DEVICE FOR FEEDING YARN OR YARNS FOR KNITTING MACHINES FOR HOSIERY OR THE LIKE

Abstract

A device for feeding yarn or yarns for knitting machines for hosiery or the like, comprising a supporting structure which supports at least one yarn finger having an elongated shape and being pivoted, at an intermediate portion thereof, to the supporting structure about a corresponding rotation axis and having, proximate to a longitudinal end thereof, a passage for the yarn or yarns to be fed to the needles of the knitting forming machine, the device for feeding yarn or yarns comprising an electromagnetically actuated device which comprises at least one magnet which is fixed to the at least one yarn finger and at least one electric coil which is laterally adjacent to the at least one yarn finger and is connected to the supporting structure.

Claims

1-17. (canceled)

18. A device for feeding yarn or yarns for knitting machines for hosiery or the like, comprising a supporting structure which supports at least one yarn finger which has an elongated shape and is pivoted, at an intermediate portion thereof, to said supporting structure about a corresponding rotation axis and having, proximate to a longitudinal end thereof, a passage for the yarn or yarns to be fed to the needles of the knitting forming machine, an electromagnetically actuated device being provided which acts on command on said at least one yarn finger for its rotation, with respect to said supporting structure, about the corresponding rotation axis, from an inactive position to at least one active position, which is angularly spaced with respect to said inactive position about said rotation axis, or vice versa, wherein said electromagnetically actuated device comprises at least one magnet which is fixed to said at least one yarn finger and at least one electric coil which is laterally adjacent to said at least one yarn finger and is connected to said supporting structure, said at least one electric coil being able to be supplied electrically to generate a magnetic field that interacts with said at least one magnet to actuate the rotation of said at least one yarn finger about the corresponding rotation axis with respect to said supporting structure.

19. The device according to claim 18, wherein said yarn fingers are pivoted to said supporting structure about a same rotation axis.

20. The device according to claim 18, wherein said at least one magnet is fixed to a portion of the corresponding yarn finger that is located on an opposite side with respect to said passage for the yarn or yarns with respect to said rotation axis.

21. The device according to claim 20, wherein for each one of said yarn fingers there is a corresponding pair of electric coils which is composed of two electric coils which face two opposite faces of the portion of the corresponding yarn finger that supports said at least one magnet.

22. The device according to claim 21, wherein said portion of the yarn finger that supports said at least one magnet is substantially plate-like and is crossed by a seat that accommodates a corresponding magnet; said two electric coils being arranged so that their axis is perpendicular to the opposite faces of said portion of the corresponding yarn finger that supports said magnet.

23. The device according to claim 21, wherein said two electric coils are coaxial.

24. The device according to claim 21, wherein said at least one yarn finger comprises at least two laterally mutually adjacent yarn fingers.

25. The device according to claim 21, further comprising magnetic field shielding elements interposed between the two electric coils that act on the magnets of two contiguous yarn fingers.

26. The device according to claim 25, wherein said magnetic shielding elements are constituted by plates made of ferromagnetic material, which are arranged at right angles to said rotation axis and are connected to said supporting structure.

27. The device according to claim 26, wherein the electric coils that act on the magnets of two contiguous yarn fingers are connected to two opposite faces of a same plate that constitutes one of said shielding elements.

28. The device according to claim 25, wherein each one of said electric coils is constituted by at least one electrically conducting wire which is spirally wound and is applied to a face of said plate that constitutes one of said shielding elements.

29. The device according to claim 18, wherein at least one of said yarn fingers can rotate on command about the corresponding rotation axis with respect to said supporting structure from said inactive position to at least one first active position and to at least one second active position which is arranged between said inactive position and said first active position or vice versa.

30. The device according to claim 18, further comprising means for detecting the rotational position of at least one of said yarn fingers about the corresponding rotation axis with respect to said supporting structure.

31. The device according to claim 30, wherein said detection means comprise a Hall-effect detector interposed between said at least one of said yarn fingers and said supporting structure.

32. The device according to claim 31, wherein said Hall-effect detector comprises a magnetic element applied to said at least one yarn finger and a corresponding linear magnetic Hall-effect sensor arranged on said supporting structure.

33. The device according to claim 21, further comprising an electronic control board which supplies electric power to said electric coils according to a processing program that is preset in an electronic control element.

34. The device according to claim 33, wherein the rotational position of said at least one yarn finger is actuated and controlled by means of a closed-loop feedback control system by said electronic control board, which is connected to said means for detecting the rotational position of said at least one yarn finger and controls the power supply of the pair of electric coils between which said at least one yarn finger is arranged as a function of a rotational value detected by said detection means.

Description

[0020] Further characteristics and advantages of the invention will become better apparent from the description of a preferred but not exclusive embodiment of the device for feeding yarn or yarns according to the invention, illustrated by way of nonlimiting example in the accompanying drawings, wherein:

[0021] FIG. 1 is a perspective view of a device for feeding yarn or yarns according to the invention, showing only three yarn fingers, shown in three different operating positions;

[0022] FIG. 2 is a view of the device of FIG. 1, with a part removed in order to better illustrate the components of the yarn finger assembly;

[0023] FIG. 3 is a lateral elevation view of the device according to the preceding figures;

[0024] FIG. 4 is a top plan view of the device of FIGS. 1 to 3;

[0025] FIG. 5 is a lateral elevation view of a yarn finger;

[0026] FIG. 6 is a top plan view of the yarn finger of FIG. 5;

[0027] FIG. 7 is a lateral elevation view of a component of the device according to the invention;

[0028] FIG. 8 is a top plan view of the component of FIG. 7;

[0029] FIGS. 9 to 11 are lateral elevation views, with some components removed, of the device according to the invention, highlighting the different operating positions of a yarn finger;

[0030] FIG. 12 is a control and monitoring diagram of the rotational position of a yarn finger about the corresponding rotation axis.

[0031] With reference to the cited figures, the device for feeding yarn or yarns according to the invention, designated generally by the reference numeral 1, comprises a supporting structure 2, shown schematically and in dashed lines only in FIG. 3, which is designed to be fixed to the supporting structure of a knitting machine for hosiery or the like, at a feed or drop of the machine. The supporting structure 2 supports at least one yarn finger 3, which has an elongated shape and is pivoted, at an intermediate portion thereof, to the supporting structure 2 about a corresponding rotation axis 4.

[0032] In the illustrated embodiment, the device for feeding yarn or yarns according to the invention is composed of three yarn fingers 3 arranged side by side, but the number of yarn fingers 3 may vary according to the requirements. In particular, the device for feeding yarn or yarns according to the invention can comprise even just a single yarn finger 3.

[0033] Each yarn finger 3 has, proximate to one of its longitudinal ends, a passage 5 for the yarn or yarns to be fed to the needles of the knitting forming machine. As in yarn fingers of the known type, this passage 5 for the yarn can be defined within a tube 6 which is fixed to the longitudinal end of the yarn finger 3 designed to be directed toward the needle holder, which is constituted by the needle cylinder in circular knitting machines for hosiery or the like.

[0034] The device for feeding yarn or yarns according to the invention comprises an electromagnetically actuated device 7 which acts on command on each yarn finger 3 in order to cause its rotation with respect to the supporting structure 2 about the corresponding rotation axis 4, so as to obtain the transition of the corresponding yarn finger 3 from an inactive position, in which the longitudinal end of the yarn finger 3 provided with the tube 6 is in a position that is spaced from the work region of the needles of the machine in order to prevent the pickup of the yarn, dispensed through the tube 6, on the part of the needles that are moved to knit at the feed or drop being considered, to at least one active position, which is angularly spaced from the inactive position about the rotation axis 4, in which the longitudinal end of the yarn finger 3 provided with the tube 6 is in a position that is closer to the needle work region of the machine in order to allow the pickup of the yarn, dispensed through the tube 6, on the part of the needles that are moved to knit at the feed or drop being considered.

[0035] According to the invention, the electromagnetically actuated device 7 comprises at least one magnet 8 which is fixed to each yarn finger 3 and at least one electric coil 9a, 9b, which is laterally adjacent to each yarn finger 3 and is connected to the supporting structure 2. As shown in the figures, the electric coil or coils 9a, 9b are laterally adjacent to each yarn finger 3 along a direction that is parallel to the rotation axis 4. The at least one electric coil 9a, 9b can be supplied with electric power in order to generate a magnetic field, which interacts with the magnet 8, so as to cause the rotation of the corresponding yarn finger 3 about the corresponding rotation axis 4 with respect to the supporting structure 2 in order to produce its transition from the inactive position to the at least one active position or vice versa.

[0036] Preferably, the yarn fingers 3 are pivoted to the supporting structure 2 about a same rotation axis 4, being mounted on the same shaft which defines, with its axis, said rotation axis 4.

[0037] Without altering the fact that multiple magnets can be arranged on the same yarn finger 3, depending on the actuation requirements of said yarn finger 3, in the illustrated embodiment there is a single magnet 8 for each yarn finger 3. Said magnet 8 is fixed to the portion 10 of the corresponding yarn finger 3 that is arranged on the opposite side with respect to the passage 5 for the yarn or yarns, i.e., opposite with respect to the tube 6, relative to the rotation axis 4 of the yarn finger 3.

[0038] Conveniently, the portion 10 of the yarn finger 3 that supports the magnet 8 is substantially plate-like and is crossed by a seat 11 which accommodates the corresponding magnet 8. Said portion 10 of the yarn finger 3 is preferably made of molded synthetic material.

[0039] Preferably, for each yarn finger 3 a corresponding pair of electric coils 9a, 9b is provided, wherein each pair of coils is composed of two electric coils 9a, 9b which face the two opposite faces of the portion 10 of the corresponding yarn finger 3 that supports the magnet 8.

[0040] The two electric coils 9a, 9b of each pair of electric coils are arranged with their axis at right angles to the opposite faces of the portion 10, which is plate-shaped, of the corresponding yarn finger 3 that supports the magnet 8.

[0041] In the illustrated embodiment, the two electric coils 9a, 9b of each pair of coils are coaxial. In particular, the various electric coils 9a, 9b of the device for feeding yarn or yarns according to the invention are all coaxial.

[0042] Conveniently, if the device for feeding yarn or yarns comprises at least two yarn fingers 3 arranged side by side, elements for shielding the magnetic field are provided and are interposed between the two electric coils 9a, 9b, which belong to two pairs of mutually different electric coils, which act on the magnets 8 of two contiguous yarn fingers 3 so that the actuation of one yarn finger 3, actuated by means of the electric power supply of a pair of electric coils 9a, 9b, does not interfere with or does not disturb the actuation of a contiguous yarn finger 3.

[0043] The shielding elements are preferably constituted by plates 12 made of ferromagnetic material which are arranged at right angles to the rotation axis 4 of the yarn fingers 3 and are connected to the supporting structure 2.

[0044] Advantageously, the electric coils 9a, 9b that act on the magnets of two contiguous yarn fingers 3 are connected to the two opposite faces of a same plate 12 that constitutes one of the shielding elements.

[0045] In this manner, the advantage is achieved of simplifying the assembly of the device for feeding yarn or yarns according to the invention and of keeping its overall dimensions small in a direction that is parallel to the rotation axis 4, thus making easier its placement on the machine both during design and during assembly.

[0046] Conveniently, each one of the electric coils 9a, 9b is constituted by one or more wires made of electrically conducting material wound spirally around the axis of the electric coil 9a, 9b and applied to one face of the plate 12 that constitutes one of the shielding elements. This configuration and arrangement of the electric coils 9a, 9b also allows to contain the dimensions of the device for feeding yarn or yarns according to the invention in a direction that is parallel to the rotation axis 4.

[0047] Preferably, at least one of the yarn fingers 3 can rotate on command about the corresponding rotation axis 4 with respect to the supporting structure 2 from the inactive position to at least one first active position and to at least one second active position, which is arranged between the inactive position and the first active position or vice versa.

[0048] In the accompanying figures, which show the device for feeding yarn or yarns according to the invention as a whole, the three yarn fingers 3 that are shown are each arranged in one of these three positions. In particular, in FIG. 3, the yarn finger 3 arranged to the rear is in the inactive position, the yarn finger 3 that is arranged at the front is in the first active position, while the yarn finger 3 that is interposed between them is in the second active position or plated position. FIGS. 9 to 11 show the three positions that can be assumed by a yarn finger 3. More particularly, FIG. 9 shows a yarn finger 3 in the inactive position, FIG. 10 shows a yarn finger 3 in the second active position or plated position, and FIG. 11 shows a yarn finger 3 in the first active position.

[0049] It should be noted that, according to the requirements, the intermediate position can be provided for each yarn finger 3 or only for some of them.

[0050] Conveniently, the device for feeding yarn or yarns according to the invention comprises means 13 for detecting the rotational position at least of the yarn fingers 3 for which the possibility to be moved to the second active position is provided.

[0051] Preferably, the means 13 for detecting the rotational position of the yarn fingers 3 comprise a Hall-effect detector which is interposed between the yarn finger 3 to be controlled and the supporting structure 2.

[0052] More particularly, the Hall-effect detector comprises a magnetic element 14, constituted for example by a small magnet, which is applied to a portion of the corresponding yarn finger 3, and a corresponding linear magnetic Hall-effect sensor 15, which is arranged on an electronic control board 16 connected to the supporting structure 2.

[0053] The electric coils 9a, 9b are connected to an electronic control board 16 which supplies power to the electric coils 9a, 9b and therefore moves the yarn fingers 3 according to a knitting program which is preset in an electronic control element 17 which supervises the operation of the machine on which the device for feeding yarn or yarns according to the invention is arranged.

[0054] The rotational position of the yarn fingers 3 for which the second active position is provided is activated and controlled, by means of a control system in a closed-loop feedback, shown schematically in FIG. 12 and designated generally by the numeral 18, by the electronic control board 16 which is connected to the means 13 for detecting the rotational position of the yarn finger 3 and which controls the power supply of the electric coils 9a, 9b as a function of the rotational value detected by said detection means 13. Essentially, in the closed-loop feedback control system 18, the value that corresponds to the rotational position of the yarn finger 3 detected by the linear magnetic Hall-effect sensor 15 is compared with a reference value that corresponds to the desired rotational position, which can be stored by self-learning in the electronic control element 17, and the difference between these two values is used, by means of a PID controller 19, in order to supply power to the pair of electric coils 9a, 9b of the corresponding yarn finger 3 so as to vary the rotational position of said yarn finger 3.

[0055] The operation of the device for feeding yarn or yarns according to the invention is evident from what has been described and illustrated, and in particular it is evident that by means of the electric power supply of a pair of electric coils 9a, 9b it is possible to actuate individually the corresponding yarn finger 3 arranged between them, causing its transition from the inactive position to the first active position or to the second active position and vice versa as a function of the various production requirements.

[0056] In practice, the electronic control element 17 that supervises the operation of the machine supplies power, by means of the electronic control board 16, to the various pairs of electric coils 9a, 9b on the basis of preset knitting programs so as to move to the first active position or to the second active position the yarn fingers 3 that must supply yarn to the needles that are moved to knit at the feed or drop at which the device for feeding yarn or yarns is arranged.

[0057] It should be noted that due to the fact that the electric coils 9a, 9b that generate the magnetic field by means of which the individual rotation of the yarn fingers 3 is performed are associated with static components, constituted by the plates 12, of the device for feeding yarn or yarns, there are no problems of fatigue failure of the electrical wires for supplying power to the electric coils 9a, 9b. For this reason, the device for feeding yarn or yarns according to the invention has a distinctly higher reliability and durability than the devices for feeding yarn or yarns with electromagnetic actuation of the known type.

[0058] Furthermore, the particular arrangement of the shielding elements, constituted by the plates 12, and their use to support the electric coils 9a, 9b allows to avoid actuation interference between contiguous yarn fingers 3 and at the same time to contain acceptably the space occupation of the device for feeding yarn or yarns along a direction that is parallel to the rotation axis 4.

[0059] In practice it has been found that the device for feeding yarn or yarns according to the invention achieves fully the intended aim, since it retains the advantages of the devices for feeding yarn or yarns with electromagnetic actuation of the known type as regards simplicity in installation and management, precision and repeatability in operation, and moreover ensures higher durability and reliability, reducing the number of maintenance interventions required in order to maintain its functionality.

[0060] The device for feeding yarn or yarns thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims; thus, for example, for each yarn finger 3 there might be a single coil and the shape of the coils might be different from the cylindrical one shown; furthermore, all the details may be replaced with other technically equivalent elements.

[0061] In practice, the materials used, so long as they are compatible with the specific use, as well as the dimensions, may be any according to the requirements and the state of the art.

[0062] The disclosures in Italian Patent Application No. 102017000057890 from which this application claims priority are incorporated herein by reference.

[0063] 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.