U.S. patent application number 10/184967 was filed with the patent office on 2003-01-02 for deskewing device for corrugated cardboard manufacturing system.
Invention is credited to Bosl, Ulrich, Ruhland, Karl, Spickenreuther, Stefan, Waldeck, Karl.
Application Number | 20030000988 10/184967 |
Document ID | / |
Family ID | 7690207 |
Filed Date | 2003-01-02 |
United States Patent
Application |
20030000988 |
Kind Code |
A1 |
Ruhland, Karl ; et
al. |
January 2, 2003 |
Deskewing device for corrugated cardboard manufacturing system
Abstract
A deskewing device for a moving web of material in a corrugated
cardboard manufacturing system incorporates a plurality of
successive processing units that are equipped with processing
tools, which are movable crosswise to the direction of conveyance
of the web of material. A skew measuring device is provided to
determine the skew of the web of material. It has a first position
sensor, at least one second position sensor, which determine the
transverse position of the web of material at predetermined
longitudinal positions. A control unit is used to calculate from
the data of the position sensors the skew of the web of material
and the transverse position of the processing tools is corrected
accordingly.
Inventors: |
Ruhland, Karl; (Pfreimd,
DE) ; Bosl, Ulrich; (Hirschau, DE) ; Waldeck,
Karl; (Etzenricht, DE) ; Spickenreuther, Stefan;
(Leuchtenberg, DE) |
Correspondence
Address: |
BROWDY AND NEIMARK, P.L.L.C.
624 NINTH STREET, NW
SUITE 300
WASHINGTON
DC
20001-5303
US
|
Family ID: |
7690207 |
Appl. No.: |
10/184967 |
Filed: |
July 1, 2002 |
Current U.S.
Class: |
226/20 ;
271/227 |
Current CPC
Class: |
B31F 1/2836 20130101;
B65H 23/038 20130101; B65H 23/0204 20130101 |
Class at
Publication: |
226/20 ;
271/227 |
International
Class: |
B65H 043/08; B65H
007/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 30, 2001 |
DE |
101 31 833.2 |
Claims
What is claimed is
1. A deskewing device for a moving web of material (2), especially
a sheet of paper in a paper processing machine, such as, e.g., a
corrugating machine, comprising a) a web of material (2) to be
transported along a desired direction of conveyance (3) and
transported along an actual direction of conveyance (46); b) at
least one processing unit (4, 5, 6, 7, 8) for processing the web of
material (2) wherein the at least one processing unit (4, 5, 6, 7,
8) incorporates at least one processing tool (11, 24, 25, 26, 27,
35), i) which is movable crosswise to the desired direction of
conveyance (3) by means of an actuating drive (30), ii) which can
be brought into engagement with the web of material (2), and iii)
which is disposed at an actual transverse position yIST.sub.w and
at a longitudinal tool position x.sub.w; c) a skew measuring device
for determining the actual direction of conveyance (46) of the web
of material (2), wherein the skew measuring device incorporates i)
at least one first position sensor (40, 40'; 12) disposed at a
first longitudinal the web of material (2), and ii) at least one
second position sensor (40; 40'; 40") disposed at a second
longitudinal position x.sub.s2 to determine a second transverse
position y.sub.s2 of the web of material (2), and d) a control unit
(43), i) which is connected in a data-transferring manner to the at
least one first position sensor (40; 40'; 12), the at least one
second position sensor (40; 40'; 40"), and the at least one
actuating drive (30), and ii) which is designed in such a way that
its actual direction of conveyance (46) is determined from the
first transverse position y.sub.s1 and second transverse position
y.sub.s2 of the web of material (2), that the desired transverse
position ySOLL.sub.w of the at least one processing tool (11, 24,
25, 26, 27, 35) is determined from that actual direction of
conveyance (46), and the at least one actuating drive (12, 30) for
shifting the corresponding processing tool (11, 24, 25, 26, 27, 35)
into the desired transverse position ySOLL.sub.w is actuated.
2. A device according to claim 1, wherein the web of material (2)
has two lateral edges (9).
3. A device according to claim 2, wherein the position sensors (40;
40'; 12, 40") are designed such that they determine the transverse
position of at least one edge (9) of the web of material (2).
4. A device according to claim 3, wherein the position sensors (40;
40'; 12, 40") measure the transverse position of both edges (9) of
the web of material (2).
5. A device according to claim 1, wherein the actuating drive (30)
incorporates a drivable threaded spindle (29).
6. A device according to claim 5, wherein the at least one
processing tool (11, 24, 25, 26, 27, 35), to shift it crosswise,
can be coupled to the threaded spindle (29).
7. A device according to claim 2, wherein a processing unit (4) is
designed as a unit for cutting the edges (9) of the web of material
(2).
8. A device according to claim 7, wherein the unit for cutting the
edges (9) incorporates cutters (11) that are positionable by a
cutter actuating drive (12) into a predetermined crosswise cutter
position y.sub.M.
9. A device according to claim 8, wherein the cutter actuating
drive (12) forms the at least one first position sensor (12).
10. A device according to claim 1, wherein the at least one first
position sensor (40; 40'; 12) and the at least one second position
sensor (40; 40'; 40") are disposed at different longitudinal
positions x.sub.s1 and x.sub.s2 of the web of material (2).
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention is concerned with a deskewing device
for a moving web of material, especially a sheet of paper, in a
paper processing machine, such as, e.g., a corrugating machine.
[0003] 2. Background Art
[0004] In corrugated cardboard manufacturing systems, inaccuracies
in the guide means for the various webs of material can cause the
webs of material to move askew relative to a desired direction of
conveyance. A deskewing device is known from U.S. Pat. No. 5 906
305, wherein a pendulum-style roller is used to correct the skew of
the moving web of material. Existing systems in particular are not
easily retrofitted with compensating devices of this type.
SUMMARY OF THE INVENTION
[0005] The present invention has as its aim to create a device
whereby the skew of a moving web of material in a paper processing
machine can be detected and compensated for in the simplest manner
possible.
[0006] This aim is attained in a deskewing device for a moving web
of material, especially a sheet of paper in a paper processing
machine, such as, e.g., a corrugating machine, with a web of
material to be transported along a desired direction of conveyance
and transported along an actual direction of conveyance; with at
least one processing unit for processing the web of material
wherein the at least one processing unit incorporates at least one
processing tool, which is movable crosswise to the desired
direction of conveyance by means of an actuating drive, which can
be brought into engagement with the web of material, and which is
disposed at an actual transverse position yIST.sub.w and at a
longitudinal tool position x.sub.w; with a skew measuring device
for determining the actual direction of conveyance of the web of
material, wherein the skew measuring device incorporates at least
one first position sensor disposed at a first longitudinal position
x.sub.s1 to determine a first transverse position y.sub.s1 of the
web of material, and at least one second position sensor disposed
at a second longitudinal position X.sub.s2 to determine a second
transverse position y.sub.s2 of the web of material; and with a
control unit, which is connected in a data-transferring manner to
the at least one first position sensor, the at least one second
position sensor, and the at least one actuating drive, and which is
designed in such a way that its actual direction of conveyance is
determined from the first transverse position y.sub.s1 and second
transverse position y.sub.s2 of the web of material, that the
desired transverse position ySOLL.sub.w of the at least one
processing tool is determined from that actual direction of
conveyance, and the at least one actuating drive for shifting the
corresponding processing tool into the desired transverse position
ySOLL.sub.w is actuated. The gist of the invention is that the
transverse position of a moving web of material is determined at
two different successive longitudinal positions and the skew of any
other randomly selected longitudinal position can be determined
from it. At the processing units that are disposed along the web of
material, the processing tools are automatically corrected
regarding their position according to the determined lateral
deviation. It is thus not necessary to shift the processing units
crosswise in their entirety. Additionally, it is possible to
determine the required compensation for the skew as accurately as
possible.
[0007] Additional characteristics and details of the invention will
be come apparent from the description of three embodiments with the
aid of the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 shows a schematic top view of an inventive device
according to a first embodiment,
[0009] FIG. 2 shows a side view of the device according to FIG.
1,
[0010] FIG. 3 shows a top view of the device according to FIG.
1
[0011] FIG. 4 shows a front view according to the viewing arrow IV
in FIG. 2,
[0012] FIG. 5 shows a schematic illustration of the mode of
operation of the device according to FIG. 1,
[0013] FIG. 6 shows a schematic top view of an inventive device
according to a second embodiment,
[0014] FIG. 7 shows a top view of the device according to FIG.
6,
[0015] FIG. 8 shows a schematic top view of a device according to a
third embodiment, and
[0016] FIG. 9 shows a top view of the device according to FIG.
8.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0017] A first embodiment of the invention will be described below
with reference to FIGS. 1 through 5. A corrugated cardboard
manufacturing system incorporates a longitudinal cutting and
corrugating machine 1 through which a corrugated cardboard web 2 is
guided along a desired direction of conveyance 3. The machine 1
incorporates, along the direction of conveyance 3, an edge-cutting
station 4, a first corrugating station 5, a second corrugating
station 6, as well as a first longitudinal cutting station 7, as
well as a second longitudinal cutting station 8.
[0018] The edge cutting station 4 incorporates, in the region of
the lateral edges 9 of the corrugated cardboard web 2, two rotating
cutters 11 that are pivotable around a vertical pivoting axis 10
and disposed below the corrugated cardboard web 2 and can be
brought into engagement with the corrugated cardboard web 2. The
cutters 11 are shiftable crosswise to the direction of conveyance 3
by means of an assigned actuating drive 12. The cutters 11, as well
as the actuating drives 12, are supported across from side walls 13
of a machine support 14. The detailed design of the edge cutting
station 4, which permits the cutting of endless edge strips during
format changes, is known from U.S. Ser. No. 08/503 425.
[0019] The corrugating stations 5 and 6 have pairs of tool beds 15,
16, as well as 17, 18, that are supported between opposing side
walls 13. The tool beds 15 and 16, as well as 17 and 18, are
disposed above one another in pairs, namely approximately
mirror-symmetrically to the corrugated cardboard web 2. The tool
beds 15 through 18 each are pivotable around a horizontal pivoting
axis. Disposed on the sides of the tool beds 15 through 18 that
face the corrugated cardboard web 2, are guide rails 19, on which
tool holders 20 through 23, which are again assigned to one another
in pairs, are disposed horizontally and shiftable crosswise to the
direction of conveyance 3. Provided on the upper tool holders 20
and 21 are corrugating tools 24 and 25 that work together with
respective counterpart corrugating tools 26 and 27 that are
disposed underneath them on the tool holders 22 and 23. The tools
24 through 27 are drivable by means of belt drives 28. The
corrugating stations 5, 6, additionally incorporate a rotatably
mounted threaded spindle 29 that extends perpendicular to the
direction of conveyance 3 and is drivable by means of a spindle
motor 30 connected to the threaded spindle 29. The individual
corrugating tools 24 through 27, of which a plurality are disposed
on each given tool holder 20 through 23, can be coupled to the
corresponding threaded spindle 29 to effect a shifting of the
corresponding corrugating tool 24 through 27. In this manner one
threaded spindle 29 may be used to shift a plurality of tools 24
through 27 disposed along a threaded spindle 29, either
individually or all of them together. Reference is made to U.S.
Ser. No. 09/924 098 of the applicant's for the detailed design of a
1-spindle positioning unit. Regarding the detailed design of the
corrugating stations 5 and 6, as well as the longitudinal cutting
stations 7 and 8, reference is made to U.S. Ser. No. 09/203
575.
[0020] The longitudinal cutting stations 7 and 8 incorporate, below
the corrugated cardboard web 2, in a manner that matches the design
of the corrugating stations 5 and 6, pivotable tool beds 31 and 32,
on which, disposed on tool holders 33, 34 and shiftable crosswise
to the direction of conveyance 3, cutters 35 are provided that are
drivable by means of a corresponding belt drive 28. The cutters 35
can be brought into engagement with the corrugated cardboard web 2
and work together with rotatably driven brush rollers 36, 37 that
are disposed above the corrugated cardboard web when the cutters 35
are immersed in the corrugated cardboard web. Regarding the
transverse travel of the cutters 35, reference is made to the
description of the corrugating stations 5 and 6.
[0021] A means for measuring a skew of the corrugated cardboard web
2 incorporates two cross supports 38 and 39 that are connected to
the side walls 13 and extend crosswise to the direction of
conveyance 3 above the corrugated cardboard web 2. The cross
support 3 8 is disposed at the end of the edge cutting station 4
that is located in the direction of conveyance 3. The cross support
39 is disposed at the beginning of the longitudinal cutting station
7. Disposed on the cross supports 38 and 39, approximately above
the edges 9 of the web of material 2, are cameras 40 that have a
recording range 41. The cameras 40 are commercially available
cameras, especially digital cameras, that are suitable for
subsequent image processing to measure the position of the edges 9.
The cameras 40 are connected via signal lines 42 to a control unit
43 which, in turn, is connected via signal lines 44 to the spindle
motors 30.
[0022] The following is a description of the deskewing of the
corrugated cardboard web 5, with reference especially to FIG. 5. It
should be noted that FIG. 5 is not true to scale and represents a
significant simplification of the machine 1 in order to better
explain its operation. The desired movement 45 of a corrugated
cardboard web 2 through the machine 1 extends parallel to the
desired direction of conveyance 3. Malfunctions in the corrugated
cardboard manufacturing system may cause the corrugated cardboard
web 2 to travel along an actual direction of conveyance 46 that is
askew and not parallel to the desired direction of conveyance 3.
FIG. 5 shows only the cameras 40 that are disposed above the right
edge 9 in the direction of conveyance 3, and two cameras 40 are
also disposed in the region of the left edge 9. The cameras 40 are
disposed at two known longitudinal positions x.sub.s1 and x.sub.s2.
With the cameras 40 the transverse position of the edge 9 is
determined, which is referred to as y.sub.s1 and y.sub.s2. From
this data, i.e., two known points that are given in a Cartesian
coordinate system, the position of the edge 9 can be calculated at
any other randomly selected longitudinal position. Any inaccuracies
can be eliminated in such a way that the determined position data
of the left edge 9 and right edge 9 are compared to one another.
The measured data from the cameras 40 are routed via the lines 42
to the control unit 43, which calculates the travel of the
corrugated cardboard web 2. From the measured data, the desired
transverse position ySOLL.sub.w, that corresponds to the skewed
travel of the corrugated cardboard web 2 is calculated for the
given tools 24 through 27 and 35. A corresponding control signal is
subsequently routed via the lines 44 to the corresponding motor 30,
which, via the threaded spindle 29, shifts the corresponding tool
from the actual transverse position yIST.sub.w into the desired
transverse position ySOLL.sub.w. As a rule, all tools 24 through 27
and 35 that are assigned to one threaded spindle 29 are moved all
at once, based on the required deskewing. Since the required
corrections, as a rule, are relatively small shifting movements,
the tools 24 through 27 and 35 may also be moved crosswise while
they are in engagement with the corrugated cardboard web 2. The
placement of the stations 4 through 8 has the particular advantage
that the edge cutting station 4 precedes the corrugating stations 5
and 6 and longitudinal cutting stations 7 and 8. This enables the
cameras 40 to follow the course of a cut edge 9, which has a much
clearer and straighter contour than an uncut edge 9. Utilizing the
measuring data from two cameras that are disposed at one level of
the corrugated cardboard web 2 is particularly important when a
change in the format occurs and the outer contour of the edge 9,
therefore, does not extend straight but curved. By utilizing the
data of the position of the left and right edge 9 of the corrugated
cardboard web 2 it is possible to precisely determine the skew of
the corrugated cardboard web 2 and calculate in advance the
deviation of a desired transverse position from an actual
transverse position at any random longitudinal position of the
corrugated cardboard web 2. With the skew measuring device it is
additionally also possible to compensate for a lateral displacement
of the corrugated cardboard web 2. While, in this case, the actual
direction of conveyance 46 of the corrugated cardboard web 2 does
run parallel to the desired direction of conveyance 3, the
corrugated cardboard web 2 does not move centrically through the
machine 1 but is offset crosswise. The correction of such a lateral
web displacement can also be performed with the inventive device
without changes to the same. The transverse position of the
corrugated cardboard web 2 can also take place by means of a
marking that is provided on the corrugated cardboard web 2, e.g.,
an imprinted line.
[0023] A second embodiment of the invention will be described
below, with reference to FIG. 6 and 7. Identical parts will be
given the same reference numerals as in the first embodiment, and
reference is hereby made to that description. Parts that are
different in their design but have the same function are given the
same reference numeral with a prime mark. The main difference
compared to the first embodiment lies in the fact that the edge
cutting station 4 is located downstream from the stations 5 through
8. Two cameras 40' are accordingly disposed before the first
station 5, as well as between the stations 6 and 7 which, as in the
first embodiment, record the position of the edge 9 of the
corrugated cardboard web 2. Placing station 4 after the stations 5
through 8 results in the cameras 40 each recording one uncut edge
9. The placement according to the second embodiment is used
particularly when, for operational reasons, the edge cutting must
take place after the corrugating stations 5 and 6 and longitudinal
cutting stations 7 and 8.
[0024] A third embodiment of the invention will be described below
with reference to FIG. 8 and 9. Identical parts will be given the
same reference numerals as in the first embodiment, and reference
is hereby made to that description. Parts that are different in
their design but have identical functions are given the same
reference numerals with two prime marks. As in the first
embodiment, the stations 4 through 8 are disposed successively
along the direction of conveyance 3. The main difference compared
to the first embodiment is that no provision is made for a first
pair of cameras 40 in the direction of conveyance 3. The function
of the first two position sensors is assumed by the actuating
drives 12 of the edge cutting station 4. The actuating drives 12
are connected via lines 42 to the control unit 43. The control unit
43 at all times has information regarding at which transverse
positions the cutters 11 are disposed. The transverse positions of
the cutters 11 thus correspond to the transverse position data
y.sub.s1 of the front camera pair 40 in the first embodiment. From
that transverse position data, as well as the transverse position
data from the subordinate camera pair 40", the skew of the
corrugated cardboard web 2 is determined by the control unit 43.
This embodiment has the advantage that only two cameras 40" are
needed and not four cameras 40, as in the first embodiment.
* * * * *