Roll press, specifically for the paper industry

A roll press with two press rolls which together form a press gap and whose axes are situated in a press plane. A journal is disposed on the ends of each roll, with pillow blocks for receiving the journals, with a rack for supporting the pillow blocks, and with tie rods which are arranged on both sides of the press plane and at least approximately parallel to it. Cradles are provided which support the pillow blocks. Between the cradles and the pillow blocks is an articulated joint which enables the pillow blocks to pivot about an axis which extends perpendicularly to the press plane and essentially in the axial plane of the respective roll.

BACKGROUND OF THE INVENTION 
The invention concerns a roll press of the type having two press rolls 
forming with each other a press gap, and having axes situated in a press 
plane. A journal is disposed on the ends of each roll, with pillow blocks 
for receiving the journals and a rack for supporting the pillow blocks. 
Tie rods are arranged on both sides of the press plane, and are generally 
parallel to it. 
Roll presses are known in a plurality of embodiments. Only exemplary 
reference is made to DE 41 10 205 A1. Here, two press rolls are arranged 
in a way such that the press plane extends vertically and the press frame, 
consequently, is of an upright arrangement. There are varying arrangements 
known as well. 
U.S. Pat. No. 4,837,907 describes a roll press with two rolls where the 
pillow blocks of the one roll are by means of screws fastened to the 
pillow blocks of the other roll. In the load state, the screws must 
transfer high tension forces, corresponding to the compression force 
prevailing in the press gap. 
On the categorial roll press, the pillow blocks of the one press roll and 
those of the other press roll are joined by tie rods which are bendable 
with relative ease; moreover, the pillow blocks of the one press roll are 
axially movable in relation to the pillow blocks of the other press roll. 
This embodiment has several advantages: to begin with, the tie rods are 
capable of transferring the necessary tension forces. Furthermore, this 
embodiment allows a quick release and restoration of the coupling between 
the pillow blocks of the one roll and those of the other. Lastly, this 
embodiment allows in the case of different length changes of the two rolls 
a relative movement between both, including their pillow blocks, without 
creating stresses. This embodiment of a press has proved to be very 
suitable, for which reason the invention is based on it. 
But it has been demonstrated that the said tie rods cannot always be 
fashioned as bendable as is necessary to avoid stresses. A forced bending 
of the tie rods can occur, specifically when the axial displacement 
between the two rolls becomes very large as the result of an extremely 
different axial expansion. Thus, the tie rods are stressed not only by 
design tension, but additionally also by an undesirable degree of bending. 
The problem underlying the invention is to fashion a roll press in such a 
way that the tie rods will be stressed extensively by tension. 
SUMMARY OF THE INVENTION 
This problem is solved by the inventive features of the present invention. 
In one form thereof, the invention comprises a roll press comprising two 
press rolls forming with each other a press gap, the respective axes of 
the press rolls being situated in a press plane. A journal is disposed at 
an end of each press roll. A respective pillow block receives each 
journal, and a rack supports the pillow blocks. A tie rod is arranged on 
each side of the press plane generally parallel to said press plane. A 
respective cradle is provided for supporting each pillow block, and an 
articulated joint is arranged between the cradles and the pillow blocks to 
enable the pillow blocks to pivot about an axis which extends 
perpendicular to the press plane and generally in the axial plane of the 
respective press roll.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The roll press illustrated in FIGS. 1, 1A and 1B has a lower, first press 
roll 1 and an upper, second press roll 3. The axes of these press rolls 
are situated in a press plane E. The first press roll has a rotatable 
shell 1a and, fastened to it, a journal 2 resting by means of an 
antifriction bearing 2a in a pillow block 5 (with caps 5a and 5b). The 
pillow block 5 sits on a frame-shaped machine rack 15, of which several 
components are indicated in FIG. 1. 
The upper, second press roll 3 is a so-called long-gap press roll. Its roll 
shell 3a is a tubular, flexible press shell mounted on two rotatable shell 
support disks 3b. Each of the shell support disks rests on the stationary 
journal 4 of a stationary support element 4a extending through the 
interior of the roll shell 3a. The support element 4a has opposite the 
lower press roll 1 a recess 4b and, in it, a piston type, hydraulically 
actuated press shoe 4c. The latter, with its concave sliding surface, 
forces the press shell 3a on the lower press roll 1, thereby forming an 
extended (in running direction) press gap, through which runs, together 
with at least one continuous felt F, a paper web to be dewatered. 
The upper press roll 3 (on each roll end) rests with the journal 4 in a 
pillow block, which hereafter will be called "support element 6." Provided 
between the pillow block 5 and support element 6 is an adapter 9 which is 
removable and rests on the pillow block 5. Bearing on said adapter is the 
support element 6 of the upper press roll 3 when the roll press is in its 
no-load state (i.e., with the recess 4b nonpressurized). Illustrated, 
however, is the load state in which the press shoe 4c exerts on the lower 
press roll 1 a compression force. The reaction forces resulting thereof 
are transferred, with the aid of pliant tie rods 7 and 8, from the support 
element 6 to the pillow block 5. 
According to FIG. 1, a pliant tie rod 7 each is provided on both sides of 
the press plane E. These tie rods are inserted from the side into recesses 
of the pillow block 5 and support element 6. Each of the pliant tie rods 
7, 8 has on each end a hammer head 20 and is preferably fashioned after a 
leaf spring, the "leaf plane" of which extends perpendicularly to the 
press plane E. This allows the tie rods 7, 8 to deform according to FIG. 
4, provided the support element 4, 4a of the second press roll 3 undergoes 
a length change (for instance thermally induced) and/or flexes under the 
compression force. Consequently, the support element 6 may be rigidly 
connected with the journal 4; the previously required axial sliding 
surface between these two components and a spherical sleeve are 
dispensable. 
The easy axial movability and/or tiltability of the support element 6 (as a 
length change or flexure of the support element 4, 4a occurs) is aided yet 
by the measure described hereafter: The length of the flexible tie rods 7, 
8 is so chosen that the support element 6, in the load state of the roll 
press, lifts off the adapter 9 somewhat. In other words: a play p is 
created between the support element 6 and the pillow block 5. The 
magnitude of this play can be determined by inserting on each of the tie 
rods 7, 8, between the hammer head 20 and support element 6, a U-shaped 
wedge 10, 11 more or less deep. With this wedge it is possible, in the 
no-load state of the roll press, to eliminate the play p or slightly 
prestress the tie rods 7, 8. 
The embodiment according to FIGS. 2 and 3 again shows a roll journal 2, 
which is installed in a ball bushing, or sleeve, 30 which, in turn, is 
fitted in the pillow block 5. Here, an especially low-friction slide 
pairing has been effected, and at that, a ground ball in a housing coating 
containing PFTE. This creates a smooth tiltability. 
The pillow block 5 is pivotably mounted in a cradle 31. The mounting is 
effected by means of bores 32 in the cradle and pins 33 engaging the bores 
32. Provided between the cradles 31 and the pillow blocks 5 is an 
articulated joint which allows the pillow blocks 5 to pivot about an axis 
34 which extends perpendicularly to the press plane E and essentially in 
the axial plane of the respective roll 1,3. The tilt axis 34 can be seen 
from FIGS. 3 and 4. The cradle 31 features T-slots 35 for engagement by 
tie rods 7, 8 not illustrated here, so as to establish a tension 
connection to the respective cradle of the roll situated above. 
The embodiment according to FIGS. 4 and 5 is very similar to that relative 
to FIGS. 2 and 3. Provided here, however, on the one end of the roll, is a 
sliding block 36 which is able to slide in axial direction in a gate type 
guide 37. The coordination of the sliding block 36 with the pillow block 5 
is brought about by installing it on the respective bearing pin 33. The 
gate type guide 37, on the other hand, is coordinated with the cradle 31. 
The arrangement with the sliding blocks and gate type guide serves to 
absorb length changes between the press frame and roll axis. Such length 
changes are contingent, e.g., on temperature. The length compensation, 
naturally, may be provided on only a single roll end, where the movable 
bearing is contained. 
While this invention has been described as having a preferred design, the 
present invention can be further modified within the spirit and scope of 
this disclosure. This application is therefore intended to cover any 
variations, uses, or adaptations of the invention using its general 
principles. Further, this application is intended to cover such departures 
from the present disclosure as come within known or customary practice in 
the art to which this invention pertains and which fall within the limits 
of the appended claims.