Knife cylinder for processing weblike material

A knife cylinder for processing weblike material has at least one slot in its cylindrical surface for receiving a web cutting/perforating knife retained in place by a plurality of pressure medium cylinders distributed over the length of the knife. A rigid wall within the slot limits the extent of the pressure cylinders, and push rods extending through the wall may be provided for transferring pressure from the pressure cylinders to the knife.

This invention relates to a cutting or knife cylinder for processing 
weblike material, such as paper, plastic sheets or metal foils, fabric or 
the like, having at least one slot formed in the cutting cylinder and 
lying parallel to the rotational axis of the cutting cylinder on its 
circumference and provided to receive and attach a knife arranged 
substantially parallel to the rotational axis of the cutting cylinder; 
pressure points are distributed over the length of each knife to clamp the 
respective knife with respect to the cutting cylinder by means of several 
pressure medium cylinders, pressing the respective knife against the 
cutting cylinder and distributed over the length of each knife, pressure 
conduit system is connected to the pressure medium cylinders and revolves 
with the cutting cylinder, for each knife at least one shim is arranged 
between that knife and associated pressure medium cylinder. The pressure 
medium cylinders assigned to each slot are arranged both within the slot 
and also substantially in the circumferential direction of the cutting 
cylinder, and the pressure medium cylinders are bellows cylinders made 
preferably of metal. 
Cutting cylinders of the aforementioned type are used in machines to 
produce cuts in weblike materials. These cuts can be produced with knives 
which do not have a continuous cutting edge so that in the manner a 
perforation is generated. However, the knives can also have a continuous 
cutting edge. Thus, it is possible to cut off sheets of specific length 
from a continuous web or to deposit this web into accordion-like folded 
stacks. The cutting or cut lines formed in the webs are usually aligned at 
right angles to the grain direction of the web to be processed. The knives 
required for this purpose are usually inserted into a revolving cutting or 
knife cylinder in such a manner that knives that have become dull can be 
exchanged without the entire cylinder having to be removed from the 
respective processing machine, for example a form printing machine. At 
least one knife is attached to each cutting cylinder. However, to form 
cross perforations, which are to exhibit a shorter distance between one 
another than corresponds to the diameter or circumference of the cutting 
cylinder, several knives, for example, two, three, six or eight knives are 
distributed regularly or irregularly on the circumference of the cutting 
cylinder. 
So that the knives can be effective in the desired manner, they must be 
adjusted relative to the web to be processed or to pressure cylinder 
interacting with the cutting cylinder. For this purpose, the knives are 
usually attached force-lockingly to the cutting cylinders or within the 
cutting cylinder. If the knives have become blunt in the course of their 
use, they have to be exchanged for new knives. However, an exchange of 
knives usually requires as a rule that both the cutter, in which the 
respective knife is installed, and another machine that eventually works 
together with the cutter, for example, a form printing machine, must be 
stopped. Stopping the machine automatically causes loss in production, 
which is as high as corresponds to the time in which the machines must be 
stopped. Therefore, one endeavors to perform the exchange of the knives, 
consuming as little time as possible. 
A device of the aforementioned type is known, for example, from U.S. Pat. 
No. 4,671,154, for which reason reference is made herein to this patent in 
order to support the description of the present patent application. The 
device described here can, however, be further simplified in its 
construction, from which it follows as the object of the present invention 
to improve the construction known from prior art in such a manner that its 
operation is even further simplified. 
SUMMARY OF THE INVENTION 
The aforementioned problem is solved by a device formed in the cutting 
cylinder to limit the extent of each of the pressure medium cylinders, 
this limiting device being arranged within the respective slot and between 
the respective pressure medium cylinders and the respective knife. The 
limiting device can be in the form of a strip-like bar such that the 
strip-like bar can be made integral with and the cutting cylinder. In 
addition, the strip-like bar can be provided with through holes, where the 
reciprocal distances of the holes correspond to the reciprocal distances 
of the respective pressure medium cylinders. Furthermore, push rods 
arranged between each pressure medium cylinder and the shim of the 
respective knife, such that each push rod can be guided by the strip-like 
bar. 
A bore, aligned at right angles to the base of the respective slot, can be 
formed in each of the shims under, and the inner diameter of the bore is 
greater than the outer diameter of a screw fastener extending through such 
bore. 
The pressure medium can be fed to each pressure medium cylinder through a 
conduit, which is formed in the cutting cylinder parallel to the 
respective slot. In so doing it must be taken into consideration that all 
components of the present device are tuned and dimensioned according to 
function. Owing to the present solution it is possible to initiate the 
forces induced by the pressure medium cylinders causing the clamping of 
the knives without the pressure medium cylinders expanding excessively. In 
addition, the result is a simpler assembly, since the push rods can be 
readily inserted into the lift limiter designed as the strip-like bar. In 
addition, the pressure medium cylinders can be easily located in the 
respective slot and connected there to a single screw in such a manner 
that a good seal is produced relative to the conduit system feeding the 
pressure medium due to the simple sealing surfaces. In addition, the shim 
assigned to each knife is not severely stressed in an undesired manner by 
the centrifugal force even if, for example, due to an operating error a 
knife or a substitute for a knife should be missing in the event for the 
case that at the point reserved for the knife the web is not to be 
perforated or cut. 
Other features and advantages follow from the following description of an 
of the invention. The individual features can be realized one by one 
individually or several features in any combination can be realized into 
embodiments of the invention. The invention will now be explained in 
detail with the aid of an embodiment that does not restrict the inventive 
idea and is shown schematically in the accompanying drawings. The 
embodiment can be modified in different ways within the scope defined by 
the basic idea. In this respect, nonessential machine parts that are 
adequately known to the expert are not shown in the drawings for the sake 
of greater clarity. But rather the drawings show only those parts that are 
necessary to explain the invention in detail and its advantages.

DETAILED DESCRIPTION OF THE INVENTION 
A web 1 of paper, plastic, metal, film, fabric or the like extends 
partially about a pressure cylinder 2. Simultaneously web 1 passes through 
a roller gap, which is formed by pressure cylinder 2 a cutting cylinder 3. 
Pressure cylinder 2 and cutting cylinder 3 can be rotated with the aid of 
a corresponding bearing 4 in a machine frame 5. At least one of the two 
cylinders 2 or 3 is driven, but it is also possible that both cylinders be 
connected together by gear wheels, gear belts or the like so that they can 
revolve in exact phase relation to each other. Thus it is only necessary 
to drive one of the two cylinders, since the other is also driven by the 
synchronizing device comprising gear wheels, gear belts or the like. 
Cutting cylinder 3 has knives or knife positions 6, 7, 8, 9, 10, and 11. 
The knives located at positions 6 to 11 extend substantially in the 
direction of the geometric axis of cutting cylinder 3 and are attached in 
the cutting cylinder 3 parallel to or slightly sloped relative to this 
axis. The related knives can have a continuous cutting edge or a cutting 
edge interrupted by transverse grooves. If the knives have a continuous 
cutting edge, web 1 is traversely cut into single sheets when the web 
flows through the roller gap formed by cylinders 2 and 3. 
If the knife cutting edges are interrupted by tranverse grooves, web 1 is 
not totally severed at right angles to its formation direction. Rather the 
result is a plurality of spaced cuts in web 1, connected by connecting 
ties. In this manner web 1 is perforated at right angles to its formation 
direction indicated by arrow 12. Due to this perforation it is possible to 
tear individual sheets from web 1 in one later operation. However, it is 
also possible, for example, that those points at which web 1 is weakened 
by perforations extending at right angles the web 1 can be folded at right 
angles to its formation direction during a later accordion folding 
operation. 
FIG. 1 shows one example of a cutting cylinder 3, on the circumference 
which six knives are distributed uniformly. In contrast, it is also 
possible to design the cutting cylinder 3 in such a manner that one, two, 
three, four, five, seven, eight or ten knives or however a different 
number of knives can also be attached uniformly distributed on the 
circumference of the cutting cylinder. Corresponding to the number and 
positions of provided knives, there are also a number of open slots 
serving to attach each of the knives to the cutting cylinder. In addition, 
however, it is also possible to form a specific number of slots into 
cutting cylinder 3, but in the respective production operation, on the 
other hand, to use less than all of these slots or the knives depending on 
the particular requirement of the production to be targeted and to insert 
ineffective, optionally socalled dummy knives at the nonused positions. 
Cutting cylinder 3 and pressure cylinder 2 are attached and can be rotated 
in such a manner in machine frame 5 that these machine parts form a 
subassembly, which can be removed as a whole from main frame 13 of the 
machine and can be exchanged for another similar subassembly. To this end, 
it is necessary to attach machine frame 5 in main frame 13 by means of 
clamping shoes 14 and 15, nuts 16 and 17 and tie rods 18 and 19, screwed 
into main frame 13, for the period of the machine time. In contrast, it 
is, however, also possible to omit machine frame 5 and related fasteners 
and to position cutting cylinder 3 and pressure cylinder 2 directly in the 
main frame 13 of the machine. 
It is apparent from FIG. 2 that slots 20, 21, 22, 23, 24, and 25 
representing, for example, six knife positions are formed in cutting 
cylinder 3. The first of these slots 20 is shown in detail, whereas the 
remaining identical slots 21-25 are indicated merely with a dash-dotted 
straight line in the interest of clarity. Each of the slots has a side 
wall 26, which represents within cylinder 3 a surface extending 
substantially radial to said cylinder. Extending parallel to each side 
wall 26, each slot has a second side wall 27, which is also formed in 
cutting cylinder 3. 
Base 28 of each slot with its portions 28a and 28b extends perpendicular to 
the first side wall 26 and to the second side wall 27. Each slot thus has 
three surfaces 26, 27, and 28. Each slot is open in the radial direction 
outwardly of cutting cylinder 3. Into each slot a shim 29 is inserted in 
such a manner that base 30 of shim 29 abuts portion 28a of the base of the 
slot. Each shim 29 has at least one bore 31, through which a screw 
fastener 32 is extended. Bore 31 of shim 29 has preferably a larger 
diameter than the outer diameter of screw 32. Screw 32 is screwed into a 
thread 33, which is formed in cutting cylinder 3 such that the geometric 
axis of screw 32 is perpendicular to the geometric axes of pressure medium 
cylinders 34, 35, 36 and 37, i.e., also relative to the base 28 of slot 
20. 
The pressure medium cylinders are preferably bellows cylinders made of 
metal. Knife 6 located in knife position 6 is pressed, for example, 
against side wall 26 of slot 20 with the aid of pressure medium cylinder 
34 with the insertion of shim 29 and a strong, rigid push rod 38. Push rod 
38 is guided in a through hole or perforation 39 formed in, a strip-like 
bar 40 attached in slot 20. This strip-like bar can be attached to cutting 
cylinder 3, for example, at the base of slot 20 and thus abut the base 28 
of slot 20. Preferably, however, bar 40 is made of the same component as 
cutting cylinder 3, i.e., it is machined out of the material of cutting 
cylinder 3. Since pressure medium from the channels 41, 42 and 43 is fed 
to pressure medium cylinder 34, a force is generated that moves the push 
rod 38 to the left in FIG. 4, thus moving shim 29 with respect to screw 32 
as far as the difference between the diameter of the bore 31 and the outer 
diameter of the screw 32 allows and pushes knife 6 against cutting 
cylinder 3 from the right in FIG. 4 and clamps with said cutting cylinder 
force-lockingly. In addition, since a pressure spring 44 is provided 
between the head of screw 32 and shim 29, a movement of shim 29 with 
respect to screw 32 is permitted. 
Conduits 42 and 43 are formed in worked into a screw 45, which is provided 
with a seal 46. Similarly pressure medium cylinder 34 is provided with a 
seal 47. When all dimensions are suitably chosen, bar 40 limits the 
expansion or extent of cylinder 34, a feature that has, however, no 
negative effect on the hold of knife 6, since between cylinder 34 and 
knife 6 is inserted push rod 38, which is somewhat longer than the width 
of bar 40 visible in FIG. 4 so that adequate freedom of movement remains 
for the pressure medium cylinder in order to clamp or release knife 6. 
Whatever force applies to pressure medium cylinder 34 also applies in an 
analogous manner to all pressure medium cylinders inserted into cutting 
cylinder 3, for example to the other pressure medium cylinders 35, 36 and 
37, which are distributed over the length of knife 6 and the length of all 
other knives. Pressure medium cylinders 34 and 35 maintain, for example, a 
distance 48 between each other; pressure medium cylinders 35 and 36, 
distance 49; and pressure medium cylinders 36 and 37, distance 50. The 
corresponding, related holes, as indicated, for example, by hole 39, 
maintain distances 51, 52, and 53 among each other in such a manner that 
each perforation is arranged concentrically to the respective pressure 
medium cylinder. The respective push rod such as push rod 38 lies in the 
same line of action. Thus, each push rod is guided by means of the 
strip-like bar 40, since each push rod is located in a corresponding 
recess of this bar and is enclosed by the bar with adequately large 
clearance for its movement. Thus bar 40 divides slot 20 into two subslots 
with bases 28a and 28b, where bar 40 penetrates preferably the total axial 
length of cylinder 3. Its surfaces shown in FIG. 4 as vertical edges 
extend parallel to the side walls 26 and 27 of slot 20. The same applies 
to all other slots provided for the accommodation of the knives and 
belonging to cutting cylinder 3. Conduit 41 is formed in cutting cylinder 
3 parallel to the respective slot. It intersects those bores through which 
screw 45 or other analogous screws extend so that the result is an 
integrated conduit system at least per slot or with the aid of suitable 
pipe lines. The respective conduit system is connected in turn to a 
pressure generator (not shown). 
Parts List 
1 web 
2 pressure cylinder 
3 cutting cylinder 
4 bearing 
5 machine frame 
6 knife (position) 
7 knife (position) 
8 knife (position) 
9 knife (position) 
10 knife (position) 
11 knife (position) 
12 arrow 
13 main frame 
14 clamping shoe 
15 clamping shoe 
16 nut 
17 nut 
18 tie rod 
19 tie rod 
20 slot 
21 slot 
22 slot 
23 slot 
24 slot 
25 slot 
26 side wall 
27 side wall 
28 base 
29 shim 
30 base 
31 bore 
32 screw 
33 thread 
34 pressure medium cylinder 
35 pressure medium cylinder 
36 pressure medium cylinder 
37 pressure medium cylinder 
38 push rod 
39 perforation 
40 bar 
41 channel 
42 channel 
43 channel 
44 pressure spring 
45 screw 
46 seal 
47 seal 
48 distance 
49 distance 
50 distance 
51 distance 
52 distance 
53 distance