THEREOF

The subject of the present invention is a sensor for controlling yarn feed tc a textile machine according to the preamble of the main claim. A further subjeci of the invention is a method for choosing a particular and selected operating mode of said sensor.

Various types of sensor are known suitable for detecting at least one specific characteristic of a thread or yarn fed to a textile machine: for example, sensors are known suitable for detecting the running or state of rest of the yarn and/or for detecting the speed and/or tension of said yarn during its movement towards the textile machine. Said sensors are provided with a casing positioned on a supporting structure of the machine or in the vicinity of the latter; the casing is furthermore provided with known means (mechanical, optical and/or electronic) suitable for detecting the above-mentioned characteristic of the yarn. Display means and buttons are also provided in the casing suitable for enabling a user to set or re-set data relative to the tension and/or speed of the yarn to be controlled in addition to other operating parameters of the device considered acceptable for correct feed of the yarn to a textile machine.

A known solution of this type is contained in EP619261 which describes a method and a device for adjusting and maintaining a predefined tension of a yarn fed to a textile machine.

Said patent text does not describe, however, the possibility of the operator setting a plurality of operating modes of the yarn control device, intervening on the internal operating parameters of the device itself according to specific varying operating conditions (such as the type of yarn or its section).

Usually a textile machine comprises many sensors of the type cited, all connected to a device for controlling correct feed of the yarn to the machine. The data detected by each sensor are transferred, via known methods, to means of said device for control of the data detected which, according to the latter, intervene on the sensor operating modes (for example by causing the sensor to modify the yarn running tension) or on the textile machine (for example by stopping operation thereof if the sensor detects an incorrect state of movement of the yarn, or an absence of the latter).

Said known solutions therefore concern sensors of a characteristic of the yarn which are substantially detectors of said characteristic and can operate effectively only if connected to a yarn feed control device, which may or may not be part of the usual operating control device of the textile machine. A user of the latter who wishes to obtain a product of acceptable quality must therefore adopt a device of the type cited (which substantially comprises one or more sensors connected to a yarn feed control unit separate from the sensor) or must possess a textile machine with "electronics" (i.e. the set of all the electrical/electronic components that permit correct operation) already provided with interface for the above-mentioned sensors.

US6476619 describes a method and a device for accurately measuring and calculating at high speed the humidity and density contents of fibrous material, homogeneous or non-homogeneous, via the use of a microwave resonator device and calculation algorithms. With this device, automatic feedback is obtained on the density quality of the fibrous material, via measurement, control and regulation of the humidity content, temperature and feed speed. Said quality control feedback and regulation are automatically actuated via a connection between a central processing unit provided in the device and a machine separating and processing the CARD fibres (CARD fiber separating machine).

The algorithms described are calculation algorithms (and not algorithms for control of the yarn process) suitable for permitting processing of the data received by the central unit. Said patent does not comprise the possibility of a user or an operator selecting a plurality of intervention modes (according to predefined control algorithms) on the fibrous material.

From the above it appears evident that the solutions in the state of the art are costly (if, in addition to the sensors, the user also has to acquire the above- mentioned control device or even an entire textile machine with said device fitted inside) and also penalise the user if he cannot modify the electronics of the textile machine he is already operating in order to equip it with the above- mentioned control device.

The object of the present invention is to provide a sensor for controlling the feed of a thread or a yarn to a textile machine which can be selectively used according to different operating modes or according to different control algorithms, without the need to connect the same sensor to a separate operating control and command unit. A further object is to provide a sensor of the type cited which permits control of the feed of the thread or yarn to a textile machine even if the control electronics of the latter are not provided with a device for controlling the feed of the thread or yarn to the machine, it being possible to use said sensor completely independently and without the need for connection to a different and separate independent yarn feed control device.

In other words, the object of the invention is to provide a sensor suitable for controlling yarn feed with at least one of its characteristics or parameters

(tension or speed) maintained constant which allows for modification of the control algorithm of said feed according to different needs such as type or section of the yarn.

A further object is to provide a sensor of the type cited which can be produced according to the procedures and conformations of the sensors currently produced, thus avoiding a significant increase in the production costs of the sensor. A further object is to provide a sensor of the type cited which is simple to use.

A further object of the invention is to provide a method for simply and rapidly programming a thread or yarn feed control sensor of the type cited above according to predefined and different operating parameters such as to permit a plurality of different yarn control modes.

These and further objects which will be evident to a person skilled in the art are obtained by a sensor and a method as claimed in the attached claims.

For a better understanding of the present invention, the following drawings are attached, purely by way of non-limiting example, in which: figure 1 shows a generic diagram of a sensor for controlling yarn feed to a textile machine obtained according to the present invention; figure 2 shows a flow diagram illustrating a method according to the invention; and figure 3 shows in a perspective view an example of embodiment and use of a sensor according to the invention.

With reference to the figures cited, a sensor suitable for controlling the correct feed of a yarn F to a textile machine T is indicated generically by 1 and comprises a casing 2 suitable for being combined with an adequate support (not shown) positioned in the vicinity of the textile machine; said support may or may not be part of the latter. The sensor 1 has usual detection means 4 cooperating with the yarn F after, for example, it has been unwound from a corresponding spool 5 and during its movement or running towards the machine T. Said detection means can be of the mechanical type, such as one or more movable arms overhanging the casing 2 or a rotating element positioned on one face of the latter; optical as shown in figure 3 where the sensor 1 (of known type and sold by the applicant under the name IS3) comprises a casing 2 with opposite arms 7 provided at the ends with optical elements 8 and 9 suitable for detecting at least the presence of the yarn between them; electrical, electronic or defined by components that exploit mechanical and electrical characteristics (such as piezoelectric detectors). The above-mentioned detection means, being of known type and easily accessible in the state of the art, will not be further described.

According to the invention, said sensor 1 comprises a means for control of said detection and means suitable for modifying the modes of, said control according to a plurality of control algorithms pre-set and stored in the sensor; the sensor 1 also comprises selector means suitable for allowing the selection of one of said algorithms so that the sensor can permit a plurality of different yarn control modes according to different needs such as, for example, different yarn section, different yarn materials and yarns with different elasticity and elongation characteristics.

Thanks to the invention, using the same sensor 1 , an operator can select different algorithms or control methods, also operating with yarns having different characteristics. More specifically, inside the casing 2 of the sensor 1 there is a control unit

10, preferably and advantageously microprocessor-operated, defining the control means of the characteristic identified by the detection means in addition to the means suitable for modifying said control mode. The unit 10 is connected to the detection means and to a memory unit 11 containing the different control algorithms (based on predefined operating parameters differing from algorithm to algorithm) according to which different possible yarn feed controls are performed. The unit 10 dialogues with said memory unit (or simply "memory") 11 according to the intervention of a user on the selector means defined by a selector 13 which can be specifically provided on the casing 2 for the selection of one of various operating algorithms or which can be a functional component of the sensor 1 used so as to select the above-mentioned algorithm obtained mechanically (for example via a movable button), electrically (for example via a touch button) or optically (for example via the interruption of an "optical contact" between the optical elements 8 and 9 of the sensor of figure 2). Said intervention is defined by the method according to the invention which will be described in relation to figures 2 and 3.

It is firstly assumed that the memory 11 contains four different operating algorithms of the sensor 1 (for example a sensor suitable for detecting the yarn feed status), said algorithms being chosen, for example, in order to allow the sensor to operate effectively with yarns of different section or different material or different elasticity and elongation, or with the same yarn but in different operating conditions (according to variations in the yarn pick-up speed or draw). In order to select the desired operating algorithm (for example chosen according to the yarn being worked), the user intervenes on the selector 13: for example, in the case of the sensor of figure 2, the user places his finger D between the optical elements 8 and 9 thus allowing the unit 10 to detect the presence thereof. This action corresponds to pressing a button or a touch key. It should be noted that by maintaining the action on the selector 13 for a brief period (for example 1 or 2 seconds and in any case less than a pre-established value t, for example 3 seconds), the unit 10 switches the status of the sensor 1 ; said switching is visually identified by the activation of an illuminated display device 17 (for example a LED) and/or an acoustic element, connected to the unit 10. In this way, the status of the sensor passes for example from on (LED activated) to off (LED de-activated) or vice versa. If the sensor 1 is already on, a series of warnings is generated before switching off, for example blinkings of the LED, equal to the number of the operating algorithm currently followed by the sensor 1 during its operation.

The method according to the invention begins (block 30 of figure 3) with evaluation of the status of the yarn F, i.e. whether the yarn is running or not. If the yarn is already moving, "programming" of the sensor 1 (i.e. the selection of a particular and predefined operating algorithm present in the memory 11) is stopped (block 31). If, on the other hand, the yarn is at a standstill, the program goes to block 32 where a check is performed to verify whether the sensor 1 is activated (on) or de-activated (off). According to said check, one of two different sequences can be followed, shown in figure 3.

If the sensor 1 is on, a check is performed to verify action on the selector 13 (block 33): if it is not detected, the programming is stopped (block 34). If, on the other hand, an action is performed on the selector 13, a check is carried out to verify (block 35) whether said action occurs for a period longer than the pre-established value t cited above. If so, the program goes on to block 36 where the first of the four algorithms stored is selected (and the display device 17 is activated one single time - corresponding to the algorithm number 1); if the check is negative, the program certifies that the action on the selector 13 represents the desire to de-activate the sensor 1 and goes on to block 37 (sensor switch-off) and then to block 38 where the series of light (and/or acoustic) signals is generated corresponding in number to the number of the algorithm currently followed by the sensor for control of the yarn. The program then goes on to block 39 where it terminates.

If on the other hand the program went to block 36, a check is subsequently performed (block 40) to verify whether the action on the selector 13 is continuing: if not, the program goes on to block 41 where the selected operating algorithm is stored. If the answer is positive, the program goes on to block 42 corresponding to the selection of program number 2 with consequent dual activation of the display device 17.

The program then checks (block 43) whether the action on the selector 13 persists: if not, it goes on to block 41; if so, it certifies selection of the third operating algorithm (block 44) with consequent triple activation of the display device 17.

The program then checks again (block 45) whether the action on the selector 13 persists: if not, it goes on to block 41 ; if so, it certifies selection of the fourth operating algorithm (block 46) with quadruple activation (in time sequence) of the display device 17. The program then checks (block 47) whether the action on the selector 13 persists: if the check is negative, it goes on to block 41 (storage of the selected operating algorithm); if positive, it exits from the "programming" or selection of the algorithm (block 48). An analogous procedure is followed if the check performed in block 32 indicates that the sensor is off. This involves transition to block 50 corresponding to block 33 cited above. If there is no action on the selector 13, the program returns to block 31 , otherwise it goes to block 51 corresponding to block 35. If the action on the selector lasts beyond the pre-set time t (cited above), the program goes on to block 52 corresponding to block 36, otherwise it goes to block 53, in which the sensor 1 is activated, and from there to block 39.

If the program is in the phase or step of the method corresponding to block

52, it follows the procedure indicated by the blocks 54, 55, 56, 57, 58, 59, 60 corresponding to the procedure comprising the blocks described above 40, 42, 43, 44, 45, 46 and 47 which should be referred to for the sake of brevity.

The above description highlights that, both with the sensor activated and de-activated, the action on the selector 13 for a period longer than a predefined time t (for example equal to 3 seconds) triggers in sequence the various implementation phases of the operating algorithm selection method. Each phase (i.e. the corresponding algorithm) is highlighted by activation of the display device 17 for a period corresponding to the algorithm selected (in the example, one, two, three or four times). It is sufficient to terminate the action on the selector 13 to select the operating algorithm of the sensor 1 chosen at that particular moment (block 41). It should be noted that even with the sensor de-activated, after selection of its operating mode ("programming"), it is automatically activated after the yarn F has started to run, cooperating with the yarn for a predefined period, for example equal to the period or time t cited above. Signalling of activation of the sensor is indicated by activation of the display device 17. The invention therefore allows the use of one single yarn feed control sensor which is able to operate according to different operating algorithms, preset and stored in an internal memory unit and selected according to different needs, for example yarn type or section; there is no need for any further sensor control devices, which are certainly more costly and not always easy to position on or near the textile machine if they are independent of it, or for the machine control electronics to be pre-set for said sensor control. This allows the yam to be controlled according to different operating modes without having to intervene on the machine or without having to equip the latter with sensors and correlated control devices which can also be fairly costly; said yarn control is obtained alternatively with one single sensor which incorporates the functions of a component suitable for controlling parameters of the yarn fed and the possibility of varying, in a predefined manner, the control modes of said parameters. This involves a simplification of both the machine and the yarn control "system", i.e. the set of all the components and devices necessary for correct feed of the thread or yarn to the above-mentioned machine.

It should be noted that the sensor can also be pre-set to intervene directly on the machine T to block the operation thereof if the sensor detects an anomaly in the characteristic of the thread or yarn controlled during feeding to said machine. This is indicated in figure 1.

A particular embodiment of the invention has been described. Others are possible in the light of the preceding description and comprise, for example, sensors operating on different characteristics of the yarn or sensors which can operate according to algorithms (in a number higher than four); said embodiments must be considered as falling within the scope of the following claims.