U.S. patent application number 11/993486 was filed with the patent office on 2008-12-18 for method for monitoring a yarn transforming process.
This patent application is currently assigned to RITM. Invention is credited to Florent Beauducel, Christophe Vega.
Application Number | 20080308664 11/993486 |
Document ID | / |
Family ID | 35768107 |
Filed Date | 2008-12-18 |
United States Patent
Application |
20080308664 |
Kind Code |
A1 |
Vega; Christophe ; et
al. |
December 18, 2008 |
Method For Monitoring a Yarn Transforming Process
Abstract
At least one yarn is unspooled from at least one bobbin using a
spindle cap. The unspooling speed and, in a coordinated manner,
other parameters associated with the transformation process, are
adjusted according to a quantity representative of the amount of
yarn remaining wound on the at least one bobbin, so that the
unspooling speed remains below limits imposed by unspooling
conditions.
Inventors: |
Vega; Christophe; (Alixan,
FR) ; Beauducel; Florent; (Valence, FR) |
Correspondence
Address: |
HESLIN ROTHENBERG FARLEY & MESITI PC
5 COLUMBIA CIRCLE
ALBANY
NY
12203
US
|
Assignee: |
RITM
Valence
FR
|
Family ID: |
35768107 |
Appl. No.: |
11/993486 |
Filed: |
June 15, 2006 |
PCT Filed: |
June 15, 2006 |
PCT NO: |
PCT/FR06/50603 |
371 Date: |
December 21, 2007 |
Current U.S.
Class: |
242/364.7 |
Current CPC
Class: |
B65H 63/086 20130101;
D01H 13/106 20130101; D01H 13/10 20130101; B65H 63/082 20130101;
B65H 2513/10 20130101; B65H 2511/142 20130101; B65H 2511/142
20130101; B65H 2220/01 20130101; B65H 2701/31 20130101; B65H
2220/02 20130101; B65H 59/384 20130101; D01H 1/30 20130101; D01H
1/244 20130101; D01H 13/32 20130101; B65H 2513/10 20130101; D02G
3/285 20130101; D01H 1/106 20130101 |
Class at
Publication: |
242/364.7 |
International
Class: |
D01H 1/10 20060101
D01H001/10 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 21, 2005 |
FR |
0551677 |
Claims
1. Method for monitoring a yarn transforming process in which at
least one yarn is unspooled from at least one feed bobbin using a
spindle cap mounted rotating freely while being driven by said at
least one yarn, in which variation in quantity of yarn remaining
wound on the at least one feed bobbin or a diameter of said at
least one feed bobbin gives rise to unspooling conditions which
affect equality or performance of the transforming process, wherein
unspooling speed and, in a coordinated manner, other parameters
associated with the transforming process, are adjusted according to
a quantity representative of an amount of yarn remaining wound on
the at least one bobbin, so that the unspooling speed remains below
limits imposed by the unspooling conditions.
2. Method according to claim 1, wherein the representative quantity
is obtained by a direct or indirect measurement of the diameter of
the at least one feed bobbin.
3. Method according to claim 1, wherein the representative quantity
is obtained by a direct or indirect measurement of weight of the at
least one feed bobbin.
4. Method according to claim 1, wherein the representative quantity
is obtained by a direct or indirect measurement of speed of
rotation of the yarn around a periphery of the at least one feed
bobbin, or of the spindle cap which rotates at a same time as the
yarn.
5. Method according to claim 1, wherein the representative quantity
is determined from a value initialized at a start of the
unspooling, and decremented as a function of time according to a
pre-programmed law, or as a function of a representative quantity
of a variation in said quantity.
6. Method according to claim 1, wherein the representative quantity
is determined from a value initialized at the start of the
unspooling, and decremented as a function of measurement and/or
computation of amount of yarn unspooled, or as a function of a
representative quantity of the unspooling speed.
7. Use of the method according to claim 1, for a method of single
twist, double twist, stranding, or covering of yarns in which the
at least one yarn is unspooled from the at least one bobbin using
the spindle cap mounted rotating freely while being driven by the
yarn and using at least one spindle, wherein: speed of rotation of
the spindle and speed of traction of the yarn are controlled by one
or more independent means, in a constant ratio, in order to give
the yarn a constant twist per metre; the speed of rotation of the
spindle and hence proportionally the speed of traction is adjusted
as a function of a quantity representative of the amount of yarn
remaining wound on the at least one feed bobbin.
8. Use of the method according to claim 1, for a method of single
twist, double twist, stranding, or covering of yarns in which the
at least one yarn is unspooled from the at least one feed bobbin
using a spindle cap mounted rotating freely while being driven by
the yarn and using at least one spindle, wherein speed of rotation
of the spindle and speeds of delivery members of the yarn are
controlled by one or more motorizations independent of adjacent
positions, while adjusting the speed of rotation of the spindle and
the speeds of said delivery members as a function of a quantity
representative of the amount of yarn remaining wound on the feed
bobbin in a variable ratio, thereby conferring on the yarn a
variable twist per metre, in order to compensate for variations in
twist per metre caused by the unspooling as a function of said
diameter.
9. Use of the method according to claim 1, for a method of single
twist, double twist, stranding, or covering of yarns in which the
at least one yarn is unspooled from the at least one bobbin using a
spindle cap mounted rotating freely while being driven by the yarn
and using at least one spindle, wherein: speed of rotation of the
spindle and speed of delivery members of the yarn are controlled by
one or more means independent of adjacent positions, in a constant
ratio between the speed of the spindle and the delivery members, in
order to give the yarn a constant twist per meter; the speed of
rotation of the spindle and hence proportionally speed of traction
is adjusted as a function of a quantity representative of the
amount of yarn remaining wound on the feed bobbin; the speed of
rotation of pre-delivery means is adjusted to slacken the yarn from
the spindle to compensate for variations in tension in a balloon
due to the variations in speed of the spindle and thereby to
restore a constant spooling tension.
10. Use of the method according to claim 7, wherein speed is
controlled in accordance with a law of variation of the speed of
rotation of the spindle and proportionally the speed of traction as
a function of the amount of yarn remaining wound on the feed
bobbin, the law comprising a substantially constant zone between an
initial amount of a full bobbin and an intermediate amount, and a
substantially decreasing zone between the intermediate amount and a
minimum amount or zero at an end of unspooling.
11. Device for implementing the method according to claim 1,
wherein each working position is equipped with members controlled
by independent motorizations, so that the transforming process
parameters can be adjusted as a function of a quantity
representative of an amount of yarn remaining wound on at least one
bobbin in the working position, independently of status of adjacent
working positions.
12. Device according to claim 11, wherein monitoring of a spindle
and of delivery members having individual motorizations is
controlled by speed variators, each variator receiving a speed
setpoint from a computation unit.
13. Device according to claim 12, wherein data representative of
the amount of yarn remaining wound on the bobbin is communicated to
the computation unit which modifies each speed setpoint according
to laws of variation as a function of the said diameter.
14. Device according to claim 11, wherein preparation of the
quantity representative of the amount of yarn remaining wound on
the bobbin, and/or computation of production speed and its
transmission to member monitoring means are provided by a computer
or an electronic circuit, or a programmable logic controller.
15. Method for monitoring a transformation process by single twist,
double twist or stranding of yarns in which at least one yarn is
unspooled from at least one feed bobbin and using at least one
spindle, wherein speed of rotation of the spindle and speed of
traction of the yarn are controlled by one or more motorizations
independent of adjacent positions, by adjusting the speed of
rotation of the spindle and speeds of yarn delivery members as a
function of a quantity representative of an amount of yarn
remaining on the feed bobbin in a variable ratio, thereby
conferring on the yarn a variable twist per meter, and of a law of
variation as a function of the quantity representative of the
amount of yarn remaining on the feed bobbing, in order to
compensate for variations in twist per metre caused by unspooling
or respooling operations of twisting process or upstream or
downstream transformation processes.
16. Device according to claim 12, wherein the computation unit
comprises an electronic card or a programmable logic controller.
Description
[0001] The invention relates to the technical field of the
transformation of continuous elongated materials, in particular,
textile yarns, which are designated here below as "yarn", such as,
for example, methods for twisting, for single, double or multiple
twist.
[0002] More particularly, the invention relates to transformation
processes in which the yarn is unspooled from a feed bobbin, passed
through a spindle which twists it upon itself, while being
delivered to a member placed downstream, for example a delivery
member and/or a rewind spooling system, or even to another
transformation process. The combination of the unspooling,
twisting, delivery, rewinding system means constitutes a
transformation unit, which is designated herebelow as "working
position", each working position being independent of or associated
with other adjacent working positions.
[0003] In certain cases, the transformation process is limited by
the unspooling conditions of the feed bobbin or bobbins. In
general, the diameter of the bobbin decreases as the unspooling
proceeds, thereby affecting the yarn unspooling conditions on the
periphery of the bobbin. In fact, for a given delivery speed, the
rotation of the unspooling point around the bobbin, that is, the
point where the yarn leaves the periphery of the bobbin,
accelerates as the bobbin diameter decreases, thereby increasing,
for example, the unspooling tensions, the irregularity of these
tensions, and also the twisting of the yarn upon itself due to this
rotation. This influence may affect the quality of the
transformation process and/or limit its performance.
[0004] Such an influence is particularly important for multiple
twisting processes, in particular for double twisting processes.
Reference can be made to FIG. 1 to understand the principle
thereof, which is recalled here, and which is known to a person
skilled in the art.
[0005] A feed bobbin (2), formed by the winding of a yarn (1)
around a hollow spindle, is placed in a support (3) itself
supported by the pin of a spindle (4). This support (3) is
coaxially subjected to the pin of the spindle (4) by means such as
ball bearings, and it is prevented from rotating about itself by
retaining means acting by gravity, or by a magnetic or mechanical
force, so that the bobbin (2) and its support (3) do not
rotate.
[0006] The yarn (1) unspooled from the bobbin (2) is introduced
into a channel made in the pin of the spindle (4), and exits via an
orifice (5) opening radially in a cylindrical or conical zone
called reserve (6) placed below the support of the bobbin (3). The
yarn winds a few fractions of turns on the reserve (6) then forms
an arc circumventing the bobbin (2) and its support (3), to meet a
fixed thread guide (7), before being pulled by downstream members
(8, 9) at a given speed V (delivery speed). The downstream members
often consist of a pre-delivery member (8), designed to decrease
the yarn tension, and a positive delivery member (9), the latter
guaranteeing the speed V.
[0007] Thanks to the rotation of the spindle (4), the yarn (1)
rotates about the bobbin (2) and its support (3) forming a
"balloon". The rotation causes the first twisting of the yarn on
itself between the inlet of the spindle and its radial orifice (5)
and a second twisting of the yarn on itself between the radial
orifice (5) and the fixed thread guide (7). Thus, if the spindle
rotates at N rev/min and if the yarn is pulled at V metres/min, in
each minute the yarn receives 2 N twists distributed over V metres,
or 2N/V twists per metre.
[0008] The stability of the process is based on the balance between
the tension due to the centrifugal force created by the rotation of
the balloon, and the yarn retaining force between the feed bobbin
and the said balloon. This retaining force is distributed between
the unspooling forces, the friction of the yarn in the winding on
the reserve, and auxiliary braking means.
[0009] When the unspooling is performed using a device called
"spindle cap" by a person skilled in the art, experience shows that
the forces generated by the unspooling of the bobbin are mainly
associated with the rotation of the yarn unspooling between the
periphery of the bobbin and the pin of the spindle and, for a given
delivery speed, tend to increase as the bobbin is emptied, that is,
as its outside diameter decreases.
[0010] As shown in FIG. 1, the spindle cap is formed of an arm (10)
which can rotate freely about the pin of the spindle (4) and
carries a thread guide (11) at its end. The yarn (1) passes through
the thread guide (11), which has the effect of eliminating the
friction of the yarn along the periphery and the side of the
bobbin.
[0011] The "spindle cap" (10) rotates at the same time as the yarn
(1) to accompany it in its unspooling, this rotation generally
being braked by a friction, magnetic or other device, supplying a
resistive torque intended to generate the braking force necessary
for the equilibrium of the process.
[0012] In fact, for a given resistive torque, the yarn tension
necessary to make the spindle cap (10) rotate increases as the
outside diameter of the bobbin decreases, due to the decrease in
the lever arm which corresponds to the radius of the bobbin (2). In
consequence, as the diameter of the bobbin (2) decreases, the yarn
tension (1) at the spindle inlet increases, modifying the
equilibrium of the forces, the winding of the yarn in the reserve
decreasing to a threshold which can cause the yarn to break.
[0013] At the same time, the speed of the spindle cap increases,
thereby increasing the undesirable losses by friction and
vibrations, and affects the stability of the system, giving rise to
the possibility of reaching unacceptable limits from the textile or
mechanical standpoint.
[0014] To solve this problem, the production speed is limited so
that the speed of rotation of the spindle cap and/or the tensions
generated by the unspooling remain below permissible values, while
observing that this speed or these limit tensions are only reached
at the end of unspooling of the feed bobbin.
[0015] To try to correct these drawbacks, as it appears from
patents EP1045053 and JP200307933, means have been proposed for
motorizing the spindle cap. These solutions are complex to
implement and particularly costly.
[0016] In connection with the object of the present invention, a
device and a method have been found for monitoring a yarn
transforming process which serve to solve this problem rationally
and to obtain a significant increase in the productivity of the
yarn transformation installations, particularly in the case of
twisting processes such as double twist, in which the unspooling is
carried out using a spindle cap.
[0017] According to the invention, the method for monitoring the
process consists in adjusting the unspooling speed and, in a
coordinated manner, the other parameters associated with the
transformation process, as a function of a quantity representative
of the amount of yarn remaining wound on at least one of the
bobbins, so that the said unspooling speed remains below the limits
imposed by the unspooling conditions on the said bobbin.
[0018] According to the invention, the quantity representative of
the amount of yarn remaining wound on a bobbin may be its diameter,
its weight, its mass, the length of yarn wound on the bobbin, or
any other quantity, which can be obtained for example by: [0019] a
direct or indirect measurement of the diameter of the bobbin;
[0020] a direct or indirect measurement of the weight of the
bobbin; [0021] a direct or indirect measurement of the speed of
rotation of the yarn around the periphery of the bobbin, or of the
spindle cap which rotates at the same time as the yarn; [0022] a
quantity determined from a value initialized at the start of the
unspooling (full bobbin), and decremented as a function of the time
according to a pre-programmed law, or as a function of a
representative quantity of the variation in this quantity; a
quantity determined from a value initialized at the start of the
unspooling (full bobbin), and decremented as a function of the
measurement and/or computation of the amount of yarn unspooled, or
as a function of a representative quantity of the unspooling
speed.
[0023] According to a preferred embodiment of the invention, the
combination of means implemented for the transformation of a yarn
(unwinding, spindle, delivery means, etc.) constitute a
self-contained working position, that is, these members are
individually controlled by independent means, so that the
transformation process parameters can be adjusted as a function of
a quantity representative of the amount of yarn remaining wound on
at least one of the bobbins used in working position, independently
of the status of the adjacent working positions.
[0024] According to a particularly advantageous embodiment of the
invention applied to twisting processes using a spindle, the
process monitoring method consists in: [0025] controlling the speed
of rotation of the spindle and the speed of traction of the yarn by
one or more independent means, in a constant ratio, in order to
give the yarn a constant twist per metre; [0026] adjusting the
speed of rotation of the spindle (and hence proportionally the
speed of traction) as a function of a quantity representative of
the amount of yarn remaining wound on the feed bobbin.
[0027] According to this application, the law of variation of the
speed of rotation of the spindle (and proportionally the speed of
traction) as a function of the amount of yarn remaining wound on
the feed bobbin, comprises a substantially constant zone between
the initial amount of the full bobbin and an intermediate amount,
and a substantially decreasing zone between the said intermediate
amount and the minimum amount (or zero) at the end of
unspooling.
[0028] Another problem that the invention proposes to solve is to
compensate for the variation in twisting of the yarn resulting from
the acceleration of the rotation of the unspooling point around the
bobbin as its diameter decreases.
[0029] To solve such a problem, according to one embodiment, the
speed of rotation of the spindle and the speed of traction of the
yarn are controlled by one or more motorizations independent of
those of the adjacent positions, by adjusting the speed of rotation
of the spindle and the speeds of the delivery members as a function
of a quantity representative of the amount of yarn remaining on the
feed bobbin in a variable ratio, thereby conferring on the yarn a
variable twist per meter, as a function of the said quantity
representative of the amount of yarn remaining on the feed bobbin,
in order to compensate for the variations in twist per metre caused
by the unspooling as a function of the said diameter.
[0030] According to another embodiment, the speed of rotation of
the spindle and the speed of traction of the yarn are controlled by
one or more motorizations independent of those of the adjacent
positions, by adjusting the speed of rotation of the spindle and
the speeds of the delivery members as a function of a quantity
representative of the amount of yarn remaining on the feed bobbin
in a variable ratio, thereby conferring on the yarn a variable
twist per meter, and of a law of variation as a function of the
said quantity representative of the amount of yarn remaining on the
feed bobbin, in order to compensate for the variations in twist per
metre caused by the unspooling or respooling operations of the
twisting process or the upstream or downstream transformation
processes.
[0031] The invention is summarized below in greater detail in
conjunction with the figures and drawings as follows:
[0032] FIG. 1 is a schematic view of a double twist process
according to the prior art.
[0033] FIG. 2 shows a diagram illustrating the production speed
limits as the unspooling of the feed bobbin proceeds, according to
the prior art.
[0034] FIG. 3 shows a diagram illustrating the production speed
limits as the unspooling of the feed bobbin proceeds, according to
the invention.
[0035] FIG. 4 is a schematic view of an embodiment of the invention
applied to the double twist process.
[0036] The invention is described here in detail in its application
to the double twist process. This exemplary application is
non-limiting, and other applications can be considered such as
single twist, multiple twist, direct stranding, covering. In
general, the invention applies to any yarn transforming process in
which at least one yarn is unspooled from at least one bobbin using
a spindle cap, in which the variation in the quantity of yarn
remaining wound on at least one of the feed bobbins (or the
diameter of the said bobbin) gives rise to unspooling conditions
which affect the quality or performance of the transformation
process.
[0037] Reference can be made to FIG. 1 and to the corresponding
analysis, the same numerals being resumed in the rest of the
description.
[0038] In the diagrams shown in FIGS. 2 and 3, the time (t) is
plotted on the x-axis and the production speed (V) is plotted on
the y-axis. The speed (V) equally represents (to the nearest
proportional factor) the speed of the spindle or the delivery speed
because, to obtain a given torsion, these two speeds are related by
a fixed ratio.
[0039] At the start of production (20), the bobbin (2) is full
(maximum outside diameter). As production proceeds, the diameter of
the bobbin (2) decreases, until the end of the production (21)
where it reaches its final value (which is generally close to or
equal to the diameter of the empty bobbin).
[0040] In general, the production speed (V) is limited by the
centrifugal forces generated by the rotation of the balloon. The
centrifugal force tends to increase the diameter of the balloon and
the tensions in the yarn (1). It is therefore necessary to limit
the speed of rotation to remain below a diameter corresponding to
the available space (particularly the centreline distance between
adjacent spindles). The speed of rotation must also be limited to
remain below the tensions acceptable by the yarn (to avoid breaking
it or jeopardizing its strength by subjecting it to excessive
stresses). This limit depends on the nature and count of the yarn,
and on the geometry of the device. It does not depend on the
diameter of the feed bobbin (2) and is therefore substantially
constant over time. This speed limit is shown by the line (22).
[0041] The production speed is also limited by the speed of
rotation of the unspooling point, due for example to the change in
the resultant unspooling forces which, for a given delivery speed,
increase as the diameter of the bobbin (2) decreases. For a given
speed of rotation limit or traction force limit, the permissible
production speed (corresponding here to the delivery speed)
decreases as the diameter of the bobbin (2) decreases and therefore
decreases as a function of time. The speed limit is shown by the
line (23).
[0042] In certain configurations (not shown), the curve of the
speed limit due to unspooling (23) may remain above the limit speed
(22) due to the rotation of the balloon throughout the time between
the start (20) and end (21) of production. In this case, it is
possible to set a constant production speed (25), according to the
prior art.
[0043] In other configurations (shown in FIGS. 2 and 3), the curve
of the speed limit due to unspooling (23) falls below the limit due
to the rotation of the balloon (22) from a point (24) corresponding
to a certain quantity of yarn remaining wound on the bobbin (2). In
this case, according to the prior art, it is necessary to set a
constant production speed, lower at any point between the start
(20) and the end (21) of production than the lowest of the limits.
In other words, a constant speed limit (25) is adopted, that is,
below the curve (23) at the end (21) of production (FIG. 2).
[0044] According to the invention, the process monitoring method
consists in: [0045] controlling the speed of rotation of the
spindle (4) and the speed of the yarn traction means (8, 9, etc.)
by one or more motorizations (12, 13, 14, etc.) independent of
those of the adjacent positions, in a constant speed ratio, in
order to give the yarn a constant twist per metre; [0046] adjusting
the speed of rotation of the spindle (4) (and hence proportionally
the traction speed) as a function of a quantity representative of
the amount of yarn remaining wound on the feed bobbin (2).
[0047] According to a preferred embodiment, provided as a
non-limiting example, the control of the spindle (4) and the
traction means (8, 9, etc.) have individual motorizations (12, 13,
14, etc.) controlled by speed variators (15, 16, 17), each
receiving a setpoint from a computation unit (18), such as an
electronic card, programmable logic controller or other. The data
representative of the amount of yarn remaining wound on the bobbin
(2) is communicated to the computation unit (18) which modifies the
speed setpoints according to the laws of variation as a function of
the said quantity.
[0048] According to the invention (FIG. 3), the law of variation
(26) of the speed of rotation of the spindle (and proportionally
the speed of traction) as a function of the amount of yarn
remaining wound on the feed bobbin (2), comprises a substantially
constant zone between the start of production of the initial amount
of the full bobbin and an intermediate amount (24), and a
substantially decreasing zone between the said intermediate amount
(24) and the minimum amount (or zero) at the end of unspooling
(21).
[0049] According to another advantageous application of the
invention to twisting processes by single twist or by multiple
twists, the process control method consists in:
controlling the speed of rotation of the spindle (4) and the speed
of traction of the yarn (8, 9, etc.) by one or more motorizations
(12, 13, 14, etc.) independent of those of the adjacent positions,
by adjusting the speed of rotation of the spindle (4) and the
speeds of the yarn delivery members (8, 9, etc.) as a function of a
quantity representative of the amount of yarn remaining wound on
the feed bobbin (2) in a variable ratio, thereby conferring on the
yarn a variable twist per meter, in order to compensate for the
variations in twist per meter caused on the yarn by the unspooling
as a function of the said diameter.
[0050] Advantageously, such a compensation consists in establishing
a law of variation of the ratio between the delivery speed and the
spindle speed in order to compensate for variations in torsion
caused by all the rewinding, unspooling and transformation phases
upstream or downstream of the twisting process.
[0051] According to another application of the invention to
twisting processes by multiple twist, the process control method
consists in: [0052] controlling the speed of rotation of the
spindle (4) and the speed of the delivery members of the positive
yarn (9) by one or more means (12, 14, etc.) independent of those
of the adjacent positions, in a constant ratio between the speed of
the spindle (4) and the positive delivery and spooling means (9),
in order to give the yarn a constant twist per meter; [0053]
adjusting the speed of rotation of the spindle (4) (and hence
proportionally the speed of traction to ensure a constant twist) as
a function of a quantity representative of the amount of yarn
remaining wound on the feed bobbin (2); [0054] adjusting the speed
of rotation of the pre-delivery means (8) to slacken the yarn from
the spindle (4) to compensate for the variations in tension in the
balloon due to the variations in speed of the spindle (4) and
thereby to restore a constant spooling tension.
[0055] According to the invention, the quantity representative of
the amount of yarn remaining wound on the bobbin (2) may, for
example, be: [0056] A direct or indirect measurement of the said
diameter of the bobbin (2). This measurement can be taken for
example by optical means, by ultrasound or by any other means. The
measurement may be continuous or discrete, that is, detecting the
passage through one or more intermediate diameters, for example, by
electrical cells of which the beam is cut when the bobbin reaches
the said intermediate diameter or diameters. [0057] A direct or
indirect measurement of the weight of the bobbin. This measurement
can be taken by measuring the weight of the bobbin alone, or with
its support, or by monitoring the weight of the complete spindle.
[0058] A direct or indirect measurement of the speed of rotation of
the yarn around the periphery of the bobbin (2), or of the spindle
cap (10), by optical, magnetic or other means.
[0059] In the case in which the balloon surrounds the bobbin (2)
and its support (3), the measurement means mentioned above may be
placed outside the said support and outside the balloon formed by
the yarn. They may also be mounted with the bobbin (2) or its
support (3) inside the said balloon, in which case, the data may be
transmitted by any infrared, radiofrequency or other means.
[0060] According to the invention, the quantity representative of
the amount of yarn remaining wound on the bobbin (2) may also be
determined by a computation, from data representative of the
variation in this quantity. For example, for a given production
speed, this quantity of yarn on the feed bobbin decreases in
accordance with the weight or length removed per unit of time.
Thus, the amount of yarn remaining wound on the bobbin and hence
the variation in its weight and/or in its diameter, can be
calculated, for example, from: [0061] a quantity determined from a
value initialized at the start of the unspooling (full bobbin), and
decremented as a function of the time according to a pre-programmed
law; [0062] a quantity determined from a value initialized at the
start of the unspooling (full bobbin), and decremented as a
function of the measurement and/or computation of the amount of
yarn unspooled.
[0063] The calculation can be carried out in the computer (18) or
by any other external means and communicated thereto, for example
by a network (19).
[0064] The determination of the quantity representative of the
amount of yarn remaining wound on the bobbin, the calculation of
the production speed and its transmission to the means for
monitoring the members, particularly the spindle (4) and the
delivery system (8, 9, etc.) may be provided by all appropriate
means such as computers (18) or electronic circuits, a programmable
logic controller or other, associated with sensors, metering
systems, etc.
[0065] The advantages clearly appear from the description.
[0066] Thanks to the invention, it is possible to optimize the
process and particularly the production speed, throughout
production. It is in particular possible to minimize the
consequences of limitations resulting from factors inherent in the
unspooling and which only act for certain bobbin diameters, for
example at the end of unspooling.
[0067] The invention can be applied to machines equipped with
collective motorization means. It is extremely advantageous for
machines consisting of self-contained working positions, that is,
equipped with individual motorization means. In fact, each working
position is thus monitored to obtain the optimal production speed,
according to the state of unspooling of its own bobbin.
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