OPEN-TYPE CIRCULAR KNITTING MACHINE FOR THE OPEN AND WIDTH-VARIABLE WEB PRODUCTION WITH A KNITTED FABRIC TAKE-DOWN AND/OR COLLECTING ASSEMBLY

Abstract

An open-type knitting machine for the open and width-variable web production with a fabric take-down and/or collecting assembly, including a basement and a knitting head provided with a needle-holding element having a plurality of needles arranged around a central axis. A first active needle and a last active needle of the plurality delimit between them a dead zone of the needle-holding element without active needles, and an operating zone shaped as an arc of circle and provided with active needles for producing a partially tubular knitted fabric. A take-down and/or collecting assembly for the knitted fabric under production is arranged downstream from the knitting head with respect to a feeding direction of the knitted fabric. The knit-ting machine further comprises devices for adjusting the angular position of the take-down and/or collecting assembly with respect to the dead zone of the needle-holding element around the central axis.

Claims

1. An open-type circular knitting machine for the open and width-variable web production with a knitted fabric take-down and/or collecting assembly, comprising: a basement; a knitting head mounted onto the basement and comprising: at least a needle-holding element having at least a plurality of needles arranged around a central axis; a first active needle and a last active needle of said plurality delimiting between them a dead zone of the needle-holding element without needles and/or without active needles, and an operating zone shaped as an arc of circle and provided with active needles; control means operatively connected at least to the active needles so as to selectively actuate said active needles in order to produce an open knitted fabric; a take-down and/or collecting assembly for the knitted fabric under production, arranged downstream from the knitting head with respect to a feeding direction of said knitted fabric under production, wherein said take-down and/or collecting assembly is integral with the needle-holding element during the production of the knitted fabric; wherein it comprises devices for adjusting the angular position of the take-down and/or collecting assembly with respect to the dead zone of the needle-holding element around the central axis.

2. The machine according to claim 1, wherein the take-down and/or collecting assembly is hung below the knitting head, and wherein the adjusting devices are operatively placed between said take-down and/or collecting assembly and the knitting head.

3. The machine according to claim 1, wherein the adjusting devices are of the manual adjustment type or comprise at least a motor configured for moving the take-down and/or collecting assembly with respect to the needle-holding element.

4. The machine according to claim 1, comprising devices for varying the number of active needles in the operating zone so as to adjust the height of the knitted fabric; wherein the adjusting devices comprise a control unit operatively connected to a motor configured for moving the takedown and/or collecting assembly with respect to the needle-holding element; wherein the control unit is configured for receiving as input the number of active needles, calculating the correct position of the takedown and/or collecting assembly corresponding to said number of active needles, and for providing as output the angular position of the take-down and/or collecting assembly or for accordingly controlling the motor and directly adjusting said angular position.

5. The machine according to claim 1, wherein the adjusting device s comprise: a first disc integral with the needle-holding element; a second disc integral with the take-down and/or collecting assembly; wherein the first disc faces the second disc and is coaxial therewith; wherein the first disc is en-gageable with the second disc in a plurality of angular positions; wherein the first disc is movable with respect to the second disc between a first adjustment position in which the first disc can rotate with respect to said second disc, and a second operating position in which the first disc is integrally blocked to the second disc.

6. The machine according to claim 1, wherein the take-down and/or collecting assembly comprises: spreading devices configured for opening and stretching in a single layer the knitted fabric produced by the knitting head, wherein the spreading devices comprise at least a spreading bar; and/or devices for piling up the knitted fabric stretched, wherein the piling-up devices comprise at least a collecting roll; and/or take-down elements for the knitted fabric produced, wherein the take-down elements comprise at least a take-down roll.

7. A method for adjusting the width of a knitted fabric produced on an open-type circular knitting machine for the open and width-variable production of the web with a knitted fabric take-down and/or collecting assembly, comprising the steps of setting the width of a dead zone of a needle-holding element of said machine delimited by a first active needle and by a last active needle of at least a plurality of active needles arranged along an operating zone shaped as an arc of circle and developing around a central axis; adjusting the angular position of the take-down and/or collecting assembly of said machine with respect to the dead zone.

8. The method according to claim 7, wherein adjusting the angular position includes: rotating and then blocking said take-down and/or collecting assembly with respect to the needle-holding element and around said central axis.

9. The method according to claim 7, wherein adjusting the angular position comprises angularly centering the take-down and/or collecting assembly of said machine with respect to the dead zone.

10. The method according to claim 7, wherein setting the width of the dead zone comprises activating or deactivating at least a needle of said plurality of needles starting from the first active needle and/or from the last active needle.

Description

[0060] This description shall be made below with reference to the accompanying drawings, provided to a merely indicative and therefore non-limiting purpose, in which:

[0061] FIG. 1 shows an open-type circular knitting machine for the open and width-variable web production with a knitted fabric take-down and/or collecting assembly according to the present invention;

[0062] FIG. 2 shows a magnified view of a portion of the machine of FIG. 1;

[0063] FIG. 3 shows a perspective view of a collecting set associated to a needle-holding element, both belonging to the machine of FIG. 1;

[0064] FIG. 4 shows an exploded view of a portion of the set of FIG. 3;

[0065] FIG. 5 shows an exploded view of a detail of the set of FIGS. 3 and 4;

[0066] FIG. 6 shows an element of the detail of FIG. 5 from a different point of view;

[0067] FIG. 7 is a side view of the set as in FIGS. 2 and 3;

[0068] FIG. 8 is a side view of the set as in FIGS. 2 and 3 with some parts removed for better showing others;

[0069] FIG. 9 schematically shows the view of FIG. 8 in accordance with a variant of embodiment of the collecting set;

[0070] FIG. 10 is a top view of the set as in FIG. 3;

[0071] FIGS. 11 and 12 schematically show the view of FIG. 10 with the set in respective operating positions;

[0072] FIG. 13 shows a perspective view of a variant of embodiment of the set of FIG. 3.

[0073] With reference to the figures mentioned above, numeral 1 globally refers to an open-type circular knitting machine for the open and width-variable web production with a knitted fabric take-down and/or collecting assembly 2, according to the present invention. A take-down and/or collecting set, comprising this take-down and/or collecting assembly, is globally referred to with numeral 100. In FIGS. 1, 3, 7, 8, 10 and 13 the take-down and/or collecting assembly 2 and set 100 perform a collecting function only, since take-down elements are absent. In FIG. 9 the assembly 2 schematically shown is a take-down and collecting assembly, since it is provided with take-down elements 60, too. In the examples disclosed below, assemblies performing the take-down function only are not detailed, though they belong to the scope of the present invention.

[0074] The circular knitting machine 1 comprises (FIG. 1) a basement 3, which is the supporting structure of the machine 1, and a knitting head 4 mounted onto the basement 3 and provided with a needle-holding element 5, with a plurality of needles 6, 7 movably mounted to the needle-holding element (5), with control means (not shown since of known type, e.g. control cams) apt to selectively actuate the plurality of needles so as to enable the production of a knitted fabric “T”. The machine 1 shown is of the type with rotating needle-holding element 5 and non-rotating control means.

[0075] As better shown in FIG. 2, the needle-holding element 5 comprises a needle cylinder 8 provided with a first plurality of needles 6 having terminal ends placed on an upper edge of the needle cylinder 8. The needle-holding element 5 further comprises a needle plate 9 provided with a second plurality of needles 7 having terminal ends placed on a radially peripheral edge of said plate 9. Said terminal ends of the needles 6, 7 are directed towards an operating zone 10 (FIG. 2) in which occurs the formation of the knitted fabric “T”, which then gets down into the needle cylinder 8.

[0076] The machine 1 shown according to the invention is of the type for the open and width-variable web production. As a matter of fact, the needles 6, 7 are arranged in series on the needle-holding element 5 (in particular on the needle cylinder 8 and on the needle plate 9) along respect paths shaped as an arc of circle smaller than 360°, as can be seen schematically in FIGS. 10, 11 and 12. In other words, the operating zone 10 is an arc of circle. A first needle 6a and a last needle 6b of the first plurality of needles 6 delimit in between a zone 11 without needles. In the embodiment shown (FIG. 10), this zone 11 without needles develop on angle “a” of about 40°. Similarly, a first needle 7a and a last needle 7b of the second plurality of needles 7 of the needle plate 9 delimit in between a zone without needles placed on the zone 11 without needles of the needle cylinder 8. The whole circumference of the needle-holding element 5 is therefore divided into the operating zone 10 shaped as an arc of circle, in which the knitted fabric “T” is formed, and into a complementary zone 11, known as “dead zone”, in which the fabric knitted “T” is not formed. The knitted fabric “T” thus formed therefore has the shape of a cylinder with a partial circumferential development, i.e. open on the dead zone.

[0077] The machine 1 further comprises devices (known per se and not shown) for varying the number of active needles 6, 7 both of the needle cylinder 8 and of the needle plate 9 so as to widen the dead zone 11 and thus reduce the operating zone 10 and vary in this manner the height of the knitted fabric “T” produced. The needles 6, 7 can be made inactive, e.g. not actuating them and/or moving them away from the operating zone 10 and/or dismounting them. The needles 6, 7 can be made inactive starting from the last needle 6b (FIGS. 10, 11 and 12). In FIG. 11, the dead zone has a width “a” and the knitted fabric “T” is thus formed on the operating zone 10 defined by the arc of circle between the last needle 6b, 7b and the first needle 6a, 7a. In the example shown in FIG. 12, the dead zone, which in FIG. 11 has a width “α”, is widened by reducing the number of active needles starting from the last needle 6b, until a width “β” is achieved (FIG. 12). In FIG. 12 the last active needle 6b′ is no longer the last needle 6b close to the zone without needles 11. All the needles 6 between the one referred to with numeral 6b′ and the last one 6b are made inactive. The knitted fabric “T” is thus formed on the operating zone 10 defined by the arc of circle between the last active needle 6b′, 7b′ and the first needle 6a, 7a.

[0078] During the formation of the knitted fabric “T”, the needle-holding element 5 of the machine 1 rotates continuously around a central axis “X-X” and suitable devices (known per se and not shown) allow at at each revolution to begin thread feeding on the first active needles 6a, 7a (of the operating zone 10) and to interrupt feeding on the last active needle (6b or 6b′).

[0079] The basement 3 comprises an upper ring or supporting element 12 (FIGS. 1 and 2), onto which the knitting head 4 is mounted so that the needle-holding element 5 can rotated with respect to said upper supporting element 12 around said central axis “X-X” and comprises a lower base 13, or cross joint, designed to be laid onto the ground. The upper supporting element 12 and the needle-holding element 5 are coaxial with the central axis “X-X”. The basement 3 further comprises two supporting legs 14. A motor, not shown, moves in rotation the needle-holding element 5.

[0080] Between the upper ring 12 and the lower base 13 a collecting space without elements of the basement 3 is defined, which is designed to house the collecting assembly 2 for the fabric produced by the machine 1.

[0081] The collecting assembly 2 shown is hung to the needle-holding element 5 and supported by the latter. During the production of the knitted fabric “T” it rotates integrally with the needle-holding element 5 in the collecting space. In other embodiments, not shown, the take-down and/or collecting assembly 2 is not hung to but rests on the ground or the basement 3 and is anyhow operatively connected to the needle-holding element 5 so as to rotate integrally with the latter during production.

[0082] The collecting assembly 2 shown (which can be seen better in FIGS. 3, 7, 8 and 10) comprises a supporting structure 15 defined by a beam 16 and by two side plates 17, 19 developing from opposite ends of the beam 16 and orthogonal thereto. The side plates 17, 18 are parallel and face each other. The beam 16 develops perpendicular to the central axis “X-X”. The collecting assembly 2 is symmetrical with respect to a plane of symmetry “P” (FIGS. 10, 11 and 12) containing the central axis “X-X”.

[0083] The supporting structure 15 supports spreading devices 19 configured for opening and stretching in a single layer the knitted fabric “T” produced by the knitting head 4, and devices for piling up 20 the knitted fabric “T” once stretched.

[0084] The spreading devices 19 (FIGS. 3, 8 and 9) comprise a spreading bar 21 mounted, preferably in a fixed manner, onto the supporting structure 15 and configured for causing two side edges of the knitted fabric “T” to open by progressively moving away from each other. The spreading bar 21 extends longitudinally between two of its terminal ends 22, 23, each one being firmly connected to a respective side plate 17, 18, of the supporting structure 15. The spreading bar 21 is placed opposite the beam 16 and basically extends on the whole length of said beam 16. The spreading bar 21 shown has a curved shape defined by a central portion 24 and by two side portions 25, 26. The two side portions 25, 26 progressively move away from the beam 16 and converge towards the central portion 24, which has a maximum distance from the beam 16 and is apt to guide a central portion of the knitted fabric “T” when coming down. The spreading bar 21 has global shape as a rounded “V”, i.e. its central portion 24 is curved, e.g. as an arc of circle, and its two portions 25, 26 are rectilinear. The spreading bar 21 is basically symmetrical with respect to a vertical plane of symmetry “P” containing the central axis “X-X” of the needle-holding element 5 and is arranged in a horizontal plane. The spreading bar 21 is mounted onto the supporting structure 15, e.g. by means of slides placed and the terminal ends 22, 23, so as to adjust the distance of the central portion 24 from the beam 16.

[0085] The supporting structure 15 also supports the devices for piling up 20 the knitted fabric “T” stretched, which are placed below the spreading devices 19, i.e. downstream from the spreading devices 19 with respect to a feeding direction of the knitted fabric “T” coming from the knitting head 4. The piling-up devices 19 are defined by a collecting roll 27 (or fabric roller) with rectilinear axis (FIGS. 1, 3, 8, 9). The collecting roll 27 is turnably mounted onto the supporting structure 15 so as to freely rotate around a respective, basically horizontal axis of rotation. The collecting roll 27 is designed to collect the knitted fabric “T” produced by the machine 1 as a bobbin, winding it thereon and in a single continuous layer. The collecting roll 27 extends between two of its terminal ends, on which it is turnably connected to the aforesaid side plates 17 and 18. The axis of rotation of the collecting roll 27 is oriented parallel to the longitudinal development of the beam 16, i.e. orthogonal to the plane of symmetry of the spreading bar 21.

[0086] The piling-up devices 20 comprise a first and a second winding roller 28, 29 turnably mounted onto the supporting structure 15 so as to rotate around respective axes of rotation that are basically horizontal and moved in rotation by respective motors 28a, 29a (FIGS. 3, 8 and 13). The winding rolls 29 extend between two of their longitudinal ends, on which they are turnably connected to the aforesaid side plates 17 and 18. The axes of rotation of the winding rolls 28, 29 are oriented parallel to the longitudinal development of the beam 16. The first and the second winding roll 28, 29 are placed below the collecting roll 27 and both act along respective contact lines upon the fabric wound as a bobbin onto the collecting roll so as to impart a rotation thereto and cause the knitted fabric “T” to be continuously wound onto the collecting roll 27. The winding rolls 28, 29 cannot move whereas the collecting roll 27 is free to vertically move on dedicated guides. The collecting roll 27 rests on the winding rolls 28, 29 and, while collecting the fabric produced as the bobbin diameters increases, vertically moves within the guides.

[0087] The collecting assembly 2 comprises a first unfolding roll 30 configured for interacting with the knitted fabric “T” moving towards the collecting roll 27 so as to stretch it horizontally by spreading it towards two side ends of the first unfolding roll 30. The first unfolding roll 30 is mounted above the winding rolls 28, 29 and is placed close to the beam 16. The first unfolding roll 30 is turnably mounted onto the supporting structure 15 so as to freely rotate around a respective, basically horizontal axis of rotation. The first unfolding roll 30 extends between two of its terminal ends, on which it is turnably connected to the aforesaid side plates 17 and 18. The axis of rotation of the the first unfolding roll 30 is oriented parallel to the longitudinal development of the beam 16. With reference to the path of the knitted fabric “T” during production, the first unfolding roll 30 is placed downstream from the spreading bar 21 and upstream from the winding rolls 28, 29.

[0088] A second unfolding roll 31 is positioned close to the first winding roll 28. The second unfolding roll 31 is turnably mounted onto the supporting structure 15 so as to freely rotate around a respective, basically horizontal axis of rotation. The second unfolding roll 31 extends between two of its terminal ends, on which it is turnably connected to the aforesaid side plates 17 and 18. The axis of rotation of the the second unfolding roll 31 is oriented parallel to the longitudinal development of the beam 16. With reference to the path of the knitted fabric “T” during production, the second unfolding roll 31 is placed downstream from the first unfolding roll 30 and upstream from the winding rolls 28, 29.

[0089] The collecting assembly 2 further comprises a guiding ring 32 mounted, preferably in a fixed manner, onto the supporting structure 15 above the spreading bar 21. The guiding ring 32 is arranged in a basically horizontal plane and is configured for guiding the knitted fabric “T” produced by the machine 1 when coming down directly as a single layer from the needle-holding element 5, towards the spreading bar 21. The guiding ring 32 delimits inwardly a passage in which said knitted fabric “T” gets down, sliding on a radially inner surface of said guiding ring 32. The guiding ring 32 is apt to guide and unfold the knitted fabric “T”. The guiding ring 32 laterally extend from the same front side of the beam 16 from which also the spreading bar 21 laterally extends, and it partially overlaps said spreading bar 21. The guiding ring 32 has a basically circular shape and is basically coaxial with the needle-holding element 5. The guiding ring 32 is fixed on a central portion of the beam 16. In the embodiment shown, the guiding ring 32 does not define a complete circle but is formed by a curved bar whose ends are firmly connected to the beam 16.

[0090] The knitted fabric “T”, coming from the operating zone 10 of the needle-holding element 5, gets down into the needle-holding element 8 shaped as an incomplete tube, through the guiding ring 32 as an incomplete tube and then outside the spreading bar 21 opening and unfolding itself. Then the knitted fabric “T”, now completely open in a single layer, is partially wound onto the first unfolding roll 30 and reaches the second unfolding roll 31 onto which it is partially wound by getting below the latter. Eventually, the knitted fabric “T” is wound as a bobbin onto the collecting roll 27 thanks to the rotation of the winding rolls 28, 29.

[0091] A supporting frame 33 is firmly connected to the supporting structure 15 and connects the collecting assembly 2 to the needle-holding element 5, in particular with the needle cylinder 8 (FIGS. 3, 4, 7, 8, 13). In the embodiment shown, the supporting frame 33 has a box-shaped structure removably joined to the needle cylinder 8, e.g. by means of screws or bolts, or welded thereto.

[0092] Between the supporting frame 33 and the supporting structure 15 of the collecting assembly 2 are operatively placed devices 34 for adjusting the angular position of the collecting assembly 2 with respect to the needle-holding element 5 around the central axis “X-X” (FIGS. 1, 3, 4, 5, 6, 7, 8, 13).

[0093] The adjusting devices 34 shown in the embodiment of FIGS. 1 to 12 comprise a first disc 35 firmly connected to the supporting frame 33, and a second disc 36 firmly connected to the supporting structure 15 of the collecting assembly 2. The first disc 35 and the second disc 36 are coaxial with the central axis “X-X”.

[0094] The first disc 35 (FIGS. 3, 4, 5 and 6) has a first upper face 37 provided with a pair of first grooves 38, each being apt to house a first supporting bar 39 firmly connected to the supporting frame 33. The first supporting bars 39 are joined, e.g. by means of screws or bolts, to the supporting frame 33 and develop parallel and horizontal on opposite sides of said supporting frame 33. The supporting bars 39 are further joined to the first disc 35 e.g. by means of screws inserted into suitable holes made in the first face 37. The first disc 35 has a central through hole 40 and an annular hollow 41 obtained on the first face 37 around said through hole 40 (FIG. 5). The grooves 38 are rectilinear and parallel and lie on opposite sides of the central through hole 40. A second face 42 of the first disc 35, opposite the first face 37, has a first toothing 43 arranged close to a radially peripheral edge of the second face 42. The first toothing 43 comprises a plurality of teeth 44 arranged in series along a circular path (FIG. 6). Each of the teeth 44 of said first toothing 43 develops away from said second face 42, along an axial direction. An annular projection 45 is further arranged on the second face 42 and around the central through hole 40.

[0095] The second disc 36 has a first lower face 46 provided with a pair of second grooves 47 (which can be partially seen in FIG. 5), each being apt to house a second supporting bar 48 (FIGS. 3 and 4) which is in its turn firmly joined to the supporting structure 15. In the embodiment shown, the second supporting bars 48 are joined to a plate 49 which is in its turn joined to the beam 16. In particular, the plate 49 develops projecting from the front side of the beam 16 and is further supported by a pair of reinforcing bars 50 connected to the spreading bar 21. The second supporting bars 48 are parallel to each other and to the first supporting bars 39. The second supporting bars 48 are further joined to the second disc 36, e.g. by means of screws inserted into suitable holes made in the second face 42. A second face 51 of the second disc 36 (FIG. 5), opposite the first face 46, has a second toothing 52 arranged close to a radially peripheral edge of the second face 51. The second toothing 52 comprises a plurality of teeth 53 arranged in series along a circular path. Each of the teeth 53 of said second toothing 52 develops away from said second face 51, along an axial direction. A central shaft 54 develops axially from the second face 51 coaxial with the second toothing 52. The central shaft 54 has a base portion 54A with a smaller diameter and an end portion 54B with a greater diameter so as to define an annular retaining surface 55 directed towards the second face 51. Moreover, an annular groove 56 is defined in the second face 51 and around the base of the central shaft 54.

[0096] The first disc 35 and the second disc 36 face each other and are coaxial. In particular, the second face 42 of the first disc 35 faces the second face 51 of the second disc 36. The central shaft 54 of the second disc 36 is inserted into the central through hole 40 of the first disc 35 and the end portion 54B partially protrudes from the first face 37 of said first disc 35. A ring nut 57 with a thrust block 58 is screwed onto the end portion 54B. The thrust block 58 is housed inside the annular hollow 41. Moreover, a retaining ring 59 (in two pieces in the construction solution shown) is mounted around the base portion 54A of the central shaft 54, so as to slide axially onto said base portion 54A, and is joined, e.g. by means of screws, to the annular projection 45 of the first disc 35. A portion of the retaining ring 59 faces the annular retaining surface 55 of the second disc 36.

[0097] As can be better seen in FIG. 3, the supporting frame 33, the adjusting devices 34, the first and second bars 39, 48 and the plate 49 are substantially placed inside the guiding ring 32.

[0098] The first disc 35 and the second disc 36 are axially movable one with respect to the other between a first adjusting position and a second operating position.

[0099] In the first adjusting position, the first toothing 43 and the second toothing 52 are axially spaced away from each other so that the teeth 53 of the second toothing 52 do not even partially lie between the teeth 44 of the first toothing 43. In order to obtain this configuration, the ring nut 57 is partially or fully unscrewed. If the ring nut is fully unscrewed and e.g. removed from the central shaft 54, said central shaft 54 cannot however be fully taken out from the central through hole 40 (and the discs 35, 36 cannot be fully disconnected one from the other), since the retaining ring 59 integral with the first disc 35 abuts against the annular retaining surface 55 of the second disc 36. In this first adjusting position, the first disc 35 and the second disc 36 can be freely rotated one with respect to the other around the central axis “X-X”.

[0100] In the second operating position, the ring nut 57 is fully screwed onto the central shaft 54 so as to tighten the first disc 35 against the second disc 36. The first toothing 43 and the second toothing 52 are mutually engaged (the teeth 53 of the second toothing 52 are between the teeth 44 of the first toothing 43) so that every relative rotation between the first disc 35 and the second disc 36 around the central axis “X-X” is prevented. When the discs 35, 36 are in the second operating position, the collecting assembly 2 is integral with the needle-holding element 5 and can rotate with said needle-holding element 5, being dragged by the latter. Once the ring nut 57 is unscrewed, either manually or using tools, the second disc 36 moves axially away from the first disc 35, under the effect of the weight of the collecting assembly 2, thus reaching the first adjusting position. In this first position it is possible to adjust the angular position of the collecting assembly 2 with respect to the needle-holding element 5 around the central axis “X-X”, e.g. by manually acting upon said collecting assembly 2. Once the angular position is adjusted, the ring nut 57 is again screwed until the discs 35, 36 reach the second operating position.

[0101] The toothings 43, 52 of the discs 35, 36 just described above enable a discrete adjustment of the mutual angular position. The number of angular positions is a finite number related to the number of teeth 44, 53.

[0102] According to a variant of embodiment, not shown, of the adjusting devices 34, the first and the second disc 35, 36 do not have toothings but respective friction surfaces which, when tightened one against the other, prevent any relative rotation between the discs 35, 36. These friction surfaces are preferably made of composite materials including e.g. aramide, resin, ceramic, aluminum oxide, graphite, carbon. In this case, the number of angular positions is an infinite number (continuous adjustment).

[0103] According to further variants of embodiment, not shown, the discs 35, 36 (either with teeth or with friction materials) are moved axially (so as to move them closer or away from each other) and/or in rotation by means of motors.

[0104] According to a different embodiment, schematically shown in FIG. 13, the adjusting devices comprise a mechanical drive 34A (schematically shown as a box in FIG. 13), which can be actuated manually, e.g. by means of a crank, or can be motorized. The mechanical drive 34A can comprise e.g. a toothed gear connected to the collecting assembly 2, and a crown gear connected to the supporting frame 33, or a set of gears operatively placed between the collecting assembly 2 and the supporting frame 33. In this case again, the number of angular positions is an infinite number (continuous adjustment).

[0105] In one embodiment, schematically shown in FIG. 9 only, the assembly 2 is a take-down and collecting assembly and further comprises take-down elements 60 which cause the knitted fabric “T” to get down under tension into the collecting space. In the example shown, the take-down elements 60 comprise several take-down rolls, placed in series one to the other, acting upon the knitted fabric “T” so as to force the advancement thereof towards the collecting roll 27. FIG. 9 shows by way of example three take-down rolls 61, 62 ad 63, which are placed in series one to the other and which the knitted fabric “T” gets through sequentially. The take-down rolls 61, 62, 63 are placed, with respect to the direction of advancement of the knitted fabric “T”, between the first spreading roll 30 and the second spreading roll 31. The collecting rolls 61, 62, 63 are turnably mounted onto the supporting structure 15 so as to freely rotate around respective axes of rotation which are basically rectilinear, horizontal and parallel to the collecting roll. Each one of the take-down rolls 61, 62, 63 extends between two of its longitudinal ends, on which it is turnably connected to the aforesaid side plates 17 and 18. The piling-up devices 20, the spreading devices 19 and the take-down elements 60 are integral with each other in the rotation around the central axis “X-X” (both during adjustment and during production).

[0106] The machine 1 further comprises an electronic control unit, not shown, for managing its operations.

[0107] In one embodiment in which the adjusting devices 34 are motorized, the electronic control unit is operatively connected to the motor or motors of said devices 34 and is configured for controlling the motor or motors based on input data related to the desired angular position of the collecting assembly 2. The operator can e.g. insert the desired angular value into the control unit by means of input devices (keyboard, touchscreen, mouse, etc.) and the control unit controls the motor so that it moves the collecting assembly accordingly. In a variant of embodiment, the electronic control unit is configured for receiving as input, instead of the desired angular value, a value related to the desired fabric height, such as the width of the dead zone or the number of active needles or the number of deactivated needles, and for controlling the motor or motors accordingly so that it moves/they move the collecting assembly accordingly.

[0108] In another variant of embodiment, the electronic control unit is operatively connected to the devices for varying the number of active needles and is configured for receiving as input a value related to the desired fabric height, for calculating the number of active needles required for obtaining this height, for controlling the devices for varying the number of active needles so that they activate the required needles, and for controlling the motor or motors so that it moves/they move the collecting assembly accordingly.

[0109] In another variant of embodiment in which the adjusting devices 34 are manual, the electronic control unit is operatively connected to the devices for varying the number of active needles and is configured for receiving as input a value related to the desired fabric height, for calculating the number of active needles required for obtaining this height, for controlling the devices for varying the number of active needles so that they activate the required needles, and for providing as output (e.g. on a screen) the angular position of the collecting assembly (which is then adjusted manually).

[0110] The collecting assembly 2, the adjusting devices 34 and the supporting frame 33 make a collecting set according to the present invention, which can be firmly connected to the knitting head of a circular machine, even if already existing (retrofitting).

[0111] In use and according to a method for adjusting the width of a knitted fabric “T” and with a process for producing a knitted fabric “T” according to the present invention, the machine 1 is preset for producing a knitted fabric “T” having a predefined height. To this purpose, the operator sets the width of the operating zone 10 (and thus of the dead zone 11) by activating or deactivating a given number of needles 6, 7. Then, by acting upon the adjusting devices 34 according to the above description, it adjust the angular position of the collecting assembly 2 accordingly, so as to angularly center the collecting assembly 2 with respect to the dead zone 11 (i.e. with respect to the operating zone 10). Starting from the situation shown in FIG. 11, in which all the needles 6 present are active and the plane of symmetry “P” of the collecting assembly 2 is centered with respect to the zone 11 without needles (and thus with respect to the operating zone 10 and to the knitted fabric “T” produced), the operator deactivates a plurality of needles 6 starting from the last needle 6b adjacent to the zone without needles 11 as far as the needle referred in FIG. 12 with numeral 6b′. The dead zone of FIG. 9 (made up of the zone without needles and of inactive needles) is thus wider than the one in FIG. 11. In order to center again the collecting assembly 2 with respect to the new dead zone 11, the operator rotates said collecting assembly 2 of an angle “γ”. Now the operator can begin production.