Textile machine and control method thereof

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.