printing-on position in relation to one 
another. 
The present invention is based on a cylinder unit whose cylinders form an 
H-shaped cylinder bridge with four cylinders transferring printing ink 
onto a web and two central counterpressure cylinders for these four ink 
transfer cylinders. Two each of the four ink transfer cylinders of the 
H-shaped cylinder bridge are pivotable into a printing-on position to a 
common counterpressure cylinder. 
According to the present invention, two of the four ink transfer cylinders 
can be reversed from a printing-on position to their corresponding central 
counterpressure cylinder into a printing-on position to one another. The 
other two ink transfer cylinders are located at spaced locations from one 
another to the extent that a web to be printed on can run in between them 
unhindered and can run out after wrapping around both counterpressure 
cylinders. Due to this asymmetric arrangement of the four ink transfer 
cylinders to the two central counterpressure cylinders of the H-shaped 
bridge, a maximum flexibility is achieved with respect to the formation of 
print positions. 
The various features of novelty which characterize the invention are 
pointed out with particularity in the claims annexed to and forming a part 
of this disclosure. For a better understanding of the invention, its 
operating advantages and specific objects attained by its uses, reference 
is made to the accompanying drawings and descriptive matter in which a 
preferred embodiment of the invention is illustrated.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to the drawings in particular, FIG. 1 shows an H-shaped cylinder 
unit of a web-fed printing press. The cylinder unit has four cylinders 1, 
2, 3 and 4, which transfer printing ink onto a web B.sub.1 and/or B.sub.2. 
These four ink transfer cylinders 1 through 4 form a printing gap each, 
and a total of four printing gaps is formed with the two central 
counterpressure cylinders 5 and 6. The four ink transfer cylinders 1 
through 4 in the exemplary embodiment are rubber blanket cylinders, while 
the central counterpressure cylinders 5 and 6 are designed as steel 
cylinders. One plate cylinder 8 each is associated in the known manner 
with each of the four ink transfer cylinders 1 through 4. The cylinder 
unit shown is called, in general, a 10-cylinder unit. 
The arrangement of the ink transfer cylinders 1 through 4 as well as their 
plate cylinders 8 is symmetrical to an imaginary central vertical to the 
line connecting the axes of rotation of the two central counterpressure 
cylinders 5 and 6. However, the arrangement of the ink transfer cylinders 
1 through 4 is not symmetrical to this line connecting the axes of 
rotation of the two counterpressure cylinders 5 and 6. The two ink 
transfer cylinders 2 and 3, which are arranged on one side of this 
connection line, are located at a greater distance from one another than 
are the two ink transfer cylinders 1 and 4 arranged on the other side of 
this connection line. 
The clearance between the two ink transfer cylinders 2 and 3 is so great 
that a web B.sub.1 can be led through the space between these two 
cylinders, can be printed on in a first printing gap between the ink 
transfer cylinder 2 and the counterpressure cylinder 5, can be passed on, 
wrapping around the counterpressure cylinder 5 and the counterpressure 
cylinder 6 one after another, can be printed on again in another printing 
gap, which is formed by the ink transfer cylinder 3 and its 
counterpressure cylinder 6, and can run out unhindered between the ink 
transfer cylinders 2 and 3, in parallel to the intake of the web in this 
exemplary embodiment. This is shown in FIG. 1. Two deflecting rollers 11 
and 12, around which the web B.sub.1 is deflected before and after 
wrapping around the two counterpressure cylinders 5 and 6, are arranged in 
the intermediate space between the two ink transfer cylinders 2 and 3 to 
define a web run region with a feed in region and out feed region. 
The ink transfer cylinders 1 and 4, which are the upper ink transfer 
cylinders in the exemplary embodiment, are also in a printing-on position 
each against their respective counterpressure cylinders 5 and 6. The web 
B.sub.1 is printed on four times on one side in the cylinder position 
shown. The advantage of the cylinder arrangement according to the present 
invention in this position of the ink transfer cylinders 1 through 4 is 
that the web B.sub.1 does not wrap around any of the four printing 
cylinders 1 through 4. The web B.sub.1 wraps around the two 
counterpressure cylinders 5 and 6 and runs tangentially to each of the 
four ink transfer cylinders 1 through 4. Each of these four ink transfer 
cylinders 1 through 4 can therefore be taken out from the production even 
with the web B.sub.1 running, i.e., during a production, a 4.0 production 
in the exemplary embodiment, by pivoting it off from its corresponding 
counterpressure cylinder 5 or 6. This also applies to a pivoting on in the 
opposite case. 
While the ink transfer cylinders 2 and 3 that are the lower ink transfer 
cylinders in the exemplary embodiment are removed from the production by 
pivoting off, the two ink transfer cylinders 1 and 4 that are the upper 
ink transfer cylinders in the exemplary embodiment are spaced so close to 
one another that they can be reversed from their printing-on position 
against their corresponding counterpressure cylinder 5 or 6 into a 
printing-on position in relation to one another by pivoting off from the 
counterpressure cylinders 5 and 6 and by pivoting toward one another this 
alternative printing-on position of the two ink transfer cylinders 1 and 4 
is shown in FIG 2. The two ink transfer cylinders 1 and 4 are each 
printing on opposite sides of another web in this alternative printing-on 
position. For example, a second web B.sub.2 can be printed on, e.g., in 
one color on both sides by the two ink transfer cylinders 1 and 4 in the 
position as shown in FIG. 2. This position provides a first 
cylinder/fourth cylinder printing gap. Thus, a two-web production is shown 
in FIG. 2. The web B.sub.1 is printed on here by the two ink transfer 
cylinders 2 and 3 one after another on one side in two colors, while the 
web B.sub.2, deflected by deflecting cylinder 10 corresponding to the 
intended print production, is printed on by the two ink transfer cylinders 
1 and 4 on both sides, in one color. 
Not only is the arrangement according to the present invention especially 
flexible in terms of the feasible alternative production possibilities, 
but it is also especially compact. Compared with an H-shaped bridge with 
two central counterpressure cylinders, which is symmetrical with respect 
to both the line connecting the axes of rotation of the two 
counterpressure cylinders 5 and 6 and the central vertical to this 
connection line, overall height is saved by the nonsymmetrical arrangement 
according to the present invention due to the flat upper V bridge of the 
two ink transfer cylinders 1 and 4 as well as their plate cylinders 8. 
Because of the narrower distance between the two upper ink transfer 
cylinders, the upper V bridge is flatter at equal overall height than the 
lower N bridge of the 10-cylinder unit. At the same time, the advantages 
of the wrap-free guiding of the web (wrap-free also with respect to the 
two more closely spaced ink transfer cylinders) are obtained, because the 
pivoting on and off of ink transfer cylinders during running production is 
simplified due to the wrap-free guiding of the web, since the pivoting on 
and off of cylinders does not lead to vibrations of the web, which would 
not be tolerable with respect to the quality of the production. In 
particular, the path of the web is not changed by the pivoting on and off, 
i.e., by the reforming of printing gaps and print positions. 
A preferred drive concept is also shown in the figure. There is no positive 
drive connection between the ink transfer cylinders 1 through 4 and the 
counterpressure cylinders 5 and 6 among each other. The cylinders 1 
through 6 are at best in a frictional connection via the web and via 
bearer rings. Each of the cylinders 1 through 6 is driven by a separate 
motor 7. The force is transmitted from each of the motors 7 via a 
transmission 9, preferably a toothed belt, directly to the cylinders 1 
through 6. The downstream plate cylinders 8 are positively connected with 
their corresponding ink transfer cylinders 1 through 4 to the drive, which 
is thus a common drive. As an alternative, it would be possible for the 
motors 7 to drive, instead of the ink transfer cylinders 1 through 4, the 
plate cylinders 8 associated with them likewise directly via a 
transmission, preferably likewise a toothed belt, and the ink transfer 
cylinders 1 through 4 would also be driven in this case in tow of their 
respective plate cylinder 8. It would also be possible to positively 
connect the two counterpressure cylinders 5 and 6 on the drive side with 
one of the ink transfer cylinders to the drive, which would thus be a 
common drive. However, the configuration shown in the figure with the 
separately driven counterpressure cylinders 5 and 6 is preferred because 
of the facilitated pivoting on and off of the ink transfer cylinders. 
While a specific embodiment of the invention has been shown and described 
in detail to illustrate the application of the principles of the 
invention, it will be understood that the invention may be embodied 
otherwise without departing from such principles.