CN117622945A

CN117622945A - Method for controlled winding of textile product on textile machine and textile machine

Info

Publication number: CN117622945A
Application number: CN202311076679.8A
Authority: CN
Inventors: 托马斯·韦伯
Original assignee: Yokob Mueller Ltd Frick
Current assignee: Yokob Mueller Ltd Frick
Priority date: 2022-08-24
Filing date: 2023-08-23
Publication date: 2024-03-01
Also published as: EP4328365A1

Abstract

The present application relates to a method for controlled winding of textile products on a textile machine and to a textile machine. The warp threads (3) are unwound from the supply unit (2) and move longitudinally towards the thread interlacing area (8), in which area (8) the pulling roller (11) rotates to advance the textile product (9) towards the winding reel (15). The winding torque WT applied to the winding reel (15) is regulated by repeated winding adjustment cycles to maintain a target value WFtv of the winding traction provided to the textile product (9) downstream of the pulling roller (11). Each winding adjustment cycle includes: acquiring a winding rotational speed of the winding reel (15); acquiring the traction rotating speed of the traction roller (11); detecting an instantaneous winding diameter WD of the textile product (9) in the winding reel (15); and applying the instantaneous value of the winding torque WT calculated by the following formula: wt=wftv WD/2.

Description

Method for controlled winding of textile product on textile machine and textile machine

The present invention relates to a method for controlled winding of textile products on a textile machine, and a textile machine suitable for implementing the method.

The present invention can be conveniently applied to shuttle looms (weaving machines), such as rapier looms, air jet looms, water jet looms, shuttleless looms, narrow-band shuttle looms, etc., as well as knitting machines, etc., to simplify the construction and to improve the quality of the textile product collected on a winding reel (winding reel) by enhancing the tension control of the product.

In the present disclosure, "reel" means a drum, spool, cartridge (beam) or other type of cylindrical body carrying yarn or textile product wound in the form of a loop around a generally cylindrical core. "electric motor" means an induction electric motor, such as a Direct Current (DC) motor, an Alternating Current (AC) motor, or preferably a DC brushless motor.

Textile machines typically provide one or more supply units, such as supply reels, from which warp yarn (warp yarn) is transported towards a yarn interlacing area. In the yarn interlacing area, the yarn interlacing device forms a textile product by interlacing warp yarns supplied from the supply spool, possibly with the insertion of weft yarns and/or other yarns, depending on the type of machine and/or the desired textile pattern.

A pulling drive system including a pulling roller operates on the textile product at or immediately downstream of the yarn interlacing area to pull warp yarns from the supply spool and move the textile product away from the yarn interlacing area. Downstream of the yarn interlacing area, the textile product is collected by winding into a superimposed coil (superposed coil) on a winding reel.

The tension of the textile product reaching the winding reel is a critical parameter for obtaining good quality of the final product. For example, poor tension during loose winding may result in wrinkling or other imperfections of the textile product and a reduction in the amount of textile product for a given spool diameter. Likewise, excessive tension can result in excessive stretching, resulting in structural defects and permanent damage to the wound textile product.

Currently, attempts have been made to control the tension by driving the rotation of the winding reel by a mechanical transmission of motion from a traction drive system. The known arrangement provides a mechanical clutch that operates along the mechanical transmission and is equipped with an adjustable torque drive system. The adjustable torque drive system accommodates the torque applied to the take-up spool to maintain a desired tension along the textile product extending between the pull roller and the take-up spool. Typically, the adjustable torque drive system operates in response to a winding pull force value that is monitored by a tension roller acting on the textile product between the pull roller and the winding spool.

However, the known arrangements as disclosed above do not meet the increasing demands in terms of quality and reproducibility of the finished product, since the actual tension applied to the textile product varies significantly with respect to the desired value.

The known arrangements also require the installation of sensors and/or mechanisms to detect the applied tension and/or when the winding reel is full and needs replacement. In fact, two force sensors are typically required for each side of the scroll wheel, along with associated electronics, thus increasing cost.

Furthermore, the known system does not easily obtain reliable monitoring of the instant diameter of the winding reel when needed, for example in time awareness of the need for replacement.

The scope of the present invention is to improve the prior art, in particular by providing a method and apparatus whereby an accurate control of the tension of the textile product leaving the pulling roller is achieved.

A further object of the invention is to allow improved control of the tension of the warp yarns leading to the pulling roller.

An additional object of the present invention is to allow the precise control specified above to be achieved by a simplified and inexpensive system that does not necessarily require additional sensors.

According to the present invention, it has been found that by monitoring the rotational speed on the winding reel and/or supply unit relative to the rotational speed of the pulling roller, and in response to a change in the ratio between these rotational speeds, an improved tension control of the textile product and/or warp yarn downstream and upstream of the pulling roller, respectively, can be achieved by increasing or decreasing the torque applied by the motor on the winding reel and/or supply unit.

More particularly, the invention relates to a method for controlled winding of textile products on a textile machine, wherein: the warp yarn is unwound from the supply unit and moves longitudinally to reach the yarn interlacing area; a textile product comprising said warp yarns is formed at the yarn interlacing area; a pulling roller having an outer diameter engages the textile product proximate the yarn interlacing area and rotates at a pulling rotational speed n11 to advance the textile product toward at least one take-up spool.

Preferably, the winding reel rotates about a winding rotation axis to wind the textile product into respective superimposed coils, each coil being wound according to an instantaneous winding diameter WD; a winding torque WT is applied to the winding reel for providing a winding traction WF on the textile product between the pulling roller and the winding reel.

The method further comprises the steps of: adjusting the winding torque WT to maintain the winding traction WF at a desired target value WFtv, wherein adjusting the winding torque WT comprises repeated winding adjustment cycles, each winding adjustment cycle comprising: acquiring a winding rotation speed n15 of the winding reel; acquiring the traction rotating speed n11 of the traction roller; detecting the instant wrapping diameter WD; and applying the instantaneous value of the winding torque WT calculated by the following formula:

WT＝WFtv*WD/2。

in another aspect, the invention relates to a textile machine comprising: at least one supply unit configured to carry warp yarns; yarn interlacing means acting at the yarn interlacing area for producing a textile product from warp yarns supplied from the supply unit; a pulling roller having an outer diameter and configured to engage the textile product proximate the yarn interlacing area and advance the textile product away from the yarn interlacing area; a winding reel configured to receive the textile product advanced via the pulling roller and wind the textile product into respective overlapping loops, each of which is wound according to an instantaneous winding diameter.

A winding motor is preferably provided. The winding motor is configured to apply a winding torque to the winding spool, thereby applying a winding traction on the textile product between the pulling roller and the winding spool.

A detector acts on the winding reel for detecting the instantaneous winding diameter on the textile product wound on the winding reel. The detector can be conveniently applied without the need for sensors and associated additional hardware. For example, in a preferred embodiment, the detector comprises a central processing unit configured to receive an input signal representative of the instantaneous winding diameter and to act on the winding motor for adjusting the winding torque according to the instantaneous winding diameter to maintain the winding tractive effort at a predetermined target value.

It should be noted that the rotational speed n11 of the pulling roller is always known, for example given by the input control of the motor of the pulling roller, while the winding rotational speed n15 is gradually reduced during the production process. The ratio n11/n15 between the rotational speeds in the algorithm for determining the instant winding torque value is thus proportional to the instant value of the winding diameter of the textile product on the winding reel. Thus, any change in the winding diameter that gradually increases as the textile product is collected on the winding reel during the manufacturing process causes a corresponding increase in the instant winding torque value applied to the winding reel. Thus, the adjustment achieved according to the invention allows an improved control of the winding traction exerted on the textile product at each stage of the production process, irrespective of any variation of the winding diameter on the winding reel.

In particular, the torque and rotational speed values on the single drawing roller and the winding reel and, if necessary, on the supply unit can be directly derived as input and/or output data from the electronic control unit implementing the respective electric motor. Thus, the present invention can be practiced without the need to install an additional sensor system on the textile machine.

The winding force control achieved by the invention adapts itself in time to the actual rotational speed n11 of the pulling roller. The rotational speed n11 of the pulling roller can then be freely controlled to vary according to any desired weaving plan or pattern without affecting the efficiency of the winding force control.

It should also be noted that the winding speed n15 is proportional to the instantaneous winding diameter and the speed n2 of the supply unit is proportional to the instantaneous diameter of the supply unit. The invention thus allows to easily monitor the diameter of the winding reel and if necessary the supply unit, for example when the winding reel or (if necessary) the supply unit will be full or empty, respectively, providing a replacement warning signal without the need for additional sensor means.

In at least one preferred embodiment, the present invention may also include one or more of the following preferred features.

Preferably, the detection of the instant winding diameter WD is calculated, in one or more of said winding adjustment cycles, by the following formula:

WD＝DD*n11/n15。

preferably, the winding motor is started by a winding supply current I17 calculated according to the following formula:

I17＝WT/kT17

where kT17 denotes the current constant of the winding motor.

As is well known, this current constant is a motor specific value, typically expressed in Nm/a units.

Preferably, the instantaneous value of the winding torque WT is applied to the winding reel via a winding gearbox reducer that connects the winding motor to the winding reel according to a winding gear ratio i 18.

I17＝WT/(kT17*i18)

where kT17 denotes the current constant of the winding motor.

The efficiency of the winding gearbox reducer can be introduced as an additional factor in the formula when higher accuracy is required.

Preferably, the repetition of the winding adjustment cycle occurs at a desired frequency.

Preferably, the desired frequency is comprised between 1Hz and 10 Hz.

Preferably, the desired frequency is kept constant.

Preferably, the desired frequency is gradually varied during operation of the machine.

Preferably, at least one winding adjustment cycle is effected for each rotation of the winding reel about the winding rotation axis. The number of these adjustment cycles can be increased if desired, for example up to five cycles for each rotation of the winding reel, to calculate a more reliable average.

Preferably, the controlled variation of the target value WFtv of the winding traction WF occurs during the operation of the textile machine.

Preferably, the winding traction WF gradually decreases as the winding diameter WD increases, or vice versa.

According to a different aspect of the invention, the supply unit rotates about a unwinding rotation axis to unwind the warp yarn moving towards the yarn interlacing area; a supply torque ST is applied to the supply unit for providing a supply traction force SF on the warp yarn between the pulling roller and the supply unit; and effecting control of the supply traction force SF during operation of the textile machine to maintain it at a desired target value SFtv.

Preferably, the control of the supply traction force SF is achieved by adjusting the supply rotational speed n2 of the supply unit to maintain the supply traction force SF at the target value SFtv.

Preferably, adjusting the supply rotational speed n2 comprises repeating supply adjustment cycles, each supply adjustment cycle comprising:

obtaining a traction supply current I12 of a traction motor;

calculating a pulling torque DT applied to the pulling roller based on the pulling supply current I12;

the instantaneous value of the supply traction SF is calculated by the following formula:

SF＝DT*2/DD

comparing the instantaneous value of the supply traction force SF with the target value SFtv;

increasing the supply rotational speed n2 when SF > SFtv;

when SF < SFtv, the supply rotational speed n2 is reduced.

For greater precision, the formula for calculating the instantaneous value of the supply traction SF can be modified taking into account the winding traction WF, as follows:

SF＝DT*2/DD+WF。

however, WF may actually be ignored because it is typically much lower than SF.

Preferably, the pulling torque DT is calculated by the following formula:

DT＝I12*kT2

where kT2 represents the current constant of the traction motor.

Preferably, the pulling torque DT is applied to the pulling roller via a pulling gearbox reducer that connects the pulling motor to the pulling roller according to a pulling gear ratio i 13.

Preferably, the pulling torque DT is calculated by the following formula:

DT＝I12*kT2*i13

where kT2 represents the current constant of the traction motor.

The efficiency of the traction gearbox reducer can be introduced as an additional factor in the formula when higher accuracy is required.

Preferably, the control of the supply traction force SF is achieved by adjusting the supply torque ST to maintain the supply traction force SF at a desired target value SFtv.

Preferably, adjusting the supply torque ST comprises repeated supply adjustment cycles, each supply adjustment cycle comprising:

acquiring a supply rotating speed n2 of the supply unit;

acquiring the traction rotating speed n11 of the traction roller; and

a supply torque target value STtv calculated by the following formula is applied to the supply unit:

STtv＝SFtv x UD/2。

where UD denotes the instant unwind diameter UD on the supply unit.

Preferably, the central processing unit is configured to calculate the instant unwind diameter UD on the supply unit based on the supply rotational speed n2 of the supply unit and the pulling rotational speed n11 of the pulling roller, according to the following formula:

UD＝DD*n11/n2。

acquiring a supply rotating speed n2 of the supply unit;

acquiring the traction rotating speed n11 of the traction roller; and

STtv＝SFtv*0.5*DD*n11/n2。

preferably, repeating the supply adjustment cycle occurs at a desired frequency.

Preferably, said desired frequency of adjustment cycles for this supply is comprised between 1Hz and 10 Hz.

Preferably, the desired frequency is kept constant.

Preferably, the desired frequency is gradually varied during operation of the textile machine.

Preferably, at least one supply adjustment cycle is implemented for each rotation of the supply unit about the unwinding rotation axis.

The number of adjustment cycles can be increased, if desired, for example up to five cycles per rotation of the supply unit, to calculate a more reliable average.

Preferably, a controlled variation of the target value SFtv of the supply traction SF occurs during operation of the textile machine.

Preferably, the detector comprises a winding electronic control unit equipped with the winding motor and configured for detecting the rotation speed n17 of the winding motor.

Preferably, a winding gearbox reducer operating between the winding motor and the winding reel is provided, and a winding controller configured to receive the rotation speed n17 detected by the winding electronic control unit and to calculate the winding rotation speed n15 of the winding reel according to formula n15=n17×i18 based on the gear ratio i18 of the winding gearbox reducer.

Preferably, a traction electronic control unit is provided, which is equipped with a traction motor of the traction roller and is configured for detecting the rotational speed n12 of the traction motor.

Preferably, a traction gearbox reducer operating between the traction motor and the traction roller is provided, and a traction controller configured to receive the rotation speed n12 detected by the traction electronic control unit and calculate a traction rotation speed of the traction roller according to formula n11=n12×i13 based on a transmission ratio i13 of the traction gearbox reducer.

Preferably, the central processing unit is configured to calculate the instant winding diameter WD according to the following formula based on the winding rotation speed n15 of the winding reel and the pulling rotation speed n11 of the pulling roller:

WD＝DD*n11/n15

according to a further different aspect, a unwinding drive unit is preferably provided, which is configured to apply a supply torque opposite to the rotation of the supply unit about the unwinding rotation axis, thereby providing a supply traction force SF on the warp yarn between the pulling roller and the supply unit.

Preferably, a traction electronic control unit is provided, which is equipped with a traction motor of the traction roller and is configured to acquire a traction supply current I12 of the traction motor.

Preferably, a pulling controller is provided which is configured to calculate the pulling torque DT applied to the pulling roller from the pulling supply current I12.

Preferably, the central processing unit is further configured to calculate the supply traction SF by the formula:

SF＝DT*2/DD+WF

preferably, a comparator is provided, which is configured to compare the supply traction force SF with the target value SFtv.

Preferably, the central processing unit is further configured to:

increasing the supply rotational speed n2 when SF > SFtv;

when SF < SFtv, the supply rotational speed n2 is reduced.

Preferably, a pull controller is provided, configured to receive the pull supply current I12 detected by the pull electronic control unit and to calculate the pull torque DT according to the following formula:

T2＝I12*kT12

where kT12 represents the current constant of the traction motor.

Preferably, a traction gearbox reducer operating between the traction motor and the traction roller is provided, and a traction controller configured to receive the traction supply current I12 detected by the traction electronic control unit and calculate the traction torque DT according to the following formula based on a gear ratio I13 of the traction gearbox reducer:

T2＝I12*kT12/i13

where kT12 represents the current constant of the traction motor.

According to a different aspect, it is preferable to provide that:

a unwinding electronic control unit equipped with a unwinding motor of the supply unit and configured to obtain a supply rotation speed n2 of the supply unit;

a pulling electronic control unit equipped with the pulling motor and configured to acquire a pulling rotational speed n11 of the pulling roller 11;

wherein the central processing unit is configured to receive input signals representative of the supply rotational speed n2 and the pulling rotational speed n11 and to calculate a supply torque target value STtv applied to the supply unit 2 by the following formula:

STtv＝SFtv x UD/2

where UD denotes the instant unwind diameter on the supply unit.

Preferably, the central processing unit is configured to calculate the instant unwind diameter UD on the supply unit according to the following formula based on the supply rotational speed n2 of the supply unit and the pulling rotational speed n11 of the pulling roller:

UD＝DD*n11/n2。

acquiring a supply rotating speed n2 of the supply unit;

acquiring the pulling rotation speed n11 of the pulling roller 11; and

STtv＝SFtv*0.5*DD*n11/n2。

preferably, the unwind motor is configured to apply a supply torque ST to the supply unit, thereby applying a supply traction SF to warp yarn between the supply unit and the pulling roller.

Preferably, a unwind electronic control unit is provided, equipped with the unwind motor and configured to detect the rotation speed n5 of the unwind motor.

Preferably, a unwind gearbox reducer operating between the unwind motor and the supply unit is provided, and an unwind controller configured to receive the rotation speed n5 detected by the unwind electronic control unit and to calculate the supply rotation speed n2 of the supply unit 2 according to the formula n2=n5×i6 based on the gear ratio i6 of the unwind gearbox reducer.

Drawings

Additional features and advantages will be made clearer by the detailed description of a method for controlled winding of a textile product on a textile machine according to the invention, and of a preferred but not exclusive embodiment of a textile machine suitable for implementing this method. The description will be presented below with reference to a set of drawings provided as non-limiting examples only, in which:

FIG. 1 schematically shows a side cross-sectional view of an exemplary textile machine equipped with a control system for implementing the method according to the invention;

FIG. 2 is a logic flow diagram of the operation of the textile machine implementing the winding control method according to the present invention;

fig. 3 is a logic flow diagram of the operation of the textile machine implementing supply traction control upstream of the traction drive system in the textile machine.

In fig. 1, a textile machine is indicated generally by the representative symbol 1. The textile machine 1 may be, for example, a rapier loom, an air jet loom, a water jet loom, a shuttle loom, a narrow-band shuttle loom, a knitting machine or other types of textile machines 1.

The textile machine 1 comprises at least one supply unit 2, for example in the form of at least one supply spool or roller. When the supply unit 2 rotates about the respective unwinding rotation axis X2 under the action of the unwinding drive unit 4, a plurality of warp yarns 3 unwind from the supply unit 2. In an alternative possible solution, not shown in the figures, the supply unit 2, rotated under the control of the unwinding drive unit 4, can be configured to unwind the warp yarns 3 from respective bobbins carried by one or more creels.

The unwind drive unit 4 comprises an unwind motor 5, preferably connected to the supply unit 2 via an unwind gearbox reducer 6. The unwind motor 5 is conveniently controlled by an unwind electronic control unit 7, the unwind electronic control unit 7 being able to control the rotational speed, the supply current, and/or other operating parameters of the unwind motor 5. More specifically, a brushless-type motor equipped with the unwinding electronic control unit 7 can be conveniently used as the unwinding motor 5.

The warp yarns 3 stretched from the supply unit 2 move longitudinally to a yarn interlacing area 8 (e.g. a tatting area or a knitting area), wherein a yarn interlacing device (not shown) operates to produce a textile product 9 from the warp yarns 3 supplied by the supply unit 2. For this purpose, these warp yarns 3 may be connected to each other and/or to one or more weft yarns and/or other additional yarns in any known manner not disclosed herein as forming part of the present invention. These yarn interlacing means may typically comprise or consist of a yarn guiding element cooperating with the oscillating member: the yarn guiding elements are also not shown in the drawings, as they may be implemented in many different known ways, as desired.

A pulling unit 10 engages the textile product 9 in the vicinity of the yarn interlacing area 8, i.e. at or immediately downstream of the yarn interlacing area 8. The drawing unit 10 comprises a drawing roller 11 which acts on the textile product 9 to advance it away from the yarn interlacing area 8. The pulling roller 11 also produces a pulling action on the warp yarns 3 from the supply unit 2. In fig. 1 DD indicates the drawing diameter defined by the drawing roller 11, acting on the textile product 9 at the outer surface of the drawing roller. A pulling motor 12 is preferably connected to the pulling roller 11 via a pulling gearbox reducer 13 to rotate the pulling roller 11 at a controlled angular speed and torque. The traction motor 12 is conveniently controlled by a respective traction electronic control unit 14, the traction electronic control unit 14 being able to control the rotation speed, the supply current and/or other operating parameters of the traction motor 12. A brushless type motor equipped with the traction electronic control unit 14 can be conveniently used as the traction motor 12.

The textile product 9 moving from the yarn interlacing area 8 advances towards a winding reel 15, the winding reel 15 being configured to receive the textile product 9.

The winding unit 16 operates on the winding reel 15 to rotate the winding reel 15 about the winding rotation axis X15. The winding unit 16 also applies a winding torque WT to the winding reel 15, thereby applying a winding traction WF to the textile product 9 along an stretch (stretch) of the textile product 9 extending between the pulling unit 10 and the winding reel 15.

The winding unit 16 comprises a winding motor 17, the winding motor 17 being connected to the winding reel 15 preferably via a winding gearbox reducer 18. The winding motor 17 is conveniently controlled by a winding electronic control unit 19, the winding electronic control unit 19 being able to control the rotational speed, the supply current, and/or other operating parameters of the winding motor 17. More specifically, a brushless-type motor equipped with the winding electronic control unit 19 can be conveniently used as the winding motor 17.

Rotation of the winding reel 15 causes the textile product 9 to be wound about the winding rotation axis X15 into respective superimposed coils 9a, each coil 9a being wound according to a winding diameter WD. The thickness of the textile product 9 is such that the winding diameter WD is different for each coil 9 a. In fact, once each coil 9a is formed around the winding rotation axis X15 of the winding reel 15, the winding diameter WD gradually increases.

If the winding torque WT exerted by the winding unit 16 on the winding reel 15 is kept constant, any variation of the winding diameter WD will affect the value of the winding traction WF. However, the present invention provides for gradually adjusting, i.e. adjusting, the winding torque WT while the textile product 9 is being formed and wound on the winding reel 15 to maintain the winding traction WF at a desired target value WFtv. The desired target value WFtv of the winding traction WF can be set conveniently by the user, or selected by a stored program library, or provided by a work plan. If desired, the target value WFtv of the winding traction WF may be varied during the execution of the job according to the established work schedule, for example, increased and/or decreased with a gradual increase of the winding diameter WD.

At least one detector 19, 20 acts on the winding reel 15 for detecting at any instant in time the instant winding diameter WD of the textile product 9 wound on the winding reel 15 or a representative parameter thereof. In a preferred embodiment, the detector comprises the winding electronic control unit 19 equipped with the winding motor 17. In fact, the winding electronic control unit 19 is able to detect the rotation speed n17 of the winding motor 17, i.e. the rotation speed n17 of its rotor, at any moment, as is generally the case in the control systems of brushless motors. The winding controller 20 receives the rotational speed n17 as an input signal to calculate the winding rotational speed n15 of the winding reel 15 based on the value of the winding gear ratio i18 of the winding gear box reducer 18 according to the following formula:

n15＝n17*i18。

the winding controller 20 may be embedded in the winding electronic control unit 19 or separate therefrom, for example as part of a central processing unit CPU that monitors the operation of the entire textile machine 1 or related parts thereof as shown in fig. 1.

In a similar manner, the traction control electronics 14 can detect the rotational speed n12 of the traction motor 12, i.e. the rotational speed n12 of its rotor, at any time. The rotation speed n12 is received as an input signal by a traction controller 21, which traction controller 21 is for example embedded in the traction electronic control unit 14 or separate therefrom, for example as part of the central processing unit CPU, to calculate the traction rotation speed n11 of the traction roller 11 based on the value of the traction transmission ratio i13 of the respective traction gearbox reducer 13 by the formula n11=n12×i13.

The pull controller 21 may be embedded within the pull electronic control unit 14 or separate therefrom, for example as part of the central processing unit CPU.

With particular reference to fig. 2, the adjustment of the winding traction WF is obtained according to the following method. The method may be implemented by the central processing unit CPU or other parts of the textile machine 1, which may be programmed or configured to control the winding of the textile product 9 in the following way.

At start-up of the textile machine 1 (block 22), the target value WFtv of the winding traction WF is set, for example, by the user via an input interface or by selection from a stored function table (block 23). The selection may be part of a stored work plan.

As can be derived from block 24 in fig. 2, the winding speed n15 (sub-block 24 a) and the pulling speed n11 (sub-block 24 b) are acquired, for example, as disclosed above, derived from data detected by the winding electronic control unit 19 and the pulling electronic control unit 14, respectively.

Based on the obtained values of speeds n11 and n15, the instant wrapping diameter WD is also detected (block 25). More specifically, the instant wrapping diameter WD is conveniently calculated by the following formula:

WD＝DD*n11/n15。

in fact, since no significant sliding/stretching of the textile product 9 takes place on the external surfaces of the drawing roller 11 and of the winding reel 15, the ratio WD/DD between the diameters is equal to the ratio n11/n15 between the rotational speeds.

Based on the detected value of the immediate winding diameter WD, an immediate value of the winding torque WT suitable for achieving the previously set target value of the winding traction WFtv is then calculated (block 26). More specifically, the instantaneous value of the winding torque WT is calculated by the following formula:

WT＝WFtv*WD/2。

the obtained instant value of the winding torque WT is then applied to the winding reel 15 via the winding motor 17 and the corresponding winding gearbox reducer 18 (block 27). For example, the achievement of the desired instantaneous value of the winding torque WT can be obtained by starting the winding motor 17 with a winding supply current I17 calculated according to the following formula, according to the command of the winding electronic control unit 19:

I17＝WT/(kT17*i18)

where kT17 denotes the current constant, i.e. the specific (near) constant value of the winding motor 17.

During operation of the textile machine 1, the above-described winding adjustment cycle is repeated, so that the instantaneous value of the winding torque WT can be updated in time during the gradual increase of the winding diameter WD, in order to maintain the desired target value WFtv of the winding traction WF.

Repetition of the winding adjustment cycle may occur at a desired frequency, preferably comprised between 1Hz and 10 Hz. The frequency may remain constant or vary gradually during operation of the machine, for example achieving a fixed number, preferably at least 1 winding adjustment cycle, for each revolution effected by the winding reel 15 about the winding rotation axis X15.

Any controlled variation of the target value WFtv of the winding traction WF can also be achieved if desired during the operation of the textile machine 1, for example according to a pre-established work plan. For example, depending on the production specifications, when the winding diameter WD is relatively small, a larger winding traction WF may be set for the first coil 9a on the winding reel 15 to gradually decrease the winding traction WF as the winding diameter WD increases, or vice versa.

During operation of the textile machine 1, the supply unit 2 rotates about the unwinding axis of rotation X2 to unwind the warp yarn 3 moving towards the yarn interlacing area 8.

The unwind motor 5 and the unwind gearbox reducer 6 apply a supply torque ST to the supply unit 2. Preferably, the supply torque ST resists the rotation experienced by the supply unit 2 when it acts on the warp yarn 3 through the pulling unit 10, however does not hinder the rotation required to unwind the warp yarn 3. Thus, the supply traction force SF is maintained along the warp yarn 3 extending between the supply unit 2 and the pulling roller 11.

The effective control of the supply traction force SF is critical for the correct execution of the interconnection of warp yarns 3 with each other and/or with weft yarns and/or other yarns at the yarn interlacing area 8.

At least when the supply unit 2 is in the form of a reel carrying warp yarn 3 wound around the unwinding rotation axis X2, the rotation of the supply unit 2 causes its outer diameter (hereinafter also referred to as unwinding diameter UD) to gradually decrease as the warp yarn 3 is unwound from the unwinding reel 15. Thus, if the supply torque ST is kept constant, the supply traction SF will gradually increase in response to a gradual decrease of the unwinding diameter UD during operation of the textile machine 1. However, according to a different and independent aspect of the invention, positive control of the supply traction force SF is preferably implemented to maintain the supply traction force SF at a desired target value SFtv.

As shown in fig. 3, the desired target value SFtv of the supply traction SF may be conveniently set by a user (see block 28 in fig. 3), or provided by a work plan at the start 22 of the textile machine 1 or immediately after the start 22 of the textile machine 1. If desired, the target value SFtv of the supply traction SF may be varied during operation of the textile machine 1 according to a pre-established program, for example increasing and/or decreasing with the progress of the work in response to a change in the knitting pattern performed in the yarn interlacing area 8. In fact, for example, the pre-established knitting pattern may comprise a production phase (production stage) in which the supply traction SF needs to be greater or less than the previous or subsequent production phase, for example due to the insertion of additional yarns in the yarn interlacing area 8 or for other reasons, in order to optimize the result.

In a preferred embodiment, the control of the supply traction force SF is achieved by adjusting the supply rotational speed n2 of the supply unit 2 to maintain the supply traction force SF at the target value SFtv. In practice, the central processing unit CPU may be configured to implement repeated supply adjustment cycles, each supply adjustment cycle comprising calculating the instantaneous value of the supply traction force SF based on the traction torque DT applied to the traction roller 11. The pull torque DT may be calculated by the pull controller 21 as a function of the pull supply current I12 of the pull motor 12. The pull-supply current I12 may be obtained by the pull-electronic control unit 14 (block 29). Next (block 30), the tractive torque DT may be calculated by the following equation:

DT＝I12*kT12*i13

where kT12 represents the current constant of the traction motor 12.

Preferably, the instantaneous value of the supply traction SF is then calculated according to the following formula (block 31):

SF＝DT*2/DD+WF

it also takes into account the effect of the winding traction WF applied to the textile product 9.

A comparator (not shown), for example embedded in the central processing unit CPU or separate therefrom, may be provided for comparing the instantaneous value of the supply traction force SF with its target value SFtv. If the instantaneous value of the supply tractive effort SF is equal to the target value SFtv (block 32), a new supply adjustment cycle is implemented.

Otherwise (block 33), the comparator determines if the immediate supply tractive effort SF is less than the target value SFtv. If so, the central processing unit CPU drives the unwind motor 5 to increase the supply rotational speed n2 (block 34). Otherwise, the supply rotational speed n2 is reduced (block 35).

The increase and decrease of the rotation speed n2 respectively cause the supply traction SF to decrease and increase toward the target value SFtv, respectively.

Any adjustment of this supply rotational speed n2 triggers a new supply adjustment cycle as shown in fig. 3. The repetition of this supply adjustment cycle may occur at a desired frequency, preferably comprised between 1Hz and 10 Hz. During operation of the machine, the frequency may be kept constant or gradually varied, for example to achieve a predetermined number, preferably at least one supply adjustment cycle for each rotation achieved by the supply unit 2 about the rotation axis X2.

In a possible alternative embodiment, the control of the supply traction force SF may be achieved by adjusting the supply torque ST instead of the supply rotational speed n2 to maintain the supply traction force SF at the desired target value SFtv. In this example, each supply adjustment cycle would include taking the pulling rotational speed n11 of the pulling roller 11 and taking the supply rotational speed n2 of the supply unit 2. These acquisition steps can be implemented by the pulling controller 21 and the unwinding controller 36, respectively. The unwind controller 36 receives as input signal the rotational speed n5 of the unwind motor 5, i.e. the rotational speed n5 of its rotor, and may be configured to calculate the supply rotational speed n2 of the supply unit 2 based on the gear ratio i6 of the unwind gearbox reducer 6 according to the following formula:

n2＝n5*i6。

the unwind controller 36 may be embedded within the unwind electronic control unit 7 or separate therefrom, e.g. as part of the central processing unit CPU. The central processing unit CPU may be configured to receive input signals representative of the acquired values and command the unwind motor 5 to apply to the supply unit 2 a target torque value STtv calculated by the following formula:

STtv＝SFtv*0.5*DD*n11/n2。

additionally or alternatively, the central processing unit CPU may be configured to calculate the instant unwind diameter UD on the supply unit 2 based on the supply rotational speed n2 and the pulling rotational speed n11 of the pulling roller 11 according to the following formula:

UD＝DD*n11/n2。

the target torque value STtv may be calculated accordingly by the following formula:

STtv＝SFtv x UD/2。

Claims

1. a method for controlled winding of a textile product (9) on a textile machine, wherein:

the warp threads (3) are unwound from the supply unit (2) and move longitudinally to reach the thread interlacing area (8);

a textile product (9) comprising said warp yarns (3) is formed at said yarn interlacing area (8);

a pulling roller (11) having an outer diameter DD is engaged with the textile product (9) close to the yarn interlacing area (8) and rotates at a pulling rotational speed n11 to advance the textile product (9) towards at least one winding reel (15);

the winding reel (15) rotates on a winding rotation axis (X15) to wind the textile product (9) into respective superimposed coils (9 a), each coil being wound according to an instantaneous winding diameter WD;

a winding torque WT is applied to the winding reel (15) for providing a winding traction WF on the textile product (9) between the pulling roller (11) and the winding reel (15);

the method further comprises:

the winding torque WT is adjusted to maintain the winding traction WF at a desired target value WFtv,

wherein adjusting the winding torque WT comprises repeated winding adjustment cycles, each winding adjustment cycle comprising:

acquiring a winding rotation speed n15 of the winding reel (15);

acquiring the pulling rotation speed n11 of the pulling roller (11);

detecting the instant wrapping diameter WD; and

applying an instantaneous value of said winding torque WT calculated by the following formula:

WT＝WFtv*WD/2。

2. the method of claim 1, wherein during one or more of the wrap adjustment cycles, detecting the instant wrap diameter WD is performed by calculating the instant wrap diameter WD by:

WD＝DD*n11/n15。

3. the method of claim 1 or 2, wherein repetition of the winding adjustment cycle occurs at a frequency comprised between 1Hz and 10 Hz.

4. The method according to one or more of the preceding claims, wherein for each rotation of the winding reel (15) about the winding rotation axis (X15) at least one winding adjustment cycle is achieved.

5. Method according to one or more of the preceding claims, wherein a controlled variation of the target value WFtv of the winding traction WF occurs during the operation of the textile machine (1).

6. The method according to one or more of the preceding claims, wherein:

as the wrap diameter WD increases, the wrap traction WF gradually decreases, or

As the wrap diameter WD decreases, the wrap traction WF gradually increases.

7. The method according to one or more of the preceding claims, wherein:

-the supply unit (2) rotates on a unwinding rotation axis (X2) to unwind the warp yarn (3) moving towards the yarn interlacing area (8);

a supply torque ST is applied to the supply unit (2) for providing a supply traction SF on the warp yarn (3) between the pulling roller (11) and the supply unit (2); and

control of the supply traction force SF is effected during operation of the textile machine (1) to maintain the supply traction force SF at a desired target value SFtv.

8. Method according to claim 7, wherein the control of the supply traction SF is achieved by adjusting the supply rotational speed n2 of the supply unit (2) to keep the supply traction SF at the target value SFtv.

9. The method of claim 8, wherein adjusting the supply rotational speed n2 comprises repeating supply adjustment cycles, each supply adjustment cycle comprising:

acquiring a traction supply current I12 of a traction motor (12);

calculating a pulling torque DT applied to the pulling roller (11) from the pulling supply current I12;

SF＝DT*2/DD；

comparing said instantaneous value of said supply traction force SF with said target value SFtv;

increasing said supply rotational speed n2 when SF > SFtv;

when SF < SFtv, the supply rotational speed n2 is reduced.

10. Method according to one or more of claims 7 to 9, wherein a controlled variation of the target value SFtv of the supply traction SF occurs during operation of the textile machine (1).

11. A textile machine, comprising:

at least one supply unit (2) configured to carry warp yarns (3);

yarn interlacing means acting at a yarn interlacing area (8) for producing a textile product (9) from the warp yarns (3) supplied from the supply unit (2);

-a pulling roller (11) having an outer diameter DD configured to engage the textile product (9) close to the yarn interlacing area (8) and advance the textile product away from the yarn interlacing area (8);

a winding reel (15) configured to receive the textile product (9) advancing via the pulling roller (11) and to wind the textile product into respective superimposed loops (9 a), each winding according to an instantaneous winding diameter WD;

a winding motor (17) configured to apply a winding torque WT to the winding reel (15), thereby applying a winding traction WF on the textile product (9) interposed between the pulling roller (11) and the winding reel (15);

-a detector acting on the winding reel (15) for detecting the instantaneous winding diameter WD of the textile product (9) wound on the winding reel (15);

wherein the detector comprises a Central Processing Unit (CPU) configured to receive an input signal representative of the instantaneous winding diameter WD and to act on the winding motor (17) for adjusting the winding torque WT according to the instantaneous winding diameter WD so as to maintain the winding traction WF at a predetermined target value WFtv.

12. Textile machine according to claim 11, wherein the Central Processing Unit (CPU) is configured to calculate the instantaneous winding diameter WD based on a winding rotation speed n15 of the winding reel (15) and a pulling rotation speed n11 of the pulling roller (11), according to the following formula:

WD＝DD*n11/n15。

13. the textile machine according to claim 11 or 12, further comprising a unwinding drive unit (4) configured to apply a supply torque opposite to the rotation of the supply unit (2) about a unwinding rotation axis (X2), thereby providing a supply traction SF on the warp yarn (3) between the pulling roller (11) and the supply unit (2).

14. The textile machine of claim 13, further comprising:

a traction electronic control unit (14) equipped with a traction motor (12) of the traction roller (11) and configured to acquire a traction supply current I12 of the traction motor (12);

-a traction controller (21) configured to calculate a traction torque DT applied to the traction roller (11) from the traction supply current I12;

wherein the Central Processing Unit (CPU) is further configured to calculate the supply tractive effort SF by the formula:

SF＝DT*2/DD。

15. the textile machine according to claim 13 or 14, further comprising a comparator configured to compare the supply tractive effort SF with a target value SFtv of the supply tractive effort SF, wherein the Central Processing Unit (CPU) is further configured to:

increasing said supply rotational speed n2 when SF > SFtv;

when SF < SFtv, the supply rotational speed n2 is reduced.