U.S. patent application number 12/532713 was filed with the patent office on 2010-04-29 for cross-cutting device.
This patent application is currently assigned to HOCHLAND NATEC GmbH. Invention is credited to Roland Zeuschner.
Application Number | 20100101392 12/532713 |
Document ID | / |
Family ID | 39523324 |
Filed Date | 2010-04-29 |
United States Patent
Application |
20100101392 |
Kind Code |
A1 |
Zeuschner; Roland |
April 29, 2010 |
CROSS-CUTTING DEVICE
Abstract
The invention relates to a cutting device for cutting
prefabricated transverse seal seams of a tube composed of plastic
film and filled with food, particularly soft cheese, wherein each
transverse seal seam of the continuously supplied film tube to be
processed separates one portion of the food from the next portion,
wherein said device comprises a rotating knife holder provided with
at least one knife blade 22, and wherein the knife blade 22 acts on
a counter bearing 4 when cutting a transverse seal seam, wherein
said knife holder has a heating element for heating the knife blade
22 in a targeted fashion.
Inventors: |
Zeuschner; Roland;
(Argenbuehl, DE) |
Correspondence
Address: |
MILLEN, WHITE, ZELANO & BRANIGAN, P.C.
2200 CLARENDON BLVD., SUITE 1400
ARLINGTON
VA
22201
US
|
Assignee: |
HOCHLAND NATEC GmbH
heimenkirch
DE
|
Family ID: |
39523324 |
Appl. No.: |
12/532713 |
Filed: |
March 12, 2008 |
PCT Filed: |
March 12, 2008 |
PCT NO: |
PCT/EP2008/052934 |
371 Date: |
September 23, 2009 |
Current U.S.
Class: |
83/171 ; 83/346;
83/348 |
Current CPC
Class: |
Y10T 83/04 20150401;
B65B 61/10 20130101; B26D 7/10 20130101; B26D 1/626 20130101; Y10T
83/4844 20150401; Y10T 83/4838 20150401; Y10T 83/293 20150401 |
Class at
Publication: |
83/171 ; 83/346;
83/348 |
International
Class: |
B65B 61/08 20060101
B65B061/08; B65B 61/10 20060101 B65B061/10 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 29, 2007 |
DE |
10 2007 015 624.5 |
Claims
1. Cutting device for cutting pre-fabricated transverse seams of a
plastic-film sleeve that is filled with food, in particular with
processed cheese, whereby each transverse seam of the film sleeve
to be processed and continuously fed separates one portion of the
food from the next portion, whereby the device has a rotating knife
holder equipped with at least one cutting blade (22), and whereby
the cutting blade (22) strikes against an opposing bearing (4) when
cutting a transverse seam, characterized in that the knife holder
has a heating element for targeted heating of the cutting blade
(22).
2. Cutting device, according to claim 1, wherein the heating
element is arranged in such a way that a majority of its heat
output is fed to the cutting blade (22) and heats the latter more
greatly than the knife holder.
3. Cutting device according to claim 1, wherein the cutting blade
(22) is held elastically on the knife holder in the cutting
direction.
4. Device according to claim 1, wherein the knife holder is a blade
cylinder (2), which is equipped with several, in particular with
four, cutting blades (22), whereby a counter-rotating opposing
roller (4) forms the opposing bearing.
5. Cutting device according to claim 1, wherein the cutting blade
(22) rests on a support surface, whereby the heating element is
arranged in a hole (30) of the solid material that forms the
support surface.
6. Cutting device according to claim 5, characterized by a separate
receiving part (23) for holding in each case a cutting blade (22),
which is held in a radially oriented guideway of the knife holder
and is pressed down by springs (24).
7. Cutting device according to claim 5, characterized by the fact
that the material of the knife holder forms the support surface
(27), whereby the support surface (27) is oriented in particular
outside of the radials of the blade cylinder (2).
8. Cutting device according to claim 7, wherein the cutting blade
(22) is formed by a flat material, in particular made of hard
metal, with a rectangular cross-section, whereby the four edges of
the flat material in each case form a cutting edge (29).
9. Cutting device according to claim 1, wherein the heating element
produces a temperature on the cutting edge (29) of the cutting
blade of over 80.degree. C., in particular of about 100.degree.
C.
10. Cutting device according to claim 1, wherein the knife holder
is provided with a sensor to measure temperature and/or with a
cooling system.
11. Cutting device according to claim 1, wherein the cutting edge
(29) of the cutting blade (22) is such that in particular it is
shorter than the transverse seam, so that after cutting, film arms
remain or a perforation seam is produced.
Description
CROSS-CUTTING DEVICE
[0001] This invention relates to a cutting device for cutting
pre-fabricated transverse seams of a plastic-film sleeve that is
filled with food, in particular with processed cheese, whereby each
transverse seam of the film sleeve to be processed and continuously
fed separates one portion of the food from the next portion,
whereby the device has a rotating knife holder equipped with at
least one cutting blade, in particular in the form of a blade
cylinder, and whereby the cutting blade strikes against an opposing
bearing, in particular a counter-rotating opposing roller, when
cutting a transverse seam.
[0002] Such cutting devices are known from, for example, the
production of individually packaged processed cheese slices. Such a
process for production and the corresponding device are indicated
in, for example, DE 42 04 357 A1. In this case, processed cheese is
filled into a film sleeve that is sealed at a longitudinal seam,
and this sleeve is then rolled flat and subsequently cooled. In
this case, the cheese belt surrounded by film is cut into portions
only after cooling ("cold squeezing") by the cheese being squeezed
at cross strips and the film sleeve from which cheese is removed
being sealed at these cross strips by exposure to the action of
heat. With modern machines, this squeezing takes place as long as
the cheese mass is still hot ("hot squeezing"). To make individual
slices from this "chain" or this belt of slices attached to one
another, the seams formed by the cross-seals that are several
millimeters wide are cut through with the knife or knives of the
cutting device. In this case, such cutting devices can be designed
in the manner of guillotines. The use of blade cylinders, whose
flexible cutting blades cut on the hardened surface of an opposing
roller, has proven especially advantageous, however, whereby the
chain of the individual slices is fed through the two rollers.
[0003] A drawback of the known cutting devices is that the cutting
blades become blunt after a certain number of cuts and have to be
replaced. This is due to the fact that the double-layer film, which
in most cases consists of polypropylene and is about 50 micrometers
thick, is relatively tough in the state to be cut. The blunting of
the cutting blades affects the service life negatively and reduces
the productivity of the machine. Moreover, the cutting blades that
are to be replaced are a cost factor in and of themselves, to which
the assembly process with the expensive adjustment is added.
[0004] The object of the invention is now to propose a cutting
device that in a simple design, which makes possible a modular type
of construction and a simple assembly, ensures an extended service
life because of less use of the cutting blades.
[0005] This object is achieved by the cutting device according to
claim 1. Advantageous embodiments are mentioned in the
subclaims.
[0006] An essential idea of the invention is to provide the knife
holder with a heating element, which causes a targeted heating of
the cutting blades. In this case, as a "targeted heating of the
cutting blades," such a heating is meant that goes beyond the
normal operating temperature of the cutting blades and that
primarily does not lead to a noteworthy heating of the knife
holder, which because of heat expansion would irreversibly alter
its geometry with respect to its smooth operation. In particular,
the heating according to the invention is also not so great that
the film at the transverse seam is opened by melting. The
temperature of the cutting blade thus advantageously remains below
the melting temperature of the plastic used for the film.
[0007] On this point, it can be emphasized that the procedure
according to the invention is distinguished from the prior art, as
it is disclosed in, for example, DE 39 20 867 A1. There, in a
single operating step, the product is squeezed in the area of the
sleeve that is to be cut, is transverse to this area and is cut
here. The knife thus performs sealing and separating at the same
time. At no point does the pre-fabricated transverse seam exist.
Thus, this procedure, in the sleeve that is present here and filled
with food, in particular with processed cheese, is not possible,
since in the manufacturing procedure, first a chain of connected
portions is formed and has to be fed to a cooling process. Only the
thus pre-manufactured portions are then separated.
[0008] In the additional heating according to the invention, it is
necessary to hold the latter as far as possible from the bearings.
This object can be achieved in that the knife holder is designed so
that the flow of heat is essentially sent to the cutting blades.
This can be affected by the selection of material or the provision
of insulation and/or the installation of a heat trap, for example
in the form of cooling by a corresponding cooling device. It is
especially advantageous, since it is especially simple to achieve,
however, if the heating element is arranged near the cutting blade
and with corresponding heat contact to the cutting blade in such a
way that a large portion of the heat output is fed as directly as
possible to the cutting blade and heats the latter more greatly
than the remaining knife holder.
[0009] In general, the advantage of heating the cutting blade lies
in the fact that the film sleeve that is locally heated for a short
time resists the cutting blade when cutting a reduced resistance,
so that the degree of wear and tear of the cutting blade is reduced
and thus the service life of the cutting device is increased.
Ultimately, the film sleeve that is formed from plastic film, for
example polypropylene, is softer by the heating at the interface
than it is at room temperature, so that it can be cut more easily.
It has been shown that the service life of the cutting blades can
be increased by a multiple in the method according to the
invention. In this case, it has also been shown that it is
advantageous when the heat output and the arrangement of the
heating element are selected so that a temperature of over
80.degree. C., in particular of about 100.degree. C., is produced
on the cutting edge of the cutting blade. Temperatures of up to
130.degree. C. are not ruled out.
[0010] As a heating element, for example, a commercially available
heating cartridge of sufficient size can be used that is held in a
hole made in the knife holder and is supplied with voltage. The
dimensioning of the heating cartridge and its voltage supply can be
adapted according to the geometry of the knife holder. The heat
output of the heating cartridges can be adapted to the application
speed to obtain the desired temperature. Although the measurement
of the current temperature by a corresponding sensor and also its
controllability has a certain advantage, it is not absolutely
necessary. Ultimately, the cutting device cuts "in emergency
operation" even without a heated cutting blade.
[0011] Since it is structurally expensive to minimize undesirable
heat expansions that change the position of the cutting blade and
such changes occasionally cannot be completely avoided, it is
especially advantageous when the cutting blade is held in a
flexible manner on the knife holder, so that the cutting blade can
be flexible in the cutting direction. In this case, the elasticity
is adjusted so that a pressure that is adequate for the cutting
action is maintained. The flexibility according to the invention
can in this case be produced from the cutting blade itself or via
an elastically suspended receiving part in which the cutting blade
is held. Actually, the idea of the cross-cutting device with an
elastically suspended cutting blade is, to a certain extent,
independent of the knife holder with heating element according to
the invention. However, special advantages arise specifically from
the combination of the two ideas.
[0012] One advantage of such flexibility lies primarily in the
associated increase in the tolerance of the cutting blade compared
to a possible maladjustment, which can take place during operation.
This advantage especially has an effect if the knife holder and the
opposing bearing are designed as rollers, and the cutting blade
during cutting has to be lined up exactly against the smooth and
hardened surface of the opposing roller. In such an arrangement,
any maladjustment produces a gap between the cutting blade and the
surface of the opposing roller, so that the cut cannot be made
completely. With the elastic suspension according to the invention,
which advantageously also still allows a little play in other
degrees of freedom, such a formation of gaps is avoided. As a
result, the flexibility produces a certain tolerance against
maladjustment, and even reduces the expense in the assembly of
cutting blades.
[0013] With respect to an especially high production speed, it is
advantageous if the knife holder is designed as a rotating means,
in particular in the form of the already mentioned blade cylinder,
whereby the latter is equipped in particular with several,
advantageously with four, cutting blades. In the case of such a
blade cylinder, it is then advantageous if the opposing bearing is
formed from a counter-rotating opposing roller, which has, in
particular, a surface made of hard metal. The opposing roller can
have a somewhat different diameter from the blade cylinder. To
eliminate another drive, it is especially advantageous if the blade
cylinder drives the opposing roller over boundary areas that roll
off on one another. With such a drive that has little slack or with
a somewhat different roller diameter, the result is that the
cutting blade does not always press down on the same spot on the
opposing bearing, so that it results in a uniform use of the
opposing bearing. Advantageously, the bearing of the opposing
roller is also somewhat prestressed to produce the corresponding
contact pressure and to offset tolerances.
[0014] In the case of such a blade cylinder, there are two
advantageous possibilities of holding the cutting blades: in one
case, the fastening for a cutting blade is implemented as a
separate receiving part that is held in a radially-oriented
guideway in the blade cylinder and is pressed down by springs. Such
a design offers several possibilities relative to the adjustment
parameters; the adjustment is still expensive because of the high
number of parts. In an especially simple alternative, the material
of the blade cylinder forms the actual support surfaces. The
support surfaces are recessed to a certain extent in the material
of the blade cylinder, whereby correspondingly adjusted support
edges can be provided. The cutting blades then need to be put only
on these support surfaces and be fastened. To obtain elasticity,
the support surfaces are somewhat shorter than the cutting blades,
so that the latter flex with their extension when held
accordingly.
[0015] Advantageously, the cross-sealing during cutting is not
completely separated, but rather perforated to a certain extent, so
that after cutting, film arms remain, at which the chain adheres,
and have to be conveyed a bit further on until the final separation
of the individual links occurs. The final separation then takes
place by, for example, tearing off, by the leading portion, in
particular the cheese slice, being somewhat accelerated in
comparison to the trailing portion. Such a "perforation" can be
produced so that the cutting edge of the cutting blade is shorter
than the transverse seam, so that during cutting, two arms remain
on the edge. To achieve this perforation, grooves can also be
ground into the cutting blades.
[0016] It is also especially advantageous if the blade cylinder and
the opposing roller are combined in a common module that can be
held on the machine and easily replaced. Such a module has the
advantage that the cutting blades are preassembled and can be
adjusted. To make possible the replaceability, the blade cylinder
is equipped with an electrical connection arranged in the drive
shaft, via which connection the supply lines of the heating
element(s) can be put into contact with corresponding cables that
run in the shaft.
[0017] Below, the invention is explained in more detail based on
FIGS. 1 to 4. In this case,
[0018] FIG. 1: shows a section through the cross-cutting
device,
[0019] FIG. 2: shows a cross-cut module with a blade cylinder and
an opposing roller,
[0020] FIG. 3: shows a first embodiment of a blade cylinder,
and
[0021] FIG. 4: shows a second embodiment of a blade cylinder.
[0022] The cut that is depicted in FIG. 1 by a cross-cutting device
shows a cross-cut module 1 (see also FIG. 2) on its end, with a
rotating blade cylinder 2 that is designed as a cross-cutting
cylinder (shown in cut sections) and an opposing roller 4, whose
surface 3 is coated with hard metal. The chain formed by the
interconnecting cheese slices is run between the rollers from above
past a guide plate 17. The cross-cut module 1 is screwed tightly
into an assembly wall 5 of the machine. FIG. 1, moreover, shows the
drive of the blade cylinder 2 over the drive shaft 6, and in this
central hole 7, cables, not shown, are run for the supply of
heating elements. The drive is actuated via a servomotor, not
shown, which acts on the drive shaft 6 via the worm gear 8. The
worm gear 8 is held on the assembly wall 5 via a spacer 9, whereby
the drive shaft 6 is mounted on the assembly wall 5 via a ball
bearing 10.
[0023] The end of the drive shaft 6 has a hole with a splined hub
profile, into which a corresponding splined shaft profile 11 of the
blade cylinder 2 (see FIG. 3) is inserted. On the housing of the
worm gear 8, a holder 12 is provided for an initiator, which
queries the cams 13 of the coupling 14 and thus defines the
position of the cutting blades. The supply voltage for the heating
elements is fed via a slip ring unit 15 and via the supply cables,
not shown, of the blade cylinder 2. FIG. 1 also shows a light
barrier system 18, with which the arrival of a transverse seam is
detected. Corresponding to this arrival, the servomotor is
controlled so that the cutting blades cut through the transverse
seam in the center.
[0024] In FIG. 2, a separate cross-cut module 1 is shown with a
blade cylinder 2 and a counter-rotating opposing roller 3. The
splined shaft profile 11 of the blade cylinder 2 and the electrical
plug-in contact 19 contained therein can be seen. The connector to
the drive shaft thus provides the mechanical and the electrical
coupling of the cross-cut module 1 to the drive. With the
connector, the complete cross-cut module can be removed from the
unit and can be replaced by another module. The drive of the
opposing roller 3 takes place via the edges 20 and 21 of the two
rollers 2 and 3 that roll off on one another. FIG. 2 also shows one
of four cutting blades 22, which are held on the blade cylinder
2.
[0025] Easier to see are the cutting blades 22 from FIG. 3, which
shows a blade cylinder 2. In this embodiment, separate receiving
parts 23 (FIG. 3b), which in each case hold a cutting blade 22 that
extends over the entire active length of the blade cylinder 2, are
arranged in the blade cylinder 2. The cutting blades 22 are held by
screws 25 and adjusted in the receiving part. The receiving parts
23 in each case have a support surface on which the cutting blade
rests over an extensive area and with good heat contact. They are
run into a guideway that is introduced into the solid matter of the
roller 2 and can be moved therein in radial direction. The
receiving parts 23 are pressed down in radial direction by springs
24. The respective cutting blade is held elastically in cutting
direction on the knife holder.
[0026] In FIG. 3b, holes 26 can be seen, and said holes 26 are made
in the receiving parts 23 and in each case accommodate a heating
element for specific heating of the cutting blade 22. In this way,
the heating element is arranged in such a way that a majority of
its heat output is fed to the cutting blade 22 and heats the latter
more greatly than the knife holder.
[0027] In FIG. 4, another type of blade cylinder 2 is shown, which
also has a splined-shaft profile 11 and a connector 19, which,
however, has another type of attachment of the cutting blades 22.
In particular, it can be seen from FIG. 4b that the cutting blades
22 in the plane of a secant are attached perpendicular to the
radius of the roller. To this end, in the solid matter of the knife
holder, support surfaces 27 are formed on which the large-area
cutting blades 22 rest. They are applied to the application edges
on the solid matter and are held by clamping claws 28 at their edge
facing away from the cutting edge 29. In the material of the
roller, in direct proximity to the support surfaces 27, holes 30
are made to hold the heating elements. The cutting edges 22 are
formed from flat material made of hard metal with a rectangular
cross-section, whereby the four edges of the flat material in each
case form a cut edge. A cutting blade thus has four cuts. The flat
material can also be made of HSS or powder-metallurgical
material.
[0028] The elasticity of the cutting blades 22 is ensured by the
fact that they are held on one side and that the support on the
support surface 27 is incomplete. Because of this special holder,
an elasticity in the direction of arrow A and thus also in radial
cutting direction is provided. The direction of travel is
identified with arrow B.
* * * * *