U.S. patent application number 10/513015 was filed with the patent office on 2005-07-14 for method and apparatus for tail threading of a paper web in a finishing machine for paper.
Invention is credited to Ahvenniemi, Vesa, Kinnunen, Jorma.
Application Number | 20050150926 10/513015 |
Document ID | / |
Family ID | 8563854 |
Filed Date | 2005-07-14 |
United States Patent
Application |
20050150926 |
Kind Code |
A1 |
Ahvenniemi, Vesa ; et
al. |
July 14, 2005 |
Method and apparatus for tail threading of a paper web in a
finishing machine for paper
Abstract
A device in a finishing machine for paper is arranged to guide a
paper web along a predetermined path. The traction device (2)
engages a tail of the web or an auxiliary member (6) for
transferring the tail of the web. The device has power transmission
of its own by means of which is moves in relation to a guide (1)
extending in the machine direction. The traction device moves in
relation to the guide by friction contact of one or several drive
wheels (3) with the guide (1). The friction contact plane of the
guide (1) curves in directions perpendicular thereto in accordance
with the travel path of the paper web.
Inventors: |
Ahvenniemi, Vesa; (Helsinki,
FI) ; Kinnunen, Jorma; (Helsinki, FI) |
Correspondence
Address: |
STIENNON & STIENNON
612 W. MAIN ST., SUITE 201
P.O. BOX 1667
MADISON
WI
53701-1667
US
|
Family ID: |
8563854 |
Appl. No.: |
10/513015 |
Filed: |
February 22, 2005 |
PCT Filed: |
April 30, 2003 |
PCT NO: |
PCT/FI03/00340 |
Current U.S.
Class: |
226/92 |
Current CPC
Class: |
D21G 9/0072 20130101;
B41F 13/03 20130101; B65H 2801/84 20130101; B65H 2301/52202
20130101 |
Class at
Publication: |
226/092 |
International
Class: |
B65H 020/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 30, 2002 |
FI |
20020816 |
Claims
1-31. (canceled)
32. A method for tail threading of a paper web in a finishing
machine for paper that is arranged to guide a paper web along a
predetermined path, the method comprising the step of drawing a
tail of the web or an auxiliary member for threading the tail of
the web with a traction device comprising power transmission of its
own by which the traction device moves in relation to a guide
extending in the machine direction, wherein the movement of the
traction device in relation to the guide is attained by a friction
contact of one or several drive wheels of the traction device with
the guide, and wherein the guide has a friction contact plane which
curves in directions perpendicular thereto in accordance with the
travel path of the paper web.
33. The method of claim 32, wherein, in threading, one or several
successively coupled carriages are used as the traction device,
said carriages being articulated to turn with respect to each other
in the plane of curvature of the guide, wherein said one or several
drive wheels are located in a different carriage than the fastening
point of the tail of the web or the auxiliary member for threading
the tail of the web.
34. The method of claim 33, wherein three or several successively
coupled carriages are used, which are articulated to turn with
respect to each other in the plane of curvature of the guide, and
in which at least a power source is positioned in a carriage of its
own.
35. The method of claim 34 wherein the power source comprises a
battery.
36. The method of claim 32 wherein a pressing force of the one or
several drive wheels is attained by counter wheels effective on an
opposite side of the friction contact plane of the guide.
37. The method of claim 32 wherein the friction contact is attained
by means of a belt passed around at least one drive wheel.
38. The method of claim 32 wherein in the tail threading of the web
a lead-in strip that is narrower than the full-width web is first
transferred at least to a section of predetermined length in the
machine direction of the finishing machine, whereafter the lead-in
strip is followed by a full-width web.
39. The method of claim 32 wherein the predetermined path contains
at least one hold point capable of transferring the tail of the web
at a predetermined transfer rate irrespective of the traction
device, and the transfer rate of the hold point of the finishing
machine and the travel speed of the traction device along the guide
are adjusted with respect to each other in such a manner that the
tail of the web drawn with the traction device travels
substantially at the transfer rate of the hold point.
40. The method of claim 39 wherein the tail of the web comprises a
lead-in strip which is directly connected to the traction
device.
41. The method of claim 32 wherein the tail of the web is
transferred simultaneously with the movement of the traction device
and drawn with the traction device via the auxiliary member that
transmits tensile stress.
42. The method of claim 39 wherein the tail of the web is drawn in
the drawing direction with an elastic auxiliary member.
43. The method of claim 32 wherein by means of the traction device
the auxiliary member, which transmits tensile stress, is first
drawn at least to a section of predetermined length in the machine
direction of the finishing machine without a drawing contact to the
tail of the web, and thereafter the tail of the web is drawn on the
same section by means of the auxiliary member transmitting tensile
stress.
44. The method according of claim 32 wherein the guide is utilized
to guide the traction device, and with said traction device the
tail of the web and/or the auxiliary member, at least partly via a
winding path that contains sections curved in opposite
directions.
45. The method of claim 32 wherein the guide is utilized to guide
through at least one coating station the traction device, and with
said traction device the tail of the web and/or the auxiliary
member.
46. The method of claim 32 wherein the guide is utilized to guide
through at least one calendering nip the traction device and with
said traction device the tail of the web and/or the auxiliary
member.
47. The method of claim 32 wherein the guide is utilized to guide
from an unwinder through the entire finishing machine to a reel-up,
the traction device and with said traction device the tail of the
web and/or the auxiliary member.
48. The method of claim 32 wherein the tail comprises a lead-in
strip which is spread into a full-width web at the same time as it
is drawn by the traction device.
49. The method of claim 32 wherein the guide is cooled down by a
cooling medium at least for a part of its length.
50. The method of claim 32 wherein the speed of the traction device
is adjusted during threading by remote control.
51. The method of claim 32 further comprising the step of measuring
the force affecting the fastening point of the tail of the web or
the auxiliary member in the traction device during threading.
52. An apparatus for tail threading of a paper web in a finishing
machine for paper, in which the paper web is arranged to travel
along a predetermined path, wherein the apparatus comprises a
threading device comprising a guide extending in the machine
direction, as well as a traction device for the tail of the web
that is arranged to move along and in relation to the guide, said
traction device comprising a drive wheel connected to the power
transmission of the traction device itself, said drive wheel being
arranged to transfer the traction device in relation to the guide
by means of a power transmitting contact between the guide and the
drive wheel, and wherein the drive wheel is arranged in a friction
contact with a friction contact plane of the guide and the friction
contact plane of the guide curves in directions perpendicular
thereto in accordance with the travel path of the paper web.
53. The apparatus of claim 52 wherein the guide comprises an
elongated profile having an outer surface which the drive wheel
contacts.
54. The apparatus of claim 53 wherein the elongated profile
comprises a flat bar.
55. The apparatus according to claim 53, wherein the traction
device comprises counter wheels positioned against the surface of
the profile on an opposite side of the profile with respect to one
or several drive wheels.
56. The apparatus of claim 55 wherein one or several drive wheels
and the counter wheels are connected to different frame parts
attached together to move with respect to each other in a direction
perpendicular to the friction contact plane of the guide.
57. The apparatus of claim 52 wherein the traction device contains
two or several successively coupled carriages that are articulated
to turn with respect to each other on the plane of curvature of the
guide, and in which the drive wheel or drive wheels and a fastening
point of the tail of the web or the auxiliary member are located in
different carriages.
58. The apparatus of claim 52, wherein the traction device
comprises three or several successively coupled carriages that are
articulated to turn with respect to each other on the plane of
curvature of the guide, and in which at least a power source is
positioned in a carriage of its own.
59. The apparatus of claim 57 wherein the power source comprises a
battery.
60. The apparatus of claim 52, wherein a belt is passed around at
least one drive wheel, said belt forming a loop that is arranged in
a friction contact with the guide.
61. The apparatus of claim 52 wherein the traction device comprises
a drive motor which is an electrical motor.
62. The apparatus of claim 52 wherein the speed of rotation of the
drive wheel of the traction device is adjustable.
63. The apparatus of claim 62 wherein the speed of rotation of the
drive wheel of the traction device is adjustable in a stepless
manner.
64. The apparatus of claim 62, wherein the speed of rotation of the
drive wheel of the traction device is adjustable by remote
control.
65. The apparatus of claim 52 wherein the traction device comprises
a power measurement sensor in a fastening point of the tail of the
web or the auxiliary member.
66. The apparatus of claim 52 wherein the guide comprises a channel
for a cooling medium.
67. An apparatus for tail threading of a paper web in a finishing
machine for paper, in which the paper web is arranged to travel
along a predetermined path, the apparatus comprising: a guide which
extends in a machine direction, and which has a friction contact
plane, the guide extending along a curved path which curves in both
directions in a direction perpendicular to its plane in accordance
with the windings of the path; a traction device comprised of a
plurality of carriages, which are arranged to move along and in
relation to the guide, wherein a first one of said plurality of
carriages comprises a drive wheel connected to a power transmission
of the traction device, the drive wheel being arranged to transfer
the traction device in relation to the guide by means of a power
transmitting contact between the guide and the drive wheel, wherein
the drive wheel is arranged in a friction contact with the friction
contact plane of the guide, wherein the friction contact plane of
the guide curves in directions perpendicular thereto in accordance
with the travel path of the paper web; and wherein a tail of the
paper web or an auxiliary member for threading the tail of the
paper web is connected to one of said plurality of carriages.
Description
[0001] The invention relates to a method for tail threading of a
paper web in a finishing machine for paper that is arranged to
guide a paper web along a predetermined path, wherein in the method
the tail of the web or an auxiliary member for tail threading of
the web are drawn by means of a traction device comprising power
transmission means of its own that transmit the traction device in
relation to a guide extending in the machine direction. The
invention also relates to an apparatus for tail threading of a
paper web in a finishing machine for paper, comprising a threading
device that is arranged to guide the tail of the paper web along a
predetermined path.
[0002] In the finishing machine of paper, which in this invention
includes for example a coating machine, a calender, a slitter
winder, a rereeler, a laminating machine and a printing machine,
the threading of the paper web takes place at a speed lower than
the actual running speed of the machine. Lower speed can be
utilized when starting to feed the paper web again from a new reel
through the finishing machine. When the paper web has been passed
through the machine at a low threading speed, it is possible to
accelerate the machine to the actual running speed (production
speed). The tail of the paper web refers at this stage to such a
paper web that is passed through the finishing machine before the
machine is accelerated to the full running speed, irrespective of
the production width of the web that may vary.
[0003] For example in a coating machine the web travels from an
unwinder to a reel-up under the guidance of many rolls via coating
stations and drying sections. In such machines the travel path of
the web typically contains a large number of upward and downward
directed sections and the path can be very winding. An example of
such path geometry is for example the EP patent 611716 that
discloses a machine comprising two coating stations to coat the
paper web on both sides.
[0004] The threading devices are for example belts or ropes that
guide for example a narrower lead-in strip separated from a
full-width web through the machine. At a suitable stage the lead-in
strip is spread into a full-width web by means of diagonal cutting.
In complicated transfers the threading ropes or belts require
several rope pulleys, belt guiding wheels or the like, as well as a
return circulation for the belts or ropes. The threading ropes or
belts require a traction device and a tightener to maintain
suitable tension. The traction device, the tightener and the return
section of the ropes/belts occupy a great deal of space in the
basement. Furthermore, during threading the belts or ropes move
within their entire length, which increases the possibility of
malfunctions.
[0005] U.S. Pat. No. 4,883,209 suggests as a threading device for a
treatment device of a paper web comprising complicated threading
processes an elongated fillet travelling next to the web and
comprising a hose in which pressurized medium is supplied. When the
hose expands, it moves a carriage in front of itself, the tail of
the web being attached to said carriage with a rope. A problem in
such an apparatus is that it is not possible to determine the
threading speed precisely. The apparatus requires a long actuator
(hose) extending on the entire length, which constitutes a factor
of uncertainty in the function of the threading apparatus, and it
is difficult to perform long threadings of tens of metres by means
of the apparatus.
[0006] The U.S. Pat. No. 3,761,001 discloses a carriage intended
for threading that travels along a rail in a printing machine. The
carriage is electrically operated and it may contain a battery. The
rail comprises a toothed bar equipped with cogged wheels to guide
the carriage and to accomplish a draw. The rail contains branching
sections and crossing sections for transferring the carriage as
well as the tail of the web via alternative routes through
different printing sections. There may also be two carriages
connected one after the other.
[0007] In the method according to the U.S. Pat. No. 3,761,001 the
tail of the web is thus drawn by means of a traction device
comprising a power transmission member of its own that transmits
the traction device in the direction of a guide extending in the
machine direction. In the US patent this is implemented in such a
manner that power is transmitted by means of a power transmission
mechanism from the battery to a cogged wheel that is in contact
with a cogging extending in the longitudinal direction of the
guide. Especially in FIGS. 7 to 9 of the patent it can be seen that
to implement the alternative routes shown in FIG. 1, the guides
curve in the direction of the plane of the cogging. This
complicates the travel of the carriage in threadings in which the
path contains steep, frequently occurring curves. It is a problem
of the cogging that impurities originating from the process, for
example paper strips or coating paste may accumulate between the
teeth and hamper the function of the guide.
[0008] It is an aim of the invention to present a method that does
not contain the above-identified problems. To implement this, the
method is characterized by the features presented in the
claims.
[0009] In the invention a traction device is moved along a guide
with one or several drive wheels that produce a movement in
relation to the guide by means of friction contact. The guide
curves in a direction perpendicular to the plane of the friction
contact in accordance with the winding of the path. The friction
contact surface does not require coggings or other corresponding
shapings, but it may be a straight surface. Advantageously, the
friction contact surface of the guide is straight in the
cross-section perpendicular to the longitudinal direction of the
guide, ending on both ends with a rectangular edge.
[0010] According to a preferred embodiment, the pressing force of
one or several drive wheels is attained by means of counter wheels
affecting from the opposite side of the cutting contact plane.
[0011] According to yet another embodiment, the friction contact is
attained by means of a belt or the like passed around at least one
drive wheel and one or several other wheels.
[0012] According to a preferred embodiment used especially in
coating machines, the transfer rate of the hold point of the
finishing machine and the speed of the traction device are adjusted
with respect to each other in such a manner that the end of the web
drawn by means of the traction device travels substantially at the
transfer rate of the hold point. When the finishing machine
operates at the threading speed that is clearly lower than the
normal running speed, it is possible to utilize the hold points in
the threading. For example when the end of the web in the form of a
narrow lead-in strip reaches the first such a hold point by which
it is possible to exert a tractive force on the tail of the web, it
is possible to start drawing the section of the tail of the web
preceding the hold point by means of the hold point at the same
time when the traction device continues the threading of the tail
of the web from the hold point onward. In the threading section
preceding the hold point it is thus possible to spread the web into
a wider one, for example into full width.
[0013] It is also possible to first draw a special auxiliary rope
on the entire threading path by means of the traction device and to
attach the rope thereafter from the traction device to a separate,
for example stationary traction device by means of which the tail
of the web attached to the rope is drawn on the threading path.
[0014] The guide travelling in the machine direction may extend on
the entire threading path on the tending side, complying with the
travel path of the web. The reliability of the threading process
can be ensured, because a constant force can be more accurately
adjusted in the lead-in strip drawn by the traction device or in
the auxiliary rope by means of which the entire web is drawn.
[0015] Another aim of the invention is to introduce a threading
apparatus located in the finishing machine for paper web that is
less complex than the threading ropes and belts of prior art. To
attain this purpose, the threading device is primarily
characterized in that the drive wheel is arranged in a friction
contact with the friction contact plane of the guide, and the
friction contact plane of the guide curves in directions
perpendicular thereto in accordance with the travel path of the
paper web.
[0016] The traction device is advantageously a carriage comprising
power transmission means of its own for moving the carriage along
the guide. The source of power of the carriage is advantageously
electricity. The electric power source is advantageously a battery
that travels along with the carriage. To adjust the threading speed
accurately to other conditions, especially to the threading speed
of the finishing machine, the speed of the carriage can be
adjusted, advantageously in a stepless manner. The speed adjustment
is preferably implemented by means remote control, wherein it is
possible to change the speed during the movement of the
carriage.
[0017] According to a preferred embodiment, the traction device
contains several carriages connected one after the other and having
separate functions. The carriages are connected in such a manner
that they turn in the plane of curvature of the guide so that the
device can comply with the curves of the guide, both with the outer
and inner curves. The carriages have different functions so that
one carriage functions as a driving carriage and the others
comprise power sources (batteries), control electronics and
transmitter/receiver functions.
[0018] The guide extending in the machine direction has a simple
structure in that respect that the only part moving during the
threading is the traction device, and long continuous functional
parts (ropes, belts, hoses) are not necessary. Furthermore, a
return circulation of the belt or rope is not required, but the
guide comprises an initial end and a final end between which the
traction device can travel back and forth from the initial end to
the final end during threading, and during the return movement from
the final end to the initial end to a new initial position of the
threading. Alternatively, the carriage can be detached from the
guide at the final end and carried separately to the leading end to
wait for a new threading. It is also possible to arrange a return
guide in the apparatus that does not follow the threading path, but
is intended to return the threading device to the opposite
direction in the starting point of threading. The cross-section of
the guide for the parts guiding the traction device can be very
simple, i.e. the friction contact plane can be straight in the
plane perpendicular to the longitudinal direction of the guide, and
on both edges on the other side of the same there may be contact
planes parallel thereto for the counter wheels of the traction
device.
[0019] The guide may be provided with straight sections and curved
sections in accordance with the path geometry. Furthermore, it is
possible to provide the guide, at least for a part of its length,
with a flow of cooling medium at least for the sections that are
located by the hot processing means of the finishing machine, for
example by the calender rolls.
[0020] In the following, the invention will be described in more
detail with reference to the appended drawings, in which
[0021] FIG. 1 shows a threading device according to the invention
at different stages in a side-view at the location of the rolls of
the finishing machine,
[0022] FIG. 2 shows a traction device and a guide in a
cross-sectional view on a plane perpendicular to the longitudinal
direction of the guide,
[0023] FIG. 3 shows a tractive carriage of the traction device and
the guide in a perspective view,
[0024] FIG. 4 shows the entire traction device in a side view on
the straight section of the guide,
[0025] FIG. 5 shows a side view of the traction device in a
curve,
[0026] FIG. 6 shows a side-view of a coater in which the threading
apparatus can be used,
[0027] FIG. 7 shows in perspective the function of the threading
device at the separation point of the lead-in strip,
[0028] FIG. 8 shows in perspective the function of the threading
device at the hold point of the coater,
[0029] FIG. 9 shows a traction device according to a second
embodiment in a side-view in the inner curve,
[0030] FIG. 10 shows the traction device of FIG. 9 in the outer
curve,
[0031] FIG. 11 illustrates the operating principle of the traction
device a of FIGS. 9 and 10, and
[0032] FIG. 12 shows a traction device according to a third
embodiment of the invention in a principle view.
[0033] In the following, the operating principle of the traction
device will be described. FIG. 1 shows a threading apparatus
travelling by a roll 5 in a finishing machine for paper, said
apparatus comprising a guide 1 whose cross-section will be
described in more detail hereinbelow, and a traction device 2
arranged movable in the guide and comprising supports or the like
for keeping the traction device in contact with the guide and
guiding it along the guide. The movement of the traction device
along the guide 1 is attained by means of one or several drive
wheels that are in a power transmitting connection with the guide 1
and obtain their driving force from power sources described
hereinbelow. The drive wheel is arranged to rotate on bearings in
the traction device, and it is in a power transmitting contact with
the guide by means of friction. Power transmission means connect
the drive wheel to a drive motor moving along with the traction
device. The power transmission may be for example a reduction gear.
The drive motor 4 is an electrical motor that receives its driving
force from a battery arranged to move along with the traction
device.
[0034] To the traction device 2 a lead-in strip is attached either
directly or by means of an elongated auxiliary member 6
transmitting tensile stress, such as an auxiliary rope, to which
the leading tail of the paper web can be attached. The traction
device can be equipped both with a fastening point for the
auxiliary rope and with fastening means of the narrower lead-in
strip separated from the paper web to fasten the web directly to
the traction device. The scope of the invention also covers the
idea according to which the traction device 2 is only utilized for
pulling the auxiliary member, which during the movement of the
traction device is not in a tensile stress transmitting contact
with the web, and it is not until the auxiliary member is pulled
with a device independent from the traction device, for example
with a stationary winder that the actual tail of the web is pulled
on the threading path.
[0035] FIG. 1 shows a situation in which the traction device
travels on the guide 1 on the side of the inner curve, i.e. on the
roll 5 side of the guide. The future travel path of the paper web
along which the paper web is arranged to travel by means of the
threading device is marked with the letter W. The fastening between
the traction device and the guide is arranged such that the
traction device complies well with the winding of the guide, being
sometimes in the inner curve, i.e. on the side of the centre of
curvature, and sometimes in the inner curve, i.e. on the opposite
side of the guide in relation to the centre of curvature. The drive
wheels of the traction device 2 are in a constant power
transmitting friction contact with the guide 1 in the straight and
curved sections. The plane of the guide along which the drive
wheels roll extends in an elongated shape with a predetermined
width in the machine direction and its width direction coincides
approximately with the cross-machine direction.
[0036] The guide 1 can be positioned on the entire length of the
finishing machine, for example on the tending side to a location in
which threading ropes or belts have been used previously. The guide
extends on the side of the future travel path of the paper web, and
a lead-in strip or an auxiliary means directed backwards therefrom
extends diagonally towards the middle. The straight sections of the
guide are located in points where the travel path of the web is
nearly straight, and there may be curved sections by the different
rolls and cylinders and air turning devices and by other devices
that change the direction of the paper web.
[0037] In the following, the structure of the guide 1 and the
traction device 2 will be described in more detail
[0038] FIG. 2 shows a cross-section of the guide 1 and the tractive
carriage 21 of the traction device 2. The guide is preferably an
elongated rail made of metal that has a predetermined profile shape
(standard cross-section). The primarily guiding section of the
guide is a flat bar 1a extending in the machine direction and
curving in both directions in a direction perpendicular to its
plane in accordance with the windings of the path. When necessary,
it is possible to strengthen the flat bar at suitable locations on
the side opposite to the friction contact side of the carriage by
means of a stiffening structure in suitable sections. The figure
shows a stiffening profile 1b extending in the longitudinal
direction of the guide, said stiffening profile forming a closed
pipe with the flat bar 1a, whereby a channel 1c is formed inside
the pipe and cooling medium, such as water, can be supplied
therein. The profile is dimensioned in such a manner that both
edges of the flat bar 1a remain free within a distance of
predetermined length in the width direction. The guide is
preferably prefabricated in such a manner that it can be assembled
by fastening elements of predetermined length abuttingly
together.
[0039] The tractive carriage 21 is connected to the guide against
the flat bar 1a by means of wheels positioned on the opposite sides
of its plane. The tractive carriage comprises drive wheels 3
positioned above the flat bar, said wheels transferring the
carriage while rotating by means of friction drive when they are in
a sufficiently strong contact with the upper surface of the flat
bar. On the lower side of the flat bar, close to both edges there
are counter wheels 4a, one before the contact point of the drive
wheel and the other after the contact point, said counter wheels,
when positioned in contact with the lower surface of the flat bar,
lock the carriage 21 to the guide 1. The terms upper surface and
upper side of the flat bar and the lower surface and lower side of
the flat bar refer to the different sides of the plane of the flat
bar, and the surface shown as an upper surface in the figure is not
necessarily always positioned upward.
[0040] The fastening point of the threading of the web is located
in the carriage 22 following the tractive carriage 21. As a result
of this the tractive carriage is only subjected to forces parallel
to the rail and centrifugal forces resulting from the curves of the
guide 1 that affect perpendicularly to the plane of the flat bar
1a.
[0041] The sideways locking of the tractive carriage 21 is attained
by means of control wheels 4b positioned against the edge of the
flat bar from the sides, said control wheels being also arranged
rotatable on bearings in the tractive carriage 21.
[0042] The tractive carriage 21 also comprises a drive motor M and
power transmission means for transmitting the rotation of the drive
motor with a suitable transmission ratio to the drive wheels 3.
FIG. 3 shows the tractive carriage 21 in perspective. The drive
motor M rotates a cogged wheel H1 located at the end of its shaft,
said cogged wheel transmitting the torque to a larger cogged wheel
H2 to whose shaft the drive wheels 3 are fastened. In the figure
there are two drive wheels next to each other, and they are
sufficiently wide to attain a good contact with the friction
contact surface of the guide (the upper surface of the flat
bar).
[0043] The drive motor M, the power transmission means (cogged
wheels) and the drive shaft of the drive wheels 3 are fastened to
the frame R1 of the carriage that is primarily composed of two
vertical frame plates located on both edges. The counter wheels 4a
and the control wheels 4b are arranged on bearings to rotate freely
in a second frame R2 composed of the outer frame plates, said frame
being arranged movable with respect to the first frame to set the
pressing force of the drive wheels 3. In the figure the frames are
articulated tumable with respect to each other.
[0044] As can be seen in the figure, there are two motors M, one in
front of the wheels (3) and one behind them, and they both rotate a
cogged wheel H1 of their own. The cogged wheels are in a torque
transmitting contact with the same main cogged wheel H2 on
different locations of its periphery.
[0045] Behind the tractive carriage 21 a fastening carriage 22 of
threading is attached as the next carriage, to which fastening
carriage it is possible to attach the end of a rope, belt or a
corresponding element that is in contact with the web. This
carriage contains freely rotating wheels 4a, 4b that are positioned
against the flat bar 1a from opposite sides on both edges of the
flat bar, two of said wheels being positioned successively in pairs
on both edges. The wheels 4a, 4b located on different sides of the
flat bar are connected to each other by means of a swinging arm
located outside the edge of the flat bar, said swinging arm being
capable of turning in such a manner that when the carriage is
pulled, the wheels are pressed against the flat bar 1a on opposite
sides. The fastening carriage 22 is subjected to a lateral force,
i.e. a force affecting in the direction of the plane of the flat
bar 1a that results from the tail of the web or the auxiliary
member of threading drawn behind. The fastening carriage comprises
a force measurement sensor arranged in the fastening point, by
means of which it is possible to constantly measure and monitor the
force used for drawing the tail of the web. The force information
can be transmitted to a control station wirelessly.
[0046] The force measurement sensor can also be arranged in the
threading means, for example in the middle of the auxiliary
tractive member producing tensile stress, such as a rope that is
attached from one end to the fastening carriage and from the other
to the web.
[0047] The fastening carriage is followed by a control electronics
carriage 23, a communication carriage 24 (reception of control
messages and transmission of measurement messages) and a battery
carriage 25 that are coupled successively to each other. Between
the carriages there are the necessary electrical couplings to
control the speed of the tractive carriage, to transmit signals
between the carriages and to supply driving force to the motor. As
can be seen in FIG. 4, the carriages following the tractive
carriage 21 comprise pairs of wheels 4a, 4b positioned against the
flat bar on opposite sides of the flat bar (on different sides of
the main plane of the flat bar). The wheels 4a, 4b located on
different sides of the flat bar can be connected with a rocking arm
that is articulated to the frame of the carriage. Some of the
wheels, for example the wheels 4b located on the upper surface of
the flat bar can be equipped with flanges, wherein their larger
diameter flanges ensure the lateral position of the carriage. The
carriages can also be connected successively in such a manner that
the shaft connecting some of the wheels transversely with respect
to the travel direction at the same time forms the joint for the
connection, wherein this pair of wheels is in a way shared by the
carriages.
[0048] By dividing the device drawing the web in the threading into
several carriages connected in the vertical plane in the machine
direction (in the plane of the guide perpendicular to the friction
contact plane of the flat bar) to turn in relation to each other,
the traction device can travel in curves having small radius, as
illustrated in FIG. 5, in which the traction device has bent in the
inner curve as a result of the articulations between the carriages.
The adjustment of the last carriages 24, 25 to the same small
turning radius at the location of the curve is illustrated by means
of the guide drawn with dotted lines.
[0049] FIGS. 4 and 5 illustrate primarily the chassis structures
and wheels of the carriages. It is obvious that the carriages can
be provided with different types of housings or covers to protect
the parts therein.
[0050] In view of the operation it is important that the rotating
speed of the drive wheels 3 can be adjusted and maintained constant
as accurately as possible and that the attained movement speed of
the carriage is directly and linearly proportional to this rotating
speed, and the travel direction in relation to the gravity (the
"ascents" and "descents" of the guide) has no affect thereon. The
contact of the drive wheels 3 to the guide 1 must be such that the
linear speed along the guide is dependent solely on the speed of
rotation of the drive wheels. The movement speed is adjusted by
adjusting the rotating speed of the drive motor by affecting its
electric input variable. The adjustment takes place advantageously
by means of remote control through the communication carriage 24 so
that the travel speed of the traction device can be rapidly
adjusted to the threading speed of the finishing machine, if
necessary.
[0051] In the following the threading in an off-coating machine or
off-calender will be described as an example. The traction device
is positioned on the guide 1 in the unwinder. A longitudinal
auxiliary member (hereinbelow auxiliary rope) or a lead-in strip is
fastened to the second carriage 22 of the traction device 2. If an
auxiliary rope is used, its other end is taped to the lead-in strip
or to a full-width paper web whose tail is pretreated in a suitable
manner, and the traction device pulls the lead-in strip or the
full-width paper web by means of the auxiliary rope. The web or the
lead-in strip is thus unwound from the paper reel located in the
unwinder. If a lead-in strip is used, it is cut in a known manner
from the full-width paper web by means of a cutting device, for
example by means of a diagonal cutting device, by means of which
the cutting point can be changed in the cross-machine direction,
and the rest of the web is directed to a broke processing system,
such as a pulper. The width of the lead-in strip is typically
approximately 100 to 300 mm. By means of such a diagonal cutting
device it is possible to spread a narrower lead-in strip into a
full-width web as the threading proceeds. It is also possible to
use a pre-cut lead-in strip that is unwound from a reel of its own
and seamed at a suitable stage to the actual web drawn through the
machine. The tail of the web (the lead-in strip or a full-width
web) is drawn by the carriage and guided by the guide through a
coating machine or calender at the normal threading speed
(typically 30 to 100 m/min). The traction device travels to the
reel-up drawing the tail of the web at the same time behind itself.
When the traction device arrives to the reel-up, the auxiliary rope
or lead-in strip is separated therefrom. The auxiliary rope of the
reel-up or the lead-in strip can be attached to a winder that
maintains the tension of the lead-in strip or the auxiliary rope.
By means of the winder it is possible to wind the lead-in strip
until the full-width web following thereafter enters into a
position in which it can be transferred to the reeling core.
[0052] It is also possible that when the auxiliary rope is used, it
is so long that the full-width web does not follow the threading
movement of the traction device, but the traction device is first
utilized to pass the auxiliary rope on the entire length of the
machine, and when the traction device is in the end of the guide,
the auxiliary rope and the web attached to its final end (possibly
only at this stage) is drawn on the travel path of the web on the
entire length of the machine by means of the winder. Such an
auxiliary rope may be of pulpable quality. Its tensile strength can
be arranged in such a manner that it is capable of drawing the web
through the finishing machine, but breaks in sudden tensile
stresses. Thus, risks in occupational safety are not caused if the
rope ends up in the vicinity of the rolls and cylinders of the
finishing machine that rotate at the running speed or are
accelerated to the running speed.
[0053] When the full-width web following the lead-in strip or the
auxiliary rope has been passed through the entire machine by
running the machine at the threading speed, the web is lifted up on
the reeling core of the reel-up and the entire machine is
accelerated to the actual running speed.
[0054] The traction device can be transferred from the reel-up
manually back to the initial position via the same guide via which
the threading was conducted. Alternatively, the carriage can be
released from the guide and transferred back in another way. There
may be several carriages, wherein the initial end always contains
one or several carriages ready.
[0055] According to one alternative, it is possible to equip the
apparatus with a special return guide along which the traction
device can travel back by means of its own operating force. The
return guide can be positioned below the finishing machine, for
example below the floor level.
[0056] FIG. 6 shows as an example a four-station coater that is
intended for coating the paper web on both sides. The principle is
that in such a machine the paper web is coated on both sides twice,
and after each coating station there is a drying section in the
travel direction of the web. The drying section contains
successively a contactless dryer in which the drying of the
recently coated web takes place on contactless principle, and a
drying cylinder group in which the web is dried on contact
principle. The figure illustrates how there may be several upward
and downward directed threadings and a large number of winding
sections in the machine, in which the path curves to opposite
directions, for example especially at the location of the drying
cylinder groups. In the coater shown in the figure, the first hold
point P is in the location in which the web enters the space
between the cylinder 7 of the first drying cylinder group R1 and
the drying wire 8 after the coating station C1. The first drying
cylinder group R1 is shown in a larger scale at the bottom of FIG.
6. In the travel direction of the web and in the direction of
propagation of the threading this hold point P is preceded by a
contactless dryer D1 through which the web is passed from above
from the coating station C1 to the drying cylinder group R1. Other
coating stations are marked with the references C2, C3 and C4, the
contactless dryer following each station correspondingly with the
references D2, D3 and D4, and the drying cylinder group following
each contactless dryer correspondingly with references R2, R3 and
R4. The unwinder at the initial end of the coating machine is
marked with the reference numeral 9 and the reel-up at the final
end with the reference numeral 11. Between the last drying cylinder
group R4 and the reel-up there is also a calender 10. The guide 1
travels through the entire coater from the unwinder 9 to the
reel-up 11 at least in such a manner that it travels via all
coating stations and the drying sections following thereafter. The
coating machine is not necessarily similar to the one described
above. It may contain fewer than four coating stations, for example
only two coating stations to coat the web on both sides.
[0057] In the coating machine the threading distance may be
significantly longer when compared to the length of the machine
measured on the floor level because of the complicated transfers in
which the web can start moving to the incoming direction at several
points. Thus, threading distances of over 100 meters measured along
the path are common, and in the four-station coating machine of
FIG. 3 the distance is over 200 meters. The drawing of the narrow
lead-in strip only with the traction device for distances over 100
meters is not reasonable because of the breaking risk. When a
traction device 2 travelling along a guide is used for drawing the
tail of the web, the steps illustrated in FIG. 8 are taken, in
other words, the tail of the web is transferred from the unwinder
to the first hold point P described above solely with the force of
the traction device 2, whereafter the transfer movement of the hold
point produces a traction between the unwinder and the hold point.
FIG. 8 shows how the guide 1 follows the winding travel of the web
and is located outside the peripheral surfaces of the cylinders of
the cylinder group R1 that are arranged rotatable on bearings, and
curves in accordance with the peripheral surfaces that guide the
web. The traction device 2 is located in the point in which it has
drawn the lead-in strip 12 between the peripheral surface of the
drying cylinder 7 and the drying wire 8. The traction device 2
travels at the speed of the coating machine, which in an
off-coating machine is typically 30 to 100 m/min during the
threading. Thus the lead-in strip 12 following thereafter travels
at the speed of the peripheral surface of the cylinder 7 and the
drying wire 8. The belt is attached to the traction device in the
drawing direction by means of an elastic auxiliary member 6, for
example a rubber band, so that small differences between the
surfaces of the traction device 2 and the surfaces of the machine
do not cause tension in the attachment between the traction device
2 and the lead-in strip 12. When the lead-in strip 12 remains
between the drying wire 8 and the cylinder 7, the drawing of the
lead-in strip shifts to the drying group. FIG. 8 shows a traction
device 2 composed of one carriage, and the power transmission and
the fastening point of the threading means are located in the same
carriage. Such an alternative also belongs within the scope of the
invention. In the situation of FIG. 8, it is possible to use a
traction device 2 with several carriages as well. The fastening
point of the elastic auxiliary member 6 can thus be located in the
carriage following the traction device.
[0058] As can be seen in FIG. 7, there is a point before the hold
point P in the travel direction of the lead-in strip 12, in which
point the lead-in strip 12 is separated from the full-width web W
by means of a cutting device 13, for example by means of a waterjet
cutter, and the remaining part is conveyed down to the pulper 14 or
to a corresponding broke processing system. The cutting device 13
is a diagonal cutter that is capable of moving in the
cross-direction of the web (arrow S), and to spread the strip 12
into a full-width web when moving from the tending side to the
operating side. The spreading takes place at a suitable stage,
preferably after the lead-in strip 12 is already drawn by the hold
point P. Thus, at least in the initial section of the machine it is
possible to start conveying a web wider than the lead-in strip 12,
although the traction device has not yet proceeded to the end of
the threading path.
[0059] The traction device 2 travels through the entire drying
cylinder group at the speed of the drying cylinders and the drying
wire. After the drying cylinder group the initial end of the
lead-in strip 12 is no longer guided by the drying cylinders and
the drying wire. The traction device 2 draws the initial end of the
lead-in strip 12 again to the next hold point in the free section
following the drying cylinder group.
[0060] The invention is not restricted solely to be used in the
above-identified coaters, but other off-machine processing
machines, such as calenders are also possible, in which a guide can
be used for guiding the tail of the web or the auxiliary member
preceding the tail through the calender nips.
[0061] FIG. 9 shows a traction device according to a second
embodiment in a side-view in the inner curve of the guide. The
guide 1 is shown as a full circle with the intention of
illustrating in how small a radius of curvature the traction device
2 is capable of moving. The first element in the traction device is
the motor carriage 20, from which the power transmission to the
tractive carriage 21 takes place by means of a belt transmission
located at the side. The tractive carriage 21 also contains the
necessary control electronics and the transmission and reception of
messages, i.e. it also comprises the functions of the control
electronics carriage and the communication carriage. This is
followed by a series of carriages connected successively, of which
carriages at least some carry the batteries necessary as power
sources for the motor carriage 20, i.e. they correspond to the
battery carriages 25 of the previous embodiment. It is possible
that some carriages do not contain batteries, wherein they function
only as intermediate carriages that connect two successive
carriages to each other. The last carriage in the travel direction
is the fastening carriage 22 of threading that may also contain
batteries. The end of the member connected to the web can be
attached to this carriage.
[0062] FIGS. 9 and 10 also show counter wheels 4a that enter in
contact with the guide from the opposite side, said counter wheels
functioning on the same principle as hereinabove, in other words
they ensure that the wheels of the carriages are pressed with a
sufficient force against the friction contact plane of the guide 1.
The counter wheels 4a are arranged at the ends of arms articulated
to turn in the plane of curvature of the guide. The pressing force
can be set by means of a spring 4c that is connected to the arm in
a power transmitting contact. At least some of the wheels of the
traction device contain side flanges that extend below the friction
contact plane of the guide, i.e. they guide the traction device
sideways in relation to the guide 1. FIGS. 9 and 10 also illustrate
how successive carriages share freely rotating wheels 4b in the
articulation points between the carriages.
[0063] FIG. 11 shows in a simplified manner the operating principle
of the traction device of FIGS. 9 and 10, when a traction device of
only three carriages is used as an example. A belt 3a is passed
around the drive wheel 3 of the tractive carriage, the belt being
actually in direct friction contact with the plane of the guide. On
the inner surface of the belt there is advantageously a cogging
that meshes with a corresponding cogging on the outer periphery of
the drive wheel 3. The belt is also passed around other freely
rotating wheels 4b in such a manner that it forms a closed loop and
is in contact with the wheels 4b also above, at the location of the
return section of the loop. Said belt 3a travels via the freely
rotating wheels 4b of all the succeeding carriages. At the location
of the last wheel 4b of the last carriage 22 there is a tightening
member 4c (FIGS. 9 and 10), such as a spring by means of which it
is possible to adjust the tension of the entire belt loop.
Furthermore, the carriages comprise auxiliary wheels 15 by means of
which it is possible to adjust the shape of the belt loop to the
outer curves and inner curves in such a manner that the belt does
not become excessively tightened or loosened. These auxiliary
wheels 15 are positioned against the belt in the return section of
the loop between the wheels 4b under the loading of the springs 4d
(FIGS. 9 and 10).
[0064] By means of the belt 3a it is possible to attain a contact
for a longer distance in the longitudinal direction of the guide 1,
and thus the tension remains even if there was oil or water on the
surface of the guide.
[0065] FIG. 12 shows schematically a third embodiment of the
invention. The carriages can be equipped with mere wheels or a belt
loop passed around the wheel, similarly to the solutions
hereinabove. It is a special feature herein that the tractive
carriage 21 of the traction device 21 is located after the
carriages 23, 25 containing the control electronics, the
transmission and reception functions and the power sources
(batteries) in the travel direction of the device, i.e. in the
direction of propagation of the threading, and it draws the
fastening carriage 22 of threading after itself. This illustrates
the fact that the traction carriage does not necessarily have to be
the first one of the several carriages of the traction device, but
it can push carriages comprising other functions in front of it,
the only prerequisite being that it transmits traction to the
threading member that can be connected directly to the traction
carriage or to a separate fastening carriage connected
thereafter.
[0066] The structure of the guide 1 can be arranged in the
appropriate manner, taking into account for example the conditions
of the finishing machine. In the area of the coating stations and
the calender, a guide is advantageously used, inside of which a
flow of cooling medium, for example water, is arranged, and here it
is possible to use a hollow profile formed on the other side of the
flat bar. The need for cooling can occur for example in the
vicinity of hot rolls of the calender, and in infra dryers and
flotation dryers. In coating stations the cooling medium is
advantageous in that respect that the outer surface of the guide
can be arranged to condensate, whereby it can be kept clean.
[0067] When a power source, such as a battery moving with the
traction device is utilized, it is possible to arrange a charger
for charging the batteries at a suitable location in the guide.
This charger can be located for example in the unwinder, and it can
be placed in such a manner with respect to the guide 1 that the
traction device can be charged without removing it from the
guide.
[0068] As was mentioned above, the returning of the traction device
to the initial end of threading in the threading apparatus can be a
return guide. The guide 1 can thus form a closed loop comprising a
threading section extending in the travel direction of the web, and
a return section extending in the opposite direction preferably
underneath, the final end of said return section possibly
comprising a charging station for charging batteries. Furthermore,
there may be several traction devices 2 in use, which wait for
their turn in the unwinder.
[0069] The loading station can also be located in the reel-up
before the beginning of the return section of the guide. Also in
this case there may be several traction devices 2 waiting for their
turn. Thus, a charging station is not necessary in the
unwinder.
[0070] The guide 1 may also comprise branches, i.e. alternative
travel paths that correspond to the alternative threading paths of
the finishing machine. Each of these points can be equipped with a
mechanical gear that guides the traction device to the correct
path.
[0071] Furthermore, it is possible to arrange the transmission of
operating power to the traction device 2 in other ways than by
means of an accompanying power source (battery). It is for example
possible to provide the guide with a power rail from which the
carriage can receive its driving power and transmit it to the power
transmission means with which the carriage moves along the guide.
However, when the operating environment is taken into account, a
guide with a simple structure and no power transmission is the most
reliable and safe solution.
* * * * *