EP3792209A1

EP3792209A1 - Apparatus for feeding yarn from a plurality of stacks of yarn feeders to a textile machine

Info

Publication number: EP3792209A1
Application number: EP20191396.9A
Authority: EP
Inventors: Pietro Zenoni; Agostino Facotti
Original assignee: LGL Electronics SpA
Current assignee: LGL Electronics SpA
Priority date: 2019-09-16
Filing date: 2020-08-17
Publication date: 2021-03-17
Anticipated expiration: 2040-08-17
Also published as: EP3792209B1; CN112501773A; IT201900016340A1

Abstract

An apparatus comprising at least one stack of feeders (F1, F2, F3), each of which is provided with a motorized yarn winding reel (12) adapted to draw the yarn from a spool in order to feed it to a textile machine. The feeders (F1, F2, F3) are all connected electronically on a primary communication channel (32) in order to communicate bidirectionally with a central control unit (CU), are provided with electronic interconnection means (RXF, TXF) adapted to provide a secondary communication channel (34) which locally interconnects the feeders (F1, F2, F3) of the stack to one another, and are each programmed to communicate their own identification code (ID1, ID2, ID3) to the following yarn feeder in the stack by means of the secondary communication channel (34).

Description

The present invention relates to an apparatus for feeding yarn from a plurality of stacks of yarn feeders to a textile machine.
As is known, a generic textile machine, such as a circular knitting machine, can be fed by a plurality of yarn feeder devices.
One type of feeder, known as positive, is provided with a motorized reel on which the yarn is wound (for example, 3 or 4 turns). By turning the reel, the feeder draws the yarn from an upstream spool and feeds it to the downstream textile machine. A local control unit can modulate the rotation rate of the reel on the basis of the signal received by a voltage sensor, so as to keep the tension of the yarn substantially constant at a desired value.
EP 2664569 discloses a yarn feeder of the positive type which is adapted to be mounted in a stacked configuration together with other identical feeders. The yarn feeders are mutually interconnected one above the other both mechanically, for example, by means of screws or snap connection systems, and electronically by means of male and female connectors arranged on respective opposite interconnection surfaces thereof.
From the electronic standpoint, the yarn feeders are all connected to a central control unit, which monitors and manages the coordinated operation of the various yarn feeders, typically by means of a linear BUS communication line (hereinafter "BUS").
Each yarn feeder connected on the BUS is provided with a unique identification code. This allows the central control unit to communicate only with an arbitrarily chosen feeder.
Conventionally, the assignment of the identification code requires some manual operations on the part of the operator. For example, after a numbering procedure has been launched, the operator presses a button on the yarn feeders in the order that corresponds to the desired numbering, which typically corresponds to the position of the yarn feeder in the stack.
This operation is not only susceptible of human error but also requires a lot of time, especially considering that a textile machine can be fed by tens of stacks of feeders, each stack possibly containing, for example, 3, 4 or more feeders.
In addition to this, it would be desirable to reduce the flow of data on the BUS during the weaving process, particularly in the error management steps (for example, yarn breakage, failure of a sensor, etc.).
Therefore, the aim of the present invention is to provide an apparatus that allows to automate the learning of the position of the feeders in the respective stacks on the part of the central control unit and to reduce the flow of data on the BUS during the weaving process, particularly in the error management steps.
This aim and other objects which will become better apparent from the continuation of the description are achieved by an apparatus having the characteristics described in claim 1, while the dependent claims describe other advantageous, albeit secondary, characteristics of the invention.
The invention is now described in greater detail with reference to some preferred but not exclusive embodiments thereof, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is a front view of a stack of yarn feeders that belongs to an apparatus according to a first embodiment of the invention;
Figure 2 is a block diagram of the stack of yarn feeders of Figure 1;
Figure 3 is a block diagram of a procedure for the learning of the position of the yarn feeders in the stack of Figure 1 on the part of a central control unit;
Figure 4 is a block diagram of an error management procedure in the stack of Figure 1;
Figure 5 is a front view of a stack of yarn feeders that belongs to an apparatus according to a second embodiment of the invention;
Figure 6 is a block diagram of the stack of yarn feeders of Figure 5;
Figure 7 is a block diagram of an error management procedure in the stack of Figure 5;
Figure 8 is a block diagram of a stack of yarn feeders that belongs to an apparatus according to a third embodiment of the invention;
Figure 9 is a block diagram of an error management procedure in a stack according to the embodiment of Figure 8;
Figure 10 is a block diagram of two stacks of yarn feeders belonging to an apparatus according to the embodiment of Figure 8;
Figure 11 is a block diagram of a procedure for the learning of the position of the yarn feeders in the stacks of Figure 10 on the part of a central control unit.
Figure 1 is a view of a stack 1 of positive yarn feeders 10 of the type to which the present invention relates.

Each one of the feeders 10 is provided with a motorized yarn winding reel 12. The yarn (not shown) is adapted to be wound between the reel 12 and a spacer pin 14 (for example, 3 or 4 turns). By turning the reel 12, the feeder 10 picks up the yarn from a spool located upstream (not shown) through a first input yarn guiding eyelet 15a and feeds it to the downstream textile machine (not shown) through an output yarn guiding eyelet 15b.
The feeder 10 can be provided with a local control unit (not shown) adapted to modulate the rotation rate of the reel 12 on the basis of the signal received from a tension sensor 16 arranged between the reel 12 and the output yarn guiding eyelet 15b, so as to stabilize the tension of the yarn fed to the textile machine on a desired value.
The feeders 10 are conventionally interconnected in a mutually stacked configuration both mechanically, for example, by means of screws (not shown), and electronically, by means of male connectors 20 and female connectors 22 respectively arranged on opposite interconnection surfaces thereof 26 and 24.
The feeder at the top of the stack 1 is connected to a terminal 28 provided with fixing means 30 for anchoring to a frame (not shown), typically an annular frame in the case of circular knitting machines.
In the block diagram of Figure 2, the three feeders of the stack 1 of Figure 1 are identified uniquely by respective references F1, F2, F3.
In a per se known manner, the feeders F1, F2, F3 are all connected electronically, by means of the connectors 20, 22, on a primary linear bus communication channel or BUS 32, by means of which they communicate bidirectionally with a central control unit CU.
The central control unit CU monitors and manages the coordinated operation of the various yarn feeders of the various stacks.
According to the invention, each one of the feeders F1, F2, F3 is provided with electronic interconnection means adapted to provide a secondary communication channel 34 which locally mutually interconnects the feeders F1, F2, F3 and is programmed to communicate an identification code of its own to the yarn feeder that follows it in the stack via the secondary communication channel 34.
In the present description, the term "follows" indicates an adjacent relationship between two feeders in a chosen direction that is valid for all the feeders of the stack (i.e., either from the feeder at the top of the stack to the feeder at the bottom, or vice versa).
On the practical level, with reference to Figure 1, the electronic interconnection means can be of the optical type and can comprise an LED (Light Emitting Diode) transmitter TXF that is located on one of the interfacing surfaces 24, and a receiving photodiode RXF which is aligned with it and is located on the other interfacing surface 26, which is adapted to abut against the first one with the feeders 10 in the stacked configuration.
In this embodiment, therefore, communication between the feeders 10 via the secondary communication channel 34 is unidirectional.
Figure 3 is a schematic view of a procedure for the learning of the position of the figures F1, F2, F3 in the stack on the part of the central control unit CU.
In Figure 3, the messages via the secondary communication channel 34 are designated by a double line, while the messages from the control unit CU and for the control unit CU, sent via the BUS 32, are designated respectively by a solid single line and by a dashed single line.
In a first step 101, each one of the yarn feeders F1, F2 and F3 communicates to the yarn feeder that follows it in the stack its own identification code ID1, ID2, ID3 by means of the secondary communication channel 34.
In a second step 102, the central control unit CU queries each one of the feeders F1, F2, F3 regarding the one that precedes it, via the BUS 32, with respective messages RQ1, RQ2, RQ3. Each one of the feeders F1, F2, F3, via the BUS 32, replies to the central control unit CU by communicating the identification code ID1, ID2 of the feeder that precedes it, except for the first feeder F1, at the top of the stack, which transmits a null signal NULL which indicates the fact that it is not preceded by any feeder.
At the end of the learning procedure, the central control unit CU has all the information required to determine the order in which the various feeders are arranged in the stack, for example, in order to control globally all the feeders of a stack in given steps of the weaving process.
Figure 4 is a schematic view of an error management procedure, by means of which the central control unit CU can stop automatically all the feeders F1, F2, F3 in the stack following an alarm signal received from one of them.
This procedure can be performed only after the control unit CU has learned the position of the various feeders within the respective stack, for example, by means of the learning procedure described previously and shown in Figure 3.
In a first step 201, a feeder, for example, the second feeder F2, communicates to the central control unit CU its own alarm status ALF2 via the BUS 32. In a per se known manner, the second yarn feeder F2 stops automatically when it enters the alarm status.
In a second step 202, the central control unit CU transmits to all the other feeders F1 and F3 of the stack a stop command STOP1, STOP3 via the BUS 32, so that it is easier for the operator to intervene on the second feeder F2. The feeders F1 and F3 reply with respective confirmation signals OK1 and OK3, again via the BUS 32.
In a third step 203, the second yarn feeder F2 communicates to the central control unit CU its own all-clear status ALF2 END via the BUS 32. In a per se known manner, the second yarn feeder F2 restarts automatically once the alarm status has ended. At this point the central control unit CU transmits to the other yarn feeders F1 and F3 of the stack a start command START 1, START3 via the BUS 32, and they reply with respective confirmation signals OK1 and OK3, again via the BUS 32.
Figures 5 and 6 show an alternative embodiment of the invention, which differs from the preceding one in that the secondary communication channel 34' is bidirectional, i.e., each one of the yarn feeders F1', F2', F3' is capable of transmitting/receiving information to/from any one of the two adjacent yarn feeders in the stack.
On the practical level, as shown in Figure 5, the bidirectional secondary communication channel 34' can be provided by installing on both interfacing surfaces 24', 26' both an LED (Light Emitting Diode) transmitter TXF' and a receiving photodiode RXF', obviously in reversed positions.
In this embodiment, the procedure for learning the position of the yarn feeders within the stack can be performed in a manner similar to the preceding embodiment.
Figure 7 shows an error management procedure that utilizes the bidirectional secondary communication channel 34' to disable directly all the yarn feeders of the same stack when one of them enters an alarm status, without requiring the intervention of the central control unit CU' via the bus 32'.
Therefore, this error management procedure can be performed even if the position learning procedure has not been performed.
In particular, in a first step 301 a yarn feeder, for example, the third feeder F3', communicates to the central control unit CU' the alarm state ALF3', via the BUS 32'. In a per se known manner, the third feeder F3' stops automatically when it is in the alarm status. The central control unit CU' stops the machine.
In a second step 302, by means of the secondary communication channel 34', the third feeder F3' communicates the alarm status ALF3' to the adjacent feeder, in this case the second feeder F2', which stops and communicates the alarm status ALF2' to the adjacent feeder, in this case the first feeder F1', which in turn stops.
In a third step 303, the third feeder F3' communicates to the central control unit CU' the all-clear status ALF3_END', via the BUS 32'. In a per se known manner, the third feeder F3 restarts automatically when the alarm status ceases. The central control unit CU' restarts the machine. At this point, via the secondary communication channel 34', the third feeder F3' communicates the all-clear status ALF3_END' to the adjacent feeder, in this case the second feeder F2', which restarts and communicates the all-clear status ALF2_END' to the adjacent yarn feeder, in this case the first feeder F1', which in turn restarts.
Figure 8 shows a further embodiment of the invention, which differs from the preceding ones in that the terminal M" to which the feeder at the top of the stack is connected is provided with its own control unit for the management of one or more sensors, for example, yarn breakage sensors (not shown) which are independent of the feeders, and is also configured to communicate bidirectionally via the secondary communication channel 34". In the previously described example, the terminal M" can be provided with its own LED transmitter (not shown) in order to transmit data to the first yarn feeder F1" of the stack, and with its own receiver photodiode (not shown) in order to receive data from it in case of a bidirectional connection.
Figure 9 relates to the embodiment of Figure 8 and shows an error management procedure that utilizes the secondary communication channel 34" to communicate the alarm status and the all-clear status from the terminal M" to the yarn feeders F1", F2", F3" of the stack. This procedure can also be performed in the case of a unidirectional secondary communication channel.
In a first step 401, the terminal M" communicates the alarm status of the sensor ALS" to the first yarn feeder F1" of the stack, which is adjacent thereto, by means of the secondary communication channel 34".
In a second step 402, the first yarn feeder F1" enters the alarm status, stops, and communicates, via the BUS 32", the alarm status ALF1" to the central control unit CU". The central control unit CU" stops the textile machine.
In a third step 403, the first yarn feeder F1" communicates the alarm status ALF1" to the second yarn feeder F2" that follows it in the stack. The second yarn feeder F2" stops and communicates the alarm status ALF2" both to the third yarn feeder F3" that follows it in the stack, via the secondary communication channel 34", and advantageously to the central control unit CU", via the BUS 32". The third yarn feeder F3" stops and communicates advantageously the alarm status ALF3" to the central control unit CU" via the bus 32".
In a fourth step 404, the terminal M" communicates the all-clear status of the sensor ALS_END" to the first yarn feeder F1" of the stack via the secondary communication channel 34". The first yarn feeder F1" restarts and communicates the all-clear status ALF1_END" both to the central control unit CU", via the BUS 32", and to the second yarn feeder F2" via the secondary communication channel 34". The second yarn feeder F2" restarts and communicates the all-clear status ALF2_END" both to the third yarn feeder F3" via the secondary communication channel 34" and advantageously to the central control unit CU", via the BUS 32". The third yarn feeder F3" restarts and advantageously communicates the all-clear status ALF3_END" to the central control unit CU" via the BUS 32".
One advantage of this solution is that in case of an alarm related to a sensor, the error indication is inherently close to the point where the error occurred, in this case before the feeder. In the known solutions in which, for example, the sensors are all connected to a separate bus or communicate on the main bus, there is no direct association between the sensor and the feeder. This circumstance, as is well known to the person skilled in the art, complicates alarm management in known solutions.
Figure 10 shows two stacks of yarn feeders Sa", Sb", each of which has at the top a respective terminal Ma", Mb" equipped to communicate via the secondary communication channel 34a", 34b". Each one of the stacks Sa", Sb" is composed of two yarn feeders F1a", F2a" and F1b", F2b" respectively. Each one of the feeders is connected on the BUS 32".
Figure 11 shows a procedure for the learning of the position of the yarn feeders F1a", F2a" and F1b", F2b" which are distributed on the two stacks Sa", Sb" on the part of the central control unit CU".
This procedure can be performed, in this embodiment of the invention, by storing in each one of the terminals Ma", Mb" across the respective stacks Sa", Sb" a respective terminal identification code IDMa", IDMb".
In a first step 501, the terminals Ma", Mb" communicate their identification codes IDMa" and IDMb" to the first yarn feeders F1a" and F1b" of the respective stacks Sa" and Sb" via the respective secondary communication channels 34a" and 34b". Then the first yarn feeders F1a" and F1b" communicate their own identification codes IDF1a" and IDF1b" to the second yarn feeders F2a" and F2b", via the respective secondary communication channels 34a" and 34b".
In a second step 502, the central control unit CU" queries all the yarn feeders as to which one precedes them, so as to learn their placement within the respective stacks, in a manner similar to what has been described in relation to the first embodiment and shown in Figure 3.
In a third step, preferably, the central control unit CU" renumbers all the yarn feeders according to their positions in the respective stacks, or according to the pattern most suitable for the specific application, for example, IDF1,1" and IDF1,2" as regards the feeders in the first stack Sa" and IDF2,1" and IDF2,2" as regards the feeders in the second stack Sb".
Of course, although only two stacks, each containing two feeders, have been referenced for the sake of simplicity, this procedure is applicable to an indefinite number of stacks containing an indefinite number of feeders, within the limits set by the technology being used.
In practice it has been found that the apparatus according to the invention fully achieves the intended aim and objects, since it allows to automate the learning of the position of the feeders in the respective stacks on the part of the central control unit, so as to prevent the risks of human error and speed up the startup steps of the apparatus.
Data transmission via the secondary communication channel, according to the intended aim and objects, furthermore allows to reduce the flow of data on the BUS during the weaving process, particularly in the error management steps.
Some preferred embodiments of the invention have been described, but of course the person skilled in the art may provide different modifications and variations within the scope of the appended claims.
In particular, as already mentioned earlier, the number of stacks and the number of feeders in each stack can vary broadly according to the application.
Furthermore, the secondary communication channel may use electronic interconnection means that are different from the optical ones used in the examples described herein, including physical electronic connectors which, for example, can also be arranged on the two opposite interfacing surfaces of the feeder so as to engage directly when the stack is formed.
Additionally, the error management procedures described herein by way of example have the purpose of illustrating some possible practical applications of the apparatus according to the invention. However, it is understood that the secondary communication channel may be used to propagate within the stack any kind of message, therefore not only identification messages or alarm messages but also, for example, messages related to the setting of a feeder (for example so that all the feeders of the stack can be set in the same manner), status messages, etc.
The disclosures in Italian Patent Application No. 102019000016340 from which this application claims priority are incorporated herein by reference.
Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

An apparatus for feeding yarn to a textile machine, comprising at least one stack of feeders (F1, F2, F3), each of which is provided with a motorized yarn winding reel (12) adapted to draw the yarn from a spool in order to feed it to a textile machine, said feeders (F1, F2, F3) being all connected electronically on a primary communication channel (32) in order to communicate bidirectionally with a central control unit (CU), characterized in that each one of said feeders (F1, F2, F3) is provided with electronic interconnection means (RXF, TXF) adapted to provide a secondary communication channel (34) which locally interconnects the feeders (F1, F2, F3) of the stack to one another, and is programmed to communicate its own identification code (ID1, ID2, ID3) to the yarn feeder that follows it in the stack by means of said secondary communication channel (34).
The apparatus according to claim 1, characterized in that said secondary communication line (34) is unidirectional.
The apparatus according to claim 1, characterized in that said secondary communication line (34) is bidirectional.
The apparatus according to one or more of claims 1-3, characterized in that electronic interconnection means are arranged on two opposite interfacing surfaces (24, 26) of said yarn feeder (10), which are adapted to mutually abut with the yarn feeders in a stacked configuration.
The apparatus according to claim 4, characterized in that electronic interconnection means comprise an LED (TXF) arranged on a first one of said interfacing surfaces (24), and a receiving photodiode (RXF) arranged on a second one of said interfacing surfaces (26).
A procedure for learning the position of the yarn feeders within a stack belonging to an apparatus according to one ore more of claims 1-5, characterized in that it comprises the following steps:
- each one of said feeders (F1, F2 and F3) communicates to the yarn feeder that follows it in the stack its own identification code (ID1, ID2, ID3), via said secondary communication channel (34),

- said central control unit (CU) queries each one of said feeders (F1, F2, F3) as to which one follows it in the stack via said primary communication channel (32),

- each one of said feeders (F1, F2, F3), via said primary communication channel (32), replies to said central control unit (CU) by communicating the identification code of the feeder that follows it, except for the first feeder (F1) at the top of the stack, which transmits a signal indicating the fact that it is not followed by any feeder (NULL).
An error management procedure for an apparatus according to one of claims 1-5, characterized in that it comprises the following steps:
- performing a procedure by which the central control unit (CU) learns the position of the feeders within the respective stack,

- when a feeder (F2) communicates to the central control unit (CU) its own alarm status (ALF2) via said primary communication channel (32), said central control unit (CU) transmits a stop command (STOP1, STOP3), via said primary communication channel (32), to all the other feeders (F1, F3) of the stack, which reply with respective confirmation signals (OKI, OK3) via said primary communication channel (32),

- when a feeder (F2) communicates to the central control unit (CU) its own all-clear status (ALF_END2), via said primary communication channel (32), said central control unit (CU) transmits a start command (START1, START2), via said primary communication channel (32), to all the other feeders (F1, F3) of the stack, which reply with respective confirmation signals (OKI, OK3) via said primary communication channel (32).
The error management procedure for an apparatus according to claim 3, characterized in that it comprises the following steps:
- an alarmed yarn feeder (F3') communicates an alarm message (ALF3') to the central control unit (CU') via said primary communication channel (32'),

- the alarm status propagates among all the yarn feeders of the stack by means of respective alarm messages (ALF2', ALF3') transmitted via said secondary communication channel (34'),

- said alarmed yarn feeder (F3') communicates to the central control unit (CU') an all-clear message (ALF3_END') via said primary communication channel (32'),

- the all-clear status (AL_END') propagates among all the yarn feeders of the stack via respective alarm messages (ALF2_END', ALF3_END') transmitted via said secondary communication channel (34').
The error management procedure for an apparatus according to one ore more of claims 1-5, wherein the feeder at the top of the stack is connected to a terminal (M") which is connected to receive signals from at least one sensor and is connected to said secondary communication channel (34), characterized in that it comprises the following steps:
- said terminal (M") sends a sensor alarm message (ALS") to the first yarn feeder of the stack (F1") via said secondary communication channel (34"),

- said first yarn feeder of the stack (F1") sends, via said primary communication channel (32"), an alarm message (ALF1") to said central control unit (CU"),

- the alarm status propagates among all the other feeders of the stack via respective alarm messages (ALF1", ALF2") via said secondary communication channel (34'),

- said terminal (M") sends a sensor alarm end message (ALS_END") to the first yarn feeder (F1") via said secondary communication channel (34"),

- said first yarn feeder (F1") communicates, via said primary communication channel (32'), the all-clear status (ALS_END") to said central control unit (CU"),

- the all-clear status propagates among all the other feeders of the stack by means of respective all-clear messages (ALF1_END", ALF2_END") sent via said secondary communication channel (34").
The procedure according to claim 9, characterized in that each one of the feeders of the stack sends a respective alarm message (ALF2", ALF3") and an all-clear message (ALF2_END", ALF3_END") also to said central control unit (CU").
A_ procedure for learning the position of yarn feeders distributed on a plurality of stacks belonging to an apparatus according to one ore more of claims 1-5, wherein the feeder at the top of each one of said stacks is connected to a respective terminal (Ma", Mb") which is adapted to receive signals from at least one sensor and is connected to the secondary communication channel (34a", 34b") of the respective stack, characterized in that it comprises the following steps:
- a respective identification code of the terminal (IDMa", IDMb") is stored in each one of the terminals (Ma", Mb"),

- each one of said terminals (Ma", Mb") communicates its own identification code (IDMa" and IDMb") to the first yarn feeders (F1a", F1b") of the respective stacks (Sa", Sb"), via the respective secondary communication channels (34a", 34b"),

- each one of said feeders (F1a", F1b") communicates to the yarn feeder that follows it in the stack its own identification code, via the respective secondary communication channels (34a" and 34b"),

- said central control unit (CU') queries all the yarn feeders as to which one precedes them so as to learn their placement within the respective stacks.
The procedure according to claim 11, characterized in that, in a last step, said central control unit (CU') renumbers all the yarn feeders on the basis of the positions in the respective stacks.