The present invention relates to a textile machine and
the control method thereof.
It is known that in textile machines such as needle looms,
among which also the crocheting machines are included, formation of the textile
product takes place by mutual interlacing, following predetermined patterns, of
a plurality of warp and weft yarns, suitably engaged by respective weaving or knitting
members; the latter are for example the healds mounted on one or more heald frames,
a predetermined number of sickles and at least one needle.
Also present are auxiliary members such as weft-yarn knocking-over
devices and compacting reeds.
These weaving members are operated, through appropriate
actuators or kinematic mechanisms of the mechanical type, through synchronised cyclic
movements to cause mutual intertwining of the warp yarns and weft yarns following
the desired knitting pattern.
The weft yarns are fed to the respective weaving members
by a plurality of bobbins mounted on a rack-shaped structure called "unwinding creel",
while the warp yarns are unwound from a plurality of beams supported by a beam-carrying
unwinding creel.
It is also provided that appropriate take-down rollers
should cause sliding of the textile product and progressive supply of same to the
machine exit.
The bobbins on which the weft yarns are wound are free
to rotate about their longitudinal rotation axis, and the tension with which the
weft yarns are fed to the respective sickles is determined by the rotation speed
of the rollers that are interposed between the bobbins and the sickles and are disposed
close to each other so as to engage the weft yarns.
Rotation of these rollers is usually caused by a kinematic
connection between said rollers and the main shaft of the textile machine; since
this connection is of a purely mechanical type, it keeps a fixed position during
production of the whole fabric.
Therefore, each sickle always receives the same amount
of weft yarn in a time unit and, to vary this amount, the machine is to be stopped
and the kinematic connection ratios between the main shaft and said rollers are
to be modified.
Likewise, the warp yarns too are fed to the healds through
rollers disposed suitably close to each other and the finished product is picked
up from the machine by a quite similar roller member.
Both the warp yarn feeding member and the textile-product
take-down member are mechanically connected with the main shaft, so that the follow-up
ratio (i.e. the ratio between the number of revolutions carried out in the time
unit by the feeding/take-down rollers and the number of revolutions carried out
in the time unit by the main shaft) keeps constant over the whole working of the
textile product.
Consequently, it is not possible to alter tensioning of
the weft and warp yarns when supplied to the respective bars without stopping operation
of the machine, neither is it possible to modify the pulling tension applied when
the finished product is removed from the machine.
Therefore, by adopting these modalities of use of the loom
it is not possible to alter the fabric compactness or density both in a transverse
direction and in a direction parallel to the extension of the textile product, without
stopping operation of the machine.
In addition, exactly due to the fact that the warp and
weft yarns are fed to the healds and sickles respectively at a constant tension
and the textile product is caused to slide between the take-down rollers at a constant
tension in time, it is not possible to obtain particular aesthetic effects through
a controlled variation of the fabric compactness, without stopping operation of
the machine, said aesthetic effects comprising alternations of thinner and more
compact regions, narrowing or shrinkage of the textile product along a direction
substantially perpendicular to the movement direction in which the textile product
itself is moved by the take-down rollers, etc.
Document
US 4,577, 665
discloses a needle loom in which both the weaving members and the feeding
members are mechanically connected to the main shaft, the latter being driven by
an electric motor.
Document
US 5,069,257
discloses a loom in which the rotation of the beams is controlled according
to the tension of the warp threads, by means of a sensor and a controller connected
thereto for regulating the rotation of said beams.
Document
DE 198 16 666
discloses a narrow fabric loom provided with control system for making
curved clockwise and counter-clockwise sections in the textile product, by means
of rollers which can have either a cylindrical or a conical shape.
Document
US 2003/0075231
discloses a narrow fabric loom comprising a draw-off device having elastic
belts for producing curved woven composites; the radius of curvature of the woven
composites can be adjusted by modifying the rotational speed differential between
extension drive mechanisms and driving rollers.
Document
WO 02/052082
discloses a textile machine in which rotation of a beam (on which the
thread is wound) is controlled according to the tension of the threads detected
by means of an elastic member and a magnetic sensor.
Document
US 5,947,161
discloses a ribbon loom provided with a transport roller for engagement
with a bobbin supply thread; the external diameter of the roller can be varied by
means of a resilient mechanical regulation device.
It is an aim of the present invention to solve the above
mentioned drawbacks. In particular, the present invention aims at making available
a textile machine and the control method thereof, that are able to vary tensioning
of the weft yarns when supplied to the sickles, without stopping operation of the
machine.
Another aim of the invention is to provided a textile machine,
and the control method thereof, allowing the take-down tensioning of the textile
product coming out of the machine to be varied without stopping operation of the
machine.
It is a further aim of the invention to provide a textile
machine and the control method thereof, allowing articles of manufacture having
portions of different compactness, in a direction both parallel and transverse
to the extension of the product itself, to be made in an automatic manner.
The foregoing and further aims are substantially achieved
by a textile machine, and the control method thereof, in accordance with the features
set out in the appended claims.
Further features and advantages will become more apparent
from the detailed description of a preferred embodiment of a textile machine and
the control method thereof, given hereinafter by way of non-limiting example with
the aid of the accompanying drawings, in which:
- Fig. 1 is a partly diagrammatic perspective view of a textile machine in accordance
with the present invention;
- Fig. 2 is a detailed view of a first operating step of the machine in Fig. 1;
- Fig. 3 is a detailed view of a second operating step of the machine in Fig.
1;
- Fig. 4a diagrammatically shows a section along line IVa-IVa of the machine in
Fig. 1;
- Fig. 4b diagrammatically shows a section along line IVb-IVb of the machine in
Fig. 1;
- Fig. 4c diagrammatically shows a section along line IVc-IVc of the machine in
Fig. 1;
- Fig. 5 is a block diagram of the machine in Fig. 1;
- Fig. 6 diagrammatically shows the logic structure of a memory employed in the
machine in Fig. 1.
With reference to the drawings, a textile machine in accordance
with the present invention has been generally identified by reference numeral 1.
The textile machine 1 that preferably is a needle loom,
comprises a plurality of frames 2, on each of which a plurality of healds 3 is mounted
; it is to be noted that in Fig. 1, for the sake of clarity, only a horizontal portion
of each frame 2 has been shown.
Each heald 3 has a slot 4 adapted to engage a respective
warp yarn 5. Each frame 2 is moved in a substantially vertical direction, between
two or three operating positions; corresponding to each of said operating positions
is a different height at which the slots of healds 3 supported by said frame 2 are
positioned.
Frames 2 can be directly connected with the main shaft
12 of loom 1, by means of a cam chain, or they can be moved by electromechanical
actuators, suitably operated in accordance with preset programs.
The machine 1 further comprises at least one sickle 6 that
at an end thereof has an engagement portion 6a to guide the weft yarn 19 towards
the warp yarns 18.
Sickle 6 carries out a reciprocating motion so that the
engagement portion 6a cyclically moves close to' and away from the warp yarns 18
following an arched trajectory lying in a substantially horizontal plane.
Also provided is a needle 8 disposed side by side with
said warp yarns 18 to hold the weft yarn 19 and enable interlooping of same with
the warp yarns 18.
A knocking-over device 200 ensures engagement of the weft
yarn 19 with the hooked end portion 8a of needle 8; a compacting reed 201 pushes
the weft yarn 19 onto the already made fabric portion 5 to improve mutual engagement
between the warp yarns 18 and the weft yarn 19 itself.
The warp yarns 18, depending on the type of product to
be made, can be disposed on two or three rows; if two rows of warp yarns 18 are
employed, each frame 2 will be shiftable between two operating positions, while
if three rows of warp yarns 18 are employed, each frame 2 will be shiftable between
three operating positions.
The warp yarns 18 of each row are unwound from a corresponding
beam 11; the beams 11 are supported by a beam-carrying creel 203. For the sake of
clarity, a single warp yarn 18 of each row has been.shown in Fig. 1.
Operation of the textile machine 1 is now briefly described.
During a first operating step of loom 1 (Fig. 2), sickle
6 takes a first operating position, at which the weft yarn 19 portion guided by
sickle 6 is positioned transversely of the warp yarns 18, so as to engage the latter
for making a new weft row of fabric 5.
Under this condition, the knocking-over device 200 exerts
a downward pressure on the weft yarn 19, so that the latter is engaged with the
hooked portion 8a of needle 8.
In a second operating step (Fig. 3), the sickle 6 is retracted
so as to move its engagement surface 6a away from needle 8; concurrently, the knocking-over
device 200 moves upwardly, allowing the needle 8 to take a retracted position, guiding
the weft yarn 19 until bringing it into contact with the already made fabric portion
5.
Subsequently, the compacting reed 201 is moved close to
fabric 5, to press the weft yarn 19 against the already made fabric portion 5, and
lock the new position taken by the weft yarn 19 in fabric 5.
Finally, the compacting reed 201 moves away from the fabric
5, and healds 3 are moved in accordance with the predetermined work program, thus
starting a new operating cycle of the machine 1 for manufacture of a subsequent
weft row.
The fabric 5 is therefore defined by a succession of weft
rows in engagement with said warp yarns 18; each weft row is defined by the portion
of weft yarn 19 interlooped with the warp yarns 18 in a working cycle.
Therefore, each weft row of the fabric 5 corresponds to
performing all the above operating steps once.
Each weft yarn 19 is wound around a corresponding bobbin
14, mounted on a unwinding creel 15 and is progressively fed to sickle 6 for manufacture
of the textile product 5.
Interposed between beams 11 and frames 2 is a first feeding
member 20 to supply the healds with the respective warp yarn 18.
In the preferred embodiment, the first feeding member 30
comprises a first roller 21, a second roller 22, close to the first roller 21, and
a third roller 23 close to the second roller 22.
The first roller 21 has a first bearing arc 21a with which
the warp yarn 18 is engaged during supply of said warp yarn to sickle 6; the first
bearing arc 21 has a first end 21b and a second end 21c confining the roller portion
on which the warp yarn 18 lies.
Likewise, the second roller 22 has a second bearing arc
22a having a first end 22b and a second end 22c; the third roller 23 has a third
bearing arc 23a having at least one end 23b.
Preferably, as shown in Fig. 4a, rollers 21, 22 and 23
are disposed close to each other so that the second end 21c of the first bearing
arc 21a is coincident with the first end 22b of the second arc 22a and the second
end 22c of the second bearing arc 22a is coincident with the first end 23b of the
third arc 23a.
A first electromechanical actuator 20 is connected with
the first feeding member 20, to drive said rollers 21, 22 and 23 in rotation and
supply the healds 3 with the respective warp yarn 18 at a given tension that, as
better clarified in the following, can be varied during manufacture of the textile
product 5.
In more detail, the first electromechanical actuator 30
is made up of an electric motor 31, preferably a brushless motor, and of an electric
activation device 32 for powering and controlling motor 31. The electric motor 31
is provided with an output shaft 33 that, when powered by said activation device
32, is driven in rotation.
The output shaft 33 is connected with the first and preferably
the third rollers, 21, 23, of the first feeding member 20, whereas the second roller
22 is idly mounted on a respective rotation axis; therefore by varying the rotation
speed of the output shaft 33 it is possible to regulate tensioning of the warp yarns
18 when supplied to healds 3.
A second feeding member 40 is interposed between the bobbins
14 and sickle 6 to supply the latter with the weft yarn 19.
The second feeding member 40 (Fig. 4b) is made up of a
first roller 41, a second roller 42 and a third roller 43; the first roller 41 has
a first bearing arc 41a for the weft yarn 19 confined by a first and a second ends
41b, 41c.
The second roller 42 has a second bearing arc 42a confined
by a first and a second ends 42b, 42c; the third roller 43 has a third bearing arc
43a having at least one first end 43b.
Conveniently, the first, second and third rollers 41, 42,
43 are disposed close to each other so that the second end 41c of the first bearing
arc 41a is coincident with the first end 42b of the second bearing arc 42a, and
the second end 42c of the second bearing arc 42c is coincident with the first end
43b of the third bearing arc 43a.
A second electromechanical actuator 50 is connected with
the second feeding member 40, to drive said rollers 41, 42, 43 in rotation and supply
sickle 6 with the respective weft yarn 19 at a given tension that, as will be better
clarified in the following, can be varied during manufacture of the textile product
5.
In more detail, the second electromechanical actuator 50
is made up of an electric motor 51, preferably a brushless motor, and of an electric
activation device 52 for powering and controlling motor 51.
The electric motor 51 is provided with an output shaft
53 that, when powered by said activation device 52, is driven in rotation
The output shaft 53 is connected with the first and preferably
the third rollers 41, 43 of the second feeding member 40, whereas the second roller
42 is idly mounted on a respective rotation axis; by varying the rotation speed
of the output shaft 53 it is therefore possible to regulate tensioning of the weft
yarn 19 when supplied to sickle 6.
A take-down member 60 is positioned close to said sickle
6, knocking-over device 200, compacting reed 201 and needle 8, to engage the textile
product 5 and draw it to the exit of machine 1.
The take-down member 60 (Fig. 3c) consists of a first roller
61, a second roller 62 and preferably a third roller 63; the first roller 61 has
a first bearing arc 61a for the textile product 5 having a first and a second ends
61b, 61c.
The second roller 62 has a second bearing arc 62a, delimited
by a first and a second ends 62b, 62c; the third roller 63 has a third bearing arc
63a having at least one first end 63b.
Conveniently, the first, second and third rollers 61, 62,
63 are disposed close to each other so that the second end 61c of the first bearing
arc 61a is coincident with the first end 62b of the second bearing arc 62a, and
the second end 62c of the second bearing arc 62a is coincident with the first end
63b of the third bearing arc 63a.
A third electromechanical actuator 70 is connected with
the take-down member 60, to drive said rollers 61, 62, 63 in rotation and draw the
textile product 5 according to a given tensioning that, as better clarified in the
following, can be varied during manufacture of the textile product 5.
In more detail, the third electromechanical actuator 70
is made up of an electric motor 71, preferably a brushless motor, and of an electric
activation device 72 for powering and controlling motor 71. The electric motor 71
is equipped with an output shaft 73 that, when powered by said activation device
72, is driven in rotation.
The output shaft 73 is connected with the first and preferably
the third rollers 61, 63 of the second feeding member 60, whereas the second roller
62 is idly mounted on a respective rotation axis; by varying the rotation speed
of the output shaft 73 it is therefore possible to regulate the pulling tension
of the textile product 5. It will be appreciated that motors 31, 51 and 71 can be
either brushless motors or stepping motors.
The textile machine 1 further comprises a main shaft 12
driven in rotation by appropriate actuating means (not shown in the drawings) preferably
comprising an electric motor.
The main shaft 12 is used to provide a reference to the
synchronised movement of the different members of which the textile machine is made
up; in fact, frames 2, sickle 6, knocking-over device 200, compacting reed 201 and
needle 8 directly or indirectly derive their position and movement speed from the
angular position PA and the rotation speed of the main shaft 12.
Connection between the main shaft 12 and said members 2,
6, 200, 201 and 8 can be of an exclusively mechanical type, consisting of appropriate
intermediate kinematic mechanisms, such as glider chains; alternatively, the angular
position PA of the main shaft 12 can be detected by a sensor 13 (an encoder, for
example) so that a control of the electronic type active on electromechanical actuators
connected with said members can keep the latter synchronised with the main shaft
12.
As will be apparent in the following, also the movement
of the feeding members 20, 40 and take-down member 60 is synchronised with the rotation
of the main shaft 12.
In order to control the whole operation of the machine
1 and the members of which it is comprised, the machine 1 is equipped with a control
apparatus 80 that, in addition to said first, second and third electromechanical
actuators 30, 50, 70, also comprises a controller 90.
Controller 90 is first of all provided with a memory 100
on which the necessary parameters for regulating operation of the machine 1 are
stored.
In more detail, memory 100 contains a plurality of records
110, each of which is associated with a respective weft row of the textile product;
records 110 are then disposed in an orderly sequence corresponding to the sequence
of the weft rows of the textile product 5.
Each record 110 consists of a plurality of fields, each
of which is designed to contain a respective operating parameter of a device of
the machine 1.
A first field 112a contains a main parameter 111, representative
of the weft row corresponding to record 110; the main parameter 111 is conveniently
a progressive numeric code: record 110 having the main parameter 111 equal to "1"
corresponds to the first weft row that is made,' the record having the main parameter
equal to "2" corresponds to the second weft row that is made.
A second field 112b of record 110 contains a displacement
parameter PS, representative of a vertical displacement of at least one frame 2,
carried out to make the weft row associated with record 110; the movement width
of frames 2 in fact is varied during manufacture of the textile product 5 to obtain
particular geometries or decorations thereon, and the displacement parameters PS
represent the amount of these displacements.
A third field 112c of record 110 contains a first follow-up
parameter PI1, associated with the weft row corresponding to said record 110, and
representative of a follow-up ratio between the output shaft 33 of motor 31 of the
first electromechanical actuator 30 and the main shaft 12.
The first follow-up parameter PI1 is determined, row by
row, so as to continuously adjust the follow-up ratio between the output shaft 33
of motor 31 of the first electromechanical actuator 30 and the main shaft 12.
For the purpose, controller 90 is equipped with first calculation
means 91 to calculate the first follow-up parameter PI1 depending on the displacement
parameter PS belonging to the same record 110; in fact it is important that the
amount of the warp yarn 18 supplied by the first feeding member 20 to healds 3 should
be suitably adjusted depending on the displacements carried out by frames 2.
A fourth field 112d of record 110 holds a second follow-up
parameter PI2, associated with the weft row corresponding to this record 110 and
representative of a follow-up ratio between the output shaft 53 of motor 51 of the
second electromechanical actuator 50 and the main shaft 12.
For determining this second follow-up parameter PI2, controller
90 is provided with second calculation means 92, preferably depending on appropriate
data inputted by the user and representative of the type of aesthetic effect or
ornament that is wished to be obtained in fabric 5.
A fifth field 112e of record 110 holds a third follow-up
parameter PI3, associated with the weft row corresponding to this record 110 and
representative of a follow-up ratio between the output shaft 73 of motor 71 of the
third electromechanical actuator 70 and the main shaft 12.
In order to determine the value of said third follow-up
parameter PI3, the control apparatus 80 is provided with third calculation means
93; said means carries out calculation of the third follow-up parameter PI3 in such
a manner that it is proportional to the density of stitches per centimetre as inputted
by the operator.
In the light of the above, it is apparent that memory 100
of controller 90 has a logic structure quite similar to a table, in which each row
is defined by a record 110 and holds all the parameters relating to working of a
corresponding weft row of the textile product; on the other hand, each column holds
an orderly sequence of parameters relating to a particular element of the machine
or the textile product, each of which refers to a specific weft row: the first column
holds the main parameters 111 representative of the weft rows and a sequential ordering
of same, the second column holds the displacement parameters PS of frames 2, the
third column holds the first follow-up parameters PI1, the fourth column holds the
second follow-up parameters PI2 and the fifth column holds the third follow-up parameters
PI3.
It will be appreciated that the first, second and third
calculation means 91, 92, 93 can be incorporated into controller 90 and be therefore
positioned close to said members 6, 8, 200, 201.
In this case, once insertion in controller 90 of the numeric
chains defined by the succession of displacement parameters PS for frames 2 has
occurred, controller 90 is able to determine in an independent manner and row by
row, the value that the follow-up parameters PI1, PI2, PI3 must take.
Alternatively, the calculation means 91, 92, 93 can be
incorporated in a computer, typically a personal computer (PC), placed at a remote
position with respect to members 6, 8, 200, 201 and to the controller 90 associated
therewith.
In this way, the computer which is tasked with the most
complicated calculations can be positioned in a different place with respect to
the mechanical components of the textile machine 1, thus avoiding the correct operation
of the computer itself being impaired by vibrations generated by the quick movements
of members 6, 8, 200, 201 or the dust formed following working of the different
yarns.
The results generated by said computer can be transmitted
to controller 90 to be stored in memory 100, through a telematic connection, or
by means of a conventional solid state, semiconductor, magnetic or optical storage
medium that is transferred from the computer to processor 90 by an operator.
Once the different displacement parameters PS and follow-up
parameters PI1, PI2, PI3 have been set, the textile machine 1 can start operating
to manufacture the textile product 5.
When the machine 1 and relevant control apparatus 80 are
activated, scanning means 94 belonging to controller 90 carries out sequential reading
of the main parameters 111 stored in each record 110 of memory 100; practically,
the scanning means 94 selects the records 110 one at a time following an orderly
succession, in such a manner that the parameters contained in each of them are employed
for regulating operation of the machine 1.
In other words, when a record 110 is selected by the scanning
means 94, the machine 1 performs a series of actuating steps of its members and/or
working steps of the textile product 5 depending on the parameters contained in
such a record 110; when reading and use of the parameters in such a record 110 has
been completed, the scanning means 94 select the following record for a correct
continuation of the machine operation.
In more detail, a first detecting block 96a carries out
reading within said record 110, of the first follow-up parameter PI1 contained therein;
a first transmission block 96b, connected with the first detecting block 96a and
with said sensor 13, sends the first follow-up parameter PI1 and the angular position
PA of the main shaft 12 to the activation device 32 of the first actuator 30.
The activation device 32 of the first actuator 30 is provided
with first comparator means 35 receiving the first follow-up parameter PI1 and the
angular position PA of the main shaft 12 and comparing these two magnitudes.
Depending on this comparison, the first comparator means
35 then sends a first control signal 131 to motor 31 to set the output shaft of
motor 31 in rotation with a follow-up ratio with respect to the main shaft 12 that
is defined by the first follow-up parameter PI1.
In addition to the above, the electric activation device
32 may comprise an auxiliary control block (not shown in the drawings) consisting
of an encoder associated with the output shaft 33 of motor 31, and of a regulation
circuit carrying out a feedback control on motor 31 depending on the information
about the position of the output shaft 33 detected by said encoder.
In a quite similar manner, reading of the other parameters
contained in said record 110 is carried out.
In fact, controller 90 comprises a second detecting block
97a to detect the second follow-up parameter PI2 belonging to record 110; a second
transmission block 97b connected with the second detecting block 97a and with sensor
13 sends the second follow-up parameter PI2 and the angular position PA of the main
shaft 12 to the activation device 52 of the second actuator 50.
The activation device 52 is provided with second comparator
means 55 that, depending on the comparison between the second follow-up parameter
PI2 and the angular position PA of the main shaft 12, transmits a second control
signal 132 to motor 51 so that the output shaft 53 of said motor 51 is set in rotation
with a follow-up ratio relative to the main shaft 12 that is defined by the second
follow-up parameter PI2.
The electric activation device 52 too can be provided with
en encoder and a regulation circuit connected therewith, to carry out a feedback
control on the position and rotation speed of the output shaft 53 of motor 51.
To enable reading of the third follow-up parameter PI3
contained in record 110, controller 90 further comprises a third detecting block
98a; also provided is a third transmission block 98b connected with the third detecting
block 98a and with sensor 13.
The third transmision block 98b sends the angular position
PA of the main shaft 12 and the third follow-up parameter PI3 to the activation
device 72 of the third actuator 70; the activation device 72 comprises third comparator
means 75 that, following a comparison between' the angular position PA of the main
shaft 12 and the third follow-up parameter PI3, transmits a third control signal
133 to motor 71.
In this way, the output shaft 73 of motor 71 is driven
in rotation with a follow-up ratio with respect to the main shaft 12 that is defined
by the third follow-up parameter PI3.
In the same manner as above described with reference to
the activation devices 32, 52 of the first and second actuators 30, 50, also the
activation device 72 of the third actuator 70 may comprise an encoder and a regulation
circuit operatively associated with motor 71 for a closed loop control of the position
and rotation speed of the output shaft 73 of the motor 71 itself.
It is apparent that, concurrently with the above described
operations, the sickle 6, frames 2, needle 8, knocking-over device 200 and compacting
reed 201 are suitably moved, in the manner as previously described.
The above description, as can be noticed, substantially
relates to a single record 110 and the weft row associated therewith; through a
subsequent scanning carried out by the scanning means 94 the following records are
then selected in succession.
It will be appreciated that, due to the technique for operation
and control of the above described machine 1, tensioning variations in the weft
yarn 19, warp yarns 18 and pulling of the textile product 5 can be obtained without
stopping operation of the machine 1, by merely sending appropriate command signals
to actuators 30, 50, 70.
In the light of the above, the control method of the textile
machine 1 is performed in a manner as described herebelow.
First of all, calculation of the first, second and third
follow-up parameters PI1, PI2, PI3 is carried out to define the follow-up ratio
between the output shafts 33, 53, 73 of the first, second and third actuators 30,
50, 70, and the main shaft 12.
This calculation occurs for each of the weft rows forming
the textile product 5 so that, at each individual movement of sickle 6 and of the
other weaving members, each actuator 30, 50, 70 receives a command signal 121, 122,
123 for movement, row by row, of the respective output shaft 33, 53, 73.
Advantageously, the first follow-up parameter PI1 is calculated
depending on the displacement parameters PS describing the displacements that are
carried out, in succession, by frames 2.
Before the follow-up parameters PI1, PI2, PI3 are transmitted
to the respective actuators, the angular position PA of the main shaft 12 is detected.
The first follow-up parameter PI1, together with the angular
position PA of the main shaft 12 is incorporated into a first command signal 121
that is transmitted to said comparator means 35 that, after comparing these magnitudes
with each other, generates a corresponding first control signal 131 for motor 31
of the first actuator 30.
The method further comprises a step of calculating the
second follow-up parameter PI2 for regulation of the second actuator 50; the second
follow-up parameter PI2 is calculated depending on appropriate data inputted by
the user and representative of the type of aesthetic effect or ornament that is
wished to be obtained in the fabric 5.
The second follow-up parameter PI2, together with the angular
position PA of the main shaft 12, is incorporated into a second command signal 122
that is sent to the activation device 52 of the second actuator 50.
The comparator means 55 of the activation device 52, upon
receiving the second command signal 122 and comparing the second follow-up parameter
PI2 with the angular position PA of the main shaft 12, sends a control signal to
motor' 51 so that the output shaft 53 of motor 51 is set in rotation with a follow-up
ratio defined by the second follow-up parameter PI2.
The method further comprises a step of calculating the
third follow-up parameter PI3; the third follow-up parameter PI3 is such calculated
as to be proportional to the density of stitches/centimetre of fabric inputted by
the operator.
In particular, this third follow-up parameter PI3 is obtained
as the product between a previously stored data, representative of the desired stitch
density (expressed in stitches/centimetre), and a conversion factor that allows
the obtained corresponding value to be transmitted to the third actuator 70, so
that movement of the take-down member 60 capable of determining the requested stitches/centimetre
density is obtained.
The third follow-up parameter PI3, together with the angular
position PA of the main shaft 12 is incorporated into a third command signal 123
that is transmitted to the electric activation device 72 of the third actuator 70.
The third comparator means 75, upon reception of the third
command signal 123, compares the angular position PA of the main shaft 12 and the
third follow-up parameter PI3 with each other and outputs a corresponding third
control signal 133 for motor 71, so that the output shaft 73 of said motor 71 is
driven in rotation with a follow-up ratio, with respect to the main shaft 12, defined
by the third follow-up parameter PI3.
While reference has been hitherto made to the textile machine
1 alone and the method of controlling it, the invention also extends to software
programs, in particular programs for computers, stored on a suitable medium to put
the invention into practice.
The program can be in the form of a source code, object
code, partly source code and partly object code, as well as in the form of partly
compiled formats, or any other form that can be employed to implement the method
of the present invention.
For example, the medium may comprise storage means such
as a ROM memory (a CD-ROM, a semiconductor ROM), a memory of the rewritable type
(e.g. flash EPROM) or magnetic storage means (floppy disks or hard disks, for example).
In addition, the medium may be a carrier set for transmission
such as an electric or optical signal that can be transmitted through electric or
optical cables or radio signals.
When the program is incorporated in a signal that can be
directly transmitted through a cable or device or equivalent means, the medium may
consist of such a cable, device or equivalent means.
Alternatively, the medium may be an integrated circuit
in which the program is incorporated, this integrated circuit being arranged to
carry out or employ said method in accordance with the present invention.
The invention achieves important advantages.
First of all, by adjusting the work speed of the first
feeding member, in particular depending on the width of movements of the frames,
a textile product can be obtained that has optimal aesthetic features, together
with ornamental effects in accordance with predetermined patterns.
Another advantage resides in that, by suitably combining
the variations in the rotation speeds of the first and second feeding members and
the take-down member, particular "special" effects can be obtained in the finished
product, that are for example due to alternating thinner portions with more compact
portions, to shrinkage and enlargement effects, etc.
Furthermore, the control carried out on machine 1 is very
precise due to precision and accuracy of all adjustments ensured by the above described
electronic control means.
In addition to the above, by virtue of the simplicity of
the operations to be performed for the machine setup, said operations can be carried
out by unqualified staff too.
Another advantage comes out with reference to the step
of studying new products or fabrics, during which several attempts are to be made
and the modalities of operation of the machine are to be correspondingly varied:
since these variations are obtained by merely operating on parameters inputted through
said electronic control means, very reduced times are required for obtaining the
desired product.
In addition, thanks to movement adjustment of the first
feeding member with which the warp yarns are in engagement, a precise feeding of
said warp yarns can be obtained even in the presence of important weight variations
in the beams around which such yarns are wound; said beams in fact have large sizes
and are arranged to bear big yarn amounts. Following a progressive unwinding of
the yarn itself, each beam can therefore have weight and inertia very different
from the starting ones and without said feeding member this fact would result in
a progressive but uncheckable variation in tensioning of the supplied warp yarn.
