U.S. patent application number 12/084520 was filed with the patent office on 2009-05-28 for method for avoiding ribbon windings.
This patent application is currently assigned to Oerlikon Textile GmbH & Co. KG. Invention is credited to Gregor Gebald, Manfred Lassmann, Jurgen Meyer, Maximilian Preutenborbeck, Olaf Reissig.
Application Number | 20090134263 12/084520 |
Document ID | / |
Family ID | 37635676 |
Filed Date | 2009-05-28 |
United States Patent
Application |
20090134263 |
Kind Code |
A1 |
Preutenborbeck; Maximilian ;
et al. |
May 28, 2009 |
Method for Avoiding Ribbon Windings
Abstract
A method for avoiding ribbon windings in producing cross-wound
bobbins at the workstations of textile machines in the "random
winding" type of winding, by changing the traversing speed at which
the thread is wound onto the bobbin. Each workstation has a single
motor drive activated for the rotation of the cross-wound bobbin,
and a single motor drive activated for a traversing thread guide.
The diameters (D.sub.SP k) of the bobbin (8) which are critical
with regarding to the development of ribbon windings depending on
the width (B.sub.Sp) of the bobbin (8) and a cross-winding angle
(.alpha.) are determined, and, shortly before reaching each
critical diameter (D.sub.SP k), the cross-winding angle (.alpha.)
is changed to a value (.alpha..sub.1), which avoids development of
ribbon windings in this diameter region, and the cross-winding
angle (.alpha..sub.1) is reset to its original value (.alpha.)
after the critical diameter (D.sub.SP k) has been passed.
Inventors: |
Preutenborbeck; Maximilian;
(Monchengladbach, DE) ; Meyer; Jurgen; (Aachen,
DE) ; Lassmann; Manfred; (Nettetal, DE) ;
Reissig; Olaf; (Dusseldorf, DE) ; Gebald; Gregor;
(Monchengladbach, DE) |
Correspondence
Address: |
K&L Gates LLP
214 N. TRYON STREET, HEARST TOWER, 47TH FLOOR
CHARLOTTE
NC
28202
US
|
Assignee: |
Oerlikon Textile GmbH & Co.
KG
Monchengladbach
DE
|
Family ID: |
37635676 |
Appl. No.: |
12/084520 |
Filed: |
November 7, 2006 |
PCT Filed: |
November 7, 2006 |
PCT NO: |
PCT/EP2006/010624 |
371 Date: |
May 2, 2008 |
Current U.S.
Class: |
242/477.6 |
Current CPC
Class: |
B65H 2701/31 20130101;
B65H 54/38 20130101 |
Class at
Publication: |
242/477.6 |
International
Class: |
B65H 54/38 20060101
B65H054/38; B65H 54/02 20060101 B65H054/02 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 15, 2005 |
DE |
10 2005 054 356.1 |
Claims
1. Method for avoiding ribbon windings in the production of take-up
bobbins which are wound at the workstations of textile machines
producing cross-wound bobbins in the "random winding" type of
winding, by changing the traversing speed at which the yarn is
wound onto the take-up bobbin, the workstations in each case having
a single motor drive, which can be activated in a defined manner
for the rotation of the cross-wound bobbin, and a single motor
drive which can be activated in a defined manner for a traversing
yarn guide, characterised in that the diameters (D.sub.SP k) of the
cross-wound bobbin (8) which are particularly critical with
regarding to the development of ribbon windings and depend on the
width (B.sub.Sp) of the cross-wound bobbin (8) and a cross-winding
angle (.alpha.) selected during the winding of the cross-wound
bobbin (8), are determined, in that, in each case, shortly before
reaching one of these critical diameters (D.sub.SP k), the
cross-winding angle (.alpha.) is changed to a value
(.alpha..sub.1), which rules out the development of ribbon windings
in this diameter region and in that the cross-winding angle
(.alpha..sub.1) is reset again to its original value (.alpha.)
after the critical diameter (D.sub.SP k) has been passed.
2. Method according to claim 1, characterised in that the critical
diameters (D.sub.SP k) of the cross-wound bobbin (8) are determined
according to the formula (D.sub.SP k)=(whole number) x bobbin width
(B.sub.Sp)/.pi..times.tan of half the cross-winding angle
(.alpha./2).
3. Method according to claim 1, characterised in that the
cross-winding angle (.alpha.) is reduced shortly before reaching a
critical diameter (D.sub.SP k) of the cross-wound bobbin (8).
4. Method according to claim 1, characterised in that to change the
cross-winding angle (.alpha.), the speed (V.sub.FF) of the
traversing yarn guide (18) is changed, the rotational speed
(V.sub.WW) of the winding roller (19) being simultaneously adjusted
in such a way that the yarn tension of the running-on yarn (7)
remains virtually constant.
5. Method according to claim 4, characterised in that a stepping
motor (20) is used as the drive for the traversing yarn guide (18).
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application claims the benefit of German patent
application 10 2005 054 356.1, filed Nov. 15, 2005, herein
incorporated by reference.]
BACKGROUND OF THE INVENTION
[0002] The invention relates to a method for avoiding ribbon
windings during the production of take-up bobbins Method for
avoiding ribbon windings in the production of take-up bobbins which
are wound at the workstations of textile machines producing
cross-wound bobbins in the "random winding" type of winding, by
changing the traversing speed at which the thread is wound onto the
take-up bobbin, the workstations in each case having a single motor
drive, which can be activated in a defined manner for the rotation
of the cross-wound bobbin, and a single motor drive which can be
activated in a defined manner for a traversing thread guide.
[0003] During the production of take-up bobbins at workstations of
textile machines producing cross-wound bobbins, a thread which is
manufactured in an open-end spinning device, for example, and
supplied at a virtually constant speed to a winding device when
running onto a bobbin is displaced by a traversing thread guide in
such a way that it runs in crossing layers onto the bobbin and thus
forms a so-called cross-wound bobbin. During the production of
cross-wound bobbins in the "random winding" type of winding, there
is, however, the problem that if no particular measures are taken,
so-called ribbon windings repeatedly occur in the course of the
bobbin travel. Such ribbon windings always occur if a whole-number
winding ratio is present, in other words, if the cross-wound bobbin
carries out one or more complete revolutions per double stroke of
the traversing thread guide. In a case such as this, the reversal
points of the thread are substantially located over the reversal
points of the previous stroke, so the thread is repeatedly placed
on the same or a directly adjacent point on the winding periphery
which leads to ribbon-like thread layers which are designated
ribbon windings.
[0004] As the stripping-off of complete yarn layers from the bobbin
surface often occurs when there is such a non-homogeneous structure
of the yarn layers when unwinding the cross-wound bobbins, and this
leads to serious operating disruptions, ribbon windings of this
type absolutely have to be avoided.
[0005] Various methods and devices which are to be used during the
bobbin build-up to overcome the aforementioned problems have
therefore been known for a long time to avoid ribbon windings. With
these so-called ribbon disrupting methods and mechanisms, the
winding ratio is influenced in the regions of the cross-wound
bobbin at risk of ribbon winding.
[0006] DE 25 34 239 C2, for example, describes a device and a
method for ribbon disruption, in which it is attempted, by means of
constant changing of the cross-winding angle, to prevent the
development of whole-number winding ratios. The traversing thread
guides of one machine side can be driven here together by a first
drive at least two different speeds and the winding rollers of this
machine side can be driven together by a second drive. The two
drives are also connected to one another by an electronic gearing
in such a way that the winding rollers and therefore the
cross-wound bobbins are driven in such a way, synchronously and as
a function of the movement of the traversing thread guides, that
the quotient of the rotational speed of the cross-wound bobbins and
the cosine of half the thread cross-winding angle is constant.
[0007] In other words, in this known method, an attempt is made
both to avoid whole-number winding ratios and also to keep the
resulting winding speed of the thread and therefore the thread
tension virtually constant.
[0008] A ribbon disruption method is also known from DE 43 37 891
A1, in which a thread supplied at a constant speed and wound onto a
cross-wound bobbin in the "random winding" type of winding is wound
on at a changeable traversing speed to avoid ribbon windings. The
mechanism has a single motor driven winding roller and a single
motor driven traversing thread guide. In this known ribbon
disrupting method, the traversing speed of the thread guide is
subjected to a non-periodic change. The maximum and minimum values
of the traversing speed, at which in each case a changeover takes
place from an acceleration to a deceleration and vice versa, and
the time intervals between the reversal points, are changed in this
case by means of a computer within predetermined limits.
[0009] A ribbon disrupting method is furthermore known from DE 196
28 402 A1, in which, similarly to in the mechanism according to DE
25 34 239 C2, the winding rollers of one machine side are driven
together by a first drive and the thread guides of this machine
side are driven together by a further drive.
[0010] The traversing speed of the thread guides and the rotational
speed of the winding rollers are constantly changed here in
opposite directions between predetermined top and bottom values
around an average value.
[0011] One of the two speeds in this case forms the reference
variable which the other speed is made to follow as a following
variable of the method. In each case, if the reference variable has
reached a top or bottom value, at the beginning of its change in
the opposite direction a signal is generated which triggers the
change of the following variable in the opposite direction.
[0012] A ribbon disrupting method for cross-wound bobbins, which
are wound in the "random winding" type of winding, is also
described in DE 102 09 851 A1. In this known method, as a function
of the delivery speed of the thread, the degree of tensioning
drawing and the cross-winding angle, the rotational speed of the
winding roller is fixed and the cross-winding angle is changed by
changing the speed of the traversing thread guide for the purpose
of ribbon disruption. The drive for the winding rollers and the
drive for the traversing thread guides are configured as
speed-controllable motors, to which a signal representing the value
of the desired cross-winding angle is supplied, from which the
motors derive the required motor speed.
[0013] The aforementioned ribbon disrupting methods or ribbon
disrupting mechanisms have the disadvantage, however, that they are
all relatively complicated or expensive.
[0014] In other words, to carry out the known methods, either a
high mechanical and control outlay is required or the ribbon
disrupting methods lead to unsatisfactory results during the
winding of the cross-wound bobbins.
SUMMARY OF THE INVENTION
[0015] Proceeding from the aforementioned prior art, the invention
is based on the object of providing a relatively simple method for
avoiding ribbon windings, which method is advantageous to use in
particular in workstations, which have single motor drives for the
winding rollers and the traversing thread guide.
[0016] This object is achieved according to the invention by a
method as described in claim 1. Method for avoiding ribbon windings
in the production of take-up bobbins which are wound at the
workstations of textile machines producing cross-wound bobbins in
the "random winding" type of winding, by changing the traversing
speed at which the thread is wound onto the take-up bobbin, the
workstations in each case having a single motor drive, which can be
activated in a defined manner for the rotation of the cross-wound
bobbin, and a single motor drive which can be activated in a
defined manner for a traversing thread guide, characterised in that
the diameters (D.sub.SP k) of the cross-wound bobbin (8) which are
particularly critical with regarding to the development of ribbon
windings and depend on the width (B.sub.Sp) of the cross-wound
bobbin (8) and a cross-winding angle (.alpha.) selected during the
winding of the cross-wound bobbin (8), are determined, in that, in
each case, shortly before reaching one of these critical diameters
(D.sub.SP k), the cross-winding angle (.alpha.) is changed to a
value (.alpha..sub.1), which rules out the development of ribbon
windings in this diameter region and in that the cross-winding
angle (.alpha..sub.1) is reset again to its original value
(.alpha.) after the critical diameter (D.sub.SP k) has been
passed.
[0017] Advantageous configurations of the invention are the subject
of the sub-claims.
[0018] The method according to the invention offers the possibility
of reliably preventing right from the start the production of
ribbon windings in that suitable measures are already taken to
disrupt ribbons before a critical region is reached during the
winding of a cross-wound bobbin. In other words, shortly before
reaching a critical region of this type predetermined by the bobbin
width and the cross-winding angle, the winding ratio is adjusted in
a defined manner by changing the cross-winding angle in such a way
that the production of ribbon windings are reliably ruled out. The
changed cross-winding angle is retained here until the critical
diameter region of the cross-wound bobbin has been passed. The
original cross-winding angle is then reset and winding continues
with this cross-winding angle until in the course of the bobbin
travel, the diameter of the cross-wound bobbin approaches the next
critical diameter region.
[0019] As shown in claim 2, the critical diameter regions of a
cross-wound bobbin wound by the "random winding" type of winding is
advantageously calculated by the formula: D.sub.SP
k=A.times.B.sub.SP/.pi..times.tan(.alpha./2), wherein D.sub.SP k
stands for a critical diameter region of the cross-wound bobbin, A
stands for a whole number, B.sub.SP stands for the respective
bobbin width of the cross-wound bobbin and a stands for the
selected cross-winding angle of the cross-wound bobbin. The
diameter data can be calculated, for example, in a workstation
computer and processed such that before a critical diameter region
of the cross-wound bobbin is reached, a change in the cross-winding
angle is in each case initiated in a timely manner. The regions of
the cross-wound bobbin are called a critical diameter region, in
which a whole-number winding ratio is present, in other words, in
which the cross-wound bobbin carries out one or more complete
revolutions per double stroke of the traversing thread guide
because of the present diameter.
[0020] As described in claim 3, it is provided, in this case, in an
advantageous embodiment that the cross-winding angle is reduced
shortly before reaching a critical cross-wound bobbin diameter, by
reducing the speed of the traversing thread guide.
[0021] The reduction in the cross-winding angle leads directly to a
change in the winding ratio with the result that ribbon windings
cannot occur in this per se critical diameter region of the
cross-wound bobbin.
[0022] As shown in claim 4, to change the cross-winding angle, the
workstation computer preferably initiates a speed change of the
traversing thread guide. At the same time, the rotational speed of
the winding roller and therefore the winding speed of the
cross-wound bobbin are also adjusted in such a way that the thread
tension of the running-on threads remains virtually constant. In
other words, the speeds of the traversing thread guide and winding
roller are adjusted in such a way that the resultant force of the
displacement speed of the traversing thread guide and the
rotational speed of the winding roller constantly remain virtually
the same.
[0023] According to claim 5, the drive of the traversing thread
guide is preferably configured as a stepping motor. Such stepping
motors are economical mass produced components, which can also be
very precisely activated in a relatively simple manner. In other
words, very precise displacement of the traversing thread guide is
possible, for example, with such stepping motors, the outlay for
control being kept within reasonable limits.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The invention described in more detail below with the aid of
an embodiment shown in the drawings, in which:
[0025] FIG. 1 shows a side view of a workstation of an open-end
rotor spinning machine producing cross-wound bobbins, with a
winding device which operates by the method according to the
invention,
[0026] FIG. 2 schematically shows, to an enlarged scale, the
winding device required to carry out the method according to the
invention,
[0027] FIG. 3 shows a graph, which makes clear the connection
between the rotational speed of the winding roller and the speed of
the traversing thread guide, in particular when there is a change
in the cross-winding angle,
[0028] FIG. 4 schematically shows the thread run in a cross-wound
bobbin, which has reached a critical diameter region.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] FIG. 1 schematically shows a side view of one half of a
textile machine 1 producing cross-wound bobbins, in the embodiment
of an open-end rotor spinning machine. Textile machines of this
type, as known, have between their end frames (not shown) a large
number of similar workstations 2, which inter alia have a spinning
unit 3, in each case, as well as a winding device 4. Fibre bands 6,
which are stored in spinning cans 5, are processed to form threads
7 in spinning units 3, which threads are then wound on the winding
devices 4 to form cross-wound bobbins. The finished cross-wound
bobbins 8 are conveyed, for example, by means of a cross-wound
bobbin transporting mechanism 12 to a loading station (not shown)
arranged at the end of the machine.
[0030] As also indicated in FIG. 1, the individual workstations 2,
apart from the spinning unit 3 and the winding device 4, also have
further handling mechanism, for example a thread take-off mechanism
10, a suction nozzle 17 or a waxing device 14. The functions of
these components are known and described in detail in numerous
patents.
[0031] The winding device 4 substantially has a creel 9, a winding
roller 11 as well as a thread traversing mechanism 16. The winding
roller 11, which can be driven by a single motor by means of a
drive 13, in this case drives the cross-wound bobbin 8, which is
freely mounted in the creel 9, by frictional engagement.
[0032] FIG. 2 schematically shows a front view of a winding device
4 required to carry out the method according to the invention.
[0033] As indicated in the drawing, the cross-wound bobbin 8 freely
rotatably held in a creel (not shown) rests on a winding roller 11
and is entrained thereby by frictional engagement.
[0034] The winding roller 11 is in this case connected to a drive
13, which is in turn connected via a control line 23 to a
workstation computer 19. To displace the thread 7 while running
onto the bobbin 8, a thread traversing mechanism 16 is also
provided, the traversing thread guide 18 of which is driven in an
oscillating manner by its own drive, preferably a stepping motor
20. The stepping motor 20 is also connected to the workstation
computer 19 via a control line 24 and can be activated thereby in a
defined manner.
[0035] Furthermore, a sensor mechanism 21 is provided, which is
connected via a signal line 22 to the workstation computer 19 and
detects the respective rotational speed of the cross-wound bobbin 8
during the winding process. In other words, the workstation
computer 19 is supplied with signals of the sensor mechanism 21
and, using the rotational speed of the winding roller, the known
diameter of the winding roller and the rotational speed of the
cross-wound bobbin 8 determined by the sensor mechanism 21
constantly calculates the instantaneous diameter of the cross-wound
bobbin 8.
[0036] FIG. 3 shows a graph, in which the speed V.sub.FF of the
traversing thread guide 18 is shown on the abscissa and the
rotational speed V.sub.WW of the winding roller 11 is shown on the
ordinate. As indicated, a thread take-up speed V.sub.A1 is produced
during the regular bobbin travel at a speed V.sub.1 FF of the
thread guide 18 and a rotational speed V.sub.1 WW of the winding
roller 11. In this case, the thread runs onto the cross-wound
bobbin 8 at an angle .alpha./2.
[0037] Shortly before reaching a critical diameter region D.sub.SP
k of the cross-wound bobbin 8, the value of the thread run-on angle
.alpha./2 is changed to .alpha..sub.1/2. In other words, the speed
of the thread guide 18 is reduced to V.sub.2 FF, as shown in FIG.
3. In order to keep the thread take-up speed V.sub.A1=V.sub.A2
constant, the rotational speed of the winding roller 11 is also
adjusted in such a way that the winding roller 11 now rotates at
V.sub.2 WW. This means that the resulting thread take-up speed
V.sub.A1 or V.sub.A2 being produced from the rotational speed
V.sub.WW of the winding roller 11 and the speed V.sub.FF Of the
thread guide 18 remains constant regardless of the thread
cross-winding angle .alpha. or .alpha..sub.1.
[0038] FIG. 4 shows a cross-wound bobbin 8, which has reached a
first critical diameter region D.sub.SP k depending on the bobbin
width B.sub.SP and the cross-winding angle .alpha.. As indicated
with the aid of the line 30 representing the thread run, or the
associated arrows 31 to 36, a plurality of complete revolutions of
the cross-wound bobbin 8 would take place at this diameter of the
cross-wound bobbin 8 and a cross-winding angle .alpha. per double
stroke of the traversing thread guide 18, with the result that the
thread would be placed in thread deposits located one above the
other.
[0039] In order to avoid ribbon windings, the value of the
cross-winding angle .alpha. is changed to .alpha..sub.1 shortly
before reaching the critical diameter region D.sub.SP k. At a
cross-winding angle .alpha..sub.1 and a bobbin width B.sub.SP, it
is ensured, in the region of the cross-wound bobbin diameter
D.sub.SP k that no ribbon windings can occur.
[0040] The thread run being adjusted at a cross-winding angle
.alpha..sub.1 and a bobbin width B.sub.SP is indicated in FIG. 4
with the aid of the line 40 or the associated arrows 41 to 49.
[0041] Functioning of the method according to the invention:
At the beginning of a batch, firstly the most important parameters
of the cross-wound bobbin, for example the provided final diameter
of the cross-wound bobbin 8, the bobbin width B.sub.SP, the
cross-winding angle .alpha., with which the cross-wound bobbin 8 is
to be wound, as well as a further cross-winding angle .alpha..sub.1
are established and input for example into the central control unit
of a textile machine.
[0042] The central control unit of a textile machine is, in this
case, in turn connected to the individual workstation computers 19
of the workstations 2 preferably via a bus connection or the like.
The central control unit or the workstation computers 19 firstly
calculates/calculate, with the aid of the aforementioned data, the
critical diameter regions D.sub.SP k of the cross-wound bobbin, in
other words, the regions in which if no particular measures are
taken, ribbon windings would occur. For example, the workstation
computer 19 determines with the aid of the formula: D.sub.SP
k=whole number x bobbin width B.sub.SP/.pi..times.tan cross-winding
angle .alpha./2, that at a bobbin width of, for example, 150 mm and
a cross-winding angle of .alpha.=36.degree., the particularly
critical diameter regions of the cross-wound bobbin 8 are at
D.sub.SP k=147 mm, 294 mm etc.
[0043] After the start of the spinning/winding process the
rotational speed of the cross-wound bobbin 8 is constantly
monitored by means of the sensor mechanism 21 and the current
diameter D.sub.SP of the cross-wound bobbin 8 is constantly
calculated in the workstation computer 19 according to the formula:
D.sub.SP=D.sub.WW.times.n.sub.ww/n.sub.SP.
[0044] If the workstation computer 19 establishes that the diameter
D.sub.SP of the cross-wound bobbin 8 is approaching a critical
diameter region D.sub.SP k, the value of the cross-winding angle
.alpha. is changed to .alpha..sub.1, for example reduced from
.alpha.=36.degree. to .alpha..sub.1=30.degree.. The reduction in
the cross-winding angle .alpha. to .alpha..sub.1 takes place here
by reducing the speed V.sub.FF of the traversing thread guide 18.
In other words, the workstation computer 19 activates the drive 20
of the thread traversing mechanism 16 in the direction of
"deceleration".
[0045] In order to continue to keep the thread tension of the
thread 7 running onto the cross-wound bobbin 8 constant, the
workstation computer 19 simultaneously also activates the drive 13
of the winding roller 11 in the direction of "acceleration". In
other words, the rotational speed V.sub.WW of the winding roller 11
is increased in such a way that the take-up speed V.sub.A of the
thread 7 onto the cross-wound bobbin 8 remains virtually constant
despite the change in the cross-winding angle.
[0046] The invention is not limited to the embodiment shown; in an
alternative embodiment, instead of the workstation computers,
section computers or the central control mechanism of the textile
machine can obviously also be used as the control computer.
* * * * *