Cutting width modifying means for a longitudinal web cutting machine

Cutting width modifying means for a machine for cutting a web of material and having groups of cutting elements of the bottom blade kind for longitudinal cutting of the web wherein the cutting elements are provided as sleeves mounted on a shaft, releasably secured against rotation thereon by keys and axially adjustable by means of externally screw threaded rings mounted in screw threaded portions of the bores of the sleeves and non-rotatably secured on the shaft, retaining means being provided selectively to retain one or more of the sleeves against rotation so that it or they is or are axially adjusted on the shaft upon rotation of the shaft by a servo motor.

The invention relates to cutting width modifying means for a machine for 
cutting a web of material and having groups of cutting elements of the 
bottom blade kind, for longitudinal cutting of the web, the groups of 
cutting elements being arranged one beside the other on a cutting element 
group carrier. 
Cutting width modifying means for machines for cutting a web of material 
have previously been proposed, in particular for cutting machines which 
are provided with so-called top blades and bottom blades. These blades are 
usually in the form of circular blades, and the webs of material are 
divided up by means of a shearing cut in such a way that a single wide web 
of material is fed to the machine and at least two correspondingly 
narrower webs of material leave the cutting machine after the cutting 
operation. In this cutting machine, the cutting operation is performed by 
means of a per se known co-operation of top and bottom blades. 
In addition to other differences, the previously proposed web roll cutting 
machines may also be distinguished by reference to the different kinds of 
web guide action. In the first group of such cutting machines, the web of 
material to be cut is moved past the bottom blades either tangentially or 
at most extends around the bottom blades over only a few degrees of angle 
of the periphery thereof, whereby the web of material is cut. 
In the second major group however the web of material to be cut is caused 
to extend around the cutting bottom blade, and the degree of looping of 
the web of material around the bottom blade may be up to 270.degree.. 
In previously proposed cutting machines of the first group, where the web 
extends substantially tangentially to the blade, when a change in the 
width at which the web is cut is desired, the adjustment of the bottom 
blades which is necessary is relatively easy. Indeed, the bottom blades 
are usually arranged on a bottom blade shaft which carries them without 
any intermediate members, that is to say, the spacings between the 
individual bottom blades are not filled with spacer members so that when 
adjustment is required the blades may be easily displaced, without there 
being any necessity for the blades and sleeves to be dismantled and 
re-installed again at fresh spacings. 
In contrast to this, when a change in the width of cut is desired in a 
cutting machine of the second group, which operates on the principle of 
the web being looped around the blades, account must be taken of the fact 
that spacer members or sleeves are disposed between the individual bottom 
blades. These spacer members or sleeves are of the same diameter as the 
bottom blades, because the web of material which is to be cut and which is 
looped around the bottom blades must be protected from damage by being 
supported between the cutting positions. The webs in question may be in 
the form of very thin and thus easily deformable webs in the form of films 
and other sheet materials which are correspondingly easy to damage. 
Therefore, when a change in the width of cut is desired, in the bottom 
blade adjustment operation which is necessary for this purpose, it is 
necessary to adjust not only the distances of the bottom blades from each 
other, but also the spacer sleeves between the bottom blades. As obviously 
the spacer sleeves cannot be expanded or contracted as desired, the 
different distances between the bottom blades must be precisely filled 
with different spacer sleeves from those previously used, that is to say, 
spacer sleeves which are of greater or narrower width, so that the very 
thin webs of material which are to be cut by passing around the bottom 
blades can be handled without suffering damage. In practice therefore, 
whenever the cutting width is to be adjusted, all the bottom blades and 
all the spacer sleeves must be removed from the bottom blade shaft which 
carries them and must then be refitted at the fresh distances apart or 
with new spacer sleeves of the fresh width required. 
For the purposes of reducing the considerable conversion times required in 
changing the apparatus in this manner, devices have already been 
developed, in which, instead of the bottom blades with spacer sleeves, 
grooved sleeves are used, or in which the bottom blade shaft is provided 
only with bottom blades or bottom blade discs and grooved discs. In this 
case, when a change in cutting width is to be effected, it is not 
necessary for the bottom blade shaft to be provided each time with fresh 
spacer sleeves, but instead each top blade is fitted into that one of the 
grooves which is at the desired or approximately desired spacing. With 
this arrangement of bottom blades, the minimum spacing of the grooves 
which is technically possible is from 3 to 5 mm. As however variations in 
regard to the widths of the webs cut of .+-.0.5 mm may be required, in the 
case of printed webs of material even closer smaller variations of less 
than 0.5 mm may be required, the above-mentioned improvement can only be 
used in a few cases in prior art machines. 
Improvement as regards the adjustment means has been proposed involving 
so-called `razor-blade cutting apparatus`, in the operation of 
`mirror-reflected cut` or `open web motion`. However, for reasons which 
are well known to the man skilled in the art, such cutting apparatus 
cannot be used for cutting many types of film, quite apart from the fact 
that the quality of the cut does not correspond to the above-mentioned 
shearing cut using circular blades. 
The present invention therefore has among its objects to solve the problems 
outlined above by providing cutting width modifying means for a machine 
for cutting a web of material and having groups of cutting elements of the 
bottom blade kind for longitudinal cutting of the web, wherein the groups 
of cutting elements are disposed one beside another on a cutting element 
group carrier, the cutting element group carrier and the cutting element 
groups are provided with co-operating disengageable coupling means in the 
form of keys and screw threads which permit selective relative rotation of 
the cutting element group carrier with respect to individual ones of the 
cutting element groups to adjust the axial position of cutting elements of 
one of the groups with respect to cutting elements of another of the 
groups and thereby permit variation in the spacing of the longitudinal 
cuts in the web. 
The above-mentioned disengageable coupling means thus provide easy and 
hitherto unexpectedly rapid adjustment of the positions of the cutting 
elements relative to each other, and also of the position of the cutting 
elements relative to the carriers of the cutting elements. It is 
advantageous for the cutting element group carrier to be formed as a shaft 
provided with at least one longitudinal groove and a further longitudinal 
groove. The groups of cutting elements preferably include bottom blade 
sleeves each having a bore in which the shaft is received and each having, 
in said bore, at least one longitudinal groove, a screw threaded portion 
with the screw threaded ring releasably but non-rotatably connected to the 
shaft by way of a projection on the ring engaged in said further 
longitudinal groove in the shaft, but at the same time the same screw 
threaded ring is releasably but axially non-displaceably connected to the 
shaft by spacer members and fitting members. A form fitting key is 
preferably disposed in said one longitudinal groove in the shaft, the 
fitting key having cams for releasable engagement in said at least one 
longitudinal groove in the bottom blade sleeves. The bottom blade sleeves 
are selectively securable against undesired rotary movement by retaining 
means. 
The retaining means preferably comprise a shell member, with a friction 
lining engageable with the respective bottom blade sleeve and mounted to 
be axially movable at least to the same extent as the axial movement of 
the respective bottom blade sleeve during axial adjustment thereof. 
A servo motor is preferably provided to rotate the bottom blade shaft 
through very small angles of rotary movement, of for example 3.degree. and 
less, or if desired through very large angles of rotary movement, to 
effect axial adjustment of the bottom blade sleeves, said servo motor 
being independent of a drive motor which rotates the bottom blade shaft 
during normal operation of the machine. 
The present invention can make it possible for the first time for the 
adjustment of cutting width on the bottom blade shaft to be effected 
reliably and indeed without the setting operators which were previously 
required, without the previous conversion times of up to 20 minutes, 
instead requiring conversion times of 30 seconds to about 2 minutes. In 
addition, the invention can make it possible for the first time for the 
operation of adjusting the cutting width on the bottom blade shaft, in 
machines in which the web of material is looped around the bottom blades, 
to be fully automated. In this way, in practice it is possible 
commercially to perform small orders for cutting web lengths of a weight 
of 100 to 500 kg, as the operations of cutting width adjustment which 
naturally become necessary at particularly frequent intervals on small 
orders, within a unit of time, can now be effected without high cost, in a 
manner which is economical both in respect of time and expense. 
Instead of using bottom blade sleeves made in one piece with grooves 
machined therein, it is equally possible to use bottom blade sleeves which 
are composed in per se known manner by the usual main basic body member, 
blade discs and grooved discs, and associated screw means. 
The relative rotary movement between the bottom blade shaft and the bottom 
blade sleeve can, if desired, be provided by driving the sleeve, instead 
of by driving the shaft. The number of longitudinal grooves in the bottom 
blade sleeves can be varied. If the form fitting key still provides for 
the required transmission of force, the form fitting key may be of a very 
small size, so that the number of longitudinal grooves per unit can be 
considerably increased. Conversely, it is possible for the number of 
longitudinal grooves to be reduced if desired, if the graduated spacing of 
the bottom blade sleeves relative to each other is not made fine but is to 
be `coarsened`. It is also within the scope of the invention for the 
longitudinal grooves to be replaced by an internal longitudinal spline or 
tooth assembly in the bottom blade sleeve and on the fitting key when 
there is a requirement for minimum adjustment of the spacing between the 
bottom blade sleeves relative to each other of for example less than 0.1 
mm. 
The form fitting key may comprise a commercially available fitting key with 
additionally inserted pin members. The preferred drive for the bottom 
blade shaft is a servo motor but it could equally be manual. The cutting 
width modifying means may also be made movable, within the setting of a 
corresponding cutting machine, and in addition may be installed or 
attached, not only in conjunction with a so-called roller winding machine 
but also, according to requirements and wishes, equally well on other 
commercially available machines, for example a bag manufacturing machine, 
a transverse cutter, a machine for further processing of film material, a 
printing machine, a lining machine or a coating machine.

Referring to the drawings, a cutting device in a winding and cutting 
machine includes a bottom blade shaft 1. As can be seen, particularly in 
FIGS. 1, 2A, 2B and 4, bottom blade sleeves 2a to 2g are disposed on the 
bottom blade shaft 1, the bottom blade sleeves 2 being at a variable 
spacing from or relative to each other. The bottom blade sleeves 2 have 
two possible degrees of freedom on the shaft 1, the first degree of 
freedom being rotation about the longitudinal axis of the shaft and the 
second degree of freedom being axial movement in the direction of the 
longitudinal axis of the shaft. These degrees of freedom are nullifiable 
by three elements 3, 4 and 5 which are mounted on the shaft 1 and which 
are all positively connected to the shaft 1. In the illustrated embodiment 
the positive connection of the bottom blade sleeves 2a to 2g to the bottom 
blade shaft 1 is provided firstly by the engagement of a form fitting key 
4 into a longitudinal groove 10 in the bottom blade shaft 1 and the 
engagement of the form fitting key 4 in a longitudinal groove 9 in the 
bottom blade sleeves 2a to 2g, and secondly by the engagement of a screw 
threaded ring 3 by means of an external screw thread 12 thereon into an 
internal screw thread 11 in each bottom blade sleeve 2a to 2g and the 
engagement of a projection 6 of the screw threaded ring 3 into a 
longitudinal T-groove 7 in the bottom blade shaft 1 (FIGS. 1, 2 and 3). 
The positive connection of the screw threaded ring 3 with respect to the 
bottom blade shaft 1 in the axial direction is achieved by the projections 
6 of the screw threaded rings 3, which engage into the longitudinal 
T-groove 7, and fitting members 5 which are disposed between the 
projections 6 on the screw threaded rings. Each of the first one and the 
last one of the fitting members 5 is connected to the bottom blade shaft 1 
by for example a screw connection (not shown in the drawing) in the 
longitudinal T-groove 7. 
All the screw threaded rings 3 are positively connected to the bottom blade 
shaft 1 (FIG. 1) by the arrangement of each screw threaded ring 3 with its 
respective projection 6 in the longitudinal groove 7 in the bottom blade 
shaft 1, and the fitting members 5 which are disposed in the longitudinal 
groove 7 between the individual screw threaded rings 3. The form fitting 
key 4 which is disposed in the longitudinal groove 10 in the bottom blade 
shaft 1 is mounted for axial displacement in the groove 7, so that, 
depending on its position, it is either in engagement by means of a cam 8 
thereof with the bottom blade sleeve 2 in the longitudinal grooves 9 
thereof, or alternatively is not in engagement with the bottom blade 
sleeve 2, so that in the last-mentioned case the cam 8 is then disposed in 
an annular recess 13 in the bottom blade sleeve 2 (FIGS. 1, 2A and 2B). 
Moreover, to improve its function, the cam 8 is formed with a cam front 
taper portion 32, to which more detailed reference will be made 
hereinafter. Radial web portions 15 which serve as bottom blades are 
formed by machining radial grooves 14 in the bottom blade sleeves 2. 
As can also be seen from FIGS. 1, 2A and 2B, for the purposes of providing 
relative rotational movement between the bottom blade sleeves 2a to 2g and 
the bottom blade shaft 1, retaining means are disposed around a shaft 16; 
said retaining means comprising, for each sleeve, a displacement sleeve 
17, a hub 18 which is disposed thereon and which is mounted so as to be 
axially resilient and displaceable in traction and compression coil 
springs 19, a lever arm 20 on the hub 18, a lever arm surface 23 on the 
lever arm 20, a shell member 21 with a friction lining 22 mounted thereon, 
a respective one of cylinders 25a to 25g arranged beside the lever arm 20, 
and a respective one of pressure rollers 24a to 24g which are in turn 
disposed on said cylinders. 
Disposed above and below the bottom blade sleeves 2a to 2g are guide 
rollers 26 and 27 which come into contact with the web of material 28 for 
the purposes of guiding the web of material (FIG. 2B). 
Top blades 29 are arranged for pivotal movement, by means of a lever arm 
30, about a pivot axis indicated at 31. As can be more clearly seen from 
FIG. 4, the bottom blade shaft 1 is mounted so as to be axially and 
radially fixed by means of a cone member 40 thereof received in a mounting 
cone member 41, while it is held by means of a shaft cone member 30 in a 
mounting cone member 36 which is axially adjustable by means of axial 
adjustment means 37. Cone member shafts 49 and 50 are mounted rotatably in 
respective roller bearings 38 and 42 which in turn are carried in machine 
frame members 47 and 48. A disc 33 which is axially displaceably mounted 
on the bottom blade shaft 1 is positively connected to the form fitting 
key 4. The disc 33 is in turn engaged by a forked lever 34 which is 
mounted pivotally on a pivot axis member 35. Disposed on the cone member 
shaft 50 is a belt pulley 43 which can be coupled and uncoupled by way of 
a magnetic clutch 44, while a further magnetic clutch 45 which is 
connected to a servo motor 46 is disposed on the same shaft 50 beside the 
belt pulley 43. 
In operation, once the machine provided with the web cutting means has been 
set in operation, the machine guides the web of material 28 originating 
from a winding-off station (not shown) by the guide roller 26 over the 
bottom blade shaft 1 which is provided with the bottom blade sleeves 2a to 
2g, to the guide roller 27. In doing this, the web of material 28 is drawn 
in the direction of movement between the top blade 29 and the bottom blade 
sleeves 2a to 2g, but into a series of correspondingly narrower webs of 
material and subsequently wound up again in a winding station (not shown). 
If it is desired to produce a web width which does not correspond to a 
multiple of the pitch of the radial web portions 15, it is necessary to 
modify the spacing of the bottom blade sleeves 2a to 2g relative to one 
another, to correspond to the desired change in the cut widths of the web 
of material. If for example a change in the width of only 1.2 mm of the 
cut web of material is to be effected, the following adjustment operation 
is effected in the region of the bottom blade sleeves 2a and 2b shown in 
FIG. 4, carrying out the following adjustment steps. 
The drive belt pulley 43 of the bottom blade shaft 1 is uncoupled by the 
magnetic clutch 44. The magnetic clutch 45 drivingly connects the servo 
motor 46 to the bottom blade shaft 1 by way of the cone member shaft 50 
(FIG. 4). Thereupon, the web of material 28 to be cut is removed from the 
region of the bottom blade sleeves 2a to 2g and the corresponding top 
blades 29 (FIG. 2A). The cylinder 25b which is operable in respect of the 
bottom blade sleeve 2b then presses the associated lever arm 20 towards 
the bottom blade shaft 1 by means of the associated pressure roller 24b 
shown in FIG. 4, by way of the associated lever arm surface 23 (FIGS. 2a 
and 2b). When this is done, the hub 18 rotates on the displacement sleeve 
17 carried by the shaft 16. In this rotary movement, the coil compression 
and torsion spring 19 is stressed. The friction lining 22 which is secured 
to the shell member 21 is thereby pressed by the cylinder 25b onto the 
bottom blade sleeve 2b so that the bottom blade sleeve 2b is retained 
against rotary movement. The disc 33 which is engaged with the form 
fitting key 4 is so pivoted (by pivotal movement of the forked lever 34 
which is engaged with the disc 33 and which pivots about the pivot axis 
member 35), in such a way that the fitting key 4 is displaced axially by 
such a distance that the cams 8 of the fitting key 4 engage into the 
associated annular recesses 13 in the bottom blade sleeves 2a to 2g. 
For the sake of improved comprehension of the description of operation of 
the apparatus, reference is made at this point to the possible 
nullification of the two degrees of freedom; `rotary movement` and `axial 
movement`, such nullification being possible by means of two components 
which are independent of each other in regard to their function, one of 
said components nullifying the possible rotary movement and the other said 
component nullifying the possible axial movement. Of these two degrees of 
freedom, which have just been briefly set out hereinbefore, once again the 
degree of freedom relating to rotary movement about the longitudinal axis 
is liberated by the sequence of operations just described hereinbefore. In 
the course of the rotary movement of the bottom blade shaft 1 by means of 
the servo motor 46, which is effected, all the bottom blade sleeves 2a to 
2g, with the exception of the bottom blade sleeve 2b, rotate with the 
bottom blade shaft 1. The bottom blade sleeve 2b which does not rotate 
since it is retained by the associated friction lining 22 is axially 
adjusted in the desired manner, by way of its internal screw thread 11 and 
the and the external screw thread 12 on the associated screw threaded ring 
3, according to the screw thread pitch and according to the number of 
revolutions of the bottom blade shaft 1. The relative rotary movement 
between the bottom blade shaft 1 and the bottom blade sleeve 2b which is 
being adjusted is terminated with one of the longitudinal grooves 9 in the 
bottom blade sleeve 2b over the form fitting key 4. 
As can be seen from FIGS. 2A and 2B, the bottom blade sleeves 2a to 2g 
contain a finite number of longitudinal grooves 9, there being eight 
longitudinal grooves 9 in the illustrated embodiment. The pitch of the 
internal screw thread 11 of the bottom blade sleeves 2a to 2g and of the 
external screw thread 12 of the associated screw threaded rings 3 is 1.6 
mm, in the embodiment given by way of example. The following example of 
calculations is now given, in conjunction with the foregoing description, 
in order further to disclose the concept of the invention, the calculation 
being as follows, based on the above-mentioned change in the spacing of 
the bottom blade sleeves of 1.2 mm: 
The screw thread pitch of 1.6 mm is multiplied by the number of 
revolutions, namely 0.75, of the bottom blade shaft 1, giving a change in 
the spacing between the bottom blade sleeves 2a and 2b, of 1.2 mm. Any 
axial adjustment of the bottom blade sleeve 2b, calculated in this manner, 
can thus be effected. Thereafter the form fitting key 4 is axially 
displaced, with the disc 33, by means of the forked lever 34, until the 
cams 8 of the form fitting key 4 are re-engaged in one of the longitudinal 
grooves 9 in the bottom blade sleeves 2. Any angular misalignment which 
may occur between the longitudinal grooves 9 in the bottom blade sleeves 
2a to 2g and the form fitting key 4 is compensated by the cam front taper 
portions 32 of the cams 8, by means of the centering action which will be 
understood by and readily apparent to the man skilled in the art from FIG. 
3. 
The axial displacement of the bottom blade sleeve 2b is transmitted to the 
associated friction lining 22 and the shell member 21 and thus to the 
lever arm 20, the hub 18 being axially displaced over the same distance on 
the displacement sleeve 17. When the lever arm 20 is pivoted away, the hub 
18 is returned to its central and outward position by the coil compression 
and torsion springs 19. 
This therefore terminates the width adjustment of the cutting apparatus, by 
a distance of 1.2 mm, by means of the adjusting device so that the web of 
material 28 to be cut can now be drawn into the apparatus and subsequently 
cut. 
Thus, stated briefly, the foregoing disclosure of the concept of the 
invention provides the possibility of rapid adjustment, with the 
axis-parallel displacement of the bottom blade sleeve considered as a 
resultant of the screw thread pitch and the extent of relative rotation of 
the sleeve with respect to the screw threaded ring. 
Worn or damaged bottom blade sleeves 2 can be replaced as follows: 
The forked lever 34 is taken out of engagement with the disc 33. The 
axially displaceable mounting cone member 36 is taken out of engagement 
with the shaft cone member 39 by the axial adjusting means with lever, 
sleeve and guide 37, and retracted by such a distance that the shaft cone 
member 40 can be extracted from the mounting cone member 41 and the bottom 
blade shaft 1, with the components 2 to 15 disposed thereon or thereat, 
can be removed from the machine. Means (not shown in the drawings) for 
securing the two outer fitting members 5 are released, and all the bottom 
blade sleeves 2, together with the screw threaded rings 3 and the fitting 
members 5, are drawn from the bottom blade shaft 1. Now, a respective 
fitting member 5 and a fresh bottom blade sleeve 2 with screw threaded 
ring 3 screwed therein are pushed on to the shaft in such a way that the 
projection 6 of the screw threaded ring engages into the longitudinal 
T-groove 7, and one of the longitudinal grooves 9 in the bottom blade 
sleeve 2 engages over the key 4. When all the members 2, 3 and 5 have thus 
been fitted on to the bottom blade shaft 1, the bottom blade shaft 1 can 
be re-installed in the machine. 
Damage to or wear of only one radial web portion 15 does not necessitate a 
change of the bottom blade sleeves 2. With the multiplicity of radial web 
portions 15 provided, all the top blades 29 which are in a position of 
engagement may be displaced by one web portion or even by a plurality of 
web portions. It is only wear of or damage to a large number of radial web 
portions 15 which necessitates in changing the bottom blade sleeves 2. 
The adjusting device according to the invention can permit a substantial 
saving of time when changing the cutting width, and also when changing 
blades on the bottom blade shaft. 
Moreover, the apparatus according to the invention can be installed not 
only on new machines, but may also be applied as a conversion to many of 
the commercially available corresponding types of machine. 
In spite of the simplicity of the adjusting device, this may advantageously 
be used, without disadvantages, on almost all machines which are 
predominantly directed to cutting foils which are very thin and are not 
self-supporting. Moreover, the apparatus according to the invention can 
also facilitate work, because the prolonged physical work which was 
previously involved in the conventional corresponding adjustment 
operation, can be replaced, when using the apparatus according to the 
invention, by simple actuation of switching buttons, to trigger an 
automatic conversion operation which in most cases can be completed in 30 
seconds to 1 minute. It will be appreciated that any modern further 
developments such as for example automatic computing systems may be 
advantageously used in this respect. I claim: