Rotary press comprising an endless block belt

A rotary press comprises one or more impression cylinders (1) and a plurality of printing units, each of which comprises an inking unit (I) and an endless block belt (4). The block belt (4) is trained around a plurality of cylinders (5, 6, 7, 8), one of which (7) is movable into engagement with an associated impression cylinder (1). In the rotary press, the block belt of each printing unit is trained around four cylinders, which are disposed at the corners of a square or parallelogram. Two diametrically opposite ones (7, 8) of the cylinders are movable into engagement with the inking unit (I) and a picture-carrying web or an associated impression cylinder, and the two other diametrically opposite cylinders (5, 6) are tensioning cylinders, which are movably mounted in tracks (31) and, by a drive device (39), are movable toward and away from each other.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a rotary press comprising one or more impression 
cylinders and a plurality of printing units, each of which comprises an 
inking unit and an endless block belt, which is trained around a plurality 
of cylinders, one of which is movable into engagement with an associated 
impression cylinder. 
2. Description of the Prior Art 
In a rotary press of this kind, which is known from German Patent 
Specification 448,987, the endless block belt is trained around a main 
cylinder, which is movable into engagement with an impression cylinder. 
The belt is also trained around a guide cylinder, which is adjustable so 
that the format can be changed by the use of longer or shorter block 
belts. 
In a rotary press comprising a plurality of printing units, the distance 
from the inking cylinder to the impression cylinder, which distance is 
measured on the block belt, should always be the same so that an unclean 
print caused by different drying of the several inks used will be avoided. 
SUMMARY OF THE INVENTION 
For this reason it is an object of the invention to provide a rotary press 
of the kind described above and in which the distances between each inking 
cylinder and the associated impression cylinder, which distances are 
measured on the block belts, will always be the same. 
This object is accomplished in accordance with the invention in that the 
block belt of each printing unit is trained around four cylinders, which, 
in a side elevation view, are disposed at the corners of a square or 
parallelogram. Two diametrically opposite ones of the cylinders are 
movable into engagement with the inking unit and a picture-carrying web or 
with an associated impression cylinder. The two other diametrically 
opposite cylinders are tensioning cylinders, which are movably mounted in 
tracks and, by drive means, are movable toward each other and away from 
each other. In the rotary press in accordance with the invention it is 
ensured that the length of the block belt portion extending between the 
cylinder that engages the inking cylinder and the cylinder that engages 
the impression cylinder will always be the same so that all inks applied 
will be dried to the same degree. 
In the press in accordance with the invention, the printing cylinders and 
the tensioning cylinders around which the block belts are trained may be 
relatively small in diameter. 
The center lines of the bearings of the cylinders suitably define in side 
elevation a parallelogram having sides which are equal or different in 
length. 
In accordance with a further feature of the invention, the cylinders are 
rotatably mounted in laterally disposed mounting plates, which are rigidly 
interconnected and are non-rotatably connected to and laterally 
displaceable relative to the frame or carriage which carries the printing 
unit. For a sample adjustment of the lateral register, means may be 
provided for laterally adjusting the mounting plates. 
In accordance with a further feature of the invention a gear is 
non-rotatably connected to and axially displaceably mounted on a stub 
shaft of one of the cylinders and meshes with helical teeth of a central 
gear for driving the impression cylinder or cylinders. A bushing is 
non-rotatably connected to and axially displaceably mounted on a pin, 
which is fixed to the machine frame. The bushing is connected to a finger 
or to a disk, which extends into an annular groove formed in the hub of 
the gear, and adjusting means are provided for axially displacing the 
bushing. The longitudinal register can be adjusted by adjusting means 
which are used to axially adjust the bushing because a forward or rearward 
displacement will be imparted to the cylinder when the gear for driving 
the cylinder is displaced on the stub shaft. 
In a desirable arrangement, a format gear is rotatably mounted on and 
axially fixed to the bushing and meshes with the central gear and with the 
gear for driving the inking cylinder. The hub of the format gear carries 
the disk which extends into the annular groove of the hub of the 
cylinder-driving gear.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Illustrative embodiments of the invention will now be described more in 
detail with reference to the drawings. 
FIG. 1 shows a printing press comprising an impression cylinder 1, which is 
rotatably mounted in a machine frame 2, and six printing units 3 
associated with the impression cylinder. 
In this embodiment, the impression cylinder 1 cooperates with all six 
printing units 3. 
FIG. 2 shows a machine frame 2', which carries six printing units 3', each 
of which has a separate impression cylinder 1' associated with it. 
In each printing unit 3 or 3', the images to be printed are provided on a 
block belt 4, which is trained around four cylinders, namely, an upper 
tensioning cylinder 5, a lower tensioning cylinder 6, and two printing 
cylinders 7 and 8. The images to be printed may be transferred, for 
example, to material, such as paper or cloth, which is carried by 
impression cylinder 1. Both printing units 3 and 3' include a known inking 
unit, generally designated I, and include an inking cylinder IC to which 
ink is supplied in a known manner. Ink is thus transferred from inking 
cylinder IC to block belt 4 and from the block belt to the material 
carried by cylinder 1. 
As is particularly apparent from FIG. 4, all of the cylinders 5 to 8 are 
rotatably mounted in the printing press by axles which extend between two 
spaced apart, parallel side plates 9 and 10, which are rigidly 
interconnected by four round cross-bars 11. By means of pins 12 and 13 
connected to plates 9 and 10, respectively, the two plates 9 and 10 are 
non-rotatably but laterally displaceably mounted in side walls 15, 16 of 
the format cylinder carriage 17. A bushing 18 is fixedly mounted on the 
pin 12 at its outer end, which protrudes from the wall 15 of the format 
cylinder carriage 17. A motor-operated mechanism, the motor of which is 
not shown, serves to adjust the lateral register and comprises an 
adjusting member 19 that extends into a groove formed about the 
circumference of the bushing 18. The pin 13 comprises an end portion 14, 
which protrudes from the left-hand wall 16 of the format cylinder carriage 
17. A bushing 20 is non-rotatably connected to but axially displaceably 
mounted on the protruding end portion of the pin 13. The bushing 20 is 
axially adjustable relative to end portion 14 by an adjusting member 21 of 
a motor-operated mechanism, not shown, for adjusting the longitudinal 
register. The format gear 23 is mounted for rotation on the bushing 20 by 
means of a bearing 22 and meshes with the central gear 24, which is fixed 
to the impression cylinder 1 and has a diameter that corresponds to the 
diameter of the impression cylinder 1. The central gear 24 has helical 
teeth. The central gear 24 meshes also with another gear, i.e., stub shaft 
gear 25, which carries an extension 26 formed with an annular groove about 
its circumference. The annular groove receives a disk 27, which is secured 
to or integrally formed with the format gear 23. The adjusting member 21 
serves to adjust the longitudinal register in that it axially adjusts, via 
the bushing 20 and the format gear 23, the gear 25, which is non-rotatably 
connected to and axially displaceably mounted on the stub shaft 28 of the 
printing cylinder 7. Upon an axial displacement of the gear 25, the latter 
will impart a rotation to the printing cylinder because the gear 25 meshes 
with the helical teeth of the central gear 24. 
Dots 70, shown in FIG. 4 on the block belt 4 near its side edges, indicate 
teeth provided on the rear side of the belt. Such teeth may be used to 
cooperate with corresponding recesses in the cylinders 5-8 for positive 
engagement between the belt and cylinders. 
To permit an adjustment of the two tensioning cylinders 5 and 6 relative to 
each other, their stub shafts 29 are rotatably mounted in slides 30, which 
are guided in apertures 31 of the plates 9 and 10. Each of the two 
mutually opposite slides 30 mounted in apertures 31 of the respective 
plates 9 and 10 carries an adjusting nut 32 in engagement with screws 33 
and 34, respectively (see FIG. 3), which have mutually oppositely handed 
screw threads. The adjacent ends of the screws 33 and 34 are coupled by 
sleeves 35 to a shaft 36. Shaft 36 is rotatably mounted in a bearing 
bracket 37, which is integrally formed with or otherwise rigidly 
connected, e.g., by welding, to the plates 9 and 10. An angle member 38 is 
connected by screws to the bearing bracket 37 and carries a motor 39, 
which on its output shaft carries a pinion 40 meshing with a gear 41, 
which is secured to the shaft 36 (FIG. 5). By operation of the motor 39, 
the tensioning cylinders 5 and 6 can be displaced relative to each other, 
i.e., either toward or away from each other, to the same extent. This is 
necessary to tension the block belt and to permit the use of block belts 
differing in length. 
The invention should not be considered to be limited to the specific 
embodiments described; rather, the scope of the invention is defined by 
the claims which follow.